I'm in the process of building a Brodak 38 special with an O.S. 40 FP as a powerplant. Are there any good building tips or flight trimming tips I need to know. Thanks for any advice.
38 special
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If you don't have an incidence meter to set the wings, get one. You'll need one to get the wings aligned. I used slow epoxy & lots of sandbags to hold everything in alignment. Proper alignment is very important no matter what you're building & it's more complicated when the airplane is a bipe. My full-fuse version flys pretty well, though not as well as my flapped stunters. Then again, it's been badly crashed & repaired so it's pretty heavy. I'm sure a light one would be better. It's a really fun sport plane.
Nils
LAST EDITED ON Oct-05-01 AT 12:21 PM (CDT)
I built one in my beginners’ days with the same power plant. It flew very well but I didn't. It lasted 'bout 20 flights and 3 repairs.
Anyway, be REAL CARFULL building the wings. If you pin them down like the plans call for, make sure all the parts fit correctly. Do NOT pin them with tight fitting parts (straining to be free) because when you release them from the board, they will take on a warp. I straightened mine out with water and weight. But we’ll cover that if it happens to your wings.
I had small flaps on the lower wing, which didn’t seem to hurt the way it flew.
The rest of the building is pretty much straight forward. Like Nils said, be sure the wings are aligned to each other.
Jerry
I have experience with a number of bipes: two that were something like the 38 Special, but with foam wings. Also the much-disliked but still cool Flyin' Fool, also the Sterling SE-5. And the Sig Fokker.
1. Keep it as light as possible. Forget fancy finishes, for example.
2. Use your favorite technique for securing the top wing to the struts. Think dowels, for example. There are hundreds of good answers here, but more Ambroid is not one of them.
3. It's easy to make an adjustable leadout guide on a bipe IB wing strut. Take full advantage of this. It's going to be nearer the bottom wing than the top, of course. And don't put too much rearwards sweep in it, either.
4. Bolt the LG on tightly. Because your Special is not going to land like a glider.
Currell
Hi,
I currently have built, and own a Brodak 38 Special with the identical power plant. It is probably one of my favorite airplanes in my fleet. It flies wonderfully, and the FP.40 seems to be a very good match to the airplane's size/wing area.
Some suggestions would be to nix the FPs stock muffler and fly without one, or order one of Stuka's tube or tongue mufflers. I have a Stuka tube muffler attached to my FP.40, and the airplane required no tail weight to assist in turning. The stock FP.40 muffler is huge and heavy, especially if it’s a RC convert.
I put a pretty decent paint job on mine, and used monokote covering, but was not afraid to use sandpaper either as a good weight saving gesture. I just love the looks of the airplane..and you will be surprised at how well it flies, especially for being a bipe.
One tricky segment of the build was aligning the wings. I see that Nils recommends a special instrument to do this, and this may be a more prudent measure. But for me, I just did it by eye and ruler and got them aligned VERY closely. This took me about 1 hour of viewing the wings from many different angles, and not cementing in the top wing until I was about as sure as I could be about the alignment.
If you use this method, pay close attention to the WING alignment to one another and the fuse/stab...NOT the fastening, or interfacing tabs/cabane strut. I am not saying to disregard them either, but don't place as much emphasis on them as much as the wings relationship to one another.
The wings are not perfectly aligned on my bipe, but they are well within tolerance, and the airplane flies wonderfully. I can get a wide degree of performance and lap speed with that airplane and engine combo just my using different propellers. I fly on 65-foot lines and can vary lap speeds from 4.5 to 5.5 seconds with that engine.
Also, someone mentioned here acquiring a specific adjustable line guide, the kit comes stock with one that works very well. I have built allot of Brodak kits, and this one seems to be of the best thought out ones. The kit is fun to build and a joy to fly. Build this one thinking 'light'in mind (light covering/paint/minimal epoxy..lots of sandpaper) and you should have a blast with this ship. It also gets allot of compliments at the airfield due to its good looks.
pr