Change a plane

[Lindseyman]

The MB3 gets the Griffon that Martin Baker wanted rather than a Sabre (why did the Air Ministry love this engine so?). It flies rings around the Spits, Warhawks,Mustangs and Thunderbolts and gets put into production although mainly used in the Med and far east.
Put Merlins into the TwinMustang?

 

[JudgeKing]

Ok, TSR2, go with it but as a Buccaneer variant, one of the advanced proposals, so that way it ends up doable and as a result perhaps we even see CVA01 continued with and supersonic Buccy ends up in use instead of Phantom....

The CVA-01 would still need an air superiority fighter so the Vickers-Supermarine Type 583 could enter service as well.

 

[Delta Force]

How easily could the tail engine on the TriStar be replaced with a PW4000 or an RR Trent compared to the MD-11, though? The S-duct makes that somewhat more difficult than on-wing engines or the "straight through" trijet layout McDonnell Douglas opted for.

It seems like it would be harder to do than with the DC-10 series. When Rolls-Royce started having issues Lockheed thought it would be easier to have Orenda or another company take over the project. Of course the major selling point of the TriStar was its superior engines, and when they were eventually offered for the DC-10 (to British Airways, the offer was not taken up) the major selling point became safety. If TriStar does well enough a new engine or variant can be developed specifically for it, or it can do the unusual solution of having two different engines (some Boeing 727 conversions use MD-80 engines on the outer pylons and leave the S-duct engine alone).

Plus, ETOPS would likely still happen eventually, and I'm sure someone is going to knock it out of the park eventually with a big twin, as Boeing did with the 777 and Airbus did with the A330.

I wasn't talking about the widebody twins, I was talking about the less direct routes that must be flown by airlines to remain within ETOPS distance of airports. Major investments in Russian airports and ATC had to be made to prepare suitable airports and even then things probably won't be optimal until the next generation of ETOPS rated aircraft come out (some of the Airbus and Boeing jets are shooting for over 300 minutes of ETOPS). Even now a modern trijet could still have use for oceanic and polar routes where ETOPS imposes too many restrictions and a quadjet is too big.

And Lockheed doesn't have a family of products to sell and has been out of the airliner business for a few years at this point, which hurts them.

Not that much. Lockheed still sold about half as many TriStars as DC-10s, and that's with engine development problems and the late arrival of international variants. Everything about the 1970s aircraft was new enough that it went back to being anyone's game for a while. There was no commonality with the older aircraft in terms of engines, design, flying certificates, or anything like that. Airline loyalty or preference for a supplier would help out Boeing and Douglas, but there were still plenty of airlines in the 1970s who were getting their first jets and hadn't developed a modern supplier network.

 

[NothingNow]

It's not really an unsuccessful aircraft, but this is one that's been in my head for a while.
Introducing the P-36/Hawk 75A series in 1938 with four Browning .50 caliber MGs (two in the wings and two in the cowl) and a Supercharged 1200hp R-1820 Cyclone (or Supercharged Twin Wasp of the same output.)
It'd be a massive improvement over the initial production run, given it's heavier armament, and it'd be powerful enough to reach a top speed of at least 330mph, with much better performance at altitude (meaning it'd be able to out-maneuver both the Spitfire and Bf 109E.)

Admittedly, only having four .50s would be kinda light armament later in the war, but considering how well Hawk 75As performed in France with four to six 7.5mm guns, it'd be a hell of an improvement, and they'd be more than capable of eating anything the Luftwaffe had at the time alive (As it was, Hawk 75As scored a disproportionately high percentage of all air to air kills during the battle of France.)

If there was a better, faster-firing .50 available, with a rate of fire comparable to the ShKAS (so ~1,600 rounds/min synchronized,) I'd also want to drop the wing guns, and take advantage of the P-36's almost obscenely low rotational inertia to make the thing the ultimate dog-fighter.

A further, somewhat insane modification could be fitting a modified P-36/Hawk 75 with a Bristol Hercules VI (in it's 1,650hp supercharged glory) and an empennage modified to balance out the engine and additional torque. Again using a constant speed propeller for improved efficiency and performance, as was standard on the initial P-36/Hawk 75.

 

[Simon]

British Overseas Airways Corporation (BOAC) gets wind of how flimsy the de Havilland Comet could be becoming and put their foot down, insisting that it is instead manufactured exactly to the original specification or they won't be buying any. The original thicker metal gauge skin is used, drill riveting and gluing in construction, slightly smaller more rounded windows and Rolls-Royce engines instead of De Havilland's own ones. Net result is that it comes into service a little later but doesn't suffer the disastrous crashes which marred both its and the company's reputations and left the market to Boeing and Douglas.

Æsir has already mentioned building the de Havilland DH, later Hawker Siddeley HS, 121 Trident to the original larger specification with more seating to become a serious competitor to the Boeing 727.

The TSR-2 was never going to get off the drawing board at worst and past the prototype at best. It is like us buying the F-22, never going to happen.

When the decision was made to cancel the project the first prototype was already flying, a second had just completed engine ground tests and was about to take its first flight on the afternoon that the budget announcement was made, looks as though three more airframes had been completed and another three were at various stages of production. These were the development batch so that the different systems could be tested concurrently and there wouldn't be any serious delays if there were any major accidents. If you consider how much money had already been spent, how much was then spent on the F-111 only for the UK to back out and lose shed-loads of money whilst gaining nothing I could see TSR-2 certainly continuing to completion. Now I don't think they would have received the numbers they were originally talking about or it becoming the all-singing all-dancing wonder weapon it's sometimes made out to be, but it would have probably been a respectable aircraft.

