Picked up a pair of Schwitzer S500:s today.

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Johansson
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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Sun Mar 28, 2010 7:18 pm


racketmotorman
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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Sun Mar 28, 2010 9:43 pm

Hi Anders

Boys having fun :-)

Please, more info on how things performed , speeds etc

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Mon Mar 29, 2010 3:20 pm

racketmotorman wrote:Hi Anders

Boys having fun :-)

Please, more info on how things performed , speeds etc

Cheers
John
We sure had! Aprox. 200m down the track we lost oil pressure (noticed that afterwards from the helmet cam video) and blew the gasket between the comp housing and combustor, that made the afterburner flame out so the driver ran on the core engine for a total of 950m before he heard the compressor scrape the housing and shut the engine down.

A summary of the weekend with the helmet cam view: http://www.youtube.com/watch?v=5CxWS_yE5ws

The track was very bad and the kick runners not stable enough for any faster runs, but if the oil pump hadn´t failed he would have been able to reach the finish line and get a speed reading. He had a oil pressure safety switch but it must have been faulty since it didn´t shut the engine down when the pressure dropped. Bummer.

We checked the flame tube today and most of the colouring was on the upper part so it seems to work fine. The vapour tubes are light brown at the ends and not damaged at all, the flame tube lid has warped a bit and a small hole has been burned in it (regular SS sheet, 1mm). The syringe injectors had leaked fue around the base so there had been some combustion occuring between the flame tube and combustor casing, the high case temps was a sign of this and it might have been the cause of the burned hole.

With a better fuel management than this year (two days of struggling with faulty PWM-controllers) and the spark plug placed higher up on the combustor it will perform really well so next year will be interesting, in addition to this I have started building a gas turbine from a TV94 rotary assembly so if I can finish it in time and build a kick frame around it we should break some records next year. This year an old Solar gas turbine on a wooden kick frame reached 105km/h but the S500 turbine will eat that record for breakfast! :D

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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Tue Mar 30, 2010 4:39 am

Hi Anders

What sort of oil pump are you running ???

LOL......There was a bit of play in that shaft bearing at the end of the video :-)

A few more pics of the engine innards would be appreciated , flametube and evaps as well

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Tue Mar 30, 2010 7:40 am

A 2-stroke engine powering a hydraulic pump, the oil pressure was very stable but the engine was a bit of a struggle to start since it was directly coupled to the pump shaft. One idea why we lost oil pressure was that the oil level was below half tank and the bumpy track made the pickup suck air, the 2-stroke engine ran when he shut the turbine down so there must have been a problem with the delivery somehow.

I will ask my friend to take some pics of the engine once he starts to disassemble it.

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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Tue Mar 30, 2010 10:33 pm

Hi Anders

That was a bit of a bummer :-(

I've been looking thru my kart build notes and there is a mention in them that rather than the relatively shallow oil tank I used , it would have been advisable to have built a deeper tank so that any cornering G forces didn't cause problems with pickup cavitation , even though I used a pickup from an auto sump with its large diameter mesh filter positioned centrally in the tank and as close to the bottom as practical I still was concerned about air getting into the system .

The shallow oil tank was unavoidable due to the low mounting of the turbo in the kart , but my notes give the impression the oil tank needed to be shaped more like karting fuel tanks , a tall deep tank so as to give any entrapped air from the returning lube to escape before it got to the bottom of the tank and to the lube pickup filter, I did have a "de-airating" plate installed in the tank just above normal "running" lube level ( this is higher than static lube level due to the entrapped air ) , the plate was positioned so that turbo drain oil flowed across the perforated plate releasing some of its air before dropping thru the numerous 6mm dia holes in the plate .

Have you checked out my new lube pump pics on Yahoo DIY Gas Turbines , it uses a 12 V DC motor for powering a Subaru EA71 motor oil pump ( direct drive at ~900 rpm )

What sort of oil pressure were you running ??

