Citabria Ailerons Extremely Stiff over 90 MPH?

[Cowboys Air Ranch 84ME]

I have a 72 Citabria w/ O-235 and wood spars. When I get up to cruise, over 90 MPH or higher, Ailerons get Extremely Stiff. They go from about 5 lbs of pressure to move the stick right or left at below 90 mph, to about 20 lbs of force at higher speeds. Really a drastic change. I know it should get harder the faster you go, but this is not right!!! Any ideas? Rigging? Drag/Anti Drag Wires letting wing move in higher speed flight? Max speed in level flight is 110 mph @ wide open (2600 RPM) and only when I lean it aggressively.

 

[Ron86654]

Do you have Spades installed?

 

[Cowboys Air Ranch 84ME]

Howdy, I do NOT have spades. This seems to be extremely stiff on the Ailerons when you get up to any reasonable speed. Not like other 7ECA's that I have flown. Ideas?

 

[Hiperbiper]

Check the ailerons when centered. They should have a slight droop when static. I've seen people reflex the ailerons both "up" to supposedly get a higher top speed...it doesn't really work but it will cause the ailerons feel funny.
Also, check the tension on the aileron cables, pulleys and look for rubbing against ribs or compression tubes.
Just some cursory things to look for...

Chris

 

[Cowboys Air Ranch 84ME]

Howdy,

My mechanic and I opened up the wings, checked cable tension, binding, rigging and such. Found nothing out of the ordinary. Talked to a fella who once owned same model and vintage of plane, and stated that it is the nature of the beast.

He said he put some Aileron Spades on the plane and worked wonders, even with wood spars.

Anyone know where to get a set of spades and a STC for installation?????

Going to try a fish scale on the stick at various speeds to doccument findings and compare to other aircraft. But really leaning on trying a set of spades.

Cowboy in Maine

 

[Hiperbiper]

What cable tension did you get?

 

[aftCG]

You can find spades on eBay right next to the unicorn saddles. Paperwork is the road block since you can't transfer the STC. That said, they are fantastic.

Control feel is out of whack on this airplane with stick forces in roll being the one that gets your attention. The first time I flew my Citabria was the first time I flew one without spades and as I accelerated out of the pattern I had that WTF moment where I thought something was wrong.

For peace of mind I would triple check the cable runs and pulleys. See if you can get a couple of helpers to reflex those ailerons slightly upward (as if they're getting a flight load) and try the feel then. It might highlight a tight pulley or something.

 

[Bartman]

Howdy,

My mechanic and I opened up the wings, checked cable tension, binding, rigging and such. Found nothing out of the ordinary. Talked to a fella who once owned same model and vintage of plane, and stated that it is the nature of the beast.

He said he put some Aileron Spades on the plane and worked wonders, even with wood spars.

Anyone know where to get a set of spades and a STC for installation?????

Going to try a fish scale on the stick at various speeds to doccument findings and compare to other aircraft. But really leaning on trying a set of spades.

Cowboy in Maine

when we were attaching my wings i mistakenly put one aileron cable over the top tubes above the headliner and one below. I would imagine that this would bind up the cables as airspeed goes up if it were left that way. the ailerons and wing are almost exactly the same as the Champ so they're a holdover from a slower time. having said that, yours still sound too heavy so continuing to look is probably a good use of your time. even at cruising speeds around 100 mph roll is out of balance with pitch but it shouldn't be that bad. around 110 to 140 the roll forces go way up.

Thanks for your post and welcome to the site!
Bart

 

[Big Ed]

One of the original motivations for the Decathlon design was to improve Citabria stick forces, which were known to be excessive in roll.

 

[BB57]

Check for excessive cable tension. That will increase aileron forces, over and above the already heavy forces in a non spade equipped Citabria.

 

[Bartman]

do these help at all? from a Citabria service manual

 

[Hiperbiper]

Actually, anything above 15# on the aileron cables is overkill as long as the pulleys in the system are free to rotate.

Chris

 

[BB57]

Actually, anything above 15# on the aileron cables is overkill as long as the pulleys in the system are free to rotate.

Chris

Agreed. If you need to keep it in the specified range you want it at 20 lbs. More will equal heavier aileron feel.

 

[Cowboys Air Ranch 84ME]

What cable tension did you get?

Howdy, We got about #23 cable tension in the wing measured thru an inspection hole. Can not find anything wrong?

 

[Cowboys Air Ranch 84ME]

when we were attaching my wings i mistakenly put one aileron cable over the top tubes above the headliner and one below. I would imagine that this would bind up the cables as airspeed goes up if it were left that way. the ailerons and wing are almost exactly the same as the Champ so they're a holdover from a slower time. having said that, yours still sound too heavy so continuing to look is probably a good use of your time. even at cruising speeds around 100 mph roll is out of balance with pitch but it shouldn't be that bad. around 110 to 140 the roll forces go way up.

Thanks for your post and welcome to the site!
Bart

Howdy, I opened up the inspection panels in the wings, abd checked everything out. Used a mirror to see where or if anything was rubbing. Even checked accessable pulleys for binding under load. Nothing out of the normal was found.

 

[Bartman]

Do you know anyone with a similar plane that you can fly? Or you can let them fly your plane for comparison? It's probably good that you didn't find anything wrong. Maybe your airspeed indicator is off? What airspeed does it show at about 2500 rpm?

 

[Cowboys Air Ranch 84ME]

Do you know anyone with a similar plane that you can fly? Or you can let them fly your plane for comparison? It's probably good that you didn't find anything wrong. Maybe your airspeed indicator is off? What airspeed does it show at about 2500 rpm?

Howdy, I had planned on flying a newer Aurora but the weather is not very nice. I hope I do not miss this window. Besides, I am told that the newer models fly differently than the older stuff of same model. I will find out.

Cowboy

 

[BB57]

Howdy, I had planned on flying a newer Aurora but the weather is not very nice. I hope I do not miss this window. Besides, I am told that the newer models fly differently than the older stuff of same model. I will find out.

Cowboy

The metal spar wings are a little stiffer and all other things being equal roll rate is marginally better.

 

[Cowboys Air Ranch 84ME]

The metal spar wings are a little stiffer and all other things being equal roll rate is marginally better.

Howdy BB57,

I do know that the metal spars are stiffer. When I shake my wings up and down (Wood Spars) they flex slightly. I was worried, but my mechanic said that is normal for that aircraft.

We then looked at a Metal Spar GCBC which just happened to be in for annual, and the flex from rocking the wings up and down was almost not noticeable.

I am told that wood wings are more forgiving to a point, but can break faster with ground contact? Not sure about that?

Ken Winiarski
84ME Cowboys Air Ranch

 

[Bartman]

fyi

Wood wing aileron spades

currently sold spades Also have overhauled 150 HP propeller with spacer for sale $2500 plus ride

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