Which is the better fighter, P-40F or Typhoon?

[Ivan1GFP]

Hello BiffF15,
One of the really interesting things about the US Army and its choice of fighter development and designs was that Speed seems to be the most important consideration about all other characteristics.
The development of the P-40 from the P-36 gained some speed but lost a significant amount of climb rate and handling quality because of weight increases.
The P-40 as compared to the P-51 is a much more maneuverable and agile aircraft and roll rate is better except at very high speeds but with similar engine installations is usually about 30 MPH slower.

A little harsh I feel

Hello Glider,
I would have to agree on that point.

I believe the engine faults were resolved by mid 1943 but its worth remembering that the Typhoon always had a useful role to fulfil initially against the 190 tip and run attacks, then against the V1 and strike missions but she was nearly pulled from production.

The low altitude intercept mission is one that it shared with the Spitfire Mk.XII, so it was not the only aircraft capable of performing that mission.

I find it interesting that this is an issue as the Typhoon was quite agile and could match the 190 and 109 in a turn. It's turn circle was considerably better than the Tempest

I actually haven't had much luck in finding a good tactical evaluation of the Typhoon. I did find a description by one of its pilots in a video who described it as "clumsy" but I don't know if he was just referring to the cockpit arrangement or general handling. We already know the roll rate was poor. As for having a turn radius better than the FW 190, that is not a particularly great achievement. I am somewhat surprised that it could match a 109 (which model?) in a turn? I know that a Me 109G-6/R6 was tested against various British and American fighters and even with cannon pods under the wings, it turned better than the Mustang. Unfortunately it was one of the lower powered versions and probably why everyone thinks the 109G was so slow.

Probably because Europe was the most dangerous environment for GA aircraft and the RAF needed it's best and most robust aircraft for the role. The AA was thicker and the enemy fighters generally had a higher performance than the Japanese and Italian fighters. It should be noted that the USAAF didn't use the P39 or P40 over western Europe and even the P38 was replaced fairly quickly with the USAAF relying mainly on the P47 and P51, so they had the same thought.

This is somewhat of a contradiction because an aircraft with high performance isn't really needed for the Ground Attack role, especially since by that stage of the war, the Allies had pretty good air superiority. (Think IL-2 Sturmovik)
It is also worth noting that the choice of US Army fighters for western Europe were determined in the later stages of the war by their compressibility effects. The P-51 suffered least loss of control in a high speed dive, the P-47 had a lower speed for compressibility even though it could recover with the dive flaps added with the later aircraft. Without dive flaps, it was in the same situation as the Typhoon and had to ride down to lower altitudes to recover. The P-38 was too close to its compressibility limit even flying straight and level at high altitude.
Knowing this, and knowing that operations were at lower altitudes in the Pacific, one has to wonder why the much more altitude capable Spitfire Mk.VIII was sent rather than the Typhoon.

As for the last comment. The Typhoon was being replaced by the Tempest, a much higher performing aircraft and the Typhoons day was past, and that's why they were scrapped. That's why so many thousands of combat aircraft were scrapped of all kinds.

Many aircraft were scrapped at the end of the war, but some of the more useful though not necessarily current aircraft ended up as foreign military sales. Many countries with their new air forces were desperate for aircraft of all kinds. Older Spitfires made it to quite a few places. Macchi even rebuilt their old C.202 to C.205 standard and sold them. In that environment, one has to wonder if there was some other reason why all Typhoons were scrapped.

- Ivan.

 

[Shortround6]

Shortround,

The engine you pictured is not the engine I mentioned. In fact, it was never used in the P-40...at least not that version.
...and the link to the manual...???...why are we concerning ourselves with series of V-1710's that weren't used in the P-40?
I thought the picture I posted would show why the P-40 would need mods to house a two-stage SC...I even explained it.
I don't understand why you posted what you posted?...I respect your knowledge and Google-foo, but I am really at a loss here...???


Elvis

We are not really disagreeing.

