P-40s on Clark Field

[Bataan Jerry]

Does anyone know about the automatic gun charging systems on the early P-40s? (1941) How the guns were manually charged?

Among the many problems P-40 ground crews at Clark Field had in readying the pursuit squadrons for war in the fall of 1941 was the hydralics for the automatic gun charging system was linked to the landing gear. In the summer of 1941 word came from Wright Patterson to disconnect the gun chargers or the wheels could collapse. They solved the problem at W-P by October but no one informed Clark before war started.

Thanks if you can shed some light?

 

[fredleander]

Bartsch writes about this in his book "Doomed at the start" and "Every day a nightmare". They would charge the guns on the ground. If there was a malfunction in the air they had to land to recharge. This did not apply to the "B" version which could be recharged manually (the fifties). The .30 calibre wing guns lived their own lives. There were other problems with the fifties,, too. No testing, poor cleaning after storage, no bore sighting, sighting adjustments. Ammo not allowed to be used for these purposes.

Fred

 

[Bataan Jerry]

Bartsch writes about this in his book "Doomed at the start" and "Every day a nightmare". They would charge the guns on the ground. If there was a malfunction in the air they had to land to recharge. This did not apply to the "B" version which could be recharged manually (the fifties). The .30 calibre wing guns lived their own lives. There were other problems with the fifties,, too. No testing, poor cleaning after storage, no bore sighting, sighting adjustments. Ammo not allowed to be used for these purposes.

Fred

Hi Fred and thanks for your response. I read Bartsch's excellent book some time ago. My specific question is "How" were the guns "recharged?" Or "What' was necessary to achieve this? Can you add any insight to this?

I didn't know the 40s ever utilized .30 cal. All I've ever heard is they had three .50s in each wing.

Regards,

Jerry

 

[fredleander]

Pse disregard

 

[MIflyer]

Doomed at the Start says that the vast majority of the P-40's in the PI at the start of the war were P-40E's. I believe there was only one squadron of B models, and they had the .30 cal guns in the wings.

In contrast the P-40B was the only model in HI on 7 Dec 41, as well as P-36's and P-26's. That surprised me. I assumed HI would have the best and the PI only left-overs, but in fact the situation was the opposite. In the PI the P-26's had been given to the PI Air Force, but the USAAF in HI was still flying them, and relied upon the P Shooters heavily for patrols after most of the later airplanes were lost in the 7 Dec attack.

 

[fredleander]

Hi, Jerry!

To take the .30s first - The P-40 "B" and "C" versions had four .30s in the wings and two .50s under the engine cowling. The .30s could not be reloaded/charged in the air. If there was a stoppage it had to be remedied on the ground. The .50s, however, could be reloaded /charged manually by the pilot in the cockpit.

If you had read the Pearl Harbor story properly you would have learnt that pilots Taylor and Welch, in their P-40Bs, took off with only their wing guns - .30s - loaded. They landed later to have their .50 loaded up, too.

The P-40E had six .50s in the wings only. Their loading (charging) system was coupled through the same hydraulic system as the undercarriage. This connection was disrupted for the reason stated by you in your first post. With this the guns had to be charged/cocked manually by the weapons crews before take-off. Consequently, if there was a malfunction they had to land to have them recharged.

There were both "B" and "E" versions in service in the Philippines in December 1941. However, their problems were much more serious, technically, than at Pearl Harbor because many of the "E"s had just arrived, guns had not been sighted or properly cleaned from Cosmoline and the lack of .50 ammo prevented live-fire training.

Actually, the Philippine-based pilots preferred the "B" to the "E" because it was lighter, better climb, and the .30s were more reliable than the .50s because they had at least been fired. Their engines were also properly run in. Another problem with the "E"s.

Fred

 

[Bataan Jerry]

Doomed at the Start says that the vast majority of the P-40's in the PI at the start of the war were P-40E's. I believe there was only one squadron of B models, and they had the .30 cal guns in the wings.

