just one more..
 

here is another angle. This is a belt drive, with one way bearing installed..

Experimental Mods
 

Hey Dave, Im redesigning an electric crutch I made a seperate motor mount which Ive made adjustable and looks like it will work great your Belt Drive system. Im doing an electric conversion right now but going through a little down time until I get the ESC and Gyro. I had a Gyro I got In a trade but It didnt work :( The ESC I had according to CC was probably fried and needed to be fixed or replaced. As soon as I pluged it to the battery, the motor would run at full speed. Well, untill then Im grounded as far as the electric conversion goes. Wish the gas models had some kind of belt drive. Id like to give the BD system a try when I get my sparky going. ;)

Experimental Mods
 

davidhnsocal
I like what I see and $50 is a better price than the $80 I have seen the other one way bearing set ups going for.
I like the idea of no more striped gears.
Have you snapped any belts yet?
How much for the belts alone, or were would we get replacements?
I plan on going electric some time, asking for a charger for fathers day. One piece at a time but I will get there.

Experimental Mods
 

Joe-
I like your approach..

The belt drive is still really young, but I have logged a few hours of air time on it.

No snapped belts yet, no slipping either.

In the kit, i am going to include a spare belt. They are a common pitch, but there is no such thing as a common length, so I have found them very hard to locate as a stock item. I am having them cut just for little old me :-).

Of course, I will do my best to keep them on hand as well. I will be asking $3.00 each for replacement belts.

Also, FYI, the belts are spec'd at 10,000 hrs life span, but it is very dependent on the installation (size of pulleys and shaft spacing). From the normal life exp. formulas, we should easily exceed 1000 hours before the belt fails from wear. I think I will fail first!!

Experimental Mods
 

Darth-
I really feal bad about that ESC. But I remember talking about it with you, I was a little worried about that thing.

Not sure what your plans are, but I am hoping to have a couple of spare ESCs in our group soon. When one comes up, I will check in with you again and see if you still need one.

Good luck on the Sparky!!

What do you call the gas version? Smelly, or Sticky? (hehehehe)

Experimental Mods
 

Hey Dave, I appreciate the help, Im not complaining, you gave me some useable stuff at an unbeatable price. I got you covered when youre ready for a new look. i wouldnt be as far as I am with my sparky if it wasnt for your contributions. Much thanks from me to you.

Crutch design
 

My new crutch design (this one is wood) If I like this design I may go aluminum. I am also looking at Titanium. All 4 servos are closer in making linkage shorter. On the plastic crutch I had the tail servo on the tail boom. It worked well but on this crutch I left room to go either way.
I wanted to have a horizontal tray for the battery and radio. Moved the back of the landing gear back just enough to miss the V-max 7 muffler.
Still thinking about an adjustable motor mount. I must get it back in the air I am having withdraws.

crutch design
 

crutch design

crutch design
 

This is not a sparky crutch design Its for a mans heli. I mean GAS.
Just kidding I WANT A SISSY HELI TOO.

crutch design
 

LAST ONE

Experimental Mods
 

So joe, fill us in on what the benefit of your new crutch holds for the LMH flyers ? I like the "its a mans heli " line :D . Ive been flying with my new crutch design and theres no way Ill go back to the stock crutch. I was just trying to redesign the crutch for a cobra body i wanted to make and i got more than what i expected. My new crutch design has made for a better flying machine. im not going to say it is rock stable but it sure is real close. Alot more stable that the stock design. When you field your new design, fill us in on the goods.

Experimental Mods
 

OK Joe (and Darth), I opened the door for that one :D

Joe, If I may, Titanium may be a lot better, I believe it is similar in weight to the alum., but it is a lot stiffer. Probably a lot harder to machine the titanium.

What about CF? It's light and stiff. It may require more structure, or two paralled vertical members.

Darth-
What do you think made the difference when you changed the crutch? Was it moving the CG closer to the rotor, etc...?

Guys,
I got a mill, nanny, nanny, nanny..... Oh, sorry...

Depending on the material, etc, I can hand machine some of these experiments. I know it can be real hard to make the cuts you want to get the weight down....

