Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained) (3 Viewers)

[P-39 Expert]

Yes, The list is upthread somewhere but here it is again.

This was serial number 41-38291, a P-39D-1. first in standard configuration and then modified.
Removal of the four wing guns and supporting accessories, all of the gear box armor plate, the oxygen system, all radio equipment, all instruments except the altimeter, the airspeed indicator, engine manifold pressure gage, tachometer, temperature and pressure gauges; all tools and fixed equipment not essential for flight at 5,000ft, all ballast and four of the eight self-sealing fuel cells. This saved 1287lbs. On page 159 of "Cobra!" by Birch Mathews.
The only performance figures given are for time to 5,000ft, radius of turn and stalling speed. Time to climb 5,000ft dropped from 2 min 34 sec to 1 min 54 sec.

One test example. One. Never intended as an operational airplane.

 

[P-39 Expert]

Your original claim was "Yes the British were still using 30calMGs after the BoB, but the AAF WAS NOT." Again, when shown that you were wrong, your changed your claim, as you always do. 1/5 of USAAC fighters in Philippines on 7 Dec 1941 were P-40Bs (18) and 1/5 P-35s (18), and there were definitely P-40Bs on Oahu.

And most of the great aces of the WWII acknowledged that surest way to make a kill was open fire at close range, 200 yds was a good range to make a kill in early 40s. And on effectiveness of the .303, on 6 Jan 1940 Sarvanto shot down six Soviet DB-3Fs, these had armour and self-sealing fuel tanks, in five minutes while flying in Fokker D.XXI, 4 7.7 mm Brownings. And those six were not only claims, all six wrecks were found and nowadays we know from Russian documents that only one of 8 DB-3Fs of that formation returned and 7 were shot down the 7th by Sovelius. Sarvanto was exceptionally good shot and as Finns were trained opened fire at close range and probably all or three of his mgs were loaded with Italian APIs, the 4th might have been loaded with trackers. The downside of the close range tactic was that Sarvanto's plane was hit 23 times during the engagemant.

If I'm reading your post correctly there were 36 operational P-40s and P-35s with 30calMGs? Out of 100000 AAF and USN fighters with 50cals and or cannons? That's .00036%.

200yds was way too short ranged. One had to get within 200yds of a fighter to have a good chance at a victory? Or within 200yds of a bomber that was returning fire? The 30s didn't have enough hitting power or range. That's why the AAF/USN used 50calMGs and the British progressed to the 20mm cannon.

 

[pbehn]

My point is: British were specifying 30cals on P-400s when shortly the AAF/USN would move on to 50cals and cannon.

A 1942 P-39/400 at 7150lbs looks pretty good against P-38s since they weren't in combat until late 1942. P-47 was not in combat until spring 1943. Would outclimb a Mustang I and go about the same top speed. Spitfire IX started in mid '42 but production didn't get rolling until :ate '42. Would outclimb a Typhoon and about as fast. As far as a FW190A5 it would be outclimbed by a 7150lb P-39/400.

Shortly the British would be specifying cannon so if you dont like .303s put in the cannon. There were 6 squadrons of Mk IX Spitfires at Dieppe along with six squadrons of Mustang Is. Shortly after a Spitfire IX intercepted a Ju 86 at 42,000ft Where does your P-39 fit in here?
It didnt go "about the same top speed" as a Mustang I it was slower and the Mustang I could go prodigious distances carrying cameras, guns, cod pieces and false legs. There is no virtue in outclimbing a Typhoon or Mustang, you are climbing into your adversary's strong suite.

 

[P-39 Expert]

Uh... what?

I see you cherry pick around the P-40 and P-51 marques that were armed with .30's which surprises me not in the least.

Not to mention that the original F4U design used .30's as did the F2A.

As for the Airacobra, keep the wing guns, ditch the dumb cannon and replace it and the two nose guns with .30's and you'd have a 7 gun fighter with all the same caliber weapons (read same trajectory/ballistics) and a sh!t load of ammunition and turn it loose against the IJN/IJA.

And on another note, to say that IFF isn't needed is down.right.stupid.

I'm pretty sure Bifff (with 3 'f's) has already given you the reason you don't want to delete the IFF, but hey, why listen to an experienced fighter pilot amiright? Ah yes, he didn't fly P-39's and he's just Joe Pilot anyway so we can discount his opine on that.

How many P-40s with 30calMGs actually got into combat with the AAF/USN? The Mustang I with the 30s was an export model for the British.

Original F4F with 30s was a prototype. No operational F4Us had 30s. Did the F2A actually see combat with the USN?

An Airacobra with 7 30calMGs is absolutely the lamest idea ever.

If you don't have radar at your base then USING IFF is down.right.stupid. Your words, not mine.

 

[Milosh]

Out of 100000 AAF and USN fighters with 50cals and or cannons?

The USAAF and USN had 100,000 fighters in 1941?

