Here we go again. Test flight 3 for my Lidl Fusi Hawk Wing Vampire. Didn't fly into a tree this time and almost had it, but have recaculated CG and I think it was way to nose heavy which might account for the stall when I landed to trim it. If you make it to the end of the video you'll see that that's fixed now as well. You'll have to wait for flight 4 to see if it really is sorted! He who perseveres wins!
Lidl Hawk Vampire Flight Test 3 - was it as bad as the maiden and re-maiden?
- Thread starter Bonzodog
- Start date
quorneng
Master member
I do wonder if some of your sensitivity is from the vertical flexibility of those thin tail booms.
Any elevator input will alter the force generated on the tail plane which if you think about it will cause a change in tail incidence that will tend to counter the elevator effect. Only when you apply a significant elevator input will boom stiffness come into play so giving a rather "delayed" elevator feel.
I note that on the full size Vampire the booms are not circular but oval, and even more so on the bigger heavier Sea Vixen, so are stiffer vertically than horizontally.
My Depron Venom with scale section tail booms built up in Depron are flexible enough to give this effect. particularly if flying fast when you expect the elevator to be more rather than less effective!
I know that "nearly lost it" sensation quite well.
Any elevator input will alter the force generated on the tail plane which if you think about it will cause a change in tail incidence that will tend to counter the elevator effect. Only when you apply a significant elevator input will boom stiffness come into play so giving a rather "delayed" elevator feel.
I note that on the full size Vampire the booms are not circular but oval, and even more so on the bigger heavier Sea Vixen, so are stiffer vertically than horizontally.
My Depron Venom with scale section tail booms built up in Depron are flexible enough to give this effect. particularly if flying fast when you expect the elevator to be more rather than less effective!
I know that "nearly lost it" sensation quite well.
Hi and thanks for the input. I hadn't considered that but I just picked it up and tested to see how much flex there was in the tail booms and they're surprising rigid. Very little movement up and down or twisting. I recalculated CG and it was very nose heavy (if my new calcs were correct!) Which didn't help with my hand launching. And initial problems I had with this were throws too big and an unreliable, flakey elevator servo. Also discovered that the elevator was quite stiff the way I'd hinged it, so new servo and freed it up. I'm reasonably confident that flight test 4 will go well!
. But it's a fun experimental build and you do learn a lot on the way!