Don Fry Posted March 1, 2023 Share Posted March 1, 2023 Respect Simon. If only truly, utterly stubborn determination. See Ken Anderson’s identification photo. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 5, 2023 Author Share Posted March 5, 2023 Just a quick up date. I have now tested the P13A, not that you could really call them flights, four times so far without damage. Which shows there is now some degree of control. 😉 The latest modification is to move the battery forward about 10 mm to improve the pitch stability. The original CoG position was just a best guess. It doesn't look like there will be much calm weather for a bit but the moment I get what I would call a proper flight there will be a video. 4 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 27, 2023 Author Share Posted March 27, 2023 (edited) Calm and sunny today so I flew the Lippisch twice with the battery further forward and several clicks of up trim added to create a compensating reflex. No damage. Sorry no video. There is story attached to that as well. It still has difficult characteristics in that it appears to have zero longitudinal stability despite the best efforts of the gyro. It just about keeps level flight but if the nose rises at all it just continues to rise quite slowly until at about 45 degrees AOA when the drag exceeds the thrust so it stops flying and the nose drops. Recovery is very quick but it is hard not to over react and start the cycle again. It is possible the CofG needs to be a bit further forward but at some point it will simply run out of elevator authority. My guess is that its very thick blunt nosed delta wing section and the large area of the fuselage meas the CofP does not move rearward with an increased AoA so it has limited stability and it does not stall either. The CofG may have to be surprisingly well forward to ensure it is always ahead of the CofP. That is next step but I could be wrong. 😉 Edited March 27, 2023 by Simon Chaddock 6 Quote Link to comment Share on other sites More sharing options...
Chris Freeman 3 Posted March 28, 2023 Share Posted March 28, 2023 Well done Simon. Quote Link to comment Share on other sites More sharing options...
Graff Posted March 29, 2023 Share Posted March 29, 2023 Strange about the flying characteristics.... I used to fly a 1.2 m span Lippisch delta on the slopes. And it was extremely stable. It had the standard gentle oscillating in roll at high alpha. Are you sure about the wing design? The original has some built in washout. Quote Link to comment Share on other sites More sharing options...
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