DCS: P-47D-30 Discussion

[sobek]

This is not a one-dimensional problem. Whether or not your point is valid, you shouldn't always look at this from a 1v1 perspective.

[AdrianJ]

I see my post has been removed, if I have offended anyone then I apologize. I suppose it was a little childish, that wasn't my intent I just wanted to give some people a shake. What I really wanted to say is that if ED were developing my favorite second world war fighter I would trust them to simulate it as close as is humanly possible to the real aircraft, that after all is the reason I use DCS. If it wasn't as good as fighter a or b or c then I would try harder and have a lot more respect for the men and boys that really did fly it. After all there was not very often a second chance for them. It just becomes so boring always reading this aircraft should be this and this should be that, just use them and enjoy them.

[Krebs20]

Just wondering. What level of MP are we talking? Factory vs wartime mods? Octane fuel? Prop rpm, and 2800 dash number?

[Echo38]

Just wondering. What level of MP are we talking? Factory vs wartime mods? Octane fuel? Prop rpm, and 2800 dash number?

 

If it were up to me (which, of course, it isn't), we'd have commonly-used "middle-of-the-road" ratings—no extremes, but a reasonably close match for the opposition—rather than taking either the lowest (what our P-51D has now) or the highest (some of which aren't certain to have been commonly used in combat).

 

It's been about ten years since I was really into examining this stuff, so I don't remember the numbers for the the P-47, but what I do know is that each of the "Big Three" (P-38, P-47, and P-51) went through this, with the original boost rating out of the factory being relatively low, and then higher boost ratings authorized later in the war, often due to the availability of the higher-grade fuel. However, even when the better fuel wasn't available, higher ratings than the factory one were often used, increasing combat performance at the expense of engine life & reliability. For the P-38J & L, the factory setting was 60" @ 3000 RPM (~1600 hp.). Later, officially-authorized settings included 64" @ 3200 RPM (~1720 hp.) and 66" @ 3200 RPM (~1780 hp.); I don't remember for certain if the 70" @ 3200 RPM setting was officially authorized, but it was used. The highest I'm sure of is 66"; I have a scan of the document authorizing & recommending its use in combat, although I don't remember who gave it to me.

 

I'm attaching it to this post, along with everything else I have which is at all relevant (although I do not have all of the documents that I've seen scans of--yes, I'm kicking myself here, ten years later). Note that some of them are preliminary flight test reports, which doesn't necessarily mean that those ratings were used in combat, and others are merely engine tests, which may or may not have been performed "under load." Here's what I have. Unfortunately, I've never had the opportunity to visit an archive in person, or anything of the sort, so I relied on what other people have made available on the Internet. No idea now where some of these came from, although most of them are watermarked as being from Mike Williams's site. (There are eight files here; four PDF and four image files.)

supplymemo-11july44.pdf

ppf-20june44.pdf

24june44-progress-report.pdf

cti-1659.pdf

Edited March 3, 2015 by Echo38

[Zunzun]

As far as I know the 9th wasn´t given the 150 grade fuel. Only for the 8th. So although jug with higher grade would be historical most of the flying ones (the tactical air force´s) by late 44/45 were using the 130 grade (and normal boosts).

My main point in saying this (not that I am against a 8th AF on 150) is that it doesn´t change the way of fighting. The higher boost will not turn the 47 in a dogfighter. It still will have to fight on its own terms (B&Z) and the main benefit brought by the extra power will be that the exit window will be bigger.

I really think that a well flown 47, regardles of the fuel and boost used, will be very competitive. Specially if sound tactics are coupled with strong team playing.

[Echo38]

Unrelated to that discussion, but still may be useful to the development team:

Republic P-47D-30 Longitudinal Stability.pdf

[Echo38]

most of the flying ones (the tactical air force´s) by late 44/45 were using the 130 grade (and normal boosts).

 

Unfortunately, I don't have the document, but somewhere I've seen a memorandum authorizing slightly higher boosts (a few inches higher than factory, not as high as the latest ones) for the regular fuel. As I said before, even without the special higher-grade fuel, they sometimes set the engines to a higher WEP rating, and accepted that they were wearing the engines more, because the combat advantage was deemed worth it.

 

If anyone knows anything about this document, that'd be helpful. At this point, I'm feeling a little lost, because it was so many years ago, and I foolishly neglected to save many of these document scans that I saw on various web sites.

Edited March 3, 2015 by Echo38

[HeadHunter52]

The Jug will need to keep speed up in order to work the wing load.

It will need altitude in order to make a conversion to higher speeds for an escape. Said altitude depends on how much speed is to be recovered and how many trees he wishes to photograph as he flies by.

It is a bomb cart, not a fighter, not in the purest sense.