The three P-40Q prototypes used Allison engines with normal reduction gears (sort of, one or more may have used a 2.36 reduction gear) on the front of the engine, however they used superchargers much like the ones in pictures/manual. Instead of the two impellers being in the same housing Allison put the first stage in it's own housing and drove it with a driveshaft and hydraulic variable speed drive (like a DB 601-605). Trying to find pictures of the engines used in the P-40Qs or the P-51J (which first flew in Aug 1945) or the F-82 is rather difficult and the only other plane that used the 2 stage Allison was the P-63 King Cobra, so be default, You wind up with pictures of the E series engines to try to show the supercharger/s.
I would note that there were at least two different setups for these two stage engines, One had the Carburetor between the stages (much like the P & W Engines) and the other had the carburetor mounted on the first stage (rear most compressor.)

You would need mods to the airframe. Modifications were done, Modifications were also done to the Spitfire and the Mustang to mount engines with two stage superchargers.

I am trying to point out that the mods, while possible, are extensive and are probably not worth it. And forstall arguments that say "they did it on the Mustang"

You can do a lot of things if you don't care about the cost (both of the item and cost of retooling a factory and lost production).

 

[Glider]

The low altitude intercept mission is one that it shared with the Spitfire Mk.XII, so it was not the only aircraft capable of performing that mission.

True but the Spit XII was a short term development whilst they concentrated on getting the Spit XIV right and I don't think many people would argue that this wasn't the right decision.

I actually haven't had much luck in finding a good tactical evaluation of the Typhoon. I did find a description by one of its pilots in a video who described it as "clumsy" but I don't know if he was just referring to the cockpit arrangement or general handling. We already know the roll rate was poor. As for having a turn radius better than the FW 190, that is not a particularly great achievement. I am somewhat surprised that it could match a 109 (which model?) in a turn? I know that a Me 109G-6/R6 was tested against various British and American fighters and even with cannon pods under the wings, it turned better than the Mustang. Unfortunately it was one of the lower powered versions and probably why everyone thinks the 109G was so slow.

No one is pretending that the Typhoon was a ballet dancer kind of fighter. It certainly couldn't turn with a Spit but it could hold one in its sights long enough for a burst, and with 4 x 20mm one burst may well be enough. I also agree that turning with a FW may not be fantastic, but in the real world that was quite sufficient. As for the 109 it was a matter of speed. At slower speed the 109 had a clear advantage but its controls became very heavy at speed and if the Typhoon could avoid a low speed engagement, then it had the advantage. US test pilots who flew the Typhoon and the Tempest all made the observation that the Typhoon had the advantage in a turn.
This link may help
http://www.wwiiaircraftperformance.org/tempest/Tempest-V_Eng-47-1658-C.pdf

This is somewhat of a contradiction because an aircraft with high performance isn't really needed for the Ground Attack role, especially since by that stage of the war, the Allies had pretty good air superiority. (Think IL-2 Sturmovik)

The main danger wasn't in German Fighters, it was in the Flak. The IL 2 could take a huge amount of damage that I am sure everyone can agree, but its about the same size and performance as a Fairy Battle and it is going to take hits, lots of them. The Typhoon is going to take less hits as its a much more difficult target and it was well protected with a considerable amount of extra protection. Plus of course if they did meet German fighters, the Typhoon had a much better chance and if all else failed, could simply run for it.

It is also worth noting that the choice of US Army fighters for western Europe were determined in the later stages of the war by their compressibility effects. The P-51 suffered least loss of control in a high speed dive, the P-47 had a lower speed for compressibility even though it could recover with the dive flaps added with the later aircraft. Without dive flaps, it was in the same situation as the Typhoon and had to ride down to lower altitudes to recover. The P-38 was too close to its compressibility limit even flying straight and level at high altitude.
Knowing this, and knowing that operations were at lower altitudes in the Pacific, one has to wonder why the much more altitude capable Spitfire Mk.VIII was sent rather than the Typhoon.

Whatever the technical reasons for the choice of aircraft, they were chosen for their suitability for the area of combat. For the RAF over Europe the Typhoon was the aircraft of choice and for the USAAF it was the P47 for the GA role.

 

[Greyman]

The low altitude intercept mission is one that it shared with the Spitfire Mk.XII, so it was not the only aircraft capable of performing that mission.

I actually haven't had much luck in finding a good tactical evaluation of the Typhoon. I did find a description by one of its pilots in a video who described it as "clumsy" but I don't know if he was just referring to the cockpit arrangement or general handling. We already know the roll rate was poor. As for having a turn radius better than the FW 190, that is not a particularly great achievement. I am somewhat surprised that it could match a 109 (which model?) in a turn? I know that a Me 109G-6/R6 was tested against various British and American fighters and even with cannon pods under the wings, it turned better than the Mustang. Unfortunately it was one of the lower powered versions and probably why everyone thinks the 109G was so slow.

