Demon RC - Competition Belt Drive Pics

[Obeast44]

are these out yet?
where can I get one?


what kind of performance difference to you get?


Or is it just less moving parts?

They will be out in March according to DemonRC. The thing with the belt drive is its considerably less moving parts, and a more efficient drivetrain setup. The stock gears rob some power. Essentially the belt drive will be lighter, more efficient and should be more durable.

 

[DemonRC]

These are very good questions and here are the answers:


are these out yet?


Nope, we are still revising parts till we get them the way we want. This is going to push the production order back another few weeks.


where can I get one?


http://www.demonrc.com at first. We will eventually sell though dealers once we get the ball rolling.


what kind of performance difference to you get?


The timing belt drive is much more effiecient, less rotating mass, and much quieter than the current 4 gear setup. We noticed alot of drag on our test MCD RR V4's when the shafts started to wobble and the gear mesh was out of wack. Slap in the belt drive and the drag disappeared.


Or is it just less moving parts?


Not only does it reduce rotating mass, it elimates the drag from the center shaft's bearings and eliminates friction losses due to bad gear mesh. The system is very easy to maintain like the current gear setup.. You just unscrew the nuts off the shafts and the pulleys come right off. The system also eliminates one of the biggests, if not the biggest, problem with the vehicle which is a wobbly 2 piece layshaft. A wobbly layshaft will damage the bearings and gears. This was the one and only reason I got rid of my V1 TT. Now that we developed this system I wish I had it back. One of the other major improvements is that we eliminate the need for setscrews on the clutchbell and layshaft. Alot of mechanical engineers will agree that you should not be using setscrews to mount any type of gear or pulley to a shaft that is under the type of load / shock / RPMS. Instead we use a double D slotted shaft which allows us to slide the pulleys on/off but locks the pulleys on the shaft when rotated.

 

[Obeast44]

This was the one and only reason I got rid of my V1 TT. Now that we developed this system I wish I had it back.

You want the bad news? Your old TT is in Canada somewhere.


On a sidenote 1 more week til the release of the BZM engine!

 

[Fudge]

Than man, do you guys have expected release date yet?


I am very interested in getting one for my self!

 

[Fudge]

On a sidenote 1 more week til the release of the BZM engine!

Sorry, guess I'm a newbie to this site, what's a BZM engine?

 

[chevy]

Pretty sure obeast44 is talking about bi zeta motors, they make a really high quality crank for two stroke motors ddm sells, theyre manufacturing a complete two stroke motor, on their website I believe they called it a "microengine"

 

[bensonly]

any more info out on the 2 speed.


how are they coming along

 

[DemonRC]

You want the bad news? Your old TT is in Canada somewhere.
On a sidenote 1 more week til the release of the BZM engine!

OMG you mean it's been a frozen popsicle for the past 3-4 months?

Sorry, guess I'm a newbie to this site, what's a BZM engine?

The hype is that it's going to be the italian Ferrari engine for 5th scales.

any more info out on the 2 speed.
how are they coming along

Key word is "multispeed". We have two versions we are testing right now that are 100% different. One is the traditional pawl and catch shifting mechanism with a twist running on two timing belts. The other is ummm.... I'd have to kill you if I told you. I'll be releasing information on that later. I'm not too concerned that anybody is going to beat us to release since there is only one belt manufacturer is the entire known universe that can produce the belt for it and the mould for the specialized belt belongs to us. Anyways we are going to get alot more time on the two systems before releasing any detailed information on them. They are not even gauranteed to be released. If we have any doubts what so over on the prototypes we will shelf the multispeed project for another time. On a good note the 2nd tranny which is the more robust design has been a solid performer. There's one issue we are working out that will take many revisions but I think we can get that worked out within the next 60 days. I'll get information up on the website when we are ready.

