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May 17, 2013, 07:40 PM
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White Fang
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Fulcrum stunter design/build


This is kind of a generic design using ideas and shapes stolen from many other planes. I always liked the nickname given to the Mig-29 "Fulcrum", it has a solid sound to it, so even the name was stolen.

690 sq. inch wing and this one will use an ST60 for power.

More to come, Bill
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May 17, 2013, 10:15 PM
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I can't get a good image of the entire fuselage side drawing but here it is in three pieces. Kind of like a 60-size Nobler, it's 7 inches tall at the canopy.

Edit: Took a new picture of the plans, let's see if it's any good.
Last edited by WBE; Jun 08, 2013 at 02:25 AM. Reason: added new image
May 18, 2013, 01:43 AM
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stuntflyr's Avatar
Nice crutch, and model Bill.
Did you ever see pics of Windy's Mig or F-16? Cool ST 60 models.
Chris...
May 18, 2013, 06:47 AM
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Keep us posted Bill. Looks like one real cool plane.
Alf
May 18, 2013, 08:17 PM
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Quote:
Originally Posted by stuntflyr
Nice crutch, and model Bill.
Did you ever see pics of Windy's Mig or F-16? Cool ST 60 models.
Chris...
Only saw a couple pics from a magazine a long time ago, that Mig Sweeper was huge as I recall.

Got a jump on the fuselage today. First thing to do was lay out and cut the 1/16" ply doublers. One of the advantages of having the wing made ahead of time was that I could now use it to trace an exact hole for the fuse sides and doublers.
May 18, 2013, 08:28 PM
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Quote:
Originally Posted by alf.g
Keep us posted Bill. Looks like one real cool plane.
Alf
Will do Alf, thanks for watching.

The chord of the wing is ~3/32" less than the root where it exits the fuselage side. So the hole was moved back by that amount, kind of splitting hairs here but as Tom Dixon once said 'You can't go too far with your accuracy when trying to please the stunt gods'.

The best way for me to negotiate the small radius turns at the front and rear of the wing when cutting out the ply is to simply drill the appropriate size hole. At the leading edge I used a 1" forstner bit and at the rear a 3/8". The top-rear corner for the cowling is 1/2".
May 18, 2013, 08:32 PM
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Now that the hard part is done it's just a matter of hacking out the excess wood and cleaning up the cuts with some sandpaper. They turned out better than hoped and they even match the plans.

More later, Bill
May 18, 2013, 11:19 PM
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One of the problems you get when using a generic wing is that it won't have the "perfect" dimensions. When I drew up and built it 8 years ago I was thinking something in the neighborhood of ~725 sq in.. Today that seems awfully big, 650 sq. in. would be more in line with modern practice.

So, in an effort to get rid of some of the excess fat I cut 1 1/2" off each tip, losing about 40 sq. inches. This reduces the span to 59", also good.

So new span-59" area 685 sq. in.

It hurt a little cutting that wing I must admit.
May 19, 2013, 02:53 AM
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Looks good to me!
Did you cut the foam wing yourself, or is it from Bob Hunt? (I suppose there are others who will do that for you.)
May 19, 2013, 05:13 PM
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Neat craftsmanship, love the look of that hollow foam wing, lightweight, strong, nice thick airfoil. Looking forward to seeing the finished product.
May 19, 2013, 06:11 PM
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Thanks fellas, I built those wings a few years ago with the idea that I'd design a fuselage and tail for it in the future, just wished I hadn't made them so big.

Note to self: Make the foam cores smaller next time.

Here are the low-tech cutting templates, there's another set for the inside (hollow) cuts.
May 19, 2013, 06:20 PM
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Tried a different method of gluing the ply doublers on this time. The balsa sides will be trimmed after attaching the doublers. Thought this might be easier than trying to cut the balsa side and the doubler to exactly the same size, then trying to get them aligned perfectly for gluing etc. was careful to mop up all the excess epoxy that squeezed out.
May 19, 2013, 06:24 PM
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Sorry, the device I'm on today (wife's IPad ) only allows one image per post.

Anyway here's the weight piled on until the epoxy cures. Those blocks are hollow and filled with lead shot, they're about 10lbs. each.
May 19, 2013, 06:27 PM
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Mixed up 6 grams of epoxy in the cup and ended up with about 1 grams left over so added 5 grams of glue per side.
May 19, 2013, 06:31 PM
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With the glue curing on the fuse I laid out and cut 4 ,one inch thick blocks for the wing tips. The tips are 2" thick.


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