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Another Sig Kadet LT-40 build.

Old 09-29-2011, 02:30 PM
  #101  
GaryHarris
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Default RE: Another Sig Kadet LT-40 build.

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Old 09-30-2011, 03:43 AM
  #102  
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Default RE: Another Sig Kadet LT-40 build.

Scratch that. Keep the servos whey they show them to be and cross the outer tube from the left side of the plane and exit on the right side for the rudder.
Old 10-04-2011, 08:57 AM
  #103  
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Default RE: Another Sig Kadet LT-40 build.

I have a build LT-40 that uses the rubber bands, how easy would it be to convert it to the pin and screw setup?  If you could lay out what I would have to do that would be great.

Nice thread seeing my plane come to life.  Thanks for doing it
Old 10-04-2011, 09:26 AM
  #104  
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Default RE: Another Sig Kadet LT-40 build.

See LT-40 Kit Upgrade: Bolt Wing Mount & Tail Dragger
Old 10-04-2011, 02:58 PM
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Default RE: Another Sig Kadet LT-40 build.

Seamus- What landing gear did you use on your lt-40? It looks just right for it.

-rep
Old 10-04-2011, 06:29 PM
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Default RE: Another Sig Kadet LT-40 build.

I went to my LHS and bought a gear that was 14" wide and 4 1/4 - 4 1/2 high (axle hole to flat). Think that it was a Great Planes bit - believe that it was a Dural landing gear.
Old 01-13-2012, 02:49 PM
  #107  
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Default RE: Another Sig Kadet LT-40 build.

Well, I took a little break but now have the plane back on the bench.
Old 01-15-2012, 11:45 AM
  #108  
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Default RE: Another Sig Kadet LT-40 build.

I just picked up a kit yesterday, good to see this thread since I want to make it a tail dragger with bolt on wing. I picked up an OS 52 Surpass 4 stroke to modify my T-34 to glow, but after giving it a good look decided too much work and no guarantee the plane wont fall apart from the vibrations of the motor. So I decided to get a 40 size plane for it, the LHS had a Sig cub 1/5th last time I was there for a good price, but they sold it. The had a new in stock Sig Kadet LT 40, and thought, yep that will work.

Going to put dual aileron servos in as well as the bolt on mod. Might as well since I have a radio that does mixing. What I like about this kit, just needs radio and motor, all else is in the box. If I stick with tri gear, I have everything, but since I want to do it as a tail dragger I will need the main gear, and the tail gear I will use what came with my TF P-51 GE since I put a retract in that plane. Going to cover it in red and white monokote with some Chrome thrown in for fun.

Ran across this 4 part build which is where I got the dual aileron servo idea from.

masportaviator.com/2010/02/26/building-a-wood-trainer-part-two-the-fuselage-and-tail/
Old 01-15-2012, 12:22 PM
  #109  
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Default RE: Another Sig Kadet LT-40 build.

I recently did "covering only" thread on my LT. I clipped one rib off the end and went with a flat wing tip rather than the diagonal standard version.

I originally built my LT-40 "by the book". Then it got converted to a tail dragger and bolt down wing. A comment about it being a tail dragger - keep the weight off it's butt! Be careful with the weight of the wood. If you use light wood for the stab / fin sticks it is susceptible to hanger and transportation rash - mine broke. If it's real heavy - then nose weight to balance. I ended up adding over 16 oz. of weight to the nose. Some was due to a "rebuild" of the stab / fin using a fully sheeted approach. (yea, did a thread on that too). I have since returned it to a tri-cycle gear - more for the benefit of students than my preference.

Good luck with the kit and post some pics.

Old 01-15-2012, 02:07 PM
  #110  
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Default RE: Another Sig Kadet LT-40 build.

I just pulled the manual out, looks like they modified the kit a bit since that link I posted. The builder referred to the center servo and bell crank type of controls. This kit has the links on the ends of the ailerons with a center servo.  I'll go with the kits plans for that one, but still going to bolt the wing on, I hate rubber bands, my Apprentice uses them and I wind up having to retrim it every time I have to remove the wing, but my T-34 stays in trim all the time.

