Landspeed bike with DIY gas turbine

[metiz]

Great effort! It's a real shame something so "minor" (using the term loosely) caused your problems. I don't know enough about turbines to realy know what's going on, is this a major problem or can it be fixed relatively easy?

Regardless, great job so far! the bike looks great in the sunlight.

[rythmnbls]

Just saw the video too, the bike looks really good, a shame Mr Murphy showed up, now that he has - you can focus on burning kero the best way possible

Any chance of another test before the snows arrive ?

Steve.

[Deleted]

Hi Anders

i dont know if you have a relay controling your oil and fuel pumps, but what i have done as well as running pressure switch on oil line in to fuel pump, but i use power from oil pump relay output split to oil pump then power to fuel pump relay with it, so if not only fuel shuts off at loss of oil pressure but also if power for oil pump fails. al so try and get pick up to pressure switch as close as possible to oil pump, I dont know if this helps

[racket]

Hi Anders

BUGGER !!! ..................thankfully only at low power and not moving ........................LOL, say hello to my mate Murphy for me will you , he's been a "participant??" at a fair few of my engine tests too :-) ..............oh , those never ending bearing failures and rotor replacements with FM-1 :-(

Is the new insert in the diffuser "coloured" all around or only on one side , an "all around" is "best??" , if "one sided" things might not be concentric .

Piston ring gap is generally pretty small, less than 0.1mm , so not much scope for increasing the diametric clearance between ring holder and the insert.

Out of balance is probably the most likely culprit as you've already said, once the lube film started to break down with the loss of pressure she started to wobble around , ..............there was that "tinkling??" sound as it spooled down , comp blades touching the housing maybe .

Are you going to completely disassemble the engine to check for other possible problems ??

Lots to think about tomorrow.

Thanks for sharing the video .............heh heh , nice to see you dressed for the occasion :-)

Cheers
John

[jettoymaker]

Hi Anders,

Just spoke to John and had a look at the video...I'm so sorry it went that way. Are you running a Hobbs switch for pressure shut of and if so, what is the shutoff pressure? The one on B1 is set to 45psi shutoff.

About to start another round of tests this week as B1 is back together again, but no longer feeling so good about it because you should have been in the club too. I don't know how you kept your composure... I spat the dummy big time when the power turbine cracked after overtemping B1 on a fuel adjustment run. I hope it's all easily fixed so you can ride before the weather wont let you. You've put in so much hard work, you deserve and need to get over the line.

R&D is the cruelest bitch...just ask John

Regards, Andrew

[Johansson]

Thanks for the kind words guys, I am not at all sad about this but eager to continue the development. It takes more than this to annoy me after all the years of R&D. *LOL*

It is hard to tell when the bike will be ready for another run, I don´t know when the bearing kits will arrive and the rotary assembly will have to be sent away for balancing so all I can say is that it won´t be ready before snow falls.

Andy: That is a great idea! If I connect my scavange pumps as well I will know that they are running, right now I can only guess once the engine is making noice.

John: The insert has more wear at 4o´clock looking at it from the intake side but there are wear marks all around it.

I will assemble the shaft with thrust bearing and the comp spacer and measure the shaft in the lathe to see if anything is bent with the shaft in tension.

It sure feels like the comp allignment is the problem, during the last bench test it ran perfectly smooth and the only thing that differs from that test is that the rotary assembly has been taken apart and put back together again.

Andrew: I have a simple oil pressure switch that closes if there isn´t any pressure at all, no fancy adjustable one yet. Might have to get one though.

As I said no big deal for me, as long as the housings and shaft are OK then it is just a minor hickup in the build process. =)

I´ll go through the engine more thoroughly some evening, but keep any ideas coming guys.

Cheers!
/Anders

[racket]

Hi Anders

Heh heh , thats the spirit, just a minor hiccup in development :-)

Could the "4 o'clock" rub be because of "hydraulic??" pressure pushing the bearing across the shaft tunnel bore when the lube supply was breaking down , is the lube port feeding the bearings at 10 0'clock , if not then there might be a slight variation in concentricity , perhaps turning up a gauge tool to check alignment of bearing housing bore and piston ring bore in the diffuser housing might throw some light on things .

It'll be interesting to see how the bearing housing bores coped with the lube failure, hopefully no damage .

Yeh , take the autopsy slowly , one part at a time ............with a bit of luck she'll only need a cleanup, some new bearing bits and a rotor balance to get you back in business for next year when the snow clears :-)

More pics of the bearing bits as you pull them out please, they'll be invaluable for future reference by us guys who like "brass bush" bearings ;-)

Cheers
John

[Johansson]

Oct 7, 2013 3:28:16 GMT -5 racket said:

Hi Anders

Heh heh , thats the spirit, just a minor hiccup in development :-)

Could the "4 o'clock" rub be because of "hydraulic??" pressure pushing the bearing across the shaft tunnel bore when the lube supply was breaking down , is the lube port feeding the bearings at 10 0'clock , if not then there might be a slight variation in concentricity , perhaps turning up a gauge tool to check alignment of bearing housing bore and piston ring bore in the diffuser housing might throw some light on things .

It'll be interesting to see how the bearing housing bores coped with the lube failure, hopefully no damage .

