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SIG Kadet LT-40 Build - My first proper build!

Warts and all build by a beginner - I don't know how this is going to turn out!!

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Nu Me 122/07/2019 19:36:06
51 forum posts

Hi Percy - The torque rods are brass sleeved however, it looks like the end of the rod just goes into a hole drilled into the aileron. No sleeve. Note that the fixed part of the trailing edge needs to be cut for the rod.

If I offer up a servo into the wing, on the premise that I was going to go off piste, it does fit. I would need to get another servo and some other bits but that is no real hardship. Given it's my first build should I just go for the twin servo make it up as you go along? Would I just connect the servos together electrically and have on push and one pull? Y electric cable cable?


Edited By Nu Me 1 on 22/07/2019 19:36:37

Percy Verance22/07/2019 19:49:58
8108 forum posts
155 photos

Hi again Nu Me

Cutting the grooves for the torque rods can sometimes be a little fiddly, but get it right and it will all work ok. The trend for some time has been to fit a servo in each wing half, usually about halfway down the wing. It can make for more precise control, and can give an element of redundancy should one servo fail (it's never happened to me).

You can connect the two servos with a Y lead, but in so doing you'll lose the ability to trim each servo individually if it becomes necessary. You'll find that these days most newly sold radios will have a facility for operating two servos in a wing (using seperate channels) without using a Y lead. And it's usually preferable to do it that way if possible. I wouldn't worry about it too much just yet Nu Me. Get both wings and all the other bits built, and then give it some thought......



Edited By Percy Verance on 22/07/2019 19:52:54

Alan Gorham_22/07/2019 20:54:47
1153 forum posts
133 photos

If I was you at the bottom of the learning curve and wanting to get a model built, I would just follow the plans regarding aileron actuation. It is a tried and tested solution and the supplied torque rod hardware looks good to me.

The more changes you make, the more things you have to figure out, the greater chance you have of losing motivation and actually finishing the model.

I use a single servo with torque rods wherever possible as it's cheaper, simpler, less to go wrong and many of the benefits that people would have you believe with a 2 servo set-up are not that much of a benefit.

I've got several models here that are many years old and rest assured that decent torque rods won't wear out or get sloppy.

Don Fry22/07/2019 21:08:42
4408 forum posts
52 photos

Alan is right. Stick to the plan. It's a bit old fashioned, but it still flies, and the dangers of off piste building are not good.

Nigel R23/07/2019 06:54:40
3407 forum posts
524 photos

Agree with Alan and Don.

Torque rods work prefectly well.

I will use them over a two servo install as I find they are quicker and easier than doing two servos. As Alan says the benefits of sticking in two servos are not that actually that beneficial for most models. There are exceptions of course but a trainer is not one of them.

RC Plane Flyer23/07/2019 09:10:13
676 forum posts
19 photos

Hi Nu Me. Appreciate your skill levels and comments made by others that may put you off a little re your torque rod installation. I have just aquired a Chris's Foss kit built Acro Wot with torque rod set up fitted and after years of flying 2 wing servo set up I could not tell the difference when I got it into the sky, I am pondering of going with two midi servos in the servo hatch or even the not so common large circular servo arm cut to give the more up than down set up just to settle it down on respone to inputs when on take off. Anyway continue with your build

GrumpyGnome23/07/2019 12:01:58
513 forum posts
145 photos

I took a 'hybrid' approach with my sadly dead Wot 4 ..... 2 aileron servos using 1 torque rod each, both in the wing centre section. Best (or worst) of all worlds!

Having said that, I agree with previous posts - follow the plan for the first build.


Edited By GrumpyGnome on 23/07/2019 12:12:02

ASH.23/07/2019 14:04:45
323 forum posts

Hi Nu Me, I would always go with separate servos for ailerons trainer or not. Many advantages, you can use them as flaperons (both ailerons down) or better still - spoilerons (airbrake, both slightly up). It's more fun to fly slow and low as you progress. Also, you can just glide, my 3kg high winger can stand still in a stiff breeze engine on idle. So much fun. Also, you can programme in differential if you want.

It shouldn't be difficult for you at all with your skills. Just position them correctly.

Ps. Going off piste can be quite dangerous.. but not in this case.. 🙂

Edited By ASH. on 23/07/2019 14:10:27

Alan Gorham_23/07/2019 15:03:27
1153 forum posts
133 photos

Reasons not to use 2 aileron servos when you have all the materials needed for 1 servo:

1. You will have to source and buy an extra servo,

2. You will have to source and buy servo extension cables and fit them in the wings. If you have already built the wings and not made provision for a servo lead to route through the ribs that could be interesting.

3. You will have to source and buy linkages and horns.

4. You will have to design servo mounts to hold the servos into the wings and access hatches to fit and maintain the servos.

5. You will possibly have to source and buy extra materials to make the hatches and fasten them to the wings.

6. You will have to learn to program 2 aileron servos into your transmitter.

7. A trainer (and most importantly a trainee pilot) will not benefit from flaperons or spoilerons. Learn to fly a basic 4 function model well. Yes, in a years time when your trainer is "passe" then by all means use your new found skills and experience to either build a new wing with 2 servos or modify the old one.

Just not worth it.