 

[Lindseyman]

Short Stirling

Yes I know many were built and that they were moderately successful but what if somebody at the Ministry had realised that designing a bomber to fit the hanger wasn't such a good idea. Shorts are therefore able to design a sensible set of wings and undercarriage for the Stirling. At the same time they redesign the bomb bay so it isn't split up into sections. The RAF get a much more successful bomber and quite possibly there is now no need for the Lancaster. ( They did do this in OTL together with 4 Centauri instead of Hercules but that was a response to the Lancaster and the powers that be didn't want the Stirling production line interrupted even though they accepted that this was a much better design!!!!!)

 

[AdA]

Su15bis with the intended R25 engines but with the lookdown/shoot down radar of the MiG23ML and the wing root NR30 guns of the Su17. R23 and R60 missiles as in the MiG23ML.

 

[Simon]

Another one would be to smack whoever designed the Bristol Belvedere helicopter over the head and get him to realise that it would be a better idea to stick everything outside of the main cabin in fairings. Engines, power transfer to the forward rotor, landing gear, batteries, fuel tanks etc. This gets you something nearer to the American Boeing Vertol CH-47 Chinook, still won't be as good but it will be much better than the aircraft they were stuck using and bridge the gap until the Chinook is finally ordered as a replacement.

 

[Just Leo]

It's not really an unsuccessful aircraft, but this is one that's been in my head for a while.
Introducing the P-36/Hawk 75A series in 1938 with four Browning .50 caliber MGs (two in the wings and two in the cowl) and a Supercharged 1200hp R-1820 Cyclone (or Supercharged Twin Wasp of the same output.)
It'd be a massive improvement over the initial production run, given it's heavier armament, and it'd be powerful enough to reach a top speed of at least 330mph, with much better performance at altitude (meaning it'd be able to out-maneuver both the Spitfire and Bf 109E.)

Admittedly, only having four .50s would be kinda light armament later in the war, but considering how well Hawk 75As performed in France with four to six 7.5mm guns, it'd be a hell of an improvement, and they'd be more than capable of eating anything the Luftwaffe had at the time alive (As it was, Hawk 75As scored a disproportionately high percentage of all air to air kills during the battle of France.)

If there was a better, faster-firing .50 available, with a rate of fire comparable to the ShKAS (so ~1,600 rounds/min synchronized,) I'd also want to drop the wing guns, and take advantage of the P-36's almost obscenely low rotational inertia to make the thing the ultimate dog-fighter.

A further, somewhat insane modification could be fitting a modified P-36/Hawk 75 with a Bristol Hercules VI (in it's 1,650hp supercharged glory) and an empennage modified to balance out the engine and additional torque. Again using a constant speed propeller for improved efficiency and performance, as was standard on the initial P-36/Hawk 75.

The Curtiss Hawk 75 suffered for being introduced for production at a period of time when 2 engine manufacturers were competing for orders by designing engines of better power, while the USAAC was convinced that liquid-cooled engines were where it's at. The R-1820 was a 9 cyl single-row with a diameter over 54", while the R-1830 was a 14 cyl two-row just over 48" around. Since nobody knew ahead of time which engine was the best, the Hawk 75, like the F4F, was designed to take either, which means that neither installation was optimum. Improved performance could have been achieved by designing an installation as accomplished for the final variant of the XP-42, which reached 340 mph with an otherwise standard P-36. The ultimate performance by a P&W R-1830, rated at 1,065 hp, was achieved by the FFVS J-22, but the important factor was not that it was achieved but when it was achieved. With the advent of the R-2800 engine, it all becomes moot. The possibility of improving radial engine-powered fighter performance by means of improved nose aerodynamics didn't seem very important in war-time America although it was addressed post-war by every unlimited-class air racer. I suspect that the revolutionary FW-190 would have been just another failed type with an American-style nose.

 

[NothingNow]

The Curtiss Hawk 75 suffered for being introduced for production at a period of time when 2 engine manufacturers were competing for orders by designing engines of better power, while the USAAC was convinced that liquid-cooled engines were where it's at. The R-1820 was a 9 cyl single-row with a diameter over 54", while the R-1830 was a 14 cyl two-row just over 48" around. Since nobody knew ahead of time which engine was the best, the Hawk 75, like the F4F, was designed to take either, which means that neither installation was optimum. Improved performance could have been achieved by designing an installation as accomplished for the final variant of the XP-42, which reached 340 mph with an otherwise standard P-36. The ultimate performance by a P&W R-1830, rated at 1,065 hp, was achieved by the FFVS J-22, but the important factor was not that it was achieved but when it was achieved. With the advent of the R-2800 engine, it all becomes moot. The possibility of improving radial engine-powered fighter performance by means of improved nose aerodynamics didn't seem very important in war-time America although it was addressed post-war by every unlimited-class air racer. I suspect that the revolutionary FW-190 would have been just another failed type with an American-style nose.

Yeah, optimizing the engine mounting seems like a no-brainer really. Same with minimizing the rotational inertia, although American and British designs seemed hellbent on doing things the hard way in the name of firepower.

(Never mind that having to line up a target in the convergence of the guns, instead of having everything close to the centreline is quite limiting in itself.)