Author Topic: APS/Ω Gas turbine bike build  (Read 931095 times)

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Offline octane

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Re: APS/Ω Gas turbine bike build
« Reply #315 on: October 26, 2013, 03:11:41 PM »
While I am waiting for some parts for the bike a friend and I (the productive core of Mobacken Racing) have started building a new jet-kicksled for next years landspeed on ice race at Orsa, twin Schwitzer S500 based afterburning gas turbines producing >1000N of thrust with the driver standing on two 5mm thin spring steel runners...  :-)



With everything dialed in we hope to run at lest 160km/h, hopefully even faster. Should be an interesting ride, two years ago Olovs leg caught fire from the radiant heat from the old jet kicks afterburner, with almost three times the thrust both legs and a fair bit of his behind are in danger... 8-)

Cheers!
/Anders

I'm telling you : the Swedes are nuts !
Absolutely brilliant !!!!!!!!!!!!!!
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #316 on: October 26, 2013, 03:23:56 PM »
Have you guys ever thought of just shooting yourselves?

Nahh, a gas turbine harakiri is sooooo much cooler. :-)

Offline octane

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Re: APS/Ω Gas turbine bike build
« Reply #317 on: October 26, 2013, 03:24:23 PM »
Anders: you gotta' come to Copenhagen and we'll go visit a friend of mine; Claus
( who will do the welding of my frame ).
He's part of this here project which is quite mind-blowing and right up your alley,
rocket engine and all:

http://youtu.be/1i3HDv2s7io

The nutters all do it in their spare-time and just for the fun of it.

First they made a small freaking submarine....that worked quite well...
then a BIG freaking submarine...that worked well too.
Where do ya' go from there ?....into space of cause !

They are doing brilliantly:

They've just been awarded The Fédération Aéronautique Internationale (FAI) Breitling Milestone Award 2013:

Copenhagen Suborbitals have achieved an outstanding performance and contribution to astronautics by designing, building and launching the world’s first amateur built full size rocket with full computer control and steering – based completely upon amateurs and donations.

The results has been achieved from nothing – and this has demanded the highest level of vision, patience, and creativity, organizational and technical skills in different areas from computer programming to economics and funding.

The way of thinking, working and the way of sharing information in aeronautics has never been seen before, and can change the way we interact with others and the way we travel in spac
e.”
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline octane

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Re: APS/Ω Gas turbine bike build
« Reply #318 on: October 26, 2013, 03:26:58 PM »
Click:

http://www.copenhagensuborbitals.com/

I'm sure you'd enjoy a visit.
They are just around the corner from my place.

.

OK then;  the Danes are nutters too !
« Last Edit: October 26, 2013, 03:29:10 PM by octane »
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #319 on: October 26, 2013, 03:39:56 PM »
I´ve followed those guys for quite some time now, I love what they are doing and that they are doing it on a "shoe string" budget and not an infinite well of tax money like NASA. Please tell them that Mobacken Racing are huge fans and wish them all the best! :-)

Offline octane

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Re: APS/Ω Gas turbine bike build
« Reply #320 on: October 26, 2013, 03:51:02 PM »
Will do Anders:

For those digging this kind of things, this is interesting;
These nutters are building everything from scratch in an un-heated workshop  and it's all
quite simple....NOT :

 http://youtu.be/p6BC1QfA0Ug?t=12m23s


.
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #321 on: October 29, 2013, 05:31:16 PM »
While waiting for some parts to arrive I made up a list of things to do before the engine can be reassembled, you can probably not read it but it says rebuild the oil return, fit new Hobbs oil pressure switch, true the compressor spacer, make new piston ring seal housing and send the rotor away for rebalancing.



My friend Lars-E (one of the V1 pulsejet sled guys) offered to true the comp spacer in his grinder at work, it lost a little shape from the heat when the piston ring seal got destroyed so it needs some work.



Tonight I have been making parts for a new and improved oil scavenge line, the old one was made out of hydraulic tubes with metric threads cut so deep that I constantly worried that they would snap when the external AN-connections were torqued in place. The new steel ones have UNF threads that aren´t nearly as deep as the metric threads, I´ve also added a flange on the inside so they can be torqued without stressing the connection tubes.



Here I have just cut the old tubes to fit the new steel ones, a look at the workshop clock told me that time had rushed by so I had to call it a night. When I got back inside and happened to look at the kitchen clock I realized that the workshop clock was still running on summer time and therefore an hour ahead. Damnit! :)

Cheers!
/Anders

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #322 on: November 04, 2013, 05:04:03 PM »
I finished the oil scavenge lines today along with some other stuff.