 

[Milosh]

Never suggested a 1942 P-39 could be used as a bomber escort.

Sure you have.

 

[pbehn]

If I'm reading your post correctly there were 36 operational P-40s and P-35s with 30calMGs? Out of 100000 AAF and USN fighters with 50cals and or cannons? That's .00036%.

200yds was way too short ranged. One had to get within 200yds of a fighter to have a good chance at a victory? Or within 200yds of a bomber that was returning fire? That's why the AAF/USN was using 50calMGs and the British progressed to the 20mm cannon.

To validate your claim you need to find all the aircraft in US service in Nov 1940 with 0.5" and 0.3"

It was obviously the other way around, the USA themselves werent "using" anything in anger until Dec 1941, by that time all the new British fighter were or could be fitted with cannon.

 

[Milosh]

Did the F2A actually see combat with the USN?

Yes.

 

[Just Schmidt]

If I'm reading your post correctly there were 36 operational P-40s and P-35s with 30calMGs? Out of 100000 AAF and USN fighters with 50cals and or cannons? That's .00036%.

Are you 100% percent sure you double-checked your math on this one?

 

[P-39 Expert]

Lets try again.
P-39K at 6663lbs tactical empty from the weight chart in the manual.
Take out 100lbs worth of .30 cal guns or even add another 20lbs for "extras"
take out 100lbs of armor. leaving you with what the P-39C had.
take out 45lbs for IFF, that seems to be the highest figure.
you are down to just under 6400lbs
now add 720lbs of fuel.
OOPS, 7120lbs with NO AMMO.
That is a 1942 P-39.
No P-39M or N made it into combat in 1942.
You want to argue about P-40B&Cs and when they were used?
You have to take it on the other end.


I wonder why?
Again, look at the P-40N-1 to see what they did. And they used aluminum radiators/oil coolers and magnesium wheels in addition to restricting armament and ammo.

That ONE OFF saved 1287lbs. There simply isn't enough stuff to take back out of the plane to save 1000lbs without severely compromising operational use.
All but a few hundred pounds went back into the P-40N-1s once they got to the operational squadrons. Stupid squadron commanders?

Now let's finalize this weight discussion:
P-39K empty weight 5658lbs including voice and IFF radios, oxygen.
2x50calMGs + ammo 275lbs.
37mm cannon + ammo 300lbs
Gun sight 4 lbs
Armor plate & Glass 122lbs (as in N model without nose armor)
Pilot 200lbs
Oil 71lbs including the 2gal reduction gear box
Full internal fuel 720lbs
Gross weight 7350lbs
Deduct 50lbs for "misc. eq. for 30cal guns" from the P-39C pilot's manual. Shows 25lbs for 2x30s, K model has 4x30s. Without 30s you don't need their "misc. eq.".
Deduct 110lbs for IFF per AHT for 1942 NG
Deduct pilot 40lbs as earlier models used 160lbs incl. parachute
Gross weight 7150lbs-what I've been telling you all along.
Substitute 20mm cannon with 120rds ammo 200lbs. 20mm was more reliable in 1942, include 37mm cannon in M/N/Q models that didn't need any weight reduction.
Gross weight 7050lbs.

Straight from the Pilot's Manual. An armored warplane with self sealing fuel tanks and cannon/heavy machine gun armament. Optimal configuration for 1942.

 

[pbehn]

Now let's finalize this weight discussion:
P-39K empty weight 5658lbs including voice and IFF radios, oxygen.
2x50calMGs + ammo 275lbs.
37mm cannon + ammo 300lbs
Gun sight 4 lbs
Armor plate & Glass 122lbs (as in N model without nose armor)
Pilot 200lbs
Oil 71lbs including the 2gal reduction gear box
Full internal fuel 720lbs
Gross weight 7350lbs
Deduct 50lbs for "misc. eq. for 30cal guns" from the P-39C pilot's manual. Shows 25lbs for 2x30s, K model has 4x30s. Without 30s you don't need their "misc. eq.".
Deduct 110lbs for IFF per AHT for 1942 NG
Deduct pilot 40lbs as earlier models used 160lbs incl. parachute
Gross weight 7150lbs-what I've been telling you all along.
Substitute 20mm cannon with 120rds ammo 200lbs. 20mm was more reliable in 1942, include 37mm cannon in M/N/Q models that didn't need any weight reduction.
Gross weight 7050lbs.

Straight from the Pilot's Manual. An armored warplane with self sealing fuel tanks and cannon/heavy machine gun armament. Optimal configuration for 1942.

To do what?

 

[P-39 Expert]

Yes.

Well, when and where?

 

[pbehn]

duplicate

 

[pbehn]

Well, when and where?

Post # 1965
"Stop putting words in my mouth. I have never said that the P-39 was able to do the Mustang's job. I have said that P-39s could have escorted B-17/24s in Europe, certainly not as far or as well."

