Hardest plane to take down in WW2?

[kool kitty89]

What I was saying about the F2A, was that it may have developed into a powerful and reliable a/c if it hadn't been for the internal problems with Brewster, as their designers seemed to have some good ideas, it was just hard to implement them in such an atmosphere, case in point with the Brewster Corsairs. And certainly putting a max weight of anything more than 7,000 lbs in the F2A was downright worthless, with ~6,000 lbs probably being the maximum useful gross combat weight (ie not for long range patrols), it probably would have been better to limit the internal fuel tank size on the F2A-3 to 1/2-2/3 of what was done, and focused on improoving self-sealing and structural problems, or just limiting weight, as the F2A-3's frame and gear were considderably stronger than earlier models, but the large weight increase made this still insuficient.

And with the F6F comparison, I meant that perhaps a larger, more powerful a/c based on the F2A's general design may have developed in better conditions...

[kool kitty89]

The P-43's visibility was improved (along with the primary problem of ground looping) with the addition of a larger tail-wheel, though the other problems and disadvantages over the F4F would still hold up... Though I'm noth sure about the stall speed, the stall characteristics of an eliptical wing are not verry freindly o carrier opperations, though the Seafire had them, but with low wing loading and good flaps...

I still wonder why the tanks of the P-43 weren't improved though, it shouldn't have been too dificult, and the AVG, as well as USAAF operators with nothing only P-40s and P-39s, would have really apreciated a craft with such high altitude performance. (though the Merlin P-40's had decent performance at altitude it still dropped off above 20,000 ft, and these weren't available until later anyway, by which time many of these US units were receiving P-38s or P-47s)

[renrich]

I think that part of the problem with a lot of the AC that were designed in the early 30s was that there was beginning to be a huge leap forward in technology with increases in performance brought on by more powerful engines and better aerodynamics. Couple all the performance advances with the new manufacturing processes necesary to support this new performance and there were a lot of things which could go wrong and reliability was compromised. AC design was approaching a new frontier. Just think, in the early 30s we could not design a fighter that would go 300 mph. By the mid 40s we were reaching the pinnacle of prop driven performance.

[HoHun]

Hi Koolkitty,

>Though I'm noth sure about the stall speed, the stall characteristics of an eliptical wing are not verry freindly o carrier opperations, though the Seafire had them, but with low wing loading and good flaps...

The US Navy probably would't have accepted the Seafire for carrier service either. Mike Crosley's "They gave me a Seafire" and "Up in Harm's Way" give excellent accounts of the Seafire's problems, the latter going into considerable detail on the aerodynamics responsible for them. (Crosley was a Seafire pilot in WW2 and an ETPS-trained test pilot after the war, so he's well qualified for an analysis.)

Regards,

Henning (HoHun)

[kool kitty89]

Plus the P-47 had time for redesign durring development in addition to the high priority. The P-43 may have been more difficult to modify effectively with its steel tanks. The "self sealing" tanks of the P-43A may have been steel tanks coated with soft expanding sealing material, a configuration which was prooven to be unsatisfactory in practice.

[kool kitty89]

On the Seafire, the US navy also disliked liquid cooled engined a/c due to the need to store the highly flamible Ethylene Glycol coolant on board (as well as the added reliabillity of radials, somthing very important when flying over water). Though this was less of a concern with the 70/30 water/glycol mixes later used (more efficient and cheaper too) and the Navy did considder the P-51 for long-range carrier based service, though this never panned out. (though the P-51H was found to have adequate handeling and better low-speed control and was suitable for service a long-rang fighter was no longer needed by that time)

[FLYBOYJ]

Kool Kitty - the F2A (Navy and Marine Birds) was a dog made by a poor manufacturer. Although placed in the worse possible condition for initial deployment (A critical battle where the aircraft AND tactics were poor) the aircraft still showed its liabilities in its theater of operations. Read "Bloody Shambles" and there were dozens of design flaws in the aircraft that although easily corrected in the field, would play havoc for the Brits who had to fly her. An improved version? I don't think so - the best use for the F2A was it's deployment at Pensacola as an advanced trainer!

[Elvis]

Hey kiddies, I'm back from the dead and just skimmed over the past 4 pages of dialogue on the various a/c and engines, that I missed while I was gone.

