Nailed it, Zipper! Nice explanation.
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Nailed it, Zipper! Nice explanation.The key here to think of is not g-load but lift. Higher g-loads require more lift, more lift results in a higher AoA, all things being equal. This results in a higher velocity over the top of the wing
A6M Zero. The aircraft had a lot of shortcomings (fragile structure, no self sealing tanks, engine would quit in a nose over maneuver and more.) Once the US airmen figured out how to fight it, it was done.
Nope, except for lack of self sealing tanks.
I'd also like to add the Spitfire. Was a good airplane during the beginning of the war but was overtaken by a lot of other types and was left only with its glorious reputation and nothing more.
The NAA XB-28 with turbosupercharger was contracted in Feb 1940 for the R-2800-27. Pressurized and aerodynamically sound it was as fast as the Mustang I at 25K. It died eventually because there was no mission other than fast recon (p-38 fine), with medium range and 4K bomb load.Martin certainly had plans for two stage R-2800s. XB-27
Martin actually offered 15 different configurations for their proposal that culminated in the contract award for the B-26. The Army chose the single stage R-2800 version with short wings, because that was the configuration that promised the best performance with the engines available at the time. Other configurations had projected speeds in excess of 400 MPH, but required technology that was not yet available in 1939.
Good Lord, I actually understood that!Zipper730 said:
The key here to think of is not g-load but lift. Higher g-loads require more lift, more lift results in a higher AoA, all things being equal. This results in a higher velocity over the top of the wing
Higher AoA results in higher CL. The two conditions are not necessarily analogous to higher G loads - only in fast turns, zoom climb or dive pullout. But cruise at high altitude require high AoA with no attendant G increase, near stall on final approach aren't a high G 'thingy'. Transonic dive at 1G result in higher velocity over the wing and a shock wave - but no increase in G until pullout.
Wait, I thought the stiffer wing started on the Mark VII, and that was when the plane theoretically could take a speed of 825 mph (if the prop didn't exist, the fuselage was different, and the tail was redesigned). This was aileron reversal only?Due to the unusually high speeds at which the Supermarine Spitfire could dive, this problem of aileron reversal became apparent when it was wished to increase the lateral maneuverability (rate of roll) by increasing the aileron area. The aircraft had a wing designed originally for an aileron reversal airspeed of 580 mph, and any attempt to increase the aileron area would have resulted in the wing twisting when the larger ailerons were applied at high speed, the aircraft then rolling in the opposite direction to that intended by the pilot. The problem of increasing the rate of roll was temporarily alleviated with the introduction of "clipped" wing tips (to reduce the aerodynamic load on the tip area, allowing larger ailerons to be used) until a new, stiffer wing could be incorporated. This new wing was introduced in the Mk 21 and had a theoretical aileron reversal speed of 825 mph (1,328 km/h).[2]
W-w-w-wait... The drawings were reworked simply to mirror and flip them? I thought there was a problem with the British and US inch being like a tiny fraction of an inch off and that's why there were problems with British aircraft using American V-1650's?Bollocks.
One of the biggest myths out there.
The fact is that Packard redrew the drawings because they had to change them . . . from 1st angle projection . . . to 3rd angle projection
Higher coefficient of lift sees a greater pressure differential along the top/bottom of the wings, and a higher velocity over the top?Higher AoA results in higher CL.
That adds up.Transonic dive at 1G result in higher velocity over the wing and a shock wave - but no increase in G until pullout.
Honestly, I thought that they carried a small center-tank at first, then a pair of wing-tanks, then a pair of wing-tanks, and a paper-tank in the middle.P-47 Drop Tanks in ETO:
- July/Aug 1943: used 200 gal ferry tanks (particularly filled). Not a drop tank but could be released in flight, but more often than not, it failed to jettison.
- 31 Aug 1943: 75 gallon tear drop shape, initially designed for P-39. In 1944, used as underwing tank.