In contrast the P-40B was the only model in HI on 7 Dec 41, as well as P-36's and P-26's. That surprised me. I assumed HI would have the best and the PI only left-overs, but in fact the situation was the opposite. In the PI the P-26's had been given to the PI Air Force, but the USAAF in HI was still flying them, and relied upon the P Shooters heavily for patrols after most of the later airplanes were lost in the 7 Dec attack.

==========

Hi and thanks for the remarks. Prior to August 41, all the PI got were obsolete cast-offs. That all changed in late summer. They then got the latest shipments of 40-Es.
I'm still looking for what exactly was the process to "charge" the guns? How did a pilot do that (manually) from the cockpit?

jk

 

[Bataan Jerry]

Hi, Jerry!

To take the .30s first - The P-40 "B" and "C" versions had four .30s in the wings and two .50s under the engine cowling. The .30s could not be reloaded/charged in the air. If there was a stoppage it had to be remedied on the ground. The .50s, however, could be reloaded /charged manually by the pilot in the cockpit.

If you had read the Pearl Harbor story properly you would have learnt that pilots Taylor and Welch, in their P-40Bs, took off with only their wing guns - .30s - loaded. They landed later to have their .50 loaded up, too.

The P-40E had six .50s in the wings only. Their loading (charging) system was coupled through the same hydraulic system as the undercarriage. This connection was disrupted for the reason stated by you in your first post. With this the guns had to be charged/cocked manually by the weapons crews before take-off. Consequently, if there was a malfunction they had to land to have them recharged.

There were both "B" and "E" versions in service in the Philippines in December 1941. However, their problems were much more serious, technically, than at Pearl Harbor because many of the "E"s had just arrived, guns had not been sighted or properly cleaned from Cosmoline and the lack of .50 ammo prevented live-fire training.

Actually, the Philippine-based pilots preferred the "B" to the "E" because it was lighter, better climb, and the .30s were more reliable than the .50s because they had at least been fired. Their engines were also properly run in. Another problem with the "E"s.

Fred

I've long-ago "properly" read about Welch and Taylor; maybe sixty years ago now, so those details may get a bit distant, thank you. Bartsch goes into great detail about the start-up problems of the Luzon pursuits. I haven't yet gleaned what was the actual physical process to manually "charge" the guns; especially if the pilot could do it for the .50s from the cockpit.

 

[Shortround6]

One the early P-40s (and the P-36s) the gun breeches actually protruded through the instrument panel

On the right hand gun the red handle to the right of the gun may be attached to the charging handle/cocking piece and a really good tug on the handle will pull the bolt back and cock the firing mechanism. It will also pull a round out of the belt and position it in the feedway, ready to chamber when the bolt goes forward. There should be similar handle for the left gun.

On the fixed guns the charging handle may have been deleted and the cable/charging mechanism attached to the charging slide to save space.

On some planes they tried to route cables from the wing guns to the cockpit but the cables sometimes bound up or kinked. Getting the needed force/leverage on the remote charging handles was a problem.
Some planes tried electric solenoids, hydraulic or pneumatic cylinders to charge the guns/clear jams but many times the increased maintenance was judged not worth the number of times that the mechanical systems could actually clear the gun (assuming the pilot could correctly identify which wing gun was malfunctioning). Mechanical systems have an upper limit to power, an angry/excited pilot might be able to exceed the force applied by the mechanical system.
Recocking or recharging the gun pretty much only works for misfires, there is no way to fix a kinked or twisted belt in flight on a fixed gun in the wing of a plane.
Waiting to charge the guns in the air was a safety measure. Moving across a rough field at 60-100mph might be enough to jar a bolt off the sear and allow a bolt to go forward or in the case of guns that fired closed bolt, jar the sear loose and allow the firing pin to go forward.

Hope this helps.

 

[fredleander]

I've long-ago "properly" read about Welch and Taylor; maybe sixty years ago now, so those details may get a bit distant, thank you. Bartsch goes into great detail about the start-up problems of the Luzon pursuits. I haven't yet gleaned what was the actual physical process to manually "charge" the guns; especially if the pilot could do it for the .50s from the cockpit.

