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Post by jetjeff on Apr 11, 2022 15:01:20 GMT -5
Andy,
Nice work, congratulations, making a homebuilt turbine is no easy feat.
Jeff
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Post by jetjeff on Dec 31, 2021 8:56:59 GMT -5
Hi Andy,
Quite an impressive employment collage spanning 12 years. Sounds like the job anybody in this forum would love to have.
There are undoubtably parts on these aircraft we at Blevins Screw Products manufactured.
I worked at VW0A from 1979 to 1992 in the I.T. department. VW owned a Beechcraft Kingair and Rockwell Sabreliner for executive flights. VW was an outstanding company to work for.
Let us know the next company you work for.
Happy New Year
Jeff
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Post by jetjeff on Nov 7, 2021 0:58:06 GMT -5
Hi,
Chrome Moly (41xx), is a suitable shaft material. A carbide tipped tool should cut either metal, a bigger radius on the insert will provide a better surface finish.
As per the above reply, something is not set up correctly on your lathe. Cutting oil needs to be applied during the process (or the insert won't last very long).
Regards
Jeff
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Post by jetjeff on Nov 5, 2021 14:26:05 GMT -5
Hi Shanaka,
Sorry to hear about your damage.
JetJoe and Jetbeetle are the only two other companies that offer just the turbine wheel and NGV, although I have not done a search lately, there may be more.
Regards
Jeff
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Post by jetjeff on Nov 2, 2021 14:21:49 GMT -5
Hi Smithy,
Yeah, I wish I had access to one of those balancers. I did have the original turbine wheel balanced, and there was zero vibrations.
I was able to bond up the .019 gap on one side of the compressor wheel, so if it doesn't run now it never will. I'll try starting it in the next few days.
Regards
Jeff
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Post by jetjeff on Oct 30, 2021 12:21:57 GMT -5
Hi Andy,
Very nice.
Regards
Jeff
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Post by jetjeff on Oct 28, 2021 14:34:55 GMT -5
Hi Smithy,
Yeah, the GRW bearings in this engine are showing signs of wear (slight rumbling when you spin the rotor), even though total time on these bearings can't be more than 50 or so minutes.
Regards
Jeff
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Post by jetjeff on Oct 26, 2021 14:25:21 GMT -5
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
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Post by jetjeff on Oct 22, 2021 14:39:59 GMT -5
Hi John,
Your build is incredible. Also how short a time you were able to build it, uugghh I'm looking forward to retirement and the time it will give me to pursue this crazy hobby.
Working 50 hrs a week, I have virtually no time (energy) to work on my engines.
Regards
Jeff
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Post by jetjeff on Oct 21, 2021 14:27:52 GMT -5
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
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Post by jetjeff on Oct 20, 2021 14:46:37 GMT -5
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
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Post by jetjeff on Oct 18, 2021 16:43:09 GMT -5
Hi Praendy,
No machines anymore,,,what happened?
Jeff
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Post by jetjeff on Oct 18, 2021 15:51:48 GMT -5
Hi Doctorklien,
You're in the ballpark. The almost .010" of difference would allow to machine the wedges shorter if needed. Or even make the wedges slightly taller.
Regards
Jeff
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Post by jetjeff on Oct 18, 2021 14:50:05 GMT -5
Hi Steve,
If it were me, I'd contact them and ask if you can return it. Tell them what you went through to get this engine to run, see what they say.
The new comp diffuser might work, then maybe not. If nobody said this already, homebuilt turbine builds can be VERY frustrating, with many, many setbacks.
These guys must be relatively new to the micro turbine manufacture.
Regards
Jeff
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Post by jetjeff on Oct 17, 2021 11:11:56 GMT -5
Hi Steve,
I wasn't able to get to the minijetengine.com website from my Mac, but was able to view it from my iPhone. Another issue I'm seeing is with their nozzle guide vane. You can see a parallel gap between the blades, like there is no overlap, there must be overlap, with only a small V (of bladeless space)near the outer shroud.
Not sure where you are located, but I could fix the wedges in your existing comp diffuser on my Bridgeport mill,,,wouldn't take me long nor be that difficult.
Regards
Jeff
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