but would my idea of having an extra port midway through the intermediate housing work?

Or would it not get enough flow in to make enough of a difference?

 

any extra spcae would help soo i couldnt see why it would not hurt anything

 

wow we are catching up with the drag time threads

 

big thread now aint it?

But hey - loads of ideas coming about now

 

Ok first of all i would like to point out there were two tests the second in which they put the engine to its limits and housed in a special test chanmber, for everybody's saftey they had the engine upto 25,000 RPM.

Also, the rotor housing wasn't that heavy and also had another housing surounding it.

So the engine had the three rotors stationally, the housings spinning around within a final larger round housing.

A few problems were that the Air/Fuel has to travel down what is the ecentric shaft (therfore the most far rotor will be running more lean), and of course the Spark plugs,
I would also like to point out you never want spark plugs on a moving part Big-G as you have to supply power to this moving part and it goes downhill real fast from there.

Another major problem i can see for the DKM type rotor engine, is its throttle response, going from 40,000 to 5,000k rpm is going to case the engine to rip out of its mounts and go walkabout...

 

well - you could use a custom ECU to ensure it reduces RPM slowly, not at a rip-roaring rate (literally!!)

But imagine it - you'd never have to change gear again when racing


Or you could always use one of these:
http://www.luk-as.de/en/produkte/innovationen/cvt.html
I cant email them - it just keeps saying that it's forbidden (??) But I'd LOVE to have this transmission in my beetle-bodied trike


Just imagine it - getting a PP engine at the peak power RPM, then simply adjusting the gearbox to accelerate, whilst keeping max power at all times!!

 

i think they use the CVT in most lawn mowers, i cant remember the main reason they didnt go into large preduction of them, i think it was noise and engine stress, i dunno but i think subaru makes a CVT in one of their cars

 

Looking at the design though, there are several modifications that can be made to the general idea that can let it hold higher amounts of power.

Firstly: It utilises a chain to apply the power, and it can only use a small amount of the edge of the chain to give "grip". If it was upgraded to a moving, adjustable-length geared cog, it could withstand higher amounts of torque.

Secondly: If you want lower noise. Use a larger angle on the main dome, and use helical-type gear cuts. On the ones that require high power handling, then a straighter-cut gearing can be used.


The most awkward problem would have to be the adjustable-length gear - since it would require a hydraulic arm to be mounted to it, and it would have to have a variable pitch to change to a larger tooth-gap when sliding up and down the main dome. Tis would then require some kind of gearing that can stand being thrown through relativelysevere angles at high RPM - like putting a universal joint through something like 10 degrees constantly


But just a second, what's the difference (in the amount of teeth) between 1st and 5th gear in an RX7? If it's only around 8 teeth, then it wouldn't even need to be very large. Theoretically, it could be made to around 5"x8"x28" (WxHxL, that's just guesstimation from standard gear sizes).


Christ - I'm kinda draing out a design for this as I'm tryping this, it's not at complicated as you'd think it would be. You'd use a standard needle-bearing CV joint on the pitch changing gear, it would "hang" off of a rotating arm mounted at the top of the gearbox. The main ome would have to have a concave surface matched to the curve of the rotating gear. And the longer you have the adjustable-length shaft, the less the angle on the universal joint. The hydraulic shifter could be mounted to the casing, and be connected to the shaft via a "collar" with needle bearings on the collar.


Reverse? errr..........

give me a few more hours on that, and I'll have that as well

 

right then, here's a fairly basic pic of how it would be constructed (minus reverse gear)

It obviously isn't a scale pic, and would have several extra bits needed to be worked out before it could be made, but you get the gist of what I mean. Reverse would possibly need to be added after the main gearbox section to ensure it wouldn't make it too complicated or bulky.

The adjustable-length shaft has a nice long body to reduce flex, but this would tend to be rather heavy if cast from steel like most gearbox's are - the same applies to the main dome, since it would probably have to a solid lump if cast.


So, looks like this thing would have to mostly machined then

 

I suppose it would help if I actually atatched it!!!

 

did you draw that??? if so nice work man

 

yeah, im always doing that kinda stuff - i havn't got a scanner, so i jus do it myself!! Probably took about 1/2 hour tho :S

 

but do you see how i mean on how it would work? and if somehow that configuration on the dome worked, then the angle applied to the universal joint would be negligible, probably only around 4 degrees at most.

But I've only just realised a kinda fatal flaw - it wouldn't really work the way i want it to!! If it was connected the way i describe, it would only RAISE the gear ratio - it would need to be connected in reverse before it would REDUCE the ratio's

 

servo would make reverse that isnt a problem, this means you could go as fast as you want in reverse

 

Now THATS a bloody good idea!!

Just imagine driving through town in reverse - oh, hang on......

......I already do that in my mini

 

sweet

 

wow....i like i like. now make ti happen capten

 

give me a machine-shop, several £££££ (im in UK) and an engine to test it with


But do you see what I meant about this thread? so far we have:

# the 15a rotary
# multiple chambers in rotors
# concave housings
# internally oilled apex seals
# PP's in the intermediate housing
# sparks in the rotors
# and a gutsy CVT

not bad for people who just have an interest in the car this style engine goes into!! But hey, should be rebuilding my 12a after xmas

 

Oh yeah, does anyone have a Lhydhalm (sp?) supercharger going cheap

 

about the sparks in the rotors...it was said before but it wont work. something about you cant have the spark plugs on the moveing part of the engine. also can you tell me how the internally oilled apex seals would work. thanks

 

what is it? is it a supercharger or is it like an electric fan or something??

 

its a constant displacement supercharger - it's better than a roots type 'charger. This is the kind that manufacturors fit as standard (look at the wipple supercharges thread in this section)

But pinkfloyyd, the apex seal idea, was that you had small holes drilled into the slots where the apex seal went, and the centrifgal force of the rotor forced oil out into the apex groove, thus giving it internal oilling (no more pre-mix or OMP setups!!). And the spark idea will work - it just won't exactly be easy to make from the bits we can get, it would have to be a custom-made jobbie, and there would probavly be a few failures before it was working properly. but I don't see why it shouldn't work

 

im going go junk yarding and see if i can find some housings to practice some of these ideas on... ill let you guys know when i find one.

 

sounds good. and i get the oil thing now.....good idea.....little late for credit...but oh well.

 

The oil idea should be the easiest to try out - since all you need is a tiny hole in each epex seal groove to allow the oil to slowly seep out. and if you use the same size drill bit, it should stay balanced as wel.

But try to get hold of an intermediate housing and see if there's going to be much overlap if you put a PP in there near the top (there aint any rotarys in scrappy's over here for me to try it on!!) It'd have to be like an upside-down smile shape, but It's always worth a try