P-51 Mustang & F-82 Twin Mustang Proposals and Variants

[GTX]

Hi folks,

A new thread for and unknown, secret or rare North American P-51 Mustang variants. I'll start off by including what may have been the ultimate Mustang:

This was supposedly a proposal that North American had come up with in case the war had continued. As you can see, it had forward swept wings as well as an advanced (specifically how I don't know), a Westinghouse jet engine in the rear fuselage and a tricycle undercarriage.

Regards,

Greg

 

[Michel Van]

i found link to Italian blog
with picture of a Gunpod for F-82

[Gunslingers] F-82 Twin Mustang Gunpod

Il pod sperimentale progettato per aumentare la potenza di fuoco del caccia a lungo raggio North American F-82 Twin Mustang. Esso conteneva 8 mitragliatrici Browning M2 calibro 50, che andavano ad …

sobchak.wordpress.com

after page the pod supply 8 Browning M2 (each with 440 shots, caliber 50)
6 gun in wing 2 under the pod (make in total 14 guns in F-82)

 

[Justo Miranda]

additional info ...

 

[Weasel Pilot]

14 !! .50 caliber BMG...now THAT's an attention step! Wonder how much the aircraft slowed as these were being fired? If memory serves, we lost about 5 kt per second when firing the GPU-5 pods (30mm, same round as A-10's GAU-8) off our F-4Es.

 

[Lauge]

Wonder how much the aircraft slowed as these were being fired? If memory serves, we lost about 5 kt per second when firing the GPU-5 pods (30mm, same round as A-10's GAU-8) off our F-4Es.

No contest! A (probably over-) simplified, back-of-the-envelope calculation shows that:

Force = the time derivative of the impulse.

Impulse = mass X velocity

so

Force (recoil): mass X velocity X rate-of-fire

This ignores the recoil produced by the propellant gasses leaving the barrel together with the projectile (but I said it was simplified ).

So, for the GAU-13 in the GPU-5 pod:

Projectile mass: 15,1 oz (for the API) = 430 g = 0,430 kg
Muzzle velocity: 3.600 ft/sec = 1.030 m/s
rate of fire: 2.400 rds/min = 40 rds/sec

Recoil: 0,430 X 1.030 X 40 = 17.716 N

For 14 Browning M2 .50 cal's:

Projectile mass: 622,5 grains (for the M8 API) = 40,3 g = 0,0403 kg
Muzzle velocity: 3.050 ft/sec = 930 m/s
Rate of fire (per gun): 750 rds/min = 12,5 rds/sec
Rate of fire (combined): 14 X 12,5 = 175 rds/sec

Recoil: 0,0403 X 930 X 175 = 6.558 N

or roughly 1/3 that produced by the GAU-13.

The source for the above data is Wikipedia and Janes Infantry Weapons, 2009 edition.

The above calculation, as stated, ignores the recoil force produced by the propellant gasses (both the extra mass being ejected, as well as the propulsive "rocket" effect of the gas leaving the muzzle), and it tells you little about the "felt" recoil, since the mass of the gun itself is ignored. However, since 14 Browning M2's mass about 530 kg (38 kg pr. gun) and the GAU-13 comes in at 151 kg, "felt" recoil of the GAU-13 (1/3 the mass and 3 times the generated recoil force) should be significantly more than that of the 14 M2's.

There's probably a couple of 30mm-size holes in my calculations, so corrections are welcome (provided they are suitably polite : ).

Regards & all,

Thomas L. Nielsen
Denmark

 

[r16]

ı remember reading the A-10 was getting about 4500 kg of drag through gun . It fired faster at 4200 rpm (?) but are the guns same , do they have the same velocity out of the barrel ?

 

[Lauge]

....do they have the same velocity out of the barrel ?

As I read it, the difference between the GAU-13 (gunpod) and the GAU-8 (in the A10) was the number of barrels. 4 in the GAU-13 vs. 7 in the GAU-8. Muzzle velocity should therefore be the same for the two weapons.

