Jamara Fournier electric sailplane

[simonbutler]

I have a Jamara Fournier electric sailplane running on a dd480 motor.Glide tests have been a success.When hand launching under power,the plane starts a gentle climb with no elevator control.After about 15 metres it rolls violently to the right.It does not appear to be losing air speed,but this does appear to be a tip stall.
Can anyone offer any help to overcome this problem.


Simon Butler

[Ollie]

If I remember correctly, the Fournier has a highly tapered wing planform. Wings with such planforms are very prone to tip stall.

You can trim the model to fly faster with a couple of clicks of down trim to give you more stall margin. You can add some down thrust to reduce the nose up tendency under power. You can check the wing for washout. Perhaps the right wing has a little less washout than the left wing. If the washout is not the same between the left and right wing make them even but don't reduce the washout in either wing. If the tip stall persists after adding a little down trim and down thrust, consider increasing the washout in both wings.

[simonbutler]

Thanks for the suggestions.I'll give them a go.
Many Thanks

Simon Butler