This is somewhat of a contradiction because an aircraft with high performance isn't really needed for the Ground Attack role, especially since by that stage of the war, the Allies had pretty good air superiority. (Think IL-2 Sturmovik)
It is also worth noting that the choice of US Army fighters for western Europe were determined in the later stages of the war by their compressibility effects. The P-51 suffered least loss of control in a high speed dive, the P-47 had a lower speed for compressibility even though it could recover with the dive flaps added with the later aircraft. Without dive flaps, it was in the same situation as the Typhoon and had to ride down to lower altitudes to recover. The P-38 was too close to its compressibility limit even flying straight and level at high altitude.
Knowing this, and knowing that operations were at lower altitudes in the Pacific, one has to wonder why the much more altitude capable Spitfire Mk.VIII was sent rather than the Typhoon.

Many aircraft were scrapped at the end of the war, but some of the more useful though not necessarily current aircraft ended up as foreign military sales. Many countries with their new air forces were desperate for aircraft of all kinds. Older Spitfires made it to quite a few places. Macchi even rebuilt their old C.202 to C.205 standard and sold them. In that environment, one has to wonder if there was some other reason why all Typhoons were scrapped.

Early Typhoons had a good 20mph on the Spitfire XII under 5,000 feet ... assuming +7 boost. It would have been a good 30 mph with +9 boost.
EDIT: looking at the graphs that's probably a bit optimistic in favour of the Typhoon. Probably more like 15 and 25 mph respectively.

I agree the AFDU evaluations involving the 109G seem to be quite pessimistic compared to its potential. My general impression reading anecdotes over the years is that the 109 was a tough opponent in the comparatively rare occasions it made the (generally unwise) decision to stick it out and fight. My impression from the Typhoon pilots accounts I've read is that they were roughly equal to the 190 in turn, but the 109 would best them. That said, as long as the tactical situation was at least on an even footing it seemed like Typhoon squadrons were quite happy to charge right into 109s/190s.

I would disagree with the statement that 'high performance isn't really needed for the Ground Attack role'. Would Il-2s not have been massacred over NWE at a rate that the Western Allies wouldn't accept? Certain types of targets would be great, but attacking heavily defended targets like an important bridge would be a nightmare with Il-2s.

I imagine the main reason the Typhoon didn't go to the Far East was for supply and maintenance considerations. Also one of the main frustrations of the RAF in Singapore/Burma/etc. from '41 to '44 was getting fighters in the proper place fast enough and high enough to make an interception. They had been pleading for Spitfires for years and even the smattering of Spitfire Vs in 1943 wasn't the complete answer (with the radar coverage available). The Spitfire VIII was just what the doctor ordered.

I think the main reason the Typhoon disappeared so quickly was because there was no point to it with the Tempest around, and it had a lot of tiring, negative qualities that weren't worth putting up with at all in peacetime. Maintenance issues, vibration issues, CO contamination issues ...

 

[Elvis]

We are not really disagreeing.

The three P-40Q prototypes used Allison engines with normal reduction gears (sort of, one or more may have used a 2.36 reduction gear) on the front of the engine, however they used superchargers much like the ones in pictures/manual. Instead of the two impellers being in the same housing Allison put the first stage in it's own housing and drove it with a driveshaft and hydraulic variable speed drive (like a DB 601-605). Trying to find pictures of the engines used in the P-40Qs or the P-51J (which first flew in Aug 1945) or the F-82 is rather difficult and the only other plane that used the 2 stage Allison was the P-63 King Cobra, so be default, You wind up with pictures of the E series engines to try to show the supercharger/s.
I would note that there were at least two different setups for these two stage engines, One had the Carburetor between the stages (much like the P & W Engines) and the other had the carburetor mounted on the first stage (rear most compressor.)

You would need mods to the airframe. Modifications were done, Modifications were also done to the Spitfire and the Mustang to mount engines with two stage superchargers.

I am trying to point out that the mods, while possible, are extensive and are probably not worth it. And forstall arguments that say "they did it on the Mustang"

You can do a lot of things if you don't care about the cost (both of the item and cost of retooling a factory and lost production).

