Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: SunTracker on April 10, 2004, 05:28:16 AM
-
(http://www.wpafb.af.mil/museum/research/fighter/xf82-2.jpg)
PERFORMANCE
Maximum speed: 482 mph
Cruising speed: 280 mph
Range: 2,200 miles
Service Ceiling: 39,900 ft
(http://www.aeroflight.co.uk/profile/do_335-4.gif)
Performance: Max speed 474 mph (763 km/h) at 21, 325 ft (6,500 m); Max cruising speed 426 mph (685 km/h) at 23,360 ft (7,100 m); Economical cruising speed 281 mph (552 km/h) at 19,685 ft (6000 m); Range on internal fuel at max continuous power 867 miles (1400 km), at economical cruise power 1,280 miles (2050 km); Time to 3,280 ft (1000 m) 55 sec, to 26,245 ft (8000 m) 14.5 min; Service ceiling 37,400 ft (11,400 m).
How would these aircraft have matched up if they had met in combat?
-
Would imagine the DO 335 would be the better aircraft.
While a bit slower - it most likely weighs less thus making it more manuverable thus making it a better dogfighter.
P-82 "Twin Mustang" was a long range fighter/bomber interceptor more along the line of the ME-110.
Interesting thought though.
!
-
Hi Sun Tracker,
>How would these aircraft have matched up if they had met in combat?
Interesting question :-)
I'd say it mostly depended on altitude. The Do 335's DB603A gave good power at low and medium altitude, but was a mediocre performer up high. The P-82B's V-1650-22/23 on the other hand probably had the Merlin-typical good high-altitude performance (I don't have a power graph for that specific engine type).
With regard to combat characteristics, the Do 335 with its centreline layout and its hydraulically boosted ailerons certainly had an advantage in roll rate. The P-82 on the other hand offered better rearward visibility and had the advantage of having an additional pair of eyes on board.
(By the time the first P-82B left the production line, Dornier would have switched production to the Do 335B with the more powerful DB603E-1 or DB603LA engine, and especially with the latter, the performance advantage probably would have resided with the Do 335.)
Regards,
Henning (HoHun)
-
How difficult was it to aim the 82's guns?
-
Originally posted by Jester
Would imagine the DO 335 would be the better aircraft.
While a bit slower - it most likely weighs less thus making it more manuverable thus making it a better dogfighter.
P-82 "Twin Mustang" was a long range fighter/bomber interceptor more along the line of the ME-110.
Interesting thought though.
!
Actually, the Do 335 weighs nearly a ton more than the P-82, even if the Twin Mustang has full internal tanks (it would not need external tanks to operate anywhere over Germany). However, by the time they reached Germany, about 30% of the fuel would have been burned. Either way, the P-82 has a lower wing loading, becoming substantially more lopsided as fuel burns off. P-82 pilots who converted from the P-51D described the P-82 as being considerably more agile than the P-51. North American Aviation test pilot George Welch (who flew the P-38 against the Japanese) found the Twin Mustang to be, and quote, "considerably superior to the P-51D in every aspect of air combat."
What we have here is an interceptor designed to kill high altitude bombers vs. a high altitude fighter designed to kill interceptors.
I lean towards the Do 335 being far less effective than the Me 262, and far more vunerable to boot.
My regards,
Widewing
-
Hi Widewing,
>Actually, the Do 335 weighs nearly a ton more than the P-82, even if the Twin Mustang has full internal tanks (it would not need external tanks to operate anywhere over Germany).
Do 335A: 10200 kg (1150 kg fuel)
P-82G: 9080 kg (1630 kg fuel) => 7930 kg (1150 kg fuel)
>Either way, the P-82 has a lower wing loading
Do 335A: 265 kg/m^2, 0.36 kg/HP
P-82G (1150 kg fuel): 204 kg/m^2, 0.49 kg/HP
(Power loading based on maximum power.)
>North American Aviation test pilot George Welch (who flew the P-38 against the Japanese) found the Twin Mustang to be, and quote, "considerably superior to the P-51D in every aspect of air combat."
Well, there should be a difference between the 1945 Merlin-powered P-82B and the late-1946 Allison-powered versions like the F-82G I listed above.
>What we have here is an interceptor designed to kill high altitude bombers vs. a high altitude fighter designed to kill interceptors.
The Do 335 actually didn't follow any special fighter concept but was rather a high-speed bomber adapted for the fighter role (similar to the Mosquito).
