Rudder trim tab

[C5Engineer 1170]

Well after one very long X-country and another one in the planning stages I'm adding a trim tab to my Rudder before I go. I made one up and used 3/4" wide 3M double sided tape. I went to test flight and it was really gusty out up to 21kts. I lifted off almost instantly and something did not feel right at all. The Rudder felt stiff. I pulled the power and floated down the runway with the biggest handful of airplane I've had in a while. I did not stop chirping my tires till I was at slow walk of a speed. The damn thing would just not stop flying. Anyways note to self don't test fly with 12kt gusts up to 21. I quadruple checked that I was not getting any interference with the tab location. I talked to a guy on the field that is fairly knowledgeable and he said it was way too big so I cut it almost in half. The wind kept howling so I never did get to test fly it again.

Does anybody have any input on this... does where it's located vertically make any difference? Cessnas put them on the very bottom. I wanted it under the elevator simply for visual reasons. What do you think of the size? Never measured it after I hacked on it. Once I get it dialed in gonna just rattle can it white.

The initial tab I started with

After hacking it down some

I also upgraded my 2" snap vents to 3 1/4 ones that can be rotated to be completely closed.

Tip: A travel coffee mug is exactly 3 1/4 OD on the top. I traced it onto cardboard, made a template, centered it over the existing hole and transcribed a line. I then just used a sanding wheel on my dremel and went after it. The instructions have you use a hole saw which is a pain and you will end up with a hole that is too big and your vents will rattle.

[dholly 718]

My rudder tab is smaller, higher and bent to the right. Don't really have any good pics, but you can kinda see with these.

[C5Engineer 1170]

Thanks Doug! I ended up cutting mine down twice. The first time it was WAY too big and made my airplane super squirrelly on the runway. The second time was still way too much so I cut it down again and now it works great.

[dholly 718]

I find it odd that we both have counter-clockwise turning 582's, but opposite side tabs.

[Av8r3400 1179]

Maybe there is too much built in offset to your vertical fins? Didn't the Avids and 1-3 Kitfoxes have offset built into them??

(Edit: Doug- your tab is bent opposite mine - for left rudder input. So it would be correct to your engine rotation with a zero offset tail. But Joey's is the same as mine - right rudder input. His may be to counter an excessive tail offset. )

Edited 31 Aug 2010 by Av8r3400

[dholly 718]

Yes, that was what I was thinking. I know the early Avids had an offset but I don't believe I've seen same mentioned for the KF-III.

[akflyer 1427]

My rudder tab is smaller, higher and bent to the right. Don't really have any good pics, but you can kinda see with these.

I see something really disturbing here... the ole fat bastard looks like it has become a shelf for damn kitfox turtle deck... It is a sad sad day in fat bastard slackers history....

I know that some people took the left offset out on the rudder when they built them and shimmed the thrust into the engine depending on which engine they used.

[dholly 718]

I see something really disturbing here... the ole fat bastard looks like it has become a shelf for damn kitfox turtle deck... It is a sad sad day in fat bastard slackers history....

I know that some people took the left offset out on the rudder when they built them and shimmed the thrust into the engine depending on which engine they used.

Leni, you'll be happy to know that the scruffy old KF upstart is off site and the Fat Bastard has resumed it's rightly place center shop.

[akflyer 1427]

Leni, you'll be happy to know that the scruffy old KF upstart is off site and the Fat Bastard has resumed it's rightly place center shop.

SWEET, have you been putting some hours on the KF? This summer has been so crappy that I am lucky if I have 50 hrs in mine.. Normally I would be getting in 250-300 hrs just on floats in the summer.

[dholly 718]

Frustratingly slow waiting for the weather and instructor.... only ~10hrs of solo fast taxis and crosswind crow hops, trying to feel out the TW thing. It's different yeah, but nothing bent yet. 2hr today in 8G10 straight across the runway which was interesting. Started ok but things got sloppy so I shut down and told the instructor if I bounced it more than a few feet I was going to firewall it and go around. He promptly ran off with my plane to do a stall series and get himself more familiar with the plane. He knows I'm anxious to get on with the 10hrs dual and I'm guessing the real schooling starts soon...

P.S. - sorry for the thread jack Joey

Edited 2 Sep 2010 by dholly

[C5Engineer 1170]

Frustratingly slow waiting for the weather and instructor.... only ~10hrs of solo fast taxis and crosswind crow hops, trying to feel out the TW thing. It's different yeah, but nothing bent yet. 2hr today in 8G10 straight across the runway which was interesting. Started ok but things got sloppy so I shut down and told the instructor if I bounced it more than a few feet I was going to firewall it and go around. He promptly ran off with my plane to do a stall series and get himself more familiar with the plane. He knows I'm anxious to get on with the 10hrs dual and I'm guessing the real schooling starts soon...

P.S. - sorry for the thread jack Joey

No worries Doug this is way more exciting than a trim tab