Gas (Tesla) Turbine started

[marksteamnz]

The guy who built the Tesla GT was based on the North Shore of Auckland New Zealand. He gave up as the thing would not produce enough air and the hot section warped. Overall it was a disapointment compared to the tiny GT he'd built round a tubo charger off a 600cc Japanese Mini Car.
I went over and saw the tubo run and the Tesla not running.

http://www.phoenixnavigation.com/ptbc/home.htm set up in 2001 promising a complete guide to building a copy of their Tesla GT. The claims have been modified as time has gone on and it is obvious they have never had a running GT.
The Tesla people get a bit hysterical if you ask to see a working GT or steam turbine that either works or is even near as good as a conventional turbine, centifugal axial whatever. It's always because "They haven't followed the secret recipe" Yeah right, so prove it by building one, a bunch of cheap circular saw blades, a bit of CNC done, and they still are miserable performers.

Any way best of luck especailly with the hot section

[Nick]

Hi Mark,

i know where you are coming from here, Well like i said im going to finish the prototype anyway and see where i am.
Interestingly for me , having come from a Pulsejet background i was interested to see this article http://www.phoenixnavigation.com/ptbc/a ... ptbc11.htm
which is basically about using a PJ to power a Tesla turbine. In it the auther states that the Tesla is well suited to the Pj as it's more kinetically robust. He states that constant or steady state burning as in a GT combustor releases a large amount of heat and reletively little velocity (heat obviously being the main problem with his Tesla GT) whereas PJ's release a higher velocity impulse and less heat ( i now that to be true at least).
Lucky for me i have any number of small (and large) PJ's to experiment with so perhaps a concurrent project witha PJ/Tesla??? LOL if ever have that much time :?
Nick

[Bruno Ogorelec]

Nick, I think coupling a Tesla turbine to a pulsejet might be a worthwhile experiment for a number of reasons.

The first two are ideological. Both devices are suitably low tech. Both are viewed with high suspicion by engineers. They just fit together, like two orphans depending on each other in a cruel world.

But, there are more practical reasons, too.

Unlike the constant pressure combustor found in turbojets, a pulse combustor requires little or no inlet pressure to function. It does not really need a compressor of any sort. This means that it will be able to take advantage of the relatively low pressure likely to be produced by the Tesla compressor.

A conventional combustor will refuse to work under such circumstances, but a pulse combustor won't. Indeed, there are indications that a pulse combustor cannot take advantage of the really high inlet pressures. There's some kind of a law of diminishing returns at work. Most of the advantage of higher inlet pressure is realized by the first increments of the increase, with the benefit tapering off thereafter.

To me, this sounds like a good matching of characters.

Frankly, I am less sure of the turbine. Perhaps the best hybrid will be the one with a Tesla compressor and a radial turbine, rather than the other way around.

I would look into the kind of pulse combustor that does not spit back, like the Rossco thingy with inverted intake. It does not produce a reverse flow in the intake, just a pressure wave. A pressure wave should have little or no impact on the Tesla compressor, which does not depend on fluid impact for its performance. It depends on fluid viscosity. I don't think the pressure pulse will change viscosity to a notable extent.

Keep on, buddy; keep on.

[Nick]

Ive been discussing this off forum with Rossco via the wonders of MSN VOIP and am keen to pursue this, afterall i have access to pulse combustors. We were discussing the Tesla as a freepower unit, and that John's old Turbine cart is now owned by someone else who is smaller the he is, this is relevant, anyway the cart used to idle at 7lbs output with john on it it wouldnt move untill he throttled up. What is interesting is that the new owner has turned the idle down to 2lbs otherwise it run away with him even at idle.
These are very low outputs, a small-ish PJ can produce 3lbs thrust therefore if it can be put to good work via a freepower turbine, a Tesla Turbine.
Anyway time will tell i guess :-)

Cheers

Nick

[Rossco]

Ah Nick, I was talking of CC pressure! Although i am cirtanly no expert in the turbine field, or even have much experience.
There is also some major differences in gas producers between the two owners, and plumbing to the freepower.
Although, what you say works in relation to pj's as direct thrust powerplants anyway. Cameron[downunder88] himself put a little linear FWE on a scooter (wish id been there to laugh at that one), and maintained walking pace on grass... so it can be done. If you can reveal some torque out of that high speed gass stream, there is energy for the taking.
So what this GT means in relation to a freepowered PJ is anyones guess.
I know John[Racket] doesnt think much of the concept after his huge efforts!