Experimental Mods
 

From my brief stint doing some machining, I am going to have to strongly recommend avoiding the titanium. It is extremely difficult to work with, an enormous hassle to weld, and ridiculously expensive in comparison to alternative choices. Not to say it doesn’t have its places and uses, but custom built one off hobby pieces probably aren’t it.

Aluminum would be great in terms of machining and welding, assuming you have access to a TIG setup (If this causes any hesitation, again forget all of your Ti flights of fancy). Only problem there is you pretty much need to do the requisite heat treating processes after everything is machined up nice and neat if you really want to get the strength/weight ratios that make Al worth using. If you are considering using raw, non heat treated stock and some attachment method other than welding, you could probably make it a lot stronger for the same weight out of something else.

It would seem to me that carbon fiber would be a far better choice than either of the above for small, limited run, hand made hobby stuff like we are talking about. It doesn’t get much easier than cutting with hand tools and gluing the pieces together. Whats that? You can sand it by hand afterwards? Maybe even trim it with a Xacto or razor saw? Wouldn’t that be nice too… I hear that carbon fiber / Kevlar laminates aren’t all that bad :)

For what it is worth,
Spiro

Experimental Mods
 

I heard a rumor in my LHS that carbon fiber creats rf noise and makes radio systems go haywire, got any ideas on how to treat this when Using carbonfiber? I want to make a front bulkhear out of CF and just replace my broken wood ! as I have access to a computerised mill. Any ideas? Thanx

Experimental Mods
 

It is my understanding that people make R/C aircraft, both fixed wing and rotor, out of carbon fiber all of the time. I have seen many carbon fiber glider setups and scale heli setups. They usually have some sort of external antenna location. Here is a very nice CF airwolf, if you have the bucks…

http://www.variousa.com/airwolfbig.html

For what it is worth

Experimental Mods
 

OK then, does any body know where I could buy some CF then? I want to run some through the computerised mill and make myself a CF front bulkhead. Would a home improvement store have it or should I mail order some?

Experimental Mods
 

Experimental Mods
 

Thanks JoeK

Experimental Mods
 

OMG! $56 for a 15" x 15" sheet of 1/8 thick CF! Am I over reacting or should it cost that much? oh, and is that Amarican or Canadian?

Experimental Mods
 

Hehe, plywood seems pretty reasonable now, eh?

Or would you rather pony up $391.32 (US, btw) for 12" x 12" of Ti 6Al-4V. You know, just incase you want that "I can't even weld or machine this titanium" look. heheh

I imagine there are cheaper suppliers out there, and larger quantities will help out quite a bit.

Spiro

Experimental Mods
 

LOL, thanks Spiro, that lightened the mood a little, I will make a trip to my LHS to get some plywood and hopefully the dimentioned drawings of the cruch pieces like they said they would make me. If I manage to get them in AutoCAD I will Post them here, unless someone else has done this already? :confused:

Experimental Mods
 

You could probably whack a crutch out of this for $30. 12.6" x 6.5" x 0.10"thick @ 2.5mm weave.

http://www.arts-hobby.com/store/abou...id=44&compid=1

These folks advertise right here in the ad boxes. Who would have thought?

For what it is worth,
Spiro

Experimental Mods
 

Thanks Spiro, now I may actually go CF for alot more than just the front bulkhead. :idea:

Experimental Mods
 

[QUOTE]Originally posted by Darthdrk
[B]So joe, fill us in on what the benefit of your new crutch holds for the LMH flyers ?

This is not my Ideal design.
I needed a new crutch and wanted to see if I would like a flat tray for radio gear. Not crazy about every thing hanging on a rubber band.
I wanted it smaller. This is shorter than the original. I did modify every piece by the way.
Moved servos in closer. This makes linkage shorter, and helps eliminate slop & weight. Ideal would be to have cyclic servos under swashplate for CCPM = CP. Tail servo on tail (this worked good on the plastic) but made tail too heavy. It was ok if I put my 1100ma-rec bat pack on front.
This is set up for a V-MAX 7. Ideal would be an adjustable removable motor mount that could be switched for V-MAX 6, 7 or Electric motor.

Experimental Mods
 

Not that I know of. I would be very grateful if you'd post AutoCAD drawings. I'm thinking of making parts like the motor tray out of G10 fiberglass, and formally integrating mounts for the Voyager E or Ergo landing gear.