APS/Ω Gas turbine bike build

[manta22]

Patrick;

If that table is using amperes RMS, then it is dead wrong. On the other hand, if it is showing the average AC value, which most AC voltmeters measure, then I can believe it.

Regards, Neil  Tucson, AZ

[Mobacken Racing]

I charged the new LiFePO4 60Ah battery over night and took it out to the workshop after dinner, just for fun I compared the weights of the new battery and my old Deka Dominator. I am lowering the bike weight by 6kg by doing this battery change, great!



So, I hooked the battery up and started the pumps. The first thing that happened was that the 30A fuse for the oil pump blew after like 5 seconds, this indicates that the battery is giving more juice to the pump than before. I replaced the fuse holder with a length of 6mm2 wire and tried it again with better luck. The + cable gets just noticeably "warm" but nothing that I need to worry about. Might add a larger fuse later.



Anyway the oil pressure is rock solid, nothing like before when the pressure started to drop after a dozen seconds or so. Success!

Cheers!
/Anders

[Mobacken Racing]

Hi guys!

I test ran the engine today with the new battery, the oil pressure is much more stable now although the prolonged test heated up the oil until the pressure started to fall down to 3kg.

I ran the engine up to 3bar P2 where the engine was really screaming, my trusty foam plugs was nowhere near enough hearing protection so I need to use my artillery ear muffs on top of them next time. You can see the flag starting to wave from the air flow when I throttle past 2 bar, and the shed doors started to close from the jet stream passing by.

Exhaust temps were in the high 650°C region at 3bar P2, perfect since the temps will go up a bit when I push the engine toward 4 bar later. When I shut the engine down a compressor rub can be heard, I will investigate it when I disassemble the engine later. Shaft play feels ok and nothing is rubbing now so hopefully is isn´t anything serious.

https://youtu.be/zG3I_CijEjo

Cheers!
/Anders

[Peter Jack]

Another amazing performance Anders. Well done. 

Pete

[manta22]

Excellent!   

Regards, Neil  Tucson, AZ

[Mobacken Racing]

Thanks!

I am slowly getting there, the goal is to have the engine running at 4bar for a full minute with stable oil pressure and 700-ish°C exhaust temps, then it is time to install it in the motorcycle. I won´t be rushing it since I am rather enjoying this relaxed period of testing and tuning.

[Mobacken Racing]

Happy new year folks! Lately I´ve been working on a turbofan powered ice yacht with a friend and we have a shitload of work to do before the race two months from now, but I have still managed to get a few things done on the bike.





I have made a new oil regulator and fitted larger bore AN8 oil lines since the old AN6 lines were restricting the flow, and with a change from 0w30 to 20w50 oil I now have a very stable 5kg oil pressure at the entry of the engine.





When I have built the turbofan engine and installed it in the ice yacht chassis I have some room on the work bench to disassemble the JU-02 engine and inspect it after the runs, I will also check if I need to open up the axial compressor clearance a tenth of a mm or two since I heard some rubbing during the last run.

Cheers!
/Anders

[thefrenchowl]

Happy New Year, Anders, and fingers crossed...

Patrick

[Mobacken Racing]

Happy New Year, Anders, and fingers crossed...

Patrick

Thanks Patrick!

[Mobacken Racing]

I dismantled JU-02 this evening to check the wear and tear out.



The combustor looks perfectly fine, no signs of hot spots or uneven combustion on the outer liner.



The turbine blades has wear marks from some piece of metal that has come loose from inside the engine and embedded itself in the turbine cover, I saw this when the engine was still assembled so no surprise there.



The compressor wheel rubbed its cover during the last test run when the oil pressure ran low, the exducers have some marks but nothing deep so I can smoothen them out with a needle file.



Here the compressor rub can be seen in the cover, the castings must have settled down some during the runs since it only rubs on one side despite an even clearance before I ran the engine. I´ll give the compressor a bit more clearance to avoid any further contact there.



All in all a very satisfying teardown so far, I´ll take the rest of the engine apart another evening to check the inner liner out but I don´t think I will find anything alarming.

Cheers!
/Anders

[thecarfarmer]

Been away from the website here for a while (life stuff); really happy to see you hit your 300kmh goal - somewhat less happy to see the failure on th JU-01.

But its replacement is on deck, right?

-William

[Mobacken Racing]

Been away from the website here for a while (life stuff); really happy to see you hit your 300kmh goal - somewhat less happy to see the failure on th JU-01.

But its replacement is on deck, right?

-William

Thanks William! The "death" of JU-01 was in fact not really the disaster I expected it to be, no real damage was made to the engine except for a cracked outer rim on the free power turbine. If I wanted to the engine would be operational again in a month or two, no big deal.

But, since I have pushed the old JU-01 engine to its limits and a bit beyond I see no reason to spend any more effort on it, with JU-02 well on its way I will focus all my time tuning it and doing test runs until it can be run at full power for at least 10 minutes. Then I can start the work of fitting the gas producer in the bike chassis and hopefully end up with a 250+hp gas turbine motorcycle that will be capable of 230-240km/h runs at the standing mile.

Cheers!
/Anders

[Mobacken Racing]

Lately I´ve considered and reconsidered the oil pressure system for the bike.

The mechanical regulator my friend Olov has built for the jet kick as been rock solid, and the old bike regulator had pretty small bore so I am becoming more and more sure that a high flow regulator would solve my problem. So, for now I´ll put the PWM controller idea on the shelf and test a big bore regulator first.



I spent a couple of hours on it last night, here I am milling the regulator piston bore.



This is as far as I got, a spring loaded nylon piston that gradually opens up the return port should provide a stable oil pressure.



I have found an oil resistant transparent hose reinforced with a steel wire coil that I plan to use for the return lines from the regulator and the engine scavenge pump, this way I can visually confirm that the oil is flowing like it should.

Cheers!
/Anders

[Mobacken Racing]

Since the last update I have fitted two large bore hose fittings to the oil tank front baffle, this is for the oil returning from the new regulator and the engine drain.



I have also had the rotor sent away for balancing to make sure that the rubbing marks didn´t upset the rotor dynamics, I was sponsored with the job from the great guys as Turbotech AB here in Sweden!



Cheers!
/Anders

[Mobacken Racing]

With the rotor back from balancing I got an inspirational boost and spent both this morning and evening in the workshop.



The first job was to make an angled oil return fitting since a straight one would interfere with the fuel tank once the engine is back in the bike chassis.



It turned out to be a very snug fit for the drain hose, this will work perfectly!



A better view of the oil return line.



And yet another one with the diffusor plate in place.



With that done I spent another couple of hours this evening making the air impingement nozzle for scuba tank starting, after some serious eyeballing I drilled a hole in the engine cover and welded a pair of M6 stainless screws to it.



Then I used a stainless 6mm OD pipe as the impingement nozzle and made this contraption.



Here it is fitted to the engine cover, this is located on top of the engine which is the best location when the engine is installed in the bike.



I managed to squeeze my mobile phone into the NGV to take this pic of the impingement nozzle end sitting flush with the NGV vanes.



Cheers!
/Anders