The SpridJET - Rover Gas Turbine powered Lenham GT

[frankenhealey]

I had a BIG birthday recently and it leads one to realise that you're not going to live forever and if you're going to do another multi-year vehicle build it should be special.

What to do?

So I made a list.

1) It must be from the 1950's
2) It must be interesting
3) It's got to be smaller than the Green Goddess based Transporter I've just finished.
4) It should be raceable
5) It should be a challenge to build
6) It must be as noisy as f3ck
7) It must upset classic car 'old farts'
8) Dan Dare (Buck Rogers for our US friends) would have driven it.

So the power plant arrived in early December






It's a Lucas Mk105 ex-RAF Vulcan/Nimrod air starter




Specification: Power Output 100-150Bhp : Compressor RPM 64,000 : Power Turbine RPM 47,000

Sadly no reduction gearbox and all electro/mechanical.

I made a cardboard sizing template so I didn't need to to lug the turbine in and out of the 1971 MG Midget roller we acquired.

The roller was in remarkably good shape due to copious underseal and the good old A series automatic anti-corrosion system of oil leaks.




The team aren't taking this too seriously






Cardboard turbine fits rather well



This is what we hope it will look like 






Sadly if we're going to run it as a Landspeed car then this is the record holder with much lower drag and powered by a Bell Jet Ranger Turbine with a minimum of double the horsepower

[pitciblackscotland]

Hi Ian,
Very nice,yes cardboard templates is what i use and sometimes drawings as well.

Cheers,
Mark.

[gidge348]

Hi Ian

Must agree I think CAD (cardboard aided design) is very handy design tool.

Cheers
Ian

[racket]

Mmmmm, some nice bits of kit there , an interesting build coming up :-)

Cheers
John

[Deleted]

Hi.

don't know if it would be of any help, but I have most of the manuals for the rover 2s150...

What do you plan to use as a reduction box, are you removing the air compressor and if so, will that affect the engine governor

[frankenhealey]

Hi Andy,

I have some manuals but anything gladly accepted. We don't know what will happen when the air compressor is removed but I'll be building a test bench for it and will be looking at various control options if we have a governor problem. I'll be making my own reduction box and then bridge the gap with a high power belt drive.

Here's one I did earlier





Cheers,

Ian

[frankenhealey]

Now the dumbass questions start

Here we have the the gear-driven 'services' end of the turbine, everything except the emulsion air pump which is electrically powered on the other end.





This is the gear drive diagram





Now I presume I can gain some horsepower by using electric fuel and oil pumps as the compressor turbine will be using less energy so more is left for the free power turbine or is that completely wrong? Or worse still hardly worth doing? Electric would allow me to keep the oil flowing at full pressure during shutdown and I could more easily control fuel using a PWM controller to avoid overspeeds. Does this make sense please? 

Cheers,

Ian

[jetric]

Hi Ian,
A word of warning about these engines, do not run the engine with the compressor removed i.e. no load on the freepower turbine as there is no governor on the freepower the compressor is sized so that it puts enough load on the freepower turbine to keep the rpm's in check, The gas producer side of the engine has got a mechanical governor inside the fuel pump that is set to full throttle rpm's so the engine will just start then run flat out, the fuel system is mechanical apart from the solenoid fuel shut off and the gas producer can be throttled down to idle speed by putting a tee into one of the fuel lines ( I will have to upload a picture of wich one for you )and fitting a needle valve as the throttle then returning the bleed back to tank.
The engine in the video is one that i got running for a friend this guy has got another 15 of these engines plus a unit full of every single spare part N.O.S. for these engines check out 'jet engine trader' on the web.
Rover did make a version of this engine with a reduction gearbox ( 6000rpm output ) and it had a governor on the freepower it was used as an apu engine and sat above a RR Dart turboprop engine to drive the engines acessory gearbox to power the air conditioning and generator whilst the aircraft was on the ground there is a video of my one i used to own on my youtube page 'jetric32'
Any questions just ask.
Rich.

[jetric]

Hi Ian,
Its not worth removing the oil pump and fuel pump as they will only be consuming about one to two HP maximum together, removing them will just make the gas producer run very slightly cooler on egt's because you will still be limited by the maximum safe rpm's of the gas producer, anyway if it did make a difference it would only be a couple of HP max.
Rich.

[frankenhealey]

Hi Rich,

I bought the unit from Harry at Jet Engine Traders. He's been feeding me with some info but he's busy, busy, busy. Would a disc brake, on the freepower turbine that stalls the shaft for short periods such as testing etc, be OK?

Thanks for your advice it's much appreciated.

Cheers,

Ian

[jetric]

Hi Ian,
Whilst you are getting used to the engine i.e. first test run i would just leave the freepower compressor on but DO NOT block off the inlet or outlet to the compressor this is a safe way to run the engine whilst you are sorting out the throttle controls, oil tank, fuel system etc, once you have got a throttle control sorted and you can idle the gas producer then it would be ok to remove the freepower compressor and put a disc brake on the freepower. these engines produce about 140hp flat out, if the disc brake started to slip at these power settings it wouldnt take long for the disc to be glowing red hot,
are you based in the UK or US?
Rich.

[frankenhealey]

Hi Rich,

I'm down in Deepest Daaaarset, UK. I'll leave the compressor on for setup and testing as you advise. Love your video on Youtube and the noise these things make.

You don't know of any Rovers with the reduction gearbox for sale by any chance?

This is a great forum.

Cheers,

Ian

[jetric]

Hi Ian,
Nope dont know of any of the reduction gearbox ones for sale now, I sold my one to harry in part ex for a RR Gnome with full paperwork that i wanted off him, At that point harry had two of the reduction gearbox rovers; his own one ( that i got running for him ) and my one i had just sold to him. I dont know if he has sold both of them now but i know they will not be cheap due to how rare they are now, I was going to put my one in the back of an auto toyota MR2 i even bought the car just didnt have the time, You will get more acceleration off the line putting the freepower through an auto box ( of course with the tourque converter removed ).
Are you keeping the original 'A' series engine in the car? if not then why not put the turbine engine up front, you could charge passengers for a ride in a turbine car then!

Rich.

[frankenhealey]

Rich,

The entire plan was to build this as a Landspeed car because of this bit of information.





I'm a Healey race guy and I wanted an excuse to do something interesting and simultaneously upset the Healey club so here we are. The car won't have the A series in it and will be powered entirely by the turbine. Acceleration is not that important as the 'short' course at Bonneville is 3 miles and if I could get onto the 'long' course it's 7 miles. A Lenham bodied Spridget with 80 bhp did 131mph so I'm hoping to break 160+ with a few more aero tweaks. The turbine is not a great fit in the engine bay with inlet and exhaust routing problems so the decision was to plonk it in the passenger side suitably firewalled and run the exhaust out of the back. 

Quick question on ignitors. Do I have to have a genuine one or can one be made up from automotive components?

Cheers,

Ian

[jetric]

Hi Ian,
Both bulk heads can be removed from the engine also the intake duct can be removed aswell because the engine has got an intake filter screen fitted to the engine inside the intake duct that is not fixed to the duct( you have to attack the intake duct with tin snips to remove it the easy way or you could do it the proper way but you have to remove all of the accessories and plumbing off the front to remove it forward ). A word of warning if you are going to put the engine at the side of you in the cockpit please fit a burst sheild of 1/4 inch thick plate between you and the engine because if anything on your final drive line fails the freepower turbine will instantly overspeed and possably burst with enough energy to cut you in half!!!
With regards to the ignitors they are surface discharge and wont work with a high tension ignition coil i.e. car igniton coil/gas fire coil you have to use a cracker box with them ( this is the common name for them because the unit works by charging up a large capacitor then discharging the capacitor across the ignitor plug with a loud crack noise ) harry has got a few of these units for sale from aircraft engines, if he has got none left i could make you a unit up that uses modern electronics with a microwave capacitor for about the same cost ( a word of warning with regards to cracker boxes only power them up when they are connected to the ignitor plug because if you accidently touch the ignitor lead end whilst the capacitor is charged it will give you an instant heart attack!!! )
Rich.