P47 Climbrate - incorrect?

[mondego]

I'm reading the autobiography "Thunderbolt" by Robert Johnson, a top scoring ace in P47s. In the book he claims that once the P47 was equipped with a paddle blade, the P47 could outclimb a Spit9! Obviously this is not the case in game... anyone have any insight into this?

[EvlPrsn]

if the jug climbed even as good as a 51, i would fly it alot, its a very nice plane, but the climb just kills me.

[BaDkaRmA158Th]

That depends on the altitude, the 47 has the same power low or high, of course up higher you get less drag.
So maby if he was operating around 20-25+k he could indeed out climb the spit9 like he say's.

[Anaxogoras]

It's a good thing we can have confidence in that assessment, as fighter pilots have never been known to exaggerate the abilities of their aircraft.

<S> Mondego, you're a tough pilot.

[colmbo]

Johnson said the Jug would out zoom climb the Spit...not steady state climb.

[Serenity]

It's a good thing we can have confidence in that assessment, as fighter pilots have never been known to exaggerate the abilities of their aircraft.

<S> Mondego, you're a tough pilot.

That may be true, but the important thing is: This statement was made regarding a jug WITH paddle-blade props. Does ours have them too?

[Karnak]

That may be true, but the important thing is: This statement was made regarding a jug WITH paddle-blade props. Does ours have them too?

Other than the P-47D-11, yes.

[Serenity]

Other than the P-47D-11, yes.

Alright, cool, wasnt aware of that.

[mondego]

Johnson said the Jug would out zoom climb the Spit...not steady state climb.

That's what Johnson says earlier in the book, before the addition of the paddle prop. Later (page 240 of the paperback) he writes:

"But what a difference the blades made. At 8,000 feet I pulled the Thunderbolt into a steep climb. Normally she'd zoom quickly and then slow down, rapidly approaching a stall. But now - the Jug soared up like she'd gone crazy. Another Thunderbolt was in te air, and I pulled alongside signalling for a climb. I'm not an engineering officer, and I don't know the exact feet per minute that we climbed. But I left the other fighter behind as if he were standing still. The Jug stood on her tail and howled her way into the sky. Never again did a Fpcke-Wolfe FW-190 or a Messerschmitt Me-109 outclimb me in the Thunderbolt. The new prop was worth a 1000 horsepower more, and then some. Later I had the opportunity to mix it up with a Spit 9B, the same model fighter that had flashed me in a climb. This time the tables were reversed; I was astonished as we both poured our coal to our fighters, and the Thunderbolt just ran a way from the Spit."

When he mentions flying with the Spit9B, he doesn't reference the altitude unfortunately. However in his previous comparison with the Spit he was at 5000 feet. Regardless, the Spit 9 climbs better than the P47 at any altitude in game, in which case it raises an eye of suspicion.

Posted on: Yesterday at 10:38:20 PMPosted by: Anaxogoras 
Insert Quote
It's a good thing we can have confidence in that assessment, as fighter pilots have never been known to exaggerate the abilities of their aircraft.

<S> Mondego, you're a tough pilot.

This could very well be true! Thanks for the compliment too. :-)

[Furball]

http://www.spitfireperformance.com/spit9v109g.html

There were quite a few Spitfire IX versions, i suspect he means a Spitfire Vb as IX's were not as commonly known as IXb.

[Kweassa]

The new prop was worth a 1000 horsepower more

 This statement alone pretty much makes it evident that Johnson's no flight engineer.

 Exaggeration? Oh yes.


 

[Widewing]

Regardless, the Spit 9 climbs better than the P47 at any altitude in game, in which case it raises an eye of suspicion.

Ah, no it doesn't. You must consider where the P-47 was designed to fly and fight. Ideally, this is around 30,000 feet. Up there, it had no real competition in the Summer of 1943. However, let's limit altitude to 25,000 feet, which is well below the P-47's critical altitude and see how it compares to the Spitfires commonly in service at the time.

At 25k, the following climb rates were recorded using War Emergency Power:

Spitfire Mk.IX: 2,897 fpm
Spitfire Mk.XVI: 2,840 fpm (essentially, a Mk.IX LF)
Spitfire Mk.V: 1,654 fpm
P-47D-25: 2,622 fpm (heavier than Johnson's P-47D-5)
Fw 190A-5: 1,876 fpm
Bf 109G-6: 2,185 fpm

Note that the Fw 190 and Bf 109 aircraft contemporary to Johnson's combat tour cannot climb with the P-47 at 25k (not even at 22k), just as Johnson stated.

Added for effect:
P-47D-40: 2,798 fpm
P-47N: 3,038 fpm

Go up to 30k and the P-47D-25 climbs faster than the Spit IX.

Finally, there are factors that cannot be included in the game that are certainly relevant to this discussion. Bob Johnson was a friend of mine. His memory wasn't perfect, but I don't recall any penchant for exaggeration. Moreover, I find it distasteful for folks who play an online game as their reference to belittle a pilot who was considered by many to be the most talented fighter pilot to serve in the 8th Air Force.

Read what Johnson had to say to me, here: http://bbs.hitechcreations.com/smf/index.php/topic,27675.0.html

My regards,

Widewing

[RRAM]

Nice post Widewing.

I think the only german planes able in late '43 to equal the climbrates and accelerations of the P47s in the 8th AF were those 109G6 fitted with GM-1 and DB605ASM engine (larger supercharger compared with the standard DB605A engine), and they were only a handful flying in that period of time.

Certainly at extreme altitudes the US fighters were excellent.

However that test you did, was in game, I guess?. I ask it because when I looked for the climb charts of the P47D25 this is what I found:



The charts must be in an error then, as they list something around 2300fpm@25000 feet using WEP. I'm not surprised about it as most of the charts posted in the planes section of the main page must be a bit outdated after so many plane additions and ,probably, FM fixes.

One question, Widewing, as I've always wondered about it...which power outputs did the P47's R-2800 deliver at 20,25 and 30.000 feet?.

[Widewing]

The charts must be in an error then, as they list something around 2300fpm@25000 feet using WEP. I'm not surprised about it as most of the charts posted in the planes section of the main page must be a bit outdated after so many plane additions and ,probably, FM fixes.

One question, Widewing, as I've always wondered about it...which power outputs did the P47's R-2800 deliver at 20,25 and 30.000 feet?.

I tested at 25% fuel, standard ammo load (P-47s almost never carried the max ammo load we have in the game (added too much weight, diminished range accordingly). That's why all the fighters did better than the full load charts.

Let's check the power rating at altitude for the P-47D-25 with the earlier R-2800-59... 2,300 hp @ 31k (combat power) , and 2,000 hp @ 25k (MIL power). Beginning with the D-27, power rating of the -59 increased to 2,600 hp @ 25k (combat power) and 2,000 hp @ 25k (MIL power). All B series R-2800s in P-47s made 2,000 hp in MIL power from sea level up through critical altitude, which varied slightly depending upon the dash number of the engine (typically from 25k through 31k).

C series engines had a rating of 2,800 hp (combat power) and 2,100 hp (MIL power).

My regards,

Widewing

[RRAM]

Thanks for the power ratings, Widewing. No doubt the Jug was so excellent at high altitudes...those power outputs at that high altitudes are amazing for a WW2 plane ,much more if we keep in mid it was a mid war fighter.

I tested at 25% fuel, standard ammo load (P-47s almost never carried the max ammo load we have in the game (added too much weight, diminished range accordingly). That's why all the fighters did better than the full load charts.

Ahh, that explains the differences between the charts and your test. No discrepances between in game performance and them, then .


Thanks a lot, again.