 

Allied fighter development was an effort to reach deep into Europe, serving as a strategic asset paired with four-engine bombers. The goal was to beat the Hun into a bloody mass on the ground. Dog fighting, in its most basic sense, is a tactical effort, and requires a different airplane. The mission requirements were different. The P-47 ad 51, and to a degree the 38, were tasked with a helluvalot more demands and had to be a compromise in great part. They did a lot of things which made individual tasks less than optimal.

 

As strategic support, they were clearly superior planes, as they helped make the bombing war possible -and won handily.

 

Our sim, here, does not model that, and as a result, the weaknesses of aircraft designed as strategic assets are magnified. It isn't just men an machines - it is the mission they undertake that makes history.

[Zunzun]

It is a bomb cart, not a fighter, not in the purest sense.

 

I disagree. It was a fighter in the purest sense indeed. It didn´t fight in the same way most people think of. It wasn´t a dogfighter and relied on team work heavely but it still brought down the enemy planes in big figures as the spitfire, the yak3 the La or the mustang did.

 

It didn´t have the power loading/wing loading to mix up in 1vs1 co energy with either 109/190 at low altitude but at altitude or in the B&Z style at low altitude was a pure fighter. It had the bonus of turning up being a superb jabo.

[Echo38]

The P-38, too, was initially intended to be a fighter. Not a bomber interceptor, as often is claimed, nor a multi-role combat aircraft, but a long-range fighter. That was the express desire of those who initiated its creation & those who designed it. It just so happened to be, by nature of its power and structural strength, suitable for carrying heavy ordnance for ground attack as well, which it was used for, at length, after the Luftwaffe was largely defeated.

[Friedrich-4B]

Unfortunately, I don't have the document, but somewhere I've seen a memorandum authorizing slightly higher boosts (a few inches higher than factory, not as high as the latest ones) for the regular fuel. As I said before, even without the special higher-grade fuel, they sometimes set the engines to a higher WEP rating, and accepted that they were wearing the engines more, because the combat advantage was deemed worth it.

 

If anyone knows anything about this document, that'd be helpful. At this point, I'm feeling a little lost, because it was so many years ago, and I foolishly neglected to save many of these document scans that I saw on various web sites.

 

Sounds familiar, but I can't remember where I have read that - it might have been in Warren Bodie's book on the P-47, or Graham White's on the R-2800. I don't have time to look now, but I'll see what I can find.

[Echo38]

I have Bodie's The Lockheed P-38 Lightning, but not his P-47 one. Maybe the former is where I found the info. Perhaps I'll go hunting for it later.

[Krebs20]

I think we can expect 100/130 octane fuel. The last document echo linked, it calls for the used of 150 kits to no longer be supplied to p47s as it was no longer needed.

WEP at 65 with 150 gas looks to be possible.

I have worked on later dash number 2800s. Putting that much MP into a 2800 will break things. You will go from a healthy engine to one that will have only hours of useful life remaining. Cracked heads, scorched pistons, ring lan failures, dropped valves, blown heads. Funny, I have seen an engine will all of the above and the crew complained it was a little rough. (Over boosted event) We are talking major maintence after an event at this pressure. However, if it means the plane comes home, then it was worth it.

[Krebs20]

And a side note. Let try to limit the straight engine talk. I love p38s and p51s. But fancy liquid cooled wimpy inline engines cannot be discussed in the same context as round engines.

[Echo38]

Gotta admit, despite the P-38 being my favorite airplane, the Double Wasp is my favorite engine. Specifically, the one in the Hellcat sounds so wonderful. Jeff Ethell said that the reason the R-2800 in the F6F sounds different than the ones in the P-47 and F4U was that the F6F had irregularly-spaced exhaust stacks. However it works, it works!

[Merlin-27]

Sounds familiar, but I can't remember where I have read that - it might have been in Warren Bodie's book on the P-47, or Graham White's on the R-2800. I don't have time to look now, but I'll see what I can find.

 

White's book is great.

 

I loved reading about Frank Walker and his work with the 2800. With the help of anti-detonation injection he was able to run one in a test cell at 150 in. Hg / 3800 hp. That's one incredibly tough engine. He was also known to conduct test runs of the R-2800 @ 3000 hp for 100 hours!

 

I wonder if a possible compromise to the octane dilemma is the inclusion of ADI as a field mod.

[Merlin-27]

Just wondering. What level of MP are we talking? Factory vs wartime mods? Octane fuel? Prop rpm, and 2800 dash number?

