Rolls Royce BMW T312 Tornado's APU variable throttle

[jmb18]

Hi everybody.!

I've a T312 and i'm searching some infos to have a variable throttle and also build an ECU/FADEC

If you've this or any others infos on the T312, do you want share with me, pls.?

[luc]

Hi ,did you found some info for it ? I am interested as well in this engine

[roddix]

Hello, I TOO HAVE A T312 and need a bit of assistance with the ignition wiring and a simple start system.
Any assistance will be well received
rod
EMAIL
[e-mail]

[turbotom]

Most important before you attempt to start these units: Put a pressure regulating valve in the hydraulic pressure output port that was supposed to operate the clutch of the SPS in the Tornado. This is the innermost port with the smallest cross section. If you just duct this port back into the oil tank, there won't be enough oil pressure to properly lubricate the engine's bearings / gear box. Some spring-loaded ball valve with a drop of 3 bar across should do. I'm in the process of making an electric range extender based on one of these engines and will post more information once I've got actual results. These engines are quite delicate and for reasonable repair / maintenance work, way too complex. They are really a nightmare to work on. Special tools needed for virtually everything and then there's the thorium-doped magnesium alloy that the two bearing seat housings are made of, which makes the whole unit mildly radioactive (and no sign or indication for this to be found anywhere). It's probably not severely dangerous as long as none of the material is machined/ground and the dust inhaled or ingested. Anyway, be careful with these units.

By the way, in order to throttle one of these engines, I would use a (needle) bleed valve to vent some of the CDP from the acceleration control port of the FCU. This way, it's not a "real" governor but it's a half-way clean approach of speed control without having to mess with the fuel system directly.

Cheers,
Thomas

[stoffe64]

Any progress with this engine?,i am really Interested in this engine, any information greatly appreciated!

[turbotom]

I've got to revise my previous recommendation a little after a complete teardown of a damaged unit and some hands-on experience of another machine: The original lube system of the T312 consists of two stacked pressure regulators, the first one adjusted to the high pressure to operate the multi-disc clutch in the SPS gearbox, the second one (fed by the oil bypassed through the first one)to provide the lube pressure. This means, if there isn't any spillage though the first regulator, the engine won't get lubrication. So, in order to run the engine without any modification, you've got to block the high pressure oil port completely and operate the oil pump relieve valve during engine startup.

A more elegant way to do without the 2.5+kW mechanical oil pump drive power is to modify the valve block by removing the high pressure regulating piston, spring and spring seat plate. The valve insert is very hard to unscrew, you've got to make a solid, well fitting tool for that and heat the valve block to soften the gaskets that bind the insert to the valve block body.



If you run the engine with the fuel pressure regulator valve installed, it's recommendable to have a fuel pressurizing pump feeding the engine (0.5 ... 1 bar is sufficient). The oil intake port is equipped with a fuel-pressure operated valve that only opens after the fuel pump is producing sufficient pressure. It keeps the intake completely shut while the engine isn't spinning, thus the oil system will stay primed and immediately produce pressure once the valve opens. This valve needs some space in the oil intake port which means that you must not slide in the engine-supplied oil port adapter home completely. I made the mistake to think that the partition wall on the port adapters is meant to slide flush with the oil port body. I couldn't be more wrong! Both the oil intake adapter as well as the oil return adapter need to have a clearance of at least 10...15mm between the partition wall and the oil port body for the system to operate properly. Otherwise, the return port will be obstructed and the suction port valve movement will be limited, actually closing the suction line. I end up machining new adapters for the installation I'm working on.



And just for information: The output voltage of the RPM pickup on the T312 is rather low (compared to a Solar T62 for example). At 100% RPM, you will see in the ballpark of 8Vpp at 6.267kHz with 20...50% amplitude modulation at 133Hz into a high impedance input. When starting to crank the engine, the output voltage is just a few hundred millivolts.

