WWII aircraft armament machine guns and cannon

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Another masterful job of wrapping a small airframe around a monster engine is the F8F Bearcat.

Climb to altitude was faster than the early generation of jet fighters. Probably the ultimate carrier based piston engine interceptor.

A small fighter (relatively speaking) so significant numbers could operate off the escort carriers, too few in numbers and too late in the war for them to have a significant effect, but a masterpiece of compact design, though I heard it was a bit of a maint nightmare because of how closely packed the systems around the engine were.

There's no free lunch!

[Pumpkin]

Yes sir,
Lucky for our enemies it arrived after the conflicts were over.
Also had… 20mm Cannons.

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Most of the Bearcats built were armed with .50 cal machine guns. The rest had 4x 20mm cannons. Except for about 60 recon versions armed with two 20mm cannon.

both the .50s and the 20s were more than adequate to knock down any enemy the Bearcats ever faced.

[davidsog]

that the ergonomic benefits of cockpit size was less by intent than by serendipity.

It was definitely by intent. It is one of the considerations when trying to wrap the smallest amount of airplane around the largest engine possible swinging the biggest propeller you can fit. One of these compromises is considering how long a pilot will have to sit in that cockpit.

Even the massive P-47 followed this formula. The turbocharger technology of day dictated that any turbocharger for the R-2800 would have to be a massive piece of kit. In fact, that turbocharger adds some 900lbs to the weight of the aircraft.





The P47 cockpit could have been much smaller. In the design intent for a fighter that could escort the new generation of turbocharged high altitude bombers on the drawing board contemporary to the P47. The P47 was supposed to be the escort for the B-29 at high altitudes and long distances.

In terms of subsonic aerodynamics, the WWII guys were at the pinnacle of our knowledge and engineering.

The frontiers of aircraft design were compressible aerodynamics as well as Stability and Control science.

[Pumpkin]

Were the P-38 and P47 cockpits quieter than the supercharger equipped fighters?
I would think they would have been by a significant amount, perhaps helping with fatigue issues from a long escort missions.
Along the same lines, radial engined fighters with exhaust exiting like the FW-190, LA-7 and to some extent later Zeros etc, must have been some of the louder fighters to fly.

[RC20]

Keep in mind the P-38 and P-47 used both Turbo and Super chargers.

The breakdown gets messed up in how they referred to the two types of pressure boost devices.

Ala Turbosupercharger for the gas turbine driven.

Now we would separate it out and call a mechanical drive boost of roots or centrifugal design (or others) as a Super Charger and the Gas driven on as a Turbo charger.

P-38 I believe was relatively quiet. Don't know about the P-47

P-47 size was driven by putting the turbo charger in the back and all the routing and plumbing involved. On a bomber that was easily handled in the nacelle but a fighter had issues fitting it (the P-38 went around it with the twin booms)

[Pumpkin]

I worked a lot with engine boosting systems, to me, those 2 planes had what appear to be turbochargers.
In fact, one cheap and dirty way of plumbing a turbo on a car is to locate the turbo back where the mufflers would normally go. Makes me wonder if someone got this idea from the P-47??
In regards to the P-47, all the turbo plumbing would have made an additional layer of protection for the pilot. Yes, the pilot would have lost power/boost if hit in these areas but his plane should have still been able to fly.
Turbos make fairly decent mufflers on gas and diesel engines, mufflers on these vehicles don't have to have the sound supressing qualities of a non-turbo car/truck.

[RC20]

The Navy used two superchargers, I think some were series and some were cut in or out depending on altitude.

The sad reality on t he Allison was the Army Air Corp did not let them develop two stage or multi speed super chargers (aka Merlin). P-38 got around that, AAC was pretty twisted mentality but then the un-escorted bomber doctrine and the refusal to accept it was horribly flawed.

The Allison had a number of advantages over the Merlin, far more durable and reliable, fewer parts as well as bigger displacement. Developed right, it could have more than equaled the Merlin and no need for the Merlin Mustang.

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By the definitions created at the time the devices were created, a super charger is powered by a direct mechanical connection to the engine. Usually a belt an pully arrangement. A turbocharger is powered by the exhaust gas of the engine. Both perform the same general function, but use separate methods for the power needed to do so.

WWII proved that pre-war US military doctrine was seriously flawed in a great many areas, all the way from the concept down to the tactical level in a lot of areas across the entire military spectrum.

