APS/Ω Gas turbine bike build

[bbarn]

We need video WITH SOUND! There are very few things (in my book anyhow) cooler than the sound of a turbine engine starting up.

[Captthundarr]

We need video WITH SOUND! There are very few things (in my book anyhow) cooler than the sound of a turbine engine starting up.

AGREED

[gkabbt]

We need video WITH SOUND! There are very few things (in my book anyhow) cooler than the sound of a turbine engine starting up.

AGREED

Not meaning to jack Anders thread but I was at the start Sunday morning in Wilmington when the Zanefeld TIII liner was started and made it's second pass.
Turbines are WAY cool!   

Now back to your regularly scheduled Anders thread!   

Gregg

[Mobacken Racing]

Don´t worry guys, there will be plenty of video footage taken during the test.

I couldn´t resist to go back outside last night and do a start cycle without adding any kero. I removed the propane regulator so I can start the engine directly without any need for a preheat fan.

I tested several times by opening up the scuba tank so the rotor starts turning, then I craned the propane tank fully open and pushed the ignition button so it lit off. Then I opened the scuba tank fully and had the rotor at its full "dry" revs with the propane heating up the engine internals very fast.

Guess if I was tempted to start the fuel pump PWM and crank the engine up to idle inside the workshop...

After the test I checked for any oil pooled up inside the engine but didn´t find a drop, things are looking mighty promising for this weekends test!

Cheers!
/Anders

[Mobacken Racing]

I figured out today that I needed to move the PWM controller from the position on top of the battery to the handlebar if I want to throttle the bike while riding it, so an hour ago I went outside and did just that.



After that I filled oil in the gearbox, fitted the fairings and went over the bike to find any loose bolts.



Here you can see the chain in place.



The last two evenings I have had the diving compressor running to fill my two 15 liter scuba tanks, it is a bit worn so the pressure doesen´t get higher than 170 bar but that is enough to get the bike started.



As you know I´ve tested the preheating and air start already so now everything is set for the test on sunday morning. If everything goes as planned I will have a video on youtube before I go to bed.

Cheers!
/Anders

[Mobacken Racing]

I just remembered that I haven´t weighed the bike so I went outside with the bathroom scale to find out how it compares to a modern sportbike.



Weight on the front wheel is 82.5kg, not bad. What about the rear?



It weighed in at 95.8kg, much thanks to the heavy battery and cast iron gearbox. Add up the numbers and you get 178.3kg with 15kg of fuel and oil in the tanks, remove that and you get a dry weight of 163.3kg!

Sure, I have to strenghten the frame somewhat and make a rear fender etc. for it but those things will only add a couple of extra kilos. It is actually possible to reach a power/weight ratio of 1:1 or even better after the engine has been tuned in!



As a comparison the Ducati 1198 has a dry weight of 171kg and I bet its gearbox isn´t made out of cast iron either.

Cheers!
/Anders

[Mobacken Racing]

Today was D-day, my friends had gathered and the BBQ set for a kerosine smelling lunch!



As you can see we went all the way and made camp with my new race tent, always good to get some practice in raising it before we have to do it in the middle of the night in full snow storm in Orsa...



With rain fast approaching we decided to kick of the test immediately, scuba tank and propane all set so I gave her a spin.



Here is the video from the day, see it first to better understand the comments below.

http://youtu.be/1GGNreBzPkY

It was a bugger that the switch broke, but looking at the video footage I think something was wrong even before I lost oil pressure. During the first run I had a stable exhaust temp around 600°C or so (mental overload so can´t remember exactly) but then the temps started to climb fast and then the fuel pump shut off due to the lack of oil pressure. (a pressure switch trips the fuel pump if the oil pump stops)



This is the piston ring seal after the teardown, my guess is that a rotor out of balance combined with a too tight clearance for the piston ring seal in its housing made it rub against the wall until the piston rings overheated and jammed up everything.



Luckily I have two bearing sets on their way so with a new piston ring seal and a somewhat opened up seal housing it shouldn´t rub any more. I will also send the rotor away for rebalancing and point out that the compressor wheel and the shaft must be grinded so I can align them perfectly during assembly.



Right now I have no clue how they were aligned during balancing so they can be assembled way out of balance for all I know.



Despite this minor setback I am satisfied with the test, the starting procedure was flawless (it would have been easier with three hands though) and from what I remember of the idle exhaust temp the power turbine section must be correctly sized.

The shaft looks ok though I will measure it again with the indicator clock in the lathe before I send it away for balancing, the comp wheel throw in the video was from the piston ring seal rubbing unevenly in its housing and not a bent shaft. Pheww!

Cheers!
/Anders

[bbarn]

Anders - I have been checking all day anxiously waiting to see how your test went. It is great to see you and your friends gathered around enjoying yourselves.

While the test wasn't flawless, it certainly was a complete failure either. It looks like a minor setback in a stunning build. Given the expertise you have demonstrated thus far in the build, I have every confidence you will sort it out and wow us with your fix!

Keep at it, we are all rooting for you! I have complete confidence you will be successful!

[Vinsky]

This is a story of a modern day Burt Munro. I hope to see it on the salt some day.

[Tim Thomssen]

Awesome build, thanks for sharing!

For the switch you might try an old drag bike trick.  Get a heavy duty Caterpillar or similar HD implement  double throw switch and wire both sides in parallel for some built in redundancy.

Cheers!

Tim

[Mobacken Racing]

bbarn: Thank you very much, my friends are the best so for every setback we share a laugh and start discussing how to solve it.

Vinsky: I will bring the bike to the salt even if I have to row it over the ocean myself.

Tim Thomssen: Thanks! That is an interesting solution, something has to be done for sure because I don´t want a component failure happening again. Hopefully the turbine shaft can be reused, I will go outside now and measure it.

[charlie101]

A bit disturbing when the engine breaks because a lack of oil supply, a remedy would be to have a spring loaded oil pressure tank after the oil pump that supplies the bearings with oil during spool down in the case the pump will give up. It should also function as a security if the pump temporary loose oil supply when you don't have baffles in the oil tank and is reducing speed or jumping around on an uneven track. No need to risk the engine because a unplanned occation as a flat tire or veering off on some bumpy track side. Also any battery can break, and risk that happen again even with larger sealer play?

[Buickguy3]

  Any chance that there isn't sufficient end gap on the seal rings and they are seizing up in the bore as the heat builds? What the heck do I know? I only work on old Buick straight eights. Love this build of yours. Been following it from the beginning. Maybe it's beer time.
  Doug 

[manta22]

A small oil accumulator should provide a constant oil pressure, even for a while when the engine is spooling down.

[Glen]

A small oil accumulator should provide a constant oil pressure, even for a while when the engine is spooling down.

Neil is correct on this.