RunRyder - Tail motor instead of tail belt:

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e-Align T-REX 450-500-600 > Tail motor instead of tail belt:

Ozydego
Key Veteran
Location: Westerville, Ohio

Willy brought this up in another post and I was very intrigued by it as someone has done it successfully on rcgroups site:

Using a tiny brushless motor to drive the tail rotor and get rid of the components driving the tail via the belt. This means the lower main gear, the front pulley assy, the tail belt and the rear pulley and tension pulley. It would be replaced with a tiny outrunner motor, with a 3mm shaft that is longer than stock and a 10a esc.

I talked with my LHSguy today and I think I have worked out a pretty solid modification, using Willy's suggestion from the guy on rcgroups of course, and simpler ways to get the parts:

First, I would use the eflite park 300 outrunner motor, weighing in at 24 grams with a 3mm output shaft that is replaceable.
http://www.horizonhobby.com/Product...ProdID=EFLM1150

Second I would run wires through the boom instead of the belt and connect them to the CC phoenix 10 for power.

Third I would use raptor flybar shafts, which just happen to be 3mm steel shafts to replace the output shaft on the park 300.

Now, after the setup is complete, powering the CC at a constant speed is the next issue. I am wondering and plan on trying to piggy back off of the gyro gain channel and using it to send the signal to the CC10. I am hoping by sending a 70% gain signal, it will correspond to a 70% throttle response and then the tail will not be affected by head bogging or gov mode set for the main rotor. I would use my gain rate switch to set a rate gain of 0% to arm the CC10, then when ready to spool up, switch the gain to HH and that should start the tail rotating at 70% throttle. (I hope this works, otherwise I will have to piggy off the throttle channel and will be at the mercy of the wind if I ever autorotate.

Help me think this out guys.. the guy on rcgroups wound his own motor and I don wanna do that, and he used the throttle channel for control and I don wanna do that either... Gimme some insights and your doubts, so I can make sure I see every angle before tossing some money into this....

But Honey, I can't live with just stock.....

03-21-2006 Over year old.

ShellDude
Elite Veteran
Location: East Coventry, PA

Actually, it kinda makes sense to use the throttle channel for some kind of basic mixing. I wouldn't make it a 1:1 mix necessarily, but I do think I'd want to tie the tail rotor into my throttle curve in some manner.

If channel 5 is unused you could use it with a custom mixer using the throttle as the master. Even if you gave it some crazy mixing ratio 0 is 0 and that'd give you the necessary starting point to arm an ESC.

If you've got more than 6 channels then you could just use channel 7 or w/e as the mixing slave.

I didn't check the stats on that motor but it makes sense that you have something that runs in the 7,000-10,000 RPM range.

Shell

03-21-2006 Over year old.

slider46
rrProfessor
Location: Gloversville, NY

Just go fly a blade cp or a hummingbird v3 for a week and then come back and see if you can remember why you wanted to put a motor on the tail of your trex, to make it better......
As an after thought I'll trade you a blade cp for your trex .....

Tom..... No "D" flying....

03-21-2006 Over year old.

spork
Veteran
Location: Mountain View, CA

Quote
Just go fly a blade cp or a hummingbird v3 for a week and then come back and see if you can remember why you wanted to put a motor on the tail of your trex, to make it better......

I don't know, I think this is more interesting. On the blade you control the tail with the tail motor RPM. I think Ozy is talking about keeping the tail servo so you're still controlling yaw with the tail rotor "collective" but using a wire and motor instead of a belt.

I think the hot ticket might be to program a small AVR to mix your tail-servo and throttle output. You'd want your power to generally be proportional to your tail-rotor pitch - right?

RC

03-21-2006 Over year old.

HOMEPAGE

rerazor
Elite Veteran
Location: Mich.

Eco 7

03-21-2006 Over year old.

jcrack_corn
Senior Heliman
Location: Lafayette, LA

no mixing needed, just throw it on an unused channel and set it 70-90% (although 70% = 10,000 rpm for that motor, that is assuming 100% effic, so adjust accordingly or prop tach).

no need to adjust after that as authority will be controled by tail pitch (actually, you may have to fine tune, but once you find the sweet spot it should be fine).

Kind of interesting...it wont be anything like the blade cp (because you will have constant tail speed and of course not fixed pitch) but whether it is better (control) or more reliable than stock is very debatable...go for it and document with video and let us know!

03-21-2006 Over year old.

Ozydego
Key Veteran
Location: Westerville, Ohio

I think gov mode would definitely be the ticket, as it would compensate for the pitch changes on its own. The reason I am thinking the gain channel is that I was a little dumb in the beginning getting the Optic 6 6 channels as I said I would never need 7 channels.. nooo dang it!!

I might just have to start on the throttle channel and try other things out... as far as efficiancy, it has already been done with good results, and I wanna try to get it a little easier... not having to wind a motor as in Willys case....

With a setup like this, running gov mode on the main rotor will be like running it through a jazz with a belt..

(for those that dont get it, everything but the jazz causes wag when using gov mode (from what I've heard))

BTW, 70-75% was what I estimated as well for the tail rpms where I want them...

But Honey, I can't live with just stock.....

03-21-2006 Over year old.

Hoverdown3K
Key Veteran
Location: Rochester, New York

I don't see this as improving anything, what do you hope to gain?

besides adding another BL motor and BL ESC and drawing more power from the lipo.. what is gained?

