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Maybe, but sticking the condenser for an A/C unit in front of an engine radiator has been standard practice in automobiles for many years, with no ill effects...and I don't think that one qualifies for the "apples-to-oranges" argument.I would think you would want to give the intercooler it's own supply of air. either using already heated air or trying to feed heated air to the oil cooler doesn't sound like a good idea. besides, you might want to be able to control the cooling of each device independantly.
You know they learned that from Cleaveland, right?Shortround6 said:Because of Allison 'modular' aproach to engine building the front drive, whether reduction gear or extension shaft, could be bolted to any block...
You know, I found something the other day that stated that the -45 engine also used a hydraulic clutch for the aux. stage.
It even stated its reference source was the same as yours - Vee's for Victory.
I can't seem to find it now, but if I ever do, I'll post the link for you.
As for the picture, thanks.
When you blow it up to like 400%, you'll see its actually fairly well detailed.
That pic, plus the one I found here (note the 3rd plane down from the top), both seem to show a little room behind the engine. I wonder if that space couldn't occupy at least some of the second stage (I'm assuming the extra length is coming from the addtional SC and its plumbing).
This would mean that the nose wouldn't stick out quite so far and adding length to the rear of the fuesalage, as Clay had mentined earlier, would be a less drastic affair.
I wonder how bad it would be to push the cockpit back, maybe 3"-4"?
Would it be that different to fly/taxi?
I'm just thinking about the combined weight of the H=S prop and the -45 engine.
Elvis
...forgot to address this part...
Maybe, but sticking the condenser for an A/C unit in front of an engine radiator has been standard practice in automobiles for many years, with no ill effects...and I don't think that one qualifies for the "apples-to-oranges" argument.
...Of course, if you went "IA" (intercoolded and aftercooled) with that setup, then each unit could be smaller and maybe you could fit them to each side of the oil cooler.
This would require a small change to the cowling, of course.
...and there's no law that says you can't place them elsewhere, either.
Also, on "independant controls" for SC radiators and oil cooling:
You're saying less SC cooling at SL and more at higher altitudes?
That seems to be a bit much for the pilot to worry about, while in combat.
I'd think if you're going to cool the charge, just cool it, regardless of altitude..
Hey, that was quite interesting to read.apparently I was in error. The -45 and -47 engines used both types of drives depending on when in their development we are talking about or exactly which serial number engine
From "Vee's for Victory" pages 345-346.
"In it's intial form, on the V-1710-45(F7), the drive for the Auxiliary Stage was an all mechanical affair with a friction clutch for vibration damping. 4
What was unique with the developed drive was the method for insulating the supercharger from torsional vibrations inherant in a direct drive from the crankshaft. In 1942 Allison fitted a small hydraulic clutch, much like that used in automatic automobile transmissions, to drive the Auxiliary Stage. This provided another significant benefit in that it could be operated to allow a significant amount of "slip" and thereby providean infinately variable control of the speed of the Auxiliary Stage impellor. The unit speed was as controllable as that of a turbosupercharger. The benefit being that the engine throttle could be efficiently maintained wide open so that manifold pressure and power were controlled by the speed of the Axiliary Stage. This minimized the amount of compression heating in the induction systemwhile at the same time reducing the power required to drive the Auxiliary Stage. Quite a neat set up."
From page 269:
"F-7R: As the V-1710-45, this 1940 project was the first V-1710 to use the new Auxiliary Stage Supercharger and thereby become a mechanically driven two-stage V-1710. Contract W535-ac-16146, dated December 2,1940, was issued for one experimental engine. Change No. 1 was issued in July 1942 to cover redesigning to provide a larger Auxiliary Stage Supercharger (12-3/16 inch diameter impellor replaced the earlier 9 1/2 inch unit) driven by a hydraulic coupling instead of the original friction clutch. The delivery date was changed from September 1941 to February 1943. Obviously the effort was considerably behind schedule at this point. A second contract, W535-ac-22957 was issued in December 1941 to purchase an experimental engine with aftercooler for the Classified Project No. MX-69, which was the airplane that became the Cutiss XP-60. This version of the two stage Allison never achieved flight status."
And from page 256:
" E-9: This was the first two-stage V-1710 to reach flight status. It incorporated the Allison designed and mechanically driven Auxiliary Stage Supercharger. Development of the two-stage V-1710 components began in 1940 and endured a long development cycle, during which a number of different supercharger ratios, both for the engine stage and the Aux Stage, were tested.
