A-36 Apache (1 Viewer)

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190A-6? How comes? I can understand the other but preferring the A-6 to an A-8 seems a little strange to me. ;)
 
cheddar cheese said:
190A-6? How comes? I can understand the other but preferring the A-6 to an A-8 seems a little strange to me. ;)

The A-6 was the best fighter variant of the A series. It was lighter and more manuverable than the A-7 and A-8 which had much more armor and tended to be setup with 4 wing cannon rather than 2. As a dogfighter, the A-6 was the better plane.

=S=

Lunatic
 
cheddar cheese said:
Ah right. Always a fan of the A-8 myself 8)

The A-8 was more of a bomber killer. Matter of personal preference.

However, I think it's pretty clear that an A6 would beat an A8 in a dogfight far more often than not.
 
The A-8 had a slightly more powerful engine and quite a bit more armor than the A-6. The only difference in the gun package was the A-6 had 2 x 7.9 mm machine guns in the cowl where on the A-8 these were replaced by two 13 mm guns (which were very weak for their caliber) - not much of an improvement.

Some later models of the A-8 had the two outer 20 mm guns replaced with 30 mm MK108's, but these were even heavier than the 20 mm guns and nearly useless for dogfighting.

On the dogfighter configuration the outer pair of guns were usually not fitted.

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Lunatic
 
DerAdlerIstGelandet said:
As was said before the A-8 was more of a bomber killer. The 30mm MK108s were used for bomber killing not dog fighting so yes they are useless.

Don't tell the Kurfurst(109) pilots that. :)

The A-8 could have a much more powerful engine than the A-6, if the engine used in the A-9 was fitted, and it was fitted. Many A-8s had the aux 115 l tank removed.

Depends on which /R kit is fitted but the standard A-8 had the same armour fitted as the A-6.
 
KraziKanuK said:
DerAdlerIstGelandet said:
As was said before the A-8 was more of a bomber killer. The 30mm MK108s were used for bomber killing not dog fighting so yes they are useless.

Don't tell the Kurfurst(109) pilots that. :)

The A-8 could have a much more powerful engine than the A-6, if the engine used in the A-9 was fitted, and it was fitted. Many A-8s had the aux 115 l tank removed.

Depends on which /R kit is fitted but the standard A-8 had the same armour fitted as the A-6.

The base weight of the A-8 is several hundred pounds heavier than that of the A-6, the only armament difference being the MG131's vs. the MG17's. Most of the difference is armor builit into the cowl, in front of the oil cooler ring, and around the cockpit, and the thicker armor-glass windscreen. The engine was a little more powerful in practical usage, not a lot - it was after all just an twin-wasp derivative that had been pushed about as far as it could be pushed already.

=S=

Lunatic
 
All 190A a/c had 50mm thick windscreen glass. The standard A-8 did not have any armour around the cockpit. It was the /R8 that had it added.

The standard A-8 with the D2 engine had 6.5mm oil cooler armour. On the A-8/R8 and the A-8 with the TU engine, this was increased to 10mm.

The standard A-8 with the D2 engine had 5.5mm oil tank armour. On the A-8/R8 and the A-8 with the TU engine, this was increased to 6.0mm.

The D-2 and TU a/c had 12mm head armour which was increased to 20mm on the /R8.

The 801TU put out over 2000hp. Some say 2300hp.

The 115 l aux tank, which was often removed, added 200lb to the A-8.
 
KraziKanuK said:
DerAdlerIstGelandet said:
As was said before the A-8 was more of a bomber killer. The 30mm MK108s were used for bomber killing not dog fighting so yes they are useless.

Don't tell the Kurfurst(109) pilots that. :)

The A-8 could have a much more powerful engine than the A-6, if the engine used in the A-9 was fitted, and it was fitted. Many A-8s had the aux 115 l tank removed.

Depends on which /R kit is fitted but the standard A-8 had the same armour fitted as the A-6.

Oh dont take me wrong. Any Fw-190 was a very formidible fighter aircraft and even the allied pilots would agree that seeing the butcher bird in the skies was not something to shrug off. I just think the A-8 was better suited for knocking out bombers then dog fighting.
 
The "Mustang" name actually came from the British, I believe. They wanted the Allison Mustangs for "rhubarbs". Fitting a Merlin into it wasn't so easy. It didn't fall in - there's a book available from the RR Heritage Trust about the subject. They had to enlarge the air scoop and radiator duct, and there was all sorts of plumbing that needed to be routed. The smaller air scoop was most likely the reason why the Allison Mustang was faster on the deck.

