P-40 what-if

[Elvis]

...forgot to address this part...

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.

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.
The whole thing's about density per charge anyway, so whatever condition the engine finds itself in, I would think the cooling of the charge would still prove beneficial...EXCEPT, in extreme cold, like Alaska...but then, those planes would be spec'd differently anyway. Chances are the coolers may not even be present, or only one might be spec'd.



Elvis

 

[Elvis]

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 they learned that from Cleaveland, right?


Elvis

 

[Shortround6]

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

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.

 

[Shortround6]

...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.

You might want to tell that to the scores of peaple who over heated their cars in the American southwest while running their air conditioners full blast
things have gotten better with newer (post 60's?) cars but that is because they are putting in bigger radiators to begin with. replacing cooked engines under warranty probably got as espensive as the cost of slightly bigger radiators, not to mention the loss of reputation.

...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.

no there isn't but what type are you using? Most american planes used air to air intercoolers which means rather bulky ducts (which have to be kept air tight ) leading too and fro in the aircraft. Navy planes kept the intercoolers (and they did use two of them on the R-2800s) tucked sort of behind the engine next to the superchargers.
Merlin used a liquied cooled inter/aftercooler with the "radiator' next to the oil cooler in one of the under wing ducts/housings. Smaller and harder to hit but a single rifle bullet can take out the intercooler setup entirely rather than just degrade it a bit.

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..

Might work if you flew full throttle all the time......nope won't work then either.
In a full throttle climb max climb the airspeed is rather low, ussually under 200mph so the air flow through the various cooling systems is much lower than it is in a high speed dash. this is why most climb to altitude tests are conducted with radiator flaps and oil cooler flaps wide open (or cowling flaps on aircooled engines) while the speed tests are conducted with the flaps closed or at least closed to the oppoint of maintaing a certain max temperature. Drag goes up with the square of the speed so the extra drag at the low climb speeds isn't quite as important.
Cruising speeds present another problem. The engine is making much less power (and heat) than full throttle. in fact the engine can be in danger of being over cooled if run with all flaps wide open.
Part of the P-38s troubles in Europe in the winter of 43-44 as due to too much cooling of the intake charge in cruising flight leading to fuel condensing out of the mixture and puddling in the intake manifolds.
Post war commercial Merlins were actual fitted with intake charge heaters to solve similar problems in cruising flight.

 

[Elvis]

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.

Hey, that was quite interesting to read.
Thanks for posting that.
I had no idea the "two-stage" project went back that far.
The only thing I could find on production of the -45 was 1943.
Obviously, this concept had been "cooking" for a much longer time.

As for modifying the airframe, I didn't mean a drastic change to the cockpit location. Only about 3 or 4 inches.
This is assuming the pics I saw were accurate in showing a small bit of space at the rear of the engine compartment, which might be utilized to help house the extra length.
If that were, say, a 6" long space, and you push the cockpit back 4", you now have 10" of space to house the extra length in.
So now the front of the engine only sticks 12" past the front of the single stage engine, instead of 22".
This additional length, plus the extra 200 lbs. could be further balanced by an extension of the aft fueselage, but that extension wouldn't be quite as large, as if it had to counterbalance the additional 200 lbs., plus the full 22" of extra engine length.

I still say Clay was on the right path by introducing the idea of the H-S prop. My only stipulation is make it the same diameter and same number of blades as the C-E prop.
As for your HP comments, concerning the H-S prop, remember that the 4-bladed, 11'2" version was used on the P-51D...

...and it's Packard-Merlin engine only made 1490HP.
Therefore, I think a 3 bladed, 11' version will work nicely with 1325HP on tap.

As for your Intercooler question, I was thinking air-to-air, because of the fragility you mentioned with the liquid cooled version (however more effieicient it is), but I'll concede to dampers for the IA. I didn't consider night flying in winter-time conditions.





Elvis

 

[Shortround6]

Thank you for your comments.

As far as the propellors go you might want to check your HP figures. 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

 

[Elvis]

Thank you for your comments.

You're welcome, but why do I have this odd feeling that...

As far as the propellors go you might want to check your HP figures.

...YEP, here we go...

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.
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.
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.



Elvis

 

[Shortround6]

.

Which version of the Allison has been the main point of discussion since Clay resurrected this thread with the H-S prop idea ?

THe point is that I don't believe a "magic" propellor will really do anything for a 1942 Allison engine.

.In case you're not following, I was referring to the -45 version, when I quoted the 1325HP figure.

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.

.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.

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.

.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).