You know, I may recant my earlier post, but only slightly.
Yes, mods will need to be done to the airframe, but they may be minimal changes.
My remarks were based on a cutaway (different from the one I post earlier) I found at the old "P40.com" website that showed the area behind the engine was so small and so stuffed with....stuff that there was absolutely no room for a second impeller, but I just found this pic...check this out....

...the plane shown is identified as the very plane that we're supposed to be talking about, the P40F.
Notice the area behind the engine.
If Allison could've been persuaded to adopt the same two impeller layout that Rolls-Royce did, there's a very good chance that a second impeller could've been installed with a minimum of changes to the airframe, if any at all (maybe a couple of inches added to the engine mounting arms)......hmmm, very interesting indeed.


Elvis

 

[Shortround6]

Well, you still have the CG problem (V-1650-3 engine weighs 1700lbs compared to the 1510lbs of a V-1650-1)
The need for bigger radiators and oil coolers.
The need for the intercooler radiator.

The naked powerplant (no cowl or fuselage parts) for a P-51B was around 540lbs more than the power plant (naked) weight of a P-40F.

Not sure you want to use the engine mount for a 1300hp engine on a 1600hp engine either

 

[Elvis]

...rats, forgot about the weight penalty.

 

[wuzak]

The Merlin 2 speed single stage engines were 71" long. The 2 stage Merlins were 88.7" long according to Lumsden. http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Merlin.pdf has the 2 stage Merlin at 78" long, while the 130 series is shown at 88.7".

Whitney's Vees for Victory doesn't seem to list external dimensions, except to say that the 2 stage V-1710 was "considerably longer" than the 2 stage Merlin.

 

[tomo pauk]

Data about US-produced engines' weights and dimensions and a lot more : link
There was also a single PDF with all of these data sheets, but I'm not able to locate it right now.

 

[wuzak]

Data about US-produced engines' weights and dimensions and a lot more : link
There was also a single PDF with all of these data sheets, but I'm not able to locate it right now.

Thanks Tomo.

Looks like single stage V-1710-F series engines varied between about 85" and 89". For the single stage engine.
The long nose (C series) were about 94.5" long. And nearly 98" in the YP-37!

The two stage engines varied between 98" (carburetor between stages) and 107" (carburetor behind auxiliary stage).

The P-40Q engines (V-1710-101 and V-1710-121) were 101.25" long.

In contrast, the V-1650-1 is listed as 79.75" long, the -3 and -7 were 87.11" long and the -9 was longest at 89.14".

The space in the P-40F pictured above is probably because the V-1650-1 is several inches shorter than the standard F-series V-1710.

It looks like the single stage Allison is around the same length as a two stage Merlin!

The Allison fitted to the P-40Q was 14" longer than the V-1650-1 in the P-40F.

 

[Ivan1GFP]

You know, I may recant my earlier post, but only slightly.
Yes, mods will need to be done to the airframe, but they may be minimal changes.
My remarks were based on a cutaway (different from the one I post earlier) I found at the old "P40.com" website that showed the area behind the engine was so small and so stuffed with....stuff that there was absolutely no room for a second impeller, but I just found this pic...check this out....

View attachment 533237

...the plane shown is identified as the very plane that we're supposed to be talking about, the P40F.
Notice the area behind the engine.
If Allison could've been persuaded to adopt the same two impeller layout that Rolls-Royce did, there's a very good chance that a second impeller could've been installed with a minimum of changes to the airframe, if any at all (maybe a couple of inches added to the engine mounting arms)......hmmm, very interesting indeed.


Elvis

Hello Elvis,
I believe that picture is missing some stuff that would need to be there for the engine to run. Your image actually looks more like the Allison radiator and oil cooler setup.
Keep in mind that the Merlin had its carb intakes down low and there would be a mess of ducting that isn't in the photograph right now. That isn't to say that it isn't possible to work around it, but it does add to the clutter.
Please see the photograph attached.

