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Spring 2012
Issue #104 CONTACT! ISSUE 104 PAGE 1
PO BOX 1382 Hanford CA 93232-1382 United States of America 559-584-3306 Editor@CONTACTMagazine.com
Volume 18 Number 3 Spring 2012
Issue #104 MISSION CONTACT! Magazine is published quarterly by Aeronautics Education Enterprises (AEE), established in 1990 as a nonprofit corporation, to promote aeronautical education. CONTACT! promotes the experimental development, expansion and exchange of aeronautical concepts, information, and experience. In this corporate age of task specialization many individuals have chosen to seek fresh, unencumbered avenues in the pursuit of improvements in aircraft and powerplants. In so doing, they have revitalized the progress of aeronautical design, particularly in the general aviation area. Flight efficiency improvements, in terms of operating costs as well as airframe drag, have come from these efforts. We fully expect that such individual efforts will continue and that they will provide additional incentives for the advancement of aeronautics. EDITORIAL POLICY CONTACT! pages are open to the publication of these individual efforts. Views expressed are exclusively those of the individual authors. Experimenters are encouraged to submit articles and photos of their work. Materials submitted to CONTACT! are welcomed and will become the property of AEE/CONTACT! unless other arrangements are made. Every effort will be made to balance articles reporting on commercial developments. Commercial advertising is not accepted. All rights with respect to reproduction, are reserved. Nothing whole or in part may be reproduced without prior permission of the publisher. SUBSCRIPTIONS Four issue subscription in U.S. funds is $20.00 for USA, $24.00 for Canada and Mexico, $32.00 for overseas air orders. CONTACT! is mailed to U.S. addresses at nonprofit organization rates on a irregular schedule, trying to mail in January, April, July and October. Please allow time for processing and delivery of first issue. ADDRESS CHANGES / RENEWALS The last line of your label contains the number of your last issue. Please check label for correctness. This magazine does not forward. Please notify us of your date of address change consistent with our bimonthly mailing dates to avoid missing any issues. COPYRIGHT 2012 BY AEE, Inc.
Sun ‘n Fun this year was a little different for me as again I didn’t have a booth, but this time CONTACT! Magazine founder Mick Myal joined me. Mick has helped in the booth at AirVenture a couple of times, but this was the first time we have ever been at Sun ‘n Fun together– and I enjoyed his company. Although the mainstream aviation media continues to call it a successful show, by my account the numbers were the lowest I’ve seen in a decade– especially homebuilts. But I did find one homebuilt that epitomizes the spirit of experimental aviation and managed to twist the arm of the designer and builder to write this issue’s feature, the BK1. I’ve been following Bruce King’s progress for several years, but he’s finally reached the point of making plans available to the com-
munity, so we mutually decided it was time to tell his story in the pages of CONTACT! Magazine.
THE SAA IS BACK The Sport Aviation Association was founded in the 1990s by Paul H. Poberezny, but it only lasted a short while before shutting down. We are happy to announce that it’s in the process of being re-formed by South Carolinian Ed Fisher after a little over six years of dormancy. Homebuilt Hall of Famer and aircraft designer Fisher (featured on page 21 of this issue) is a long-time Continued on page 23
3 BK1– Don’t Give Up Your Dreams.— Bruce King describes the journey he took to arrive at a homebuilt aircraft designed for those who want to have a fun yet affordable and practical airplane. 10 Chris Walterson’s Dragonfly C-FLYV.— One of the original directdrive, intercooled, turbocharged Subaru engines to successfully fly has been humming away for 15 years. Chris offers this update. 12 The New Skyactiv-D Diesel Engine from Mazda.— Mazda does it again by developing a small, lightweight but powerful diesel engine utilizing advanced technology. This time they’ve dropped the compression ratio to 14:1 and eliminated a lot of weight in the process. 14 The Application of automotive Technology– Pathway to a Lower Cost LSA?.— Jerry Olszewski spent the majority of his career in the automobile manufacturing industry, looking at ways to save time and money during production, experimenting with new materials and manufacturing processes. In this article, Jerry discusses some of the ways that these methods could translate into easier-to-build aircraft. 21 Update on Raceair Designs and Lil’ Bitts.— Oscar Zuniga continues the CONTACT! Magazine article from issue #92 where Ed Fisher debuted his Lil’ Bitts biplane. It’s time to bring the plans to market. 22 Tip Tanks: Design and Fabrication for Designers and Homebuilders.— Our very own Mick Myal has written the book (literally) on the design and fabrication of tip tanks. On the cover: Bruce King in his BK1 prototype, now set for plans delivery.
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BK1.3 Prototype #2 at Sun-N-Fun 2012. Its mission? To bring affordable flying to those who dream of building and flying their own aircraft, but are concerned that it just might be too expensive.
By Bruce King bruce@bkfliers.com www.bkfliers.com (210) 363-3288 Although small in appearance, the BK1 is not limited to just local, around-the-airport flying. With a large comfortable cockpit, an economy cruise speed of 130 mph, a 400 mile range (3-hour endurance with reserves) and ample baggage capacity, long cross country flights to camp-in fly-ins including the big ones at Oshkosh WI and Lakeland FL are routinely possible.
While not truly on the market yet, when it is the BK1 will be offered as a plans-only project, with a projected cost of $12,000 to $14,000, considerably low compared to any kits available in its class. For those who can afford the extra expense, there are plans in the works to offer pre-made, welded steel parts, ribs, bulkheads, landing gear legs, etc... As the market grows this could lead to full kits, quick builds, and maybe our own facility at Oshkosh…well… why not dream big? WHO IS BRUCE KING? Bruce was born in Dallas TX early in 1950, but his family moved later that year to San Antonio and he’s been there ever since. Aviation runs deep in his family. Bruce’s father was a career Air Traffic Controller and part time commercial pilot, and gave Bruce his first airplane ride in a Bonanza at the age of 4, an event he can clearly remember to this day. Bruce’s father was also his CFI, who taught him to fly in a Cessna 150 at the age of 18, with the private pilot license to come a year later. Bruce’s mother worked in an AT6 plant in WW2, a true “Rosie the Riveter.” She worked for the US Air Force as technical illustrator for training manuals until her retirement. Her illustrations used in the instrument training manual is still in use to-
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day and is exhibited on a mural in the Smithsonian Museum. Bruce met his wife Marsha during their studies at the University of Texas, Austin, and has been married for 38 years. They have two children, David and Emily, both married and in graduate school. Marsha has been Bruce’s most faithful supporter; none of this would have happened without her solidly by his side.
The wing has a low camber at the root (see Rib 1) transitioning to a higher camber at the tip. (see Rib 10)
Bruce completed his Business Management degree in 1973 and went on to Hallmark AeroTech to get his A&P license in 1977. He spent two years working on Cessna, Piper, Beech single and twins, including engine changes, overhauls, airframe disassembly, inspection, rigging, and test flying. He spent three years working on Tejas Airlines’ fleet of three Merlin Metros and four Piper Navajos in daily service before going on to spend four years as a technical writer for Fairchild and Dee Howard, where he had the run of a "green" 747 being outfitted for the King of Saudi Arabia. His resume also includes spending three years as computer programmer for banking software and includes 24 years as network engineer/support for a hospital group. Always interested in building and flying model aircraft, Bruce never cared much for plastic scale models- they had to fly. Starting younger than he can remember with balsa wood/tissue paper, in 1970 he graduated from control line, to radio control. Bruce started (bit didn’t complete) his first experimental aircraft in 1998, then finished a second one in 2002 with the first flight on June 2, 2002.
Many larger pilots have discovered most of the affordable homebuilt aircraft on the market are too small for a larger pilot. Not so for the BK1. Bruce (left) is 6 foot tall, and although we’re not exactly sure how tall this builder is, he fits well, hat and all.
