|
Post by Johansson on Nov 6, 2011 1:45:16 GMT -5
I meant to ask you, and I have sifted thru all 38 pages once, tho may have missed it. What turbo are your internals from? Or can you tell me what diameter is your inducer/turbine? what is the ratio between the surface area of your compressor to your turbine surface area? cheers. The rotary parts are from a Garrett TV94 turbo. Don´t know their exact diameters though.
|
|
|
Post by Johansson on Nov 6, 2011 1:50:07 GMT -5
I noticed with your biuld, the difference in gas generator size to power take off turbine size is bigger than any other biuld Ive seen. Will this be a problem? or will you just size the gearing to siut? Im assuming you will be putting in nice stator guide vanes to make the most of the energy in the gas flow? According to John´s calculations the 3d stage axial turbine wheel from an Allison 250 C20 is the best suited wheel that was possible to source for me, it is a bit on the large size but close enough.
|
|
|
Post by racket on Nov 6, 2011 3:03:15 GMT -5
Hi Stimps
Comp 98mm inducer 141 mm exducer with a 10mm tip height , turb , 129mm inducer with a 19mm tip height and a 106mm exducer .
Thats a 4th stage C20 wheel for the freepower , it will need a "tight" NGV angle , but its a very good wheel to use , we're also using the same for our bike .
Don't know what the local equivelent of the ceramic spray is , .......but shouldn't be too hard to find :-)
Good to hear you've got a bit more time for your project .
Cheers John
Cheers John
|
|
|
Post by Johansson on Nov 6, 2011 7:45:42 GMT -5
Damn, 4th it is.
|
|
|
Post by racket on Nov 6, 2011 16:34:20 GMT -5
Hi Anders
Heh heh , you need the big one , not the whimpy 3rd stage wheel , thats what I used with my "little" TV84 gas producer ;-)
Cheers John
|
|
stimps
Member
Joined: August 2010
Posts: 18
|
Post by stimps on Nov 7, 2011 4:32:32 GMT -5
Well at least being that big, it should have plenty of torque!
|
|
|
Post by Johansson on Nov 7, 2011 15:45:50 GMT -5
I´ve finished all wiring now so hopefully I should have time to give her a spin the weekend after the one coming up. I fitted a pneumatic solenoid valve to the propane preheat line so I won´t be able to forget to turn the propane off after the engine has started, the solenoid valve is connected to the ignition push-button so I will have to keep it pushed in during the preheating. The oil pressure switch was connected to a switching relay to make it cut the current to the fuel pump if the oil pressure disappears. Finally I fitted a cola bottle to the purge hose so I won´t get oil all over the floor. Cheers!
|
|
|
Post by racket on Nov 7, 2011 21:48:14 GMT -5
Hi stimps
With 150 hp at ~32,000 rpm it should be producing ~25 ft lbs of torque at the turb shaft , this will be roughly doubled at stall due to the characteristics of freepower turbines , so ~50 ft lbs , multiply that by ~6:1 thru the redux and we're looking at ~300 ft lbs at the output shaft at stall , with another say 2.5 : 1 redux to the bikes rear wheel theres ~750 ft lbs to do the accelerating .
Cheers John
|
|
|
Post by racket on Nov 7, 2011 21:49:12 GMT -5
Hi Anders
Lookin' better all the time :-)
Cheers John
|
|
|
Post by Johansson on Nov 8, 2011 1:01:26 GMT -5
(...) theres ~750 ft lbs to do the accelerating . 1000Nm is insanely much, how much does it drop off once the bike starts rolling? I would say it looks messier and messier for every day, but thanks anyway! ;D
|
|
|
Post by racket on Nov 8, 2011 3:44:50 GMT -5
Hi Anders
Its a fairly linear drop back to ~half that max stall torque at max rpm as we start "trading torque for horsepower" , thats not the correct description but you know what I mean :-)
With say 375 ft lbs of torque at the rear wheel , if that wheel is 2 feet in diameter , 1 foot radius , then you'll have 375 lbs of "thrust" at top speed to counteract the bikes drag .
At stall rpm with the gas producer at full power , you'd have 750 lbs of "thrust" with that 2 feet dia rear wheel.
Cheers John
|
|
|
Post by Johansson on Nov 8, 2011 11:58:01 GMT -5
The first road test will most likely be interesting in other words.
|
|
|
Post by racket on Nov 8, 2011 14:28:57 GMT -5
Hi Anders
Turbine bikes are very easy to ride , no clutch or gears to worry about , just give her some throttle and away you go ..............simple , if you want a fast takeoff just hold the brakes on, windup the gas producer to full bore and let the brakes off ......................heh heh ,you'll probably find it a little "boring" ..............sorta like driving a car with an automatic gearbox .
But it will be fun :-)
Cheers John
|
|
Deleted
Joined: January 1970
Posts: 0
|
Post by Deleted on Nov 8, 2011 18:35:25 GMT -5
hi.... all looking good, be nice to see more running. thought you mite want to have look at this site racingbatteries.co.uk/ mite be able to save some wieght and space.... look for ward to seeing new video www.diygt.org
|
|
stimps
Member
Joined: August 2010
Posts: 18
|
Post by stimps on Nov 8, 2011 21:59:43 GMT -5
Im a great fan of doing things light, as weight robs horsepower. Ive been collecting lithium ion regargable batteries from laptops, and am considering trying a battery pack made from twenty cells or so. Just a thought! Would have to be better than a lead acid, but of course the starting system my force you to do otherwise.
750ft/lbs. DANG.
|
|