To be fair, part of the reason was that in the decades (or more) between the concept being developed (and refined in peacetime) and the actual use in war a decade or two, or more of improved technology had seriously changed the playing field.

In the air, on the ground and on the sea, things changed a LOT between the wars, particularly from the mid 30s on.

"The bomber will always get through" was, at one time, possibly true, back when bombers were nearly as fast (and in some cases, slightly faster) than the fighters, and both sides were armed with single or a pair of rifle caliber machineguns. When designs changed in the mid 30s, the advantage went heavily to the fighters, and by the early 40s even the die hard stalwarts of the concept had to admit failure. Escorts were needed.

Another thing that kept out moded doctrine in place (besides inertia) was the active resistance of individuals in positions of authority to change they didn't feel necessary, and particularly if the change involved added expense. And then there is also the fact that a needed change was proof that what they had been doing wasn't good enough, which implied that they had been wrong, and resistance to admitting that caused almost no end of trouble.

The P-39 and P-40's intended mission was not high altitude combat. Their "job" was to be defending the invasion beaches and the air space above them. Fleets of high altitude strategic bombers striking deep into the country was not a possibility when those aircraft were designed, and so not only did they not have a need for a supercharger there was no money to make them, before the war. High altitude interceptor and long range escort was going to be the role of the P-38, which was still under development when the war began on 7 Dec 1941.

The job of the machine gun was to support the infantry squad, with suppressive fire. Individual soldiers were taught to fire only when they had identifiable targets. When we went into actual ground combat (on Guadalcanal to begin with) this concept proved "sub-optimal", and was changed in fairly rapid order by returning veterans.

Tanks were not suppose to fight other tanks, this was the job of tank destroyers. Our TDs were essentially tank like self propelled AT guns without a tank's armor. This led to problems and a lot of losses when actual combat proved that you couldn't easily keep separate the functions.

A penny pinching Congress kept the military budget small, until virtually the last minute, and that resulted in many problems simply because the military did not, or could not do enough pre war testing of many weapons systems.

Our torpedoes are, today, a classic example, though at the time, the multiple flaws were kept secret from the people, and also were not addressed in a timely manner.

The list is long, and covers all fields in various degrees, and its quite easy in hindsight to see many things that ought to have been done better, but give credit where it is due for the things that they did recognize and change during the war.

[Pumpkin]

“Another thing that kept out moded doctrine in place (besides inertia) was the active resistance of individuals in positions of authority to change they didn't feel necessary, and particularly if the change involved added expense. And then there is also the fact that a needed change was proof that what they had been doing wasn't good enough, which implied that they had been wrong, and resistance to admitting that caused almost no end of trouble.”

Just think how different things would have been had the Brits in charge not told Frank Whittle to go have a few pints.

[davidsog]

A turbocharger is powered by the exhaust gas of the engine. Both perform the same general function, but use separate methods for the power needed to do so.

Correct. The key difference being generation of power.

Superchargers are near instant power giving a pilot in a dogfight full use of the power band.

Turbochargers, especially in the early days, create more boost pressure but at the cost of lagging just like a jet engine.

That means you do not have instant power on demand.

The P47 was supercharged and turbocharged, however they did not operate independently. Instead, the normal use was to keep the throttle full forward and use the supercharger/turbocharger to change power.

Those power changes were not instant. You are not going to stall the airplane for example and then power out of it. It just doesn't respond that quickly.

If you try to use the throttle instead of the boost you will collapse the system and induce a compressor stall in your turbine.

[davidsog]

Just think how different things would have been had the Brits in charge not told Frank Whittle to go have a few pints.

Exactly. It's a shame what they did to Sir Frank. The RAE failed to capitalize on it but the RLM did not. Germany flew a jet powered prototype using Sir Franks Patent.

So, there we have it. The man who invented the jet engine is not even credited in his own homeland. Oh well. At least he's got his ring road in Derby.

https://www.dailymail.co.uk/news/art...d-country.html

[Pumpkin]

Anyone wonder why the USAAF didn’t just use a fixed wing F4U?
Should have been lighter, possibly could have added two extra guns.
Edit:
Instead of the P-47 (absolutely NO disrespect intended to the Jug).