Hi, we should be about the same age, then…...I, too, hope Shortround's reply clarifies the matter for you.

Nice illustration, Shortround!

Fred

 

[MIflyer]

Why not take a look at the P-40D/E Flight Manual? It is available on the site.

 

[fredleander]

Why not take a look at the P-40D/E Flight Manual? It is available on the site.

And here is a link for an AVG P-40B - or was it "C"? - Flying Tigers P-40 Tomahawk manual

I wasn't aware of it but the "B" .30 wing guns could also be charged from the cockpit by wire.

Which is, I suppose, why the wing .50s got an hydraulic charging system, these having a "heavier" mechanism.

Fred

P.S.: Shortround, does your cockpit show the charging handles of the .30 wing guns?

 

[Shortround6]

No idea, as can be seen it is a picture from the Naval aviation museum and it many not be complete, however there are four T handles, two on either side of the stick under the instrument panel that might be the charging handles.

 

[fredleander]

That conforms with the description in the AVG user manual. Thank you!

Fred

 

[MIflyer]

Turns out I have four different P-40 manuals as well as that Tomahawk manual. One is the Curtiss manual, one is the USAAF manual, and one is typewritten. Three of the manuals on the D, E, and later models say the guns are hydraulically charged by means of valves located below the main instrument panel. If the hydraulic pump fails they can be charged using the emergency hand pump.

Now, the 4th manual, the P-40 Training Manual says something different. The guns have to be charged manually on the ground. I do not know if this was an innovation to save weight and complexity , or an approach used just for training. See attached.

 

[Bataan Jerry]

Hi, we should be about the same age, then…...I, too, hope Shortround's reply clarifies the matter for you.

Nice illustration, Shortround!

Fred

thanks for the input

 

[fredleander]

The crucial word could be "charge" - as opposed to loaded and/or cocked as both the .30 1919 and the .50 M2 had a double loading sequence. First pulls the cartridge out of the belt and places it in a loading ramp. The second actually chambers the cartridge and cocks the weapon. I suspect the fifties, without knowing this, had to go through the first stage on the ground, the second to be initiated through the hydraulics, by the pilot. Might be the same on the thirties even if two pulls on the "T" handle might be the correct way.

The A and B of this is that the "B" version P-40 could reload/recharge manually in the air, the "E" version could not if the machine gun charging system was disconnected from the airplane's hydraulic system. Which was the case in the Philippines in December 1941. Blame it on MacArthur.

Fred

 

[Deuelly]

Does anyone know about the automatic gun charging systems on the early P-40s? (1941) How the guns were manually charged?

Among the many problems P-40 ground crews at Clark Field had in readying the pursuit squadrons for war in the fall of 1941 was the hydralics for the automatic gun charging system was linked to the landing gear. In the summer of 1941 word came from Wright Patterson to disconnect the gun chargers or the wheels could collapse. They solved the problem at W-P by October but no one informed Clark before war started.

Thanks if you can shed some light?

The gun chargers where not directly connected to the landing gear in any way. They had there own feed from the hydraulic system and the lines went directly from the chargers to the guns. You could have a leak and lose fluid in the system but that would not cause the gear to collapse. The gear on a P-40 will stay down with no fluid in the system.

The technical order to remove them came out in October 28, 1942.

Brandon

 

[Deuelly]

P-40 lower charger panel with charging instructions, and gun charger pics.

Brandon

 

[fredleander]

As I understand it, the reason behind the commotion was that it was suspected that the gun charging mechanism, also part of the plane's hydraulic system, in some way could have, at one stage, created a problem for the under-carriage part of the hydraulic system. Exactly how this came about I do not know but it was allegedly the reason why it was decided, for a period, anyway, to disconnect the charging mechanism from the hydraulic system. As we know, when this maintenance procedure was cancelled the technical guys in the Philippines were not informed, or the information was mislaid.

Looking at the instructions on the charger panel there is obviously a sort of connection between the two systems. Wonder if this panel was the actual one in 1941 - or a later version.

Fred