Hey everyone,
I recently purchased a PT-40 off tower, and have steadily been working on it. Well, I finally got to the nose gear installation, and I realized that when I installed the pushrod through the guide and connected it to the steering arm, the rod binded inside the guide. I was hoping some of you had some advise on how to fix this problem.

Thanks,
kinney

Yup ... been there, done that.

Here's my solution ... before and after.

The binding as not as much of a problem as the control-arm on the nose-gear bending and flexing so much. Also, taildraggers are actually just easier (off grass).

gus

Make sure that there are no kinks or bends in the wire rod. Make sure that you don't have the guide tube crimped or kinked & that any bends are gentle. Lightly grease the wire rod with vaseline.

Better yet -- convert to a tail dragger.

Just got to that part of the construction myself. So far, everything about this build has been solid. But the landing gear... its a shame such a stout plane is supported by such flimsy gear.

Gus, can you elaborate a bit on your conversion? Did you somehow bolt the tail wheel to the rudder? What brand landing gear is that in front? Anything else I need to know before attempting?

Thanks!

Be sure that the arm is close to the firewall with the nose wheel straight ahead. There really does not have to be a ton of travel in a nose wheel. A little goes a long way. Most binding occurs if you have the arm too far out. The pushrod leaves the outer casing and has to turn toi get to the arm. Straight on is the best way to describe how you have to hook one up.

Mark Shuman

No problem.

The main gear is (I believe) DuBro "Dural" .40 size gear. it was $14 canadian at the LHS. I got great planes axles, and 1/4-20 nylon bolts to mount the gear to the fuse.

I guessed that the gear should get mounted with the back-end of the gear in line with the former at the front of the wing. So, I pulled out the tank and used 6 pieces of 1/4" square bass-wood and jammed them up (with epoxy) against each other, and against the former. Thus, the fuse was re-inforced to take the gear. It was really fiddly to get the bass-wood in so that it fit snugly from the left-side "fuse doubler" to the right side "fuse doubler", hving to fit it all under the "tank floor". I imagine you can picture in your mind what I did.

Once the fuse was re-inforced I pushed a T-pin into the fuse so that it came up into the F2 Former (i.e. I found the back-end of the main gear). I lined up the gear using the T-pin as a back-stop, and marked where the gear mounting bolts would go. I drilled the holes and tapped them to 1/4-20. To make sure the gear doesn;t moove around too much I also added some lite-ply "gear guides". See the pics.

The tail-wheel was easy. See the pic. I used a sullivan .40 size tail wheel (first I cut the monocote, and re-inforced the bottom of the fuse with lite-ply).

gus

Nice looking job, but it was a lot of work. I have found that mounting the main gear bolt-down block on the floor of the fuse, tight against the back side of the former, works very well & you can easily get at that location from the open battery/servo bay. This puts the wheels just under the leading edge, which is a good location. If you get the wheels too far forward, the take-offs can get squirrely.

Gus
Nice conversion, now I have something to do this winter. What is the dimension of the gear width, as I will probably make a set at my shop out of T6.
Thanks
-Tom

I believe It was Great-Planes gear I used, not the Du-Bro.... not sure anymore.

I believe it was http://www2.towerhobbies.com/cgi-bin...?&I=LXJ922&P=0 They list the width as 10 3/4" I'll confirm later.

The ground handling is more than fine. Been up for at least 15 flights since conversion, and not one ground-loop or nose-over (flying off grass). I am very happy with handling. I think putting gear behind former would be too far back, even if it was easier to install.

The spring on the sullivan tail-wheel is just pushed up into the ridder with an appropriate bend to get around the curve of the rudder. Turning on the ground is just fine.

Thanks for the compliments and all. I did not try too hard to keep the aesthetics up, but the messy parts are pretty well hidden. I really did the conversion for five reasons...
first, the control arm on the nose-wheel broke and the loc-tite on the set screw was so strong I stripped the set-screw removing it.... i.e. I broke my nose-gear.
second, the nose-wheel just has too short a moment on the plane (i.e. a tuft of grass can "bump" the plane off course on the ground... basically too squirrely)
third, the nose wheel was too flexible at times (bending sideways when trying to turn, etc. I once hit a particularly strong tuft of grass on take-off, and the nose-wheel "rebounded" into the prop. Shaved a 1/4" flatspot in to the tire... and broke the prop).
fourth, my trainer is being used by other people now (I am instructing friends/family), and they need to get tail-dragger experience before they move on.
five, I could.

gus

If you are flying off grass, you do not need the tail wheel, a skid works just as well. Be careful where you mount the main gear when you convert to the tail dragger version. Have the axle about one inch ahead of the CG when the plane is held level (tail up in flying attitude). If you get the gear to far forward, landing will tend to bounce badly unless you make a perfect landing and will be difficult to keep on a straight tack on takeoff; to far back and the plane will tend to nose over during taxi.

Which hole are you using on the linkage that is attached to the top of the nose gear? I had to use one furthest out to make it work properly. This also lined the pushrod up better with the tube exiting the firewall.