I'll be looking forward to those pics :-)

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Wed Mar 31, 2010 7:13 am

The oil tank was two chevy small block valve covers welded together, and with an oil level below 50% it wouldn´t take much of a bump for the pickup to suck air. The new oil cooler bursted on friday during a test so I had to weld in a bypass tube instead, so oil temps must have been rather high at the end of the run.

We ran the turbine at 5 bar oil pressure, adjusted it down to 2 bar during starts for quicker spoolup.

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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Wed Mar 31, 2010 8:57 pm

Hi Anders

5 bar should have been enough , though when the oil heats up the pressure can often drop alarmingly low :(

All part of Rand D

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Thu Apr 01, 2010 3:08 pm

racketmotorman wrote:Hi Anders

5 bar should have been enough , though when the oil heats up the pressure can often drop alarmingly low :(

All part of Rand D

Cheers
John
That could be an explanation, but on the video it can be seen that the pressure gauge is on zero so the pickup must have been sucking air. No leaks in the system, the oil pump was running when he stopped and there were still 2/5 of oil left in the tank when the engine had cooled down.

The problem could have been that the oil lines are rather long 12mm hydraulic tubes that holds plenty of oil, so when the engine was shut off it looked like the oil level was fine. When the oil pump was running and the oil lines had filled up the tank might have been more or less empty... :roll:

We could have run an even higher oil pressure but the 2-stroke engine don´t like too much resistance and starts to sound stressed above 5 bar.

Cheers!

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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Thu Apr 01, 2010 9:45 pm

Hi Anders

The two stroke IC engine should have been more than capable of turning the lube pump , we only need ~200 Watts of energy to supply high pressure lube to even a big turbo ...............5 bar would be plenty of pressure ...........there could be a mismatch between lube system components ...........in such a cold environment you might need to be careful about over cooling the lube , it should be at >50 deg C going into the turbo at high power settings otherwise theres a chance that the lube flow rate will be down even though supply pressure is high , we need both high pressure and high flow rates .

Just the usual teething problems :D

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Wed Apr 28, 2010 8:16 pm

Here are the pics I promised, unfortunately I haven´t got a good pic from the side of the combustor but it doesen´t show anything of interest since a couple of hot starts has erased any heat pattern.
DSC05462.JPG
DSC05469.JPG
The burned hole in the lid is most likely a product of burning fuel on the outside of the flame tube, the spray nozzle internals had unscrewed itself so fuel had leaked all around the nozzle during the final runs. It can be seen on this pic of the combustor casing that it has been really hot.
DSC_0159.JPG
Here are a couple of pics from the weekend, we had a great time and will be back with the S500-turbine (among other engines) next year!
DSC_0018.JPG
DSC_0143.JPG
Cheers!

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Re: Picked up a pair of Schwitzer S500:s today.

Post by racketmotorman » Wed Apr 28, 2010 9:47 pm

Hi Anders

Thats been burning nicely :-))

Cheers
John

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Re: Picked up a pair of Schwitzer S500:s today.

Post by Johansson » Sat Feb 26, 2011 10:06 pm

Another year of racing, not even two weeks left now. Wish us luck! :D

Image

http://www.youtube.com/watch?v=0n6C6no5De8

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Re: Picked up a pair of Schwitzer S500:s today.

Post by luc » Sun Oct 30, 2011 5:22 pm

Johansson wrote:I´ve illustrated what it will look like at the first upstart.
Olovs jetspark 4.jpg
Olov jetspark.jpg
Came across this one while browsing the forum ... :lol:

I especially like the picture where the guy's balls stands few inches above that exhaust pipe ... :lol:

Plan on some ... "Cooking" ... He he he ... :lol:
Luc
Designer & Inventor

luc
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Re: Picked up a pair of Schwitzer S500:s today.

Post by luc » Sun Oct 30, 2011 5:25 pm

Johansson wrote:Another year of racing, not even two weeks left now. Wish us luck! :D

Image

http://www.youtube.com/watch?v=0n6C6no5De8
Damnnnn .... You guys have BALLS ... :shock:

Stainless Steel ones obviously ... :lol:

Nice work by the way ... :wink:
Luc
Designer & Inventor

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