With regard to the P-82B comparison, I'd say that the Do 335B held the speed, firepower and roll rate advantages, while the P-82B held the turn rate, visibility and range advantages.
(The climb rate comparison depends on the exact DB603 variant used and of course on the power of the V-1650-22/23, so I can't comment on that yet.)
>I lean towards the Do 335 being far less effective than the Me 262, and far more vunerable to boot.
Well, I'm afraid I don't know what you mean by "far more vulnerable".
With regard to the Me 262 comparison, the Do 335's main strengths was the long endurance and rough field capability (due to propeller power) so that they wouldn't have had to scramble from and land back on bases that were under constant attack.
Performance-wise, the Me 262 of course was superior to the Do 335, just as it was to any other piston fighter of the era.
Regards,
Henning (HoHun)
-
The armament comparison is interesting. Most of the Do 335s had one MK 103 engine cannon and a pair of synchronised MG 151 (there is some confusion about whether the 15mm version was used in some installations), although the B-2 added another pair of MK 103's in the wings.
The MK 103 was a very powerful, long-range gun and the MG 151/15 was also superior to the .50 in power, but their combined rates of fire were much lower than the US armament. It would probably have come down to luck; the US plane would have scored more hits but the Do only had to connect once with that 30mm cannon.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and Discussion forum (http://forums.delphiforums.com/autogun/messages/)
-
I still think the P-47M would have eaten the DO-335 alive
-
The sources I have give the V-1650-21/23/25 as being "similar to V-1650-11.
At 4,000, low blower, water injection on... 2,270BHP @3,000rpm @90"hg
At 19,400, high blower water injection on... 1,860 BHP @3,000rpm @90"hg
400 rounds per gun, and an eight-gun pod could be fitted under the center section of the wing...
Base weight was 15,615, max was 24,864
The P-51H was a single engine P-82, not the reverse.
-
Originally posted by M.C.202
The P-51H was a single engine P-82, not the reverse.
Though not exactly accurate, it's a pretty intresting way of putting it.
-
Hi Tony,
>The MK 103 was a very powerful, long-range gun and the MG 151/15 was also superior to the .50 in power, but their combined rates of fire were much lower than the US armament. It would probably have come down to luck; the US plane would have scored more hits but the Do only had to connect once with that 30mm cannon.
By your own calculations, the two MG151/20 cannon alone had the same firepower as the Twin Mustang's six Brownings and the MK103 added almost twice the firepower again.
There is absolutely no contest - the Do 335's firepower was far superior to the P-82's.
If a battery can deliver the number of projectiles required for a certain probability of kill in a shorter period of time than another battery, it's superior. The absolute number of rounds is quite irrelevant. With about three times the firepower, the Do 335's battery is superior to the P-82's anywhere in effective range.
Luck has nothing to do with it.
Regards,
Henning (HoHun)
-
Originally posted by HoHun
Well, there should be a difference between the 1945 Merlin-powered P-82B and the late-1946 Allison-powered versions like the F-82G I listed above.
Differences are significant in that the F-82G was a night fighter, fitted with a large under-wing radar pod and its associated hardware.
Had the war in Europe continued on into 1946, the P-82B would have remained the primary varient, supplemented by the 487 mph P-51H. Indeed, had it appeared that the war would drag on that long, the Republic XP-72 would not have been cancelled. This monster, armed with with the proposed four 37mm guns (Republic's Chief Engineer has stated that the probable production armament would have been six Hispanos), would have been capable of level speeds right at 500 mph (both prototypes reached 490 mph on 450 less HP than the spec engine).
I view the Do 335 as being badly outclassed as a fighter, and being considrably slower than the Me 262, it would have been hard pressed to escape the newer generation of Allied piston-engine fighters using speed alone.
My regards,
Widewing
-
Hi Widewing,
>I view the Do 335 as being badly outclassed as a fighter, and being considrably slower than the Me 262, it would have been hard pressed to escape the newer generation of Allied piston-engine fighters using speed alone.
Well, that depends on the numerical ratio between Allied fighters and the Do 335s. Facing equal numbers, the Do 335 certainly would have been highly competetive.
By the end of 1945, the Do 335 would have been powered by the DB603LA with 1800 HP at 9 km altitude. By the time the P-72 would have been ready, the Do 335 probably would have been powered by the Jumo 222E/F.
>both prototypes reached 490 mph on 450 less HP than the spec engine).
The Do 335 prototype reached 482 mph in 1944. That was with the DB603A engines which had 700 less HP than the DB603LAs, and a full throttle height of 6 km compared to the DB603LA's 9 km.