FLYING THE BK1 The controls are light but not twitchy. I worked hard on the low-speed characteristics; it has a high lift wing with a unique aerodynamic twist to ensure gentle stall characteristics. The airfoil has a high camber at the tip transitioning to a lower camber at the root. For this reason, the stall begins at the wing root, where the turbulence affects the elevator, warning the pilot with a natural "stick shaker." As the stall reaches mid-wing, the nose mushes down well before aileron effectiveness is lost. The oversized horizontal and vertical stabilizers give great pitch and yaw control authority during slow flight. The ailerons have a 2:1 up/down travel differential for minimal adverse yaw.
The aircraft is fun to fly, like strapping on a set of wings. The large bubble canopy and narrow, sharply dropped nose gives the pilot an incredible view.
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In cruise you can stretch your legs out to rest your feet beyond the rudder petals, relax, and aviate with only the stick. Roll stability, similar to many low wing planes, is neutral up to about 30 degrees of bank and slightly negative beyond that. In cross country flight one can fold a map keeping the wings level with small corrections made with light pressure on the rudder pedals.
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Packing up the camping gear for the one-day trip home after spending the week at Oshkosh. There’s no cheaper way to enjoy the big show and there’s no higher honor than being asked to park under the brown arch. This might be a contender for the “dead grass” award.
The plane lifts off into ground effect between 45-50 mph indicated with an initial climb rate of 700 fpm at about 60 mph indicated. Maximum cruise speed with the 1835 cc, 65 hp Great Plains VW engine is a sport pilot compliant 138 mph at the recommend engine continuous redline of 3400 rpm- where the engine develops 60 hp. But I like a sweet spot of about 3000-3100 rpm which achieves the 130 mph cruise and the 400 mile range with reserve. These performance figures were compiled from operating the BK1.0 over many trip legs since 2004. I suggest a maximum continuous cruise of 3100 rpm which is about 45 hp and 130 mph cruise. Fuel burn at that setting is between 3-1/4 and 3-1/2 gph depending on conditions. Based on a useable fuel capacity of 15 gallons, we have a maximum endurance of about 4 hours. This makes planning a 3 hour, 400 mile cross country leg practical with good reserve, even with some headwind. If I back off the throttle to about 2700 rpm, the airspeed easily maintains about 100 mph but the fuel burn drops to about 2-1/2 gph- perfect for the weekend cruise when you have no particular place to go. Clean stall speed, confirmed by GPS, is about 48 mph. This is the no-flap speed where the nose mushes down and the BK1 does a kind of falling leaf action with one wing after the other dropping about 20-30 degrees. The indicated airspeed (where the bottom of the green arc should be) is just under 40 mph at this high of an angle of attack where the pitot tube isn’t pointing directly into the oncoming air. www.ContactMagazine.com
VW POWER The little VW engine has an 8:1 compression ratio in this new configuration from Great Plains Aircraft Supply, developed from drawings provided by our late, great friend Robert Hoover. Robert always said, "The propeller belongs on the stronger flywheel-end of the engine crankshaft." The installation consist of a beautifully machined billet aluminum hub and a steel-tube bed-style engine mount that cradles the engine using existing case mounting points at the front and rear. A 35 amp alternator is driven from a custom hub on the pulley end of the crankshaft. The starter is mounted on top of the engine and drives an automatic transmission flexplate that saves the weight of the traditional flywheel. Add the Great Plains
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modified Hummel Bird. To fit inside it, I needed to re-loft the entire fuselage. To get it off the ground, I installed a full VW (the Hummel only required a half VW). On July 2, 2002 the new age of flying began for me, I was ready to take to the sky in my freshly completed, modified Hummel Bird. No fault of the Hummel Bird design- my plane was grossly overweight, especially with me in it. Takeoff and landing were scary fast. They were correct in saying that no one has ever put a full VW engine in a Hummel Bird and liked it. It is a wonderful plane when built to the plans and with a half VW engine installed, but big people like me just need more airplane.
THE BK1.0
The traditional accessory case casting (that’s used in place of the bellhousing in the car and attaches “ears” to the case) used for installing bushings for attachment to the engine mount is not used in this application. With this new arrangement of driving the prop from the flywheel end, the engine mount is attached to individual fixtures bolted to the otherwise stock VW engine case.
secondary ignition and traditional induction system and we have the complete aircraft conversion. Bob was right, the installation runs so smooth. A bit of a bonus is that it's lighter and less expensive than the traditional Great Plains conversion that uses the standard accessory case. The mount could easily be adapted to almost any firewall, so I expect this will become a very popular style of VW conversion.
HOW IT ALL BEGAN The project really started in 1998. While driving home from work one lazy afternoon, I noticed a Cessna 150 flying overhead. Looking up, I thought to myself, “I used to do that”. I earned my private license in 1969 but four years later, “life” and the high cost of renting airplanes kept me out of the pilot seat for the next 27 years. Then turning 50, I was depressed in a pitiful Peggy Lee “Is that all there is?” moment, sure that flying would never be within my reach again. Then, crazy as it sounds, a faint but clear voice said to me, “Don’t Give Up Your Dreams”. My life was about to change in an incredible way. Back then there were only 96 flight hours recorded in my old, yellowing pilot logbook. Now my third crispy new log book is filled with over 600 hours of flights, with 5 cross-country trips to both AirVenture, Oshkosh and Sun 'n Fun, Lakeland in it, all from my home in San Antonio TX.
With my nose to the grindstone, the first prototype BK1.0 was completed in 2004 and continues to fly today. At super economy nowhere-in-particular-to-go 100 mph cruise, it burns about 2.5 gallons per hour. But, the best feature is NO HOBBS METER! I Like to shoot landings; I usually do 8-10 circuits every time out- I just can’t get enough of the thrill of watching the ground drop away or nailing “the numbers” at every point in the pattern. The plane is a delight to fly. It’s light on the controls, gentle in the stall, and matches Cessna 150 climb performance. I have flown it from my home town of San Antonio, Texas all the way to AirVenture, Oshkosh, Wisconsin (over 1200 miles) on two different occasions and to Sun-NFun, Lakeland, Florida (1100 miles) once. I made each of these destinations in one day with two stops. At times however, the weather seems to change the best of plans. But this led to some of my best experiences- like driving the airport car and staying in airport line shacks. The BK1.0 was built from pencil drawings on notebook dividers, graph paper, and full size poster board templates. Unencumbered by the rigid process of creating CAD drawing and photo documenting (that the BK1.3 plan set offers), I was able to complete the prototype in about 18 months and I knew before it was half done that creating a set of plans from which others could build duplicates would require building a second prototype in order to properly document the process.
Before starting on the BK1, I bought several sets of plans and spent a year and 3 months building a wooden parasol. But one good look at an RV project under construction changed my world; I had to build from aluminum. So I then took the next two years building a highlywww.ContactMagazine.com
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The BK1.3 is that second prototype and was started in early 2005. THE RULE! Build nothing until it is on paper and correct. This requirement is why it took 7 years to build. It’s not that it’s not more complicated than the first plane- I actually found many ways to simplify the entire process. But between the CAD drawings and photo builder’s manual, I spent about 5 to 6 hours on the computer for every hour in the shop. Generally the process starts on the computer with CAD renderings. Draw, then print assembly drawings and templates. Take them to the shop, find it needs more work. Go back to the computer, make any corrections and reprint. Repeat process 3-5 times for a simple part, 8-10 times for a complex part. But once the part is built and fitting properly, that part of the plan set is correct. There are over 300 pages of highly detailed drawings and full-sized templates.
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Step-by-step photo sequences of construction are worth a thousand words of text. Many photos are made with Mister Hands by way of a video camera attached to my forehead, using a mount made from a hard hat.
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Beta Builders: Bill Smith, Bill Batzloff, Glynn Cutchens, Marl Halbrook, Jim Feiney.
Most construction done on folding table-Allows you to keep the car in the garage most of the time.
The camera “sees” what I see, and that’s how I can show both hands in many of the photographs-which would be your same view when doing the operation being detailed. The process involves starting the video recorder, performing the process, checking the video, repeating 2-3 times until it’s just right- then capturing the sequence of stills from the movie. This process is a real time-killer, but it produces exceptional results. Some of my current builders say it is like I am leading them by the hand through the process. The photographic builder’s manual (first draft) has been on my website since 2006. There are over 10,000 photos posted so far, something I never envisioned before starting the process.
