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Old Oct 07, 2010, 09:55 AM
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Indianapolis, IN
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F-82 Twin Mustang from modified P-51D Combat Plans

Hello everyone! First post here.

Just got into this in the last few months and I've scratch built an FW-190 combat plane from the combat plans here..

After a recent trip to the US Air force Museum in Dayton, OH I thought about building a combat inspired F-82 based on Ken Neal's P-51D plans. http://www.rcgroups.com/forums/showp...&postcount=250

I'm still in the design phase but here's my ideas

Wingspan Approx 36", Cord, 7.10", Length approx 25", KF-2 wing at 50% cord.
wing area would be 213 sq". I'm going to shoot for a weight of about 20 oz.

Powered by 2X 1300 Blue babyís, turning 8X6's, 10 AMP ESC's. Battery? Well Iíll get back to that later

I don't plan on flying this in combat (will be way to heavy... might make a really good battering ram though hmmm... ) so I figured I'd make couple changes.
- Full 4 channel, mounting the rudder servo on the top of the right fuselage, elevator servo will be in the left. fuselage. (facing inward)
-7.5 degree dihedral (scale) I'll be using CF spars so Iím going to have some fun making joints.
I've attached a screenshot of a drawing I made last night. Itís a rough draft as these have standard servo mount locations from original P51.

The dilemma I'm having at the moment is battery or batteries. I could use 2 X 3cell lipos in the 650 mAh range, one in each fuselage. However with such small batteries chances are one's going to always run out before the other setting up an imbalance. I could go with one big battery, but the issue comes in where to mount it. If I put it in one fuselage, Iím going to have to ballast the other one, yuck.. dead weight. And with about a .5" thick wing. not much room between the fuselages.

Flight characteristics take precedent over scale in this build. Suggestions welcome as these are my first plans
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Old Oct 07, 2010, 12:04 PM
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United States, CO, Colorado Springs
Joined Aug 2003
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IIRC, Most of the P-82s that actually saw service were night fighters that carried a large radar pod in the middle of the wign between the fuselages. Such a pod would be a great place for a battery.

http://www.456fis.org/THE%20P-51/F-82-32.jpg
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Old Oct 07, 2010, 12:58 PM
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Indianapolis, IN
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Quote:
Originally Posted by rdeis View Post
IIRC, Most of the P-82s that actually saw service were night fighters that carried a large radar pod in the middle of the wign between the fuselages. Such a pod would be a great place for a battery.

http://www.456fis.org/THE%20P-51/F-82-32.jpg
Yes I've seen the F-82's with the night fighter radome. And i'm considering it, however they look pretty ugly. However, on the upside it would give a good handle to hand launch if I wanted. So I might see. I'll do some battery research to see what would fit in a radome that doesn't it make it look like a pregnant cow.
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Old Oct 07, 2010, 03:17 PM
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Yup. Another option is to run the two powertrains completely seperate. If you run the Rx with the ESC from one and disable the BEC on the other you eliminate the risk of an imbalance causing the whole system to run off one battery while the other is sagging.

Increases risk of assymetric thrust from motor cutoff, though.

Another possibility is to tune the powertrain for 4s and run it with two separate 2s batteries bridge-wired.

Easiest answer might just be running a thicker section in the center panel. A pack that's long and skinny enough to sit in the thick part of teh wing ahead of the step should be easy to come by if you can increase the thicknes a little- maybe use 1/64th ply for the top and bottom of the battery bay instead of 3 or 6mm foam?
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Old Oct 07, 2010, 08:55 PM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
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You could do a standard installation in each fuselage with LiPo to ESC to motor but run wires through the wing connecting + to + and - to - from the LiPos.
It would just mean having 2 wires coming off each tab on the ESC side of the Deans plug, the normal ESC wire and the connecting wire.
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Old Oct 07, 2010, 10:16 PM
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Joined Dec 2008
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Hobbypartz.com has very thin 2s and 3s 1500mAh LiPos. They would probably be perfect for a single battery mid-wing mount:

http://www.hobbypartz.com/83p-1500mah-3s1p-111-20c.html

http://www.hobbypartz.com/83p-1500mah-2s1p-74-20c.html


yellow13
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Old Oct 08, 2010, 04:04 PM
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Indianapolis, IN
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Great ideas for power. Gives me a lot to think about as I'm still in the design phase. One problem I've come up with which Iím sure has been solved many times over is linkage between the dual rudders. normal control horns won't work as the geometry of them creates a differential between right and left. What I need are something like eyes that don't have offsets, like I have pictures but I've searched around (search overload) and can't find what I need yet. Something about with about a 4 by 4 mm base and maybe about 4 mm high. Anybody know a source for something like this?


I've attached a picture of something that I need, a rear view of the control system and an updated drawing with controls installed.
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Old Oct 08, 2010, 06:23 PM
Build straight - Fly twisty
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Australia, QLD, Little Mountain
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Or... Don't bother with rudders. Most RTF Lockheed Lightnings have fixer rudders and they go just fine.
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Old Oct 14, 2010, 02:10 PM
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Indianapolis, IN
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I've got most of everything figured out, this will be my next build once i finish my current project. I'm looking at power options. I figure I'll run this on a 3 Cell Lipo. I'm thinking of the following options

Option 1 1300KV blue wonder class motor with an 8X6 or 9X5. Is there a place I can get reverse pitch because i'd love that

Option 2 1500KV blue wonder with 8X4.

Option 3 Open to suggestions.
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Old Oct 14, 2010, 05:14 PM
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Attica, MI
Joined Dec 2006
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Atomo,
Your CAD model is looking good. Glad to see others taking up the torch.

As far as counter rotating props, I have not really noticed any need for such on my Mosquito.

I run one ESC into the throttle channel and the other into the rudder channel. Then use the mixing function on my Dx6i to keep them together. The real benefit is that it the motors do not quite run sync'ed, you can bump the rudder trim until they come into sync.
It also provides some yaw control. You can run single or dual batteries with this configuration.

Best wishes on your project,
Ken
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Last edited by dz1sfb; Oct 14, 2010 at 05:20 PM.
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Old Oct 14, 2010, 05:18 PM
Crash it first, Then fly it
Griffindor's Avatar
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looks nice. I think maybe making a pod would be good. It should look like a bomb that is really skinny; the new types of bomb
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