dash008

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Hello,

I've been reading a lot but haven't posted much. I thought somebody might be interested in some modifications I'm making to my Tower Trainer.

I bought this plane back in the spring and flew it all summer. It's a great little plane, flies really good. It's only problem is the landing gear... Too weak. You can't help but bounce three or four times no matter how good your landings are. I had read about the weak landing gear so was anticipating this before my first flight. After the first flight, put some PT-40 landing gear I had on it and had no problems with bounce landings after that.

Anyway I fly off some pretty rough grass and got tired of having to straighten the nose gear all the time so this winter I am converting it to a taildragger. I also cut off the cheek cowls. I don't see what purpose they serve other than adding weight and also I recently bought a stik and like how easy the engine is to work on with that airplane. Plus I was able to use a piece of the cheek cowl as a reinforcement for the new landing gear (see picture).

I'm trying to figure out how to do the tailwheel now... I bought a dubro tailwheel bracket and was going to put that on there, but it doesn't look really beefy enough... I guess I should have ordered the 60 size. Today I purchased a Sullivan tailwheel system from a LHS. It looks much better so I think I will put that on. Making it steerable is going to be kind of a pain. Would it work ok if I just left it free castering? Or should I lock it straight?

Anyone have any experience with tailwheel conversions?

I was planning on doing a bolt on wing as well, but after my experience with the stik I changed my mind. [&o] That's a subject for another post...

w8ye

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Good job you are on your way

w8ye

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On the tail wheel - I've done a few and I've seen all kinds of approaches to the steering problem

On mine in the picture I made a longer wire to go up and bend 90 degrees and epoxied into the rudder.
You have to have a bearing support up through the fuselage that aligns with the rudder hinge line

But your rudder hinge line is not perpendicular to the bottom of the fuselage???

I have seen one guy with a separate servo to run the tail wheel

After looking at the Tower Trainer, I would use the Dubro bracket.

Make a plywood shim to angle the bracket to where its pivot axis is the same as your rudder hinge line. Make a new wire for the bracket that goes up and is epoxied into the rudder

w8ye

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On my main gear I used 1/4-20 nylon wing bolts to hold the gear. I drilled and tapped threads directly into the maple plywood without using blind nuts. If I hit the ground hard it will shear the bolts off and not tear out the bottom of my fuselage

After the first pisture of the LT40 ARF was taken I changed the wing to bolt on. I drilled two holes in the F2 bulkhead to receive two dowels that were epoxied into the wing. The wing was reinforced underneath inside the fuselage where you cannot see it.

I added maple ply at the rear for the two nylon wing hold down bolts. There again the threads were tapped directly into the plywood

dash008

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I like how you did the plywood... Did you just glue it to the bottom of the fuse?

bingo field

http://www.rcuniverse.com/forum/m_21...dragger/tm.htm

Here is one I modified a while back.

w8ye

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I removed the covering and epoxied the plywood to the plane. That picture was taken last year this time and last April- May-June I flew the plane a lot and so did my son and son in law. I never had any trouble with it.

You can sand the plywood into a wedge if you are careful

The SIG LT40 ARF is 10 years old. I changed it to a tail dragger last year

dash008

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That's a nice looking plane! How do you keep it so nice? What size 4-stroke is that? I want to get a more powerful engine for mine. I have a OS 40LA on it and it is pretty gutless. I recently bought a new 46AX for a stick ARF I was putting together. I couldn't wait to try out the new engine so I put it on the Tower Trainer to try it out. WOW!! what a difference! So much Power!! The only thing I didn't like about the AX on the trainer was it would sink like a rock when powered off... I had to add a lot of weight to the tail to get it to balance. My gentle gliding touchdowns with the 40LA became ungraceful "plop-downs"! The power was great though.

I guess I'll put the 40 back on the trainer for the time being, but I would really like to find a slightly more powerful engine for it that maybe doesn't weigh as much as the 46AX. Was thinking maybe a 46LA?

dash008

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Nice looking work Bingo... Looks like we used the same main gear. What size tail wheel did you go with? I have both a 1" and a 3/4" and I fly off grass too. The hobby shop I checked today had a 1.25" wheel as well.

w8ye

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my LT40 has a OS 52 four stroke. It has plenty of power. The plane used to have a Tower 46 for 9 years. That was too much power if you opened it up.

You will really like the os 46LA they run pretty good and will be about right for the plane

bingo field

I used an Ohio Superstar Products Medium tailwheel. I got the larger one because I fly off grass. This thing has a ton of ground clearance, and the slightly larger wheels make ground handling a piece of cake. I included pictures of the tailwheel steering, and someone else in that post put in a picture of how they did theirs. I believe after modding this thing like this, it just flies and handles much better. You can really push the envelope with it, and even touch n goes are a little more fun when you don't let the tail settle. It's also a challenge to see if / how long you can keep it on just one of the mains without touching the other to the ground.

