harphunt

Not sure where to post so I'm puttin' it here. If converting from tri-gear to a tail-dragger, does the rear wheel need to be steerable? If so, how do you recommend I do it as the rudder does not extend below the elevator. Thanks.

peace

alfredbmor

It does not need to. But you will need some more work, You will need a tail wheel bracket like this one (for a 40 size):

http://www3.towerhobbies.com/cgi-bin...?&I=LXD850&P=7

or one like this one:

http://www3.towerhobbies.com/cgi-bin...&I=LXFV47&P=ML

Then you will have to lock a wire to the rudder near the hinge line and make it work with the stuff that comes with those brackets.

A photograph of your project will be very helpful.

Also remember to move the main landing gear a little bit ahead (not too much), so you can make the tail stay down when your airplane is on the floor.

GaryHarris

http://search.rcuniverse.com/search....archwhere=both

RussianFlyer

When I converted my LT-40 to a taildragger, I basically mounted a dubro plastic bracket with its hole directly in-line with the rudder hinge line. then I drilled a hole vertically through the fuse all the way to the rudder. I believe I bent a new tail wheel wire out of some music wire and made it long enough to go through the fuse and up to the rudder. At the rudder end I simply made a 90 degree bend and used the rudder control horn backplate to retain it against the rudder. It sounds a bit complicated, but i think this is probably the easiest way to make a steerable tail wheel for the LT-40. So in summary, drill hole in fuse, bend your own tail gear wire, make it extend to the rudder control horn, sandwhich top of wire against rudder. All in all its a 15 minute affair

phatbob02

My Feedback: (126)

I built two LT's and used a servo.

harphunt

So, I gather I need to make the tailwheel steerable and not able to pivot freely. Phatbob, I assume you have that servo slaved to the rudder servo with a mix somehow. Thanks for the description Russianflyer. Perhaps I could pull-pull from the rudder servo. Thanks all.

peace

RussianFlyer

You could make the tail wheel pivot freely. It would probably not cause that many steering issues since the LT-40 has a fairly good sized rudder. If anything, try that first and if you like the way it behaves, don't make it any more complicated

shd3920

How do you have this set up to work with the rudder servo? I am interested in converting my kadet to taildragger.

phatbob02

My Feedback: (126)

I mix 2 channels in my DX7. I did the same in my Eindecker and I have the pilots head turn with rudder.

carrellh

The simplest way is to use a Y harness and plug the rudder and steering servos into it.

carrellh

We have a WM Super Stunts (looks sort of like a "Stick") with just a tail skid and it handles pretty well on the ground.

Rodney

If you are flying off a grass field, you can just put a skid on the tail, really no need for a wheel. That big rudder will let you taxi quite nicely with just the skid.

phatbob02

My Feedback: (126)

A Y harness doesn't work if the servo's are facing opposite directions, and a reversing harness doesn't work with digital servo's.
With mixing you get individual end point, and directional adjustments on each servo.

You could also use a pull-pull system on the tail wheel using just the rudder servo.

SeamusG

I did a thread on converting my LT-40 kit to include a bolt down wing and tail dragger.

www.rcuniverse.com/forum/m_9378908/tm.htm

harphunt

Wow! Lots of great ideas. Great thread SeamusG. I was watching "Piece of Cake" last night and thought I saw the Spit's tailwheel spin freely as it bumped the daisies. The Spitfire is a bit heavier than a Lt-40, though. If left free, I thought I might have problems on the ground with a crosswind. If a skid would work, why not a fixed wheel? Still mulling. Thanks.

peace

shd3920

Would that be a typical aileron y-harness or a reverser?

SeamusG

The all up weight of the LT40 is 7.5 lbs. The manual says 6+?!?!? 6 plus 1.5 lbs.

I used a small Hitec HS 81 servo mounted opposite the rudder servo and just below and behind - still totally within the "wing bay". Both the rudder and tail wheel use CF tubes with 2-56 threaded inserts with alum. collars to strengthen at the outer ends. I use a Spektrum DX7 and AR7000 Rx 'cause I have dual aileron servos (each on its own channel) and the tail wheel servo is on its own channel as well - that's 6 channels. Could'a used an AR6200.

Watch the weight on the tail 'cause it can get a bit out of hand. SIG uses very light balsa to help but depending on how "bullet proof" you make the TW the weight will follow. Just remember that 1/4 oz. at the tail will move the CG 1/8" whereas 1 oz. at the firewall will also move the CG the same 1/8". You add 2 oz at the tail you'll need to find 8 oz more at the firewall.

SeamusG

BTW I also converted my first plane, a Kadet Senior ARF, to a tail dragger. I used a pull-pull off of the rudder servo's horn - just made sure that the overall width at the servo horn was the same as the overall width at the tail wheel horn. I use some left over clear tubing to route the wire through the fuse. If interested I can post the pics for the ARF mod (about 30 in all).

Flew great until the SIG wing collapsed in flight. Em, nobody ever mentioned "throttle control" while I was "in training" [:@]

phatbob02

My Feedback: (126)

I did the same with my first Kadet back in the early 80's. One big loop under full power and I had just re-kitted the plane.

carrellh

If you do not have a radio that will do the mixing, you'll just have to hook some stuff up, see what happens, and adapt to it.
The first Y I would try is same as you'd use to hook two aileron servos to the same receiver channel.
phatbob02 pointed out that the steering servo might turn the wrong way so that could be an issue.
You can get a reversing Y as long as your servos are compatible with them.
Another possibility is mixing servo brands. Hitec and Futaba turn opposite directions so you could go that route.

shd3920

How can this be done on the rudder servo if that servo is already being used for the rudder control? Photos would be a great help. Thank you.

phatbob02

My Feedback: (126)

Check out this site for some Kadet mods.

http://www.his.com/~rb/rob/senior.htm

This is one of his pics.
You can see two cables that are used for the tail wheel on each side of the servo. One side of the servo arm also has the rudder control rod.

repirazz

http://www.pacaeromodel.com/Knockabout/Taildragger.pdf Heres another method of making a steerable tailwheel. not as cool as a pull-pull system but cheap, effective, & simple. (similar to russian flyers method) Works well on my LT-40.
-rep

SeamusG

repirazz - thanks for the thought but the link she no work ...

repirazz

Sorry bout that, try this one.
http://www.pacaeromodel.com/Knockabout/Taildragger.pdf