Ok, RENRICH, this is coming from a guy with 35+ years of mechanical experience.
Yes, an engine can run with a "dead" cylinder.
You may have run across this phenomena yourself, in times past.
The condition is called a "miss". As the engine runs, you hear a slight, but noticeable "hiss" coming at regular intervals from the engine. That's the resultant pressurized fuel/air mixture leaking past the rings (and probably the valves, to some degree) because the cylinder did not fire.
A cylinder's operation can be compromised by something as simple as a chunk of carbon breaking loose and holding a valve open.
The cylinder will fire, but the "charge" will escape through the opening. This is known as a "backfire". If it blows through the exhaust, its that valve that's open. If it blows back through the carburetor, its that valve that's open.
Simply put, a cylinder needs to SEAL in order to work properly.
If it cannot, it won't work, or won't work as well as it should.
Also, we're talking about engines with 12-18 cylinders. If you incapacitate one or two cylinders on an 18-cylinder engine, BFD! There's still 16 or 17 cylinders to take up the slack.
Its like having a miss with the V-8 in your car. It won't run quite as well, but it'll still run good enough to get you home or to a garage.
A carburetor cannot be "injected" (not sure if you were the one asking that, but I recall someone asking if the Allison's used an "injected carburetor").
Fuel injection and Carburation are two similar, but different fuel systems.
The closest you get to an "injected carburetor" is what is now known as "T.B.I" (any of you who own GM products may be familiar with that term), which means "Throttle Body Injection".
A carb is a really just a big air box where the fuel "mists" in under low pressure (5-7 psi). The air running through the venturi (commonly known as a "barrel") sets up a low pressure condition at the point where the fuel "mists" in. Since the fuel is pressurized to a higher point than that part of the venturi, it spreads rapidly and this enhances its ability to mix with the oncoming air.
From there, the mixture simply makes its way to the cylinder, as which point its ignited and creates power.
With a fuel injection system, fuel is brought to the engine under low pressure (5-7psi) and then pumped into either an "injection pump" or the injector itself, depending on the particular type fuel injection system being used.
An injection pump is simply a pump (if you will) that increases the pressure of the fuel to whatever it needs to be at, in order to work in the engine.
On most gas engines, its around 25-50 psi. On a diesel powerplant, it can be as high as 2000 psi, because of where and when the fuel is introduced into the cylinder.
With the injection pump type system, the injector becomes (really) just a gloified poppet valve, with the spring pressure set to release the fuel from the injection pump, at its rated pressure.
I think the system used on the DB601 used an injection pump (inline), because I seem to remember seeing one, although I cannot be certain, as of this writing.
BTW, the other type of injection system uses what is known as a "Unit Injector".
In this type, there is no "injection pump". Fuel comes from the tank, through a filter, through the fuel pump, through another filter and straight to the injector, all at low pressure.
The injector, has a plunger and spring inside of it that is timed off a rocker arm that is connected to the camshaft and the forcing of the fuel into the cylinder, via the plunger, is what pressurizes it.
Any 2-cycle DDA motor uses this type of fuel injection system.

...and a "Jug" is just an old term for a cylinder on ANY motor. It's ususally associated with air-cooled engines, since they all seem to built like a motorcylce engine, in which the cylinder and head are separate units that fit into the engine block.

As for Allison V-1710 vs. R-R Merlin, I recently traded a series of email with one of my boyhood heroes, who worked on the Unlimited Hydroplane circuit back in the 1970's and '80's.
I asked him why the Allison were never as competitve as the Merlin's were, as the Allison was 300 lbs. lighter and displaced an additonal 60 cubes.
He told me he wasn't sure, but he's seen enough of both to note that the Merlin's were built a little heavier and they seemed to be able to pull more power out of those engines, probably due (in part) to that.
I know there were some tests during WWII, of the Allison, and it successfully pulled 1600HP with a two-stage supercharger with no sweat, but by then, Packard had the lease on building the Rolls engine and priority was simply given to that engine, which meant it got the two-stage supercharger and the Allison was saddled with the single-stage unit.





Elvis

[kool kitty89]

Still the F2A could have turned out better with a better situation with the company...

In the cercumstances it developed in, it was certainly not a great a/c (by the time it reached the F2A-3 or Buffalo I), but it's had to tell how it would have done if it had been developed better from the start, though the basic design was obsolete by late 1941 and certainly by the time it saw service... Though so were several other planes that continued to serve later on, some with better reputations (much due to early acomplishments when they were not so outclassed), many of which did just as poorly as the Buffalo. (the P-40 would not be one, though it was outdated by almost any standards, though many P-43s met a similar fate, and the Hurricane wasn't a shining fighter in the PTO either, though decidedly better than the Buffalo as well, and far from the worst, though the range was quite short)

[Elvis]

Kool Kitty,

Too many conversations have broken out in this thread.
By "it", are you referring to the F2A?
Fine fighter, if they'd either left it alone or developed it better.


Elvis

[kool kitty89]

I asked about the carborator, and I'm not really sure why I phrased it like that. I think I just meant to ask what type of carborator the V-1710 used. Early Merlins used side-draft carborators, but later they switched to a system better able to handel negative G-loads and inverted flying, though the "Tilly Orifice" was used as an intrim measure to allow limited improvements.

