APS/Ω Gas turbine bike build

[Peter Jack]

I'm just curious, is the engine rebuildable? It would be nice to put it on the shelf beside the trophies as a runner. 

Pete

[Mobacken Racing]

Thanks!

No more tshirts I am afraid, I haven´t broken even on the last batch so I´d rather spend my money on getting the bike race ready.

I don´t know how damaged the engine is, but I think I´ll just leave it as it is instead of spending time trying to fix it, the hot side is partially ceramic coated mild steel so I am surprised it has survived this long.

The results just came out, I laughed loud when I saw that I outran the 1500hp Dodge Viper...



Cheers!
/Anders

[grumm441]

Congratulations
I like that the hottest bike wins the coolest bike trophy
I also like that the half mile and one mile speeds are in kilometres per hour
G

[Mobacken Racing]

Congratulations
I like that the hottest bike wins the coolest bike trophy
I also like that the half mile and one mile speeds are in kilometres per hour
G

One thing a friend said was that it was pretty darn fast for a bike with an unsuspended rear, I have no idea how fast rigid frame bikes have run but I guess that the smarter bikers use suspension if they want to go fast...

[Mobacken Racing]

Tonight I undressed the bike to remove the engine and check it for wear.



I assumed the gas producer turbine would look like the Fukushima reactor core but to my surprise I couldn´t find any evidence of overheating, mostly it was soot that seems to have come from oil leaking past the rear seal.



Sharp turbine inducer tips, not what I expected to find!



The C20 power turbine was in a sorrier state though, one large crack and a couple of hairline cracks through the outer rim. Wear marks on the radial seals tells me that this must have happened while the bike was running and not while cooling down after the last run. No signs of cracks in the hub section which is a relief, lets just say that the turbine wheel stress relieved itself at 25.000rpm...



This is a good reminder to keep the temps in check, the new engine seems to be running at much more reasonable temperatures so I´ll just decide to not let the interstage temps go much past 750°C and this shouldn´t happen again.



Cheers!
/Anders

[Mobacken Racing]

I have been busy with other stuff lately but now it feels like the JU-02 project has priority again, during the last week or so I have been hooking up the bike to the test stand so now I am very close to having everything ready for a test start. I just have to fit the spark plug to the jet pipe to ignite the preheat propane. (a better location than in the combustor for several reasons IMO)



The 3D printer made itself useful again when I printed an exhaust cone for the leaf blower that fits snugly up against the compressor intake.



Cheers!
/Anders

[Mobacken Racing]

Tonight I shortened the oil pressure line as much as possible to get a true pressure reading from the sensor, I also fitted a spark plug boss to the jet pipe so that I won´t need a torch to light off the preheat.



Here it is installed, a few years ago I bought a couple of really small spark plugs from Ebay and one of those fitted perfectly.



Besides that I connected the P2 gauge and tested the preheat with oil pressure and the leaf blower at full speed, so now the engine is ready for a new test run!

I´ll try go fit a strip of reflective tape on the compressor hub so that I can measure RPM with the handheld tacho at different P2 settings, I´ll also give the load cell calibration another try because it would be very valuable to know how much thrust the engine is putting out at different P2´s.

Cheers!
/Anders

[Mobacken Racing]

I ran the engine again today with some assistance from my friends in Svarthålet Racing.



The engine started and ran perfectly until the oil pressure dropped and tripped the pressure switch. Whatta?!?!



My friends had brought a whole bag of tools so they measured the amperage draw over the battery while I ran the engine, turned out that the combined draw was close to 45A! No wonder that the engine shuts down as soon as the fuel pump starts to run hard around 2 bar P2...



I am thrilled to have found this problem at last, it has haunted me for several years so now I should be able to fix it by rewiring the bike and get me a better battery. Except for this the engine runs incredibly smooth, in this pic the engine is running at 1bar P2 and not a sign of color in the jetpipe!



During the last test run the return pump suddenly failed and caused a spray of burning oil out of the exhaust, no harm done except that my workshop rug won´t ever smell the same again...



Ooops, I almost forgot the video.

https://youtu.be/E0ON5qUeLlU

Cheers!
/Anders

[manta22]

Anders;

 It is very risky to run an engine indoors. One of the members of this forum burned his garage and his Camaro when the carburetor backfired. 

Regards, Neil  Tucson, AZ

[Mobacken Racing]

Anders;

 It is very risky to run an engine indoors. One of the members of this forum burned his garage and his Camaro when the carburetor backfired. 

Regards, Neil  Tucson, AZ

That is a good reminder Neil, unfortunately my engine stand weighs a ton so I just have to keep an eye out and lots of fire extinguishers nearby.

The cat was looking a bit worried though...



Cheers!
/Anders

[Mobacken Racing]

https://youtu.be/jn6naLudmHs

[nanno]

The cat was looking a bit worried though...

Clever Kitty 

[WOODY@DDLLC]

Anders, I don't care what the cat says!!
You have the coolest hottest and fastest leaf shredder in the world! 

[Mobacken Racing]

Anders, I don't care what the cat says!!
You have the coolest hottest and fastest leaf shredder in the world! 

Don´t forget loudest, it puts out a roar even at these moderate RPM´s that puts the old JU-01 to shame. I am really eager to hear (and feel!) what it sounds like at full throttle.

[Mobacken Racing]

Still waiting for the new LiFe battery to arrive so meanwhile I am catching up on other hobby related stuff. Nevertheless I got around to fit the new scavenge pump to the test rig tonight and it has no problem at all keeping up with the oil flow at its rated 6x flow capacity.



One thing I noticed was a slight smell of hot wires from the bike after the pumps had been running for a minute, I´ve been using very moderate cable areas so I decided then to rewire all of the big consumers before I run the engine again. Probably some half arsed wiring just for the test rig running but if it does the trick I´ll rewire the bike cable harness later.

Cheers!
/Anders