North American F-82 Twin Mustang | Hacker News Reader

North American F-82 Twin Mustang

en.wikipedia.org

69 pointsTomte54 comments

I created this entry. It's evolved considerably.

I do still recommend the original source I used: The Concise Guide to American Aircraft of World War II by David Mondey. It's great.

The wikipedia entry seems to evade the most blaring question that popped into my mind: why the 2 cockpits? After a bit of reading it dawned that because this was intended as a very long range fighter, there were 2 pilots to share the flying duties as flight time might be anywhere up to 12 hours in duration (intended range of 2,000 miles, cruising speed of 286 mph).

The later night fighter model ditched the 2 separate controls and had a pilot in the left cockpit with a radar operator sitting in the right cockpit.

Edit: The next question that I had was: Why not a single cockpit with 2 seats? I'm guessing if factories were already tooled up to produce Mustang fuselages then it could be produced with a quicker "time to market" so-to-speak?

The page says fuselage was extended to add more room for fuel so it doesn't look like there was room to add a second seat, at least, not without having to make two very different fuselages.

Googling about, it seems like regular P51 two-seat conversions were done by reducing fuel capacity as well.

1. Dual cockpits were a result of slapping a couple 51 bodies together, already mostly engineered.

2. Kept it because it worked for longer missions using dual controls.

3. Saves money in production, tooling, and engineering to just use existing designs where possible. Same parts are already set up, just run the process another time.

4. Symmetry man.

There's an interesting CS analogy in that aircraft fuselage are extremely tightly coupled making changes difficult. Imagine making an existing plane a foot longer. Well that means you'll need a slightly larger wire to carry the current for the landing lights over a longer distance so thats heavier which requires a larger hole thru the bulkhead which is now too light so you put a strengthening plate on it which makes the auxiliary oil cooler not fit, meanwhile its now too heavy for the original landing gear to handle the weight ... eventually 100000 engineer hours later you have a slightly larger plane. It would have been cheaper to just design a new plane from the ground up...

Wings are not as tightly coupled as fuselage systems. Almost plastic model like, you can chop off the ends of two planes wings and stick them together. Its not quite that simple, but at least it doesn't involve redesigning the oil cooling system.

Some software is extremely tightly coupled like an aircraft fuselage, some less tightly coupled like an aircraft wing.

Not to disagree with your main point that there's a lot of tight coupling ... but planes are regularly stretched[1][2] so it seems like it's still a lot simpler than designing a whole new plane from scratch. Even new designs are really evolutions of old planes.

[1] https://en.wikipedia.org/wiki/Airbus_A340#Variants

[2] https://en.wikipedia.org/wiki/Boeing_747#Variants

Probably a better example from the opposite end of the spectrum would be the design changes between the F/A-18C/D and the F/A-18E/F. The initial plans were to stretch the C/D model to add fuel and improve the abysmal range, but this increased weight which required larger wings which required all sorts of major design changes. In the end, the E/F ended up with only 40% parts commonality, and was now a medium weigh fighter like the F-15, rather than the cheap light fighter like the F-16 it began life as. Engineers I know who worked on the E/F design have told me it would arguably have been cheaper to design a new plane from scratch, but the Navy was so afraid of another failed project that they were only able to sell it to the Navy as an "upgrade" of a plane design they already had. Dubious in an engineering sense, but absolute genius in marketing.

> but planes are regularly stretched[1][2]

One of the main design requirements for those plane models was, right from the start, to support multiple variants by adopting a modular design.

Yet, they are still very tightly coupled.

In fact, IIRC the Airbus A340 project is widely known for having experienced a billion-euro delay due to production problems caused by CAD software issues. In short, if my memory doesn't fail me, some design teams used Catia V4 while others migrated to Catia V5, whose CAD engine was rewritten from scratch. Consequently, some slight differences in how the different versions handled geometry definitions resulted in some electric cables designed by some engineering teams to be incompatible with the structural layout designed by other engineering teams. We're talking about differences in centimeters in a plane with a wingspan with around 56m.

An F-82 fuselage is literally a longer P-51H fuselage:

> North American Design Chief Edgar Schmued incorporated two P-51H Mustang fuselages lengthened by the addition of a 57 in (145 cm) fuselage plug located behind the cockpit where additional fuel tanks and equipment could be installed.

Yes, things are coupled, but they are still malleable. The F-82 fuselage was longer than a normal P-51 fuselage by almost 5' (57 inches). They stretched the section behind the cockpit, to give it more room for fuel tanks.

Meh, symmetry is an engineering cop-out; much more fun is https://en.m.wikipedia.org/wiki/Blohm_%26_Voss_BV_141 :)

See also the Rutan Boomerang: https://en.wikipedia.org/wiki/Rutan_Boomerang

The Bf-109Z, which never flew, was the same kind of idea as the F-82 but only had one cockpit (on the left side), for that same sort of asymmetry.

So it's a hack, basically. An improvised solution that exploits the shortest path to getting something done rather than taking extra time to do it the "right" way.

The question that jumped out at me was, why this and not the P38: https://en.m.wikipedia.org/wiki/Lockheed_P-38_Lightning

It's like this was just slapped together with spare parts, while the p38 could have been upgraded with better engines.