- Sept 1943: 108 gal British designed/ manufactured paper tank. Used as wing tanks Apr 1944
- Feb 1944: 150 gal drop tank. Used as under wing tank 22 May 1944
- Feb 1945: 215 gal belly tank
So, they had a kluge available that effectively pressurized them?These P-47 groups had devised a way to pressurize their tanks using air pressure from the airpump that typically bled off into the exhaust, a certain type of thermostat that was scrounged locally and a glass elbow tube all before August '43.
I never knew that about the F4U-1Battle over Germany, January, 1944
P-51B, P-47PreD-25, F4U-1, P-38J, Escort Ability vs. Me-109G and Fw-190A-8
. . . .
I wanted to try to come grasp how these four aircraft would perform in the escort role over Germany against their German opponent. The F4U was thrown in because it was brought up as an aircraft that should have been built instead of the P-47 (and I think the P-51, too).
That all adds upFirst I wanted to define the requirements of an escort fighter for supporting daylight bombing of Berlin by B-17s and B-24s. This is what I determined was needed.
1. Range to fly to Berlin and back
2. Endurance to allow a meaningful combat time under enemy attack.
3. Equal-to or better capability of engaging enemy aircraft in combat at or above 20,000 ft.
I'd say that might be on the bottom end of the effective altitude: It'd cover the B-24's without much difficulty, but the B-17's typically flew around 22500'-28000' and, it was generally best for escorts to fly 2000'-3000' to 5000' above that.The methodology I used to compare these planes were, 1) determine total internal and external fuel available each aircraft, 2) calculate fuel required to transit to target (approx. 600 miles) at 25,000 ft
I assume fuel burn would be somewhat lower on the way out. You have less airplane to move through the sky, and that's gotta do something. That said, I don't know how to calculate for that either, so...3) calculate fuel required to return to base (I used ingress fuel since I am lazy and probably didn't have this data. Still should be okay for comparisons)
That works out.4) calculate fuel available for combat, 5) calculate combat time at Normal Rated Power (NRP), 6) compare performance at 20,000, 25,000, and 30,000 ft. Since the data available was not all compatible between aircraft (it never is), some alchemy was required to generate fuel consumption at 25,000 ft. It all seems to pass the smell test.
S-weaving wouldn't be too hard to calculate: Just divide the fighter's tactical speed by the bomber's speed.Flight profile goes directly to Germany, optimum cruise, engage defenders, fly directly home. Weaving over slower bombers is not calculated but obviously would reduce time in combat.
The F4U-1's climb rate isn't that good at 20000', from what I was reading, 1940-2300 fpm seemed to be the maximum you'd get at that altitude. The speeds seem close enough.Performance at 20k ft. (B-24 Altitude)
From my understanding, however little that might be: The P-38J did have a redesigned intercooler over the earlier designs, right? I also didn't know that the powered ailerons and dive-recovery flaps weren't routinely in operation until after D-Day. From what I remember, the P-38J-20/25 were in possession of both by March of 1944...The high altitude mechanical issues were not 'solved' until the Intercooler/turbo re-design, electrical cockpit heating provided by adding a generator.
So this is when policy went from defense to offense?Not in so many words, but yes. Go Deep, incite reaction - kill 'em in the air and pursue all the way to the deck.
What Doolittle reacted to was one of his commanders stating that the role of the fighter was to 'protect' whereas Doolittle believed the role of fighter aviation was to destroy - and he had just received intelligence reports that LW was building strength in alarming numbers (January, 1944) and posed a serious threat to OVERLORD.
It is a wiki article, there were quite a few mods to strengthen the Spitfires wing, but as far as aileron reversal is concerned the speed is theoretical, problems occur long before that speed is reached.Wait, I thought the stiffer wing started on the Mark VII, and that was when the plane theoretically could take a speed of 825 mph (if the prop didn't exist, the fuselage was different, and the tail was redesigned). This was aileron reversal only?
.
That I'm aware of, as I said: I was under the impression that the wings could maintain adequate airflow over them up to 800, as absurd as that sounded. That said, I know the fuselage and tail couldn't withstand it.It is a wiki article, there were quite a few mods to strengthen the Spitfires wing, but as far as aileron reversal is concerned the speed is theoretical, problems occur long before that speed is reached.
