Compressor

[Crazycorkey]

Is it possible to cnc mill your own compressor? I have been reading the forum and it seems you guys all buy them. How about the turbine?
Thanks

[epineh]

I have seen the diffuser blades milled, without CNC control.

Have you read Shreckling's book on model gas turbines ? His method uses timber construction (small good quality plywood) for the compressor wheel. Its worth a read even if you don't intend to build using his methods.

I have building a gas turbine on my list of things to do, just too many things higher on the list at the moment.

Russell.

[Crazycorkey]

I just ordered it along with Mike's Jet Book and Model Jet Engines by Kamps.

[epineh]

That should keep you busy for a couple of days...lol

Russell.

[vulcom1]

Although I think you could make the compressor on a cnc I think you may have problems with the curves on the blades. Also the balancing as out of the box they are ready to go. The turbine can also be made and you have the books for help but I purchased mine for the same reason as above and I have a certification for 125k's so it can be flown under MAAC rules in Canada. Not sure if they let them in the USA yet. Lots of regs.
John

[Crazycorkey]

if as you say the compressor can be made out of wood. do you think it would work as ABS plastic? i think i can get access to a rapid prototyping machine. or it can do wax so i might be able to lost wax cast one in aluminum.

[vulcom1]

The compressor that is made from plywood(aircraft) is also reinforced with carbon strands wrapped around the circumferance. I believe if you read up on it you are limited to 80k which is good to see one working. Just not enough thrust for most models but a great conversational piece. Plastic won't take the stress and I was going to make the front cover for my KJ's but got advised not to when I was with the GTBA. Some guy's had already tried that route.
Never thought of casting one but that would probably work if it is done right.(ie the blade curvature and profiles) Be advised there are different blade profiles on the same compressor.
John

[epineh]

I believe the Shreckling puts out about 6lbs of thrust, not much by today's model turbine engine standards but you could fly it if you had enough runway to get off the ground.

With the carbon fibre strands, I was wondering if you could use the braided fishing line instead, it has huge tensile strength for its size, (50lb breaking strain is smaller than "normal" size cotton) and would probably glue quite well using the same methods as Shreckling uses for the carbon fibre's.

Not that I am planning to make one in the near future, but it is the dream...

Russell.

[Crazycorkey]

There’s multiple blade profiles on one compressor? wow
That will be fun to try to accurately draft in the computer considering I’m trying to learn as I go. Haha