 

[smoedog]

Im thinking its going to be a cvt setup

 

[booggieman2u]

Im thinking its going to be a cvt setup

Cvt would be cool but may be expensive i ran cvt on snowmobil and it was awesome but to srink it down to that small of a size would not only take alot of cad time but alot of time on cnc mill but the belt demon has designed seems like it will be a awesome bullet proof setup

 

[DemonRC]

The CVT is a fun project to work on. There are alot of pros and cons with the system though. One of the biggest problems with ANY CVT is that they are not very effiecient. This is actually counterdicting our philosophy of creating the most effiecient drive possible which is our single speed timing belt system.


The toroidal and ball CVT's we worked with handle alot of torque however they are not very efficient in that they have alot of parasitic loss on the energy required to drive them. They also require a elastohydrodynamic fluid which changes properties as it is passed between contact points. It basically turns to a solid at the contact point which greatly raises the traction. The problem in this type of CVT is you now must have a totally sealed gearbox. You also need to fit in a mechanical mechanism which changes the rotational axis of the balls which is operated by a type of centerfugal clutch. The cost of doing this will most likely the put it out of our price range. The cost of the prototypes have almost put me living under a bridge.


IVT's are much more efficient at transfering torque however they do require alot of space because of all the planetary gears involved. The torque ratings are through the roof but the high speed gear ratio will not fit our application. We didn't even bother with this one other than exploring it within our drawings.


So what we are left with is the standard ole Variable Diameter Pulley (VDP) type of CVT. This is the most common CVT we see. We can get the cost down because it not a nightmare to machine and it works well. There is a fine line between belt tension vs max torque vs efficiency vs belt life that we are working on. It's a statistical nightmare. Imagine trying to find the perfect point where the belt is tight enough were it can handle the torque from a ONB 30.5 without slipping BUT not so tight that it creates so much friction that the efficiency drops to the floor. That friction also reduces the belt life. A custom belt we had specially made helps widen out that fine line.


I'm not really worried about anybody coming in and beating us to the release. Building a car around a CVT is a walk in the park. Building a CVT to fit a car is a PITA. Building a CVT to fit a car where it isn't sticking out like a sore thumb is even worse. It also helps if you have the only the only variable speed belt in the world, made from the right materials, at a length not currently available unless you machine a custom mould, sitting on your desk.


Also we've come a long way since the first single speed belt drive and the final product should be bullet proof. I actually prefer it over running the CVT because it's maintenance free. It's also a great performance boost. Having a smooth lighter weight drivetrain defintely helps your top end.

 

[bbuzzard]

Is it March yet? ;-)

 

[booggieman2u]

Yes is it ready lol cause i really really really want one even a working proto type would work lol

 

[camo]

I want one so bad that in the mean time i'm thinking about removing the two center gears and putting a pantyhose on the two outer gears

 

[camo]

If the pantyhose doesn't work there is always rescue tape.....

 

[booggieman2u]

Any news? ????????? God the suspens is kiillllling meeeeee

 

[DemonRC]

Ya I have some good news. We have yet another revision coming. I know... I know... That sucks because it pushes release date back again but it's something we have to do. We put in a TS reed with an ONB balls-to-the-wall reed ported top end for testing. I would expect one of our belts to last at least a few gallons on a non-reed engine however it looks like a reed engine is gonna break a belt about every gallon or so which is not acceptable to us. We're pusing the belt with out another 5mm to 20mm to compensate for any ridiculous engine that some knucklehead (like my partner) wants to throw in his car. We're also going to be milling out the pulleys to lighten them up and canning the outer (bling plate).


I expect to have the parts in from the machine shop in a few weeks. If all the tolerances are good we are going to place the production order.

 

[racetruck]

Well i finally got the prototype belt drive on my MT with the brownish yellow belt and i went with the 24 tooth on the clutch side and the 28 the bottom or D side here's some pics

 

[Heavy Chevy]

Sweet! When can I get one?


Any vids?

 

[racetruck]

well he has changed the design and this was the first version that took some work to get it to fit but i made it. a video will come soon if it don't rain