Senior Capstone TurboJet Build - Few Questions...

[ericthegreatish]

Also, it looks like most of the heat is happening between the secondary and tertiary zones based on the coloration on the combustion chamber. I still have to figure out how to upload a picture. I have yet to pull the flame tube out.

Thanks,
Eric

[racket]

Hi Eric

You have a NOZZLE CONE fitted ? ..........please explain .

Cheers
John

[ericthegreatish]

Aug 8, 2024 16:29:04 GMT -5 racket said:

Hi Eric

You have a NOZZLE CONE fitted ? ..........please explain .

Cheers
John

Sorry, I remember when I first started the discussion someone mentioned no nozzle but a straight pipe to direct the heat away from the engine. I was just mentioning that the end of the nozzle is now conical like it should be. It tapers from 2.25” down to 1.5” ID. The overall length is in the ballpark of 10”. TOT sensor is roughly 7” from the turbo and 3” from the tip of the nozzle.

Is there any way to upload pictures directly on this site or do I have to upload them to an external source. I keep getting an error.

Thanks,
Eric

[racket]

Hi Eric

Yep , I mentioned NO NOZZLE back in May

Throw the jet nozzle as far away as you can , your engine needs a straight bit of exhaust pipe at this early stage .

A 1.5 " dia nozzle nozzle will stop your engine from working, you need to run the engine with the open pipe , get some temperature data and then think about a slight reduction in size for the nozzle , 2.25 to 1.5 is huge , the nozzle is only 44% of the exducer area , a 2"nozzle might be getting closer to whats needed at ~79% , you might find that if your temps are high even with the open pipe that you can't fit any sort of nozzle .

You need to use the Reply button on the right hand side , rather than the Quick Reply on the left , you can then add pics :-)

Cheers
John

[ericthegreatish]

Aug 9, 2024 0:36:34 GMT -5 racket said:

Hi Eric

Yep , I mentioned NO NOZZLE back in May

Throw the jet nozzle as far away as you can , your engine needs a straight bit of exhaust pipe at this early stage .

A 1.5 " dia nozzle nozzle will stop your engine from working, you need to run the engine with the open pipe , get some temperature data and then think about a slight reduction in size for the nozzle , 2.25 to 1.5 is huge , the nozzle is only 44% of the exducer area , a 2"nozzle might be getting closer to whats needed at ~79% , you might find that if your temps are high even with the open pipe that you can't fit any sort of nozzle .

You need to use the Reply button on the right hand side , rather than the Quick Reply on the left , you can then add pics :-)

Cheers
John

Will do on the nozzle. I figured I would test and then trim until I get to the magic # for the final diameter.

And when I try to “add an attachment” nothing happens. If I click the picture icon it wants a link. I’ll have to upload to photobucket or something.

Thanks again for the info,
Eric

[racket]

Hi Eric

Unfortunately we can kill our engines in 30 seconds during a failed spoolup if theres too much backpressure from an undersized jet nozzle , fitting a "tight "nozzle then cutting it back is a recipe for disaster , we need to start with an open pipe and gradually restrict it until our temps rise to the design level.

Did you try " add image to post " ??

Cheers
John

[ericthegreatish]

Aug 9, 2024 15:53:03 GMT -5 racket said:

Hi Eric

Unfortunately we can kill our engines in 30 seconds during a failed spoolup if theres too much backpressure from an undersized jet nozzle , fitting a "tight "nozzle then cutting it back is a recipe for disaster , we need to start with an open pipe and gradually restrict it until our temps rise to the design level.

Did you try " add image to post " ??

Cheers
John

Alright. Won’t do that then…

Yes, none of the buttons do anything. One opens a link to a photo hosting website and it never loads.

Thanks,
Eric

[racket]

Hi Eric

OK , I just opened the ""Reply" button on the right hand side , I press the "Add image to post" button , a "drag and post page comes up ", I minimise the Reply page and simply drag an image off my screen and hit upload ,
the pic doesn't go onto the Reply but comes up once I hit Create Post , easy for even this tech dinosaur :-)

[ericthegreatish]

Aug 9, 2024 22:31:37 GMT -5 racket said:

Hi Eric

OK , I just opened the ""Reply" button on the right hand side , I press the "Add image to post" button , a "drag and post page comes up ", I minimise the Reply page and simply drag an image off my screen and hit upload ,
the pic doesn't go onto the Reply but comes up once I hit Create Post , easy for even this tech dinosaur :-)

That’s the issue, the pop up opens but it just stays blank. Might be because I’m on a MacBook…. I’ll see if I can figure it out. Being on a bunch of car forums, I know how much more information pictures can provide than words.

Thanks,
Eric

[ericthegreatish]

Here we go, changed some firewall settings and the dialog in the popup appeared, the box was blank before. Here are some pics. 1 during self sustained idle running hot, 1 of the overall controls/engine/tanks, and 1 of the combustion chamber color. 

Thanks,
Eric

[ericthegreatish]

Some pics of the run today. Got it to idle for a few mins at TIT 735°C TOT 640°C. Picture is of a 3/4 throttle pull to 15-17psi of boost pressure. Ran a little hotter than design ~788°C but it held up just fine. Going to keep making adjustments to lower the temp a little bit. It was awesome finally getting a good run out of it! Videos soon!

Thanks,Eric

[racket]

Hi Eric

Congratulations :-)

Looking forward to the video

Cheers
John