>escape the newer generation of Allied piston-engine fighters using speed alone.
Hm. Speed is an essential offensive quality.
Regards,
Henning (HoHun)
-
Originally posted by HoHun
There is absolutely no contest - the Do 335's firepower was far superior to the P-82's.
If a battery can deliver the number of projectiles required for a certain probability of kill in a shorter period of time than another battery, it's superior. The absolute number of rounds is quite irrelevant. With about three times the firepower, the Do 335's battery is superior to the P-82's anywhere in effective range.
Luck has nothing to do with it.
I would entirely agree with you in the case of attacking large bombers which could soak up a lot of fire before going down. However, the .50 was generally adequate against fighters so the Do 335 might have been disabled by a few .50 hits, depending on where they landed. Sure the Do's armament was far more destructive, but against fighters the six .50s were probably destructive enough.
So if you could run a one-on-one combat between these armament fits a hundred times over, I would expect the Do to win most of them, but lose some on those occasions when the P-82 could land some .50 bullets in the right place - which is really down to luck.
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and Discussion forum (http://forums.delphiforums.com/autogun/messages/)
-
GRUNHERZ said:
Though not exactly accurate, it's a pretty intresting way of putting it.
By this I mean that the research and design put into the P-82 was the basis for much of the H model re-design.
It was the "clean sheet" that allowed for better (faster and cheaper) unit production, and incorporation of the latest drag studies.
I see the P-82 vs Do 335 question revolving on who sees who first. If Co-E and Co-alt, the better wing loading and the better range of vision (not counting the extra set of Mk1 eyeballs) of the P-82 would give it the edge.
As to the P-72, it was first flown in Feb of '44. The 490 mph "on the books" speed and the "500mph" run was with the four blade (rather than the planned six blade counter rotating one) prop was in '44.
I look at design and production dates to see what matches to what, rather than the "saw combat use" thing. This is a game using pre-Sept '45 aircraft out of their historic context, not a WWII re-creation. If it was re-creation only one of twenty pilots would be in "late" aircraft in combat, worse for the Axis birds.
-
Any P-82B speed chart :D ?
-
No P-82, but here`s one for the Do 335 w. different engines.
Also small note, the Do 335A`s "fighter" weight was 9010 kg, (not over that, or even 10t - that would include 500-1000kg extra bombload, too. Rare to see on fighter;) ) with full 1350 kg fuel etc.
That would give 234 kg/m2 wingloading. And I doubt the Mustang could outturn it, looking at the normal Mustang-FW 190A analogie, the Mustang had much lower wingloading there, too, but turn capabilities were equal; the laminar flow wing came at a prize: lower lift coefficients and bad stall characteristics ! I would think the same is true for the P-82, their turn characteristics mostl likely being more equal.
Here`s the Do335 speed chart.
[IMG]http://mitglied.lycos.de/luftwaffe1/do335/flugleistung.gifIMG]
It should be noted that the curves are for Kampfleistung, or Military power, actual max. powers are many hundred HP more, especially when water injection or NO2 injection is used.
W/o the Mach number taken into account, the following performance can be expected with DB 603 LA and water injection (2400HP at SL, 2200HP at 7200m):
At SL : 660 km/h, 23.5 m/sec climb rate
at 7.2km : 813 km/h, 16.5m/sec climb rate
Now, to add the top of that, I would like to mention my usual perversion :D , putting a DB 603 N into anything that flies.. but here it`s a real probability, the 603 N being an improved 603 LA in it`s details w. higher boost, re-designed cylinders etc.
Power output was 2750 HP at SL, rated altitude 11!! km, where it developed 1950 HP..
-
You can have all your silly P82, Do335 and P72..
I'll just take this one... :)
http://www.luft46.com/heinkel/hep1076.html
-
Hi Tony,
>Sure the Do's armament was far more destructive, but against fighters the six .50s were probably destructive enough.
More is better. The Do 335 has three times the firepower of the P-82, so it only needs a much smaller window of opportunity. Where the P-82 needs to track its target for 3 s to kill it, the Do 335 only needs to track it for 1 s. And when it comes to snapshots, they're much more destructive with 1 x 30 mm and 2 x 20 mm than they are with 6 x 12.7 mm.
>So if you could run a one-on-one combat between these armament fits a hundred times over, I would expect the Do to win most of them, but lose some on those occasions when the P-82 could land some .50 bullets in the right place - which is really down to luck.