I wonder if I should put a larger tank in, it comes with a 8 ounce tank for a .40 2 stroke, and I am going with a .52 4 stroke.  

Prop size?   12X8 or 11x10?
Old 01-15-2012, 03:02 PM
  #111  
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Default RE: Another Sig Kadet LT-40 build.

I'm not a good source for prop recommendations as my air is pretty thin (nearly 6000').

Tank size? The LT40 flies straight-n-level at 1/2 throttle with a Evo 52. If you exercise basic throttle management 8 oz. works. But this 40 size trainer is really a 60 size trainer. Plenty of room for a 12 oz. tank.

You planning on reducing the dihedral?

Old 01-15-2012, 08:17 PM
  #112  
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Default RE: Another Sig Kadet LT-40 build.

Yes, I dont need all that dihedral, considering the Apprentice wing is nearly flat and I fly that one a lot. Iam even considering going full flat. I like to fly upsdie down a bit so the flatter the better.

As far as dual ailerons, yes or no? Iplan to use my DX6i instead of the Futaba 8FGA for this one since Iwant to use an Orange RX. Ihave a 7 channel RX for my Deweyville Special which is gas and BIG, but only 4 channels needed, so toss up, either use the orange in the Dewey or in the Kadet. Can Iuse the DX6i to mix ailerons? Ihave a spare 12oz tank that Ipulled out of the dewey since Iam going to gas in it, and it is new but for glow only. It has a complete filling connection and tubing with filters, guy who installed it did a very nice job installig it, too bad I cant use it in that plane.

For the wing bolts, do I replace the balsa TE pieces in the center with spruce?
Old 01-15-2012, 08:57 PM
  #113  
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Default RE: Another Sig Kadet LT-40 build.

Well, you're not gonna be impressed with those big ol' flat bottomed wings.

I converted mine to bolts as a modification after it was built and flown for a season. I added 1/8 aviation ply to the back. It would be much cleaner if you use spruce "between the sheets". I added 2 1/4" ply plates epoxied to the fuse sides reinforced with tri-stock. This is enough for either tapping or adding a blind nut - your choice.

Forward connection to the fuse. Look closely at the former at the front of the wing saddle. By itself not sure it will support the added strain. I doubled mine with a floating doubler - it was glued in place during the wing installation procedure - ensuring the the front mount was centered and that the entire wing fit the wing saddle nicely. I used an approach similar to how SIG does their Kadet Senior ARF - a ply bayonet the looks like it's suspended below the wing, in front of the main spar and extends about 1/2" beyond the LE. Do yourself a favor - wait to install the windshield until AFTER you fit the wing.

If you are inclined to do a roll or two seriously consider clipping the wing. I initially built mine by the book. Rudder and elevator authority is good, very good in fact. Ailerons authority? You have GOT to be kidding! A roll took 15 seconds on HI RATES!. Clipped and without dihedral - things will be much better. When you clip the wings you'll also move the ailerons in one more rib bay. That will leave the root of the ailerons about 1" from the fuse. This wouldn't work out too well for rubber bands but with wing bolts - no problem'o ...

When you say "dual ailerons" - assuming that you mean dual aileron servos? That's how all 7 of my planes are set up. Right aileron - AILE channel, left aileron - AUX1. I have a DX7 - not sure how the DX6 mixes the two. Of course, a "Y" harness plugged into AILE works just fine too. No channel reversing needed of course.

Ok - I hadn't converted it from the single aileron servo "yet".


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Old 01-16-2012, 04:21 PM
  #114  
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Default RE: Another Sig Kadet LT-40 build.

How would doweling it from the rear and putting the bolts at the front?   I read elsewhere the bayonet fittings work loose over time and get sloppy.  Then again, if I drop a block across the leading edge similar to how you did yours with two dowels, that might work too.  Could also cut back the leading edge at the fuse 1/4", make it flat and add 1/4" ply to the fuse for the dowels, or even a 1/2" double up the ply.

