Favorite plane never built (or perhaps as a prototype).

[BarnOwlLover]

This thread is pretty simple (and I hope this one is in the right or right-ish place). This is about aircraft or versions of aircraft that were never built, or maybe only existed in prototype form (I'll allow that).

The XP-51F/G Mustang are among the prototypes that are my favorites, as well as the NA-117 (early P-51H design, built as a mock up). But as far as projects that didn't get built, North American's "Packard Pursuit" is one of them. Detailed in the book "P-51B: NAA's Bastard Stepchild", it was a paper design based on early thoughts on a Merlin Mustang before the XP-78/XP-51B was fully designed. It has the "A6M" type canopy that drgondog has referred to in the past as a design study before the P-51D's definitive bubble canopy got made. Though it was a stepping stone to the Merlin P-51s, the Packard Pursuit looked the business for 1942 and pointed the direction of the P-51's evolution.

Also from the book "P-51B: NAA's Bastard Stepchild", was various mock ups for cannon armament for the A-36 and P-51/P-51A. These included mock ups for 4 20mm cannons and 4 37mm cannons, the latter in underwing pods. If you haven't seen it in the book, all of them, namely the 37mm cannons, were some serious stuff for the time.

 

[Shortround6]

For some reason somebody or several somebodies, were enamored with the 37mm cannon, or the idea of a 37mm cannon since the US 37mm aircraft cannon wasn't all that good.

Now there may have been problems with what was promised vs what was delivered.
The as issued M4 37mm cannon was rather greedy with volume.

The Horseshoe feed stuck around until well through P-63 production. The P-63A-10 got the M10 gun with a more conventional belt feed. Also increased the ammo capacity from 30 rounds to 58. The M10 gun could also be feed from either side.
There were some significant problems with using the 37mm cannon and .50 cal machine guns in the same plane unless you were firing at rather close ranges,

There was also an attempt to scale the gun up to use the 37mm tank/anti-tank ammo but the weight ballooned up to just over 400lbs for the gun so you need a pretty hefty airplane to carry more than one.
Wing mounted guns would have to wait for the belt version and how long that took to show up after it was promised is a real question.

 

[SaparotRob]

XB-70.

 

[BarnOwlLover]

The cannons on the Mustang were I believe intended to be ground strafing weapons for the A-36 (though being fairly low velocity shells, there use on anything more than lighter tanks would probably be dubious unless attacking from above), and in that instance were to be belt fed, per drgondog's book. I haven't read that part yet in great detail, but I'd assume that NAA would've developed their own belt feed system, just as they developed their own mounting for the 4 20mm cannons.

IMO, 20mm would've been a better bet, especially air to air.

 

[Alan Stevens]

XB-70

The North American Aviation XB-70 Valkyrie is a retired prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bomber for the United States Air Force Strategic Air Command.

Designed in the late 1950s by North American Aviation (NAA) to replace the aging B-52 Stratofortress and B-58 Hustler, the six-engined, delta-winged Valkyrie could cruise for thousands of miles at Mach 3+ while flying at 70,000 feet (21,000 m).

 

[SaparotRob]

XB-70

The North American Aviation XB-70 Valkyrie is a retired prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bomber for the United States Air Force Strategic Air Command.

Designed in the late 1950s by North American Aviation (NAA) to replace the aging B-52 Stratofortress and B-58 Hustler, the six-engined, delta-winged Valkyrie[2] could cruise for thousands of miles at Mach 3+ while flying at 70,000 feet (21,000 m).

And look good doing it.

 

[BarnOwlLover]

In honesty, I wanted this to be mostly about World War II era aircraft, but I guess that this could be all eras aircraft.

Here's some images by the CARPA R30 and 40. Built by the predecessor to Matra:

CAPRA/MATRA Projects

an aircraft of a designer whose name is F. Capra, to be honest, until yesterday i didn´t know this company existed. But it seems he offered some designs to the french government before the war, but they never bought them, later Capra emigrated to USA where he worked for Lockheed. The Capra...

www.secretprojects.co.uk

 

[Sabrejet]

SARO SR.177 would be one: I'd love to know what that would have looked like in service.

Also one obvious "if only" - the Miles M.52. That aircraft could easily have reached Mach 1 before the Bell XS-1. Shoulda coulda.

And another obvious one: the TSR.2. Another world-beater in the same vein as the XB-70/RS-70 and Avro Arrow (the latter being a fourth!)

 

[SaparotRob]

In honesty, I wanted this to be mostly about World War II era aircraft, but I guess that this could be all eras aircraft.

Here's some images by the CARPA R30 and 40. Built by the predecessor to Matra:

CAPRA/MATRA Projects

an aircraft of a designer whose name is F. Capra, to be honest, until yesterday i didn´t know this company existed. But it seems he offered some designs to the french government before the war, but they never bought them, later Capra emigrated to USA where he worked for Lockheed. The Capra...

www.secretprojects.co.uk

Enough cool inter-war, radial engined, low winged, tail dragging monoplanes got made to keep me entertained, except in too low numbers. The planes I like were built in numbers that disqualify them from the thread. Although, perhaps the XP-47G-J?
I guess I'm a bomber fan. Ya' know, bring your friends along. That's why I thought of the Valkyrie...and now the Republic Rainbow.

 

[special ed]

Fletcher FL-2

 

[A4K]

BAC TSR.2.

 

[fubar57]

The Arrow of course

 

[Warspite63]

Martin-Baker MB-5. If only....

 

[Sabrejet]

Every time I look at a TSR.2 I am reminded of the massive amount of effort that was put into this programme by the good men and women of our once-glorious aircraft industry. We are lucky that some survive; when I was in training at Halton we had a lot of other TSR.2 parts to learn on too. As young men those items were like the holy grail. Hard too to imagine that if it had gone into service, the wonderful thing would now be retired and replaced by something maybe even better.

 

[A4K]

She was one awesome bird alright.

 

[NevadaK]

Vought XF5U Flying Flapjack

If you want a jet - Vought F8U-3 Crusader III

I came across a couple NACA Documents regarding wind tunnel testing of the F5U. As a non-engineer there's a lot that is out of my comprehension, but I thought some of our more learned members of the community might get something from it. It's too bad that there weren't compact turboprops available at the time that could have been located at the tips immediately behind the propellors. It would have eliminated the complicated drive shaft system and the associate weight and power loss penalties.

 

[ThomasP]

For modern the F-23 'Black Widow'.

For post-WWII the Northrop B-35 flying wing.

For WWII era the folding wing SeaHurricane.

 

[muskeg13]

Ditto on the B-35 Flying Wing, but for late war deployment in the Pacific where its range and payload would exceed that of the B-29. Initial contracts specified late 1943 delivery of the first prototype. WW2 B-35 production might have been possible if this project had a higher priority, perhaps to augment and be the immediate successor of the B-29 with the B-32 cancelled?

However, my other favorite that never made it into full production is the Republic XF-12 Rainbow. Republic XF-12 Rainbow - Wikipedia

 

[Admiral Beez]

Gloster F5/34. Build it under license in Canada or India, or Australia, using a P&W or Curtiss radial. If Gloster's new owners Hawker-Siddeley don't want to build it, sell the design and drawings to CCF, HAL or CAC.

 

[MIflyer]

A fine companion to the XR-12 Rainbow was the beautiful and very impressive XP-72. In production it likely would have been built with P-47N wings.