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Post by sgmason on Feb 8, 2013 0:49:15 GMT -4
We are a small group here so I am sure that most people know I am building my own trainer from scratch. Thats right I scratched my head for a bit, and came up with my own design. It is evolving as I build it, wing shape, main fuse and interior structure/supports. Right now the plane is morphing enough that I can't even guess at the finished weight yet, but I think I am finding that nice balance between weight and durability. One of the things I have to figure out soon is the electronics for it. I have been searching the world wide web for a good guide that I understand, but so far I haven't found one I grasp the 100 watts per pound rule for a trainer, but is that the wing load or the weight of the plane? and how do I know the total weight of the plane if I don't know the weight of the electronics Any way if you have some tips on electronics selection or know of a good guide/calculator that I can punch in the specs for my plane and get a motor ESC suggestion from please tell me After I get the wing sealed up tomorrow, I will try get some pictures and post them up with specs if that helps. Thanks George
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Post by sgmason on Feb 8, 2013 20:52:02 GMT -4
Well I got my wing put together and control horns installed. It comes in at 285 grams without servos, I will be figuring out the wing area later tonight. Next I get to work on the fuselage, I want to add a strip of ply to attach the landing gear to and another strip to act as a radio tray. Pictures of the wing and its construction to come later tonight
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Post by Chris Reibert on Feb 8, 2013 21:49:33 GMT -4
About 8yrs ago I had a side company called CRmodels Hence my r/c tag on the forums. I sold custom r/c foamy flying wings and planes. I had a blast but gave it up. I used fanfold house isolation. That's how I made my aerial video What's great about foaming is it can be so funky and out of shape but with the right brushless motor anything will fly I've prob built and flown over 500 planes since I was a kid I used to make the big foam planes from the toy store r/c! I used all the equipment out of the flyzone Skyfly Max
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Post by Chris Reibert on Feb 8, 2013 21:57:48 GMT -4
Omg I found my old ad lol Ahh memories! One of my many past businesses. Was always an entrepreneur ----------------------------------------------------------------------- The “Mini Dart” Flying wing by Chris Reibert Mini Dart FLYING WING Packs an awesome punch with only a 16-inch wingspan! Specifications: Airfoil: Delta Wing Design Wing Span: 16" Length: 13 ” Flying Weight: 3.oz Weight w/out gear: 1oz The Mini Dart is a quick and aerobatic airplane with a couple of real advantages. This wing was designed around the EDP-50XC motor w/3x2 prop drive from GWS. The design goal of this plane was to have a wide speed range, long flight time, and extra crash durability. Equipment and materials were selectively chosen over other options to give the best balance of cost and performance. Mostly, the small wing shape helps for peak performance and quick turns. The 16-inch span of the Mini Dart is excellent for speed and maneuverability. The delta wing design improves clean, smooth flight characteristics. Great for combat or sport flying. Expand your horizons with the Mini Dart. Kit Includes: 10 page color Instruction booklet Wing (2) Wing Fins (2) Elevons (2) Control horns (2) Push rods (2) Zip ties Motor Mount Fin Pack of E-Z servo connectors Extra piece of patching Foam GWS EDP-50XC motor w/3x2 prop Velcro Requires: Transmitter: Any Transmitter w/ elevon mixing. Some TX require elevon mixing harness Equipment: (2) GWS Micro servos and receiver or equivalent ESC: GWS Micro Speed Control or equivalent Battery: 340-450mAh 2-Cell Li-Poly Pack Motor: GWS EDP-50XC motor w/3x2 prop (Included) Only $29.99 For more pics and Info E-mail at CRmodels@juno.com
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Post by sgmason on Feb 9, 2013 0:45:42 GMT -4
So here are a couple pictures of the completed wing. and what is inside it I haven't had a chance to figure out the wing area yet, but the wing was built in three sections. The balsa/fiberglass/epoxy spar didn't work out as I had planned so I just used a piece of ply for the the spar. To save a bit of weight I only made it half the thickness of the wing and added the foam ribs for support. I made the wing it 3 pieces for two reasons, it made it easier to add the dihedral to the wing and I was going to have to make it in two pieces anyhow to hit my 50" wing span. The seams are hot glued and clear duct taped and are extremely rigid. I cut a channel for the servo wires after I got it all together and once I install the servos I will run another piece of tape over the channel. the wing is going to be held on with the traditional trainer rubber bands and that will be my access to the electronics and battery Next is to figure out if I can get the rear stab and rudder mounted to maintain the position of a real Cub, but right now it looks like I will just have to set it on top the fuselage. With any luck I will get it sorted out during the hockey game and have a fuse update tomorrow night
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Post by Chris Reibert on Feb 9, 2013 2:14:54 GMT -4
Wow that is looking Great. Much more advance than the foamies I used to fly. For my wing spars I would just add two to the bottom of each wing and leave it unsheeted. That is going to look cool!
