A Different Peanut

[kittyfritters]

With a Peanut contest coming up I decided to build one of the Herb Weiss minute models as a Peanut. Now, why I thought this was going to be a good idea is beyond me currently. I chose the F2A, Brewster Buffalo, as the one to build. The first thing I found was that despite their small appearance and having "complete" plans on one page of a model magazine (More about the word "complete" later...these are 1930s plans.) they are somewhat larger. I scanned the plan into Inkscape, traced the parts and laser cut them.

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The easiest thing to start with was the cowl...it's round. Of course, I made one small modification, making the cowl removable for easy access to the rubber. I use trapezoidal keys whenever I can. I glued the cowl rings together, cross graining them, chucked the assembly in my Dremel drill press, and smoothed it out with a sanding block in a few seconds.

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[kittyfritters]

I intended to build it as described in the magazine article but then I read the article. When you first look at the plan the fuselage appears to be built on a crutch. I have no problem building a fuselage on a crutch, I've even designed a couple that way, but that's not exactly the way he did it. According to the instructions you build the wing first, glue formers to the leading and trailing edges, add the 1/8" X 1/16" crutch and add formers to the front and rear. I suppose it was supposed to be a self-jigging construction method built while holding it in your hand however, it occurred to me that I would have to cover the wing first (not mentioned in the article or on the plan) or I wouldn't be able to cover it and also that It wouldn't be hard to build a banana shaped fuselage this way. I decided to build it on a conventional crutch and cut the cross pieces out after I had the stringers on. The plan calls for another 1/8" X 1/16" stringer to make the edge of the cockpit with the top and bottom stringers being 1/16" square ("keels"?) and the remainder of the stringers being 1/32" square bamboo. The bamboo callout is to make the fuselage strong enough to run into a wall, no, really! Read the article. I decided that 1/32" square balsa would be enough.

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When I got it together I decided that it was a bit heavy for such a small model so I decided to redesign it in my usual half shell style with 1/16" square keels and the 1/32" stringers. It was easy to simply cut the formers in the drawing and re-cut them on the laser.

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I then proceeded to build it using the half shell method.

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[kittyfritters]

As you saw in my last post I changed the design to half former construction and cut new parts. I pinned down a top and bottom keel of 1/16" square. Then I pinned down right angle tools to the plan at the former positions. Working from back to front (to keep from trapping a right angle tool in the back of the fuselage) I glued in the half formers using the right angle tools to keep them perpendicular to the building board. I changed the 1/8" X 1/16" crutch to a 1/16" square side keel. I added the side keel, carefully then removed the last right angle tool. Herb had a 1/8" X1/16" master stringer that defined the edge of the cockpit and I changed that to 1/16" square also.

Now to get to get the other half on. This is where flat craft sticks and small clamps come in. For a model this small I split some craft sticks in half lengthwise. I apply a stick to one of the formers already glued on with a clamp, then put the other half of the former in place, clamping it to the craft stick, check the alignment, and apply glue. This technique works with any keel and half former model that doesn't have self jigging interlocking parts.

With the other side keel on I'm not building a banana and all I had to do was put the 1/32" stringers on. I built the key on the back of the cowl and checked the fit.

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[kittyfritters]

I got back to work on the wings. I did do a slight redesign but it is still going to have bamboo wing tips as the plan called for. This is not my first experience with 1930s building techniques.

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As you can see this model needs substantial dihedral.

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The obligatory "bones" shot. The tail feathers are 1/32" sheet as on the original plans.

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I used to bend bamboo around an incandescent light bulb but it's all LED around here now so not enough heat. I didn't want to have an open flame on the work bench but I hit on the idea of setting my heat gun on it's back on the bench and bending the bamboo around the nozzle. The picture is just for illustration, you have to use both hands while bending.

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[kittyfritters]

These are the skins I printed for the wing and stabilizer. This was relatively simple.

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The fuselage, not so much. I had to print several bond paper test images to test the fit.

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This is the smallest model that I have wet covered.

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The wings weren't a problem although since I based the skins on my NoCal F2A skins they come out looking cartoonish on a dimensional model. So, I set up to do the fuselage

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[kittyfritters]

The first side went on easily enough.

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The second side was more work. I took it outside to mist it with Krylon.

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Like most 1930s plans the patterns for the canopy were something you had to work out for yourself.

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This is what it looks like finished. Now to see if it will fly.

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I took it to the OFFC meeting at the end of the month.I only had a few minutes to trim it because there was a P-18 contest that morning and the time I had was from the end of the contest until we had to give up the gym. Fortunately, it flew stabily from the start. Since it is rather draggy ( I think that I should have built it gear up.) it does need more power, so I will have to use 3/32" rubber instead of the 1/16" I had in it. I got flights all the way the length of the gym but it doesn't want to turn. I decided to try try trimming it outdoors at the Black Sheep LoCal contest on Sunday morning.

I took it to the LoCal contest (Finished second with my 15 year old P-51.) to see how it did outdoors. I put some larger, 3/32", rubber in it. It was a bit tail heavy with that rubber but I didn't have any stall/spin crashes and it's still in one piece. A little clay in the cowl fixed the tail heavy problem. With enough winds in it to get a long flight it has trouble handling the torque on launch but if the rubber is backed off it won't climb. I' thought to try a smaller prop. There was a slight breeze and it had some trouble with penetration because it is rather draggy. I think I should have built it "gear up" even though our indoor Peanut contests have an ROG bonus.

[kittyfritters]

I clipped the gear off ot it. Only saved 0.84 grams but the reduction in drag was stunning. However it does look cuter sitting on the gear.

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I took it to the OFFC meeting least Wednesday and started some low powered trimming flights. When it was trimmed to turn comfortably in the middle of the room it would fly for a while then spin in https://www.youtube.com/watch?v=LXA9I3feqLo but, if I opened the turn, it took the whole width of the room to circle. https://www.youtube.com/watch?v=EGkCL5noPAk I was afraid to put enough turns into it to get it to climb in the gym so I packed it up and flew another model. On the way home it occurred to me that maybe it wanted to turn left so I'll try that next week.