[davidsog]

Anyone wonder why the USAAF didn’t just use a fixed wing F4U?
Should have been lighter, possibly could have added two extra guns.
Edit:
Instead of the P-47 (absolutely NO disrespect intended to the Jug).

Because no other airplane was as maneuverable and nimble at high altitude as the P-47. Not even a Spitfire.....

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Even if the Thunderbolt's performance had been inferior (and it certainly was not!) the Army wasn't going to adopt a NAVY single seat fighter.

[RC20]

nyone wonder why the USAAF didn’t just use a fixed wing F4U?
Should have been lighter, possibly could have added two extra guns.
Edit:
Instead of the P-47 (absolutely NO disrespect intended to the Jug).

Because no other airplane was as maneuverable and nimble at high altitude as the P-47. Not even a Spitfire.....

Two come to mind right away. The AAC realized fights were occurring up where the Bombers were (25,000 feet). Corsair was not optimized for those heights.

I would rank the Corsair and the Jug as equals. Towards the end of the Pacific campaign, it was more and more Corsair vs Hellcat. It was more versatile and air support became as big an aspect as anti air.

What the AAC did not need was the Mustang. Jug could do the escort, they deprived it of drop tanks. That was the AAC failure to adjust. Once doctrine does not work, adjust.

Post WWII and the Thunderbolt disappeared (and the N model was really spectacular). AAC did not want to ground support and they kept the pretty Mustang (its a beautiful aircraft but at the cost of a lot of lives).

The T Bolt was not nimble. It was better than most think but it was not Spitfire nimble, watch the one on one dogfights on the U Tube (Growling Sidewinder is good).

note on TD: That is a bit of a myth though it had some basis. In US doctrine, tanks were breakthrough, ergo the 75 mm gun adequate for German armor but a good HE load. But they did understand Germans would respond with tanks (and latter non turret TD) and they would take them on, it was not the main goal.

TD doctrine was flawed as it was rush them to a endangered point. Try to rush anything anywhere when a battle started, yeah, over hill, over dale we will hit the fast road trail that is full of troops, ammo, artillery all moving to the front.

So they just issued each division a battalion of TD and a Battalion of Sherman's.

Ok, back to Corsair. What was the most effective ground attack in Kore? Yep, Corsair and particularly Marine units that focused on ground support. It was the key factor that got them out of the Chosin Basin. Yes a lot of factors, discipline, teamwork, leadership but Corsair gets huge credits.

No, Super Chargers in aircraft are not belt driven (cars yes). they were all gear driven.

[RC20]

The P-38 was in development before WWII.

And you can't lay the issue of Superchargers on doctrine. A lot of the German assault on UK was at 20,000 sometimes 25,000 feet. Clearly combat that high was a thing and the AAC did not adjust at all.

In fact, Republic had drop tanks all ready to go and built into the Jug, AAC refused to let them build them.

The AAC literally killed bomber crews trying to prove a flawed doctrine. Yea you got to start someplace, but if you don't adjust, its ego and arrogance.

Massive failures in AAC leadership to this day in the form of the USAF. Its the pretty toys.

That is why we fly ancient tankers (slowly being replaced but not one for one and a KC-46A does not haul that much more fuel let alone you need tankers in a lot of places not fewer bigger ones)

[RC20]

The P47 was supercharged and turbocharged, however they did not operate independently. Instead, the normal use was to keep the throttle full forward and use the supercharger/turbocharger to change power.

That I did not know, thank you.

The C-130 uses the same approach, prop pitch mostly vs throttles.

Turbo lag not an issue with a Bomber, one way to avoid it is keep it spooled up and use a waste gate.

Now we have variable vane stuff.

[RC20]

The P-39 and P-40's intended mission was not high altitude combat. Their "job" was to be defending the invasion beaches and the air space above them.

True, it was our beaches not someone else's of course.

But you did have a Super charger, you could not fit a Turbo (P-47 designed around it and the P-38 of course did the same differently).

The Navy was using two in series or replace (depending on which fighter) so it was well known. Navy also dropped the Allison and went with the better Radial.

The AAC was enamored with the V-12 Liquids for fighters. Spitfires had either dual stage or dual speed.

Its not that the AAC did not have the info to adjust, they just would not. They were desperate when they took the Merlin Mustang (it of course was what a real fighter should have, V-12 Liquid)

Little know fact was the Allison had the better cooling system and could run on far less glycol.

