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Building Tips and technical articles. => 1/2 A building. => Topic started by: Tim Wescott on December 29, 2009, 10:44:30 AM
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What's a good size and weight for a plane to work with a Cox reed valve engine (Golden Bee style)? Dick Sarpoulis published a bunch of designs in Flying Models several years back, all for TD engines, which I have found to my disappointment to be too big for the reed valve engines, at least if you want to _do_ anything. (great trainer for the kids, though).
I'm looking for something that'll do at least the round maneuvers -- loops, wingovers, inverted, 8's, etc. I vaguely recall having a plane from Sig many moons ago that would do this, but I can't remember if it was the baby Skyray or the Dewybird with it's landing gear removed. Initially I'm thinking of an all-sheet plane, although I'd like to try a built-up wing stunter as well. I'm sure one could go bigger with a built-up wing and still have a realistic chance of keeping the weight down.
Comments on tail moments and volumes are welcome, too, although I suspect that I just want to crib off of existing stunt planes for this.
I do _not_ want to go buy any new engines -- I have about a dozen Cox reed valve engines as a consequence of a comment I made when I was in my teens, to a cousin with an unexpected ability and a large and generous circle of friends. Most of them have about as much wear as you'd expect from the usual one flight on the sleazy Cox ARFs. Passing them by in favor of some new thing would be some kind of sin, I'm sure.
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I dont know much about what is available, but i would build a baby ringmaster. Build it light and dont paint it, just clear and a little trim so you can see it. #^
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I have an unfortunate personality disorder (I think it's called 'arrogance') that makes it hard for me to build someone else's design unless it's really, really, good.
Kits are even worse -- if I make a mistake cutting a piece of wood it's just an unfortunate incident. If someone _else_ has the gall to _sell_ me a kit with a mis-cut piece of wood then they're a no good, dirty rotten so-and-so.
Besides, I'm cheap, and you can build several planes from one bag-o-balsa.
I was kind of thinking of scrawling some lines on butcher paper and building to those, once I had an idea of size.
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Tim, my Deweybird(flatwing) does great with a Black widow as well as my baby Flite Streak. Also, the Barndoor (flatwing) and the Skywriter (builtup) kits from Minnesota Modeler are great fliers with Cox engines!! And the kits are really,really good !!
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(http://i52.photobucket.com/albums/g3/Adduckted/planes/pics.jpg)
Very simple plane, save as much on weight as possible by using a "stick" fuse. 22" wingspan, 10.5" fuse, 10.5" tail. body is 1/2" balsa. Will do anything you are capable of, I once flew this exact plane with a golden bee on 30 foot lines on 30 consecutive figure 8s right after takeoff.
2 planes can be built in a day for under $10.
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John, that is a neat plane. One of my bags-o-balsa has some long sticks that are too warped for most jobs, but would probably do just fine as the stick for that.
How does the landing gear attach? And where'd you get those high-tech leadouts?
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The Musciano hollow logs need to be under 5 ounces to do aerobatics.
You could probably go as high as 6 with a genuine airfoil. All of this based on Golden Bee or Black Widow.
I have a nice TeeDee 049 with a built up wing that flys at 8 ounces.
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The Musciano hollow logs need to be under 5 ounces to do aerobatics.
You could probably go as high as 6 with a genuine airfoil. All of this based on Golden Bee or Black Widow.
I have a nice TeeDee 049 with a built up wing that flys at 8 ounces.
I have a very disappointing Cap 232 that I built by cribbing from the Sarpoulis designs; it's 7-1/2 ounces and about 150 square inches -- but his designs all used the TeeDee, and this has a Golden Bee on it.
I'm thinking of sticking my Norvel on it, but there's fit and CG problems; I'd almost have to rebuild the whole nose, and the airframe is pretty war-weary as it is. I just need to start butchering balsa, I guess...
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On the wing area 100 sq inches is a good number to go for. That is what we use on several models that we designed just for these engines. That is also the number for the planes that we designed for COX.
Larry
Black Hawk Models
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On the wing area 100 sq inches is a good number to go for. That is what we use on several models that we designed just for these engines. That is also the number for the planes that we designed for COX.
Larry
Black Hawk Models
I really ought to just buy a few of your kits, if it weren't for that dang personality disorder.
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The gear did not do well on this one, attached with a piece of glued down ribbon. What works better is to use a couple of 1/2" by 1/4" sticks for the fuse and sandwich the wing between them. Then you can glue the landing gear in there as well, just in front of the wing. FYI, the plane flies 1000 times better without the gear, just have a buddy handlaunch
As for the lead outs, I built this one several years ago to get back into the hobby and those cords were what I had laying around. I usually use wire or heavy spiderwire.
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What's up with the control system being mounted so far away from the fuselage?
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Just to add, every Brodak 1/2 a kit I've built has been a tremendous success. My fav is the f-82 Mustang kit. I must say this plane flies well right out of the box with a little tail weight and 2 Black Widows. It met its demise in a wingover when one of the engines was giving a bit of fits. The majority of 1/2 kits manufactured with built up wings fly extremely well with reedies. In addition the Lil Satan which is now being produced by Brodak is a terrific flier. Another oldie is the Goldberg Jumping Bean which is very acrobatic. These planes will fly well even with a Babe bee. My all time favorite sheet wing model would have to be the Sig Syray which just takes mounds of punishment. It flies better and better after each repair due to it being tail heavy to begin with. The nose likes to break off just prior to the wing. Getting back to the f-82, I feel this plane could even do better with 2 Sure Starts and small Perfect tanks which would eleminate the need for tail weight and give you a longer and more predictable run. Ken
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(http://i52.photobucket.com/albums/g3/Adduckted/planes/pics.jpg)
Very simple plane, save as much on weight as possible by using a "stick" fuse. 22" wingspan, 10.5" fuse, 10.5" tail. body is 1/2" balsa. Will do anything you are capable of, I once flew this exact plane with a golden bee on 30 foot lines on 30 consecutive figure 8s right after takeoff.
2 planes can be built in a day for under $10.
Well John -- look what you've done: http://www.ccwebster.net/robintim/anairplane/.
I'm not going to pop out two a day, but it's certainly coming along. (I need to go take more pictures and add to the blog).
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Yep that'll get it done. I've since taken to sandwiching the wing and elevator between 2 "sticks" and using more wing material to fill in the gap on the rest of the fuse. By doing this, you can literally pile drive a plane and it survive. Go for a hand launch, they fly much better that way. Lemme know how it flies.