Now, we need John, Cameron or anyone with some real numbers from a freepower GT setup to speak up here. There just may be a way of getting a theoretical idea of what were at least aiming for.

We need some good numbers on a GT, pressure, flow, velocity, etc., into a freepower. Also some idea of the freepowers efficiency and/or power output, at throttle ranges.
If we then work that back into some figures determined from pulse jets and tesla turbines (hopefully without too many of those "magic numbers") we could more clearly see where its going.

Ill speak to Cameron soon, and get some thoughts going on comparisons.
We are due to catch up again, as the first spool up of the much reworked freepower kart is, after many small, frustrating delays for him, now apon us! I just cant wait to FEEL that thing going again.
That is one amaizing, and frightful piece of equipement!
All the kart needs now is for me to track down the supercharger gearbox, to relese full potential, and heaven forbid it break a chain in the meantime.

John, all the best to you. We shall hold off till your ready mate! (Queensland Jet Meet)

OK, enough highjacking of Nicks thread.
Hopefully we can accumulate enough knowns to play with some numbers soon.

Rossco

[Nick]

As you said mate

"..................Hopefully we can accumulate enough knowns to play with some numbers soon........"

Amen to that mate!

I spent the day over at a mates house in Trowbridge, Ian who is something of an expert in alternative technologies was telling me about a plan some years ago, to use solar/steam powered turbines (Tesla Turbines no less) in the Sahara. Interesting as there was abig thing on the news about something similair today.
maybe the "big boys" really do have some specific info , there just not telling us???

Nick

[matt512s]

Hi Nick!
By a staggering coincidence, I have been kicking a similar idea around.
You, however, are way ahead of me by actually building something! I
also am planning to build a low-temp test rig to verify the concept. My
turbine differs from yours in having multiple inlet nozzles. From what I
have read, this is supposed to increase power and torque. I was also
investigating the option of powering the turbine with a multi-cylinder
Stirling engine air pump, thus making the turbine a closed cycle device
independent of combustor temperatures. Another option is tapping the
combustion chamber pressure of a pulse jet via ducts and check valves.
I hope the approach you use will be successfull!
Best Wishes;
Matt

[racketmotorman]

Hi Rossco
I'm slowly coming good :-))
What sort of number , re: freepowers on Pjs and Turbines would you like .
Camerons kart will now be flowing about 1.1 lbs/sec thru the freepower turbine , the same as when I had it , I simply "dumped" the extra mass flow from my larger turbocharger out thru the bypass jet nozzle , but the design flow for the freepower was ~ 1.1 lbs/sec with a power output of ~30 bhp at 15,000 rpm of the freepower , the freepower could be capable of spinning at up to 45,000 rpm with the gas energy/velocities available, at which point it could be producing >50 bhp .
There was ~10 psi of total pressure going into the freepower turbine, producing gas velocities of ~1200 ft/sec into the turbine and another 1200 ft/sec out of the turbine .
The design is very inefficient as there is still 1000 ft/sec of turbine exhaust velocity , this would be reduced to ~550 ft/sec if full potential rpm were used.
The simple chain reduction drive was to prove that we could get away without the complexity of gearboxes on a freepower turbine design, such as i have on the bike , and to hopefully encourage others to try using freepowers instead of very inefficient pure thrust engines with afterburners .
There could be a requirement for some changes to the scroll design if higher rpm than the designed 15,000 were used .
A gearbox would improve the torque considerably as the 15,000 rpm corresponds to ~100 kph with current chain gearing , but if one wanted 200 kph but with 3 times more rpm , that'd be a 50% improvement in torque at takeoff :-))

As for freepowers on PJs , the heat and noise from PJs just don't live up to expectations. Theres something strange going on inside them with the thrust production , I don't feel the measured thrust is produced at the exhaust outlet like a turbojet , but more up inside with a decay in useful energy as the gases get further down the exhaust section .
Perhaps someone with more of a "feel" for PJs could get one to work better than I did , but putting a correctly configured freepower onto a PJ certainly didn't cause any running difficulties with the PJ , which opens up the possibilities of a "tighter" set of gas approach and exit angles for the freepower with a greater gas deflection and torque production .