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?

.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.

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.

 

[Clay_Allison]

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.

The P-39 was great flying low altitude missions. The Russians loved it and there were several Russian Aces in it.

 

[Shortround6]

I still don't think you recognize that an American fighter capable of flying top cover would be an incredible asset in 1942..

I recognize that an american fighter capable of fly top cover would have been a great asset. I also recognize that it wouldn't have been a P-40 unless you stuck a rocket engine it. or used engines and fuel from 1944.

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).

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.

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.

Let me see if I really have this right: Can't out turn the 109, can't out climb it, can't out run it in level flight.
It can dive faster 485mph IAS for the P-40 vrs what for the 109s. Not a huge advantage. Far more durable, is that before or after you take out the armour and selfsealing tanks to lighten it up or have you given up on that idea?
What are sufficient numbers? Given Sufficient numbers(like outnumbering the 109s 10 to 1) and using appropriate tactics quite a few aircraft could have given a good acount of themselves.
Plese refrain from the hyperbole, it does your arguement no good. "...the P-40 could have given excellent account of itself against the best fighters of 1942 at all altitudes"

Really. it is better than Spitfires and FW 190s? and at all altitudes? Or some of these Russian planes like the LA-5s Or better at 30,000ft than a P-38?

The P-39 was great flying low altitude missions. The Russians loved it and there were several Russian Aces in it.

There Russian aces that flew I-16s, There might even have been 1 or 2 that flew I-153s
I am not sure what Russian use of P-39s really has to do with how practical or effective your proposed modifications to the P-40 are.

 

[Clay_Allison]

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.

If Merlins were available in sufficient quantity to supply the P-40 I'd have had no need to start this thread or chatter about Allisons with different dash #s.

I think that with a few small improvements, the P-40F was good enough.

The Allison -45 or -47 would be instead of the Allison -39.

Thanks for the idea, I just found a way that enough Merlins could have been made available.

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]

Play nice with Ford, have Packard build for England and Ford build for the U.S. and we have Merlins a-plenty.

 

[Shortround6]

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.

 

[Clay_Allison]

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.

Ford building R-2800s explains why the R-2800 never seemed to be in short supply.

So, if they negotiated the Packard deal in September 1939 (immediately following the invasion) instead of September 1940, the P-40F would have been available in January 1942.

It would have been eclipsed by the Mustang even earlier since the availability of Merlin Engines in quantity would possibly have led to the Mustang A being Merlin equipped form the beginning.

 

[Shortround6]

R-2800s were also built by Chevrolet (over 4,200), A special P&W plant in Kansas City (over 8,000) and Nash (just under 17,00).

Your time line might work except for a couple of details. In 1939 the Merlin MK XX (or Merlin 28 or -1) didn't exist as anywhere near a production engine. The MK X did. So you had a choice of either a single speed, single stage Merlin or a single stage two speed Merlin, niether of which showed that much more potential than the Allison. The Single speed Merlin is rated at 880HP for take off compared to 1040 hp for the Allison.

British sign contract for Mustang on May 29 1940.
"Ford announcement of "1000 planes a day" take place end of May/ Early June and falls through in days.
A Merlin "pattern engine" is in the US in the middle of June.
Packard is approached June 24, and starts work June 27 using Drawing that originally had been sent to Ford but it is not until Sept 13 1940 that the Formal contracts are completed. This might delay your time line by 2 1/2 months. Intial contract is for 6000 two speed single stage Merlins for the UK and 3,000 engines for th US.

US 1939-40 contracts for the P-40 were for 524 airplanes on April 26,1939. THe first 134 planes were paid for using FY-39 funds while the remaining aircraft (66 P-40s, 22 P-40Ds, 301 P-40Es) are paid for with FY-40 funds. The D-s and Es aren't delivered until mid/late 1941 becasue of delays in the F series engines. 131 P-40Bs and 193 P-40Cs are purchased using FY-41 funds as an interim measure. These were delivered in early 1941 before the D/E models. Army purchases first 5 -39 Allisons Jan 27 1940. they must have recieved a proposal for the engine sometime before that.

