the 'rotary engine' book does talk about rotor materials, but i dont remember what it says. since they use iron side housings for cost reasons, id say that would apply to the rotors too.

one neat thing is that the lighter you make the rotating parts, the smaller the loads on everything. so right away the bearings last longer, e shaft is going to bend less at high rpms, etc etc

 

Interesting...

All I want is an all-aluminum renesis with a 10,000 RPM redline, is that too much to ask? It would be the only street legal car with a 5-digit redline.

 

Hugope,

We're not making these, Edgar Perez of E&J Autoworks is.

 

Maybe the thermal expansion coefficient of Al problems could be obviated by having ceramic or steel apex seals with a tricky way of mounting them on the rotor apexes...doesn't seem like an insur'mount'able problem.

10k rpm redline? Heck, why not shoot for 11k as a design goal?

Low compression aluminum rotors. Me want.

 

I am sure they have put thoughts into expansion rates when they design the rotors. There are probably many ways to address this problem, many we dont know of. I wonder how long they last in street applications tho. Cars with this modification will be heavily modded, NA or FI.
________
Live sex webshows

 

I'm curious as to if they have ever attempted this before and what the results were? I am pretty clueless as to some of the better names in the rotary community still so what kind of rep do these guys have?

 

Which is that book??

 

im wondering wether or not torque would drop on an aluminum based rotor engine due to lessened mass. my guess even less torque, higher horsepower due to higher rpms.

 

I would think that the same rules apply to lighter rotors as we see with lighter flywheels. Less drain on the both HP and torque, more HP and torque getting to the wheels, less resistance to RPM change.

 

my only thought in the process is basically taking the piston approach where stroke is a big deal in generating torque and less mass means less momentum (which is why higher rpms become necessary to generate the same momementums) but then again im not an engineer and im just postulating based on basic physics.

 

wow this is probibly one of hte more significant things I've seen for this motor in a ling time. nice find dude

 

Lighter rotating components do not effect torque. Only displacement does that. If the rotors were ultra dense and weighed 600 lbs each, we wouldn't have really torquey engines. They probably wouldn't even run. This is a very large misconception based on false perception. Heavier components actually hurt power and torque.

 

good to know, in the end its the same combustive power hitting whatever the material is. thanks for the clarification.

 

It takes energy to move mass. It also takes energy to slow it down. A heavier flywheel or any other component still has the same amount of energy going into it. The key is how much gets through. The heavier the mass to rotate, the less gets through to the wheels. However some of the energy is "stored" in the mass of the rotating assembly. When you try to slow it down, it resists more. This is why a decently heavy flywheel is good on the street. It may take longer to accelerate but it also takes longer to decelerate. A really light rotating assembly will rev up or down very fast. This isn't the best thing if you want to keep fairly steady rpms between shifts and it isn't as good if you are trying to drive around really slowly. I pesonally like it! "Drivability" is a very interpretive term but typically going too light affects this adversely on a street car that needs to stay smooth. Lighter will make you faster. This applies anywhere in the car whether it be just weight of the car or weight of a rotating assembly.

 

i am curious about how they will mount the gears and if they will have problems. also
olddragger

 

These will not work I am sorry to say. There is a reason we haven't seen more companies making rotors. There's much more to it than meets the eye. If they were able to dimensionally make these properly incuding seal grooves the thermal expansion rates would be the doom of it. There are other problems too unfortunately.

 

That's a good question. Racing Beat has aluminum intermediate and end housings and they've had to do some things different to make them work. The stationary gears need to be drilled out to add twice the number of bolts to hold them on. The housings have thicker castings in these areas for strength. They are also thicker in other places as well to bring back the strength of the original iron. Their tolerances are so tight on the stationary gears that you have to freeze the gears and heat up the housings to just under 400*F to get them together. They will be extremely tight. When the engine warms up these tolerances change. You need to account for everything. If they had the tolerances of the stock iron housings when at room temperature the clearances would be all off when the engine is running and the gears could move. That would be bad! These are just a few issues that make the housings difficult to use when made out of aluminum.

The rotors must have some serious issues to work out. They'd have to be thicker. The rotor gears would probably need to be done in the same way that RB is doing the gears on their housings. This is an assembly nightmare. My rear concern is with the seal grooves. These need fairly tight tolerances. How do you clearance a seal properly to account for when the engine is hot? If it's clearanced properly when hot, are the tolerances to tight when the engine is cold and is there any compression? If the tolerances were good when the engine is cold, are the too big when the engine is hot and is there added wear from the seals excessive movement in the grooves? Aluminum will wear faster with a sliding seal on it. Are the grooves ceramic coated to help both wear and expansion from heat?

Lots of concerns and issues to overcome. The issues that RB has with aluminum end and intermediate housings alone is a good case for why Mazda doesn't make them out of aluminum. The rotors are another nightmare altogether. I'd still like to see it work though.

 

I'm glad somebody finally put a stake in the vampire's heart ...

 

The doctor is in the house and just pronounced the patient dead, so can these become clocks?

 

Very attractive clocks. I'd buy one, sign me up please

Paul.

 

What about hogging out the seal grooves and gear lands large enough to inlay a steel area of OEM size and then cryotreating everything? so you would have similar to stock expansion rates in these areas?

 

The standard way that Mazda has used to cast these in the first place is not easily duplicated. It's such a precision type thing. The tolerances are top priority. This is one of the reasons that I don't even recommend that people attempt to rebuild their own engines without proper training, experience and equipment: If you don't have every seal groove properly clean you are setting yourself up for problems. Most people cannot know what properly clean means.

Nothing about the rotor is as simple as it looks.

 

I understand and I realize you and several others in this thread have infinatly more rotor knowledge than myself. I was simply thinking out loud.


I would say that is probably the biggest understatement/oversimplification ever posted on this board.

 

From a business perspective is pretty obvious why they haven't been made in the past; they just aren't enough people willing to pay for them. The only thing most of you guys will buy is something that is relatively cheap because they are made overseas by some kid who is paid fifty cents a day. Look at the percentage of turbo kits sold, how many are Greddy, and how many are made in the USA?

And you know this because you have already done it right, and you know exactly what they are going to do. Who knew all the REAL experts were hanging out the internet chatting away...

 

I was searching through some old articles and pictures of different Mazda engines. I always seem to learn something new everytime I go back and study these things. They have made aluminum rotors before. At least twice that I know of. The first was the HE10X and the second was the larger HE13X rotary engines. The HE10X utilized direct injection and redlined at 10,000 rpm. The rotors were 60% lighter than the cast iron units. The center bearing area and the area under the apex seals was not made out of aluminum. They were made of ceramic. These ceramic pieces were installed into a mold and then the aluminum cast around them into the rotor. No mention of ceramics where the side seals or oil seals were. Apparently it works. The larger HE13X engine utilized direct and conventional injection. I don't know about the redline. It made 220 hp. Aluminum has been done before as a rotor. It didn't sound cheap or easy though. Those engine were all aluminum.