Tail Heavy Champ

Bob Eilers · Post by **Bob Eilers** » Wed Apr 06, 2005 11:50

My 46 7BCM seems to be growing tail heavy. When I set the trim at cruise it will creep aft causing the nose to raise. I have tried tightning up the trim friction wheel, but trim still creeps aft. Any speed above normal cruise requires quite a bit of forward pressure on the stick. The situation seems to be worsening and becomes extraordinary with anyone in the back seat. Anyone experience anything similar?

mike newall · Post by **mike newall** » Wed Apr 06, 2005 12:23

Sounds like wear in the trim system.

Check the pulleys throughout, they are prone to seizing, spend some time on the trim friction, it may require more than just tightening.

guest · Post by **guest** » Wed Apr 06, 2005 21:52

Bob, check the trim tab hinge, I had a problem with it on one of my Champs. It happened slowly so it was hard to detect. Paul Agaliotis

MikeB · Post by **MikeB** » Thu Apr 07, 2005 09:02

Bob,
The way you described it, it does sound like the friction lock is not holding the trim cable adjustment tight enough. When I put a heavier person in my Champ in the back seat, I have to adjust the friction lock tighter. The former posters gave you a couple of good ideas, too. It seems like the trim pulleys never get lubed at an "annual", especially the one set about halfway back in the fuselage that is almost impossible to get to unless you're a midget. One other thought: when you burn the nose tank fuel off, it alway requres more trim adjustment (nose comes up). If everything else checks out, I think I'd look at the trim friction lock further.

Tim Juhl · Post by **Tim Juhl** » Thu Apr 07, 2005 15:03

All the previous posts have made good comments. What I'm curious about is your statement about having to hold forward pressure. Is the the trim lever full forward at this point and you still have to hold pressure or has the lever moved aft on it's own accord? If you have a tail heavy condition with the trim lever full forward then you really need to find out what is going on.

If your lever is creeping then you may need to check the friction setup. For what it is worth, if somebody greased your friction lock it might not hold like it's supposed to.

Tim

Bob Eilers · Post by **Bob Eilers** » Sat Apr 09, 2005 12:02

Tim,

When I am alone in the Champ trim seems to function well at 2250/2300 RPM. If I set the power any higher the trim will creep aft. I don't have the trim tightened down tight and am experimenting with how tight to make it. When I descend and keep the power setting at cruise, I must hold the stick forward and trim won't stay where put - creeps aft. Basically, airspeeds above 80 indicated require forward pressure on the stick and trim won't stay put. Anytime I put another adult in the back seat, even with minimal fuel in the nose tank, I must hold forward pressure on the stick. The empty weight of this particular Champ is 840 so I have very little useful load. I will try cranking down the friction of the trim lever.

MikeB · Post by **MikeB** » Sat Apr 09, 2005 14:02

Bob, The way you're describing it, almost has to be the friction lock. It takes quite a bit on mine with a heavier back seat passenger.

Bob Eilers · Post by **Bob Eilers** » Sun Apr 17, 2005 11:40

Thanks for all the suggestions. Just tightening the friction on the trim control did the trick. However, I discovered if I tighten the friction to tight I can't trim up elevator sufficiently for landing - wind up fighting trim. After some experimenting I've got it figured out.

aeroncafan · Post by **aeroncafan** » Sun Jul 27, 2008 22:05

Any idea where to get one of the friction knobs used to tighten the friction on the trim tab admustment arm? Interestingly, I've seen one (won't say who's) with just a bolt throught it???

This particular Champ has started having similar behavior described in this thread.

Post by **joea** » Sun Jul 27, 2008 23:02

Is it the same as the one used on the Chief? I have seen Don Jones on Ebay selling those from time to time.

aeroncafan · Post by **aeroncafan** » Tue Nov 04, 2008 21:57

Not sure. It's listed as part number 1-2390 in the 7AC Service Manual. Sure would be nice to have one. Too bad my dad's retired (tool & die maker/machinist) and doesn't have access to a shop anymore

. He could make anything (according to original drawings and specs, of course). Sure wished he kept granddad's shop so we could have another parts supplier!

Jody Wittmeyer · Post by **Jody Wittmeyer** » Wed Nov 05, 2008 17:39

All the trim components are the same one the champ and chief. You can even use the champ cables and visa-versa.

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