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Post by Chris Reibert on Feb 9, 2013 2:17:43 GMT -4
Oh and for strength on the leading ledge and to save the wing in a light crash I always wrap the leading edges in clear shipping tape!
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Post by Valkman on Feb 9, 2013 8:34:25 GMT -4
That looks great George it's coming along nice.
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Post by sgmason on Feb 9, 2013 11:48:26 GMT -4
Thanks guys, but I can't take full credit for the wing, it is based off the wings that Josh Bixler (Flitetest) makes for his scratch builds. He just uses stacked foam inside the wing as a spar, but so far his scratch builds have been smaller, 24" wing span, planes. I figured that because I was doubling that I needed a bit more support. The ribs are in there because I didn't go full height with the spar and wanted support for the top of the wing. They also made it easier to get a consistent wing shape. I think I solved my rudder and stabilizer problem, but it is going to mean that I have print up a new plan to make a new fuselage to accommodation my revisions. I have a few extra pieces of foam board, and at $1.25 a sheet its not like its going to kill me if I need more Chris since you use to build foamies to sell do you think you would be able to point me in the right direction for powering this beast? I will post the specs once I get the bare air frame finished. I need to get an idea of what I will need for a motor so I can figure out where the firewall/motor mount will go. OK off to make my revisions and cut some more foam now that I have dug out from the big snow dump yesterday ;D
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Post by Dr. Evil on Feb 9, 2013 13:22:31 GMT -4
Looking good George. The only thing I can suggest for a power setup is maybe follow whats already out there. Example: my T28 runs on a 3s and the wingspan is around 1118mm whereas my Corsiar runs on a 4s and has a 1430mm wingspan. The T28 uses a 960Kv outrunner brushless motor and a 30A ESC and the Corsair uses a 500Kv outrunner brushless motor and a 65A ESC so maybe you can follow these basic guidelines and get a good idea to what you might need for your build.
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Post by sgmason on Feb 9, 2013 18:35:11 GMT -4
The new fuselage design and tail feathers worked out as planned, only problem is I am out of hot glue sticks I am going to have to reinforce the bottom of the rudder so it transfers all of the input and gives me some place to mount my tail wheel. Next up is the piece of ply to reinforce the landing gear area, and a firewall. On that subject, Dr I was thinking of using the same motor size as the P-47. It comes in at just over 2.6 pounds with retracts and flaps on a 42" wing span. My Cub should be right around the same weight with more wing area. Only thing I would change is the amps on the ESC and go with a 40-50 amp ESC instead of the 30 amp unit the P-47 has. I will be able to get a better judgement of the weight once I get the fuselage done. I just figured out my wing area, CG and did a rough wing load calculation Wing Area: 444sq in CG: 2.11" from leading edge Wing load: 11.35 oz/sq ft Wing Cube Loading: 6.5 I am on the high side of the second set, but I may be able to trim a bit more fat off the bird before I am done.
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Post by Chris Reibert on Feb 9, 2013 20:39:10 GMT -4
+1 on what Evil said. I used to savage the gear out of other planes and build my own. The full size parkzone planes everyone are flying would be just fine. That's what I used to use Those Flitetest guys make some cool stuff! A flying cinder block...
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Post by sgmason on Feb 9, 2013 21:08:34 GMT -4
+1 on what Evil said. I used to savage the gear out of other planes and build my own. The full size parkzone planes everyone are flying would be just fine. That's what I used to use Those Flitetest guys make some cool stuff! A flying cinder block... I really enjoy the stuff they do, and they present well too. My P-47 isn't scrap yet and is completely flyable, well aside from a broken motor mount. The electronics will be HK equivalent parts which I will order the week after next. I do have a question about motor angle. The P-47 has the motor angled to the right, will I need to do that with the scratch build too? I found a bag of glue sticks so about all I have left to do is the motor mount and radio tray. I will make the battery tray after everything else is done and installed. Need to find some foam safe yellow paint too.
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Post by Chris Reibert on Feb 9, 2013 22:01:41 GMT -4
Yes a slight angle down is what I used to do. With a foamy I really don't know if it will make a difference. If you have a higher torque motor with a counter clockwise rotation you will need at least 1.5 degrees right angle on the motor to insure stable take off.
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Post by sgmason on Feb 13, 2013 18:36:11 GMT -4
Well I have gotten to a point that I can't do any more till I get my electronics. Once I have them I can build my battery tray, radio tray and motor mount, then close up the back half of the plane and make my cowl. Right now I mocked up some landing gear so I could see what I either need to buy or make. I like the idea of making my own, but I don't have any aluminum that is both the right gauge and length. I will try find a clean area that I can take a couple pictures later tonight. I have been doing a lot of painting in the house today, so there are drop sheets all over the place and the furniture is all pulled off the walls If I don't get pictures tonight I will get some tomorrow. Now that the Chinese New Year is over I can order the electronics on Monday and start the 14+ day wait for the parts to get here. With any luck I will be getting the motor mount for the P-47 on Saturday and that one will be ready to fly again.
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