There is bad luck and good luck. On other occasions, the Do 335 would fly on with a lot of .50 bullets in the wrong places. The law of large numbers says that the end result converges to the firepower ratio.
Regards,
Henning (HoHun)
-
At high altitudes, the 50 cal was superior to the 20mm. Why, you ask?
I have seen gun camera footage of a Mig15 being taken down at about 1200-1500 yards. The pilot commenting on the footage said (I'm trying to remember the quote as best I can)
"Korean War engagements were much different than in World War II. In World War II, we used to get very close, less than 300 yards, before firing. But when I got to Korea, [somebody] showed me that you could fire at very long ranges at high altitude. The air is much much thinner at 30,000 feet, and we were commonly shooting down aircraft at over 1000 yards"
Maybe somebody else saw this show too. I do believe it was talking about the M3 machine gun though.
-
Hi MC202,
>I see the P-82 vs Do 335 question revolving on who sees who first. If Co-E and Co-alt, the better wing loading and the better range of vision (not counting the extra set of Mk1 eyeballs) of the P-82 would give it the edge.
Well, all that tells us is that the Do 335 pilots would avoid a co-energy merge. Given any pair of opposing fighters, virtually always one would have the edge in a co-energy merge, but that doesn't tell us much about which fighter is better in an air battle.
>As to the P-72, it was first flown in Feb of '44. The 490 mph "on the books" speed and the "500mph" run was with the four blade (rather than the planned six blade counter rotating one) prop was in '44.
Generally, I don't expect much performance difference between a six-bladed propeller, but a significant improvement in flying qualities with the latter. It gave the XP-72 torque-free handling, which interestingly mirrors the Do 335's characteristics.
>If it was re-creation only one of twenty pilots would be in "late" aircraft in combat, worse for the Axis birds.
By that criterium, I could throw the Fw 190 prototypes into a Battle of Britain context, where they would make a rather extraterristian impression.
For a comparison of the airframe quality, you have to acknowledge the difference between operational and prototype airframes, and that performance is determined to a large degree by the engines which are improved continously.
It just depends on your specific intention :-)
Regards,
Henning (HoHun)
-
Hi Suntracker,
>At high altitudes, the 50 cal was superior to the 20mm. Why, you ask?
Well, contrary to that impression you ganied from that single case, the USAF in the Korean War was alarmed by the poor effectiveness of their 12.7 mm batteries and started a project to improve firepower by mounting 20 mm cannon to their Sabres (Project GUNVAL). Though the GUNVAL Sabres encountered some teething problems, the program was considered a success, and based on the GUNVAL experience the USAF switched to cannon armament for their fighters.
The Soviets had been using cannon from the beginning and considered them far superior to the USAF armament.
Regards,
Henning (HoHun)
-
Originally posted by M.C.202
By this I mean that the research and design put into the P-82 was the basis for much of the H model re-design.
It was the "clean sheet" that allowed for better (faster and cheaper) unit production, and incorporation of the latest drag studies.
Every authority on the P-51 that I have read states that the P-51H was a production series development of the XP-51F. Likewise, the XP-82 was proposed as combining two stretched P-51H fuselages with a common center section wing. The fact that P-51H series production was underway long before the two XP-82s had finished flight testing is reasonable evidence that this is correct.
For the record, the USAAF placed its order for the XP-51F prototypes on June 20th, 1943. First flight was in mid February of 1944. A contract for the XP-82 wasn't issued until January of 1944. This was just four weeks before the XP-51F roll-out. It would several months before North American even had the minimal engineering drawings to begin tooling for the XP-82, much less actual construction of the airframes. I think you can point to the XP-51J as a true comtemporary of the XP-82, and those two prototypes did serve as a test bed for the Allison V1710-119 installation and a later development of the V1710 eventually found its way into the P-82E.
My regards,
Widewing
-
Originally posted by HoHun
The Soviets had been using cannon from the beginning and considered them far superior to the USAF armament.
Regards,
Henning (HoHun)
Note also that the U.S. Navy had long switched over to the 20mm cannon as its standard air to air gun prior to the Korean conflict. It seems that the USAF was well behind the 8 ball in this regard.
My regards,
Widewing
-
I donīt want to be the pilot in the P-82 during a manoevering fight, sitting not in the center. Imagine how your body is shaken when you do a lot of rolling manoevers. Every pilot would get sick very quickly, for sure.
niklas
-
Hello, Ho Hun (boy that's a lot of H's)
Ho Hun said:
"Well, all that tells us is that the Do 335 pilots would avoid a co-energy merge. Given any pair of opposing fighters, virtually always one would have the edge in a co-energy merge, but that doesn't tell us much about which fighter is better in an air battle. "
Better in an air battle is saying better in any air battle, that is too broad a brush for me to use. Numbers and that day's mission plan add too many posibilities to count.
