P-47N Thunderbolt vs. F4U-4 Corsair - Which was superior?

[lesofprimus]

Yep...

[Gnomey]

That it has Alder...

[Sal Monella]

Jon, I would in fact agree with you that if we were comparing the P-51D against the P-47N, it would be a fair comparison to load each up with an equivalent fuel level to carry each plane the same distance.

In keeping with this logic, we would not start the P-47 "D" and "N" models at 50% fuel for the same reasons I have already explained. The internal fuel capacity of the N is truly massive. In fact, the P-47N needs only 64% of it's internal fuel capacity filled to equal the same fuel load that a P-47D would have with 100% if it's internal fuel capacity. Thus, lowering each aircraft's internal fuel load from 100% which is what you started with to 50% which is what you are now advocating is merely a restatement of the same problem on a different scale.

See Davidicus' post of June 18, 2005 on page two of the thread linked below. He took his data directly from Republic Aviation performance manuals.

http://www.ww2aircraft.net/forum/vie...asc&star t=20

[JonJGoldberg]

Reply to Sal Monella >>>

Thanks for the lead. I followed the jousting for a while, but disagree with the tact. I understand your point, but find it seriously flawed:

(1) In order to argue with you, & possibly all the members here on this issue, I would 1st have to concede that your point, of putting in only the amount of fuel, & bullets required for our mock combat, to be a valid one. I do not, but let’s go with it for a moment… In all the bantering back & forth about the ‘exact’ data, & how much fuel is actually required, everyone is forgetting that these aircraft were designed to perform at somewhere between combat & normal weights (to my discovery recently as well; you see for the 1st iteration of my tables I used data of empty aircraft to generate performance figures, until Cheddar Cheese asked what happens when the pane is loaded…). By the numbers, at sea level a P-47N @ 50% fuel from Combat weight, is at its Max Designed Performance Weight. With less than that amount of fuel, the gained performance in turn & roll rates are beyond the abilities of the airframe; period. See a very much simplified Chart 1. So although my 50% fuel from Combat weight seems arbitrary, in fact, as shown in Chart 1, applying 50% fuel from Combat weight for each aircraft does not simply reduce the scale of the difference, it should, in general, bring all aircraft, during this era, give or take, within their optimal performance window.

(2) Since we agree my argument is valid with regard to a P-51D Vs a ‘47N, I offer another twist… To compound: suppose that I now change the aircraft to a P-51D, & a ‘47D. How do you apply your rule? My offer stays the same. From combat weight, change the fuel to 50%. Why does your rule change from comparison to comparison, and mine remains consistent? …I know, because I’m consistently wrong. Look forward to your reply.

[JonJGoldberg]

By the way, my fighter tables can be found here >>> http://www.ww2aircraft.net/forum/vie...sc&start =460

& I Have A Typo on Chart 1; the Magenta Bar, which should read 'Vne Max Speed Limit'.

[Sal Monella]

Jon,

Huh? I have no idea where the data in "Chart 1" came from. But here's another chart which I have aptly entitled "Chart 2".
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Chart 2

Jon is wrong

Sal is right.
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As you can clearly see from the chart I have provided above, you are quite wrong.

As to your second point, both of our comparisons are in fact constant. Yours uses the constant of either (1) full 100% internal fuel load or (2) 50% internal fuel load while mine uses the constant of (1) equal range which imposes the fuel load.

You said that, "Why does your rule change from comparison to comparison, and mine remains consistent?"

How is it that yours is a "constant" while mine is not? (Yours in fact involves a different fuel load for each aircraft as well as each aircraft will have a different internal fuel capacity.) Both of ours use a "constant" mathematical formula to determine fuel loads. Yours uses 100% internal or 50% internal capacity even though the capacities between aircraft vary considerably. Mine uses a "constant" mathematical formula based on range where the respective fuel loads are determined by that range.

How is my "rule" as you say, changing? Impose an equal range limitation on each, fuel up each aircraft to meet that range requirement and that's the fuel load.

