Building Tips and technical articles. > Building techniques
Endgame IV Build
Ken Culbertson:
I built Endgame as my last PA ship that I would fly till one of us died. Well, it got murdered in a house fire, so I built Endgame II to take its place. It flew OK but I have always wanted to try a canard, so I added one and II became Endgame III. III is an unqualified success but I am still above ground and I have always wanted a twin PA. I had one of those, I think it was Sterling, P-38's with two Fox 15's. Ever try and get two Fox 15's to start at the same time? It was a poor performer but the sound, ah the sound. Well, after seeing Frank McMillen's twin which I commented on in the Endgame III thread it is official. What appears to be the first twin canard is on the worktable. There will be enough changes to give it a new name but it still has the same roots so it will be IV. Aside from the twin setup it will have a 1" longer nose to give the canard more leverage and get it away from the props. It will be totally in clean air so it should be even more effective. One thing I noticed on III was that the large elevator/stab was too far back with the addition of the canard. The elevator became way too sensitive along with the logarithmic. Great for corners but you have to fly it in-between them too! So, I am moving it from 19 1/2 to 18 1/4. I am switching airfoils from the Geo-Bolt to Geo-XL. I used it on my Trifecta and the thinner wing seem to penetrate better and still have gobs of lift. The last change I am making is going to inline. I have no experience with this one so I am relying on those who have gone before to be right when they say that a twin electric should be inline. I will post drawings/plans when they are finished for any and all to laugh at. All suggestions will be appreciated.
Things that I have to decide on include the logarithmic. III has a tendency to "snap" in a turn. What I mean is that if I need to increase my turn rate in a round just a little it seems to overreact and "snap" making me miss the bottom. I attribute this to having the logarithmic set to transition too soon probably from adding the canard. I can't change the logarithmic to fix it on III without replacing it, which I may do, but I can correct in on IV. The question becomes, do I need a logarithmic at all with a canard? III will turn as tight a corner as I want to fly and keep the wing in one piece. I have yet to stall it in a turn or attempt a "bang" corner. I have done maneuvers with corners so tight as to be annoying to those watching - without any stall. Never thought that was possible.
I have another question but I will make it in a separate post, so my ramblings don't clog up Sparky's drive.
Ken
Ken Culbertson:
This is the question. Do all of the horn, pushrod configurations have the same effect. Ignore the logarithmic, it is only there because it reverses the direction of the elevator pushrod. I really need to use #2. All angles are 90 degrees to the pushrod.
Ken
john e. holliday:
To me I built the Sarpolis canard to prove to prove to myself and others that they will fly and do a pattern. I have witnesses to that when the LA 40 is set right. So I constructed my version of a Ringmaster canard without the rear moving surface The canard has no control of the plane until it gets moving through the air. I had an LA 25 for power. Had to extend the gear as far forward as I could get it so the plane would not nose over. Once it got moving and control of the canard started it flew better than I fly. I learned that is why the Sarpolis canard had the rear moving surface. It was to keep the nose up until some speed was obtained. Yes it was strange to look at while flying. When I get to rebuilding the Ringmaster canard it will get a moving tail surface. Works like an elevator.
By the way searched for canards on the internet. A lot of good reading and why people who have built the Bert Rutan canards had to learn a few things. They don't handle like a Cessna or Piper Cub. D>K
Lauri Malila:
--- Quote from: Ken Culbertson on December 26, 2023, 02:34:02 PM ---This is the question. Do all of the horn, pushrod configurations have the same effect. I really need to use #2. All angles are 90 degrees.
Ken
--- End quote ---
Number 1 would be interesting to watch as flaps turn to wrong direction compared to elevator. L
Ken Culbertson:
That was what sketching things in a hurry will do. I was trying to illustrate the direction with a logarithmic and left that tiny bit of information out. I will revise the illustration! Thanks for pointing that out. What about the other two?
Ken
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