 

Should be the R-2800-59 if it is a factory powerplant for the P-47D-30-RE

 

2000 hp @ 2700 rpm @ 1500 ft

2000 hp @ 2500 rpm @ 25,000 ft + turbosupercharger

 

*2300 hp with water injection (ADI) mod

[HeadHunter52]

I disagree. It was a fighter in the purest sense indeed. It didn´t fight in the same way most people think of. It wasn´t a dogfighter and relied on team work heavely but it still brought down the enemy planes in big figures as the spitfire, the yak3 the La or the mustang did.

 

It didn´t have the power loading/wing loading to mix up in 1vs1 co energy with either 109/190 at low altitude but at altitude or in the B&Z style at low altitude was a pure fighter. It had the bonus of turning up being a superb jabo.

 

1 on 1 is the purest definition of a dogfight, not the fur-ball. The Jug doesn't have the ability to "mix it up". Can it kill? Hell yes, but it needs an advantage at the outset, or it will be outmaneuvered and hit.

 

Killing the enemy with superior numbers or a start advantage doesn't make it a dogfighter.

[Zunzun]

1 on 1 is the purest definition of a dogfight, not the fur-ball. The Jug doesn't have the ability to "mix it up". Can it kill? Hell yes, but it needs an advantage at the outset, or it will be outmaneuvered and hit.

 

Killing the enemy with superior numbers or a start advantage doesn't make it a dogfighter.

 

Well maybe there was a bit of misunderstunding. I responded to your affirmation

 

It is a bomb cart, not a fighter, not in the purest sense

 

If I read again my answer carefully, it did said:

I disagree. It was a fighter in the purest sense indeed. It didn´t fight in the same way most people think of. It wasn´t a dogfighter and relied on team work heavely but it still brought down the enemy planes in big figures as the spitfire, the yak3 the La or the mustang did.

 

So I am still affirm that the P-47 is a fighter in the purest sense.

 

From the wikipedia: "A fighter aircraft is a military aircraft designed primarily for air-to-air combat against other aircraf"

The thunderbolt was designed as an interceptor (a2a combat) then fullfilled the role of bomber escort (a2a combat) and only after hindered by relatively short range (for what it was needed) found its niche as a jabo.

[saburo_cz]

engine power probably should be 2535bhp, 2700rpm and 64inHG with 100/130fuel and water injection

 

according therse reports

[Zunzun]

+1

Those are the figures I´ve seen most commonly on the -59 engines on latest Ds. Something between 2430-2600HP.

[Solty]

About 150grade fuel:

http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html

P-47D permission for 70 inches manifold pressure.

http://www.wwiiaircraftperformance.org/150grade/P-47-70inches-24june44.jpg

Tests of P-47D with 44-1 (150 grade fuel)

Speed

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-level.jpg

ROC:

http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-climb.jpg

 

This prooves the plane should fly on 150octane, as any other Allied plane in the game. They will have to fight Me262 in the future, so we need the 150octane. It is also realistc. Here:

 

" It can be operated at 70.0" Hg., 2700 RPM with water injection with 44-1 fuel. Climbs at high power must be limited because of high cylinder head temperatures and carburetor air temperatures. Short climbs can be made without dificulty."

 

+1

Those are the figures I´ve seen most commonly on the -59 engines on latest Ds. Something between 2430-2600HP.

Why P-47D needs to be common if Fw190D9 is flying with gyro sight and MW50 instalation even though most D9s flew with B4 and just C3 fuel without MW50? Germans have 109K4, it also is not a common plane for 1944 and yet it is in game.

 

This prooves that P-47D Thunderbolt should get the 150octane to match those planes in combat.:)

Edited March 4, 2015 by Solty

[saburo_cz]

Again 150 octane fuel, oh no... :(

 

2600 D-30 were produced, how many of them were used by 8th AF (ONLY ONE unit which used 150 grade fuel!!!)?

Because D-30 reached units during late 44, we can suppose only handful of them...

 

So, 100/130 fuel will be right!

end

[Kurfürst]

most D9s flew with B4 and just C3 fuel without MW50? Germans have 109K4, it also is not a common plane for 1944 and yet it is in game.

 

There were some 1600 K-4s and iirc 1800 D-9s produced, yet we still try to argue how 'uncommon' they were, huh? That's more than all the D-30s if saburos numbers are correct.

 

Apparently, that one unit of P-47s may have been running on high grade with the 8th AAF, all others running with low grade in the 9th AAF - and so suddenly the logic and standard turns upside down and its that we need the high grade variant for whatever reason.. Given the evidence, a good case could be made for the P-51D for higher grade fuels but quite obviously that's not the case for the P-47D. Or another I shall not mention.

Edited March 4, 2015 by Kurfürst

[Crumpp]

engine power probably should be 2535bhp, 2700rpm and 64inHG with 100/130fuel and water injection

 

according therse reports

 

That is what it should be to model the most common variant! Good find.