Downthrust ?

[dvint]

I built a vintage Ghostrider by David Boddington. This is a rudder&elevator
shoulder wing with 20% thick symmetrical airfoil with 38" span and 7' chord.
When I tried barrel rolls it lost a lot of altitude (not due to a power to wt.
ratio deficiency) . Later,i found out that I had put upthrust in the motor
mount instead of downthrust.Could the upthrust have caused part of the
problem?
Thanks

[Sparky Paul]

Well, yeah.
A thick wing will need something to balance the drag around the FRL.

[AndyOne]

dvint,

I agree with Paul, the drag of the thick wing combined with its position above the thrust line will require downthrust. I guess you were compensating for the incorrect thust angle by adding a lot of down trim although rolling with rudder elevator only will always cause quite a lot of barrelling and loss of height.

The 38" span version was the the mini version of the Ghost Rider, I had two of the larger 50" versions way back in the 70s. One thing to watch out for is that the fin/rudder was optimised for Galloping Ghost control (hence the name) which meant that it was a little small for ultimate stability if put into extreme manouvres using more modern proportional gear. I found that the Ghost Rider 50" would get into a flat spin and there wasn't enough control authority to get it out. I never did get round to curing the problem but I guess adding to the rudder area would help.

Andy.

[Sparky Paul]

"Galloping Ghost"... had a few of those. It's amazing it worked at all. Those "Mighty Midget" motors with the gum-band centering.. cute l'il things.
I don't recall any "interference" from all the wire scraping on wire, but maybe the old 27Hhz stuff wasn't sensitive enough. :)

[vintage1]

"Galloping Ghost"... had a few of those. It's amazing it worked at all. Those "Mighty Midget" motors with the gum-band centering.. cute l'il things.
I don't recall any "interference" from all the wire scraping on wire, but maybe the old 27Hhz stuff wasn't sensitive enough. :)

All that motor jumping around and you wouldn't see interference if you had it anyway.

Galloping host was controlled interference ....