Tornado Reheat unit.

[suerog]

Hi guys. As a designer who worked for Dowty Fuel Systems, I did a lot of work on the RB199 Reheat control unit. I was recently able to buy one of these units to prepare for display.What I could really use is a document detailing the assembly/disassembly of the unit. Does anyone know how I might be able to get one please?

[NutLoose]

I did a a very very brief time in the bay in Germany over 40 years ago, the RAF engine bay tended to overhaul as modules, and those damaged modules would go back to the manufacturers .

i would suggest your first port of call would be the Rolls Royce Historical branch at Derby.

[Vendee]

As Nutty suggests, these units were only stripped down by the manufacturer. I think occasionally on the Sqn or engine bay test bed, we might swap out the T1 actuator or the turndown actuator but I don't think we did any more than that. I'm sure I've got the RHFCU internal schematic diagram in my RB199 course notes which I could probably scan in and send to you if you wanted. It is an impressive schematic but not a strip/assembly guide. Good luck with your project.

[suerog]

Thanks NutLoose, I'll give them a try.

[suerog]

Just as I thought really. Dowty Fuel Systems disappeared in the Dowty sell-outs years ago, and I'm finding it difficult to contact whoever has picked up responsibility for these units. A circuit diagram would be a good start as it should show the way the various components are linked mechanically inside the main bodies. It would be great if you could send me a copy.

[Vendee]

Originally Posted by suerog

Just as I thought really. Dowty Fuel Systems disappeared in the Dowty sell-outs years ago, and I'm finding it difficult to contact whoever has picked up responsibility for these units. A circuit diagram would be a good start as it should show the way the various components are linked mechanically inside the main bodies. It would be great if you could send me a copy.

Private message sent.

[Buster15]

Originally Posted by suerog

Hi guys. As a designer who worked for Dowty Fuel Systems, I did a lot of work on the RB199 Reheat control unit. I was recently able to buy one of these units to prepare for display.What I could really use is a document detailing the assembly/disassembly of the unit. Does anyone know how I might be able to get one please?

I worked on the RB199 for quite some time. The RHFCU was quite a beast being a complex hydro-mechanical unit.

You will most probably know all about it. But the main components were:
The fuel inlet valve.
The vapour core pump, which was always rotating and a centrifugal pump design.
The TT1 actuator which featured a 3D cam to vary the fuel flow split between the 3 reheat streams - core or gutter, bypass or colander and primary.
The turndown actuator which electronically increased or decreased reheat fuel flow.
Hot shot fuel to the hot shot injector in the combustion chamber.

Because of the relatively high bypass configuration of the engine and having a massive reheat boost of close to 90%, there was also a separate Purge, Prime Shut-off Valve - PPSOV.

When the pilot selected reheat, the RHFCU flow went from 0 to Max and back to 0 in 0.25 second. This was to prime the 3 reheat manifolds.

This happened while the Nozzle Air Motor drove the nozzle to its initial opening stage.
The nozzle area always led fuel flow.

At the point that the nozzle reached its demanded position, AJ, the RHFCU then went to the scheduled fuel flow split between the 3 reheat streams.

The biggest problem in service was the TTI actuator bearing failure and the vapour core pump bearing failure.

Unfortunately, the hot shot injector fuel supply was underneath the RHFCU, and hot shot injector blockage due to carbon build up became a significant maintenance problem. Not a Dowty part.
And a number of cleaning techniques were tried to not have to remove the RHFCU.

Best of luck.

[suerog]

Thanks Paul(?) A schematic might be helpful. My email address is [email protected].

[howiehowie93]

Originally Posted by Buster15

And a number of cleaning techniques were tried to not have to remove the RHFCU.

I worked Tonka First Line for a while (ten years OMG !!!)
The Dry FCU had to come off the replace the Hot Shot so at every change the Hot Shot was replaced as a precaution "whada you mean you didn't replace the HotSho !!!!!! - K@#B"

Then there was the squirt a syringe full of Avtur to disolve the carbon build up method or the Landrover speedo cable dipped in OM15 (hydraulic oil the same as Redex apparently) and pushed up to be spun and umpteen thousand RPM with a Windy Drill.
Never much success.
I sugested LIX (?) as used by the Phatoom Phleet but I don't think there was any left by then, all gone like AVPIN.

In the end I understand a baffle device was developed by RR and was fitted to the tube that had a convienient connection and the Engine run up and reverse pressure flow cleaned it out.

H

[NutLoose]

Lix was used on the VC10.

[Buster15]

Originally Posted by howiehowie93

I worked Tonka First Line for a while (ten years OMG !!!)
The Dry FCU had to come off the replace the Hot Shot so at every change the Hot Shot was replaced as a precaution "whada you mean you didn't replace the HotSho !!!!!! - K@#B"

Then there was the squirt a syringe full of Avtur to disolve the carbon build up method or the Landrover speedo cable dipped in OM15 (hydraulic oil the same as Redex apparently) and pushed up to be spun and umpteen thousand RPM with a Windy Drill.
Never much success.
I sugested LIX (?) as used by the Phatoom Phleet but I don't think there was any left by then, all gone like AVPIN.

In the end I understand a baffle device was developed by RR and was fitted to the tube that had a convienient connection and the Engine run up and reverse pressure flow cleaned it out.

H

Exactly that. The Land Rover Speedo cable was not as effective as hoped, because in the main, all it did was to push the carbon further into the tube.

The reverse purge was the eventual solution.

Bet you miss those days ?