smaller better?
 

wouldnt a smaller rotor be a better design, fire is basically gonna burn at the same speed and if the are was smaller it would be more effient in my mind. then we could have 4, 5, or even 6 rotor engines (yes i know they already have 4 rotor engines)! i think it would be more effecient of an engine, but there would have to be a different body design or a narrower rotor. i just think if its smaller it would be much more efficient.

comments please

sure try it out

would 10A rotors suffice?

if i had the resources i would :D

10A rotors would be too tall and thin. I think 10A width with a shorter rotor face is what you're thinking of. Basically, a scaled-down 13B rotor.

Then again, the 'stroke' would also be shorter, and the E shaft would also have smaller lobes or whatever. It would obviously have less torque.

it wouldnt have less torque if their were 6 rotors :D

plus you dont have as high centrifical force since its lighter, so you could go higher on the rpms !!! :)

I think lenght really gets to be an issue with the "more rotors" concept

bah, you would just have a shorter drive shaft, and the body would sit a bit higher

How about... Cost?

I think we need to start a "pipe dreams" subforum.

Leave it to scathcart to crash a newbies dreams!

:rofl:

Pipe dream forum, that's a good idea.

can't u just lengthen the front end to fit a 4/6 rotor?

My thoughts are also the loss of torque. As far as higher RPM with the lower torque less rotational mass theory? Hell Ken Scheepers launches at up to 11k rpm's.
I would like to see more power at lower rpm's which takes us into the opposite direction. The last thing the drive train needs is higher rpm's against it.
Ken broke his spool in his 8.8 rear and even broke the G-Force tranny. I doubt that many people in this discussion has a heavier duty drivetrain than Ken. So even though you could get more rpm's would not neccesarily be a good thing.
So to make a rotary proporionally larger would be better IMHO. An extra thought with that idea is that it gives you more room to play with intake and exhaust ports and timing.
And while you are doing this mind bogglingly expensive project please make the side plates with side exhaust ports but don't siamese them like on the renesis.

As a matter of fact I would like to see a bigger version/ higher torque rotary motor in a sport pickup.... a little 4WD pickup :)
Hey if we are talking about "pipe dreams" :confused:

yes it would be better. smaller is better. no Doubt about it. if i had a shit load of money i would find a way to make a 3-4L 12 rotor. or something like that. its just like Pistons, the Indy cars have 3L v12 in Germany. They put out like 500 or so hp. And have a red line of like 16 grand.

Ah, no it would not be neccesarily better, no doubt about it ;) If your theory was right then the NHRA Top Fuel Dragsters would be running weedeater motors. Try selling that idea to them. Or the motocross circuit would have faster bikes in the 125cc class than the 500cc class if smaller was better.
If you don't mind taking all day to reach peak power then less torque is great.

It does not matter how many rotors you add to it if your torque is low. Everytime you add a rotor you equally multiply weight the entire equation. It does add to power but the horsepower to weight ratio of the motor remains constant.
There are different applications where one is traded out over the other. Lower torque is only good for top end and really high torque is great for monster trucks (but they better have a lot of mass to maintain it)
Finding the balance of engine size, torque, and hp is the trick and there is not a one size fits all.

Sometimes people need a subtle dose of reality.

I am not subtle. :)

Y'know, actually, this makes me wonder. Would a 2-liter rotary make more power with 3 13B rotors or 4 10A rotors?

I mean, aside from the fact that an engine based off of 4 10A rotors would impress the hell out of people.

how about changing the stationary gearing? its 3:1 now if you made it 2:1 you'd get more low end....

i said IDEA not MAKING i know how much the simplest of engines cost, its insane thats why they (engine designers/ auto makers) try to keep the engine around as long as possible.

It's great to think out loud. The Wankel itself was such a bizarre idea that it was discounted by far more people than it was accepted by. It's almost as though it's whole purpose on earth is to completely go against the grain of normalcy.
Even as long as it has been around they recently made a drastic change with side port exhaust. This is the only time in my life I have ever seen a change that made a dramatic increase in power and cleaner emmissions.
Somebody had an idea there that I guaranty you even outdid their expectations. I would have loved to be at Mazda's R&D when they tested that (Renesis) the first time ;)
Take what people say with a grain of salt. You may be the next Wankel for all we know ;) The harshest critics are usually the ones that sit on their ass and have never had an original idea in their life :eek:

word dude, word :patriot:

err... no.

i think narrowing the rotor too much would make the shape of the combustion chamber even worse. the wankel is already very bad in this respect. the flame just doesnt propagate well in long and narrow spaces.

I can see the perfect use for smaller rotors. It's not so you can pack more rotors under the hood. Scalliwag's right: If we're talking about changing the rotor geometry for an automotive application, we'd be better off making a "big bore" rotory with fatter torque. We can figure out how to get a 9-10K redline out of it later. ;)
The real reason for coming up with smaller displacement rotories is for BIKES!! The bike world is seriously lacking for wankel lovin'. I think Norton came closest in the early 90s with their F1. (In fact, their design would probably make a good jumping-off point...) I don't see why we couldn't have a 500cc 2-rotor with a 18-20K redline. (Aside from the ridiculous R&D costs, anyway.) Bike trannies love that.
Yay pipe dreams!

i still think a 15a based off of 3 10a rotors would be the best comination of torque and hp

or a 20c with 4 rotors, smoooth and not too big

less problems with the apex seals if you can get more power at lower rpm's also.
But if you insist on higher rpm's use needle bearings in the rotors and mains and you could make a torque monster that would spin up high and fast ;) Then everybody would be happy especially on "dyno day" :D

i like that idea, smoother than a 2 rotor with better gas mileage than the 20b?

mike

mike you should build one.

