Hempel KA-6 trim issue?

[LRFitch]

I have a slightly used Hempel KA-6 that I bought from Bill (his own personnel glider) fully equipped with all needed flight control equipment. I've flown the model several times over the past two seasons, and find the same trim issue every flight. The model porpoises up and down when in straight and level flight. Others that have flown the big bird say this is normal, and I need to just "stay ahead of the oscillations". I've never flown a glider this big, but have flown several 4-6 meter gliders, and not had this issue. The balance point (as long as I've had the model) is just at the front edge of the large wing tube. Have others with the KA-6 had similar issues? HELP!!

[gunny11]

Send a pm to Erichs he has one. http://forum.scalesoaring.com/member/59-erichs

[lenb]

Defiantly talk to Erich, but sounds like a little nose heavy.

Just for fun. next time you fly the plane, strap about two ounces on the elevator and go fly it again.

If its nose heavy, as the plane flys along and starts to pick up a little speed, the nose will rise, as it slows, the nose will fall...... Rise and repeat.

Worth a try,.

[Tom]

Mine doesn’t do that at all.........and thanks for forgetting that I have one also guys! 🤪
And yes it is nose heavy.....balance point is smack dab in the middle of the front joiner.......not at the front edge. With the CG in the middle of the joiner you will be needing some down trim in the elevators.........basically the bottom of the stab/elevator will be flat........at this CG it is a pussycat.....fly’s like a old school trainer.....3 speeds....slow....slower......and backwards!

[LRFitch]

Tom, Len, Thanks for the info. Len, you described my problem perfectly. Tom, I will get it to balance farther aft. I take it you balance yours fully assembled (wings on)? I have not gotten to "backwards" yet, but it is slow. However, on landing, it just keeps going down the runway--lots of momentum.

Thanks Again,
Larry

[Tom]

Tom, Len, Thanks for the info. Len, you described my problem perfectly. Tom, I will get it to balance farther aft. I take it you balance yours fully assembled (wings on)? I have not gotten to "backwards" yet, but it is slow. However, on landing, it just keeps going down the runway--lots of momentum.

Thanks Again,
Larry

Yes balance fully assembled........and yes it wants to roll for quite a bit.......Erich was thinking of installing a brake on his.

[LRFitch]

Tom, Thanks for the follow-up and additional info.

Larry

[lenb]

Oh, one more thing, Tom Pack has one too and he can be a wealth of knowledge. Im sure he will have some helpful suggestions.

[horsefeetky]

question for you guys that own these.. i have bought one in the white color new in the box to finish out and fly.. but it also comes with 2 extra sets of wings un covered.. any suggestions for a build using the wings with a scratched out or kit cutters version fuse build..

thinking the wings would go well on an old school type with parasol wing attached to a gondola fuse with struts..........?????