It isn't a question of airflow but forces and rigidity. If you have an aileron reversal speed of 850 MPH then you don't have any problems at 500.That I'm aware of, as I said: I was under the impression that the wings could maintain adequate airflow over them up to 800, as absurd as that sounded. That said, I know the fuselage and tail couldn't withstand it.
If you're doing 800, you've got a lot more to worry about than aileron reversal. How about shock waves, center of pressure shift, and mach tuck for starters? Maybe some control surface flutter as well?I was under the impression that the wings could maintain adequate airflow over them up to 800
I think that if you are doing 800MPH in a Spitfire you have lost most control surfaces a while ago.If you're doing 800, you've got a lot more to worry about than aileron reversal. How about shock waves, center of pressure shift, and mach tuck for starters? Maybe some control surface flutter as well?
Roger that! ("Roger" in the R/T sense, not the piratical or Shakespearean)I think that if you are doing 800MPH in a Spitfire you have lost most control surfaces a while ago.
Packard was a fairly major player in the aero-engine business for a few years after WW1, but was out of the aircraft engine business by 1940. I suspect that its management felt that the market for aircraft engines didn't promise sufficient ROI.
The US engine designation system is based on two very broad parameters: displacement and general configuration. It's not designed to cause confusion, but the Navy and Army's aviation services were not really concerned with the engines' internal details. Engines with the same configuration, displacement, and technology level will be similar in weight, installed volume, and performance, the parameters that matter to customers.
The Merlin was two generations after the Packard V-1650; the displacement was a coincidence.
Agreed, the glass jaw of fighter planes. Can duck and punch better than most, but hit it once and it's done.Zero
It's the same with much of Germany's obsession with Wunderwaffe. Why build Bismarck and Tirpitz to face an enemy with a clear superiority in battleships when those 82,000 tons and 4,000 men could have gone towards 3,200 Panzer IV tanks or 800 U-Boats to attack from Germany's position of advantage?To me the most overrated plane. far and away, is the Me 262.
Sure it was the first jet into regular squadron operations, but the effect it had was nothing comarped with the resources expended to develop and deploy it.
The B-17 bomber stream was the SAME whether or not the Me 262 was there, and Me 109s produced in lieu of the 262s would have done more damage to the bombers, if only because so many more Me 109s could have been built using the resources dedicated to Me 262 development and deployment.
Why build Bismarck and Tirpitz to face an enemy with a clear superiority in battleships when those 82,000 tons and 4,000 men could have gone towards 3,200 Panzer IV tanks or 800 U-Boats to attack from Germany's position of advantage?
The Bismarck putting to sea was a headache for the RN, the Tirpitz not putting to sea was an even bigger one.In part to tie up an equal amount (at worst) of British ships and men and several times the Germans investment at best.
No Bismarck and Tirpitz?
British don't build 1-2 KGVs, don't plan the Lion class and/or don't build the Vanguard, instead they build 70-100,000 tons of escorts (Hunts/Black Swans, etc) and since the British could out build the Germans and Subs are harder to build than surface ships this doesn't look good for the U-boat strategy.
Similar arguments could be made about the tank production. Tirpitz especially sucked up an inordinate amount of effort from the allies (mostly Britain) with not only the long history of attacks but even such simple stuff as a battleship escort for many Russia bound convoys sucking up thousands of tons of fuel oil per trip.
see: Fleet in being - Wikipedia
for the general concept.
That theoretical speed was like 800 TAS right?It isn't a question of airflow but forces and rigidity. If you have an aileron reversal speed of 850 MPH then you don't have any problems at 500.
Mach tuck effects were the thing that had me puzzled too. I figured "good to 800" meant airflow would be good enough to avoid excessive flow separation (some degree is invariable).If you're doing 800, you've got a lot more to worry about than aileron reversal. How about shock waves, center of pressure shift, and mach tuck for starters?
Yeah, you'd need an entire reworking of the internal structure.I think that if you are doing 800MPH in a Spitfire you have lost most control surfaces a while ago.
That theoretical speed was like 800 TAS right?