Just another ST50 build

[jetmanjoe]

But I have seen others on youtube use an EDF (electric ducted fan) from RC aeroplane to start their turbo jet, this is the same design.

Time will tell I guess. I do get it though, does makes sense that radial fan has more pressure from the air being thrown out by centrifugal force. Cheers for the insite

[racket]

Yep , EDF units spooling up ball bearing equiped engines get an easier job of it , but our "brass"bearings have greater frictional loads requiring more energy transfer to get them spinning .

Could you supply a Link to an engine being started with an EDF so we can have a better idea of what may or may not happen as we've only seen unsuccessful spoolups with our DIY engines using axial leafblowers .

Cheers
John

[jetmanjoe]

This is the guy.... wow I just found this video of him doing away with fuel nozzles and using a plate. Interesting concept. But it requires gas to get the engine hot first so not so great. He uses the EDF towards the end of video to start his jet. I like how he can use it to help cool the engine down after shutoff. EDF put out quite alot of thrust in air pressure. I had one for an RC plane and that plane would do over 120kmph.
I think the key to using it was not have the fan completely pushed up against the turbo inlet, but to have it away and use it to Ram air in.
youtu.be/KGIVXvqjpg4?si=sVO-zQjSD84SzGm-

[jetmanjoe]

He might also have upgraded to ball bearings in his turbo.

[jetmanjoe]

Was interesting that he used an evapator fuel plate at the top though. Makes me think about evaporators for my design as thats the Ultimate fuel atomiser

[jetmanjoe]

Ahh yep hes using ceramic ball bearings in the turbo

[racket]

Yep, Tech Ingredients thinks he knows about turbine engines but doesn't , I wouldn't be taking his advice,.......he does beautiful builds though :-)

You'll notice its a rather lengthy spoolup process for an engine without backpressure , it can be done with an EDF and ball bearings , ...... thats a very expensive and powerful EDF by the way .

I've been wanting to see their two stage setup, but haven't :-(

Cheers
John

[RADFAB]

This guy is using an edf, probably not brass bush turbo though.. 

www.youtube.com/watch?v=EuGJvRSnuMo

[RADFAB]

How long is everyone circulating their oil after shutdown? Or are you going by the temp rather than time?

[racket]

temperature exiting the turbine , I like to be <300 C - 600F

[richardm]

What about just let it run a t idle a few minutes before shutdown? Just like good practice on an automotive turbo. Or on most commercial jet and turbo shaft engines.

[racket]

One of the problems with just idling for a while is that our idling temps can be a bit higher than at say a 2:1 PR where comp efficiency is at its best .

Ball bearing equipped commercial engines with less frictional loads at idle will do better .

Axial turbine equipped engines won't suffer heat soakback to the same extent as our radial turb engines where that big lump of Inco all gets hot unlike the cooled disc of the axial wheel .

And finally , an automotive turbo at idle isn't producing boost and is often barely spinning around unlike our engines which are rotating at ~40% N1 and often at more boost than the engine would ever see .

Run high quality synthetic lube and do a cooldown , your turbo will love you :-)

Cheers
John

[richardm]

Makes sens...

[RADFAB]

Jetric just saw this video you had posted of a startup, says 150 psi used in the description? Curious if that was a typo and if not how was this done?

www.youtube.com/shorts/LS1tXcJYOVM

[jetric]

I was the first in the UK to use a scuba tank air start on a pure diy turbine, In the video I was using the scuba tank with the regulator fitted and adjusted to 150psi feeding the air into the comp housing through a hole drilled at a tangent aimed at near the comp wheel exducer through the comp front cover as John explains.
I now use the scuba tank without the regulator now and can start the engines in under three seconds, obviously you have to use high pressure hoses.
Video below of my brothers kart starting of which I built the engine, this kart did hold the land speed record once of 114mph.

youtu.be/u792K-EFe1Y?si=XEjlNFGgMUbboqmk

Richard S.

Nov 23, 2023 3:19:56 GMT -5 RADFAB said:

Jetric just saw this video you had posted of a startup, says 150 psi used in the description? Curious if that was a typo and if not how was this done?

www.youtube.com/shorts/LS1tXcJYOVM