As a note to US opinion of the time, in May of 1941 the U.S. Office of Production Management told Gen. Echols, Cheif of the Material Division that "the Merlin engine borders so closely on obsolescence that it would not be econimical to spend time and money trying to improve it.... "

Late 1939 through 1941 was a great period of confusion on fuel. British were switching from 87 octane to 100 octane. Americans already used A 100octane fuel. Problem was that British 100 octane wasn't the same as American 100 octane. THe Americans had no requirement for rich mixture performance and specified a different chemical composition of the fuel. THis ment you could not use the same rich mixture maximium manifold pressure using the two different fuels. A real problem trying to develop service engines. It was found that British fuel actualy acted like 120-125 octane (or performance number) depending on batch. At least one batch of American fuel reportedly tested 100 octane lean and under 100 octane under rich conditions. Americans started specifing their fuel to a 100/125 standard while the British went for a 100/130 standard which the Americans later adopted. This took until vary late 1941 if not some time into 1942 to sort out.

While the Production planners in the US could decide on making R-2800s (or other engines) fairly early on and start planning on factories to make the engines the actual specifications for the engines were a little more in doubt as fuel situation was changing so fast. It was found that the liquid cooled engines would tolerate much higher boost pressures than the aircooled engines would.

I don't think the P-40F was going to be available much before it was without a lot more happening than just talking to Packard in 1939. While the P-40F was better than the E and early models it still didn't compete very well with the 109. It was just too large and heavy for the available power.

 

[Clay_Allison]

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.

 

[Elvis]

Sorry to intrude on the current discussion, but I felt that I had to post a retort.
Respond, don't respond, its not important right now. I just feel that the below quote needs to be addressed.

The post in question...

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.

My response...

Shortround6,

It seems you either completely misread my post or am intentionally responding in a way to sway the discussion in a way it was not intended. I don't know which, but you've done this before, so I'm becoming a little suspect of your actions.
In your response (quoted above) you go on about Merlin engines, but my only purpose for bringing up the Merlin is to show that the -45 Allison engine had enough ponies to use the version of the H-S prop I mentioned.
...and I understand what Clay was getting at, by mentioning the P-39.
The point here is that the P-51 never exists in the first place (or comes along much later than it actually did) because N.A. went ahead and built those P-40's for the British, instead of what really happened.
THUS, the P-39, with its big 37mm gun, becomes the Ground Attack / Bomber interceptor and the P-40 is then further developed into the Fighter interceptor / Bomber escort.
This is why I'm so keen on a combination of the IA version of the -45 engine and that H-S prop.
Because the idea IS to make the P-40 into a better high altitude fighter and the engine dates closest to a time period when that development work was being done (although I'd like it better a year or two earlier).


Elvis



Thank you for the space to post it, please continue on with your current discussion.

 

[Elvis]

It would not have out-turned the 109 in Africa...

Actually, not exactly true.
I have some video I copped off the TV about an Aussie pilot named Col Paye who collected and restroed warbirds.
The particular show I have dealt with a P-40 he found buried in Canada.
During the show, they interviewd a WWII Australian fighter pilot name Billy Gibbs, who (IIRC) was on hand when the P-40 was first rolled out and test flown, after the restoration was complete.
Gibbs himself said that the P-40 could out turn both the Spitfire and the 109....and he should know. He logged a bit of time in all 3 of those planes.



Elvis

 

[Shortround6]

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.

It won't do a thing for altitude performance.
a. it isn't more efficient than a gear drive in regards to power transmission. It will use more power to drive than a gear setup.
b. a larger supercharger of the same design will give you more volume of air but not more pressure.
c. the intercooler will help total power but won't actually change critical altitude much. The Jumo 211 was just about the ONLY engine ever to use an intercooler on a single stage engine. They add weight,bulk and drag and were ussually figured as not worth the actual HP improvement on single engine fighter aircraft.
d. Allison did use just about the same set up ( hydraulic) to drive the Auxilery stage of all their mechanical two-stage engines.
e.German engines used either 1.3 ata of pressure to make rated power or 1.42ata. The Merlin MK III used 1.423 ata. the Allison needed 1.48 ata to make 1150hp. The same design (pressure ratio) supercharger will always give the German engine a slightly higher critical altitude.
f. futzing about with guns will not solve the P-40s problem. The XP-40 prototype weighed 6,260lbs loaded with no armour or self sealing tanks, only 100 US gallons of fuel on board and a pair of .50cal guns with 200rpg. A Bf-109F-4 weighed 6,393lbs according to one source. The 109 is just going to have a better power to weight ratio no matter what is done to the P-40. The P-40C had an empty equiped weight of 5,812lbs. Put in a pilot, 600lbs of fuel (100 US gallons) and ammo and see what happens.

 

[vikingBerserker]

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

 

[Vincenzo]

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

The engine of P-40F it's less power of that Bf 109 G, The P-40F it's heaviest of 109 G, don't true at all you read