Develpment work on the auxilary stage for this engine dates from 1938, and seven of these engines were purchased on development cointract W535-ac-19859 dated June 1941. This followed seven months after the pioneering contract for the two-stage V-1710-F7R. One engine was for development, with two each for installation in the XP-39E and XP-63 airplanes, with two engines held as spares. The engine went through considerable evolution during it's development, in fact, revisions to Allison specification No.137 were issued through "G", all of which used 7;48 engine stage supercharger gears. As early as February 1942 the engine was running in the Allison ltitude Chamber.27 Without the intercooler the engine weighed 1,525lbs.28
In February 1942 development testing of a hydraulic drive for the auxiliary stage supercharger was begun. In July 1942 it was decided to replace the friction clutch in the drive with the automatic hydraulic coupling on both the F-7R and the E-9.................As early as September 1940 the Allison Specification No. 137 was revised as 137-A to reflect the incorperation of an intercooler. 31 The device never went into the production models of the engines...............Aftercooler development for this engine was terminated in December 1943 in veiw of the poor characteristics of the cooler provided by the Harrison Radiator Division of General Motors and the large amount of mechanical trouble with the set up.33"
there are several more pages of text, charts and tables concerning these engines in the book, Why he says 7 engines in the text and list 3+ in the production table for the -47 I have no Idea. Numbers scattered through the text are the numbers of the footnotes.
I am not saying that you would have to extend the nose the entire amount of the extra length of the egine but moving back a whole lot might not be easy. for instance the engine mount had sidesway braces that went from the rear of the side tubes to a common mounting point in the middle of the firewall about half way in hight between the upper and lower mounting points. 5 mounting points total.
The 2 stage engines were put into P-40 airframes, this has been mentioned before. See the P-40Q.
It just wasn't going to be done simply or quickly or without disrupting production.
The big prop might not be nessassary unless you get the engine a lot closer to 1600-1800hp than the 1150-1325hp the -45-47 were originally rated for.
You're welcome, but why do I have this odd feeling that...Thank you for your comments.
Shortround6 said:As far as the propellors go you might want to check your HP figures.
Which version of the Allison has been the main point of discussion since Clay resurrected this thread with the H-S prop idea ?Shortround6 said:There are all kinds of nominal HP figures floating around for Merlin engines. WER for a -7 Merlin was 1720HP in low gear at 18.25lbs of boost (67in ). using 150 octane fuel they could get even more. If you are talking about an 1942-43 Allison engine then you are rarely going to be reaching anywhere near that power.
What has to be remembered in looking at Allison was that up until 1940 it was a very small company. Before 1940 they had only delivered 67 V-1710s and then had to deliver hundreds of engines in 1940 followed by thousands in 1941 and 1942. even with their modular aprouch they were working on the P-40 engines, the p-39 engines, P-38 turboed engines, several other proects and the V-3420 project( side by side V1710s driving a common prop) Even with help from General Motors there was only so far their engineers could stretch.
try looking at the dates on the Curtiss P-53 and P-60 projects to see when Cutiss and the Army started thinking about improving the P-40
.
Which version of the Allison has been the main point of discussion since Clay resurrected this thread with the H-S prop idea ?
.In case you're not following, I was referring to the -45 version, when I quoted the 1325HP figure.
It maybe and it might not be, but the real point is that by the time the -7 Merlin showed up most military engines had a WER rating that was at least several hundred HP above the take off rating. Propellors were being fitted to get the most from this WER rating. The AAF was a little late getting into the WER game and didn't allow over boosting officially until sometime in 1942, WHile it might (or was) done at squadron level it means the AAF wasn't buying propellors fo HP ratings the engines weren't supposed to reach..As for the P-M HP rating, I believe that figure is take-off power for the -7 engine, used in the P-51D.
While I've seen a numvber of figures bantered about over the years, this one seems to keep coming up, from various sources.
No arguement with that, but I will point out that the Original Merlin in the Spitfire was rated at 1030hp at 16500ft but only 880hp for take off when using 87 octane fuel. So is it an 880HP engine or a 1030HP engine? and which rating at which altitude do you think the designed the propellor for?.The 1325HP figure for the -45 is also take-off power (granted, it was never actually installed in an airplane. Still, that is how the figure is listed and thus, how I am using it).
.Yes, I'm sure the staff at Allison were VERY busy during those years, as was everyone else, but then....this is the "What if " thread.
I still don't think you recognize that an American fighter capable of flying top cover would be an incredible asset in 1942. You keep saying that low altitude performance would have suffered, and I have no problem with that. If the P-40 could fight effectively at 20-25k feet, we could use the P-39 at low altitude just like the Russians did (to great effect).THe point is that I don't believe a "magic" propellor will really do anything for a 1942 Allison engine.