I see the following breakdown (given equal pilots):
If one sees the other first, combat can be avoided or a non plane based advantage can be set up, ie my P-40B drops down on your Ta152 from a 5,000 foot alt advantage before you see me. A stone axe from behind will kill.
Both are aware of each other, but one has a large advantage in E or placement. This is a bit like the above, but if one aircraft is much better at speed, climb, something important, the disadvantage can be overcome with time. This still gives a lot of advantage to the better placed aircraft.
Both aware, close to co-E, no position advantage. This is the fight that tells about the aircraft, not the set-up before the fight.
Ho Hun said:
"By that criterium, I could throw the Fw 190 prototypes into a Battle of Britain context, where they would make a rather extraterristian impression."
I did not make my self clear when I said "I look at design and production dates to see what matches to what matches to what..." We are closer than you might think. A prototype is not "in production" to me, it is a prototype.
No production line was ever built for the P-51F (darn it). It flew in late '43 so I will compare it to other one off's or very small production (say under 20 or so airframes) aircraft of that time frame.
In this game setting, Battle of Britain would only apply during a specific scenario context, not in the broader (more used) play areas. Are you sugesting use of a rotating aircraft introduction for the game with limits in % of aircraft type that can be used at any given time to match historic numbers? :)
I do on the other hand think that the P-51 H is a valid aircraft for the game, in full mass production with 555 total built and (I can't find the darn pre Aug '45 number) flying during the time span of the game. Perk it, don't let it into a historic scenario, but it does fit in with the ahistoric game combat nature that most fly in.
Were more P-51H's, P82's, or P-80's (not YP-80's) production line built and flown pre-Aug '45 or were more Do 335 's?
On the XP-72 prop thing, you could very well be right, I thought that the engine was "underpropped" for the speed the airframe was built for, but my math skills and training would not support my being an expert:)
I like non flame discussions on things like this. I learn things :)
-
Hi MC202,
>Better in an air battle is saying better in any air battle, that is too broad a brush for me to use.
Agreed! :-)
>I see the following breakdown (given equal pilots):
Well, your breakdown is not specific for the compared aircraft, so it doesn't bring out their relative strengths and weaknesses.
>Are you sugesting use of a rotating aircraft introduction for the game with limits in % of aircraft type that can be used at any given time to match historic numbers? :)
Great idea :-) I actually tried to set up something like that in an Air Warrior scenario, but the software messed it all up :-(
>Were more P-51H's, P82's, or P-80's (not YP-80's) production line built and flown pre-Aug '45 or were more Do 335 's?
Not sure about all of them, but I guess it were more Do 335s. For a fair comparison you should use VE day, not VJ day though.
>On the XP-72 prop thing, you could very well be right, I thought that the engine was "underpropped" for the speed the airframe was built for, but my math skills and training would not support my being an expert:)
Well, in my opinion, the actual reason with the XP-72 was that it used the same old 1930s' Seversky S3 wing section as the P-47, which wasn't that good at high Mach numbers. The P-47 ran into compressibility problems at Mach 0.73 , a speed that the much more powerful XP-72 could have reached in level flight.
It's probably not by accident that most post-war propeller fighters like the P-51H, F-82, Spiteful and Sea Fury had laminar flow wings with very good Mach behaviour. (The NACA 23 wings of the Fw 190, F8F and Do 335 seem to have been acceptable, too.)
>I like non flame discussions on things like this. I learn things :)
Yes, this one is a good one, I'm learning, too :-)
Regards,
Henning (HoHun)
-
Hi Widewing,
>Note also that the U.S. Navy had long switched over to the 20mm cannon as its standard air to air gun prior to the Korean conflict. It seems that the USAF was well behind the 8 ball in this regard.
Roger that! The Navy had actually been pushing for cannon even in WW2, with the USAAF promoting the 12.7 mm (and the 15 mm) machine guns. As a result, the Navy fighters were much better armed from the F8F on!
Regards,
Henning (HoHun)
-
And in case you haven't seen it, this is why the Americans made less use of the Hispano cannon in WW2 than they might have:
http://www.quarry.nildram.co.uk/US404.htm
Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and Discussion forum (http://forums.delphiforums.com/autogun/messages/)