Graupner Fox turbine project

[Dwazzer]

Hi chaps,

Well, I put up a ‘wanted’ ad on here a little while ago, and it was answered by Terry White! (Cheers mate!)
I bought a Graupner Fox glider off Terry (3.6m) that needed a little work to get flight ready, but was a really nice model!
I took some time sorting the rudder arrangement and the elevator setup so that it worked as it should and decided to fly it off the slope to see how it was...
To be TOTALLY honest, it was ok, but I didn’t really enjoy flying it that much...it required a lot of effort to find lift and then didn’t really reward once you found it I think I prefer to slope the more traditional type of gliders...Which made me decide to convert the Fox to a turbine glider!

I took some advice and changed direction relating to the turbine mount, making it a much more simple design.

I had a bit of a push and got it ready to maiden this weekend....and it was AWESOME!

I had to change the thrust angle to get it to fly right, but it was GREAT! Worth all the effort and expense in the end!

Here is a video of the Fox flying at Elvington, enjoy

[terry white]

Hi Dave,
Im so pleased you are making good use of the fox,It really does look awesome as you say.
I remember you telling me that you wanted to play with fitting a turbine to it as you had seen the Paritech boys performing with their fox at a show near you. You then dreamed to have a machine that would give you that same buzz.
Well you certainly have achieved that.
The vid quality was also extremely good .We are able to follow the model from launch to landing every step of the way. Very well done that man on the camera.
Your maiden landing was also super, better then mine after 100dreds of years of practice!

On a practical note though, she was really motoring at times and you were executing some fine high 'G' aerobatics as well. She was of coarse designed as a slower flying glider with much less 'G' force expected to be placed on its flying surfaces. So I take it that you have redesigned these areas now to cope with the greater stress. Can you share with us your alterations as I have another college who is contemplating doing the same thing to his fox.

How about you and your fellow flyers bringing it to some of the aerotow meetings around the country (After clearing it with the organizers first of coarse)

As for me I have two 1/4 scale foxes both with powerful Hacker geared motors up front that give me a great deal of satisfaction when flying them under power ( ) however they are not in the same league as your turbine fox.
finally there is now a full size turbo fox flying in Switzerland (can be seen on YouTube) and Guy Westgate tells that he is to fit a motor sustainer to his fox.

So we are still in keeping with the scale scene. (sorry scale police not this time)

Thanks again for sharing a great video and hope you continue to have lots more fox fun. Regards Ter.

[Dwazzer]

Thanks for the comments Terry,

The alterations made to the glider were minimal to be honest! The main area of strengthening was on the top where the turbine is mounted. I added carbon fibre cloth and a carbon fibre 'Tongue' Hysol'd into place for the turbine mount.

My style of flying isn't so aggressive as to need extra strengthening to the wings or surfaces and the all glass construction is pretty strong anyway

The only area I am considering some work on is the vertical stab and Rudder, but I'm pretty happy with her as she is

Cheers, Dave.

[terry white]

Brill Dave ,thank you (Wished my workshop looked like yours in pic No2)

[Euan Galloway]

As most will know I have been using turbines on my gliders for a few yrs and for me it’s a cheap way to get a self launch scale aerobatic Glider without carrying it up the slope or waiting for s tug pilot ! I tried a high power EDF but was put off by the costs of lipos.
Several full size now use turbines do we can argue it’s scale ?
Dave flew his Fox very well and made it easy for me to film !!

[Euan Galloway]