And a piccy for you Eric

 Does it look like a modern colour piccy of a mossie under construction

A couple of thoughts. The unlimited racers in the USA feature a lot of P-51 Mustangs. They were powered by Packard Merlins and they are still being sercived and restored. I suspect that there are quite a few available there.

 One or two of those racers have been fitted with Griffons  which are very close to the Merlin being based on that engine but a lot more powerful. These were used in Shackletons so there could be a few of those around.

Pete

I believe you are correct, there ar a lot of unused Merlin enigines out there. The Fantasy of Flight seem to have crates of them. I understand that some hydroplanes still use them as well as the Unlimited pylon racers.

From what I have read and been told, both Packard and Ford made a better Merlin than RR ever did, in that the engine was Production Engineered, Fits were more consistant, power was slightly higher and they cost less.

I am sure that RR are exceptional units today, but in the 30s, it was RR that claimed they were the best car in the world, not others singing their praise.

Erfolg  

Erfolg there is a well know and verified story that when RR first sent the blueprints over to Packard they were returned with a statement that Packard could not work to the tolerances provided.

RR were chuffed thinking Packard couldn't work to such tight tolerances as themselves... only to then be a little embarrassed when Packard informed them they needed the tolerances tightened up. There are merlins and merlins, the Packard version being dubbed the 'high altitude merlin' with different bearing materiasl and modified supercharger and substantially improved high altitude performance.

The merlin also saw use after the war in airliners such as the Avro Tudor so I guess we could well have a situation where the number of engines still available to this day out numbers the airframes requiring them.

OOPS!

The Griffon was NOT based on the Merlin but on the "R" engine used in the Schneider Trophy sea planes built before the Merlin was even designed. It was bigger, 36 litres as apposed to 27 but not actually that much more powerful as it was not quite so highly stressed. It was the high octane fuel (from America) first 100, then 120 and finally 140 that boosted the power. Packard Merlins were built to the American standard of limits and fits (better?) and thus the parts are not directly interchangeable with the RR types. The main claim was that the Packard versions did not leak as much oil!

I thought that I had read that the Packard Merlins were better than the RR ones but didn't like to say so because I was not sure.

 I am a bit puzzled by the statement that the Griffon was not much more powerful than the Merlin. The Shacks used them with contra rotating props, each of which were about the same size as the average Merlin prop. I can't quote H.P. figures though. I do know that  Merlins have been replaced by Griffons in unlimited racers for the extra power so the external dimensions can't be that much larger.

If the Griffon was based on the "R" engine, what was the Merlin based on?

hi

    heres the power output figures as posted on wikipedia the merlin first followed by the griffon

 MERLIN 61Power output:
Note: 100 Octane fuel, +12 lb boost.

• 1,280 hp (955 kW) at 3,000 rpm at take-off.
• 1,565 hp (1,170 kW) at 3,000 rpm at 12,250 ft (3,740 m) (MS gear)
• 1,390 hp (1,035 kW) at 3,000 rpm at 23,500 ft (7,170 m) (FS gear)[14]

GRIFFON Power output:

• 2,035 hp (1,520 kW) at 7,000 ft (2,135 m)
• 1,820 hp (1,360 kW) at 21,000 ft (6,400 m)

there is not much to chose between the engines HP/lb but the Griffon being 36 litres as opposed to the merlins 27litres is more powerful than the highest spec merlin

there's your figures

nasa

Hi Peter

For some time It could be said that RR really only made two sizes of  V12 aero engine - big & bigger! The smaller (21 litres) was for fighters, the bigger (36 litres) for bombers. Each was developed more or less  together for more power but the fighter engine usually took the lead. What pushed RR ahead of the rest was taking the big bomber engine, the Buzzard, and really sooping it up into the racing R engine. This would run for 1 hour (just) at 2000 hp on a special fuel mix. This supercharging engine technology was then applied to the small engine, the Kestrel, to produce the Peregrine (885hp) but it was close to its development limit & as aircraft designers were already looking for 1000hp plus the Merlin was designed from scatch at 27 litres. It eventually reached 2070hp. The late mark Griffons in the Shackleton produced 2340hp.

Remember these hp figures are "rated" power, typically 100 hrs or more but if you don't mind knocking them to bits much more is possible for short bursts. The Reno racers achieve over 4000.

