How about a 180 (30cc) glow motor?

[TimD]

What about combined crankshaft / flywheel weights? A100 verses K90.

 

[Ian Inverarity]

Dale,

Although the A crank is double sided it probably weighs about the same as the K-90 crank which is massive!!!

Tim,

The K-90 flywheel is average size, I used to run a flywheel that was probably larger in diameter than the K-90 flywheel on my A100 to meake it easier to start and to get the magnet in for the tacho. Also the A100 would have more rotational inertia in the crank than a K-90 os it is double sided, but not much different to the A-90.

Craig,

Not sure about the stinger diameter or pipe size effects, I only ever tried the bolly pipe on mine.

Ian.

 

[EatMyShortsRacing]

Hmmm... Am I seeing a potential pattern here...

piston weight??? after all the rest of the weight is mainly rotational???

 

[Ian Inverarity]

Craig,

I lightened my pistons..... 8)

If I make it any lighter it will probably break, which would not be pretty.

Ian.

 

[Twin_k90]

Criag,

got stuck at the panel beaters with this

i was spuewin, took longer to get the spray bog on there than expected and it was on the other side of town from hornsby!

Ian,

we need to weigh everything in the motors, at the moment it looks to me as the bore being 2mm bigger is causing the problem, bit bore motors dont want to rev, look at F1 cars, pissy bores, average storke and 10cyl to make 3L what is that saying?? small bore motors rev! i think fitting the A90 piston and sleave to a 100 case will be the answer,

Craig, any more parts lying around we can mess with?? i can supply a pipe and boat to do it in?

 

[Twin_k90]

may as well give you a engine bay pic as i have just soted the bore to storke problem,

How bout a 30cc one of these motors??

Problem solved!!

dale

 

[Ian Inverarity]

Dale,

A-90 P&L in A100 is tricky, but A100 crank in A-90 is not too hard I think.

Actually current F1 engines are well over 2:1 bore/stroke!

I have seen a rotary in a model boat, there is a guy in our club who has one! It is the OS engine. Sounds just like a full size rotary! 8)

Ian.

 

[EatMyShortsRacing]

this is great... 3 people from 3 states trying to build an engine in one place????

 

[Ian Inverarity]

Craig,

Are we talking about my engine or a new engine here? ;D

Ian.

 

[Twin_k90]

Dale,

A-90 P&L in A100 is tricky, but A100 crank in A-90 is not too hard I think.

Actually current F1 engines are well over 2:1 bore/stroke!

I have seen a rotary in a model boat, there is a guy in our club who has one! It is the OS engine. Sounds just like a full size rotary! 8)

Ian.

see if you can fit the 100 crank ian, that could be a go,

hmm dale goes to the F1 site to find engine info!!

the os ones are not good motors, i could make one heaps better, they dont have anywhere near the over lap required to make them run properly, they are a PP motor tho, just need to move the ports up to make more overlap, i reckon i could make one scream, a mate has one of the motors on his cabnet, might have to borrow it for a while!!

if the 13B which is 1300cc (2x654cc rotors) can make 600hp day in day out and 900hp for drag racing i cant see why we cant make a single rotor 30cc motor to make 20hp at 35000rpm

Craig,

just send me a motor and ill play

 

[Ian Inverarity]

Dale,

Just to try to fit the A100 crank into the A-90 is not a small job, I have to strip down two of these things and probably have some precision spacers for the crank and disc made! A lot of work!!! : I might try it, but I would put the motor back in the mono so I can get the tacho and GPS on it.

I thought measuring capacity of a rotary was a difficult thing, not really equivalent to piston engines. Also the horse power you are talking about comes from turbo-charging as well? In F1 they got to about 1200 hp from 1500cc 4 cylinders at about 6 bar boost....

Ian.

 

[Twin_k90]

hmmm maybe not worth swapping it over then ,

a 13b is rated by mazda at 654ccx2 which is 1308cc, the rta doubles it because Cams did when they first started racing them to parady, its all a load of garbage!!

to make 900hp out of a 13b is generally lots of porting, and big turbo with around 2.5bar of boost.,

my motor makes 550hp on 19psi (1.7bar) boost, and will make it all day everyday!!

Dale

 

[EatMyShortsRacing]

lemme do some tear downs of engines....

but I think putting the 100 crank in the 90 may not work because there may not be clearance for the rod (remember the rod will be 1mm closer to the case). going the oversquare route putting the 90 crank in the 100 I thought may be an idea... that would prove whether it is the piston weight is the issue??

 

[TimD]

Anyone know for a fact what rpm a CMB 1 cube will run at?

As for proving if the piston weight is the culprit - how about making it heavier and see if there is a loss in RPM? Rather than butcher engines to prove a point.

Tim.

 

[EatMyShortsRacing]

*gets the striped apron out*

and yo plan to attach the weight to the piston how without falling into the engine at high RPM??

EMS Racing Experience varies directly with the equipment ruined!!!

 

[TimD]

I didn't think that far ahead! Maybe a tungsten insert into the pin bosses?

 

[Ian Inverarity]

Craig,

Put away the butcher's apron!

I am not sure of the rod to case clearance problem with the A100 crank in the 90. However I am unlikely to pull my engines down for a couple of weeks to find out! If I did go ahead I would use that spare A-90 P&L too.

Tim,

Could make the pin from tungsten carbide, it would be heavy enough! But hard to make!!! :-

Nitrocrazed racing: Are we confused yet? What engine did that part come from...

 

[Marc_Paulais]

Hello,

I think you will be interested. Here is a picture of the prototype of the new CMB35. I do not have much info on it. It is a nitro/spark plug engine, developping more than 15 HP at 18000 rpm. It drains 7 litres (~2 gallons) of fuel per hour. Admission by rotary disk, pump and slide crab. Piston has one ring and crankcase is in three parts. The next version should be in one part.

The gas version is under development and will be commercially available if price is "reasonnable".

Sorry for the poor picture quality. It's taken from a french boat magazine with not much light (it's snowing here). Infos were from this magazine too. I'll try to scan the picture to make it look better.

Now let's see whether this attachment works...

Marc

 

[Marc_Paulais]

Well, doesn't seem to work. Sorry. I can e-mail the picture to those interested.

Marc

 

[Marc_Paulais]

I don't know why, but it worked.