RR Pennine dimensions

[Nick Sumner]

Does anyone have any dimensions for the RR Pennine engine, ie LXBXH - I have the cylinder dimensions.

Thanks

[Nick Sumner]

I contacted the Rolls-Royce Heritage Trust and received a reply from Mr Ian Craighead whom I have to thank for furnishing me with the following information.

"The Pennine had a capacity of 45.73 litres (2791 cu. ins.). The overall length (over propeller shaft and starter) was 106 ins. Its height was 37.50 ins and width 39 ins. The engine dry weight was 2850 lbs. It developed 2740 bhp at 3500 rpm at sea-level maximum take-off conditions and up to 2800 bhp under combat settings. It differed from the Exe by having an epicyclic reduction gear which meant that the propeller shaft was in line with the crankshaft. It never progressed beyond the initial development phase as the advent of the jet engine eclipsed its potential."

[Wuzak]

I contacted the Rolls-Royce Heritage Trust and received a reply from Mr Ian Craighead whom I have to thank for furnishing me with the following information.

"The Pennine had a capacity of 45.73 litres (2791 cu. ins.). The overall length (over propeller shaft and starter) was 106 ins. Its height was 37.50 ins and width 39 ins. The engine dry weight was 2850 lbs. It developed 2740 bhp at 3500 rpm at sea-level maximum take-off conditions and up to 2800 bhp under combat settings. It differed from the Exe by having an epicyclic reduction gear which meant that the propeller shaft was in line with the crankshaft. It never progressed beyond the initial development phase as the advent of the jet engine eclipsed its potential."

Thanks for that Nick.

Apart from the length, that is quite a compact engine. Smaller frontal area than a Sabre. Would fit inside a 55in cowling - similar in size to a big radial - R-2800, R-3350, Ceantaurus.

Also, the performance sounds impressive. Similar capacity to an R-2800 but matching the maximum horsepower of the best of those radials early in development. I think slightly heavier than an R-2800, but not by much (probably accounted for by the dual rotation propellor reduction gearing and fan installation.

One wonders why RR designed the Eagle 22 as an H-24 when a liquid cooled version of the Pennine would have been more compact and lighter.

[Nick Sumner]

Interesting to note that the 5 inch stroke at 3500 rpm gives a piston speed of 14.8 m/s. 3800 rpm would give 16m/s and 4000 17m/s.

To hark back to an earlier converstaion about the RR Eagle 22 - it has been critiscised for its weight of 3900lbs but its PWR would still be about 1.0, which ain't too bad. I wonder if the weight reflected sturdy construction, perhaps with a view to pushing boost and rpm as far as possible?

[Groggy]

Hi Nic,

There was a reference in a Book about a Fairey Aircraft written by Harrison that gave the expected output as about 3,500 hp. I think it gave an altitude; must look for it on the next visit to the library, May have been for the Firefly?

Wonderful to get those measurements, its very compact good for a transport or bomber?

[Wuzak]

From my recollection the 2800hp was developed with relatively low boost (as compared with the Merlin, anyway). So no doubt that could have been upped a bit as development proceeded, and the max rpm raised as RR engineers gained confidence in the strength of their design.

As regards the Eagle22, I still think it was overly heavy. The Pennine and the Eagle were roughly the same capacity, but the Pennine was roughly 1100lbs lighter. And even though the Pennine was long at 106in it was still 30-odd inches shorter than the Eagle! Maybe the difference has something to do with the supercharger system (Pennine, IIRC, had a single stage supercharger).

Some may suggest that it is the liquid cooling system's fault for the weight. But I am not sure that this is really the case.

[Nick Sumner]

More information from Mr. Craighead;

"+12psi boost at Max take-off and combat settings. Yes, it was a single stage, two speed supercharger."

[Groggy]

Hi Folks

I agree with you about the Eagle and as for the liquid cooled types I thought radiators etc were always extra added on to the comparative engine weight?

The Pennine t/o power output given to Fairey to work out Firefly performance was 3,480 bhp,

From the 3,000 bhp output given for a developed Centaurus version at the same time must have been about 1943 or 1944 at the latest?

Thanks for sharing the dimensions etc, have not seen these published before.

[Wuzak]

Hi Folks

I agree with you about the Eagle and as for the liquid cooled types I thought radiators etc were always extra added on to the comparative engine weight?

The Pennine t/o power output given to Fairey to work out Firefly performance was 3,480 bhp,

From the 3,000 bhp output given for a developed Centaurus version at the same time must have been about 1943 or 1944 at the latest?

Thanks for sharing the dimensions etc, have not seen these published before.


No, I think the weights specified in liquid cooled engine installations are only for the engine itself - not including radiators.

Similarly for turbocharged engines, the turbos were not included in the engine's weight, unless it was expressed as an installed weight.

3480hp would be a magnificent achievement for a Pennine. Matches the power of the Eagle22 for much the same capacity, and much less weight, and matches or betters most versions of the R-4360 for power whilst being much lighter and similar in capacity to the R-2800. If it could make those numbers then it would have been arguably the finest air-cooled aero engine.

In comparison to the Centaurus the Pennine was slightly heavier, but also slightly more powerful (at 2800hp) - and probably more potential due to its shorter stroke and therefore higher rpm.