Oh, I am following , but could somebody pease explain to me why this magic propellor would increase the performance of the P-40 so much over just using a -73 Allison of 1325HP for takeoff as used in the P-40K? Granted it does tend to top out at around 12,000ft instead of the 21,000ft of the -45.
It maybe and it might not be, but the real point is that by the time the -7 Merlin showed up most military engines had a WER rating that was at least several hundred HP above the take off rating. Propellors were being fitted to get the most from this WER rating. The AAF was a little late getting into the WER game and didn't allow over boosting officially until sometime in 1942, WHile it might (or was) done at squadron level it means the AAF wasn't buying propellors fo HP ratings the engines weren't supposed to reach.
Propellors are also designed for the altititude at which they are going to work. Propellors for high altitude work needed more blade area for the same HP than a low altitude propellor would have. Using high altitude porpellors at low altitude might actually reduce performance. larger, heavier propellor has more drag and needs more power to rotate it in the thicker low altitude air.
By the way, the Allisons those trick propellors were going to go on in the P-38K were turbocharged engines rated at not just 1425HP for take off but 1425HP military power at 27,000ft and a WER of 1600hp. A new version of the Turbo (B-14) model was expected to give a service ceiling of 46,000ft. BOth 3 bladed 12' 6" and 4 bladed 12' 0" propellors were considered with the 4 blade version being able to utilze the power better especially as the altittude went up. These engines also used a 2;36 reduction gear to keep prop speed down.
Please note the -45 was good for 1150hp at 21,000ft.
No arguement with that, but I will point out that the Original Merlin in the Spitfire was rated at 1030hp at 16500ft but only 880hp for take off when using 87 octane fuel. So is it an 880HP engine or a 1030HP engine? and which rating at which altitude do you think the designed the propellor for?
True, it is what if. But there is the fantasy what if ( what if we had P-80s at Pearl Harbor)
and there is the "we could have done so much better if the generals in charge at the time weren't so stupid" what if's. The first is fun if a bit nonsense, the second sort of requires proving the generals actually were stupid. Or that the suggested "modifications" could actually be done in the suggested time line.
Or if the suggested modifications would actually work.
My self, I am partial to a MK II Westland Whirlwind as a what if but sticking with modified Peregrine engines and not trying to go to Merlins.
I still don't think you recognize that an American fighter capable of flying top cover would be an incredible asset in 1942..
You keep saying that low altitude performance would have suffered, and I have no problem with that. If the P-40 could fight effectively at 20-25k feet, we could use the P-39 at low altitude just like the Russians did (to great effect).
It would not have out-turned the 109 in Africa or out climbed it, even with improved climb, but it could have out-dived it and it was still a far more durable aircraft. Flying in sufficient numbers and using good tactics (stay out of low speed turns, dive-and-zoom) the P-40 could have given excellent account of itself against the best fighters of 1942 at all altitudes.
There Russian aces that flew I-16s, There might even have been 1 or 2 that flew I-153sThe P-39 was great flying low altitude missions. The Russians loved it and there were several Russian Aces in it.
Some of the modifications propesed would have hurt performance at low altitude and yet NOT given you the hoped for performance at high altitude. Not a very good trade-off in my opinion. Lets see, pull the Merlin -1 from the P-40 F that gives 1120hp at 18,500ft and replace it with a two stage Allison of about the same weight the gives 1150hp at 21,000ft. Yeah, that extra 2,500ft of altitude is going to make all the difference when fighting 109Fs and Gs. except the Allison is longer which requires a longer nose and longer tail to balance things (both weight wise and stability wise) and this is going to add how much weight?
Are you still planning on using the "magic" propellor? how much more that does that weigh?
of course you can still pull two of the guns to lighten it up but that tends to give up one of the P-40s historical advantages. And while the P-39 might have worked against the Germasn down low It probaly wouldn't have done much better against the Japanese that it did. Of course the Russians did tend to change a good number of their P-39s didn't they? like take the wing guns out.
wikipedia said:In June 1940, Henry Ford had offered to manufacture 1,000 aircraft a day if the Government would let him do it his way, and during a discussion with Secretary of the Treasury Henry Morgenthau Jr. regarding what the Ford company might produce, Ford's son Edsel tentatively agreed to make 6,000 Rolls-Royce liquid-cooled engines for Great Britain and 3,000 for the U.S.[2] However, at the beginning of July Henry Ford stated that he would manufacture only for Defense, not for Britain, and the entire deal was declared off. Members of the Defense Advisory Commission subsequently began negotiations with other manufacturers in an effort to place the $130,000,000 Rolls-Royce order,[2] and Packard Motor Car Company was eventually chosen because the parent British company was impressed by its attention to high-quality engineering. Agreement was reached in September 1940, and the first Packard-built engine, designated V-1650-1, ran in August 1941.[3]
Ford building R-2800s explains why the R-2800 never seemed to be in short supply.Part of the deal with Packard was that the US was to get 1/3 of Packards production.