ASH.23/07/2019 15:21:53
323 forum posts

My thoughts on this.. If you are building from scratch then it's going to be a 'keeper' so why not have all the 'bells &whistles' in place now to use later. Your first model is like your first love..! Never forgotten and ways thought of fondly... laugh

Alan Gorham_23/07/2019 15:29:51
1153 forum posts
133 photos

And if the wing gets damaged in a crash while learning to fly, more repair work.

Don Fry23/07/2019 15:46:55
4408 forum posts
52 photos
Posted by ASH. on 23/07/2019 15:21:53:

My thoughts on this.. If you are building from scratch then it's going to be a 'keeper' so why not have all the 'bells &whistles' in place now to use later. Your first model is like your first love..! Never forgotten and ways thought of fondly... laugh

Absolutely right, a great learning exercise. Best not taken too seriously.

Peter Miller23/07/2019 16:10:20
10525 forum posts
1246 photos
10 articles

Personally I normally use one servo in the middle of the wing. I do tend to tun pushrods out to bellcranks but forget that as it is just my way.

On this model go with the original design set up. IT works well.

They try to tell you that two servos means that if one servo packs up you still have one.

I can tell you that if you only have one aileron working you are in dead trouble. Trust me on this..

With the single servo operating pushrods you can't have that problem.

Nu Me 123/07/2019 16:42:00
51 forum posts

Well thanks for all of the comments and suggestions. Its been a quite a lively debate! I don't think changing the plan is beyond my scope of time or expertise. It isn't unaffordable either. I think it would be quite interesting to build it with twin servos.

At the moment I still haven't decided which way I am going to go. Yes, it is my first build but I am not phased by the thought of doing it. I am almost at the stage where I will have both wings build. After that the wings are joined and then the Instruction Book have the Ailerons as the next steps. I could leave this and start the fuselage - until I am certain which way I want to go.

Don Fry23/07/2019 17:42:49
4408 forum posts
52 photos

Nu Me, killer response. You, if you persist in this game of blood, you will break enough airframes to learn a lot of techniques. Don't waste passion farting about with altering the design of a proper kit.

Get this one up, and down once. Then do it again. That is the goal.

We respect your desire to build the airframe. That is actually a really good decision, because ARTF stuff looked good out of the box, but it ages in seconds, and falls apart, and is ultimately an underachieving technology. You are paying a lady in VietNam to gain knowledge you can learn, and she is interested in other goals than the integrity of the airframe.

And crack this one, you can crack another one. But get it built, don't mess about.

Nu Me 123/07/2019 18:21:47
51 forum posts
Posted by Don Fry on 23/07/2019 17:42:49:

"...And crack this one, you can crack another one..."

Thanks Don.

I am already liking the look of this Here.

Percy Verance23/07/2019 18:52:23
8108 forum posts
155 photos

Oooh, steady on Nu Me, that's a bit ambitious. Realistically, that is something like a 5th or 6th model. WW2 warbirds are not normally noted for their handling finesse, and a fair bit of piloting skill is usually required to ensure success. The build would of course be do-able, but it will be more involved than the Sig trainer, with more complex areas of contruction. It's do-able, but not for a while.....I'd gingerly suggest 2 to 3 years?

Don Fry23/07/2019 19:40:00
4408 forum posts
52 photos

Nu Me, Percy is not normally noted for being subtle. But here he is.

That is a nice plane. It's going to cost you couple of hundred hours to make. You MIGHT do a couple of hours before something causes it to hit the ground. If you are happy with this ratio, carry on.

I am sorry to pull you back, but the path to the P47 is not easy.

I have seen a lot of ex flyers, turn up with a trainer, dreaming of a warbirds, and start building/buying to the dream, and when they have a wrecked model, think/say, I've spent my money/time/passion, and I've got nothing back here.

Your next model is an aerobatic trainer. With the same motor. That motor is good for thousands of flights. A clue.

Edit. What I'm trying to say, those of us who persist, do so because we are bloody minded enough. Break an airframe, build another. We all dream. But you have to build them faster than you break them.

Edited By Don Fry on 23/07/2019 19:51:28

Nigel R23/07/2019 23:12:43
3407 forum posts
524 photos

What Don said.

I would add. The trainer is a moped. The warbird, a fireblade.

The moped should be cheap, simple, easy, and teach you the ropes. Make it like the instructions say. It is s tool to teach you the game.

Plenty of scope for building how you want later in the game.

By the time you are ready to ride the fireblade, you will know whether you still want the fireblade - or if maybe you actually want a blackbird instead now you know your mind better.

David Davis24/07/2019 05:14:13
3532 forum posts
640 photos

I'd heartily recommend a WOT 4 as the second model Nu Me 1. The Mick Reeves Gangster has its afficianados and is by all accounts a superb kit and flyer, so that could be a good second model too. As for the third model, an Acrowot or one of the classic patternships would take your flying to the next level after which you'd be ready for your P47.

Of course there's no reason why you shouldn't buy the P47 kit and build it while your flying improves with intermediate models. Even the real P47 pilots went from the Stearman to the AT6 Harvard before they went on to the Thunderbolt.

Edited By David Davis on 24/07/2019 05:43:36

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