Yeh , take the autopsy slowly , one part at a time ............with a bit of luck she'll only need a cleanup, some new bearing bits and a rotor balance to get you back in business for next year when the snow clears :-)

More pics of the bearing bits as you pull them out please, they'll be invaluable for future reference by us guys who like "brass bush" bearings ;-)

Cheers
John

Hi John,

The lube ports are at 12 o´clock so it doesen´t make sense that the oil pressure has caused this.

The only thing alinging the comp housing and the shaft tunnel are the four bolts, no flange or lip or anything that locks it in place unfortunately. Might be worth the effort to fit a pair of lock pins through the comp housing and into the shaft tunnel to make sure nothing moves even the slightest bit between assemblies.

I will take lots of pics and measure everything, I´ll get back to you with the clearances and hopefully we can figure out of something is out of order.

Could the homemade ~5mm long comp wheel spacer mess with the rotor dynamics? I had to add it to get enough room for the thrust bearing, I know that you managed to build the engine with only standard rotary parts but I can´t understand how. The spacer is in steel and precision grided so it should be perfectly flat.

Cheers!
/Anders

[racket]

Hi Anders

OK, we should be able to rule out the oil forcing things aside.

You'll need some sort of locating devices , on the 10/98 and all my engines I use a turned rebate in the rear of the diffuser wall that the shaft tunnel fits into to provide concentricity .............LOL, the SKULD has a 115mm dia by 4 mm deep rebate for a 115mm OD shaft tunnel to fit into.

The 5mm spacer shouldn't be a problem if ground flat, on both the FM-1 and 9/94 engines I used a home made piston ring holder behind the comp wheel that displaced the comp as far forward as I could so that the flametube was as long as possible , when I made the 10/98 the comp wheel went further onto the shaft which meant a shorter flametube , but it still worked OK thankfully .

There is a slight increase in diameter of the comp shaft quill just before the comp is fully home on the quill , that increase in diameter is to positively lock the comp radially, by having the comp further forward on the quill there is a chance that the wheel won't be accurately fixed , but I don't think it could have caused your problem at the low power setting you were using ...............more likely lack of concentricity between shaft tunnel and diffuser wall.

LOL...... it was a bugger of a job getting the 10/98 engine made using the standard bits without a comp spacer , there wasn't much available space to fit the thrust bearing and the piston ring shroud , thats why I fitted the stainless piston ring shroud sleeve into the alloy diffuser wall , even on a turbocharger those parts are kinda "fragile" as the bits are rather thin and is the reason the back wall of a turbo comp housing often needs replacing after minor bearing problems .

Yep, I'll look forward to helping get things sorted :-)

Cheers
John

[turbochris]

put a little accumulator on there, just enough to keep it lubed as it spools down.

[stoffe64]

Hi anders
Im very sorry to hear about your oil pressure loss with bearing failure,those gremlins MUST stay away when testing,very sad that it happened to you but i also know that you will repair it again,keep up the good work AND your good spirit!
Cheers stephan

[wolfdragon]

Anders,

Not entirely sure if someone mentioned a possible change to your oil pump power circuit...
If you were to setup a relay to drive the pump, wired permanently ON, you could use a switch with a resistor to ground to kill the relay.

Now onto the caveats
1. The resistor would have to be a lower resistance than that of the relay coil (not hard to find just measure the coil) since current follows the path of least resistance.
2. The resistor would have to be the wire-wound power resistor type and mounted to the the frame or a heatsink to dissipate heat when you want the pump OFF.
3. You would have to find somewhere to put the resistor, which will be roughly the size of your entire thumb, in what is already going to be a very dense environment.

Just my thoughts on how to make the system a bit more fail safe.

- WolfDragon

[racket]

Hi Anders

I recently found a bit more updated technical info on the TV94 bearings at TurboMaster whilst researching for info to help with the Skuld build , heres a Link to the page www.turbomaster.info/eng/turbos/technical_data/garrett_TV94/

Also the bearings should be between 30.4597 and 30.4724 mm OD , with ID of 21.5849 to 21.5976 mm by 13.8684 mm wide.

Cheers
John

[jettoymaker]

Hi Anders,

When I was having a look at your weight summery for the bike, it twigged a question in my mind based on the weights for B1 to date and I was wondering how in the world you got the weight down so low? With the heavy battery and cast iron gearbox, you got an amazing 163.3kg.  I initially used the same method to establish weight for B1 and based on what the figures said, assumed my scales were badly out and basically weighed each component as best I could using another much smaller scale that I believed was accurate and added the sum of all parts to arrive at a weight...it appears I was patently wrong (as was the smaller scales).

I just borrowed the neighbors scale from two of my neighbors as the first one appeared to be wrong like mine: they weren't.  B1 with batteries and fluids (no fuel) turns out to be just on 170kg. and reasonable effort has gone into getting most of the components down in weight for the project. B1 is all alloy, 'including' the gearbox and like yours, has the barest minimum of operating components. I am going to be very hard pressed just to drag the dry weight down to 165kg.

Very well done on the build..now I am hanging out badly to see her flying down the track

Regards, Andrew

[gidge348]

Hi Anders

Sorry about the problem, looks like a lot of people here and landspeed.com have some very useful comments.

I think it is about time our politicians repealed....... "Murphys Law"......