BK1 BETA BUILDER PROGRAM After the website photo builder’s manual was started, I began to get requests from future builders who wanted to get started early; something that I thought was a great idea! The Beta Builders have been checking the draw-
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ings and builder’s manual for errors, and making suggestions to improve the BK1 ever since. There are several sets of wings completed, several fuselages done, and much more. These plans are going to be very thoroughly tested by the time of the official release.
TOOLS REQUIRED? 1) Sheet Metal Tools The BK1 requires the same standard set of sheet metal tool used by the most popular kit planes. Several suppliers sell pre-packaged starter kits costing much less than buying them separately. For even less money one could take the list of required tools found on Van’s website to AirVenture or Sun-n-Fun and visit the fly-mart. 2) Power Tools Small band saw, drill press, table sander 4x36/6 in disk, and a 5hp, 20 gallon air compressor with the usual fittings and hoses.
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3) Standard Hand Tools Typical Craftsman mechanics tool set or equivalent.
WHAT DOES IT TAKE TO BE A BK1 BUILDER? Anyone taking on a project of this type would usually have developed basic “shop skills.” It doesn’t seem to matter if you have been working with wood, metal, fiberglass, etc.; all of these require similar skill sets. If you can read, measure, cut, and drill with accuracy you are almost there. Quality of workmanship is very important to an aircraft- it’s not so much a skill as an attitude. 8000 Van’s aircraft prove that many can learn the skills required to produce a beautiful and safe finished product. I prefer hard rivets and am convinced that they are easier and less expensive to use than the blind rivets used on many homebuilt aircraft in this class. But, if you insist, you may certainly use blind rivets to skin the BK1. One last thing learned from this experience; I started my first aircraft project because I wanted to fly. But long before finishing the first project, I already knew that I loved building. The desire to fly will not get one through the challenge and perseverance needed to complete a prowww.ContactMagazine.com
ject, no matter how good the plans are. I think of flying as a great benefit of the build, but I found myself starting the next project within a few months of completing my first plane. It is the best of both worlds; having a plane to fly while building. And it doesn’t get much better than that. It’s my dream that BK fliers will allow me the opportunity to change careers in a year or two. I’d love to go full time supporting the BK1 with pre-made parts, and as previously stated, hopefully growing into full kits, quick-builds, and the like. I’ve already started drawing the next project in CAD and hope to start building the jigs by this fall. It is a very different project from the BK1, designed to be a quick-build from the start. Bruce King bruce@bkfliers.com www.bkfliers.com (210) 363-3288
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C-FLYV By Chris Walterson Geraldton Ontario Canada dkeats@nwconx.net I received my private pilot certificate in 1989 and that same summer I went to AirVenture (OSH) to look at all the airplanes. Fellow Canadian Ted Givens was there displaying his Dragonfly and I was really impressed. On the way home I stopped and bought an issue of Kitplanes
Chris with his direct-drive, turbocharged Subaru-powered Dragonfly MKII, at
and in the classified ad section was a rest in front of his hangar in Geraldton Ontario Canada Task Dragonfly kit being offered, one that was barely started. A week later, after a drive to Atlantic City and back, I had a potential airplane in my garage. I built it pretty much to plans, including the 1835 cc HAPI VW engine up front. Three years later in the late summer of 1992, I made the first flight. I had 140 hours in my logbook, all of which were in a Cessna 150. I had read all I could about the porpoising effect and the various angles of attack and I had also taxied for about ten hours, so the flight went pretty well although the airplane was a little nose-heavy. A repositioned battery cured that problem. I put about 100 hours on it before I decided to fly to the west coast in 1996. I didn’t have a lot of confidence in the VW while trying to climb through the mountain passes. After I got home I read about the success that Reg Clarke had with his direct-drive, turbocharged, intercooled, Subaru EA-81 engine that he installed in his Dragonfly, Expresso (see CONTACT! Magazine issue #31), and that was enough for me to decide that was the way to go. So I ordered his instructional video and started the conversion. I received a lot of help from other builders by joining a Subaru internet chat group- Roger Enns was always quick to respond to any questions I had. Fellow Dragonfly enthusiast, Jon Finley, was also at work installing a Subaru in a Quickie Q-2 at that same time (Quickies and Dragonflys have more in common than not) so we also corresponded. It took over a year to complete the engine conversion and installation, but that wasn’t because it was complicated- but rather it was because I was distracted by the Kitfox on floats I picked up and was flying the heck out of.
Chris’s direct-drive, turbocharged Subaru engine conversion.
Finally the Dragonfly was ready; it flew almost perfectly from the start. I had positioned the radiator in a P-51 scoop under the belly of the cockpit and the CG was spot on. Since then I have put over 350 hours on the engine and have done nothing other than oil changes. It’s been out West once again but mostly I just fly locally in the evening. I cruise at about 150 mph at 3500 rpm and 1 pound of boost. More boost is more power, more speed, but also more fuel. I will use up to 7 lbs boost on takeoff.
Chris’ Kitfox distraction.
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This past winter I decided to try to get a little more horsepower and installed a custom-grind camshaft
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and a front tilting canopy, as opposed to the plans version which hinges from the passenger’s side. The empty weight with the Subaru ended up being 736 pounds (as opposed to the nearly impossibleto-achieve advertised empty weight of 605 lbs). Yes, it’s heavier than the VW version, and a lot more horsepower, but with a gross weight of 1250 pounds, that still leaves me with a useable weight of 514 pounds- better than many light sport aircraft. The engine has a homemade aluminum prop hub, a ring gear from a Ford Taurus automatic transmission, a starter from a Saturn, an Belly scoop, Warp Drive propeller, Mark II gear legs (the Mark I has wheel pants alternator from a Suzuki, and dual built into the canard tips, typical of early Dragonflys and Quickies) and a cowling ignition pickups from a Dodge Colt. that’s suspiciously clear of excessive openings. Sway bar bushings from a Ford pickup are used for motor mounts. The exhaust and intake tubes are mandrel bent exhaust pipe form JC Whitney. The water-cooled turbocharger is from IHI Turbo America (ITA), located in Shelbyville, Il., a wholly owned subsidiary of IHI (Ishikawajima Harima Heavy Industries, Ltd.) of Tokyo, Japan. The carburetor is a 32mm Posa. Yes, a POSA. I have a three-blade Warp Drive propeller and a custom dual-pass aluminum radiator from C&R Racing Inc., located in Indianapolis. I now have a total of 543 hours on the airplane. It doesn’t seem like a lot of time logged in twenty years but with a short flying season here in Canada, and lots of other work to do, I’m happy with that. Once I’m retired, I hope to finish some of my other airplanes and put a lot more hours on the Dragonfly.
Chris’s next project, a Seahawker (Glass Goose) that will be pushed along by a 2.5 liter turbocharged Subaru that uses a G.A.P. Industries reduction drive.
from Delta cams. While it was apart I installed four new pistons and rings, along with all new bearings. The engine truly didn’t need any of this, but for 250 bucks, one can buy all the necessary parts including the gasket set. The entire rebuild job along with the cam and eight new lifters was only $500. Can’t beat that. Some of the features of my Dragonfly that’s a little different from most include pre-molded vortex generators from CCI of Milford New Jersey, elevator gap seals, an aileron reflexor, spring steel landing gear legs (in lieu of the molded fiberglass units offered by Viking back in the day), a removable front hatch that allows easy access to the rudder pedals and brake master cylinders, a removable wing cover (that’s usually molded onto the top of the wing, forming the fuselage section aft of the canopy), www.ContactMagazine.com
Looking out the right side of the cockpit, the panoramic view is only encumbered by the graceful lines of the Dragonfly’s canard, peppered with vortex generators.