PS, then a drag force of 4.500 kg corresponds to about 45.000 N. Adjusting the calculation above for increased rate of fire (4.200 rds/min instead of 2.400 rds/min) gives a recoil force of 31.000 N. The difference up to the 45.000 N would be due to the over-simplified nature of the calculation, such as ignoring the contribution from the propellant gases*.

Regards & all,

Thomas L. Nielsen
Denmark

*) Actually, I seem to remember reading somewhere (don't as me for a source) that roughly 1/3 of the recoil force from a firearm comes from the ejected propellant gases. Adjusting for this brings us right up to the 45.000 N...... B)

 

[XP67_Moonbat]

Slightly clearer version

 

[Justo Miranda]

Here some additional info ...

 

[Firefly 2]

Probably a dumb question: Where would the .50's go?

This wing doesn't seem to have the required space to store the then standard complement of 6*.50 Browning guns.

 

[frank]

Interesting that the prop was to rotate 'the wrong direction'!

 

[Michel Van]

your sure it a jet engine ?
look more a motorjet (aka thermojet)

there was also a P-51 Ramjet version

fantasic art with P-51 ramjet
http://www.secretprojects.co.uk/forum/index.php/topic,7238.0.html

more on Jet Mustangs
http://www.secretprojects.co.uk/forum/index.php/topic,3637.0.html

F-82 Twin Mustang
http://www.secretprojects.co.uk/forum/index.php/topic,6748.0.html

 

[Tophe]

I have found a Schmued patent of 1944/46 representing the XP-82 Twin-Mustang (at http://www.adventurelounge.com/aircraft/design/087.html and http://www.adventurelounge.com/aircraft/full/design/087.html ) but I am not sure:
- if the canopy is the same as the P-51D/P-82, this would be a tiny Twin-Mustang (left below)
- if the engine/nose is the same as the P-51D/P-82, this would be a Twin-Mustang with giant canopy (right below)
Dimensions or details would help but I do not find the 3 pages patent both at Google Patents and at Espacenet… May someone help me?

 

[Tophe]

The explanation may be the big canopy of the XP-51F/G/J that would have been considered also for the P-82, before prefering the P-51D/H:

 

[CFE]

In the case of the P-82 Twin Mustang, it's important to note that the Twin shared far more in common with the P-51H than the P-51D. The lightweight Mustangs (F/G/J/H and P-82) used a new airfoil shape, new wing planform, and essentially represented an all-new airplane (aside from the powerplant.)

 

[Tophe]

Thanks for this detail, while the canopy size issue remains the same D/H/82-size or F/G/J?

 

[Skyraider3D]

fantasic art with P-51 ramjet
http://www.secretprojects.co.uk/forum/index.php/topic,7238.0.html

Thanks, glad you like it!

Attached a crop of this image but edited to look like an old magazine photo.


Here's an older piece with the same aircraft but with MTO markings. Needless to say it's all fictional.

The aircraft in the background is a Junkers EF 100 transport, dressed up as "Immelmann V"...

 

[mz]

Great work! That postcard is especially well done, as most artificially aged stuff is not convincing at all.

 

[Steve Pace]

Hi folks,

A new thread for and unknown, secret or rare North American P-51 Mustang variants. I'll start off by including what may have been the ultimate Mustang:

This was supposedly a proposal that North American had come up with in case the war had continued. As you can see, it had forward swept wings as well as an advanced (specifically how I don't know), a Westinghouse jet engine in the rear fuselage and a tricycle undercarriage.

Regards,

Greg

Can you send me a high res image of this drawing. Thanks!

Steve Pace

 

[verner]

What did the prototype of this AC look like? Did they attempt splicing two Mustangs together before they went to a new design?

 

[frank]

No. It looked basically like the F-82 was built.

What did the prototype of this AC look like? Did they attempt splicing two Mustangs together before they went to a new design?

 

[verner]

Thanks

 

[Arjen]

North American "mid-engined Mustang"

Original source: not available
Debunking: http://www.secretprojects.co.uk/forum/index.php/topic,5933.msg121649.html#msg121649

In Green's "Fighters" vol 4 p 141 ,there is a photo of the mock-up of a Mustang fitted with a RR Merlin aft of the cockpit : " y " is not a what-if , but a serious project.