The order books for Allsion in Oct of 1940 show 4315 engines on ordered under French and British contracts with the Air Corps having another 1050 on order.
Orders at Packard were for 6,000 engines for the British and 3,000 for US.
By Sept of 1940 the US goverment had given over 14 million to Ford to build a New plant to make R-2800s. Starting from a plot of bare ground Ford deliverd the first production engine in about a year and finished 1941 by delivering 264 engines. Ford went on to build 6403 R-2800s in 1942.
Packard managed to deliver 49 Merlins in 1941 but put out 7251 Merlins in 1942.
First P-40F was delivered in Jan of 1942.
I really doubt having ford build Merlins would have gotton that many more engines much sooner and since Ford built over 57,000 R-2800s by the end of the war I think they did their bit. By the way production peaked in July 1944 1944 at 186 engine per day.
US actually wound up with more Merlins than it knew what to do with which is one reason why the Merlin P-38 idea was brought up three times.
Could a better P-40 have been made, Probably, but not in time to much good in 1942 and by the end of 1942 the P-40 had had it's day and was being used as a cheap fighter to supply our allies with under lend lease.
THe point is that I don't believe a "magic" propellor will really do anything for a 1942 Allison engine.
Oh, I am following , but could somebody pease explain to me why this magic propellor would increase the performance of the P-40 so much over just using a -73 Allison of 1325HP for takeoff as used in the P-40K? Granted it does tend to top out at around 12,000ft instead of the 21,000ft of the -45.
It maybe and it might not be, but the real point is that by the time the -7 Merlin showed up most military engines had a WER rating that was at least several hundred HP above the take off rating. Propellors were being fitted to get the most from this WER rating. The AAF was a little late getting into the WER game and didn't allow over boosting officially until sometime in 1942, WHile it might (or was) done at squadron level it means the AAF wasn't buying propellors fo HP ratings the engines weren't supposed to reach.
Propellors are also designed for the altititude at which they are going to work. Propellors for high altitude work needed more blade area for the same HP than a low altitude propellor would have. Using high altitude porpellors at low altitude might actually reduce performance. larger, heavier propellor has more drag and needs more power to rotate it in the thicker low altitude air.
By the way, the Allisons those trick propellors were going to go on in the P-38K were turbocharged engines rated at not just 1425HP for take off but 1425HP military power at 27,000ft and a WER of 1600hp. A new version of the Turbo (B-14) model was expected to give a service ceiling of 46,000ft. BOth 3 bladed 12' 6" and 4 bladed 12' 0" propellors were considered with the 4 blade version being able to utilze the power better especially as the altittude went up. These engines also used a 2;36 reduction gear to keep prop speed down.
Please note the -45 was good for 1150hp at 21,000ft.
No arguement with that, but I will point out that the Original Merlin in the Spitfire was rated at 1030hp at 16500ft but only 880hp for take off when using 87 octane fuel. So is it an 880HP engine or a 1030HP engine? and which rating at which altitude do you think the designed the propellor for?
True, it is what if. But there is the fantasy what if ( what if we had P-80s at Pearl Harbor)
and there is the "we could have done so much better if the generals in charge at the time weren't so stupid" what if's. The first is fun if a bit nonsense, the second sort of requires proving the generals actually were stupid. Or that the suggested "modifications" could actually be done in the suggested time line.
Or if the suggested modifications would actually work.
My self, I am partial to a MK II Westland Whirlwind as a what if but sticking with modified Peregrine engines and not trying to go to Merlins.
Actually, not exactly true.ClayAllison said:It would not have out-turned the 109 in Africa...
What about a hydraulic barometer-controlled supercharger drive like the 109? How difficult would hat have been to get for the Allison? Combined with a slightly larger single stage impeller and air to air inter-cooling should get it up a bit higher. The more efficient drive should partially compensate for the power loss from driving a larger blower. If you don't go to two stage you should only be adding about as much weight as you'd save by switching to 2x20mm cannon over the 6x.50 MG.
I have to disagree
According to Combat Aircraft of WWII by Bookthrift, the P-40F had a better power/weight ratio then the Me 109G
Lt James E. Reed of the 33rd Fighter Group mentions that he could outurn a Me 109 in his P-40