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In CONTACT! Magazine issue 103, we featured the gasoline version of Mazda’s new high-efficiency, high-output high-compression SKYACTIVE engine. In this issue we offer some detailed information (straight from Mazda– but edited for CONTACT! readers) on the all-new low-compression, high-output, lightweight SKYACTIVD diesel engine. With a compression ratio of only 14.0:1 the all-new common rail SKYACTIV-D has the same compression ratio as the directinjection gasoline powered SKYACTIV-G. This defies logic and makes it the lowest-compression diesel engine in the world while making it one of the first diesels to comply with strict Euro 6 emission regulations (which don’t take effect until 2014) without needing expensive SCR (selective catalytic reduction) aftertreatment or an LNT (lean NOx trap catalytic converter).
We all know that diesel engines don’t require spark plugs. The injected fuel Higher expansion ratio due to lower compression ratio. mixture ignites on its own at high pressure and the resulting high compression temperature near top dead center (TDC). To ensure reliable cold starting and stable combustion during the warm-up phase, conventional diesel engines have high compression ratios of 16:1 to 18:1. But not Mazda’s unique SKYACTIV-D. Its low 14:1 compression ratio enables combustion timing to be optimized. When the compression ratio is lowered, compression temperature and pressure at TDC decrease. Consequently, ignition takes longer even when fuel is injected near TDC, enabling a better mixture of air and fuel. This alleviates the formation of NOx and soot, since combustion becomes more uniform without localized high-temperature areas and oxygen insufficiencies. Furthermore, injection and combustion close to TDC make a diesel engine highly efficient: The expansion ratio (or amount of actual work done) is greater than in a high-compression diesel engine. Simply put, optimized combustion timing means the SKYACTIV-D makes better use of the energy contained in the fuel. And that is the main reason for the 20% reduction in fuel consumption. See graphs at the bottom of the opposite page. www.ContactMagazine.com
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NO IMITATIONS The fact that Mazda’s SKYACTIV-D is still considered a pilot development today, with no other manufacturer having yet to attempt to emulate it, can be attributed to the system-related drawbacks of low compression. For example, the compression-ignition temperature for cold starts and during cold operation is normally too low in a diesel engine with a compression ratio of only 14:1. It would run rough, particularly in winter conditions, misfiring during the warm-up phase. At extremely low temperatures, the engine might not even start in the first place. So to improve cold starting and cold running, Mazda furnished its SKYACTIV-D with ceramic glow plugs as well as variable exhaust valve lifts.
EXHAUST VARIABLE VALVE LIFT (VVL) The role of the VVL is to allow the internal recirculation of hot exhaust gas into the combustion chamber by using a glow plug to carry out the initial combustion cycle, which is enough to raise the exhaust gas to a sufficient temperature. After the engine starts, the exhaust valve doesn’t close as usual during the intake stroke. Instead, it remains slightly open to allow some exhaust gas to reenter. This increases the air temperature in the combustion chamber, which in turn facilitates the subsequent ignition of the air-fuel mixture and prevents misfiring.
REDUCING WEIGHT AND ENGINE FRICTION The SKYACTIV-D’s lower compression ratio means lower maximum pressure and thus less strain on engine components than what’s produced in conventional diesel engines. As a result, there’s more room for structural modifications in order to reduce weight: Cylinder heads with thinner walls and an integrated exhaust manifold are 6.6 pounds lighter than before, while the cylinder block, now made of aluminum, saves another 55 pounds. And with an additional 25% decrease in the weight of the pistons and crankshaft, Mazda has managed to reduce internal engine friction by 20 percent overall in the SKYACTIV-D relative to the current 2.2 liter Mazda MZR-CD diesel engine.
SKYACTIV-D fuel economy improvement through lower brake specific fuel consumption (BSFC).
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SKYACTIV-D performance improvement by higher torque output at a given rpm.
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Pathway to a Lower Cost LSA? By Jerry Olszewski jerryol@yahoo.com Jerry Olszewski currently sits on the Advisory Board for Innovative Composites Incorporated and works as an independent consultant specializing in composite materials and processes in the automotive and building materials industries. Previously the Vice President of Engineering for Innovative Composites, before moving onto the Advisory Board, Jerry was instrumental in conceptualizing composite modular homes and lightweight shipping containers. With over 31 years working for Chrysler, Jerry is experienced in manufacturing, process engineering, design, vehicle development and program management. His last position held was as a Manager of Applied Materials Technology developing lightweight composite applications using latest material and molding developments, as well as plant resident engineer, design engineer and supervisor, production supervisor, and advanced vehicle engineering manager. Jerry’s most recent 12 years involved research and development of composite material applications, thermoplastic and thermosets, utilizing injection, compression, blow molding and thermoforming processes, in addition to being responsible for the development of alternative body construction for lightweight vehicle design, including applications of composites and light metals, assembly process development, and packaging of advanced power trains such as fuel cell and electric propulsion. Receiving his BS from University of Toledo in Mechanical Engineering, Jerry is licensed as a building contractor in the State of Michigan but most importantly, he’s a private pilot and active in experimental aviation. I am one of those pilots who fly for the sheer enjoyment of flight, relishing the views and freedom of leaving the confines of firm ground. VFR on a clear sunny day, alone or with a single passenger is my typical plan. I would love to have a new plane, but not for the cost of a house. Plus, I don’t need a lot of the features that are standard equipment in typical new aircraft. Even the kits for the homebuilder typically pass six digits, so used aircraft (30 or more years old) were the only reasonable option. www.ContactMagazine.com
Therefore, when the sport pilot rule was announced it appeared that a new aircraft could be in my future. Prices in the $60K range were expected and new aircraft would be right around the corner to satisfy my needs and still take advantage of the latest materials. At the very least some LSA manufacturers would offer an E-LSA kit version, right? With all the advancements in composites, electronics and aerodynamics, surely things would change. Or so we thought. As we all know, some LSAs started out trying to stay below the $100K mark, but today most are well beyond. Much of that is due to powerplants and avionics, but I feel some is due to inefficient processes for the airframe construction. Most of the techniques employed have been around for a long time. For aluminum, bucking rivets and CNC cutting, punching and forming are the norm. For composite, gel-coat, hand lay-up and vacuum bagging is typical, with some prepregs and autoclave. The bottom line is manufacturers use the same methods to build two units as they would for two hundred. I would like to explore the possibility of applying some manufacturing techniques developed in the automotive industry, techniques that were created for the sole purpose of cost-reduction and process improvements. How would kit builders react if they could purchase high quality airframes, constructed using methods a scratch builder couldn’t duplicate, at half the price? The risk is putting up the initial investment that would not be recouped until dozens or hundreds of the models are sold. The task is to develop a good performing and appealing design that can take advantage of these economics. The automotive industry, just like the aircraft industry, has been on the forefront of new manufacturing and material development for the last century. The biggest difference between these two industries is that auto manufacturing is automated with a focus on high volume repeatability that contributes to fewer man-hours and decreased cost. But many processes that have been developed are not practical for high volume production, but may be better for low volume or prototype runs. This means numbers that would equate to full production quantities for aircraft manufacturing.
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The intent of this article is to identify techniques and concepts that could offer lower cost and high quality products to the aviation community. The kit plane manufacturers and homebuilders may be a likely place for these concepts to take hold since these have shown to be the true developers of innovative methods to decrease weight and improve strength and performance.