Jacked69

Hmmm wow you just gave me a new idea for my alpha 40, even though I head the alpha 40 has some of the strongest gear of any trainers but I just use my alpha now for winter flying and just screwing around, so I want to put a larger engine in it, and now after reading this post am no doubt converting it to a dragger, never thought of that. Is it a big job to do? Jason

Daren71

I converted a LT-40 to a tail dragger last winter. I used a Dubro tail wheel kit, medium sized, and did a pull pull system on the tail wheel steering. I think I used a Sullivan pull-pull set-up mounted to the rudder servo. The only other fuselage mod I made was put a piece of 1/4" plywood into the very aft of the fuselage to support the tail wheel assy. On this plywood I mounted 2 blind nuts to mount the tail wheel to the fuselage.

All worked well, ground handling was great and it flew OK. I put a used Saito 56 on it, and I've still got some issues to deal with it. I had 3 dead sticks in a row. On the last one I damaged the gear mounts, and had to re-do the lower fuselage and blind nuts there. Hopefully I'll be able to sort out the engine this spring. Daren

sawdust

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This trainer flies very good with a 46 AX with an 11 x 4 prop. You might try that before switching engines. An 11 x 3 might be even better. But I have not tried the 11 x 3.

Todd

w8ye

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I've run the 12-1/4 X 3-3/4 prop on the Tower 46 and on a OS 52 four stroke. that will slow your plane down some.

dash008

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When I had the 46ax on the Tower Trainer I was using a Master Airscrew 11x5 and it was plenty fast. I have since installed that engine on my GP Big Stick (and I have yet to clean the mud out of it and make sure it's ok ) So the only engine I have left is the 40LA to go back in the Trainer. The 40 flies it fine, but it is kind of uninspiring. One of these days I'll get a bigger engine for it, but my priorities for the time being are to finish this tailwheel conversion, and then fix my Big Stik. Plus I got a Hanger 9 field box for Christmas so I need to put that together as well!! That should keep me busy for awhile! With a wife and three kids I have limited time to work on this stuff. Thank God for ARF's!

bingo field

If the grass where you fly isn't too long, you may want to try some wheel pants to dress it up some, and I believe that it helps to reduce the drag from the wheels. This is my Tiger 60 with U Can Do wheel pants some hobby shop had in stock while I was looking for some. I didn't even paint them.

dash008

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I decided to go with the Sullivan Tailwheel bracket. It looked much more substantial than the Dubro. I liked that it had a spring gear wire rather than just a straight wire coming down. I cut a small triangular shaped block out of 1/8" ply and installed the blind nuts for the tailwheel bracket, then epoxied it to the bottom of the fuselage. I went ahead and painted the whole piece with 30 minute epoxy to protect it from oil and because it gave it a varnished appearance.

I drilled a hole up thru the elevator and into the rudder and then epoxied a piece of the old nose steering pushrod into the rudder and bent the other end to fit into the tailwheel. I had to cut a pretty big hole in the elevator though, so that the rudder and elevator both would have freedom to move. I hardened the edges of the hole with CA and everything moves freely, but I'm not entirely satisfied with this method... I didn't anticipate needing the large hole in the elevator before I started. I also worry about the durability of this method with the rudder taking all of the steering load... While everything seems really solid now, I'm anticipating durability issues after a few taxis in the grass.

If I have problems I'll do what I should have done in the first place and run a push rod from the rudder servo back to tailwheel... Now that I look at it, I think this would have been easier than connecting it to the rudder as there are already holes drilled in the bulkheads and cut into the bottom of the fuse for another pushrod tube to run back there. You can kind of feel it under the covering.

Well anyway, I guess I'm done for the time being. Can't wait to try it out!

I do enjoy tinkering with these planes, and I realize now there is very little I can do to mess it up so bad that it can't be fixed later. For instance when I epoxied the pushrod into the rudder it turns out I pushed so hard I pushed it all the way thru into the vertical stab! When I came back to it the next day of course the rudder would not move... A little dremel work and it was good to go.

If I decide I don't like the pushrod in the rudder, I'll just snip it off, patch the hole and try something else! This is giving me confidence to tackle the broken stik fuselage.

w8ye

My Feedback: (16)

I thought about hooking into the rudder for a year or so before I finally did it for the first time in a conversion around 5 years ago.

But I've never had a single failure as a result.

jeffie8696

I had an OS .46LA and it was not an awe inspiring powerhouse either. There are a lot of engines out there that will out perform the 40 LA . I have heard the LA40 is one of the best .25 size engines around though. [sm=lol.gif]
Weight if a major factor with the Tower Trainer from what I have read(and you have seen) so keep that in mind. You may look at the Thunder Tiger GP42, it is one of my favorite engines and should out run the 40LA by a good margin and only weighs 13 oz. complete with muffler.

dash008

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Thanks for the tip. I will check that engine out... Like I said before, I like the way the plane takes off and flies with the 46AX, but not the way it glides and lands. Would like to find a happy medium...

jeffie8696

I also had a great running GMS .32 and can't help but imagine it or a larger one would work well(and the price is right). Don't have any weights for them though. The published weights may or may not include the muffler so I only use my own scale since it would otherwise be moot.