Turboshaft Racecar?

[racket]

Hi

If we have a known temp rise of 182 C degrees as in the earlier example, then I multiply by 0.24 ( Cp air), then divide by Cp of the gases at known design temp , say 0.28 for our sorta temps , so a 156 C drop through the turb stage to "balance" the comp requirements .

I then multiply T I T by the turb stage efficiency , so 1173 K X 0.78 = 915 .

Divide the 915 into the temp drop of 156 =0.17049 .

Subtract 1 = -0.8295.

Divide into minus 1 = 1.2055

Then yx it to 4.0322 ( this is 1 divided by 0.248) this then is the pressure ratio required = 2.12.

If we have a 3.5 PR into the stage then theres a 1.65 PR out or 9.6 psi of total pressure in the jetpipe/interstage duct.

My apologies if my numbers jump around a bit , I'm taking snippets from different lots of previous calcs that have differing T I Ts and Cps etc etc , I'd need to do more accurate "numbers" from known and guesstimated parameters.

Cheers
John

[rcman50166]

No worries. I've been busy so I have not been able to poke around with the calculator lately. But I do have a mockup PT106 in the mail for solid modeling. Precision Turbo and Engine will lend out housings with a security deposit. It does not come with a compressor and turbine wheel, however. But it will have enough dimensions to fully model the engine in Solidworks. Things are starting to look interesting.

[racket]

I'll be looking forward to seeing what comes :-)

[rcman50166]

Got something in the mail!



Flipping through it and boy there is a ton to do.

[racket]

LOL..................thats a start ;-)

Its in SI units which makes it a bit hard for me to understand having got use to the Imperial units in my earlier Edition copies.

A bit of light Christmas reading for you

Cheers
John

[rcman50166]

Someone got an early Christmas present.



Precision Turbo and Engine PT106 with 1.5 A/R turbine.



I will be modeling the whole thing in solidworks but if any of you have questions about any of the specific dimensions I could pull them quicker. I do not have any of the internals.

[racket]

Hi

Hole sizes in and out for just about everything , also the bearing/centre housing arrangement .

If the "hole in the front " is 106 mm dia , the "hole out the back" should be 112 mm , it'd be interesting to see what sort of "nozzle" is inside the turb scroll , so a pic looking into the entrance would be appreciated to get an idea about the flow area within the scroll, a 1.5A/R housing should be reasonably "fat" but not a doughnut shape.

Cheers
John

[rcman50166]

Compressor intake:



Compressor outlet:



Turbine intake:





Turbine outlet:



Turbine outlet is 116mm.

The best I can do for the exhaust gas channels. Right where the inlet opens to the scroll is about 0.75"






I'll get to the oil/bearing bits later. I have to take the turbo apart to get at it. If I make a ton of headway on the model, I'll just publish the blueprint.

[rcman50166]

Progress is slow but definite. I only need to model the compressor and turbine housing. Two or three more days, at the rate I'm going. Hopefully everyone is having a restful holiday season!

[rcman50166]

Turbine Housing done. Not surprisingly, modeling a revolved surface with changing diameter and cross section is difficult in Solidworks.



It's not an exact copy, but all of the mounting surfaces are identical relative to each other, which is all that really matters. If I were doing flow simulation, I might consider doing it over.

Just leaves the compressor housing.

[rcman50166]

Let's see if these forums can do imbedded gifs.



Now that's done, I can move forward with design. I'm going to try and design two. The first will have 2 turbochargers, the second will have 4. This will allow for a little wiggle when I find a racing class that will allow the engine.

John, here are the major dimensions of the oiling bits you wanted:

[Johansson]

I hope you will find a class that accepts your choice of engine. When my landspeed bike was in the planning stage I contacted the Swedish dragracing authorities to hear if my future bike could compete in one of the index classes, the rules for them state that choice of engine is unlimited so I figured that it would be ok.

No no no no, was the answer I got. Anything without pistons is apparently very dangerous, so that was when I decided to go land racing instead of drag racing.

The problem isn´t really the rules but the ones interpreting them, anything unusual is viewed with extreme skepticism and twice so with a "jet engine". Ignorant safety guys think it will blow up instantly or break down in a way that hinders the race somehow, at least that is the case around here.

Luckily we have persuaded the landspeed community here to accept our home made jets, but it took a handful of years before they looked relaxed when we pushed our contraptions to the starting line...

Cheers!
/Anders

[smithy1]

Jan 3, 2017 0:22:18 GMT -5 Johansson said:

I hope you will find a class that accepts your choice of engine. When my landspeed bike was in the planning stage I contacted the Swedish dragracing authorities to hear if my future bike could compete in one of the index classes, the rules for them state that choice of engine is unlimited so I figured that it would be ok.

No no no no, was the answer I got. Anything without pistons is apparently very dangerous, so that was when I decided to go land racing instead of drag racing.

The problem isn´t really the rules but the ones interpreting them, anything unusual is viewed with extreme skepticism and twice so with a "jet engine". Ignorant safety guys think it will blow up instantly or break down in a way that hinders the race somehow, at least that is the case around here.

Luckily we have persuaded the landspeed community here to accept our home made jets, but it took a handful of years before they looked relaxed when we pushed our contraptions to the starting line...

Cheers!
/Anders

Yep Anders...we have the same issues here in Aus....the main problem is the fact that most of these drag racing people don't understand turbines, I try to explain to them that my thrust engine essentially only has one moving part and is very safe compared to a normal piston engine...no rods, pistons, cams, valves etc trying to get out....falls on deaf ears every time. This is why I now do a lot of car shows and similar events....very seldom do I get to run the beast down a track unfortunately.

Cheers,
Smithy.  

[racket]

Hi Smithy

The really silly part is those same GT6041 turbos are being abused to death on "infernal combustion engines" without them worrying one little bit , they should ban them for that use as well .

The 6041 is probably the safest turbo around as far as containment goes , perhaps after you've done a thousand shows without drama they might think more kindly about giving you a run ;-)

Cheers
John

[smithy1]

Jan 3, 2017 15:29:36 GMT -5 racket said:

Hi Smithy

The really silly part is those same GT6041 turbos are being abused to death on "infernal combustion engines" without them worrying one little bit , they should ban them for that use as well .

The 6041 is probably the safest turbo around as far as containment goes , perhaps after you've done a thousand shows without drama they might think more kindly about giving you a run ;-)

Cheers
John

Hmmmm, a thousand shows eh?? Let me see, I do ~20 shows a year and have been doing it for ~2 or 3....should only take me another 47 or 48 years ..LOL..!

Cheers,
Smithy.