HISTORY First, some background on the auto industry. Most car models are budgeted for production runs of 100,000 annual volumes or more, with 3 to 5 year production runs. This means that a completed vehicle comes off the line every minute. Operations are broken down into tasks that can be completed in about 50 seconds, with no duplicate operations. The goal is to drive down the piece price and speed up production rates. The trade-off is higher tooling investments with a high degree of automation to obtain cycle times needed for most operations. This is the major strategic difference in the auto and aircraft philosophies. This high investment / low piece-price approach typically results in a stamped sheet metal design for the “body-inwhite” (B-I-W, the assembled automobile body prior to paint application) for several reasons. First, the infrastructure for “metal bending” is well established, with the availability of huge stamping lines, die fabrication and maintenance shops with body and chassis assembly and paint facilities ready to produce. In addition, the durability and reliability is proven, and very complex finite element analysis (FEA) models are finely-tuned for sheet steel designs. This is extremely critical when the development plans for new models are so time sensitive. This forces most material and process development into the advanced research realm. I was lucky to spend several years in this area, as the Manager of Applied Materials Technology at Chrysler, and before that, as an Engineer in Design and Manufacturing at Jeep. For a decade my job was to seek out the best of these new developments and do what the title said, apply them to future vehicle manufacturing programs. Most of my work dealt with light metals and composite materials, with the goal to meet or exceed the volume, investment and costs targets set by the conventional processes. As you might expect exciting ideas were explored that unfortunately wouldn't meet the auto industry requirements for production. Switching from the steel norm was difficult because, to force change, a new idea had to be a cost improvement, weigh less, perform as good or better, and have minimal risk. So a process that met these requirements but would take 4 or 5 minutes to complete could not be considered. However, these same ideas might offer dramatic improvements over the labor intensive methods currently employed in aircraft manufacture. Let’s explore some of these processes as they would apply to both metal aircraft and then composite designs. www.ContactMagazine.com
LIGHT METAL JOINING Lightweight metals for automotive typically mean aluminum or magnesium and are used where the material cost penalty is offset by the need for weight savings. Castings account for a significant portion of their use, in areas where the weight-savings over conventional metals is desired. However, both materials are capable of being used as sheet stock, with aluminum being more ductile and easily formed. Magnesium has been stamped to a certain degree, requiring preheating to prevent splitting. Joining is where the big difference to steel is evident. Aluminum body panels are common since the assembly methods are similar to steel panels. Exposed panels such as fenders are flanged to place attachments behind the exposed surface. Assemblies like doors and hoods utilize hem flanges and adhesives to secure the exposed outer panel to the inner reinforcements, just like their steel counterparts. Adhesive bonding is used extensively in areas where the joint is exposed to a finish surface. Many times this is in conjunction with a mechanical attachment or a hemmed flange to prevent peal propagation in a crash event. Adhesives are also used with spot welding of steel panels to strengthen the joint. It is surprising that this is not more common in aircraft construction since the continuous joint helps to distribute loads more evenly. Jim Bede has used adhesives in place of rivets in his designs for some time with great success.
A robotic adhesive application to a door panel.
However, structural components require a different assembly process. Steel is easily spot-welded, and this is a very cost effective and fast method of joining, but this doesn’t work for aluminum. Pop rivets are used in some areas, but this is considered slow and labor intensive. The typical aircraft method of bucking rivets is not even considered in automotive assembly. One seemingly labor saving process that has been used to some degree in aviation is Friction Stir Welding. This involves the use of a spinning tool that passes over two butted sheets. The spinning action creates friction that warms and softens the aluminum without melting it, then joins the plasticized material via a pin on the rotating head. This is an automated process since the feed rates and pressures are critical factors. The Eclipse Jet uses this process in place of solid rivets, since it offers a ten-
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fold increase in speed, and a continuous seam weld. This is not a process that a homebuilder could use, but if the equipment was available at a builder assist facility it would eliminate hours of riveting and provide a superior surface appearance. Interchangeability with solid rivets or a bond and rivet seam could be a The friction head moves along the two logical step in sheets welding them together. bringing this technology to the kit builder.
Bagging a complex structural part is a risk-filled, intense exercise. When it all works out, the feeling of accomplishment is as much a relief as anything, so it's nice to celebrate a job well done. John McGinnis.
COMPOSITES Composites offer unlimited possible combinations of material and process concepts, with the ability to create flowing compound shapes with structural capabilities not entirely possible with any other medium. Unfortunately, this same abundant number of selections makes it difficult to zero in on the optimal selection for any particular requirement. Usually, a limited selection of resins is used with a variety of reinforcement materials, using layering and fiber direction as the method of obtaining the required structural performance. This usually involves epoxy or vinyl ester resins, fiberglass, Kevlar and carbon fiber cloth for materials, and vacuum bagging with one sided tools as the process.
This is very effective for initial development, but unfortunately the cycle times are always going to be hours per part. The premise of this discussion is to increase production rates from a few a month to several a week, so one option is to build duplicate tools. This increases volume, but does not improve the cost structure. It also introduces part to part variation, which adds to downstream operations. Not to mention the level of operator skill needed to control the molding process methods with countless variables in play as is the case with vacuum bagging technology.
RTM
John McGinnis and his son Kyle slaving away at the production of Synergy, an advanced airframe that will be featuring in the near future. “In the production form of this aircraft, hundreds of these steps are eliminated by relatively low cost investment in molds and equipment. Even so, you would not believe how direct even our 'homebuilders' approach' is, compared to the way many aircraft are still being built today.� John McGinnis.
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One possibility is RTM, or Resin Transfer Molding, which uses a closed two sided tool to mold parts using the same raw materials as vacuum bagging. Recent advances such as VARTM (vacuum-assisted resin transfer molding) and L-RTM (or RTM Light) use lower pressure differentials and therefore
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Cross section of L-RTM mold.
Interior surfaces of show quality is another area where both cost and weight can be saved. The raw surface of laid-up panels (such as the inside of the fuselage) are usually left bare (or coated with Zolatone to disguise the imperfect finish) to save weight and interior volume. But with a smooth surface, add some paint or in-mold coating and now you have an interior trim panel appearance. Textured surfaces can be molded in providing an actual finished surface in combination with inmold gel coats or similar coating applied to the mold surface as the initial step in the molding process.
Since the inside of the part is formed, the design thickness can vary and interior features such as former locations, mounting bosses, and any shape within a few degrees of draft may be included. This becomes very important in subsequent assembly operations. With consistent parts, the sub-assemblies become interchangeable between units, so an assembly line approach to builds becomes possible. With the vac bag method every part requires some adjustments due to the variations in part thickness and every unit is different. Repeatability in the molded parts and the assembly operations is key to taking time, and therefore cost, out of the product.
We have looked at the molded part advantages, now let’s review the process plusses of RTM. The molding time is a one-partper-hour vs. one to two parts per day for open molds, depending on the part size and complexity. One opporRTM test mold. tunity is that reinforcement mats may be formed prior to being placed in the mold. This is done by using a simple forming tool, such as a screen, shaped to the mold. Once the various glass and carbon fiber mats are cut to size and located in the screen, a small amount of adhesive is sprayed on and with a slight compression the preform is “B� staged, or set to an approximate shape of the final part. The downside is that the mats need to be located very accurately so that even distribution of the resin is achieved.
RTM Hood outer panel removed from tool.
Grill panel shows sharp details capable with RTM.
help reduce tooling costs. One main advantage is parts are molded to near net shape with a smooth surface on both sides, with the option of pre-coating the mold with gel coat for a finished part out of the tool. The thickness of the parts is also more consistent, along with the resin percentage as well as total part weight. Another feature is a 300% to 400% increase in production rates per mold versus open molding. JHM Technologies, Inc., has a very good online tutorial available at rtmcomposites.com/demystify.html which illustrates this process very well.
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Cores being added to Pre-form for future attachments.
There are methods of addressing this issue. John Moore of JHM Technologies, Inc., has developed a method of using a silicon membrane for the back side of the part (as in vacuum bagging) yet with the rigid tooling design features of L-RTM created by adding details as hard point locators for features such as ribs, tapping plates or reinforcements. This creates a hybrid process that uses a flexible tool surface where compensation for mat location is required while still offering the advantages of positive feature location. This would allow all components to be placed in the open mold quickly but accurately, taking advantage of both methods of RTM simultaneously.
THERMOPLASTIC SANDWHICHES
When comparing tooling and capital costs, RTM is more expensive than open molding, but the volume increases more than justify them. Capital equipment would be in the range of less than $100k to upgrade from open layup, with L-RTM / RTM tooling running between $200 to $500 per square foot of mold, depending on the tooling complexity and amount of pattern work required. If the intention is to manufacture more than just a few units a month, the numbers start to make sense very quickly.
