Hotstuff

[gatiep]

This surely is the hottest thing I ever made. Idles at 30,000 RPM, Full thrust set at 7 Kg at 130,000 RPM. Start on LPG, run on Kerosene at about 50 ml per minute. The casing is about the size of a Landcruiser oil filter.

[Ben from Vic.]

Gatiep,

Thats fantastic!!
Have you been making these engines for long?
Whats it cost (if you don't mind)?

Can you tell us a little about how it runs?
I'm guessing it has no turbines, it can't be a ram or scram jet, so what do you call it?

I love it.

Ben :D

[gatiep]

Ben

This is a real turbine with a compressor wheel and a turbine wheel on a shaft with angular ceramic bearings. Fuel ( kero ) is supplied through 12 x 0.5mm injectors by a stepper pump.
It is started by using either compressed air or a 12 V motor to start spinning the rotor when LPG is fed into the combustion chamber by a single injector. The gas/air mix is ignited by a model glow plug, once ignition is achieved the glow plug is switched off. Once the exhaust gas temperature ( EGT) exceeds 140C the fuel pump starts injecting kero...progressively increasing supply, until the chamber pressure ( CP) and EGT reaches a predetermined value. The LPG is then cut off. The turbine then idles at 30,000 rpm . Once fuel is increased it will increase its rpm, if the fuel keeps increasing the unit will eventually selfdestruct at who knows what rpm. The EGT during operation hovers around 480 C , both the EGT and CP is constantly monitored by the 'computer' . EGT below 140C or above 800C ,or, low or too high CP and the fuel pump shuts off. On some Rpm is also brought into the calculation.
The red hot exhaust cone is due to a wet start, to make the pic a bit more interresting. Normally the temp of the gas through the exhaust will only be about 480 C............an effective heatgun!
They are commercially manufactured nowadays throughout the world as well as in W.A. The cost in making one is a few thousand Aus $. Commercially manufactured ones will be in the region of Aus $4800 plus GST, depending on the start mode etc.
Used as powerplants for radio control aircraft. A successful turboprop model has been made here in Perth. The exhaust gas is used to drive a second turbine wheel, geared to a prop. The engine then sits back to front. I.e. if in a plane the intake is at the rear of wing, exhausting forward through the turbo turbine wheel and blowing out through sideways ducts and then rearwards round the side of the motor. A bit difficult to explain. There is no direct mechanical drive between the turbine and the prop.
Another use is in millitary drones as targets for heat seeking ground to air or air to air missiles. All I can say is that their 'heat footprint' is detectable by the missiles over a distance greater than 30 KM.
Noise.........operate only in remote areas or when all the neighbours are at work. Wear ear muffs!! It sounds just like its bigger brother in the Boeing 747. It also has that distinct delay/ sound on acceleration as well as on deceleration. If you are at a distance you will not tell the diference between the sound of the miniature and the big brother.
The whole rotor, which includes the compressor wheel, turbine wheel and the shaft must be balanced precisely......at 30,000 or 130,000 you cannot feel it running if you put your hand on the front area of the casing. Needs more exact turning than a woodturning project.

Have fun..................................keep turning

[Ben from Vic.]

Extraordinary.

Thanks for the giant reply, really interesting.
Your own jet engine.

Cool. :D

Went to the Air show once, loved it.

Ben

[coastie]

Kind of thing every mother in law should have strapped to their backs, permanently.

[Eastie]

You must have very tolerant neighbours! When working for one of our no longer operating airlines I was lucky enough to regularly see overhauls through to testing. The walls of the jet engine test bay were around 1m thick precast concrete/hollow block composite with steel air and noise baffles and a massive exhaust baffle. Just thinking about the noise they generated even through all this still sends a shiver up my spine.

The little spring gauge is a pearler – although I wouldn’t like to get too close to read the dial. What sort of retaining system do you use?

[sandman]

That's got to be one of the best gadgets I've veiwed on the web!
Love a ride!
Regards Sandman.

[gatiep]

Eastie

Underneath the motor are two 12.7 mm aluminium ribs, with the shape of the motor cut out of it and lined with very thin cork. Over the top is a stainless steel band which is pulled tight by two nuts on either side . I had it move slightly forward in the mounting a few times as the cork beds in. For safety sake I have put a wire from one mounting bolt to the other, passing in front of the glow plug. The loop where I wound the wire to pull it tight is visible. Its kind of like a safety chain on an outboard. Should the motor move forward in the mountings, the wire will snag on the glow plug body. It can then be shut down at leisure and reclamped.
In planes they are held on with two clamps, 19 mm wide x 2 mm stainless steel flat material.
This motor can develop a thrust of 13 Kg if tweaked, but as I use it as a demo motor I have kept the settings down to around 7 Kg. Saves a bit on the bearings which are $95-00 each.


Have fun.................keep turnin

[antman]

I am really impressed! Have you actually used it in anything powered that you have made? I was thinking it would make for an awsome 'jet' boat for scaring the kiddies with :D

Well done.
Anthony

[gatiep]

Anthony



My one I have only used as a test bench. There are others, same design flying in radio control planes and in millitary drones.

It would be dangerous on water, if it swallows water while it is running I surely do not want to be close by. Also the speed achievable is well in excess to what I would term safe to scare kids with.......can surely scare the pants off me.


Have fun................keep turnin.

[AlexS]

Back in the '60s the Qantas 707s used to use water injection during take off to increase thrust by getting greater mass flow through the engines. Don't know if that's still the case with 747s.

[mike boyle]

do you have any tips on how i can modify my orange gun...???

[Stuart]

I WANT ONE!

Takes me back to my Navy days- running the LM2500 jet engine on the Anzac frigate, and the Rolls Royce jet engines on test beds in England. I love jet engines :D

[antman]

I just did some random sums and 130,000rpm equates to over 2000 revs per second!!!

No wonder it scares you Gatiep:D

Anthony

[Phreddy]

Just for my two-bob's worth - that is the most awesome backyard project I've ever encountered! You're a legend!