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Thread: New to Aviation, Starting a Homebuilt Project, I'm in need of prefessional opinions.

  1. #1

    New to Aviation, Starting a Homebuilt Project, I'm in need of prefessional opinions.

    I'm an experianced automotive/Heavy duty Diesel Technician, familiar with almost anything mechanical. However I'm new to aviation and composite materials. And I would appreciate some direction from experianced aviation enthusist.

    I'm looking for a small plans built plane that I can mostly build in my garage, with my son. So that needs to fit 2.

    I've been looking into the Rand Robinson KR-2. It seems to meet my needs and it's specs are appealing to me.
    Does anyone have experiance with this aircraft?
    I like the idea of the Corvair engine, and low cost and it's fuel economony makes it affordable.

    I'm considering constructing it from all composites using a PVC Divinycell foam core, fiberglass, and epoxy resin.
    I've been trying to find recommended procedure for using the PVC foam core but havent found one. Anybody have experience here?
    Should I be vacume bagging components?

    A guy has been constructing one www.krsuper2.com. Can anyone tell me if his design and building techniques are legitiment?
    I'd like to follow his direction. I like the modern version of the KR-2.

    Any information about these is appreciated.
    Last edited by jasontuntland; 07-04-2012 at 05:30 PM.

  2. #2

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    Quote Originally Posted by jasontuntland View Post
    A guy has been constructing one www.krsuper2.com. Can anyone tell me if his design and building techniques are legitiment?
    I'd like to follow his direction. I like the modern version of the KR-2.

    Any information about these is appreciated.

    You'd have to contact him......I'd say his mods are substantial enough that he should abandon any reference to KR-2. 33% gross wt increase is a serious change, not to be taken lightly (no pun intended, LOL).

    There's tons of information on the internet. You can also check out Mark Langford's modified KR-2S with different airfoils and Corvair engine. I believe the plane was distroyed after the third crankshaft failure but his website is still running.

    Otherwise, bulding the KR-2 is pretty straightforward. I think you'd like the building process, it's not difficult. Also consider while the final product will be okay as long as your son is small. He's gonna grow up and it's tough to cram two full size people in a KR. Ken Rand was a little guy. KR-2 builders have an annual gatherering....it's worth going to. Those guys have a great time.

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    I'm not very familiar with the KR-2, but I thought that it's a metal plane, no? If so and you want to do it in composites, you're designing an entirely new plane, however much it looks like a KR-2. As such, you need to have the skills to design and analyze the design.

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    The KR-1 and 2 are actually wood airplanes (spruce and plywood). But with foam and fiberglass to give the slick shape, otherwise not possible with just plywood. Some use molded parts. But the load bearing parts such as spars and other structure, is wood.

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    Quote Originally Posted by Dana View Post
    I'm not very familiar with the KR-2, but I thought that it's a metal plane, no?
    Nope. Wood with built up foam and glassfiber skin.

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    steveinindy's Avatar
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    I believe the plane was distroyed after the third crankshaft failure but his website is still running
    What was up with his choice of crankshafts that caused him to have three of them fail? Was it a quality control issue, the way the engines were being maintained, how they were being run?

    He's gonna grow up and it's tough to cram two full size people in a KR.
    That was going to be my other point about the KRs. I'm 5'9" and 165 lbs and it's an uneasy fit for someone my size when you have another person in there with you. It's a great little plane but it's not something you really want to have if you're intending on running any great distance with an adult sized passenger. One of my now deceased friends used to own one and he joked the only time he got intimate with his wife anymore (both being in their 60s) was when they would fly together.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  7. #7
    Quote Originally Posted by martymayes View Post
    You'd have to contact him......I'd say his mods are substantial enough that he should abandon any reference to KR-2. 33% gross wt increase is a serious change, not to be taken lightly (no pun intended, LOL).

    There's tons of information on the internet. You can also check out Mark Langford's modified KR-2S with different airfoils and Corvair engine. I believe the plane was distroyed after the third crankshaft failure but his website is still running.

    Otherwise, bulding the KR-2 is pretty straightforward. I think you'd like the building process, it's not difficult. Also consider while the final product will be okay as long as your son is small. He's gonna grow up and it's tough to cram two full size people in a KR. Ken Rand was a little guy. KR-2 builders have an annual gatherering....it's worth going to. Those guys have a great time.
    You know, I had overlooked that weight factor. How did I do that.
    I had come across this updated airfoil and planned on using it.
    Can I easily aquire the wood nessary to build something like this? IE Lowes, or will i be freight shipping lumber from AircraftSpruce.com ?
    I am 5'10 200lbs and my son is only 12 but I want It to be comfortable enough for long trips.
    Any suggestions on simular aircraft that might be more spacious with simular stats?

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    Quote Originally Posted by steveinindy View Post
    What was up with his choice of crankshafts that caused him to have three of them fail? Was it a quality control issue, the way the engines were being maintained, how they were being run?
    Not all that uncommon in the converted auto powerplant arena. Bolt an unsupported extension with prop on the end of the crank and you get bending fatigue failures as the stock corvair crank was not designed for that type load. A popular corvair mod is a 5th bearing for extra support but I'm not convinced that is "the" solution.

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    Quote Originally Posted by jasontuntland View Post
    Any suggestions on simular aircraft that might be more spacious with simular stats?
    There's tons of two place airplanes, each has it's strength and weaknesses. You just have to study them all and find one that fits your needs. You may prefer one type of construction over another so that may influence your choice. Don't get overly concerned with some of the published performance numbers, particularly top speed. Many times these are not realistic.

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    steveinindy's Avatar
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    Bolt an unsupported extension with prop on the end of the crank and you get bending fatigue failures as the stock corvair crank was not designed for that type load.
    That's what I figured was going on but I have zero experience with converted engines and so I asked to be sure.

    A popular corvair mod is a 5th bearing for extra support but I'm not convinced that is "the" solution.
    Does it work to significantly reduce the rate of crankshaft failures? I'm a big believer in the KISS method when it comes to engines. That is, the less I have to do to it for it to work well with minimal problems, the better. Then again, that largely stems from anything firewall forward being a nebulous gray area to me.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



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