That avatar is funny. :) Who is that guy and who is he flipping off?

if no one makes one by the time i graduate, i think i could find a good buiseness oppourtunity to use my degree with

sounds like we as a group should all put our heads together and make this 15a, we just need the 10a's first and some time. oh yea and lots of money

Enh, it wouldn't be too hard... given 10A parts. Do they *make* 10A parts anymore?

You guys go ahead; I'm going to work on figuring out a 26B that ends up enough shorter than the R26B to actually fit in something.

good luck with that one :D

the last batch of 10a parts was in like 98, (someone rebuilt a 110cosmo in the usa) they are impossible to find. for rotor housings we can turn down 12a ones, but rotors are just not available used or new

Thought as much, honestly. Oh well... guess this gets to my "aluminum billet rotors riding on needle bearings" idea. ;)


Well, honestly, I don't know that it would be that hard... I mean, aside from the obvious need to make custom intermediate plates. The R26B (I saw and took pictures of Jim Downing's motor) has intermediate plates that are probably the thickness of 20B plates... maybe a little less. If you're making them from scratch with no provision for side intake ports, you really don't need them to be *that* thick. In fact, I honestly think that if you made them from scratch, even with having a stationary gear in them you could probably get the intermediate plates to around half as thick as the normal intermediate plates!

Thinner intermediate plates means... well, obviously less thickness for the motor. If I can get the intermediate plates down to 20mm... well... 20B is 3x80mm housings, 1 40mm intermediate plate and 1 80mm intermediate plate for 360mm (not including end plates) and the 26B would be 4x80mm housings plus 3x20mm for 380mm. Which is still longer, but I think it's within the realm of possibility... Scoot's 4-rotor 23A should be 400mm and they fit *that* into an FD, so...

the nsu wankel spider plates are very thin, theres no water or intake porting in them

mike

Hmm, neat. I didn't know that. Seems to support my theory though...

dude, we all knew the germans liked david hasselhof :D

maybe you should get some nsu wankel spider rotor housings, they are available new

mike

Somehow I sorta doubt the NSU housings would bolt up to Mazda bits. ;)

back to the "smaller is better" subject. If you want to make the mazda combustion chamber better, why doesn't someone make a 13b wider? so the combustion chamber is more square. this would increase the displacement and probably increase the effeciency of the combustion chamber.

didn't mazda make a 15b or something like that with wider rotors?

15A. It was wider than a 13B, but just as tall as the 10A, 12A, and 13B.

the main problem is the combustion, which is a controlled burn, the smaller the area the less distance the burn has to travel. providing more efficiency

to make 10a parts you could cut down 12a housings and cut down the rotors on the non gear side

ahhahaha quagmire.....that show rocks man....now according to quagmire.....the smaller the burn area the more efficient it is....and according to the others the shape of the burning area is not good.....so my question is what if u made thinner rotors that have a deeper and more elongated depression....might give u the best of both worlds.....right?

the rotors and seals are really close to 10a stuff

mike

Wouldn’t this work. 13B rotors but shorter. Just as wide but shorter. This would make a more square area for combustion. Then there is always the indention in the rotor weather making it bigger or smaller would be better I do not know. Also if you made them shorter then there is less mass rotating and then you could get a higher red line I think. Also since you are making them shorter you loose displacement, so just take this little dream of mine and turn it into a 3 rotor to make up for loss of displacement or something.

shorter meaning....the rotors would have a smaller height/radius?? and once again when u add that 3rd rotor for extra displacement....ur gonna have more rotating mass!

yes i mean hight. should have said that....and i forgot about the third rotor. I thought since each rotor has less mass you could get a higher red line even though the overal mass would be greater. I am just using what i know about pistons. 3L v12 small pistons= high red line, yes i know this is not alwasy ture but overall this is what i think. let me know if i am wrong. what i mean is that the 3Lv12 can rev higher then a 3L i4 because each cylider has less mass.

while were on the topic of experimental rotary engine designs heres one ive been pondering:

ok, the rotary was originally designed as a pump... great! lets put that into practice... have a 2..well ok technically 3 rotor engine. rear two rotors would be like our 13b for combustion. but....... the 3rd rotor (probably a little less wide) would be a.... yes.... pump. pump what mr. wankle?? well why not air? ive heard rotarys are relatively efficiant as pumps... so what we would have is a supercharged 13b with the supercharger (another rotor) built into the engine! take that for the next 7 mazda! an all rotary powered, supercharged 13b renesis (and it all fits into one neat epichoidal package). :biggrin: what do you think.... heath

I love the idea of a 4 rotor made up of 10A or 12A housings for 1 reason.

Strength!

The apex seals (and any other weak point) would be just as strong as in a 2 rotor, except there are twice as many.

So a 500hp 4 rotor would be much less stressed than a 500hp 2 rotor even if they could be made with equal displacement.

But the 4 rotors get so long a traditional FR chassis layout is compromised. Must go to mid engine/rear transaxle and use the narrow engine up the middle of the car as a stressed member in a "backbone" type frame!

Could you imaging driving resting your right elbow on a 4 rotor turning 10,000rpm... At least the clutch/flywheel would be well behind you :)

from what i hear it seems that a 10a or 12a is better for a 4 rotor then a 13b. is this right.