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Oh.....so.....just those 12 or 15 things then.?Only by designing a new accessory housing.
That does not do much apart from house and/or drive the starter, generator, vac pump, fuel pump, camshafts, magnetos, gun synchronizers, fuel pump, oil pump, coolant pump, hydraulic pump, cuno filter, etc, etc.
In short, everything except the prop and the prop governor.
Regards the Allison in the P-51
1 - Could the Merlin 2-Stage have been mated to the Allison without much fanfare.?
2 - If that WAS possible, would the P-51 have the same gas mileage with the Allison as the Merlin.
3 - Could Allison have kept up with the demand for Allison motors, in a P-51 from 1944 onward.?
Alison production peaked in 1943. It was the only major US engine to actually decline in 1944 going from 21,604 to 20,191 with numbers dropping month by month. In the last 1/2 of the year it was basically producing at 1/2 capacity. In contrast Packard was increasing production rapidly and further more Continental was scheduled to start producing Merlins and Oldsmobile was being brought in to produce components for Merlins. Packard produced 15,084 engines in 1943 and 22,969 in 1944.Regards the Allison in the P-51
Could the Merlin 2-Stage have been mated to the Allison without much fanfare.?
If that WAS possible, would the P-51 have the same gas mileage with the Allison as the Merlin.
Could Allison have kept up with the demand for Allison motors, in a P-51 from 1944 onward.?
Thank You
Yeah, i was think "Economy" along the lines of bomber escort to Berlin........stuff like that.It could be done, the question would be whether it could have been got into production in numbers to make a difference, and if it wasnt better than the Merlin why do it? The P-82 twin Mustang first flew as the war was coming to an end.
"Economy" depends on many things, I have read that the RAF found the the Mustang MkI to be more economical in low altitude low speed conditions because the Allisson engine ran more smoothly at low revs.
The P-82 was intended to be Merlin powered but after VJ day Packard lost the licence. The Allison contract was cancelled shortly after VE day. Allison actually had to set up a new production line.It could be done, the question would be whether it could have been got into production in numbers to make a difference, and if it wasnt better than the Merlin why do it? The P-82 twin Mustang first flew as the war was coming to an end.
"Economy" depends on many things, I have read that the RAF found the the Mustang MkI to be more economical in low altitude low speed conditions because the Allisson engine ran more smoothly at low revs.
I know, but I was replying to the OP. If the Allisson had a RR supercharger tagged on it would also be in part a licensed product. One of the reasons I posted "Economy" depends on many things", is because er economy depends on many things. The P-51 was 30MPH faster than a Spitfire in top speed but was faster than a Spitfire at all engine settings, so went further on the same fuel/hour, the P-51B?c D was more economical because of its airframe and same (as you say) in a Mosquito. Additionally, the Allisson may have run smoother at low revs, low altitude, but that may be because it was optimised for low altitude use anyway, my knowledge of superchargers doesnt stretch that far. but generally there is no free lunch with engines, the single stage Merlin was better at higher altitudes so maybe low speed "lumpiness" was the price paid, it frequently is with tuned engines.The P-82 was intended to be Merlin powered but after VJ day Packard lost the licence. The Allison contract was cancelled shortly after VE day. Allison actually had to set up a new production line.
The Allison engine did not perform as well as the Merlin and had significant problems. According to Ray Wagner in Mustang Designer, Edgar Schmued hated the Allison.
People for some reason beat on the Merlin as being some sort of gas hog, quoting SFC as if that were the whole story whereas in practice the Merlin accomplishments speak for themselves. Merlin powered Mosquitoes and Mustangs flew some of the longest missions of the war in their category of aircraft. In fact the world record for non stop flight set in 1947 was by a Merlin powered P-82B.
The Merlin had the most efficient cooling system of any water cooled engine. They worked very hard before WWII to reduce the drag of their cooling system and it paid off. Read Chapter VIII of Development of Aircraft Engines by Robert Schlaifer
Another wonderful reference is Hucknall - The Rolls-Royce Flight Test Establishment by David Birch, published by the Rolls-Royce Heritage Trust in 2017.They worked very hard before WWII to reduce the drag of their cooling system and it paid off. Read Chapter VIII of Development of Aircraft Engines by Robert Schlaifer
And that also bolts directly to the Accessory housing assemblyCarb on the Merlin was updraft, carb on the Allison was downdraft...
1 - It was mated for test purposes, and it seems to have worked. At least per 'Vee's for victory' book.
2 - Yes, if not better, since V-1710 have had the greater compression ratio.
Love to hear of the significant problems.The Allison engine did not perform as well as the Merlin and had significant problems.
On what page does he make that statement?According to Ray Wagner in Mustang Designer, Edgar Schmued hated the Allison
The Allison was the preferred engine by those doing low level Rhubarb type missions because it provided greater range through better fuel economy and was more robust, being better able to endure abuse, so good in fact that they removed the boost control in order to increase manifold pressure. When the Merlin production line started the USAAC operating in Africa put forward a proposal (have a copy) to keep the Allison powered version in production because of its superior qualities in the low level role. The Merlins forte was its high altitude capability. The better economy of the Allison was due to its ability to run at very low RPM that the Merlin was unable to match.
People tend to forget that the Mustang was originally designed as an Army Co-operation aircraft ie low level operations, for which the Allison was the perfect choice.
Hi EmuLove to hear of the significant problems.
The Allison was the preferred engine by those doing low level Rhubarb type missions because it provided greater range through better fuel economy and was more robust, being better able to endure abuse, so good in fact that they removed the boost control in order to increase manifold pressure. When the Merlin production line started the USAAC operating in Africa put forward a proposal (have a copy) to keep the Allison powered version in production because of its superior qualities in the low level role. The Merlins forte was its high altitude capability. The better economy of the Allison was due to its ability to run at very low RPM that the Merlin was unable to match.
On what page does he make that statement?
People tend to forget that the Mustang was originally designed as an Army Co-operation aircraft ie low level operations, for which the Allison was the perfect choice.
The RAF pilots flying the Mustangs developed a technique for their operations that required longer range. They had a set of engine/boost/rpm settings that allowed a lower rpm and boost setting that gave a low fuel consumption but relatively "fast" speed cruise (around 240 to 250 mph). They would use that for the over water crossing to a point close to the enemy coast. They then went to a higher rpm and boost setting that gave a moderate fuel consumption (around 270mph) , accellerated up to a higher speed, then went to a higher rpm and boost for the crossing of the enemy coast (around 300-320mph) and penetration into the occupied area beyond the main coastal defence belts. They then went back to a rpm and boost setting that gave them a good higher speed cruise around 270mph, from which they could accelerate rapidly if intercepted or needed extra speed to engage a target of opportunity, but one that still gave good fuel consumption. The setting they used had been determined by extensive test and practice flying over the UK and gave a good balance between speed/performance and fuel economy, plus avoiding engine setting that led to things like spark plug fouling or excessive oil cooling. They also had engine managment practices they used during periods of extended 'cruising' to vary engine setting to reduce engine issues. Exit from enemy occupied territory and return to base in the UK was a reverse set of engine setting to those used on the approach.The Allison Mustangs had lower drag, due to being less powerful and requiring less cooling. This played a role in the performance of the Mustang I/II vs the III/IV at low level, including fuel economy.
I'm not sure that running very low rpm was a wise thing in a combat zone.
It really wasn't. Certainly no more than the P-40 or P-39 were designed as "Army Co-operation" aircraft.
And if it was the case, it would have been unlikely that the Mustang would have changed from the 8.8:1 supercharger gear to the 9.6:1, which was aimed at better altitude performance.