While F-82 and P-38 shared the exact same engine, the F-82 had higher top speed, higher cruising speed, longer range, and could carrying 1500lbs more at take off. Apart from ceiling high, the F-82 beat the P-38 in almost every measure.

It was also based on the legendary P-51 which remained in service into the 50s, where as aircraft like the P-38 were immediately drawn down after the war.

Yeah, the P-38 was a decent design, but it's very much a 1930's era plane with its oval pattern wings and control surfaces. The P-51, despite technically only be a couple years newer than the P-38, incorporated a LOT of improvements, most notably those in the 1940 NACA study data. The laminar flow wing alone pushed the P-51 well beyond anything else produced previously. The P-51 was arguably the first line fighter to be designed with aerodynamics based on hard science, rather than seat of the pants "this seemed to work before" design practices.

The operating manual: https://books.google.com/books?id=UggPCtYPyQ8C&printsec=fron...

The Hawker Sea Fury, another prop driven fighter, did managed to successfully take on jet powered MiGs in Korea:

https://en.wikipedia.org/wiki/Hawker_Sea_Fury

Your comment made me wonder: if nowadays air battles are being decided based on stealth, long-range sensors and long-range AA missiles, why aren't we seeing a resurgence of cheap prop planes such as the Hawker Fury?

I mean, the price of a single F22 Raptor is speculated to be around $180M, while the price of a single Hawker Fury was established to be around $55k.

Although a F22 may dominate all technical criteria, it loses heavily on cost and the amount of resources that need to be spent to get one up and running.

Moreover, it appears that the cost of building a single F22 is enough to build, maintain, man and train a hefty number of complete squadrons, which could also be equipped with the same long-range sensors and weaponry.

That's what modern drone aircraft are.

They cost more than 55k because of inflation, but also because the sensor systems satellite uplink etc are a large chunk of the overall costs. Still at 4Million a pop the MQ-1 Predator's are cheap. https://en.m.wikipedia.org/wiki/General_Atomics_MQ-1_Predato...

It's successor is 16 million but it's larger and "An MQ-9 with two 1,000 pounds (450 kg) external fuel tanks and one thousand pounds of munitions has an endurance of 42 hours."

    at 4Million a pop the MQ-1 Predator's are cheap

Less than the pilot alone: https://www.quora.com/How-much-does-it-cost-to-train-a-fight...

We are seeing a resurgence of prop planes, but only for low-intensity roles. [1] However, low and slow planes are vulnerable to cheap MANPADs [2], and in the event of a near-peer conflict (ie, US vs China), they simply can't operate on the front lines. A ~$600,000 Sidewinder from an F-22 can shoot one down with ease, but a cheap prop plane simply doesn't have the sensors for shooting back.

[1] https://en.wikipedia.org/wiki/Embraer_EMB_314_Super_Tucano [2] https://en.wikipedia.org/wiki/Man-portable_air-defense_syste...

Yes, aside from unpiloted aircraft, there is a current Air Force project/competition for a prop driven light attack aircraft. One of the competitors is a crop duster conversion.

You have to have some sort of admiration for something called an "Air Tractor" (http://802u.com/).

Among other things, you still need speed, even with long-range weapons. And speed is expensive, once you get into supersonic and beyond, you need special materials etc etc

I don't think a Fury, even a hypothetical one that's been modified with modern sensors and weapons, would ever prevail against an F-22.

Let's say you put identical missiles on both. Once in range, both fire. The F-22 can then turn around and get back out of range before it's hit. The Fury is essentially motionless, and will be shot down. Repeat ad infinitum.

Sure, but you can afford to field 2,700 Furies against that F-22, which will quickly run out of ammo and return to base, while the remaining 2,690 Furies are running around machine gunning your ground troops. (Sure, this is a bit contrived... but even 100-to-1 probably still makes sense. Iran's already taking this sort of low-cost approach with small speedboats intended to go up against US aircraft carriers.)

>you can afford to field 2,700 Furies against that F-22

You can't just divide the cost of a Fury into the cost of an F-22 and assume that's even remotely reasonable as a fieldable proportion. The limiting factor isn't the cost of building the planes, it's the logistics of coming up with with enough fuel, pilots, maintenance, and ground facilities to keep them flying. There's nobody who couldn't afford something better that could afford to field maybe 3:1 vs the F-22.

The salesman for Burt Rutan's little gun-armed midget ARES fighter/attack plane liked to tell people to "imagine how the Falklands War would have been different" if the British Harriers had been faced with waves of hundreds of ARES planes.... completely failing to address the fact that Argentina couldn't possibly train enough qualified pilots to sit in those hundreds of cockpits.

Hence my statement that it's a bit of a contrived example.

Fuel's relatively cheap for a prop plane, one pilot would manage more than one drone aircraft at once, maintenance is dramatically easier and cheaper on a prop plane, etc.

The F-22 can go out, shoot a bunch down, return, go out again, shoot a bunch more down, and keep on going. With a more realistic ratio, it looks pretty bad for the Furies.