The DB-600 series engines used direct fuel injection iirc, though this was a less efficient configuration it offers more power iirc. My knoledge of this is fairly limited, but from what I've raed and heard, direct fuel ingestion didn't get practically efficient untill the advent of computerized engine regulation in the 1980's. (otherwise fuel was injected durring non firing cycles as well). I do wonder why TBI wasn't used earlier, as computerization isn't necessary and it offers better power and performance under high G loads. (and shouldn't require any complex regulation to be practical, with a carborated engine being realitively simple to modify to such a system)

From what I know, the V-1710 was built with vercitility in mind with one standard version (with just the integral supercharger) to be produced with a dedicated excesories section for any added applications. This way one production line could produce engines for a variety of uses, the various excessories being added separately. In fact the AAC hadn't been originally interested in the design and it was the nave that funded the initial prototype and used the first production version V-1710A (an un-supercharged revercable version for use on the Arcon and Macon a/c carrier rigid air ships, the V-1710B). Though by this time the AAC was very interested in the design, and was giving considderable support. Though it was an earlier AAC decision that the focus was to be put on turbochargers for altitude performance, not mechanically driven superchargers (thought to give an advantage over the European counterpars focusing on mechanical superchargers). Thus the V-1710 was to be built with the integral low-altitude supergharcer, with a turbocharger added if aditional altitude performance was needed. (another flaw in the AAC's logic later on was that the US was immune to high-altitude bombers, and thus the focus should be put on low-altitude close support and strike fighters, and not high altitude interceptors, luckily the P-38 continued with turbochargers despite this). Eventually an auxillery supercharger was developed (as an afterthought) and was made available for V-1710-45 and later models iirc. Though the early versions were very simple and lacked intercoolers or aftercoolers, though water-ingection was introduced early on (allowing boosts of up to 1,800 hp in combat conditions). However these simple versions were realitively reliable and practical (compared to turbocharges, which often prooved problematic to mate to the engine, as well as bulky; often the latter worsening reliabillity as well as porr ducting among other things resulted in trying to instal a turbocharger) and effectively allowed critical altitudes of 25,000 ft to be acheived. Later versions added aftercoolers, and later, intercoolers as well, though many prooved to be unreliable or maintence heavy, particularly those used on the P-82s in place of Merlins. (G-series iirc, though I'm not sure of the validity of these particular claims)

Early merlins were less powerful than the Allison counterparts, though the power increased to around the same level with the same higher octane fuel the V-1710 had been running with. (~1150 hp with the Mirlin III iirc) though with the heavier structores of the Merlin XX along with the improved supercharger, power levels of 1,300+ hp were acheived with high-octane fuel.
From what I've seen the Merlin and V-1710 were capable of similar power levels in various models of similar time periods, albeit thhe V-1710 did it at 200-400 rpm higher. Though the Griffon largely beat these, the Turbo-compound V-1710 eventually produced nearly 3,000 hp at high efficiency (still limited by turbine stresses early on), though this wasn't produced until well after the war.

[kool kitty89]

With the F2A, it reallyis hard to say how further development would have gone, hhi the large number of small problems had been corrected and internal fuel limited to allow for ~900 mi max range, with the same other improvements of the F2A-3, and better self-sealing and landing gear. (the gear had actually been progressively improved, but the increase in weight which progressed as well, maintained the problem, somthing that would be improoved with smaller tanks)

Still the horrible situation Brewster was in due to overgrowth with lack of sufficient management killed any real chance of reasonable progress made in quality, quntity produced, or developmental improvements.

[HoHun]

Hi Koolkitty,

>The DB-600 series engines used direct fuel injection iirc, though this was a less efficient configuration it offers more power iirc.

Hm, if you mean fuel-efficient when you say "efficient", the one striking feature of the DB600 series actually is its low fuel consumption at high power settings.

The DB605A consumed about 480 L/h at 1475 HP, or 244 g/HP/h.

The V-1650-7 consumed roughly 800 L/h at 1660 HP, or 277 g/HP/h.

(Figures not entirely accurate as they probably used fuels of different density, but you get the idea.)

Regards,

Henning (HoHun)

[kool kitty89]

I'm not sure why this would be... I messed up erarlier though, the DB-600 wasn't injected, the 601 and later were.

Everything I've read or heard has said that, despite offering excelent power and throttle performance, it offered poor fuel efficience and very high emmissions (even up through the 1970s) due to unburnt fuel resulting from injection every cycle and inherantly running rich (in the exaust).

Maby the German design was somthing akin to TBI, though I though it was direct injection. (tbi offers similar efficiency to carborators without the need for eletronic regulation and still offers some, though not all, of the improved power, thottle, and G-load performance of direct-injection)

[FLYBOYJ]

Originally Posted by kool kitty89

Still the F2A could have turned out better with a better situation with the company...

I doubt it - there an old saying - "You can't polish a turd."