Groggy, where did you find the 3480hp number from?

Wondering if that was done with rpm or boost?

[Groggy]

Hi Wuzak,
A book at the local library one of the few good books left there.
Fairey Firefly by W.Harrison,
Rated for T/O so would be at sea level.?

The Comparison was between four possible versions,
The Pennine, 3,480 hp at t/o no other details given but will check again
Super Centaurus, 3,000 hp This had better altitude performance
Centaurus, ? will check again
Griffon, ? will check again

[Wuzak]

Quckly scanning through the variants of the R-4360 in Graham White's book of the Wasp Major, it looks like the most powerful production version of the R-4360 was about 3800hp at take-off. IIRC that was around 3600-3700lb, but would have been run in conjunction with turbochargers, which are 300-400lbs each, at least. Most appeared to be in the 3000-3500hp range, and in the 3400-3600lb range.

Of course there is a wide variety of accessories and configurations which make a large difference to the dimensions. The lightest R-4360 was about 3100-3200lbs, but that was a direct drive - ie no reduction gearing on the engine. The heaviest versions were tipping the scales at just over 4000lbs.

The most powerful versions of the R-4360 appeared to be the experimental VDT engines - where all boost requirements were met with turbochargers, and no engine stage supercharger was fitted. A couple of them were rated to 4300hp, whilst one version looked to be rated at 4800hp. None of these engines entered production, particularly because no suitable control method had been built for the VDT.

Most R-4360s looked to be in the 95-105in long range. Some versions were as much as 130in long, whilst ones fitted with extension shafts or remote supercharger were quite a bit longer, but give no meaningful comparison.

The minimum diameter for he R-4360 was 52.5in, but this varied according to the exhaust system fitted, most being no more than 55in. Some were as much as 66in, though.

[Groggy]

Hi Folks ,
Try this site, what do you think to the Wyvern+Eagle?

[Red Admiral]

Hi Folks ,
Try this site, what do you think to the Wyvern+Eagle?

Some photos of the only surviving Wyvern at FAA Yeovil. It never flew, being delivered to Boscombe Down for static tests. There is a short video of another example flying and an interview with one of the test pilots. It was surprisingly maneuverable for the size, but poor acceleration compared to fighters because it was so much heavier. The Eagle engine was quite strange, the revs didn't change much when the throttle was opened, just more fuel added and the pitch of the blades changed to give more thrust. The pilot also lamented the fact that the Eagle wasn't split into two separate engines for extra reliability.

The Eagle used quite a lot of the technology developed for the Crecy. Sleeve valves, dribble fuel injection... I have a very good report on the Crecy with lots of details and pictures if anyone wants a copy then pm me with their email. Its about 40 pages and has some really interesting points. I'll throw in another report about gas turbine development at RAE as well (with more pictures, numbers and graphs)

http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/WestlandWyvernHunter.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/WestlandWyvern.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/WyvernEagleinstallation.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/WyvernFlaps.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/WyvernRadiator.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/Wyvernfrontal.jpg
http://i25.photobucket.com/albums/c84/AviationImages/FAA%20Museum/Wyvernotherfrontal.jpg

[Wuzak]

So the Wyvern-Eagle had a semi circular radiator under the nose and wing mounted radiators as well?

[Wuzak]

pilot also lamented the fact that the Eagle wasn't split into two separate engines for extra reliability.


So, a double Merlin, which had been mooted mid war, might have been the go?

Bearing in mind that the double Merlin was projected to be more powerful than the Eagle, and yet lighter.

[Red Admiral]

So the Wyvern-Eagle had a semi circular radiator under the nose and wing mounted radiators as well?

I seem to remember that the oil cooler was in the nose and the wing radiators were for glycol coolant.

[Groggy]

Hi Folks,

Returning to the Pennine was there a pre war / 2ndwar Miles Airliner with eight Exe or Pennine engines?

[Wuzak]

The Exe, the predecessor to the Pennine, was developed in the '30s, but was abandoned at the outbreak of war. According to A.A.Rubbra, Rolls-Royce Piston Aero Engines - a designer remembers, Rolls Royce Heritage Trust, RR built and tested a liquid cooled version of the Exe.

Some parallel work was done on a liquid-cooled version of the Exe engine. An experimental 4-cylinder 'star' unit was constructed, using steel cylinders with fabricated steel water jackets. These jackets proved to be very prone to cracking, so the cylinders were redesigned in cast aluminium. A main engine [ie an X-24 - wuzak] was produced and tested, but as with the air-cooled engine work was discontinued on the outbreak of war.

In this chapter he mentions that the Exe was rated at 1150hp at take-off. I wonder what the Exe-LC was capable of?

I am also guessing that the liquid-cooled version also used separate cylinders - makes a simple conversion from the Exe.

[Wuzak]

Another revelation from Mr Rubbra:

Although the EagleIX was nominally rated at 360hp, there was little or no margin in the rating to allow for small discrepancies between engines.

It was common practice for tester to inject a syringe full of Castrol R oil into the carburettor intakes during the taking of a power curve when the engine was slightly short of power and the AID representative was not looking. This practice usually ensured a pound or two extra on teh Froude brake scale pan, by reducing the effect of piston friction.

;):eek: