Tron Light Jet - RC Groups
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Apr 07, 2011, 01:29 AM
Rorschach's Journal
Build Log

Tron Light Jet


Trying to plan this idea out. Haven't built anything like this, so any and all help is appreciated. Thinking about 20 inch wingspan, AR6400t. I don't have experience with edfs, and rather not use them if I don't have to. Gonna be 3 channel, throttle, aileron, and elevator. I don't have a computerized radio, so using a V-tail is out.

I can already think of a few problems though:

1. Having twin props on the booms doesn't leave a whole lot of clearance. Suppose I could make it a pusher prop though.
2. I have no money, so progress is going to be at a snails pace.
3. Less importantly, how do I add all that bitchin' light piping on it?

I know there's more, but I forgot, so I'll probably be posting again when I remember.
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Apr 07, 2011, 01:42 AM
TheyreComingToTakeMeAway!
derk's Avatar
as i see it, this is going to need EVERYTHING as far forwards as you can get it to balance right. using 2 higher rpm motors and small props shouldnt be a problem. if you have a dx-7 or better, you could just get by with v-tail controls for simplicity rather than ailerons.
if you wanted to go all-out for lighting and such, i know train shops sell "light sheet" which works similar to indiglow on watches. they use it for making light up signs and such but i think you could make it work for this. or you could use fiber optics and end each wire just inside the foam about 2 mm from the edges and it should illuminate the foam. but that would take a lot of work to build the light box and route all those fibers.

cool subject though, and please post your progress
Apr 07, 2011, 05:54 PM
Rorschach's Journal
I was already thinkin the brick and battery would be going in and under (respectively) the cockpit.

And if I do get a computerized radio, if anything it'll be a DX5e, unless I can find a 6i for pretty cheap. I cant really justify a more expensive radio for my small planes that fly without a computer radio, and I just don't have the time to go anywhere but the park by my apartment to fly. It's about the size of a football field, but theres always people there, so smaller birds are pretty much I can comfortably fit. so aileron and elevator much be a bigger pain to work out, but it's pretty much all I can do right now.

At a 20" span, there's just under 6" between the booms. The PZ UM P-51 props I have are 5 1/8 of an inch across, so I wouldn't need to cut them down. Have them powered by a pair or 6mm cub motors and run it all with the e-flite 1s 500 mah battery... Seems like it would work, right?

Probably not going going to worry about the ligts just yet... maybe on V2.0 lol

Now I need to order foam and start drawing out the plane.

Still feels like I'm overlooking more than I normally would...
Last edited by PierceOConnell; Apr 07, 2011 at 06:08 PM.
Apr 07, 2011, 06:26 PM
Flash, AAAAAAAAAAAHhhhhhhhhh
flashkick's Avatar
wait cub motors in the mustang gearbox? do you mean using 2 cub motor, gearboxes, props(best idea)?
Apr 07, 2011, 06:42 PM
Rorschach's Journal
Quote:
Originally Posted by akwardflyer
wait cub motors in the mustang gearbox? do you mean using 2 cub motor, gearboxes, props(best idea)?
Yeah, cub motors, gearboxes. Was thinking of using the mustang prop since I have a few, but now that I think of it, isn't the prop shaft smaller on the cub gearbox than on the mustangs? they're only a few dollars anyway, so it's not like it's gonna be real expensive to add a pair of props to the bill
Apr 07, 2011, 06:46 PM
Rorschach's Journal
Another thing I thought of, will it cause any problems with torque roll to have two motors spinning the same direction?
Apr 07, 2011, 06:57 PM
Power Wheels Guru
UNGN's Avatar
Counter rotating Mosquito Props/Motors and Gearboxes would work better than Mustang motors and props.

On your design, draw a line 1/3 of the wing's chord length back from the LE. This is the absolute maximum Center of gravity the plane can have, or it won't fly controllably.

Basically ALL of the electronics will need to be mounted in front of this line.

The V tail design works like elevator and a rudder. If you flatten out the V, you are going to need a rudder.
Apr 07, 2011, 07:12 PM
Rorschach's Journal
Quote:
Originally Posted by UNGN
Counter rotating Mosquito Props/Motors and Gearboxes would work better than Mustang motors and props.

On your design, draw a line 1/3 of the wing's chord length back from the LE. This is the absolute maximum Center of gravity the plane can have, or it won't fly controllably.

Basically ALL of the electronics will need to be mounted in front of this line.

The V tail design works like elevator and a rudder. If you flatten out the V, you are going to need a rudder.
I didn't think about the Mosquito motors. Those are probably the better idea all around, being heavier, more powerful, and the 3 blade prop would probably give me more clearance between themselves.

I'm already planning on having the brick, battery and motors up front. the only thing behind them will be foam, glue and servo linkage.

The tail is going to stay with that wide V shape. I'm going to use the elevator servo, make an elevator surface on each side of the v, and connect it with a Y at the end of the linkage. That with the ailerons should work, right?
Apr 07, 2011, 07:59 PM
Flash, AAAAAAAAAAAHhhhhhhhhh
flashkick's Avatar
vtail would be lighter.
Apr 07, 2011, 08:55 PM
Post Digger
Baratacus's Avatar
couple things that stand out to me. 1: you wont have any yaw control unless you use 2 servos with the v-tail. 2: with a wing that flat, it's going to be as skittish as a moth. They only go straight when they fart.