First of the two scavenge tubes mocked up.



And here they are welded in place!



With the scavenge line finished I modified four M10 stainless insex bolts in the lathe, they will be used to bolt the diffusor housing to the shaft tunnel instead of the abused 12.9 bolts I´ve used earlier.



Last week I got the Hobbs adjustable pressure switches I ordered.



Here one of them is fitted to the oil filter holder, now I can set it so that the fuel pump shuts off below 3 kg oil pressure. It will spare the bearings compared to earlier when I had a 0.2 kg standard automotive oil pressure switch.



Cheers!
/Anders

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #323 on: November 06, 2013, 02:26:46 PM »
My friend Lars-E offered to grind the compressor spacer flat since it got a bit distorted from the heat when the piston ring seal rubbed its housing, he emailed these pics last night to show that he was finished.



Here is the finished spacer with measurement protocols before and after the grinding, as you can see the spacer was out well over one hundredths of a mm and close to the shaft centre it would bend the shaft badly.



I removed the piston ring marks from the piston ring housing in the lathe and found that it can be used again, great news!  :-)



All I am waiting for right now is the bearing kits I´ve ordered. When I get them I can assemble the entire turbine shaft, mark every part up for alignment and send it away for balancing!



Cheers!
/Anders

Offline wobblywalrus

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Re: APS/Ω Gas turbine bike build
« Reply #324 on: November 06, 2013, 02:56:48 PM »
Anders, in reference to the welded oil lines connecting the little black box to the big aluminum round thing.  It would be a good idea to pressure test that system if you can at the extreme ends of the expected operating temperature range.  The aluminum disk will have quite a bit of expansion and contraction when it heats and cools.  This might affect the seal.

In addition, the design should account for the contraction and expansion to prevent overstressing the oil lines and the resulting fatigue failure.  Some times we put a curly-Q loop in an oil line so it will not be overstressed.     l

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #325 on: November 07, 2013, 05:19:46 PM »
Anders, in reference to the welded oil lines connecting the little black box to the big aluminum round thing.  It would be a good idea to pressure test that system if you can at the extreme ends of the expected operating temperature range.  The aluminum disk will have quite a bit of expansion and contraction when it heats and cools.  This might affect the seal.

In addition, the design should account for the contraction and expansion to prevent overstressing the oil lines and the resulting fatigue failure.  Some times we put a curly-Q loop in an oil line so it will not be overstressed.     l

The oil lines are suction lines so a slight under pressure is all it will ever have to endure.

What you cannot see in the pics is the combustor can that takes up almost all space inside the engine so it is impossible to add any flex loops or similar to the line. I understand your concern but I´ll take my chances and hope that it won´t be a problem. If cracks start to appear I will have to rethink but for now this will do.

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #326 on: November 19, 2013, 04:17:58 PM »
Not much have happened on the bike during the last weeks, lots of work away from home and a pair of beer trips as well has stolen all workshop time from me. Space is even more cramped now since I brought my "daily driver" Triumph bobber in from the cold to get the tank welded and exhaust pipes modified a bit.



Tonight I felt I had to do something while waiting for the rotary parts to arrive from balancing, I took two JIC 9/16" steel couplings and made the scavenge line couplings from them.



Here they are fitted, way better and tighter fit than with the old couplings so this will work great! :-)



I mailed the newly grinded compressor spacer to the balancing company today, unfortunately the bearing kits they ordered for me didn´t contain all the parts needed so it will take some time before they get the new sets and can balance the complete rotor.

Cheers!
/Anders

Offline tauruck

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Re: APS/Ω Gas turbine bike build
« Reply #327 on: November 19, 2013, 04:41:39 PM »
That's a lot of work there and I'm trying really hard to understand what goes on in that turbine but I enjoy the updates. Thanks. :cheers:

Offline wobblywalrus

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Re: APS/Ω Gas turbine bike build
« Reply #328 on: November 20, 2013, 01:25:42 AM »
I know, Mike.  It is interesting and confusing.  That must be 'cause it is different than what we usually see.  People tell me these turbines are much simpler than our reciprocating engines. 

Offline Mobacken Racing

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Re: APS/Ω Gas turbine bike build
« Reply #329 on: November 22, 2013, 03:24:57 PM »
They really are quite simple, the calculations behind building one are massive but there is only one moving part in the engine which makes them relatively easy to understand.

If I were better at 3d-CAD I could make a model of the engine that would better show exactly how it all goes together but as it is you have to try to imagine it somehow.