(There's something weird going on.. why are posts from the FW-190 topic in the A-36 topic??)
 
Iskandar Taib said:
The "Mustang" name actually came from the British, I believe. They wanted the Allison Mustangs for "rhubarbs". Fitting a Merlin into it wasn't so easy. It didn't fall in - there's a book available from the RR Heritage Trust about the subject. They had to enlarge the air scoop and radiator duct, and there was all sorts of plumbing that needed to be routed. The smaller air scoop was most likely the reason why the Allison Mustang was faster on the deck.

No, the Allison's single stage supercharger and its prop were better suited to low altitudes. The scoop size didn't matter, as its drag was canceled out by the radiator thust.

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Lunatic
 
The early P-51/A-36 radiators were not as efficient as the the later Merlin engined P-51s were.There was a complete re-design of the intake.
 
KraziKanuK said:
The early P-51/A-36 radiators were not as efficient as the the later Merlin engined P-51s were.There was a complete re-design of the intake.

The gutter gap was found to be insufficient at high speeds, espeically at higher altitudes where boundary layer seperation occures more easily.

I was not saying the P-51A radiator was as efficient as the Merlin powered models, it didn't have to be. But the point is it was not faster because of the smaller scoop, since in both cases the drag from the scoop is canceled out by the thrust from the radiator.

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Lunatic
 
That is pretty much what I have read.

The radiator scoop for the later model P-51's was well designed. While the scoop caused some profile drag, the heated air exiting the exhaust expanded and created enough thrust to compensate for the drag anytime the air was heated above 170° F. The stock P-51 radiator is large, being 14' deep and 21" wide by 28" high, and it was sized to cool the engine at 3800 RPM and 55 lbs. of manifold air pressure (MAP). Racers go to 4,000 RPM and 120+lbs. of MAP, so additional cooling is required. Rather than add an even larger radiator, racers added cooling water spray bars in front of the radiator to accomplish the same thing. Spraying cooling water onto the P-51 radiator is necessary but reduces the thrust created in the exhaust because it also cools the air, decreasing hot air expansion.
http://www.aafo.com/racing/news/98/intrepid.htm
 
From what I understand, you never get as much thrust out of the Meredith Effect as it takes to overcome the drag of the radiator inlet. You can recover quite a bit, but it is never zero sum or better. In any case, there is only so much thrust that can be generated out of the heat produced by the engine. Make the inlet larger than is optimal, and you get more drag. The inlet size really does matter - the bigger it is, the bigger the drag. You make it just as big as it needs to be to cool the engine, no bigger. If the size didn't matter, then you could make the inlet as big as you wanted. This also applies to radials, by the way.

See:

http://www.supercoolprops.com/ARTICLES/gwhite.htm
http://www.supercoolprops.com/ARTICLES/ducted_cooling.htm

I don't think the Allison was making more power than the two stage Merlin, even on the deck. If they did, people would be dumping the two stage supercharger for racing! Instead, they finesse the inlet, and spray liquid on the radiator core. Incidentally, Supercool is wrong about the Spit IX. It did use the Meredith effect (see Quill's book), though the radiator design wasn't as efficient as on the Mustang, and there were other sources of drag. The Mustang manages to hide most of the bulk of the radiator core inside the fuselage - it takes up a large amount of space below and behind the pilot, while the scoop and inlet represent a comparatively small "bump" in the fuselage profile.
 
Iskandar Taib said:
I don't think the Allison was making more power than the two stage Merlin, even on the deck. If they did, people would be dumping the two stage supercharger for racing!

True, but the warplane version wasnt running in high blower on the deck either! Youve gotta compare apples to apples here. The configuration that a P-51D would run on the deck in 1945 is way way different than a racing Mustang at Reno today.

In 1945 configured the way they came from the factory an Allison engined P-51 compared VERY favorably with a Merlin engined P-51 up to about 10000'. Somewhere above that the Merlin shifted into high blower. Ive said it before and Ill say it again.. it wasn't the Merlin in its self that was so great it WAS the fact that the Merlin could get enough air at higher altitudes that made it a performer. Try to run it on the deck in 1945 in high blower and youd surely get a lot more power... but not for long!!
 

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