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  #21  
Old 24-11-2013
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so its not going to be something you can buy off the shelf?
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  #22  
Old 24-11-2013
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That depends on the success, or otherwise, of the concept.
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  #23  
Old 25-11-2013
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What are these motors normally used in; boats, planes, heli's?

I could very well imagine one of these go into a shaft-driven touringcar; just in front of a pair of saddle-packs.
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  #24  
Old 27-11-2013
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These motors are used in multi-rotor helicopters and planes. The ability to swing huge propellers without a gearbox is a big benefit. Price is lower, reliability is higher and efficiency is greater. The same benefits can all be realised in wheel driven vehicles.
On top of that, because the magnets are rotating in the open air and are mounted on a huge annular steel heat sink, they don't get as hot, so you can push these motors a lot harder than an 'inrunner' conventional car motor. So a smaller motor will give more power.

In a touring car the inline shaft concept would of course work. In my opinion, the real benefits would be realised only without the transmission shaft, with a motor in each bulkhead and no mechanical transmission at all. Then you can use electric overdrive, on-demand oversteer and all the other things that allow the car balance to be constantly fine tuned for the best performance in all situations. And you can put all your gear right where you want in the chassis - dead in the centre.
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  #25  
Old 27-11-2013
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It will need to be in the shaft - only one drive motor allowed in Touring Cars!
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  #26  
Old 27-11-2013
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Would this concept work in a v 10 I've got sitting here just fancy having a play with it
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  #27  
Old 27-11-2013
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Gerbil - yes.
SlowOne - there are far bigger obstacles than the single motor rule. For a start even one of these motors is not of BRCA legal construction in the first place.
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  #28  
Old 27-11-2013
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If,say you were running a 6.5T motor in a car,what would be the equivalent in one of these outrunner motors?
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  #29  
Old 27-11-2013
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Quote:
Originally Posted by LongRat View Post
Gerbil - yes.
SlowOne - there are far bigger obstacles than the single motor rule. For a start even one of these motors is not of BRCA legal construction in the first place.
Which is going to make it just as hard to be accepted by the 12th section for GT use!
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  #30  
Old 28-11-2013
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Quote:
Originally Posted by LongRat View Post
These motors are used in multi-rotor helicopters and planes...
In a touring car the inline shaft concept would of course work. In my opinion, the real benefits would be realised only without the transmission shaft, with a motor in each bulkhead and no mechanical transmission at all. ...
Thanks for your reply. I see your point, but with the larger diameter wheels keeping the reduction of the shaft to the diff seems like a good compromise. And keeping the diff action in is probably good too
The bulkheads are a bit narrow also, and twin moters with the assorted ESC = getting expensive

Unfortunately I don't have a shaftdriven touring car anymore to give it a try.

one more question: am I right in thinking you get a stronger effect of the drag brake adjustment without the reduction on your GT12?
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  #31  
Old 28-11-2013
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Which is going to make it just as hard to be accepted by the 12th section for GT use!
My point too. For National racing it is a totally pointless exercise. As an idea incorporating some clever concepts and a good design, I can't wait to see the full thing completed and a report on how it goes.
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  #32  
Old 28-11-2013
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Mr. Ed, the drive torque increase in this style of motor is also seen in the back EMF and drag braking effect. You don't get a stronger drag feel at the wheels, it feels much the same as a normal set up in that respect.
Believe me, choose the right motor and there would be more than enough torque to light up the tyres on a touring car without any gearing needed. But, you would certainly need the integrated diff as that's really important for the touring car. As you say, making that whole assembly narrow enough, and developing the appropriate drive electronics would be real challenges - but surely a lot of fun too.

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Which is going to make it just as hard to be accepted by the 12th section for GT use!
For God's sake Mark, can't you stop going on about the regulations and the '12th section'? This is about experimentation and trying different ideas, not winning world championships or even competing in national events. Someday, maybe this kind of thing will be popular and allowed for racing. I think we all know it isn't right now.
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  #33  
Old 28-11-2013
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Quote:
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- there are far bigger obstacles than the single motor rule. For a start even one of these motors is not of BRCA legal construction in the first place.
From the man who wants nothing said about regs, but who posts it in mardave thread .....
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  #34  
Old 30-11-2013
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Quote:
Originally Posted by LongRat View Post


For God's sake Mark, can't you stop going on about the regulations and the '12th section'?


Quote:
Originally Posted by LongRat View Post


This is about experimentation and trying different ideas, not winning world championships or even competing in national events. Someday, maybe this kind of thing will be popular and allowed for racing. I think we all know it isn't right now.
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  #35  
Old 30-11-2013
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  #36  
Old 01-12-2013
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Cool Leading the way - Maybe

Given that Brushless motors - Lipo Batteries -2.4GHz Tx have only been adopted in recent years, I must applaud the efforts and skilled endeavours of LongRat

Proof of Concept is original thinking carried into practice where it could be taken up by manufacturers that would drive prices down in volume production.

Another gain is no frictional losses via gears - the possibilities are there for IMA

GT12 is a low cost class that has a good following and innovation properly developed has a place in RC. It may take time for IMA to be accepted so keep up the good work LongRat and keep us posted
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  #37  
Old 02-12-2013
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Thanks for the encouragement.
There is a problem with the current design of the motor-diff unit, in that there is insufficient support for the rear of the rotating can. I have a couple of things to try to overcome this... I will update the thread once this is done. Here is a picture of the finished unit assembled.

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  #38  
Old 04-12-2013
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Quote:
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Here's a drawing of the assembly. I'm currently making the parts, hoping to have a running prototype by Friday. It involves making a new rotor with a row of balls built in. Because this style of motor has an external rotor, driven from the outside, it makes turning it into a 'motor diff unit' much simpler.

I must admit I still don't quiet get how this will perform as a diff.
As I see it the left outdrive will have the RPM of the motor, while the right outdrive can go faster (in a turn to the left) or slower (in a turn to the right).
Sofar all good, but driving a straight line will get difficult unless the diff is set tight enough for the right wheel to keep the same RPM.
Could be my lack of insight on how the out-runner motor functions.

I do much admire your very good finish of those mechanical parts.
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  #39  
Old 04-12-2013
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The outer can of the motor turns, which is directly connected to the ball carrier. This is the part that would normally be the spur gear in a conventional set up. So the motor drives the balls, not either of the outdrives. The outdrives are free to rotate separately from each other and from the motor can and ball carrier.
Think of it just like a conventional Mardave or pan car ball diff, but the spur gear is the end bell of an independently spinning motor.

I think I might have a solution to my current problem, some components are on order and I will update the thread when they turn up and I have made a couple more parts. Should be interesting...
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  #40  
Old 08-12-2013
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Got it, thanks for explaining that.
Looking at it now, I think the high torque comes mainly from the 14-pole design, and not as much from the out-runner principle, right?

Would it be more or-less correct ot say that you could go from a reduction of 1:R for a 3-pole motor, to a reduction 14:3R?

Do you need a different ESC for these 14-pole motors?
You mentioned the AMP ratings, but anything else? Frequency perhaps?
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