There’s another option, however. Sandwich panels using thermoplastics are created by heating the core and skin raw stock to 300 to 375 degrees Fahrenheit, then pressing together to a set overall thickness using less than 10 psi, then allowing it to cool to set the shape. This is typically done in a continuous process through a double belt laminator. Until the materials are pressed and cooled they are quite flexible, and forming curves is easy; even slight barrel curves are possible.
Honeycomb thermoplastic sandwich panels.
Many of us are familiar with the advantages of sandwich panels, where a core, typically of foam or a honeycomb matrix, is sandwiched between two layers of a reinforced polymer. The stiffness and strength-to-weight ratio is hard to beat. Most kit manufacturers purchase the material in stock sheets, cut them to shape, then bond the new pieces into position. To make an attachment point for the finished part to join another (such as a canopy or door hinge for example) requires some type of reinforcement or load distribution device to accommodate. But it can only be used in flat applications.
The honeycomb core is flexible until both skin layers are bonded securely.
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To form a skin for a wing panel, for instance, is relatively simple; Heat the materials, place into a two-sided tool, press to shape and allow to cool. Another possibility is to crush the perimeter edge to create a flange to bond to the mating panel, or to form valleys where trimming will be performed. Another neat feature is adding local areas of solid core for mounting bosses and attachments. This is a simple matter of customizing the core with anything from foam to metal, and locating accurately. Appearance skins could be applied in the tool or post applied. The possibilities are vast.
LFI AND PULTRUSION Long Fiber Injection is a fast growing process utilizing polyurethane resin and chopped glass fibers where the finished part has performance approaching that of continuous fibers. In an LFI system, chopped fiber and polyurethane components are combined and delivered to the mold cavity in a continuous process. A microprocessorcontrolled mixing head pulls fiber off a spool into a cutting unit that chops the fibers in lengths up to two inches. Simultaneously, a polyurethane metering machine delivers the polyurethane components to the mix head, where they saturate the chopped glass fibers. A robotic arm directs the mixing head over the mold and sprays the mixture into the bottom of the heated mold. The mold closes and cools and in less than four minutes a completed part emerges.
time and Class A surface quality. However, both require steel tools and large presses, even though the ones required for LFI are much smaller. These processes are mentioned because if the expected product run exceeds several thousand parts, the economics for these processes would be very justifiable. This could be a possibility for certain components that may be used multiple times in each airframe, such as reinforcements. Another available process is pultruding sections using high glass content with urethane or polyester resins. Structural sections for everything from window sashes to I-beams utilize pultrusions, and the potential for spars and stringers is evident.
Pultruded sections.
Again, tooling would cost in the $60k to $100k per section, so with production rates of around two feet per minute there would have to be sufficient requirements to make this affordable. However, if a common spar, longeron, or stringer could be used in various wings or fuselages then this may be a viable option even if it means designing around commercially available profiles. Another possibility is to vary the fibers, such as using carbon in place of glass in the outer flanges for higher bending stiffness versions. This could be done without changing the section and therefore producing different parts in the same tool. Again, this may require higher volumes before being considered.
PUTTING IT ALL TOGETHER Okay, so we’ve looked at several different processes, but how does changing the molding process decrease costs so dramatically? Well, it doesn’t unless the basic design concept is adapted to take advantage of the potentials. Let’s review how a composite LSA concept could evolve. The design must encompass the opportunities before, during, and after the actual molding takes place. Glass fibers on the right are infused with Urethane and blown into mold.
Mold pressures are less than 100 psi, which is low when compared to SMC that requires 1000 psi or more. SMC, or “sheet molding compound,” is the process of choice for automotive because of its one to three minute cycle www.ContactMagazine.com
1) Eliminate as many parts as possible. With two sided tooling, reinforcements may be molded into, or possibly insert molded into the major panel. Formers stiffen the fuselage, but molded in features also increase stiffness, so could the same structure be accomplished without additional parts? Even some-
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thing as vital as a wing spar may be partially incorporated into the upper and lower panels. Take for example a box spar tube where the major structure of the top and bottom could be molded into the upper and lower skins, with the sides being added during the wing assembly. Any elimination of a bonding operation decreases potential failure modes. 2) Simplify the molding process as much as possible by preparing the reinforcement materials as much as possible, “B-staging,” or inserting molded components such as tapping plates and reinforcements to the pre-molding steps. This will utilize the molds to their maximum capacity, increase accuracy of placement, and decrease the post molding steps. 3) The assembly stage is where most of the benefits will be utilized. First, with a consistent back surface of the panel, custom fitting of mating parts will be minimized, and the installation of these parts will be faster and more repeatable. Mounting features like tongue and grooves and locating tabs will aid positioning and eliminate the need for locating fixtures. Since these operations are often performed by the homebuilder it would eliminate many of the time consuming operations at this stage and at the same time provide a consistent final product.
COMPROMISES So now we’ve taken some time and complexity out of the equation, but how do these design modifications affect the finished product? There is always a balance between material costs, tool costs, processing time, and product performance. We all know the inherent design differ-
ences between tube and fabric, metal, and composite airframes. The design for an LSA model is not going to have the same requirements as a pressurized turbine powered speedster. Remember, the premise of this discussion is to make a lower cost, easier to build LSA for the sport pilot, so there will undoubtedly be some compromises. We accepted exposed rivets for aluminum, seams and stitches for fabric coverings, and some waviness in foam core composite models. Maybe some readthru distortion or visible seam lines will be just as reasonable for the next generation of low cost concepts. A functional design has a beauty of its own when it works well. The key to this evolution is to design the concept using the appropriate materials with the optimum process, or combination of processes, to obtain the most efficient overall product. Over-molding and insert-molding are preferred over a secondary adhesive operation, and smart designs that consolidate components and decrease complexity are required. Utilizing proven processes with experienced experts from various backgrounds will go a long way.
CONCLUSION The question is, will “If you build it, they will come” hold true for an aircraft design that offers better performance for less cost, in the quantities required to justify higher initial investment? This could be the way to get the affordable Light Sport model we’ve been waiting for. And there are dozens of other material and process possibilities out there just waiting to be tried. Any takers?
SKYACTIVE-D Engine from Mazda – continued from page 13 TWO-STAGE TURBOCHARGER
Turbochargers not only help diesel engines deliver good low rpm torque, but also help to improve fuel economy while reducing harmful emissions. The SKYACTIV-D uses two-stage turbocharging- one small and one large turbocharger, which are selectively operated according to driving conditions. The small, quick-responding turbo feeds air to the combustion chambers at low engine speeds to provide low-speed torque and eliminate “turbo lag,” which is characterized by abnormally low torque and poor throttle response. It’s caused by a lack of sufficient exhaust pressure to rotate the turbocharger’s turbine up to the speed necessary to supply the required boost pressure. Together, the two turbos ensure high torque and responsiveness at low engine speeds and high power even at unusually high rpms, enabling the SKYACTIV-D to easily reach its 5,200 rpm redline. There is no compromise to power, driving dynamics or driving enjoyment, despite the engine’s extraordinary efficiency. And the synergistic effect of the two-stage turbocharging and low compression ratio enables optimal timing for combustion. Since there is a sufficient supply of air (oxygen), NOx and soot emissions are kept to a minimum. Most of the issues solved by the two-stage turbo aren’t an issue in an aircraft application, and some further experimentation with turbochargers might reduce some of the complexity and weight of this system. www.ContactMagazine.com
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By Oscar Zuniga Ed Fisher was inducted into the EAA Homebuilders Hall of Fame in 2011 and deservedly so. He is a prolific designer, innovator, and homebuilder, and he continues to produce designs that are responsive to changes in the way we fly and build. But he infuses classic lines and appealing touches into his designs that keep them from being too trendy or oddlooking. In the last year, Ed and his wife, Val, have made some decisions that promise to keep Ed and his Raceair Designs true to their roots, and some of those decisions were made because of what Ed was hearing from homebuilders. Ed’s plane Lil’ Bitts was featured in CONTACT! Magazine issue 92 (Jan-Feb 2008) and Ed is now finally ready to bring it to market. Ed plans to have a booth at EAA AirVenture Oshkosh 2012 and will be bringing the plans-built Skylite and Lil’ Bitts to the event. He is working diligently to translate the design for Lil’ Bitts to plans and construction manuals that will be available to builders this year. When Ed designed the clever little biplane and then successfully flew the prototype, he intended to produce it in kit form for the experimental light-sport market. However, feedback from builders steered him away from that plan back to just offering the plans and letting builders assemble their own materials for the airplane.
From Lincoln Logs to Bisquick, there are some things that appeal to people who just want to make things themselves. And apparently there is still a strong market for plans-built experimental aircraft; Raceair is committed to that market, and Ed has proven that he knows what builders and pilots like. With popular designs like the Skylite, Zippy Sport, Micro Mong, Flitplane, Zipster, and now Lil’ Bitts, builders will continue to have a good selection of light-sport configurations available, and all can be built using modern designs, materials, and methods while still retaining flight characteristics and visual appeal that are proven and pleasing. The plans/manual package for Lil’ Bitts are now available and are currently being sold. Go see Ed at the Raceair Designs booth at AirVenture 2012 and pick up a set! His website is www.RaceairDesigns.com Ed Fisher 361 Whiteplains Place Gilbert, SC 29054 Telephone: 330-518-8383
Raceair Designs Lil’ Bitts Wing span
19'-4"
Wing area
112 sqft
Fuselage length Height
15' 5'-7"
Empty weight
432 lbs
Gross weight
800 lbs
Useful load
368 lbs
Wing loading Take-off roll Climb
7.1 lbs/sq ft 300’ 1,700 fpm
Cruise
95 mph indicated
Stall speed
39 mph indicated
Top speed
109 mph indicated
Stress Fuel capacity
+ 6 and -3 G 12 US gallons
Photo: William Wynne
Before Lil’ Bitts, Ed’s Zipster ultralight biplane, a steel tube and rag, aluminum wing structure aircraft which weighs in at a FAR 103 ultralight legal 254 pounds, won the 2004 Gold Lindy Ultralight Grand Champion award. Ed Fisher comes from an oldschool EAA family, and he's been designing light aircraft since 1980. Among others, he designed the Zippy Sport, Micro Mong, and the Skylite. The Skylite won Grand Champion Ultralight honors when it debuted at AirVenture in 1991.
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By Michael C. “Mick” Myal Mick Myal graduated from the General Motors Institute in 1953 with a BachePhoto: Karl Walter lor of Mechanical Engineering degree and is a U.S. Army veteran. His 35 A two-place Cavalier experimental homebuilt using Cessna-style tip tanks years at GM included assignments in body production and styling among other tasks. An WHY TIP TANKS? EAA member since 1959, his aviation hobby includes Let’s argue the advantages of tip tanks. Replacing inconsulting on two-engine STCs, the building of a wing tanks with containers at the wingtips should require Minicab, a 2/3 Mustang, and a VariEze. He’s the auless homebuilder hours. Consider the extra effort needed thor of several Sport Aviation articles, three Alternato seal wing structures and the time needed for repair. tive Engines books for homebuilt aircraft, and is the Roll stability can be expected to be better. (Picture the founding publisher of CONTACT! Magazine. circus high-wire act.) Placing fuel away from the cockpit is always a good idea. I must confess. I’m a believer in tip tanks. As an EAA member since 1959, I saw the adaptation by homebuildMy mission was clear; reintroduce tip tanks to the movement. My initial plan was to piece together a story on ers of this World War II technology during the 1970s. how to build a tip tank plug. The goal of the story would Larry Burton’s cool-looking Cavalier won the 1st of Class – All Wood Construction award at the EAA annual conbe an attempt to convince designers and builders that the process was indeed simple and inexpensive. At that vention in 1975. Joe Alvarez came in with the Pollipoint the article’s impact seemed weak; there wasn’t wagen, an advanced composite two-place design with a pollywog-shaped fuselage. And Pazmany’s all-metal enough meat to make my point clear. And that tale was already told many times over, like those that tell of the creations rounded out the application to wood, plastic, production of a fiberglass engine cowling. My focus and metal, respectively. changed from a boring how-to article to providing actual patterns and hardware references. So I decided to write Then came the canard craze preaching a “quick build,” and publish a book. which left little market room for conventional designs. Nevertheless, metal workers had their say about “compost” airplanes. Canards and tip tanks as factors in IDEAS JUST HAPPEN CG management didn’t mix then and never will. In my case, publishing full-size patterns as a means of inducing people to take a close look at the tip tank has I concluded that tip tank technology was a dying design other advantages. The book format I chose is unconvenfeature, overcome by numerical success of the RV series tional; pages are legal sized (11 inches wide by 8-1/2 and many of the new composite offerings. Why would a inches tall) which produces a booklet fitting nicely in U.S. designer want to incorporate this feature and add comPostal Service flat-rate envelopes. At this early stage it’s plexity to his design when it’s not being demanded by too early to know if my work will generate a fresh interest homebuilders? in tip tanks. I’m proud of the end product, but time will tell if my mission was successful. WHAT MAKES A TANK A TIP TANK? Essentially, it must be a sealed container at certain times and its contents accessible on demand at other times. It must be located in close proximity to the longitudinal CG of the airplane so that flight balance is ensured at all times. That location falls approximately at the 25 percent of the design mean aerodynamic chord (MAC).
A view of the cover of Mick Myal’s new tip tank book.
I consider tank hardware to be a duplicate of existing conventional tank systems and leave the selection to the builder. A large variety of filler caps, fuel senders, vents, strainers, quick drains, and other related items are available from supply houses, and almost any one of them
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SWITCH ON! Continued from page 2
can be made to work. Installation of these parts should follow standard practice as ably covered in the Tony Bingelis books. If a builder is at the point of beginning wing construction, it’s time to study the plan drawings for these called-out parts and the specified fuel lines. The volume of the tip tank is a key variable and needs to be addressed early in the process. My project tank was based on eyeball measurements of a Beechcraft Bonanza 15-gallon tank. Since I felt this tank shape had an elliptical look, I estimated the major axis at the tallest point to be about 13 inches and its minor axis to be 8 inches. The tank chord or length was about 72 inches. To contain the shape, I decided on utilizing the shape of a circle segment. I found an obscure formula that provided the essential data points:
R = (4 x T2 + C2) / (8 x T) where T = template and C = chord Two radii controlling the major and minor design lines were inputted into a CAD program to produce the spreadsheet published in the booklet. Our first showing at COPPERSTATE 2011 was a hit. One customer went home and devised an automated version of the original spreadsheet illustration shown on page 9 of the book. You’ll save a lot of time using this tool. It’s free for downloading at www.ContactMagazine.com/TipTanks The rest of my work was the CAD drafting of full-size patterns that were used to produce the male plug in the photos in the book, the female mold, and tank shells. The use of a water jet was investigated as a time/money tradeoff option for cutting the form bulkheads. One caveat: Seek the finest orifice to minimize the effect of cut growth taper. I forgot my earlier experience and nested duplicate parts. Guess what—the bottom piece was smaller than the top. Other than locating the tank midpoint at 25 percent of tip chord, not much more can be suggested for structural attachment. Simply put, each type of wing construction (wood, composite, metal) will have its unique subsets of differing structure arrangements. A simple load diagram can be drawn to show the tank load moments acting on the tip spar. Attachments will be in shear, the number dependent on materials, techniques, or both. Fittings such as seatbelt restraints are stressed to 9g. I would use that number. I trust this narrative will prompt designers and kit manufacturers to consider and evaluate the merits of tip tanks as a viable alternative or addition. Homebuilders, too, can find this tank an intriguing possibility. Feel free to contact me at mick22@cox.net with any questions you might have, or visit my website at www.tiptankplans.com
