160,000rpm

[skyfrog]

This little fellow of mine was put to test and up to 160,000rpm it goes w/o breaking into pieces. I saw a dollar sign on it. :0)

Quite exciting.

[Bruno Ogorelec]

Wow! I find that rpm range difficult to imagine. To me, even 16000 sounds dangerously high. Guess its all that piston engine tradition.

[mk]

Nice piece of work, Horace!

Bruno, you may find it interesting that model two stroke engines of only few cm^3 volume are running up to 35,000 rpm easily.
E.g. my tuned 3.5 cm^3 engine is optimized for about 29,000 rpm.

[skyfrog]

Is that at working temperature, Horace, or ambient?

How fast do you expect it to run in the final installation?

Hi Ben,

It was tested in working temperature, 160000rpm is its maximum in final installation.

[ed knesl]

Nice piece of work, Horace!

Bruno, you may find it interesting that model two stroke engines of only few cm^3 volume are running up to 35,000 rpm easily.
E.g. my tuned 3.5 cm^3 engine is optimized for about 29,000 rpm.

Marten, what have you done to that engine to get 29 K ?
Stock would go around 15 - 18 K.

Polished ports, tuned pipe, rear exhaust, carb tune up ?
What size prop ? Are you going to race in C/L Speed ?

Ed

[mk]

Sorry for hijacking, Horace!

Ed, it's a 3.5 cm^3 / 0.21 in^3 four-port two-stroke Force engine. Used in my 1:8 scale RC car.
The data sheet for that engine gave optimum performance for 29,500 rpm. Originally already. And a suitable range of 25,000 to 31,000 rpm.
Unfotunately the tiny channels inside are already as large as possible. There's just no room for further tuning. Even polishing would most likely make things worse, at least even with Dremel-sized tools.
Having had a closer look at the porting and port/channel areas, I must say it's a pretty neat engine as it is. So I concentrated on a proper tuned pipe. And well, it works pretty good, IMHO.

[/hijacking]

[sizzlean]

Now I don't know snot about these engines,,yet. But I just wanted to let you know that when it comes to polishing metal, especially curved, expensive surfaces the dremel is just a bad habit most of the time. If you want to polish those ports get some aluminum oxide, the higher the number the better and make yourself a cheap little sandblaster so your thing will be held in place, enclosed and funneled back into the blaster. Since your project is so small it shouldn't be much of a hassle, and since the aluminum oxide is for removing scale, rust, paint etc, it's very slow on the metal, but will work with time and polish smoother than anything except glass beads. You should be able to find these abrasives at a stucco company, or concrete company, or you can email me and I'll get you some since the project is so small it's not really worth the eighty bucks a bag. If you find a distributor try to convince the salesperson to just let some leak out the top of the bag and give him/her some lunch money. I hope this save someone from ruining their project with a damn dremel. I can get you some glass beads also, but I'm thinking it won't do anything to metal. nope nevermind the glass bead unless you want to remove oxidation.
sizzlean

[skyfrog]

My little fella has passed the overspeed test ! Up to 170,000rpm w/o fear it went !

Normally we allow 110% overspeed.

[mk]

Cool, Horace!

Would be interesting to see the turbine fail, what means getting the real maximum possible rpm number. Well, would be pretty dangerous though, too.

[skyfrog]

Cool, Horace!

Would be interesting to see the turbine fail, what means getting the real maximum possible rpm number. Well, would be pretty dangerous though, too.

We do have a burst speed on each wheel, but that doesn't worth trying, as you said too dangerous, let alone normally engine is under the control of ECU, it shouldn't go too further above the maximum speed configured in the setting.

If you are interested, a test called blade containment is more meaningful, instead of increasing the speed indefinitely. we get a blade off the wheel on purpose under a working speed, and check to see if the blade will be contained within the engine. I have seen R/R trent 900 did that, and after the test a GBP9,000,000 engine is ruined.

[mk]

Thanks for this piece of information, Horace.

I'm not that familiar with gas turbines.

[yipster]

not an expert eighter i wonder if / how much the wheel was loaded / pressurized..

[skyfrog]

Hi all,

I shipped a turbine wheel + NGV combo of this size to Brazil this week. At the first time the client gave me an address whare courier services are out of reach. Yeah, both DHL and FedEx gave me negative answer. But we managed to solve this problem by shipping to a big city where his friend lives then direct to his site by using their domestic postal services.

BTW, we manage to survive our first year doing jet engine business. Can I have a warm applause at here ? :-)

[Fricke]

Congratulations!!!

How big is Your turbinewheel?

//Fredrik

[skyfrog]

How big is Your turbinewheel?

The one I shipped this week ? a small one, of 56mm size, or 12-15lbs of thrust.