Larger choppers are belt or shaft driven for a reason.

All you have done is created a larger Hummingbird helicopter.

-= I know there is Money in RC helicopters. I put it there=-

03-21-2006 Over year old.

HOMEPAGE

rerazor
Elite Veteran
Location: Mich.

This has and is already being done. The Ikarus Eco 7 use a tail motor with a collective pitch tail. Junk!!!!!

03-21-2006 Over year old.

AnnihilaT
Key Veteran
Location: The Netherlands Force: The Dark Side

Whether or not its an improvement, it still looks fun to try and I for one am interested to see and hear how you guys get on. If i had more time i would start on this as well just for the hell of it.

Please keep us updated with pics and vids even if its a total flop or a screaming success - I still wanna see how this works out.

A day without sunshine is like, well, night.

03-21-2006 Over year old.

HOMEPAGE

spork
Veteran
Location: Mountain View, CA

Quote
Whether or not its an improvement, it still looks fun to try and I for one am interested to see and hear how you guys get on.

I couldn't agree more!

RC

edit

DOH! I just realized I made one of those annoying "me too" posts that add nothing. Sorry guys.

03-21-2006 Over year old.

HOMEPAGE

Hoverup
Elite Veteran
Location: Gulf Coast

I too am interested in this as a solution for mini/micro scale T/R locations like the Apache and Hind T-Rex fuselages that I am building from DarthDrk.

Press on Ozydego. I did notice one small item in your thread starting post. The E-Flite motor you referenced has a 3.2mm shaft and as such some 1/8" stock could be used to fabricate a longer shaft to accomodate the pitch slider and other T/R bits. I just ordered the same motor so maybe we can share progress here.

Cheers - Boyd
AMA80393
Major USAF
Retired

03-21-2006 Over year old.

Ozydego
Key Veteran
Location: Westerville, Ohio

i did see that hoverup, but the other day while I was in my LHS, with calipers, it measured 3.01mm, so I dunno.... If it is 3.2mm stock, then I will need new tail box bearings to fit the shaft, but that shouldnt be too hard to find....

Here is Willys post that has the link to the post where Reflex has done it on rcgroups: http://www.runryder.com/helicopter/p1870850/#p1870850

Hoverdown3k... It seems that with the less drag on the drive train, the guy was getting another minute of flight out of the heli.... plus, it is not a tail like on a piccolo or hummingbird... that would be silly, this is just a different way to spin the tail but still use the stock tail pitch setup.... I would use it to keep a constant speed on the tail and possibly start using my Align gov mode, because the only issue with using it before was it causing wag in the tail, which this would fix...

But Honey, I can't live with just stock.....

03-21-2006 Over year old.

Hoverdown3K
Key Veteran
Location: Rochester, New York

Having a motor sitting on the tail of a scale helicopter is not the best look.

I think a cable drive would be better, like what others have done when converting a Blue Box model (Elite Force) to an RC helicopter

just check out the scale section.

-= I know there is Money in RC helicopters. I put it there=-

03-21-2006 Over year old.

HOMEPAGE

Grant H
Key Veteran
Location: Maryland

I was going to say that this is kinda a stupid idea but after thinking about it for a couple of minutes,now think that its something kinda cool. Not something that I would want to do, but cool none the less..

Keep us informed please.

03-21-2006 Over year old.

HOMEPAGE

catfight
Key Veteran
Location: USA

I don't know..in the video it seems to bobble (some call it hobby-horsing) a lot -with all that weight at the end of the longest fulcrum. Anyone else notice that?

03-21-2006 Over year old.

HOMEPAGE

heliboy1023
Veteran
Location: Tinton Falls, NJ

No worth it. The fact is, instead of using nice friendly pitch to control the tail, your having a motor variate speed. This can easly fail, or cause poor flying characterisics as seen with blade cp's. Just keep the belt, and tail in good shape, and it will never be a problem.

You know you have to many heli's only when your wallet is empty.

03-21-2006 Over year old.

X30pilot
Senior Heliman
Location: Plano, TX -USA

After trying to get the tail on my V1 Shogun to operate with some degree of reliability,I put a small direct drive motor on the tail. The Shogun flies great this way! I can even land in the grass with no worries. Having said that, I have been flying a V1 Trex for a year now with no tail issues. So while your idea would certainly work very well. I’m not sure why you would do it that way.

X30

03-21-2006 Over year old.

jcrack_corn
Senior Heliman
Location: Lafayette, LA

heliboy1023

you are just not getting it son.

this **in theory** should fly no different from a belt drive except:
1.) possibly more weight at tail end
2.) Possibly increased flight times as generating 10,000 rpms through a direct drive vs. through 2 gears, 2 pulley's and a plastic belt is certainly MORE efficient.

This will be constant speed variable pitch....nothing like the Toy Blade

03-21-2006 Over year old.

TomRex
Elite Veteran
Location: West Palm Beach Fl.

3mm titainium hornet shaft from helihobby, What about the inertia from the motor weight at the end of the tail boom. How bout tying the motor to the rear output shaft and keep the belt drive. Keep the weight close to center mass as possible. Right Willy?

03-21-2006 Over year old.

HOMEPAGE

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e-Align T-REX 450-500-600 > Tail motor instead of tail belt:

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