Building/finishing, and hopefully flying a homebuilt aircraft...
That should someday look something like:
But for now, it looks like this:
I'm Cedric Hughes.
By the time I finish my KR-2S I'll be old enough to solo it!
This website will be as much about becoming a pilot, as it is about building the airplane I plan to fly.
I'm pretty new to all this and really need your helpful suggestions/advice. Please send them via the contact page. Or come to one of the Experimental Aircraft Association (EAA) chapters I belong to:
EAA Chapter 52 Sacramento CA - http://www.52.eaachapter.org
EAA Chapter 1230 Vacaville CA - http://www.solanopilots.com
My Airplane Story
After emigrating from Ireland to Canada, my great-grandfather began as a garage mechanic. To manage transport in the powdery snow of Northern Canada, he used to build snow-planes. Much like the airboats, snow-planes use an aircraft propeller rather than wheels or tracks (tracks bog down in the light deep snow).
(You can click on most of the pictures for a larger image!)
My grandfather Gary Hughes was a pilot. After being a "flying doc" servicing remote communities in northern Canada, he smartend up and moved to California. He flew a Piper 180 until SMOG in California made it nearly impossible to fly VFR (by Visual Flight Rules) many days.
In the second picture above, notice the SMOG obscured mountains around San Jose CA. Thanks to Jerry Brown and catalytic converters California's skies are clear and flyable again. We still manufacture cars - but they're electric.
(Go Tesla!)
My dad's first homebuilt airplane - an Osprey II:
Pretty cool, but now he flies a minivan:
You might notice the sleeping bags next to the plane. One of my father's favorite ways of torturing me is to fly to some remote place and camp under the wing of the plane. Sounds good, but I think in practice a high wing airplane would work out better...
Anyways, it's a nice plane and very exciting to fly:
My KR-2S Adventure Begins!
I found a nearby partially built airplane project for sale on Craigslist that looked great and was affordable. It was a partially built KR-2S, which is the stretch version of the two seat KR-2 airplane. The KR-I was first brought to Oshkosh in 1972. In 1973 Ken Rand and Stuart Robinson, designed and built a two place version - the KR-2.
My "new to me" airplane project will be an early KR-2S (Serial #3823)- when the "fix" of stretching the fuselage was being used to overcome pitch sensitivity of the KR-2, but before Mark Langford integrated the NLF(1)0115 airfoil as the new standard replacing the RAF48 that is used on my plane (http://www.krnet.org/as504x/).
The first builder of the KR-2S I was looking at was Richard M Dowler. Sadly, Mr. Dowler "flew west" some time ago. His daughter was selling the project, but she didn't know much about it. Figuring out what Mr. Dowler built, what design and build decisions he made and why, will take some detective work. My dad says its often harder to start a project in the middle than it is to start from scratch. We went to look at it and ended up bringing it home.
Good advice will be crucial to identifying problems and potential solutions on this airplane. For example, issues dealing with the engine. VW engines were not designed for airplane use. Figuring out how to safely and successfully use them on airplanes is exactly what collective knowledge and experience is all about.
There is an internet community of KR aircraft builders and fliers:
Another topic specific user group that should be a great source of interactive information is the VW Conversions Yahoo group:
Interesting KR-2 Information:
Ken Rand designed the KR-1 in 1972 making it one of the first airplanes made with the now standard foam-and-fiberglass composite construction method. Two Mechanical Engineer's Master's Theses on the airworthiness of the KR-2:
https://ae.sjsu.edu/files/public/nikos/MSAE/pdf/Bravo.F11.pdf
https://ae.sjsu.edu/files/public/nikos/MSAE/pdf/Nordin.F06.pdf
Flight Information Manual by Serge Vidal for a VW powered KR-2:
http://krbuilder.org/Documents/POH%20Serge%20Vidal.doc
Flight Information Manual by Dan Heath for a VW powered KR-2:
http://krbuilder.org/Documents/N64KR%20Flight%20Information%20Manual.doc
Great Plains aircraft VW Engines:
http://www.greatplainsas.com/cat2014I1.pdf
HAPI Engine AD:
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What I'm Beginning With - Possible Problems and Potential Fixes:
After trying to learn about the VW aircraft engines, KR-2 Airplanes, their history, and the experiences KR-2 builders and pilots have had, I have been able both identify what I have, and to put to put together a list of "possible problems and potential fixes" for my airplane. Figuring out reliability issues is demanding for homebuilt/experimental aircraft since there is no one-approved-way to do things. Additionally, no organized record is kept of what doesn't work / goes wrong (as the FAA does for certified aircraft). No doubt this is just the beginning of "figuring out" my KR-2, but here's what I've learned :
Instrument Pannel:
The project came with a basic instrument panel including an old com (voice communications radio) and transponder (to let air traffic control know where you are). I may have to update both since neither conforms to current Air Traffic Control requirements. Additionally, integrated electronic instrumentation often weighs less, and can alert the pilot to the relevant information in case of trouble.