Maybe a little more dihedral and use motor mixing for differential thrust yaw steering. that way you can still use a single servo for the tail. el wire is good for the piping effect, but it's heavy. Not only would there be the plastic piping, but it needs an inverter for the power supply, more weight. fiber optic lights just light the ends of the fibers, not the full strand. LED's would make hot spots, and wouldn't give you a crisp line. Maybe You can paint the edges with glow in the dark paint and just charge it with a flood light before you send it up. that Should stay lit longer than a battery pack would last on a twin engine UM.

have you thought of doing a cheaper build with something like the airhogs jetscream or A10 for guts and parts?
Last edited by Baratacus; Apr 07, 2011 at 09:00 PM.
Apr 07, 2011, 11:09 PM
Rorschach's Journal
Is yaw control all that important? I've seen many planes without any kind of yaw control.

As cool as it may be to do the lights, I doubt it's going to happen with this build.

The first picture I had posted is of a toy that came out for the movie. The model I build is going to have dihedral in it. I was thinking with the cub motors, a wing like the HZ champ would do it, but I think a slimmer one will be better if I do the Mossie motors.

I thought about the air hogs stuff, and maybe making the tail booms hollow for them. Not sure how to wire it up, if they'd provide enough thrust, etc.
Last edited by PierceOConnell; Apr 08, 2011 at 02:16 AM.
Apr 07, 2011, 11:19 PM
Registered User
jarel design's Avatar
smiling here... normally an airframe designer and no time to contribute much in that department, however...

In motion picture special effects models we've used side emitting fiber optics... don't have the source at hand, but basically, you pipe in all the fiber to a high intensity LED and the light comes out the sides of the length of fiber and not the tips as most people expect with fiber optics...

great project!

GOOD LUCK!

Best,
Richard
Apr 08, 2011, 10:27 AM
Post Digger
Baratacus's Avatar
Richard: I don't think I've ever seen side emitter fiber optic cable that's under 5 or 6mm diameter, but I don't work in the special effect industry either. If you have a source for some 1mm stuff he may be able to make that work. Do they have side emitter fiber optic cable that small?

Pierce: If you have enough dihedral, yaw isn't going to be a problem unless you roll the plane too steep. I searched out some pictures, and the model they used in the movie actually has quite a bit of dihedral, where the toy is pretty much flat as a plank. Using the v-tail for elevator only, you may have a bit of yaw slop in the plane when banking.. should be interesting to see how it handles. The airhogs jetscream and foxfire both have twin 30mm ducted fans, they have plenty of push. I would be interested to see how well they would work wired to a PZ twin motor brick with it's 3 amp output.
Apr 08, 2011, 11:37 AM
Registered User
jarel design's Avatar
Boy, I hadn't thought about size... I really don't know as the stuff we've used in the past was probably about 1/4"... Again, this will be something you'll have to search the internet for... I just wanted you to know that it does exist, just don't have a source and now, I really don't know size availability.

another idea... if you can get a hold of some regular fiber optics (you can always ask for a small sample from a dealer/manufacturer), try roughing up the sides... the scratches should catch the light and give you at least a good "glow"?

Best,
Richard

PS: regarding dihedral and "fly-ability"... remember... "smoke and mirrors" LOL! It's all done with smoke and mirrors...

just because the art director on a film or the lead designer at a toy company draws it a certain way, (unless it was specifically designed to be flown, use all the resources you can (Some GREAT designers/builders here already on this thread!) and adapt the design to your performance needs... don't get caught up in following what I call "reference" photos or models...

I built the flying police car models for the 5th Element... I KNOW they won't fly! (unless someone builds a really lightweight shell, mounts a quad copter inside, opens up the bottom and opens up all the windows or some some other inventive approach.

Still watching here (Sheesh! I still haven't even seen the movie! I'll go rent it soon just to see where your inspiration came from...)

Again, wishing yo the best on this project! (I totally admire anyone who tackles a project like this with an attitude of "This is what I want" rather than does someone think this is possible... Look at the wright brothers! lol!

Richard

Wish I could be more helpful, but my work load is overflowing at the moment. Both client prototypes and new JADE kits
Apr 08, 2011, 08:34 PM
Registered User
Petefoss's Avatar
Quote:
Originally Posted by jarel design
I built the flying police car models for the 5th Element... I KNOW they won't fly! (unless someone builds a really lightweight shell, mounts a quad copter inside, opens up the bottom and opens up all the windows or some some other inventive approach.
Years ago I flew a 7/8 scale flying car that a friend at Chrysler managed. They were blimps with a 1 mm thick thermoformed foam shell over the gasbag. They looked really cool but flew terrible compared to blimps like you see in sports events. Which fly bad by the way!

http://www.flickr.com/photos/30242495@N04/3308793207/
http://www.flickr.com/photos/bbautista/272668228/

I've flown both of the above for the Detroit Pistons.

Pete


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