PylonWorld
Posts: 1346
Joined: 12/29/2001
From: Monroe,
NC, USA
Status: offline
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Yes, the wing saddle will be cut out. I have the wing molds for Jerry Small's Swee' Pea (that were done by Norm Johnson), and to start with that is the wing that will be used.
I didn't put a wing saddle in for two reasons: 1) I can move the wing to change the moments to fine tune the performance, 2) I can use any wing on it. Since the Swee' Pea wing is a 52" span with a 10" chord and 5.5"-6" wing tips, I wanted to be able to create a 56" span wing if the 52" wing slows down in the turns too much. Adding a saddle is a little extra work, but nowhere near as much as carving a new plug, or trying to move the wing around or change the wing with a saddle in place. When I've decided on the wing location and type, I'll lay up some thicker parts to use as male molds, and will add the saddles and make new molds.
There is a possibility that I will actually build some as one piece planes. Harder to transport, but the trim doesn't change from one wing mounting to the next. I may even try plug in wing panels.
the 2 oz plus 6 oz is plenty for the rear. Because of the curviness it actually is quite rigid torsionally. I have used 12K and 50K CF tow as stringers and formers with good results. The 50K takes a lot of resin to wet out though. The front has an aditional piece of 6 oz, so there is 14 oz from the rear of the saddle to the cowl ring. CF 6oz could be used up front for a steel rigid front end. However, CF dust is very dangerous, and since some grinding will have to be done on the wing saddle, I won't be making any for myself that way.
I know of one Q-40 manufacturer that uses 2 layers of 4 oz and a 4 oz doubler. I don't like this because it results in pinholes. I'm going to try 1.4 oz for the first layer, because it conforms to curves better than the 2 oz that I'm using, and should reduce pinholes even more.
Stay with epoxy for the parts for several reasons:
* The pot life of polyester vinyl resin is the same as the working time. If is goes off in the pot in 15 minutes, you may have 16-17 minutes of working time. With laminating quality epoxy, you can mix small batches, and as you need more resin, you mix more batches. The thin film set time for epoxy is usually 2-6 times the pot life. So a lay up is much more relaxed. I've laid up between 1000 and 2000 fuselages, wheel pants, cheek cowls, and other parts with polyester, and the epoxy lay ups are easier. The viscosity of the epoxy resin is important. West System 105/205 is too thick for laying up model parts. 206 hardener is much thinner and lays up far easier, plus it has a 20 minute pot life.
* Polyester shatters in the thicknesses we use on model parts. Polyester never really finishes curing. It gets more brittle with time. If you look at some well used planes with polyester fuselages you will see cracks.
* Epoxy does not bond to polyester. When installing firewalls, servo trays, etc, you have to scuff the polyester down to the fibers to get a good bond. Scuffing epoxy is also wise, but epoxy will stick to epoxy.
* I don't like using polyester on carbon fiber. It can be done, however, I don't like it. I don't feel that the poly penetrates the CF fibers as well.
I can't give you the weight, as I've given away the parts that have been produced so far. I think it was 4 ounces or less for the half.
Hey Ed, can you weigh that half of the Hughes H-1 I sent you and post the weight and some comments.
< Message edited by PylonWorld -- 10/23/2003 10:14:08 AM >
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All Forums >> RC Airplanes >> Pylon Universe - RC Pylon Racing >> QM-40 Racing >> Hughes H-1 Racer for Q-40 
Hughes H-1 Racer for Q-40 - 
Hughes H-1 - 
So if anyone would be interested in receiving one, email me with your email address and mailing address. 