To try and be fair to RR, at the begining of the Second World War, RR probably were not a very large organisation.

They lacked the experience of Packard, Ford or Mercedes Benz of making thousands of products at low prices, yet requiring a degree of precision to allow interchangability of spares etc. They were a little like bespoke tailors or McClaren Racing Cars.

I am sure that the orgainisation today knows a lot about production engineering as well developing an excellent design concept.

I just feel it was a pity that Metro Vics were told to stand aside by the UK Goverment, to allow RR to become the preffered/established UK supplier. As the MV F20 was a better engine (as a concept and engineered) than RR engines at that time. Being axial flow aginst RR centrifugal.

Erfolg

Yes, the friend and I were only  saying that the Americans had production lines down to a fine art by that time. Also RR were having to produce engines very fast under difficult conditions.

After all, the American engine of the day was the Allison which was not very good. Allison engined Mustangs were poor until they fitted the Merlin. But then America really preferred the radial engine for some reason.

I can also tell you that in WW II someone (I forget who, some group commander) was converting their P-38 Lightning to Merlins but the powers that be ordered him to stop for political reasons. This is not generally known. I was told this by the late Roger Freeman when I asked him why they had never done that.

To give credit to the Americans and other designers, their devices often work very well when used as intended.

I guess tha Allison was designed for relatively low altitude work. However I get the impression that the fighting powers sought ever greater altitudes to fight at, as they sought to evade the opposition. However sometimes it was necessary to fight at low level as in Ground support/attack mode. Requiring differing engine characteristics for maximum efficiency.

Reputations are often made or lost by circumstances. I am thinking of the Typhoon which would have gone down in history as a failure if used in its intended roll, fighting at medium altitudes, as Sydney Camm and his designers choose a poor wing section. Or the Whirlwind which lacked a two stage supercharger for high altitude fighting (not withstanding the engine situation).

Erfolg

Hold on a tic - who says the Allison was bad!

Yes the early variants were low altitude rated but in its element it was as quite as powerful as the Merlin and reckoned to be a touch more robust. Yes the superb Mustang airframe benefitted from the Merlin but that was because what was needed was a high altitude fighter.  The P38 Lighning with its turbo supercharged Allisons was very fast at altitude and good for nearly 40000 feet. Mechanical supercharged Merlins would have been of no real advantage. Later when the Alison did get the two stage 3 speed super charger, an intercooler and high octane fuel it got up to 2240 hp (P51H) a bit more than the best Merlin and on just about the same capacity (1710 cu in against 1650 for the Packard Merlin). Of course both these engines were pretty small when compared to the huge P&W radials.

Eric. Surely it was only the Griffon that went round the other way and this caused some problems on late mark Spitfires to pilots used to Merlins.

I may be wrong, but I'm certain the Packard Merlin ran the other way around, causing problems with screwing off the side of the strip if the pilot applied the 'wrong' rudder!

Erfolg, the main reason for the ever-increasing combat start-altitude was simple - height could be converted to speed, and air/air combat was really hit and run, diving out of the sun, more than out and out combat. Two or three circles, and everybody would be so scattered it became fuel and time wasting chasing any longer. Don't forget, disregarding the films, these fighters only carried enough ammo for about six seconds of firing anyway. Plus the bombers, the main target, were being forced up higher for more or less the same reason, to get above the AA fire, and to give 'protection' from the fighters, which took a long time to climb to any useful height.

This has taken us a long way from the origin of the thread! 

Just to continue Gemma's sub-thread, three photos of the Duxford Mossie under restoration. The photos were taken through the crew's access hatch.

Eric

My main point is, it is unfair to say this was intrinsically good and that was not very good. This seems to be the case with the Merlin, it was a fine engine, who ever made it, but it was not streets ahead of all others.

I feel for a lot of designers who are often blamed for all the short comings in a product/system. In most cases you are working against a specification and functional requirements produced by a client, the client never gets the spec wrong, it is the designer who lacked long term vision.

I totally agree with the contributors who have pointed out that piston engine performance was directly affected by the octane rating of fuels and not just the genius of the designers.

I do stand by my view that some highly praised aircraft, were failures when compared with there intended role, but are seen as great sucesses because a role was found for them, which allowed them to appear better than otherwise.

Erfolg