I hope this information may be of some help to other enthusiasts

Cheers,
Thomas

[stoffe64]

Hello Thomas!
Thanks for your reply, very interesting this,do you have any photos of the oil pressure ports?...a Photo say qite much Cheers/stephan

[turbotom]

Aug 26, 2019 1:06:34 GMT -5 stoffe64 said:

Hello Thomas!
Thanks for your reply, very interesting this,do you have any photos of the oil pressure ports?...a Photo say qite much Cheers/stephan

Of course you are right, so here we go:

First thing first, the oil suction valve insert in the closed configuration.



Once the engine is being cranked and the main fuel bypass solenoid valve (NO) is closed, fuel pressure builds up and acts against the end surface of the farmost bellows. The suction line valve will eventually open. The valve plate moves a total of approx. 8mm.



Since the valve seat, installed in the oil interface block, is approximately flush with the land in the suction port, and the far end of the valve plate will extend to round about 10mm above the land surface, the oil suction adapter needs to be installed with round about 15mm clearance from the "fully home" position. Otherwise, the valve will just be forced against the tapered area of the suction adapter and more or less effectively block the oil flow.



Moreover, the oil return adapter blocks the return line if slided in completely.



If retracted by about 15mm, everything's "nice and dandy", but that information is not to be found in any of the available documents on the engine (as well as the fact that both the compressor bearing casing and the "inner" gearbox casing are made of a magnesium-thorium alloy and emit quite some radiation).



There's ample space for the O-ring seals to do there job, even with the adapter inserts in the retracted position.



I guess that clarifies the stiuation with the lube system of the T312 pretty well. Actually, I consider this machine a nice little engine, but for a serious application where one may want to service the engine to keep track of its condition or to repair it, it's way too complex. I considered designing a prop gearbox for it but it's not worth the effort. One-off conversions like the shown range extender for electric flight might be feasible, especially if spare engine(s) are available, but other conversions will quickly turn down the same road as the Jet Exec, Helicycle or Ultrasport families with the difficulty to find even half-way usable Solar engines while the prices sky-rocket.

As an overly-complex toy to have some fun and convert fuel to noise, this machine doesn't leave much to wish for, though

Cheers,
Thomas

[stoffe64]

Thank you Thomas,you are a great teacher and with such german precision, even i understood!! Thank you Again!!
Cheers/stephan

[stoffe64]

Which of the oil ports are the high pressure port?,that one should be blocked completely..right?
The largest port is oil Into engine?
The third port is the return to oil tank, is it here it should be a valve to raise the pressure? ,correct?
Cheers/stephan

[turbotom]

Stephan -
the easiest way to distinguish between the T312's oil connectors is by the diameter:

- the smallest one is the high pressure output that in the original application operated the multi-disc clutch (cap it off when not in use)
- the intermediate one is the oil return port (you may want to run it through an oil cooler back to the oil tank)
- the oil suction line is the biggest port (obviously)

Don't install any valve in-line with the oil return port. The return oil may contain an ample amount of air so your oil tank my need a vent. I'm not sure if it's possible to utilize the centrifugal oil/air separator of the engine for that purpose. If there's access to an air balance line on the engine, it should be feasible. Otherwise, I'ld just put a vent cap on the oil tank and possibly live with some oil loss due to the mist escaping there...

Cheers,
Thomas

[stoffe64]

Thanks for your reply Thomas, greatly appreciated my friend!
Cheers/stephan

[stoffe64]

What is holding these connections in place?,when it comes oil pressure they Will be forced out?,since they should be retracted 15mm i assume that they can slide out fully?....voila!!....oil leakage and No oil pressure!
Cheers/stephan

[jetric]

Oct 2, 2019 23:49:58 GMT -5 stoffe64 said:

What is holding these connections in place?,when it comes oil pressure they Will be forced out?,since they should be retracted 15mm i assume that they can slide out fully?....voila!!....oil leakage and No oil pressure!
Cheers/stephan

  Hi Stephan,
   Be very careful with these T312`s regarding oil pressure, as the engine will only last for three seconds without oil pressure before it seizes/blows up,
  Check out this video of a successful run of my engine with my design of throttle control;




  This throttle conversion is now being used in a helicopter that has a T312 installed in it made by FAMA helicopters of Italy.


   Richard S.

[stoffe64]

Hello Richard!
Thanks for your reply, i have seen that video several times and all the others too regarding the T312.
Cheers/Stephan