Author Topic: APS/Ω Gas turbine bike build  (Read 930986 times)

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Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #645 on: August 13, 2014, 05:08:12 PM »
Thank you very much Racer! :-)

Finished the tachometer mods today, I bought a cheap handheld unit, removed the diodes and the lens and made a separate housing for them with a length of cable to the unit.



I fitted the probe inside the air box and painted a white dot on one compressor wing, it works fine when rotating the engine by hand so hopefully it will work with higher revs as well. I will try it with the scuba tank tomorrow when the paint has dried.



Cheers!
/Anders

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #646 on: August 16, 2014, 05:13:41 PM »
I had to modify the optical pickup a bit to get it to work reliably, the lens was messing things up so I removed it and made some other mods tonight.



With the diodes closer to the compressor wheel it reads the revs perfectly, I tested with an almost empty scuba bottle up to 6000rpm and not a single hickup so I think this will work. Everything is securely mounted so it shouldn´t end up getting sucked into the compressor wheel...



With that done I started making the test exhaust pipe, earlier I had spend a few hours turning a v-band flange from a piece of stainless in the lathe and with a 4" stainless pipe bend I got to work.



Before I welded it I clamped the flange down firmly to avoid any warping of the thin flange, it turned out really well in the end.



Here the finished pipe is mounted to the engine, the TOT probe is fitted exactly as it is on the power turbine NGV to make sure I am reading the same temp. It can differ somewhat depending on its location if the combustion is uneven. A pitot tube will be injected through the end of the pipe to measure the absolute pressure in the exhaust.



Cheers!
/Anders

Offline tauruck

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Re: APS/Ω Gas turbine bike build
« Reply #647 on: August 17, 2014, 01:16:51 AM »
Rocket science!!!.

My Danish buddy also does stuff I don't understand but I nod and pretend. :-D

Anders, I always get educated here. :cheers:

Offline wobblywalrus

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Re: APS/Ω Gas turbine bike build
« Reply #648 on: August 17, 2014, 01:57:16 AM »
That exhaust will be added thrust if you can figure out how to shoot it out of the back end.

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #649 on: August 17, 2014, 08:07:59 AM »
This exhaust is only for static testing, I need to gather some data from the gas producer to figure out how to cure the temp issue.

The energy in the exhaust is spent after passing through the power turbine stage so there is nothing to gain from directing the exhaust backwards except perhaps a slight decrease in drag from exhaust no longer blowing out at an angle from the bike.

Offline bbarn

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Re:
« Reply #650 on: August 17, 2014, 12:43:31 PM »
Anders, I am going to challenge your statement of the exhaust being spent. On a PT6-135A turbine used on Piper Cheyenne you pick up around 35 pounds of thrust per exhaust port (x4).

It is a similar setup (turbo shaft) / design, there has to be some amount of gain. Even if it is only to fill in the separation drag, there has to be something that can be used as a benefit. I doubt the air coming out of the exhaust is moving at a zero velocity too.
I almost never wake up cranky, I usually just let her sleep in.

Offline Mobacken Racing

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Re:
« Reply #651 on: August 17, 2014, 02:09:08 PM »
Anders, I am going to challenge your statement of the exhaust being spent. On a PT6-135A turbine used on Piper Cheyenne you pick up around 35 pounds of thrust per exhaust port (x4).

It is a similar setup (turbo shaft) / design, there has to be some amount of gain. Even if it is only to fill in the separation drag, there has to be something that can be used as a benefit. I doubt the air coming out of the exhaust is moving at a zero velocity too.

You are right, but given that the 135A has 5x the power output it leaves me with less than 30lbs of residual thrust. Nothing that can make any difference at all except melt the read fairing if the jet exhaust gets too close to it.

I will direct the exhaust at an angle backwards later when the fairings are made, perhaps 45° or so, any more and the bend might restrict the exhaust flow plus I risk heat damage to the rear of the bike.

Today I made the pitot tube so now everything is set for the upcoming test, I´ve even filled up the scuba tanks.



I used a 6mm 316 stainless tube reaching 2cm into the tube, I left a length of tube on the outside so the rubber hose would have a chance of surviving the heat.



And here is the gauge, ready for action! If the weather clears up I can do a test during the first part of the week, on thursday I will go to Tierp to watch the dragracing EM event! :cheers:



Cheers!
/Anders

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #652 on: August 18, 2014, 03:42:14 PM »
To get a full video log of what is happening with the engine during the test I moved the pressure gauge I already had on the side of the air box up to the triple tree visible the Gopro camera.



I will be looking for signs of under pressure in the air box, this would indicate that the air box is restricting the incoming air while running the engine stationary. It will be very interesting to go through the video after the run to see if and when the P1 (pressure before the compressor) starts to change, and when I start doing high speed road tests I hope to see slightly higher pressure thanks to the ram air.



Cheers!
/Anders

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #653 on: August 30, 2014, 05:20:38 PM »
I did the static test today, the crappy english is only for you guys. :)

http://youtu.be/bthi6eW4BgM?list=UUrsqamKC_NUQP-_7qzVdWCw

The Gopro video of the gauges.

http://youtu.be/qJvnafqw38Y?list=UUrsqamKC_NUQP-_7qzVdWCw

Some closeups of the gauges at 15°C and 1018hPa ambient pressure:

0.4bar (32.900rpm):


1.0bar (47.900rpm):


1.5bar (55.000rpm):


2.0bar (no RPM reading):


2.5bar (no RPM reading):


Too bad the reflective paint on the compressor nut came off, but I´ll fix that before the next test.

Cheers!
/Anders
« Last Edit: August 30, 2014, 05:41:38 PM by Mobacken Racing »

Offline tauruck

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Re: APS/Ω Gas turbine bike build
« Reply #654 on: August 30, 2014, 05:36:55 PM »
Anders, you have way too much fun. :-D

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #655 on: August 30, 2014, 05:43:12 PM »
Anders, you have way too much fun. :-D

Indeed, by now I do have a couple of eventful Saturdays in the back of my mind.  :-)

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #656 on: September 17, 2014, 01:52:21 PM »
I picked a new engine up last Saturday so now I have a bit less elbow space in my workshop... :-D





Cheers!
/Anders

Offline bbarn

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Re: APS/Ω Gas turbine bike build
« Reply #657 on: September 17, 2014, 03:16:05 PM »
Well Anders, I am glad you didn't get something big, loud and obnoxious!  :-D

"What are your plans for this?" he asked with great anticipation!

I just saw one of these engines in an old ('62 or '63) T3 parked in the Enola Gay hanger.
« Last Edit: September 17, 2014, 03:18:10 PM by bbarn »
I almost never wake up cranky, I usually just let her sleep in.

Offline Buickguy3

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Re: APS/Ω Gas turbine bike build
« Reply #658 on: September 17, 2014, 03:47:07 PM »
  Wow! Anders,
   The bike that that goes in should be quite a build. Looking forward to reading about that one.  :wink:
   Doug  :cheers: :cheers: :cheers:
I keep going faster and faster and I don't know why. All I have to do is live and die.
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Offline grumm441

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Re: APS/Ω Gas turbine bike build
« Reply #659 on: September 17, 2014, 06:59:44 PM »
you're going to need a bigger bike
G
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