3D 4 ME

I have a Multiplex Fox that I want to convert to RC. It's been done before as I have seen on youtube, but I have no idea how to choose the right components or install them without breaking the plane. Does anyone know if there's a conversion kit for this plane or where I can find instructions on how to install the electronics?

Lnewqban

Try this:

http://www.rc-airplane-world.com/mul...onversion.html

3D 4 ME

Thanks [8D]

downunderdog

http://www.rcuniverse.com/forum/fb.asp?m=8341098

I converted a fox plus a wing from a second fox into a 4 channel biplane shown in the post above.

I used:

2 HXT 500 servos mounted in aft part of fuselage (I installed them last, moving them around to position the CG where I thought it should be) for rudder and elevator control

1 HXT900 servo mounted in the fuse above the wing for aileron control

3mm depron as the control surfaces, with 3M blenderm surgical tape as the hinges - ailerons are on the lower wings only for simplicity.

6mm depron as the spreader for the outboard area of the wings (to hold the upper wing on), covered with blenderm surgical tape - I put the upper wing slightly forward of the lower wing and tried to give it slightly more angle of attack - that way if I started to stall, the further forward wing would stall and lose lift first, causing the nose to drop and hopefully recover from the stall.

I made a firewall from 3mm plywood and bolted the engine mount to it. I cut about 3mm from the tip of the nose to square it off, and glued the plywood to the foam with Gorilla glue. I had also notched the flattened off tip area to allow the bolts from the firewall to nestle into the foam cutouts and be covered with Gorilla glue, as well - to make the glue attachment more secure and less resistant to torqueing. I also ran a couple of 3mm carbon fiber rods through the firewall and into the fuselage, and secured with foam, to brace it.

The 16g brushless outrunner was from hobbycity. With an 8x6 prop, it can just about hover/accelerate vertically. (It could hover if I were a better pilot, probably)

10 Amp Turnigy Plush ESC/BEC from hobbycity

AR6100 RX

3 lengths of 1x3 mm carbon fiber stick - one in each wing as a strut, and one running fore/aft in the lower part of the fuselage to strengthen/stiffen it up

I put together some 350 mAh 2S 20C batteries from individual cells from hobbycity.com, but then I also found a 360 mAh 2S rhino that works, too.

All of the electronics (RX, ESC, battery) fit into the cockpit area that I hollowed out with a pair of pliers and an exacto knife. Cockpit canopy is held on by magnets at the back (one in plane, one in canopy) and a strip of tape at the front.

Overall weight, with battery, is about 190 grams.

The plane flies pretty well - I'm very happy with it. I had hoped for it to be an indoor flier (which is why I went biplane - for the lower wing loading), but it's too fast for my skill level indoors.

3D 4 ME

Awesome! I think I'll be sticking with a monoplane design for my conversion though. What really troubles me is that I can't decide between a parkflyer or slope glider. The Fox seems to make a good sailplane but there's no way to get up these hills near my house. I've actually been thinking of powering it with a Cox .020 engine!

Here's a rough sketch of my conversion plans:

FlooredCOBRA

I dont think you will need that throttle servo for the Cox .020 engine. If they have a throttle it will be an exhaust slider of some sort. Run time will be about 1-2 minutes I think on stock tank unless you add a external tank. I would recommend electric that way you have complete throttle control.

Try here for some cheap combos on motor esc. http://www.graysonhobby.com/catalog/...roducts_id=619

downunderdog

I guess the 1-2 minutes run time would be ok if the plan is to get it up to altitude and then try to act like a glider... It would be cool to figure out a way to put the motor at the CG (I guess a boom over or under the fuse would do that) and then have an actuation system where you drop the motor and tank with a parachute (for later recovery... you'd have to plan according to the wind where you release it so it would land near you) to lighten the glider up for the gliding portion of the flight.

FlooredCOBRA

Ah okay so you plan to use it as a glider and want to just get it up there. That would work perfectly.

I used to do the same a long time ago with a glider I had. They do make a pod for those exact engines. From the ones I seen was for the .049 size engines. But maybe they have one for the smaller .020. All they do is rubber band to the top of the wing. Brings back some fun memories of the glider and the loud Whahhh of the .049

Here is a link to some

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJ770 http://manuals.hobbico.com/gpm/gpmg0805-manual.pdf

http://www.sigmfg.com/IndexText/SIGSH660.html

Theres another one out there that is yellow and mounts with rubber bands. But I cant seem to find the link to it. You could always make one to fit your engine and plane exactly. I would just copy the shape of the others and apply it to your set up

Good luck!

littlephoenix

here is my conversion of the FOX
[youtube]http://www.youtube.com/watch?v=zQMvPr3ESfk[/youtube]

3D 4 ME

Wow! I didn't think there was so much info out there for this topic. Thank you all so much.