 

[Shortround6]

Now let's finalize this weight discussion:
P-39K empty weight 5658lbs including voice and IFF radios, oxygen.
2x50calMGs + ammo 275lbs.
37mm cannon + ammo 300lbs
Gun sight 4 lbs
Armor plate & Glass 122lbs (as in N model without nose armor)
Pilot 200lbs
Oil 71lbs including the 2gal reduction gear box
Full internal fuel 720lbs
Gross weight 7350lbs
Deduct 50lbs for "misc. eq. for 30cal guns" from the P-39C pilot's manual. Shows 25lbs for 2x30s, K model has 4x30s. Without 30s you don't need their "misc. eq.".
Deduct 110lbs for IFF per AHT for 1942 NG
Deduct pilot 40lbs as earlier models used 160lbs incl. parachute
Gross weight 7150lbs-what I've been telling you all along.
Substitute 20mm cannon with 120rds ammo 200lbs. 20mm was more reliable in 1942, include 37mm cannon in M/N/Q models that didn't need any weight reduction.
Gross weight 7050lbs.

Straight from the Pilot's Manual. An armored warplane with self sealing fuel tanks and cannon/heavy machine gun armament. Optimal configuration for 1942.

Wrong weights.
The IFF was 40 to 45 lbs,not 110.
140lb pilots in shoes and flight suits/ equipment are going to be scarce. And strangely, American P-39s with 20mm guns carried 70-88 lbs of ballast in addition to the gear box armor.
71lbs of oil is not enough for 120 gallons of fuel.

 

[Milosh]

Well, when and where?

Use your I-net search skills.

 

[pbehn]

Use your I-net search skills.

Forum search key word "escort" by poster P-39 Expert. It not only shows he said it but he also says he has said it before, I really dont know where this is going, its just trollery.

 

[Milosh]

He was asking about the F2A.

 

[P-39 Expert]

I wanted to see if the P-47 variant that was operational on say, Bastille Day 1943, was competitive in range to the Airacobra variant OPERATIONAL on that same day. I came up with P-47D -25RE (?) and the P-39D. I looked at the range charts for the P-47, no external fuel, on that section's second page. After some eye strain, I went out for errands. I think it was statute 760 miles, not nautical miles. So divide in half, 380 miles. Now eliminate the fooling around time, whatever percentage that is which would leave us with 275 miles.
I then started looking up the range charts of the P-39 and as the Lord is my witness, I didn't want to read anything more about the P-39.

I wanted to just briefly respond to your post. It's too late for that.
I understand that the distance to the target is not a straight line. Someone brought up the woefulness of the P-47's range in this, the P-39 thread. So I started to look for myself. I think the P-39's range was less than that. I have not yet completed my research. Nor will I ever.

P-47D-25 didn't get to combat until mid-'44. P-39D was operational mid-'42. That's two full years.

To get combat radius go to the Flight Operation Instruction Chart in the P-47 pilot's manual. Take total fuel including 110gal drop tank 415gal. Then compute the "fooling around time" as you put it by deducting the takeoff and climb allowance 45gal, 20 minute combat reserve 90gal, and 20 minute reserve for landing 25gal. The net fuel 255gal can be used for cruising is divided by 105 gallons per hour at 25000' yielding 2.4hours cruising time. Multiply by 285mph TAS cruising speed (190 IAS) for a total of 684mi. Divide by 2 for 342mi combat radius.

Put that into perspective with Berlin being 520mi from England. P-47 came up a little (a lot) short. This computation uses the most economical setting (105gph) for the P-47 at 25000'. Most charts give the P-47 with drop tank a combat radius of 375mi but that is still way short of Berlin.

 

[Juha3]

If I'm reading your post correctly there were 36 operational P-40s and P-35s with 30calMGs? Out of 100000 AAF and USN fighters with 50cals and or cannons? That's .00036%.

200yds was way too short ranged. One had to get within 200yds of a fighter to have a good chance at a victory? Or within 200yds of a bomber that was returning fire? The 30s didn't have enough hitting power or range. That's why the AAF/USN used 50calMGs and the British progressed to the 20mm cannon.

Lol, no it means that on 7 Dec 1941 40% of the USAAC first-line fighters in Philippines were armed with .300 mgs, Wiki says that most of USAAC fighters on Oahu were P-40Bs, I had exact numbers in my attic, but because you do not mind facts, why bother, you like to use wiki, so be it. Now that means that when the Pacific War began, most of the USAAC fighters there were armed with .300s (plus also with two 0.5s). That was over a year after the end of the BoB. You can read from the AHT that the USAAC got some 350 P-40s with .300 wing guns.

Maybe this thread gives to you some idea on air combat RAF Fighter Gunnery Analysis the main point to understand air gunnery and air combat is that to achieve a kill in 99.9% of the cases you must first hit the enemy a/c.