As for weight differences with the Merlin versus Allison, I believe on the P-40F and P-40L, the engine was shifted back very slightly to maintain CoG. Also, if the radiators need to be enlarged, there is plenty of room under the Wing Roots where there is basically nothing but a fairing on most P-40s though it might begin to interfere with a belly tank or bomb. There already was a bit of a change in the fairing configuration for the F and L models to fit the different radiators.
When mounting the radiators on the Merlin P-40, the designers seem to have chosen to make the nose considerably deeper and shortened the distance to the radiator flaps. It seem to me that this would allow for space for a higher capacity radiator or for the core to be pushed back a bit to adjust CoG.

- Ivan.

 

[Ivan1GFP]

Here is another image of a Merlin radiator along with side views to compare the location of the radiator flaps.
The flaps are much further forward on the P-40F than on P-40N so there appears to be room behind where the P-40 radiator is now.

- Ivan.

 

[Shortround6]

I would note that fuel management (order fuel tanks were used) was different on the Merlin powered P-40s.
After taking off on the forward tank and using the belly tank (if present) the rear fuselage tank was taken down to 35 gallons US (29 imp) and then the forward tank was emptied followed by the rear wing tank leaving the 35 US gallons in the rear tank as reserve,

On Allison powered planes the rear fuselage tank was emptied before switching the rear wing tank leaving the forward wing tank as the reserve,

The single stage Merlin planes were using 210lbs worth of fuel as ballast to help the change in CG caused by using the single stage Merlin engine.

Without quite a bit of shifting things about and/or some major modifications you are going to need hundreds of pounds of ballast to get a two stage Merlin P-40 to fly right.

 

[Elvis]

Shortround6,

According to this chart, it appears the V-1650-1 may have had a two-speed SC.

-------------------------------------------------------------------------------------------------------

Ivan,

Thank you for posting those side views of the various P-40 models.
It appears the fuselage was indeed modified during the plane's existance.
I never noticed that before, but always thought the "-B's" looked "odd"....now I know why!

 

[Ivan1GFP]

Hello Elvis,
Yes, the Merlin P-40s did have a two-speed supercharger.
By my understanding, from the P-40C to P-40D, the fuselage modification was to replace the top half behind the firewall ABOVE the Fuselage Reference Line. Below this joint, everything was still the same.

Hello Shortround6,
210 pounds is just about the difference in weight between equivalent Allison and Merlin versions of the P-40.
From the sounds of it, there were no significant modifications to adjust the CoG with the Merlin installation and yet the aircraft was obviously still flyable with minimal fuel.
The big question would be whether or not there was room behind the current location of the engine for the larger 2 stage supercharger.
If there was, and there were no issues in relocating equipment that was already there, then the additional weight would make very little difference because it would be at the current CoG of the aircraft.
If there was no room and the engine had to be relocated further forward, then life would get ugly pretty quick unless folks were willing to relocate the cooling system back to the belly where it was in very early P-40 designs.

- Ivan.

 

[Shortround6]

From the sounds of it, there were no significant modifications to adjust the CoG with the Merlin installation and yet the aircraft was obviously still flyable with minimal fuel.
The big question would be whether or not there was room behind the current location of the engine for the larger 2 stage supercharger.
If there was, and there were no issues in relocating equipment that was already there, then the additional weight would make very little difference because it would be at the current CoG of the aircraft

Well, there is flyable and there is combat/acrobatic flyable. The French crashed a few radial engine Hawk 75s by trying acrobatics with the fuselage (rear) tank full.

The room for the supercharger is one thing but even if you have the room, trying to use a 3 blade propeller on a V-1650-3/7 is not going to give you the performance you want.
The Prop on a P-51B was about 100lbs heavier than prop from a P-40D/E and and 60-70lbs heavier than from a late model P-40. You need a larger radiator and more coolant and the whole intercooler set up.

Now there are a few things that can be moved.

On the P-36/P-40 the oil tank bounced back a forth like a ping pong ball.
On the P-36 it is between the engine and the pilot.
On the long nose P-40 it was behind the rear fuselage fuel tank (filler at the very rear of the canopy)
On the P-40D/E and later it was back behind the engine (or firewall?) perhaps where the .50 cal cowl gun ammo bins were?

Point is without either relocating the radiators/oil coolers or doing some other drastic surgery the plane is going to be very nose heavy.

The Mustang and Spitfire already used rear radiators/oil coolers and made them bigger and added the intercooler radiator which helped out but may not have been the total solution.

A MK IX Spit carried five 17.5lb ballast weights in the tail.

