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AMR TRAINER 20

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AMR TRAINER 20

Old 06-14-2011, 07:28 AM
  #51  
Cherokee Flyer
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Default RE: AMR TRAINER 20

CanDo;

I like what you did on the wing; but with a 8+ lb airplane, I will be using metal bolts. As for the landing gear, the need to make the gear easy to ship doesn't carry much with me, a two piece gear will load up one side of the fuse if you happen to land funny. I think I will build a plate to carry across the gap. Did you have any fit issues with the dowel and the holes cut in the control surfaces?

L.

Old 06-14-2011, 08:20 AM
  #52  
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Default RE: AMR TRAINER 20

Cherokee,
There is a problem with using metal bolts here for the wings. The wings bolts screw into metal T-nuts. If you use a metal bolt  you will risk the bolts vibrating loose in flight. The nylon bolts won't vibrate like metal bolts will. The nylon bolts are strong enough to secure the wing to the fuselage.

Ken
Old 06-14-2011, 09:15 AM
  #53  
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Default RE: AMR TRAINER 20

I agree with Ken, I have 1/4x20 nylon bolts on my 10lb Sr Telemaster and my 12 1/2 lb BUSA Pup with no problems. Sometimes old nylon bolts (and props) get brittle, it's probably a good idea to replace them every year or two when you change your fuel line. I had the head pop off of a older nylon bolt when the plane was just sitting in the pits.
Old 06-14-2011, 10:47 AM
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Default RE: AMR TRAINER 20

Does this mean that I should not have been using metal bolts on my wings for the last 45 years!!

L.
Old 06-14-2011, 11:08 AM
  #55  
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Default RE: AMR TRAINER 20

Nope, the great thing about this hobby is you can have it your way! I've been building R/C planes for ~20 years and model planes for ~50 years, it's all about what works for you. All I'm saying is I've never had a nylon wing bolt fail in flight. FYI, I did use smaller steel bolts in my 19 lb OV-10 Bronco with some blue Loctite, just to be safe.
Old 06-14-2011, 12:54 PM
  #56  
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Default RE: AMR TRAINER 20

Well have the two coats of nitrate dope on the fuse and stab parts. I think I will rig all the fuse controls before I go on to the wing. It is a nice kit; sure like laser cut over "crush" cut anytime! You are right, there are many diffrent ways to do things, and that is what makes this hobby great. My father was a modeler from his teen years; so I grew up with it. I still have his Quaker he built in 1937.

L.
Old 06-14-2011, 02:54 PM
  #57  
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Default RE: AMR TRAINER 20

Passing the hobby on is special; I still have my Dad's "Spirit of St Louis" he hand carved after Lindberg's flight.
To answer your question, the dowels in the elevator and rudder seemed to fit OK, but I secured them with epoxy just to be sure.
Old 06-14-2011, 06:38 PM
  #58  
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Default RE: AMR TRAINER 20



The holes in mine were closer to 7/16"; bit roomy for a 3/8" dowel.

L.

Old 06-14-2011, 07:17 PM
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Default RE: AMR TRAINER 20

The holes were a tad bigger than the dowels, but the epoxy secured everything OK.
Old 06-14-2011, 07:34 PM
  #60  
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Default RE: AMR TRAINER 20

I had the same experience with my kit as well

Ken
Old 06-15-2011, 03:29 AM
  #61  
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Default RE: AMR TRAINER 20

I think mine will get a 1/16" X 1" ply square on each side. That is one place you don't want things to be able to come loose. It isn't like that little bit of drag will hurt!

L.
Old 06-17-2011, 11:57 AM
  #62  
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Default RE: AMR TRAINER 20

The wing tips were a little challenging, so I took a couple of pictures before I covered the wing. The first shot shows all the pieces that make up the tip assembly, plus I epoxied a washer on the tip to balance the wing. The second one shows the lower spars cut flush with W12.
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Old 06-17-2011, 12:58 PM
  #63  
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Default RE: AMR TRAINER 20

While the instructions didn't call for it Ichoose to extend the main spar on the bottom of the wing tip and then sand it down to wing tip edge. I did this to give a little bit of an extra place to seal down the covering material when doing the wing tips.

Ken
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Old 06-17-2011, 01:26 PM
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Default RE: AMR TRAINER 20

One question I have is would it have been better to have a big block of balsa on the wing tips and carve them to shape ?
Old 06-17-2011, 01:27 PM
  #65  
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Default RE: AMR TRAINER 20

Ken, good call. I may add a gusset or two on the top side of the wing tips and a skid underneath, just in case I scuff a tip on the pavement.
Old 06-17-2011, 01:47 PM
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Default RE: AMR TRAINER 20


ORIGINAL: heritageman

One question I have is would it have been better to have a big block of balsa on the wing tips and carve them to shape ?

I don't think so really. While the design looks a bit odd here " in the bones", once it's covered the wings look fine. Idon't see any reason to add anything to what is already there.

Ken
Old 06-17-2011, 04:08 PM
  #67  
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Default RE: AMR TRAINER 20

Hello all,

The way the wing tip was design is very simple and ligth weight. Of course, there are many ways to do the same thing. we choose this way to keep a vintage look even at the wing tip. The top main spar is the one that need to reach the half rib found over the wing tip. I dont think it is necessarry to make the lower main spar longer but it does not affect anything so far and the idea is quit good. And your plane look so good in the air... Ken, have you start doing the training with the plane?

Old 06-17-2011, 04:30 PM
  #68  
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Default RE: AMR TRAINER 20


ORIGINAL: vibi08
... Ken, have you start doing the training with the plane?
Unfortunately we had to postpone the training for this week. With winds 25-35 mph 4 out of 5 days this week we couldn't get out and train the kids. We're going to reschedule later this summer some time

Ken

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