Allison repeatedly asked the AAC to allocate money to Super Charger work, they refused, then took the multi stage Merlin.

An Allison Mustang would have had better odds, still an issue with cooling loss but better by quite a bit. It makes you want to cry, the potential was there with a better engine than the Merlin was.

And most do not know, P-40 was built into 1944, ground attack and it could hold its own against a FW-190 or ME-109. Not beat them but could self defend.

The FW-190 was a low to medium altitude fight er to start with and a lot of its build was just that.

[Pumpkin]

RC20,
Great factual point about the P-47 excelling at the altitude the bombers flew at.
I had actually given that some thought.
Another thought on the P-47s legendary ruggedness, how many projectiles did its boosting system keep from injuring/killing the pilot? Obviously mostly from behind but surely it accounted for some deflection. Sure, power would suffer but the plane should have been able to limp back to safer lands.

[davidsog]

Great factual point about the P-47 excelling at the altitude the bombers flew at.

You had to get somewhat higher for the P47 to come into its own. It would excelled at altitudes the next generation of bombers flew at not the contemporary B-17's and B-24's.

The B-29's and the P47 would have been a match made in heaven.

At 30,000 feet at 240kts KEAS, the P47 can still sustain 2.5G's of load factor at a rate of ~13 degrees a second.

The Spitfire MK IX can only fly level at that speed and is unable to turn at all.

[RC20]

You are welcome. Some of this is just strange.

Why the P-47 continued but the Allison engine was cut off at the knees?

A guy called Greg does some great U Tubes on the Aviation end, mostly he is a power guy involved in cars but he has taken that and referenced back to WWII particularly and the various engine power schemes and affects.

It turns out a P-47 was the first long distance fighter over Berlin (by a day, I think a P-38 was next).

The AAC by not allowing drop tanks made sure the P-47 could not do mid and long range escorting. Interesting the highest scoring guy in Europe flew P-47s.

All trying to prove what the Brits had concluded previously , daylight bombing un-escorted was a disaster.

Nothing wrong with a TD thought concept, but a little known aspect was most of it was towed guns (post Normandy it was, uhhhh, Battle of the Bulge they took terrible casualties tring to man those towed TD guns). You have to read info carefully, it was not all Crawler TD by any means till the post Normandy era.

Oddly the P-47 was the perfect setup ops wise for daylight escorts and in turn, maybe the biggest accomplish was to force the Germans to send up fighters and clean them out of the sky going form Air Superiority to Supremacy by Normandy.

Ironic the P-38 was still having teething issues and it took time to clear out in which point P-47 and P-51 did the job and easier to learn to fly a single than a twin.

So a very experienced (Bong etc) group takes the P-38 and at low and medium altitude carved a trail there. Perfect for long range flights.

The P-40 could take on a Zero or Oscar, you just had to fight it correctly per Chenaults tactics.

Today Top Gun and the USN Weapons school do that training so when you meet different types you know what tactics are the right ones.

[jmr40]

Great thread that I've been following. Most of this stuff I know next to nothing about, and it's been very informative. Thanks to everyone who has contributed.

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Several of the points ascribed to the AAC were not AAC wide decisions. They were decisions made by the people running the 8th AAF operating out of England. They were not theater wide, or world wide AAC standards.

The 8th air force while a mix of everything as it formed, became the primary strategic air force under Doolittle (6 Jan 44) and his plan was to simplify things by using only one fighter and one bomber. P-47s and P-38s were sent to other commands, and those units were reequipped with P-51s. B-24s were also sent to other commands, the focus was on using the B-17, though this never got completely done during the war.

The 9th Air Force, who's main mission was ground attack, got most of the fighters the 8th AF phased out.

[RC20]

The strategic decisions all were under control of Arnold.

The failure to allow P-47 drop tanks was one of those.

The 5th Air Force on the other hand went in full hog on Aussie built ones. We can't get them from from the US, we can get them here.

Kenny was probably the best commander of an Air Forces in WWII. He was smart, he understood capabilities and happily took P-47 and P-38.

I am not saying he was perfect. But he had his eye on the right ball and that was to enable the Army to win in the South West Pacific just as it was the 8th Air Forces job to have the European invasion succeed and too often failed in that goal.

The RAF also failed to accept its role after the Battle of Britain was the same. One major failure at El Alamein was not air spotting for the artillery. That was sorted out after that battle after years of failure in the dessert.