My first turbine - rebuild

[jetjeff]

Hi Guys,

I've decided to get my very first serious Kamps build running again.  It will require making a new turbine, reworking the compressor diffusor and possibly a new shaft, but it's much less work than building from scratch.

Here are a few pics of the turbine wheel after taking it into work and checking the blade angles on a comparator.  The angles were from 27 degrees to 31 degrees, not too bad from just using a sheet aluminum angle set to 30 degrees.

Trying to take homebuilding to the next level,,,LOL.

Regards

Jeff

[racket]

LOL.....now thats a fancy bit of gear , nice :-)

[jetjeff]

Hi Guys,

I'm making progress on rebuilding my first turbine. Turns out, it didn't need for me to remake as many parts as I thought. Basically just the turbine wheel, a fitting for initial starting gas, new magnesium engine mounts, reworking the diffusor blades as the JB weld bond broke (I used aluminum diffusor blades this time) and reworked oil line. Still faced with the dilemma of balancing the turbine wheel,,,ugh.

On a side note, I'll soon be offering N.G.V. short kits+ turbine wheel blanks for builders who are thinking of making a large (talking R/C, not the behemoths Anders and Racket make) turbines, for sale in the Trade Post section. Stay tuned.  I'll also have smaller Schreckling turbine disc, a smaller Kamps type wheel and shaft tunnel.

Regards

Jeff Pittel

[jetjeff]

Hi Guys,

Well, she's back together and ready for it's first run in 10 years.  Turbine blade tip clearance is .011"

More progress was made on the N.G.V. kits.  The inner ring was marked with Dykem layout fluid and the blade slots were scribed.

Regards

Jeff

[racket]

Hi Jeff

Lookin' sweet :-)

Time to put some colour into that wheel

Cheers
John

[jetjeff]

Hi Guys,

Tried a test run today on my rebuilt turbine just using starting gas from a small container. It seemed promising with combustion audible, and a increase in RPM. Such a small bottle of camping fuel isn't going to get it to self sustain, not YouTube worthy of a video, yet.

N.G.V. kits are also coming along, profiling the turbine wheels now

Regards

Jeff

[jetjeff]

I started tinkering again with my first build. I'm thinking it's not self sustaining due to the compressor gap being too large at the rear of the compressor. Instead of machine a new front cover, I just bogged up the area with Bondo and recontoured it. It's kind of hard to determine the radius of forward slanting bladed compressors. The compressor is not centered very well, not sure how that happened as everything was turned on a lathe. I enlarged the three front cover holes to try to center the compressor.

Regards Jeff

[jetjeff]

Hey Guys,

I'm trying to start my first turbine, after the rebuild and I'm not having any luck. Combustion only takes place after the turbine and no matter what I try the flame doesn't backfire into the combustion chamber. At first I though the compressed air from an air compressor was too much, so I switch to a shop vac, same results. No matter how I play the RPM and propane volume, I can't get it to backfire.

Regards

Jeff

[racket]

Hi Jeff

Is there any chance that the fuel and air aren't combining quickly enough ??

Cheers
John

[ripp]

Hi Jeff

how do you light the propane?

I use this lighter so I protect my fingers and the flame will not blow out so quickly








Ralph

[ripp]

I could well imagine that the overlapping of the NGV wings prevents the flames from retreating

left NGV from kj66, right from Kamps






regards Ralph

[jetjeff]

Hi Ralph,

I just use a butane cigaret lighter, the ones with the long reach for lighting BBQ grills and campfires.

Hi John,

Thats a possibility about the fuel and air, the primary combustion chamber holes may be too far back.  What keeps the flame locked to the front of the combustion chamber?

Regards

Jeff

[racket]

Hi Jeff

Good mixing and recirculation required , but if using propane it burns so readily and quickly you shouldn't have problems unless you're feeding way too much into the engine and theres not enough oxygen available untill late in the process

Cheers
John

[shanaka]

Hi Jeff,

I did something similar to this using J-B weld. Clearance has to be less than 0.1mm I guess. Mine had a slightly greater than 0.1mm gap before and it didn't even start. Right now I'm working on balancing as I felt vibrations when I started using gas. I statically balanced using one of my cheap prop balancers and it looks like it is not sufficient.

Regards,
Shanaka

Mar 3, 2021 3:35:16 GMT -5 jetjeff said:

I started tinkering again with my first build. I'm thinking it's not self sustaining due to the compressor gap being too large at the rear of the compressor. Instead of machine a new front cover, I just bogged up the area with Bondo and recontoured it. It's kind of hard to determine the radius of forward slanting bladed compressors. The compressor is not centered very well, not sure how that happened as everything was turned on a lathe. I enlarged the three front cover holes to try to center the compressor.

Regards Jeff

[jetjeff]

Hi Shanaka,

Thank you for your input. The clearance on one side of the compressor is about .004", however on the opposite side it's roughly .019", way too much.

This weekend, I'll remove the front cover and add more Bondo or JB weld.

Static balancing, isn't any where near accurate enough. I've used the prop balancer too, even machined a hub adapter to go from the 5/16" turbine hole to the 1/8" axel on the prop balancer with < .001" concentricity on the adapter. Problem is if you spin the adapter, you get different results, very frustrating.

Regards

Jeff