HPST 2020 Jet Engine

[praendy2203]

Hi,
my name is Andy, 44 years old from Germany.
Racketmotorman John "invited" me, to join your Site.

[praendy2203]

Here you find a Link from the build thread!
Its all written in German, but there are a lot of pics.
Started in 2018 and HPST 2020 does mean, High Power Spaghetti Topf (Pot) built in 2020.

www.rc-network.de/forum/modellflug/turbinen-jets/687612-turbine-mit-135-mm-verdichter-und-turbinenrad-aus-titan

[praendy2203]

Hi,

here my Youtube Channel!
There you find some construction videos!

Cheers Andy

www.youtube.com/user/Praendy

[racket]

Hi Andy

Welcome to JATO :-)

Its a great build you've done , beautiful job , I'm really looking forward to watching your development of the engine, and if we can be of some help , please throw us some questions and we'll do our best to provide answers

Google translation produces an "interesting" read of the Build Thread ..................the pics are worth a thousand words that speak an universal language .

Thank you for joining and contributing

Cheers
John

[madpatty]

Hi Andy

Welcome to JATO :-)

You have done a great job with your engine build. That variable nozzle you designed is especially “drool” worthy.
Looking forward to watch your engine development.

Cheers
Patty

[praendy2203]

Hi John, Hi Patty

one question!
Where is the best location to take compressor pressure?
Now I use the gas pipe backwards, after shut the gas bottle. In front I have a check valve installed.
The gas pipe of curse ends in the combustion chamber. I am wondering about my low pressure on the gauge, when the engine is in idle.
Only 0,2 Bar.
When I look to the flow chart from Garret, its much more shown at this Rpm.
0,5 -0,6 at this speed!
Wheel is Garrett GTX5533 Gen.II
94 mm In and 133 mm Ex.
For me there is no difference, where to take out the pressure inside the engine!
I am right?

Thank you!

Cheers Andy

[madpatty]

Hi Andy.

I usually have my pressure P2 pickup right near the diffuser outlet from a hole drilled and tapped near where the diffuser axial straightening vanes are present.

Cheers.

[racket]

Hi Andy

I've also used the propane delivery/injection plumbing to measure P2 , but have found it reads a bit low due the measuring point being positioned in an area of relatively high air speed within the vapouriser tube , the high air speed ( dynamic pressure) has a lower static pressure but same total pressure as the air exiting the diffuser .

We really need to position the P2 pickup in a "quiet corner" of the combustor where the air speeds are fairly slow , I've got my P2 pickup taken from behind the diffuser as theres a sizable gap between the diffuser wall and front of the flametube so air speeds are low in that area.

I also purchased a very good quality industrial gauge to measure my P2 , and that gauge produces a different reading to the gauge hooked up to the propane delivery line , the propane line always reads lower, but not the large amount you're concerned with , 0.2 Bar measured vs 0.5- 0.6 Bar from Map , my differences would only be ~0.1 Bar.

If we look at the comp map www.garrettmotion.com/wp-content/uploads/2018/05/Comp-Map-GTX5533-94mm-1.jpg the speed line at 38,000 rpm is reasonable "flat" over a fairly wide range of flow .

You may need to measure your T2 at your idle speed to determine compressor efficiency and see where it lies on the map.

Theres certainly a "mistake" in one of the readings , either the RPM or P2 to have so much difference

Hope this helps

Cheers
John

[praendy2203]

Sept 1, 2020 16:57:46 GMT -5 racket said:

Hi Andy

I've also used the propane delivery/injection plumbing to measure P2 , but have found it reads a bit low due the measuring point being positioned in an area of relatively high air speed within the vapouriser tube , the high air speed ( dynamic pressure) has a lower static pressure but same total pressure as the air exiting the diffuser .

We really need to position the P2 pickup in a "quiet corner" of the combustor where the air speeds are fairly slow , I've got my P2 pickup taken from behind the diffuser as theres a sizable gap between the diffuser wall and front of the flametube so air speeds are low in that area.

I also purchased a very good quality industrial gauge to measure my P2 , and that gauge produces a different reading to the gauge hooked up to the propane delivery line , the propane line always reads lower, but not the large amount you're concerned with , 0.2 Bar measured vs 0.5- 0.6 Bar from Map , my differences would only be ~0.1 Bar.

If we look at the comp map www.garrettmotion.com/wp-content/uploads/2018/05/Comp-Map-GTX5533-94mm-1.jpg the speed line at 38,000 rpm is reasonable "flat" over a fairly wide range of flow .

You may need to measure your T2 at your idle speed to determine compressor efficiency and see where it lies on the map.

Theres certainly a "mistake" in one of the readings , either the RPM or P2 to have so much difference

Hope this helps

Cheers
John

[praendy2203]

Sept 1, 2020 11:29:31 GMT -5 madpatty said:

Hi Andy.

I usually have my pressure P2 pickup right near the diffuser outlet from a hole drilled and tapped near where the diffuser axial straightening vanes are present.

Cheers.

[praendy2203]

Hi Patty, Hi John

Did already change the position.
No help! Seems to be all correct, but still a realy low indication.
Put out one screw from front cover and installed a small pipe. The pressure now is taken between diffusor plate and front of com. chamber.

Yesterday I spooled up to 55 000 Rpm and the gauge shows only 0,9 - 1,0 Bar.
70 000 is max Rpm due to the speed limit of the turbine wheel.
All works well together?

Stable idle
EGT is fine
Acelleration is Wow

For information:

The turbine and Ngv is from the Tornado fighter jet APU named KHD-T 312.

Will check wheter my housing and connection to the Ngv is leaking somewhere.

Stay tuned!

Cheers Andy

[racket]

Hi Andy

It is possible to be producing only 0.9-1.0 Bar at 55,000 rpm, but it would be well over in the high flow choke region of the map ,your T2 would be rather high at ~120 deg C , fuel flow would be high, along with thrust.

Do you have any area sizes for the NGV throats and wheel outlet throats ??

They'd give some indications of how good a match the comp and turb are .

If you had leaks large enough to lower your P2 readings the turbine temperatures would be very high as the engine tried to compensate for the lower mass through the turb stage as it tries to drive the higher flowing comp stage .
Cheers
John

[praendy2203]

Hi turbine builder,

there is a new video out from the

HIGH POWER SPAGHETTI TOPF 2020!

With help from John and different improvements it's getting better and better.

Thank you and enjoy!


youtu.be/3hRBWrEpHX4

[racket]

Hi Andy

Thats one fine engine :-)

Thanks for sharing the video with us guys , its inspirational.

You'll be needing to bolt the test stand down to the bench once up to full power , a couple of clamps mightn't be enough ;-)

Cheers
John

[praendy2203]

Hi,

some new stuff from my jet engine😊

Andy

youtu.be/JxL3Il_Mq-s