3D 4 ME

Thanks, I plan to use an electric motor with a folding prop. I only thought of a nitro powerplant because I think it would be cool to have a micro nitro plane in a world full of .40+ size aircraft.

downunderdog

I used the 16 gram brushless (about $9) from hobbycity at:

http://www.hobbycity.com/hobbycity/s...idProduct=6311

and a 10 amp Turnigy Plush ESC (about $13):

http://www.hobbycity.com/hobbycity/s...idProduct=4204

and it has PLENTY of power. You could probably easily get away with the 10 gram brushless and a 6 amp ESC, especially without the extra weight of the second wing.

Let us know how it goes.

tam popo

3D and guys - I converted my Fox to brushless.....problem was I used an E-Max 2805 at 125W and 2500Kv.....way toooooo powerful!!!! It was lethal, faster than any of my Strykers and vertical was no problem. It eventually buried itself (with folding prop) into the soft earth and had to be dug out!!! I only used elevon/rudder with the 5grm servo mounted into the fuse just behind the trailing edge....used a 500Mah 2S (too big). I'm getting another to make a bipe like DownDog's and will use a BlueWonder (HXT??) motor and ailerons. Great plane as a sloper as well. Byeee......

roge_nogueira

tam popo

Roge - I think you said it right.....the lipo is too big (maybe 500 2S at most), and try to use the smallest servos you can get (5grm to 3.5grm). Weight is probably you're problem. CoG is usually 1/3rd back from leading edge. Hope this helps, mi amigo!!!

roge_nogueira

Thanks for your answer, I’ll use a smallest battery and try to fly again.

downunderdog

Total weight of my biplane was just under 200 grams with everything, including battery (360 mAh 2S that weighs about 23 grams).

With a single wing, you'd probably be wise to keep it under about 130-150 grams if you can.

My CG is just a bit - maybe 1 or 2 cm - aft of the leading edge of the lower wing. But my upper wing is about 1/3 chord forward of my lower wing, with a slightly higher AoA.

Edit to add:

The link below (from one of the posts earlier in this thread) has a picture that shows where the CG is on the stock Fox before conversion. It should be similar after the conversion, or slightly further forward if you want it to be more stable.

http://www.rc-airplane-world.com/mul...onversion.html

Dub

I got the 16g Hextronic motor and a Blue Arrow 8A esc with a 2S rhino 360mA battery for mine. However when I connect up the battery, after the little startup tune, all it does is a constant beeping. Ive tried different/bigger batteries and another tx/rx combo but its all the same. Does anyone know if its likely to be a faulty motor or esc or an esc that needs programming? Any help is much appreciated, cheers

tam popo

Dub...try moing the throttle forward, wait till the sound changes then move it back. This sometimes arms the Esc. Which TX/RX are you using, DSM2 (DX6i) or the older 35/36Mhz FM???

Wheelnut

My Feedback: (81)

The multiplex Fox has to be one of the best glider planes I've ever seen for RC conversion.

cobrajocky

That's if it's done the right way ..... "keep it lite stupid"

Everyone is making the same big mistake converting the Fox to powered by sticking a heavy big outrunner on the nose, covered or not, folding prop or not.

There are micro brushless 12x30mm inrunners that weigh less than a 1/2 to a 1/3 (14g) of the smallest outrunners, and as anyone who knows motors, inrunners are more efficient than outrunners ... it's just the physics of motor design. The Fox does not need the higher torque of an outrunner, it needs an extremely light weight efficient motor and the motor should be mounting as a pusher on a pylon on top of the fuse with a slight down thrust like an Easy Star.

The other bennifit of going with an Inrunner is that they are higher Kv, which means you only need a ligher 2S LiPO to get plenty for Revs, and not a boat anchor 3S LiPO for a slower Kv Outrunner.

I'm just working on my second Fox like this and will take pics this time when I'm finished sometime after Xmas. I only use two Blue Arrow S0251 Micro Servos 3 gram micro serovs (Elev and Ailerons) and a Corona RS400 Full Range DSP Receiver (4.3g), a 10A 9g ESC and a 180mAh 2S LiPO.

Wheelnut

My Feedback: (81)

I look forward to your mod. If yours works out well enough, I may follow your mod to the T. I hope you use some cheap stuff from HC like I do.

Dub

Hey Tam, I'm using the DX6i and I've tried that, the tone doesnt change. A friend has exactly the same setup so we will see if its the motor or esc by swapping them around. Cant get too cranky if its a faulty component that only cost 10 bucks!!!

DamonR

Have you seen a twin motor Fox?

[youtube]http://www.youtube.com/watch?v=HQINYME9R8I[/youtube]

tam popo

Damon....that is one well-made Fox!!!! We need more details etc....is it b/less, size of lipo, what motor make and size etc.

In answer to one contributor on here: My Fox was one of the first on the market and the motor and 'work' was what was lying in my parts bin waiting to be used....thats why it was so 'rough'. The next one will be quite different.
I've since been downgraded to using crutches for the rest of my life (Hip joint problem) so all my flying from now is 'close-in'. No more EasyCub, SlowSticks, Strykers etc....nope, its LiteFlite-type Bugs from now on - with no regrets!!! The one I've bought is a UK verson, the Bongo Bug. Sorry to publish on the Fox thread but here it is.....