I'll have a good chat to you when I make it up your way shortly , I'll be bringing the Inlet Guide Vane set off the PJ freepower and a few other remaining bit that didn't go in the scrap bin also some more video footage on a CD for you , hopefully I'll be up before the end of the month if this back gets better and I can drive long distances again.
I was really looking forward to catching up with the Ipswitch gang last weekend , bugger :-((

Cheers
John

[Nick]

Hi John,

hope you get yourself better soon mate. Wise words none the less.
I know you tried the PJ Turbine approach so anything you can add is much appreciated

Cheers
Nick

[Nick]

Hi Nick!
By a staggering coincidence, I have been kicking a similar idea around.
You, however, are way ahead of me by actually building something! I
also am planning to build a low-temp test rig to verify the concept. My
turbine differs from yours in having multiple inlet nozzles. From what I
have read, this is supposed to increase power and torque. I was also
investigating the option of powering the turbine with a multi-cylinder
Stirling engine air pump, thus making the turbine a closed cycle device
independent of combustor temperatures. Another option is tapping the
combustion chamber pressure of a pulse jet via ducts and check valves.
I hope the approach you use will be successfull!
Best Wishes;
Matt

Hi Matt,

yep, nozzles are better but i was just being lazy on this one as i can cnc the single inlet shape easy but nozzles are more work :-)
i understand the nozzles waste less air and generate high velocity flows, i had a discussion with Rossco who pointed out a super sonic nozzle design but quite rightly noted that if you get it wrong you end up with a sonic lock and cant get any more air past it. Got to be careful i guess.
Multi-cylinder stirling engines eh?. sounds interesting but im not sure if that would be losing power to translate it it from one machine to the other?
Anyway when are you going to go for a build?
Cheers

Nick

[matt512s]

Hi Nick;
I am working on some drawings now for my engine concept, and am
proceeding from the turbine assembly outward. The idea is to make each
assembly a module that can be swapped out without junking the entire
engine. As soon as I complete the drawings (which may be a while), I
hope to post them here for comments. Unfortunately, the build of even
a mockup may have to wait until after the bathroom, the basement, the
garage and the car are squared away.
Best Wishes;
Matt

[Nick]

Hi Nick;
I am working on some drawings now for my engine concept, and am
proceeding from the turbine assembly outward. The idea is to make each
assembly a module that can be swapped out without junking the entire
engine. As soon as I complete the drawings (which may be a while), I
hope to post them here for comments. Unfortunately, the build of even
a mockup may have to wait until after the bathroom, the basement, the
garage and the car are squared away.
Best Wishes;
Matt

Oh yes the domestic upkeep stuff, such a drain on valuable development time!
Work too!
Think how much we could get done without that LOL

Never mind eh there's alway the lottery!


Anyway a small update in that i now have the shaft tunnel attached to the turbine housing so i now have to attach the compressor housing and mill the compressor discs, fix up a lube system and i can start testing!

Cheers

Nick

[larry cottrill]

As for freepowers on PJs , the heat and noise from PJs just don't live up to expectations. Theres something strange going on inside them with the thrust production , I don't feel the measured thrust is produced at the exhaust outlet like a turbojet , but more up inside with a decay in useful energy as the gases get further down the exhaust section .

John -

What you're saying here is absolutely correct, at least for a "straight tailpipe" style engine. What I was doing when I dicovered the DJ's ability to destroy Type 316 SS tubing was attempting to measure the velocity head in various parts of the tailpipe using an ordinary gauge. What I saw briefly (before the tubing started to fall apart and clogged with slag) was about 4 PSIG at the nozzle (i.e. the front end of the straight tailpipe). I had already seen that the gauge pressure is zero at the tailpipe outlet and increases nonlinearly as you move the sensing point forward in the pipe. This is, of course, a reflection of the Kadenacy "breathing" in the tailpipe.

Note that 4 PSIG over the area of the Dynajet tailpipe is almost exactly the advertised (and easily achieved) 4.25 lb thrust. The thrust reaction in a straight-tailpipe pulsejet is realized at the nozzle end of the combustion chamber - period.

I think the biggest opportunity that has been missed in trying to run a turbine from a pulsejet is in trying to take advantage of the high gas velocity (as you would with a constant-burn turbocombustor) instead of using a full-fledged augmentor and a turbine designed for efficiency at low speed and high density. I believe that approach would make a huge difference in the eventual success of the effort. I think you just need that "dilution" (which is really a huge increase in total gas momentum) to really make it work. Just my ignorant opinion, of course - however, this theory is borne out in one real-life example: the famous "SNECMA Turbine Engine", which features a built-in augmentor section as part of the tuned acoustic length.

L Cottrill

[Nick]

much much lower temps as well Larry?
Like it!
Can you sketch out what you mean?

Cheers

Nick

[Mike Spike]

site about teslas

http://my.execpc.com/~teba/