I have a copy of William Green's "Fighters" vol 4, will scan image. Real project.
<edit> Found an image here.

<edit>Added William Green's image.

 

[Pepe Rezende]

It's not a Merlin, but a Griffon engine. This was a Rolls Royce testbed.

 

[Arjen]

It's not a Merlin, but a Griffon engine.

Looking at the size of the engine that might well be true. Do you have more information?
I found this here:

The Merlin conversion was very promising, but the director of the Hucknall establishment, Ray Dorey, had an even more ambitious idea. He wanted to mate the Mustang to a Griffon engine, mounted behind the pilot as was the Allison in the Bell P-39 Airacobra. Rolls-Royce engineers believed this aircraft would be capable of a top speed of 800 KPH (500 MPH), but it never progressed beyond the mock-up stage.

This was a Rolls Royce testbed.

William Green's image caption: "The mock-up of Rolls-Royce's proposal to mount a Merlin engine in the Mustang aft of the cockpit."

 

[lark]

Gentlemen,

Try the searchfunction for Rolls Royce FTB Mustang

and /or FTB Mustang...

Good luck.

 

[Justo Miranda]

Additional info...

 

[Arjen]

FTB Mustang topic:
http://www.secretprojects.co.uk/forum/index.php/topic,3440.msg27408.html#msg27408

 

[Stargazer]

I knew about the F.T.B. Mustang project, but I thought the one depicted in the model was different. It uses a P-51B-type fuselage and canopy instead of the later P-51D-type used in your graphics, Justo.

 

[Arjen]

Gentlemen,

Try the searchfunction for Rolls Royce FTB Mustang

and /or FTB Mustang...

Good luck.

Knowing what to look for helps

 

[Orionblamblam]

North American P-82 Twin Mustang cutaway.

Source:
http://sobchak.wordpress.com/page/2/

Now, where have I seen that before? Hmmmm...

http://up-ship.com/blog/?p=6691

Hmmmph.

 

[circle-5]

North American Aviation FSW Mixed Propulsion P-51 Mustang (proposed) factory model.

 

[jimbrooks]

Fascinating. What books describe the forward-swept P-51 prototype or other prototypes?

I have found one paragraph in Mustang Designer: Edgar Schmued and the P-51, Ray Wagner.
This book does have 1 or 2 pages of details and pictures about a rocket-powered P-51.
IIRC, North American F-86 Sabre Owners' Workshop Manual mentions advanced P-51 prototypes
before those evolved into the FJ/F-86.

I've been collection information about the exotic variants of the P-51 Mustang here:
http://www.jimbrooks.org/web/aviation/info_P-51Mustang.php
(comments welcome)

 

[fightingirish]

Re: Mustang Variants / North American D-118

North American D-118

A North American Aviation concept for a highly modified P-82, dating from 1949. The piston engines would be removed and replaced with Allison XT-38 turboprops. The engines would be located mid-fuselage, necessitating that the cockpit would have to be moved well forward of their normal position. The end result would be a plane that weighed the same, gave the pilots better views and went substantially faster.
This one may show up in a future issue of USBP, as the intended role was ground attack.

Link: http://www.aerospaceprojectsreview.com/blog/?p=1537


Nice find, Orionblamblam! B)

 

[Stargazer]

Great!

 

[Skyraider3D]

Pretty cool! B)

 

[Jemiba]

Not a 3-view, rather a very basic general arrangement drawing:

 

[Stargazer]

Not a 3-view, rather a very basic general arrangement drawing:

Thanks, Jens. I almost did one myself but thought I was lacking some solid reference for the XT38 in that configuration.

 

[Jemiba]

There's no solid reference, of course, just that artist impression !
As the engine was to be positioned in the mid fuselage, there would have been hardly
much impact on the shape of fuselage, besides the repositioned cockpit and the deletion of
the belly scoop, I think. At least that's my interpretation of the drawing and of what seems
to be an intake directly in the nose, but I admit, that it would be appropriate to the "Theoritical
and Speculative" section, too.

 

[Orionblamblam]

There's no solid reference, of course, just that artist impression !

Not true. There are two three-views, one detailed inboard profile, one overview of removable panels...