26B E-shaft - where?

[leeroy_25]

I might be missing something here but the shaft that comes out of your gearbox and fits on your clutch is a spline and thats not even a particulary long engagement area. Also your drives shafts and prop.. It may benefit from heat treatment of sorts but I would think a deep enough spline will work fine without. Main thing is having a perfect match on the splines. If there was any for of slack to create a lashing effect then yes you would demolish it eventually.

Even using a gear manufacturer (which is probably not so easy to find generally?) I would imagine this to be an expensive route as it is a specialist process.. I was just visiting XTRAC yesterday actually who make gearboxes for a lot of motorsport applications.. The process is so highly toleranced it\'s unbelievable! very impressive machine shop though.

An option may be to buy or recycle a male and female spline section which you could weld to each corresponding shaft.. adding that much heat might upset the shaft in the first place though?

Lee

[shaunwil]

I was just visiting XTRAC yesterday actually who make gearboxes for a lot of motorsport applications.. The process is so highly toleranced it\'s unbelievable! very impressive machine shop though.

Lee

Yes It is ! I am a time served machinist who served his time machining truck components for gearboxes and diffs !

Shaun

[Archbish]

Just one question - bit of an aside.  Why set both shafts at the same angle?  Why not set them up at 90 degrees, so there are four power strokes per revolution?  Wouldn\'t that reduce stress on the splines too, or by setting them up inline, would you end up with less stress?  Presumably, you\'d have less on the centre junction, but more on the gearbox end??

[Prof]

Don\'t forget the rotors only have 3 sides.  For 2 rotor engines - the rotors are offset by 60 degrees, so the tip of one rotor would be in line with the centre face of the other one.   I am guessing for 3 rotor engines you could have all 3 faces in line or face / apex / face.
 
So by extension for a 4 rotor it woul be face / apex / face / apex - so the 2 shafts would have to be setup as shown in the piccy

[shaunwil]

There is a thread on Rx7club that states all the correct angles for up to 4 rotor engines.

Its an interesting question on how to balance a 3 and 4 rotor engine. Doesn\'t a lot of it depend on the counterbalance weight too ?

Shaun

[Archbish]

I get what you\'re saying, but if each engine is counterbalanced, why wouldn\'t you have the engines offset by 90 degrees, as presumably that would give you a powerstroke every 90 degrees?  It just looks like that you would end up with rotors 1 & 3 firing at the same time, and 2 & 4 firing at the same time...  Why wouldn\'t you want it firing 1,3,2,4 at 90 degree sequence?

[rx7boy]

I get what you\'re saying, but if each engine is counterbalanced, why wouldn\'t you have the engines offset by 90 degrees, as presumably that would give you a powerstroke every 90 degrees?  It just looks like that you would end up with rotors 1 & 3 firing at the same time, and 2 & 4 firing at the same time...  Why wouldn\'t you want it firing 1,3,2,4 at 90 degree sequence?

I like the thinking on this !! :god

[shaunwil]

But it wouldn\'t be every 90deg because the crank turns 3 times for every 1 turn of the rotor !

Would have thought the worry is is they are minutely out of sync then one would go off before the other and completely mess up one chamber ! Unless this can be fixed in ignition timing !

Shaun

[Prof]

But it wouldn\'t be every 90deg because the crank turns 3 times for every 1 turn of the rotor !
 
Would have thought the worry is is they are minutely out of sync then one would go off before the other and completely mess up one chamber ! Unless this can be fixed in ignition timing !
 
Shaun

Pair up the ignition\'s

[Archbish]

animation
ACTUAL TWIN 13B IN AN fd

^^^in the animation , it\'s showing it firing 1,3,2,4 at 90 degree difference between the rotor angles.so for that, you would have to have the eccentric shaft at 90 degrees, right?  And the FD does not sound like two simultaneous rotors firing...

((I WILL BE RIGHT!  I WILL, I WILL, I WILL!!!!))

[Archbish]

[Archbish]

having said all of the above, this is a real life example of 2 13bs plumbed together.  The reason he\'s given is for the balancing, and the counterweight removal.  

So if you can get a decent counterweight balancing done (ala Scoot 4 rotor, You Tube footage dude), then that is how to do it.  If you can\'t (ala got a garage and 2 engines), then I guess in parallel seems reasonable.

[shaunwil]

Cool, always good to learn something new

Shaun

[Bob Monkhouse]

Four power strokes per revolution? Hmm, that means you would have to have square rotors, three power cycles per revolution per rotor/housing. As for the crank/e-shaft doing three revs per rotor revolution, I think not!!

[Archbish]

*tumbleweed*