Propeller:
The plane came with 2 propellers: 1) A Sterba (54 inch diameter x 52 inch pitch) propeller, 2) a Great American Propeller (52 inch diameter x 56 inch pitch). Getting the best diameter and pitch propeller can be costly process of trial and error - especially since the VW crank isn't compatible with adjustable pitch composite propellers. You guess based on expected performance of your airplane and modify based on observed full throttle RPM of you current set up (too high RPM, greater pitch needed). Perhaps Mr. Dowler bought the Sterba as a "cruise" prop and the Great American as a "climb" prop, or perhaps one just became "available" through a friend. I'll wait until we see what we get out of the Sterba 54x52 before I worry too much more about it.
The 54x52 Sterba Propeller:
The 52x46 Great American Propeller:
VW Engine:
The air-cooled VW Bug engine has a long and mixed history of conversion to aircraft application.
The plane came with a HAPI 75 Magnum engine - which is a conversion of a VW bug engine to an aircraft engine. HAPI went out of business in 1989. The Magnum 75's (94mm pistons with a 69mm stoke for 1914cc's) and 85's (94mm piston with a 78mm stroke for 2165cc's) using on Scat's Split cylinder heads were HAPI's last products. Experience since has shown they have many reliability issues:
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SCAT VW Heads:
Crank Shaft / Prop Hub:
Propeller Extension:
The HAPI Magnum VWengine is fitted with a propeller extension (black bit between prop and rusty prop hub in the photo below). It helps makes the profile of the front of the plane more aerodynamic and sleek, but we are starting to get some advice that they also increase stresses on the engine - something the VW might not be able to take.
Revmaster has a pretty good summary of issues with the crank and their fix: Revmaster Crank Study
We may install a the Revmaster Crank.
HAPI Alternator / Flywheel :
The HAPI engine also has a problem with the fly wheel (stator wheel) cracking.
Dual Electronic Ignition:
The engine was set up with dual Capacitance DischargeI Ignition (CDI) timed/triggered off a modified vacuum advance distributor. Failure of electrical power = dead engine. Additionally, the vacuum advance distributor sticks up from the engine requiring a substantial bump added to the engine cowling to fit it in.
Mr. Dowler mounted the secondary ignition coils on the front of the engine on top of the oil pump. I don't know why, perhaps to keep them cool? Oddly, we can see that the front set of ignition coils (green) were at one point also mounted on the firewall (close to where the gascolator is now). Perhaps Mr. Dowler moved them from the firewall to get them away from gas (spark and gas not a good mix except inside the engine) or had to move them to make room for the change from the POSA carburetor to the Lectron carb.
Lectron Carburetor:
Mr. Dowler first mounted a POSA carb and then replaced POSA carb with a Lectron float carb that has in-flight mixture control. It looks pretty good but I know little about the Lectron Carb. The Lectron carbs have a great reputation in the dirt-biking community - but are almost unknown to the homebuilt aircraft community.Most everyone agrees that the Ellison carb is a reliable and trouble free carb solution for the VW.
Wing Tips:
I've been trying to figure out what the effect of the "Modified" Hoerner wing tip may have on my KR's aerodynamics. By reducing wingtip vortices, Hoerner wingtip's are known to have a number of advantages including decreased drag and increased lateral stability. But the wingtips on my KR start square, then fillet back into a Hoerner shape. Perhaps the original builder may have intended to place wingtip lights on the outer flat space? Whatever the reasoning, the fillet and transition behind the leading edge is quite dramatic a worrisome to my eye:
Wing Skins:
The KR-2S wings are built using wood spars and ribs, then filled/shaped between the ribs with foam, and finally covered with fiberglass. Our wings seem mostly well built, however my father found some small areas of de-lamination (separation of the fiberglass skin from the foam). De-lamination is generally a very bad thing in composite construction since it is the basis of most structural failures. One mitigating factor is that the skin on the KR-2 wing isn't "structural" (forces are mostly carried by the wing spare. Even so, I will have to fix the de-lamination by either cutting out and replacing the affected areas, or if the are small enough, injecting epoxy under the skin, and then vacuum forming the skin back down onto the foam. Here are two pictures of the wing being made:
Fix? I'll probably do nothing immediately, but will plan on bolt on wing tip extensions that have the advantage of optionally increasing wingspan.
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