My T-34 uses the tab type connection instead of dowels, same as you have it, and it is showing signs of weakening. The wing halves join together at that point and there is a crack developing at the leading edge on one wing after only a few flights.  Of course the Kadet doesn't land on its wings like the T-34 so less stress on that joint.
Old 01-16-2012, 05:14 PM
  #115  
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Default RE: Another Sig Kadet LT-40 build.

I have zero experience with bolts up front.

The Kadet Senior had bayonet "release" problems in flight! Not a happy ending. The problem was that the bayonet was too short - just barely inserting 1/8" or so into the former. During flight the really wide wing would flex enough to allow the bayonet to release from its forward contact point. I extended my Senior's bayonet to 1/2" - never a problem.

I kinda like the idea of cutting out and boxing the wing's LE. It could look like a Cub with a skylight above the windshield. My GP Extra 300S build uses that approach for attaching the wing to the fuse. 2 sharpened dowels that fit into 2 larger holes on the forward former and 2 snug floating discs that are glued to the backside of the former after centering / aligning the wing. Since the fuse sides are straight in the LT you could simply extend the fuse sides upward to the top of the wing. You'd have to construct a new former that fits at the wing's "new" forward edge.




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Old 01-16-2012, 06:47 PM
  #116  
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Default RE: Another Sig Kadet LT-40 build.

Yeah, thats the idea I had.  All I need now is time! LOL
Old 01-16-2012, 08:48 PM
  #117  
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Default RE: Another Sig Kadet LT-40 build.

Priorities, it's all about priorities. [:@]

Wished we had the "conversation" before I just redid the LT configuration.

Old 01-18-2012, 06:07 PM
  #118  
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Default RE: Another Sig Kadet LT-40 build.

I stopped by the printers yesterday and got 2 copies of the plans since they are under 40". 2 copies of the 2 sheets, $20. So the originals stay clean, one I cut up for buildong, the other for reference. Wish I could have done that with the Top Flight plans, but they were too big for the scanner. They would have to be done on the digital scanner, put on a flash drive and then printed off a different printer. Would have cost as much as the kit did.

I'm going to sit down with the plans and see what I can do about putting the plywood in on the plans for the pin down and hold down blocks. I matched up the OS 52 to the plans, perfect fit.

Oh almost forgot, I am also tracing the ribs onto a sketch book and going to fli them and make full symetric ribs, Imay build a second wing from scratch flat and fully symetrical and see if I can fly this puppy upside down.

Old 01-18-2012, 06:33 PM
  #119  
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Default RE: Another Sig Kadet LT-40 build.

No dihedral, symmetrical LT40 wing - you are one sick puppy! 
Old 01-18-2012, 08:11 PM
  #120  
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Default RE: Another Sig Kadet LT-40 build.

no, just wacked! My friend said the same thing when I brought it up.  I like to be different.  If I could figure out how to put Corsair wings on a P-51, I would do that too.
Old 01-18-2012, 08:30 PM
  #121  
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Default RE: Another Sig Kadet LT-40 build.

I would love to have a shoulder mounted symmetrical winged aerobatic plane. Know any?



Old 02-18-2012, 05:46 PM
  #122  
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Default RE: Another Sig Kadet LT-40 build.

Well today I pulled out the kit and separated the ribs, weighed them and all the spar wood.  The walkthrough I found recommended weighing the ribs and putting the lightest ribs from outside in, with a rib weighing 4-5 grams at the tip, heaviest near the root.  What he did was put the heaviest ribs on the left wing to compensate for the muffler on the right, but, I am using a 4 stroke, so I will need to see where it comes into play.   If the motor balances out I will build the wings as close to equal in weight as I can. 

The ribs alone come to within .004 kg per side, but the spars, LE and TE, are off by about 3 grams.
Old 10-19-2015, 07:26 PM
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Default

Originally Posted by GaryHarris
Watching glue dry has bored me to death so I moved onto balancing some 12x6 MAS props I had laying around. Still boring. lol

http://www.youtube.com/watch?v=ZJ5E-HyLmOE
That Stevie Ray Vaughan playing in the background sure isn't boring!!!
Old 11-04-2016, 04:45 PM
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Well, did we ever get any finished photos of this LT-40 kit bash?

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