> The F-22 can then turn around and get back out of range before it's hit. The Fury

Why are you assuming that a hypothetical 1-on-1 scenario is the only feasible scenario? If an operator can man half a dozen of fury squadrons for the same cost that an operator is able to afford a single F22, why would you assume that they would put up a single fury to counter a F22?

And let's assume that a wave of furys managed to down a F22. Now what? Will the operator of the F22 spend an additional $180M to churn out a single unit? Because for the same cost, the opponent can churn out 100-fold units. Is this sustainable?

I don't think it really assumes 1-on-1. "And let's assume that a wave of furys managed to down a F22." Let's not. I don't see how that could happen. No quantity of Furies would be able to shoot one down. The F-22 will just keep picking them off until it runs out of ammo or targets. If the former, it'll return to base, rearm, and keep going.

Something other people haven't brought up but I think is important:

Military aviation is still in the exponential part of the technology S curve. Each new generation isn't just a little better than the previous one, it is massively better and embodies some new piece of technology the previous generation is nearly helpless against. The Fury is multiple such technology leaps out of date, and as a result is basically helpless in the sky.

Consider:

The Sea Fury has a maximum takeoff weight of 6,600 kg. The F-22 has a maximum takeoff weight of 38,000 kg. How do you take a plane like the Sea Fury, and let it carry 6 times the weapons/sensors/gadgets? A revolution in engine technology.

The Sea Fury's skin is made from duralumin, and sticks out like a sore thumb on radar. The F22's skin is made of a composite material that makes it nearly invisible to radar. How do you take a plane like the Sea Fury, and let it operate with impunity against radar? A revolution in materials technology.

And so on and so on. The F22 embodies something like five separate revolutionary technologies, any one of which would enable it to defeat nearly unlimited numbers of Furys. But all put together and it's - well, the Furys become so outdated they're almost not even worth killing.

Unlimited? It doesn't carry the stores. At 10:1 the F22 would have to watch helplessly as a few of them slipped through. What's it going to do, ram them?

Worse with the F35 which has no gun and can only carry 2 missiles without losing stealth.

>Unlimited? It doesn't carry the stores.

The F22 is nearly 2000 km/h faster than the Sea Fury, and the turn around time is said to be on the order of 20 minutes. In the time it takes the Sea Furys to go to the target, do their business, and go home you're looking at 3+ F22 sorties each hitting a nearly guaranteed 12 kills (maximum anti-air missile load with twinning racks) plus however many they can kill with 480 rounds of 20mm cannon fire.

So yes, damn near unlimited. That's what happens when the enemy can kill a dozen pilots every 20 minutes with no fear of retaliation. You get a bloodbath.

>Worse with the F35 which has no gun and can only carry 2 missiles without losing stealth.

Why do people who know nothing about planes instantly forget that fact the moment the F-35 is brought up?

The F-35A does have a cannon, while the F-35B and C have the option for an external cannon pod. The F-35 can carry four missiles in its internal bays, not two.

turn around time is said to be on the order of 20 minutes

And for how many sorties can it sustain that? Even if you had enough F22 pilots to keep it going...

Send just enough Sea Furies to force the F22s to scramble until they are forced into deep maintenance - then waltz in with your main force, game over.

I don't think you can multiply costs like that. The expenses of maintaining the logistics for that many planes would be exorbitant, and I believe the unit costs of modern aircraft would be far lower if we made more of them.

If you're looking for more weird aircraft try https://www.reddit.com/r/WeirdWings/top/

http://www.fiddlersgreen.net/aircraft/North-American-P82/IMA...

Same concept for a messerschmitt: http://www.airwar.ru/image/i/fww2/bf109z-i.jpg

https://en.wikipedia.org/wiki/Messerschmitt_Bf_109_variants#...

Storm IV Twin-Pod Cloud Car

http://starwars.wikia.com/wiki/Storm_IV_Twin-Pod_cloud_car

Quite a bit of Star Wars took cues from WW2.

Going off on a little tangent here... I always wondered how Lucas came up with some of his weird but convincing fantasy names. It is because many are obscure-ish real names.

Young George Lucas was into cars and World War 2. Aunt Beru: Beru made spark plugs. Planet Hoth: Hoth was a German general.

All of the "red leader" stuff is directly lifted from another film - the Battle of Britain (1969) http://www.imdb.com/title/tt0064072/. Watch the dogfight sequence and see if it doesn't remind you of Star Wars: https://www.youtube.com/watch?v=Sk5gMaCq8GE

Some of the dialogue for the Death Star attack scenes were taken directly from "The Dam Busters", a WWII movie depicting the Allied attack on a heavy water producing German controlled damn that required specialized weapons to be delivered in a highly specific attack run.

The dams didn't have anything to do with the production of heavy water, they just provided power for factories in the Ruhr area.

Ah your right, apologies. I was getting Operation Chastise (an attack by specialized bombers on the Ruhr valley hydroelectric dams and the subject of the movie) confused with Operation Freshman (an attack by commandos on a German controlled dam in Norway that produced heavy water).

The F-82 was a fascinating plane but not that unusual given the P-38 was similar and serial producing right through WWII.

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