New member from Dayton Ohio area.

Discussion in 'New Member Introductions' started by Chris Matheny, Nov 27, 2019.

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  1. Nov 27, 2019 #1

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    Hello all, I'm Chris Matheny from near the birthplace of aviation. I have started on an automotive conversion idea I had and have almost completed the redrive for it and should have the engine running it on a test stand by spring. This is a 4 cylinder inline liquid cooled turbo engine with dual spark plug head and fully redundant ECU's, injectors and sensors. Shooting for 250lbs with fluids ready to run and 150hp capability. I am putting it into a KR2S after all the kinks are worked out on the stand.
     
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  2. Nov 27, 2019 #2

    akwrencher

    akwrencher

    akwrencher

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    Nice. Pics if you have them, and what is the base engine? If you have the inclination, there are build logs on here as well. Welcome to the forum:)
     
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  3. Nov 27, 2019 #3

    ScaleBirdsScott

    ScaleBirdsScott

    ScaleBirdsScott

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    Look forward to seeing it.
     
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  4. Nov 27, 2019 #4

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    I will have to setup a hosting spot to share my pics in the next few days. The PSRU/redrive is gear drive and designed around 300hp at 2700 prop RPM with a 2000hr tbo and 99.9% bearing life expectancy. I may design a second one for this lower hp engine that would be lighter in the future. This first engine is a 1.4L and makes over 150hp stock and over 200hp reliably when tuned. I only want 140-150hp max takeoff and 100-120 cruise. This is an LE2 GM engine.
     
  5. Dec 3, 2019 #5

    Darius Plank

    Darius Plank

    Darius Plank

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    Do you hangar your KR at Tremont?
     
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  6. Dec 3, 2019 #6

    cheapracer

    cheapracer

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    Be watching this one...
     
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  7. Dec 3, 2019 #7

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    I am just building my KR but I'm actually south of St. Paris and very close to Tremont. I am taking my instruction at Grimes in Urbana though. Are you close?
     
  8. Dec 3, 2019 #8

    bmcj

    bmcj

    bmcj

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    Have you worked out the weight and balance for flight and also while setting on the gear? It seems like this will put more weight farther out on the nose. I know the KR already tends to be light on the tail and needs a weight in the back to hold the tail on the ground while the wings are off.
     
  9. Dec 3, 2019 #9

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    Bmcj, no I haven't but there are many great flying examples with the corvair engine that shares the 250lb installed weight so I do not foresee any major surprises in W and B.
     
  10. Dec 3, 2019 #10

    wsimpso1

    wsimpso1

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    Two gears or three? Do you have an estimate of your first couple of natural frequencies. Did you design in a COTS elastic element?

    Billski
     
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  11. Dec 4, 2019 #11

    Darius Plank

    Darius Plank

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    Grimes is home for me. Used to fly an ercoupe till the late 90's, Mel Parshal was my instructor. Want to fly again soon. Would be fun to meet.
     
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  12. Dec 4, 2019 #12

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    It's a strange design and contains 4 gears total but has a good reason to do so. I have a company in Cincinnati that will do the vibration analysis for me once complete. I have two different isolation coupling designs I'm wanting to try, well 3 but the third is more complex to machine and implement but would probably be the most effective.
     
  13. Dec 4, 2019 #13

    wsimpso1

    wsimpso1

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    I am the powertrain and isolation geek on HBA.com. I am always interested in seeing how the gear train and firing pulse isolation is done as well seeing how well it works. Maybe even visit to see your work?

    Billski
     
  14. Dec 5, 2019 #14

    proppastie

    proppastie

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    one might suggest testing this on a stable known airframe ......I do not believe it is very hard to get an "experimental product development" license say you wanted to do initial testing on an old C172...
     
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  15. Dec 7, 2019 #15

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    By the time my air frame is ready I plan to have enough hours on the engine/psru setup to be confident in its abilities. I
     
  16. Dec 7, 2019 #16

    wsimpso1

    wsimpso1

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    He did say he is putting it on a KR2S, an established and successful airframe.
     
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  17. Dec 7, 2019 #17

    Victor Bravo

    Victor Bravo

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    Chris welcome to this forum. It certainly sounds like you are approaching this with some amount of thought and reason, which is refreshing compared to other things that have been discussed here. I believe you have already made a positive impression on some of the higher quality people here, good on you.

    If you hve not already made this assumption, no matter how loud or pointy any of these discussions get, most everybody here means well and wants to see this type of project succeed. So if any of the discussions accidentally get sharp-edged in any way, consider us to be a prickly and acerbic family that genuinely cares, in our prickly and acerbic way :)

    Yes, the KR-2 is well known and has a decent record, but I must agree with 'pastie that another airframe might be better for the initial testing. My reasons for recommending this are:

    1) the engine will be at the heavy end of the weight range that a small airframe like a KR can handle. When you are flight testing an engine I believe it is more conservative to use an airframe where the engine will be on the lighter side, because you will have plenty of additional testing and data recording equipment over the "normal" weight of the engine, and it is always a lot easier to add a little weight to the engine mount than having to put weight in the tail. Weight in the tail of an airplane creates dynamic problems (inertia) that can ruin your day in some stalls, spins, or pitch maneuvers.

    2) If you are testing a new engine conversion, especially along with another complex and fiddly component (PSRU or gearbx), IMHO you absoutely must approach the testing with the assumption that you WILL be having numerous "teething problems", adjustments, and issues all the way up to complete in-flight engine stoppages. So I believe the primary factor in choosing the airframe is the low speed handling, power-off control harmony, and off-airport landing ability. I believe that any aircraft on the "fast, sleek, efficient" side of the spectrum is absolutely the wrong thing to use.

    3) the OP mentioned that he is or will be building a KR2S. I hope this does not mean that (regardless of 1000 hours of test stand time) his flight testing of the engine will be at the same time as flight testing of a newly built airframe? That would be very ill-advised.

    I strongly believe that the right airframe for this project would be something along the lines of a Super Cub. Factory or E-AB doesn't matter. This type and configuration of airframe can handle anywhere from 65 to 180HP, is demonstrated to have full control and predictable handling with power out and the propeller stopped, and can land damage-free in very short or obstacle-filled places.
     
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  18. Dec 7, 2019 #18

    Chris Matheny

    Chris Matheny

    Chris Matheny

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    With a lot better glide ratio (1:12 vs 1:9) Than a 172. with the flaps I'm implementing stall should be low also.
     
  19. Dec 8, 2019 at 2:15 PM #19

    Chris Matheny

    Chris Matheny

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    I do see your points and maybe after I showcase the engine here someone with an airframe the likes of which you describe will come fourth and want to try the firewall forward package. I am trying very hard to keep the weight down and reliability up. This should come in at or below the weight of a Corvair conversion if I do it right. I'm not opposed to fitting my plane with an O-200 for the first couple hundred hours until all bugs are worked out and I've gotten the power off characteristics of the plane into my comfort zone. I appreciate all the opinions and understand completely what you are trying to convey, just know it will definitely be done in the safest way possible as it moves forward. Thank you.
     
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  20. Dec 8, 2019 at 3:08 PM #20

    proppastie

    proppastie

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    one of the issues as regard flight testing is the large gyroscopic forces involved in turns, pull-ups...etc. not able to be tested on a stand.. see about insurance buy's for an airframe.
     

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