P-39/P-63 in VVS service (Kurland front)

[greybeard]

I wonder what subtypes of P-39 were in use and actual number of P-63 on the Kurland front from mid 1944 to war's end.

In addition, it looks most of them had their wing guns removed; is it possible to establish how many of them (a percentage)?

Thanks for any info,
GB

 

[greybeard]

About wing guns removal, today I found HERE :

"There is often mentioned that Soviets removed the wing machine guns to improve roll rate by reducing rotational inertia. However, it seems that "removing wing guns" was mainly about gun pods."

follow interesting photos, showing as the .30 machine guns wing armament was retained.

The assertion looks backed by Russian pilot memoirs:

seemingly speaking of a P-39Q.

There's photographical evidence of this practice:

although not always followed:

At this point, I wonder if ANY (or, at least, how many) P-39N had really their wing guns removed (as well as how many P-39Q did retain them...).

Cheers,
GB

 

[gjs238]

What do the German reports says about the Soviet P-39's and P-63's?

 

[greybeard]

What do the German reports says about the Soviet P-39's and P-63's?

That many of the Soviet "P-39" were actually P-63. Don't know about armament...

 

[BiffF15]

Why does the one have a four bladed prop?

 

[tomo pauk]

The bigger prop should provide more thrust for same HP. The bigger prop there is also 4-bladed, vs. 3-bladed for most of the P-39s.

 

[greybeard]

Why does the one have a four bladed prop?

Should be a P-39D-21 or -25... (These were the only two production batches having a 4-blade prop; reverted to 3-blade prop from next batch P-39D-30 since causing loss of directional stability).

 

[BiffF15]

Excellent info! Did not know the P-39 came with the four bladed prop in any variant! The greater thrust is evident in the Mustang and P-63 by increasingly larger vertical tails!

 

[greybeard]

Propeller converts power into thrust. This is made with a certain efficiency. As a general rule: more blades = less efficiency. But also peripheral speed matters: when it gets transonic, efficiency drops. So may be better to increase number of blades and reduce speed.

 

[michaelmaltby]

Deconstruction of salvaged Soviet P-39Q .... photos

P-39Q Airacobra, page 1

 

[Old Wizard]

 

[GregP]

If you add too much horsepower coupled with the 4-blade prop, you destabilize completely due to the added of forward area without an accompanying addition in tail area. Mike Carroll found out when he had a fatal crash in a P-39 with a souped-up engine and P-63 4-bladed prop. It was unflyable under complete control but managed to take off.

The P-63 was larger, with a longer rudder arm. That made the difference.

 

[Capt. Vick]

What is the attachment on the rear of the last photo? Glider tug? Anti-spin parachute mount? Anyone know?

 

[bobbysocks]

for towing targets???? NO its a selfie stick!!

 

[Capt. Vick]

A-ha!

 

[kool kitty89]

Should be a P-39D-21 or -25... (These were the only two production batches having a 4-blade prop; reverted to 3-blade prop from next batch P-39D-30 since causing loss of directional stability).

That would be P-39Q not D, going by Joe Bougher's site:
Bell P-39Q Airacobra

P-39Q-20-BE (Model 26Q-20): The underwing 0.50-inch machine gun pods were sometimes omitted in this version.

P-39Q-21-BE: Similar to P-39Q-20, but a four-bladed Aeroproducts propeller was fitted.

P-39Q-25-BE (Model 26Q-25): Similar to the Q-21 but with a reinforced aft-fuselage and horizontal stabilizer structure and a four-bladed Aeroproducts propeller. The wing guns were deleted from these aircraft, which were exported to the Soviet Union. 700 were built.

P-39Q-30-BE: Tests indicated that directional stability was materially worsened by the four-bladed propeller, and this version reverted to the three-bladed unit. This was the last production version of the P-39Q.

Also note the mention of wing guns being omitted at the manufacturer.


I believe the Soviets also often removed the .30 cal wing guns from earlier P-39 models to save weight. (and preferred the centerline armament in general along with .30 caliber ammunition being rather light -I assume it was more useful for strafing certain soft targets in US use as a ground-pounder, possibly also more useful against some Japanese aircraft though increasingly less so late-war; in US use the ammunition load at least appears to have been greatly reduced in service, with the 1000 RPG capacity almost never used, and loads as low as 300 RPG noted as standard in some documents, which would mean shorter firing time than the .50 cal nose guns)

 

[fubar57]

What is the attachment on the rear of the last photo? Glider tug? Anti-spin parachute mount? Anyone know?

Found this online...

I've tried to translate it but Google Translate went full retard. I don't think anything there spells "selfie". Wojtek..............................?

Geo