Tailwheel a *****cat on grass but a wild animal on pavement

[azsportpilot]

I am a Sport Pilot CFI with over 500 hours of tail-wheel time in quite a few different models, but this one is really challenging

I have a new student with a really nice 1999 Kitfox 3 w/ 80hp 912

You could not ask for a more stable, gentle tailwheel plane when on the grass, but paved runways are a different story

The mains track straight and true but as soon as the tailwheel touches down it swerves radically from left to right, as it slows down it gets even worse

I have flown Kitfox’s before but I don’t remember any abnormal handling characteristics

When preflighting, the tailwheel assembly and associated cables & springs all appears normal

Any ideas?

(I previously mentioned this elsewhere in an unrelated post, but felt this question should be in the "General Discussion" area, if incorrect area moderator please move)

[Dave S]

John,

There has been lots of technical discussion about diagnosing tailwheel issues and setting up tailwheel assemblies on Kitfox aircraft on this list.

You might find a lot of good information archived if you would like to use the search function - start a search on "tailwheel" and I am sure you will see a bunch of information that might be of interest to you.

Sincerely,

[kmach]

What make and model of tailwheel ? What type of tailwheel spring ?

If the geometrics are not correct , than you can have allot of problems. The main issue is usually the tailwheel vertical axle angle, it should be very close to straight up and down .

[Av8r3400]

Suggestion 1: Check the orientation of the rudder to brake peddle position with your feet. You can adjust the brake masters and rudder cables to position everything better to you as an individual.

On my yellow plane with the "C" style brake peddles the more right rudder you apply the more the left brake extends into your feet. Couple this with a tailwheel that unlocks with a hair trigger and it can be a tricky little devil in inexperienced hands.

After I tweaked the brakes and rudder cables for my short legs, handling was much better.

Suggestion 2: IMO, the early planes (I - IV-1050) lack enough tail to be an effective wheel lander. The rudder runs out of authority much sooner than the elevator which means the yaw control is gone aerodynamically before the tail wheel would come down.

I have wheel landed my plane, but I see no reason to do it as a norm. I definitely do not in a cross wind. The 3-point lands slower and gets the wheel on the ground and the tail under control sooner. Again, IMO.

[azsportpilot]

I don't know, I'm guessing whatever came with the Mk 3 kit in 1999

it is solid non-inflatable

the student/owner just ordered an inflatable 6in Matco.... this one

http://www.matcomfg.com/TAILWHEEL6PN...v-3373-13.html

should be here soon, hopefully improving the situation

[kmach]

The Matco tailwheels have worked very nice for me.
I have had the WHLT-LD , now converted to the WHLT-8D . I rigged them according to the Matco instructions. They have a video on their website that was helpful. I hope it fixes the problem for you.

[azsportpilot]

the one the student/Owner ordered is the WHLT-6P

any opinions, did he get the right one?

[t j]

Another thing to check is main wheel alignment. Here's a how to thread.
http://www.teamkitfox.com/Forums/sho...ighlight=align

[azsportpilot]

thanks for the link TJ

i suspect there may be an alignment problem, it is so bad on the pavement that it's hard to believe it is just the tailwheel causing the problem

it really wants to dart off

[Peteohms]

I used to have the same problem on my Kitfox III. some of it was my big clodhoppers touching the brakes on landing. The rest was tailwheel. I have a new Matco 8" and apparently I don't hit the brake with my feet anymore. No problems anymore.