Is there a reason one can't simply take two 13b shafts and have them put together by a machine shop to make a 4 rotor shaft? I have had this done with drive shafts before with no balancing issues.

 

the words "budget" and "4 Rotor" should never go in the same sentence.
and no, that won't work.

 

 

Thanks for the quick reply
Simple and to the point...love it.

 

Agreed... I should have said Budget 4 rotor E-shaft...

 

it's a thread like this that qualifies why people should have a 1000 post minimum before being allowed to start a new thread in this forum

 

Usually when you weld shafts, you weld both ends into a sleeve. That's how I've seen it anyway. There isn't really a place where the eshaft can be thicker.
That's problem number 1. Problem number 2 is your drive shafts probably don't go near 9000 rpm so the balancing and vibration requirements are a bit different. I imagine you wanted 4 rotors inside the same engine, not scattered around it.

 

I actually found a few references to it being done successfully on the Rx7 forum. They took two shafts and modified them so they would slip together during assembly. To prevent them from pulling apart under stress a bolt is used to hold them together. Both shafts were at 180 degrees tdc so two rotors fired at the same time minimizing stress on the join. One stock two rotor computer was used to fire all four coils by simply splitting each lead to two coils. The motor lasted several years before being pulled apart. So yes...it can be done. Not only that, they had shafts set up so you could rotate them 90 degrees during assembly to achieve a 1-2-3-4 firing order. or 13/24 at the same time

http://grannys.tripod.com/4rotorcoupling.html

 

So can a 6 rotor, doesn't mean its easy and it certainly isn't cheap(when done correctly)

 

There was somebody a long time ago talking sh-t that was never verified or ever actually proven

Would somebody please put this thread out of it's noobish misery by closing it before the your-a- flame war begins ...

Or move it to the Noob can't be flamed here forum at least

 

Yes it can be done. Not it's not as easy as just slapping two 13B eccentric shafts together, you'll need a centre bearing to get it to work.
Read here for more info Rotary Parts | Precision Engeneering

As Precision engineering about it as I believe they've done this before with Bryce McEwen's quad rotor FOURRE

 

JB Weld the shafts together and let it rip

 

:roflmao: