Shamrock.James

Once a PP has been acomplished would it be possible to completley remove the intermediatary housings, like remove them and replace with a thin sheet of metal or something, i understand a custom E-Shaft would be nesecary but is there really anything else stoping them being removed?

Jeff20B

iTrader: (13)

Oil drains from the rotors into the intermediate housing.

Shamrock.James

yeah i understand that there is a cavity between the rotors for the oil same with the coolant, but these could just be cut from a sheet of metal.

RETed

Why would you want to do that?
Is there some logic to this or you just want a shorter e-shaft?


-Ted

yallgotboost

lighter and shorter you could make a very short 4 rotor that way

93BlackFD

racing beat aluminum housings will save you some weight, cuts it from 29lbs to 10lbs

rotarygod

iTrader: (1)

They also cut a couple thousand dollars of weight out of your wallet too.

chairchild

Just out of curiosity, which plates are the stationary gears on? Are they on the intermediate plate, or the end plates?

I'm liking this idea though - lots of oppertunity for weight loss and length reduction.

But does the oil DRAIN from the rotors into the intermediate plate, or does it just allow passage of oil from one rotor to the other? (I've yet to dismantle my engine and find out myself)

The e-shaft would have to be custom-machined from several blocks, you could have a (hollow) toothed shaft, and four off-centre cut cylinder blocks with slots to have keys inserted. This would sort out the problem of dismantleing it, but it would need a few measurements and a bit more drilling to get the right place to allow the oil to be released into the rotors.

Plus you could also change the angles of the rotors to whatever angles you liked using the keys and slots method - allowing you to do away with counterweights!!

This would also be a LOT cheaper than making the standard 20b style e-shaft

chairchild

oh yeah, and I say FOUR cylinder blocks so you can have FOUR rotors (which is kinda the whole point of this topic!)

Shamrock.James

This is more along the lines of what i was thinking, you could have a four rotor the length of a 3 or a 3 rotor the length of a 2 also i was thinking if you could significatly shorten the E-shaft it would gain a lot of strenght.

also i was thinking you may be able to put some type of bearing into the intermeditary plate as well to give the E-shaft even more support, and i think it would help the engine rev cleanly up into higher rpm's.

Only major problems that i can see are:

A. too much heat it too smaller space
B. the intermediatary plate will have to expand at a rate constant with the rest of the engine as not to destroy seals
C. it will have to be strong enough to hold the combustion pressure.

chairchild

But another thought, if you go into the realms of 4+ rotors, it'd be a good idea to add a centre bearing at a mid-point along the e-shaft. So at one point, you'd need a fairly thick plate to accomidate a bearing.

Oh yeah, and my e-shaft idea would make adding a bearing VERY easy, you'd just slide on a bearing section between the cylinders

chairchild

Right then, i've just had a look, and I've found a pic of a rotary in bits, with a view of the intermediate housing.

It appears that this idea has great potential, since there are very few actual "links" between the two housings, so a piece of plasma-nitride coated steel about 8mm thick would do the job nicely. But getting the holes machined in EXACTLY the right place could be a pain.

And then you'd have to make the e-shaft........


Anyone got a machine-shop?

chairchild

heres the pic I looked at

chairchild

Jeeez....

four posts in a row. I need to get out more!!

But here's a quick mockup of that e-shaft idea I was on about, my explanation was kinda hard to follow

Shamrock.James

I was thinking you may be able to just press the holes right through, for say a test one you might want to drill the holes then cut them to get the right kind shape but if you plan on doing quite a few i was thinking you could press them, like make a jig for either side then you put in the sheet metal, and it drop 10tonne into it just popping the holes right through...

also another note from those pics you found ... i recon you could get a lot more coolant holes going through and so get better coolant flow.

Actuually one way i recon you could do it: get a piece of the metal you decribed then just clamp it to a regualr rotor housing, flip it over get some good drill bit an then drill through sheet of metal but placing the drill bit through the rotor housing (coolant holes) so then all the holes are in the right spot, then you can widen them up from the other side (metal sheet side) using a file or bigger drill bit or whatever.

chairchild

But it's the e-shaft hole that would be a problem, how many drillbits have you seen that are THAT big

You wouldn't be able to get the clearances nessecary using a file on a hole that large, it'd be all over the place

RETed

Why don't you build the motor first and see if it'll run...
I wouldn't worry about 100 lbs. of metal unless you're talking some serious racing here.



-Ted

CarmonColvin

Sorry to hijack the thead but I noticed a mistake in the engine layout in the photo. The rotor housings are facing the wrong direction. They have the spark plugs on the same side as the intake ports.

Just an observation, not that it effects what you are suggesting.

PDF

There is a guy named Jeff Bruce here in NZ who machines up quad rotor shafts, $3500nz from memory. He also does the intermediate housing mod that involves fitting a stationary gear to each side(center housing only) and makes the thru bolts.

I saw an engine using his machined parts make its first drag strip outing a couple of months ago. It was an injected n/a 4 rotor PP in an FD doing low 11's. It sounded very similar to recordings of the Le Mans R26B.

Shamrock.James

I'm poor ATM but as soon as i see a cheap engine up for grabs i will be running all sorts of tests,

And i'ts not really the weight loss i'm looking at here its the gains in stability, if E-shaft flex can be nearly completly eliminted boosting on 3+ rotor applications will be much easier, also i was considering the idea of a second stationary gear as well, like what was said about Jeff-Bruce even maybe one with a small ofset so the rotor revolves even smoother.

also i see what you mean Carmon... hope no-one uses it as a construction example LOL.

Shamrock.James

I really like your E-shaft idea, though where you have spacers there would actually be a bearing which is a part of the intermediary plate, now the only problem I can see with the design is that if you look at the E-shaft there is a giant chunk joining it together, I’m guessing this is just for pure strength reasons... so I came up with an idea of what to do:

You will have to have a toothed shaft like you originally stated and it will have quite strong, now as for the rotor lobes you could make the rotor lobes longer as each rotor has an intermediary plate in front or behind it so you get a giant chunk of cylindrical metal, that then leave 8mm (width of the intermediary plate alone... then you lathe the rest down to create the lobe shape required, so you will have the smaller lobe cutout attached to the larger sized original full piece of cylindrical metal.

now this would slide down your new "key shaft" the larger end would go into a bearing in the intermediary plate and you would just have the lobe sticking out onto which the rotor would go.

MikeLMR

The splined shaft is a nice idea but there is the problem of clearance, you'd need some clearance to slide the lobes on but that would mean some backlash on the splines which would cause all sorts of problems as the eccentric shaft wouldn't be acting as a solid shaft.

you would need some sort of keyed interface that has a zero backlash design on each of the mating faces of the lobes and the spacers and somthing to pull them all together and put a constant tension on it to prevent it all from pulling apart.

what you would end up with is somthing that is relatively quite flexible in comparison to a solid shaft.

Shamrock.James

I understand what you are saying, precision needs to be kept throughout the whole system, we could always just make the fittings a bit tight and then just hammer the lobes down the lenght of the shaft, which in my mind is a bit crude but is always an option.

Also as for it all keeping together, a simple cross screw into the shaft would keep it all together.

IMO the rotors themselves are way too heavy and i think this is the main cause of most problems, but hey i'm a long way off from being able to redesign the rotor, and having a system that could handle them with thier current weight would mean a bulletproof system for lighter rotors.

scathcart

Well... if you really want to nitpick, then the eshaft faces the wrong way as well.

j9fd3s

iTrader: (3)

the nsu wankel spider front side housing is very thin in comparison to mazda's, so it is possible to do something like this, i question the benifits however, especially in relation to the cost involved