 

[Ivan1GFP]

Well, there is flyable and there is combat/acrobatic flyable. The French crashed a few radial engine Hawk 75s by trying acrobatics with the fuselage (rear) tank full.

Hello Shortround6,
The issue you are describing with a full Fuselage tank sounds like just the opposite situation we would be running into with a Merlin P-40. The CoG of the Hawk 75 is way too far aft while the CoG of P-40F is further forward than we would like.
The only problems I can think of is if there is not enough elevator authority to hold the nose up at low speed or flare or perhaps a little too much stability for good maneuverability.

The room for the supercharger is one thing but even if you have the room, trying to use a 3 blade propeller on a V-1650-3/7 is not going to give you the performance you want.
The Prop on a P-51B was about 100lbs heavier than prop from a P-40D/E and and 60-70lbs heavier than from a late model P-40. You need a larger radiator and more coolant and the whole intercooler set up.

What is really needed in this case is a Propeller and Reduction Gear that gives a significantly higher power coefficient.
Whether it has three blades or four or five really doesn't matter much except that more blades tends to make the whole prppeller heavier. I haven't really looked at the ground clearance with the Fuselage in a level attitude, but if it allows, a slightly longer propeller blade would absorb the extra power. Wide chord blades such as from the P-38 Lightning (still just 3 blades) might be another solution. The Lockheed Ventura had a lot more power but did not have the room to swing a larger propeller so also had to go to wide chord blades.
Regarding Radiator and Intercooler, an aft mounted setup might work if no one is concerned with losing the Belly Tank or perhaps radiators in the wing roots as in the P-40Q would work without giving up he centerline rack.

FWIW, I am under no illusions that this would be a feasible project.
The Merlin engines were not really available (They were already claimed by Mustangs, Spitfires, and Lancasters) and the US Army always prized speed above everything else in fighter and there was no way a P-40 was going to be as fast as the P-51 without becoming an entirely different aircraft.

- Ivan.

 

[michael rauls]

Just a thought/ question for those with more engineering knowledge than myself.
Couldn't the center of gravity have been maintained by lengthening the aft section of the fuselage and or additional armor plate behind the pilot. Sort of ballast with an additional benefit.

 

[Shortround6]

It is all about movement arms, think kids teeter-totter/see-saw ride. the further away from the CG the more effect the same weight has.
And any added weight as ballast affects climb and turn and landing (stall) speed.

 

[Ivan1GFP]

Just a thought/ question for those with more engineering knowledge than myself.
Couldn't the center of gravity have been maintained by lengthening the aft section of the fuselage and or additional armor plate behind the pilot. Sort of ballast with an additional benefit.

Hello Michael Rauls,
Your idea is sound, but the problem is as Shortround6 describes: a matter of how much weight and how far from the Center of Gravity. The swapping of a Merlin and Radiator assembly for the Allison and Radiator assembly added quite a bit of weight very near the front end of the aircraft. I had mis-remembered earlier but the actual weight increase was quite a bit more than I had thought: 6702 pounds Basic Weight for a P-40E to 7089 pounds for the very similar P-40F (387 pounds).
If you look at where the engine is relative to the CoG and note that the Fuselage (aft) Fuel Tank is nearly the same distance in the opposite direction, you can see why fuel can serve as ballast to offset the engine weight.

The problem is that the engine and radiator weight do not change in flight while the fuel is a disposable load and the aircraft grows increasingly nose heavy as the fuel is burned off. How bad it would get depends on how effective the elevators are at low speed.
This can be increased by airflow coming off the propeller but if the engine fails, recovery may be impossible. A rather famous pilot named Wiley Post was doing this for a while with an aircraft that was very nose heavy until he had an engine failure. He could not prevent his plane from diving into the ground and he and his passenger Will Rogers both died in the crash.

As for adding armour plate, the P-40 was pretty robust as it was and didn't need any more unnecessary weight.
Increasing the length of the tail was done at one point, but light structure doesn't significantly change the CoG.
To do things right, would mean that existing heavy non-disposable components need to get moved aft or additional equipment that may be needed for the new engine gets added well behind the CoG.

That is the problem as I see it. The end result would be that without a serious aerodynamic redesign, it still wasn't going to have the speed that the customer wanted.

- Ivan.