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EAA and SAA member and has worked out details with Paul over the last several months. The organization is now seeking to rebuild the membership base. Fisher said, "We think it’s the right time to fire up the SAA. We want to recreate the organization to provide a home for the grass roots aircraft builder, restorer, and pilot– the little guy in aviation." The first membership term runs from June 1st, 2012, thru December 31st, 2013, so members will enjoy a full 18 months of membership. Initially newsletter derived, plans are in motion to return to a full magazine format with three issues of To Fly being published each year. Ed's speaking engagements include the Frasca Fly-In, Urbana Illinois, on June 23rd, and the Brodhead Pietenpol gathering on July 21st. Something informal will follow at Oshkosh, where Ed's company, Raceair Designs, has booth #619, and with a couple forums on “traditional homebuilding.” It’s certain that the SAA will be in the conversations. SAA does not employ a defined membership dues fee, but is a donation-based organization at this time. Although said donations are not tax deductible at this time, they are truly appreciated. For more information or to make a contribution, contact Ed Fisher at raceairdesigns@hotmail.com Make checks payable to Sport Aviation Association, and mail to 361 Whiteplains Place, Gilbert, S.C. 29054
FACEBOOK I’d like to remind everyone that CONTACT! Magazine has a Facebook page that is updated nearly daily with news and information that we find to be important or otherwise informational to homebuilders, even if it’s just fun and unusual images of videos. It’s of course free to visit– with nothing to join or otherwise collect your personal information, but if you are already a Facebook users, you might like to “like” us. www.facebook.com/www.CONTACTMagazine
DIGITAL VERSIONS of CONTACT! Magazine We’ve been testing a digital version of CONTACT! Magazine for several months now, and people seem to like it. I still don’t have a secure way to distribute it so that subscribers can’t send it to all their buddies for free– which wouldn’t be such a bad thing if we had advertisers who pay the bills and can benefit from the additional distribution network, but Continued on page 24
CONTACT! ISSUE 104 PAGE 23
Classified ads– minimum $15 donation from subscribers. All ads must include a price. No commercial ads allowed. Ads will run for 3 consecutive issues or until sold. Must be renewed after the 3rd printing. CONTACT! Magazine reserves the right to refuse any ad. FOR SALE: Miscellaneous parts. One of our supporters donated the contents of his garage. Listed below is a smattering of what we have available, and the value we declared for his donation. No reasonable offer will be refused. Please contact Pat Panzera with your questions or offer. CONTACT! Magazine, 559-584-3306 panzera@sti.net Subaru 2.0 engine, extra head REDUCED MORE New Mazda A10 engine Brock master brake cylinders Vari-Eze Vari-Eze spinner SOLD! Dragonfly project, no engine Dragonfly project, no engine Dragonfly project, ready to taxi
$650 $600 $308 $150 $1,500 $5,000 $9,500
DONATE YOUR PLANE, PARTS OR PLANS: The first ever “for aviators by aviators” charity needs your support. Receive tax benefits for a charitable contribution, donating your plane or any of your surplus parts and/or materials. See page 22 of CONTACT! issue #72 or visit ContactMagazine.com for information on our 501 (c)(3) charity. CONTACT! Magazine (559) 584-3306
For Sale: B0208/MFI-9 (Messerschmitt built) A unique recreation of the mini-coin Biafra Baby #BB905. Historically accurate and documented. New zero-time TMX IO-240. A highly maneuverable small ship for a small pilot. Registered Experimental/Exhibition warbird. New prop, paint, interior, instruments, wheels and brakes. NOT LSA qualified. Contact italmotion1@comcasr.net for brochure or go to www.italmotion.com for images under “current project.” Priced at $38k FL59 Ft. Myers FL. Partial or full trades for aircraft or vintage racecar considered. Don Black 107 For Sale: Instruments- Falcon GH-002 3 1/8" Vacuum Attitude Gyro ACS 10-22955 $250 * Airborne 1J7-1/D9-18-1 Filter ACS $25 * 4" Venturi ACS 15050 $35 (has fiberglass streamlined housing) These units have about 300 hours total.* CONTACT! Magazine (559) 584-3306 Sales@ContactMagazine.com 103 For Sale: Subaru EJ-22 Firewall Forward. 300 hours TT w/o any problems. Ross redrive, all electronics, engine mount and some spare Subaru parts included. See CONTACT! issues #6 and #8 for a full description of this engine as installed on a Dragonfly. $5,000 Ruidoso NM. Randy (575) 937-3586 lsbp1919@yahoo.com 102 For Sale: Two RV6 Motor mounts for 4.3L Chevrolet V-6. One tail dragger, one with nose wheel. $1,000 each. Ruidoso NM. Randy (575) 937-3586 lsbp1919@yahoo.com 102
Wanted: Tuned port fuel injection system for my Ford Windsor 351W (See CONTACT! issue 16) which would be fed by my McCulloch (Paxton) supercharger, with each cylinder's injector adjustable and all mixture leanable. For Sale: Prince P-tip propeller with Gates 2.67:1 PSRU and Polychain Kevlar belts, Used 40+ hours on O'Neill Magnum V8 “Pickup” with modified Ford 351W, with and without McCulloch (Paxton) supercharger, 260 to 380 HP. Spinner included. Engine not included. $800 For Sale: Torsional vib. damper, for Lyc O-320. $180 For Sale: Female molds for wingtips for NACA 4412 airfoil, 63" chord. $170. troneill@charter.net Terrence O'Neill 103
ALTERNATIVE ENGINES VOLUME 3 The third in the series from Mick Myal is available only through CONTACT! Magazine. See the back inside cover wrap of this issue for ordering info or visit www.ContactMagazine.com For Sale: 3.8L Ford V6 with Blanton redrive, as pulled from an RV-6 shown on Youtube.com by searching for “V-6 airplane engine” (yellow plane). Includes three-blade Warp Drive prop, all manuals and engine instruments. $2,000.00 Buyer pays shipping from Benbrook TX. (817)692-6742 Richard luggman@sbcglobal.net 102
ALTERNATIVE ENGINES VOLUME 2 Once again available! See the back inside cover wrap of this issue for ordering info or visit www.ContactMagazine.com For Sale: Glasair 1 TD kit. Fairly complete, unstarted kit with extras. $4500.00 Located in Hanford California. Please contact Pat Panzera with your questions or offer. CONTACT! Magazine, 559-584-3306 Sales@ContactMagazine.com 106 For Sale: Ross Redrive with aluminum flywheel. $1800.00 For Sale: Warp Drive Propeller threeblade, 66” diameter, left-hand rotation with nickel leading edges. Comes with spinner. $500.00 Or buy both for $2000 total. These components were bolted to a Subaru EA-81 and tested for a maximum of 30 minutes only. Buyer pays shipping from Las Vegas NV 89104. Don Thompson (702) 236-1691 106
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Alternative Engines Volume 4 CONTACT! Magazine currently offers three 8-1/2x11 soft cover books, each of them a unique, authoritative reference, dealing with auto engine conversions, each unrivaled in scope and detail of content. Each volume of "ALTERNATIVE ENGINES" is a compiled work of past CONTACT! Magazine articles, documenting individual experiences in preparing, installing and flying converted auto engines. The three volumes also contain important information and solutions for cooling, ignition redundancy and selection of components. We are pleased to announce the publication of yet a fourth in the series, "ALTERNATIVE ENGINES VOLUME 4" Over 350 glossy pages of black and white content, (or your choice of full color!) compiled from issues of CONTACT! Magazine (picking up where Volume 3 left off) as published by Patrick Panzera, the current editor and publisher of CONTACT! Magazine. Each volume explores in detail the builder's or designer's trials and tribulations in development and testing. Decades of experience are available at your fingertips, presented in a manner that is educational, informative, and entertaining. While we have not printed the book yet, progress is being made. We are very close to being ready to go to print, but we need your help to make the color book happen. While the black-and-white version will be created on a "print on demand" basis, we have to preorder the color book in in the highest quantity possible in order to get the best price. The prices shown below are based on a first run of 500 books, and that's where we need your help. Just as we did with Volume 3, we are asking you to pre-purchase the book now, which is several months before they actually become available. We will either have enough orders in the next few months to go into print, or we'll refund all the monies sent in for the color book. The black-and-white version will go to the printers in two months no matter how many orders we get.
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