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Trainer Frustration


RonSpencerUK
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Hi All
 
I can't be the only person to lament the dreadful piano wire u/c legs supplied on the majority of trainers.
When learning, one is going to make some pretty rough landings so why have legs that:
a)bend out of shape really easily
b)are a pain to bend back into shape
c)are very much weaker and more prone to bending after a) and b) have occurred?
 
I see that the WOT trainer has 'springy' looking legs. Are they better than the wire?
 
Can anyone suggest a better set of legs for my Boomerang?
 
Thanks in advance.
 
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Trouble is, you bolster the U/C up and force will find the next weakest spot, normally the fuse. My advice is that it's easier to straighten the wire that re-build the underside of the fuze.
I have wire u/c on my Arising Star and Calmatos. I've taken to building a small jig to straighten then out quickly at the field.
As for the Wot, can't help there.
Good luck.
 
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Hi Spice Cat
I take your point about 'sacrificial' weakness, but Olly Giles has the right approach surely. Tough, springy legs with the airframe protected by sacrificial retaining bolts sounds a much better solution to me.
So, any ideas who sells such things in Boomerang size?
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Phil is right I think. TBH a good piano wire U/C is probably the optium arrangement for a trainer - the problem is so many trainers seem to U/C made from "cheese straws"!
 
If the piano wire is the puckker item then it is very springy and, short of really ramming it into the ground, you wont deform it easily.
 
The nylon bolt U/C seems a good idea on the face of it. But there are some problems in practice.
 
1. Nylon bolts are quite a lot stronger than you might think - and ARTF trainers are alot more fragile than might think! Especially as their U/C mounting points aren't designed for a bolted on U/C. Result the U/C plate is still weaker than the bolts, the bolts don't break and the plate rips out.
 
2. So next up you start part sawing through the bolts to make a weak spot. Result - you pull off a greaser of a landing but unfortunately hit a tussock of grass the wrong way and the U/C falls off!
 
My advice would be stick with the piano wire - but get some of the "real stuff" for the mains and a replacement pre-bent springing unit for the nosewheel.
 
BEB
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Another approach, many ARTF's come with very small wheels. If you fit larger wheels they will roll over clumps of grass, rough spots on runways better.
 
Obviously they won't make much difference if you hit the ground at 45 degrees, but that is not counted as a landing!
 
A lot of models are aimed at the American market where runways generally are smoother.
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I agree Ron, stick with Piano wire and rather than changing your undercarriage, practice your landings with the sole purpose of not bending them! You never know, it might actually improve your landings and having a positive effect.
I used to have to bend mine back all the time, strangely enough, i don't seem to need to do that anymore!
What i do know though, is that if i hadn't had wire, i would have completely written off the underside of my model on a few occasions.
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I can never understand why they always use trike gear. They are useless on anything but perfect surfaces. Especially when combined with the bits of wet spaghetti laughingly call wire supplied by our oriental er...friends.
 
When I get someone to train I make them convert their trainer to a tail dragger. After that they can take off and land on ploughed and harrowed field and stubble fields quite easily.
 
My normal conversion is to throw away to nose leg and move the main gear forwards. Fit a ply plate and two dowels and hold the U/C on with elastic bands. I use either a dural U/C or one of those wire ones as sold by J Perkins stockists.
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