Otherwise, you have a situation where in a comparison between a short range interceptor with a very small internal fuel capacity and a long range interceptor with a large fuel capacity, the short range interceptor will always appear to have a tremendous advantage in performance even though when they meet, each might very well be carrying the same fuel load because the long range interceptor had to fly a long distance to the area where the short range interceptor is still operating with a full tank. The actual performance between these adversaries at that point might very well favor the long range interceptor because it has shed much of its fuel load and weight.

The disagreement between us Jon is really quite simple. You believe it is more fair to impose an equal percentage of internal fuel capacity while I believe it is fair to impose an internal fuel capacity based on equal range.

In it's internal tanks, the P-47N literally has the capacity to carry an additional 2,500lbs of gas than a P-47D carries. Under your "rule" with the information you presented in your earlier post, the climb rate of the "D" is equal to the "N" with the "N" carrying an additional 2,500lbs of fuel. (For a mental illustration of just how debilitating an extra 2,500lbs can be, imagine what would happen to the climb rate of the "D" if you added a 2,500lb bomb load in addition to having its tanks topped off.)

Anyway, you and I have a difference of opinion on this and that's OK.

[CurzonDax]

One thing on all of this, when it comes to air to air victories, one can only make the comparison in the PTO. In the ETO the Corsair never engaged the Luftwaffe in combat.

:{)

[elmilitaro]

The P-47 because of ...everything it had and did.

[JonJGoldberg]

Reply to Sal Monella >>>

I left the door open to you for something a bit more creative…
You seem not able to understand the chart, &/or question its validity & origin even though the ‘how-s’ & ‘where-s’ are visible, I drafted it; sorry it messed you up so… Surprisingly great response, your Chart 2; I knew when I wrote the last post, you would answer this way. Look back at it; in the 2nd & 3rd to last lines I wrote > “Why does your rule change from comparison to comparison, and mine remains consistent? …I know, because I’m consistently wrong." <

I’ll respond to the second part, as a last ditch effort, but concede, once again, in advance that I’m always wrong…

You wrote >"How is it that yours is a "constant" while mine is not? (Yours in fact involves a different fuel load for each aircraft as well as each aircraft will have a different internal fuel capacity.) Both of ours use a "constant" mathematical formula to determine fuel loads. Yours uses 100% internal or 50% internal capacity even though the capacities between aircraft vary considerably. Mine uses a "constant" mathematical formula based on range where the respective fuel loads are determined by that range." <

The instrument of my calculation can be found on every aircraft. It’s called a fuel gage. …Funny that each aircraft’s fuel gage, regardless of type or subtype under ‘comparison’ knows where to find my ‘set point’ without using a ‘formula’. That’s what I call consistent! Sal, you are ‘consistently’ using an ever changing mathematical formula you label constant… Riddle me this Batman… At what ‘constant’ speed are you determining this range; change planes is there a new ‘consistent’ speed; at what ‘constant’ height; what’s the ‘constant’ weather like, what if I have to go around a storm; do we fly together, or meet in the middle… I could continue… But I’ll end this way… I’ve yet to see your gage, what do you call it?

Another hint of truth... I don't want to fly around, I just want to dogfight. How do I do this your way... I know, fuel up with 200 miles worth of god only knows at what speed, height, fuel. If you run out of gas, press reset.

Glad we can agree to disagree.
Thanks for your time.

[evangilder]

While your efforts to try an quantify some magical formula to determine some aircraft better than another are interesting, there are things that just cannot be quantified with charts and graphs. To arrive at a definite answer is highly improbable.

Remember quite some time back, you accused me of romancing the stats and not looking at the facts? Isn't this kind of what you are trying to do with these tables? Yes, it is good information to compare, but when it all comes down to brass tacks, there is no formula to determine one WWII aircraft better than another.

[JonJGoldberg]

Finally, sombody is seing something!!!!! You are 100% correct, in my opinion. I created these tables, simply to clarify this issue of 'stats' vs 'history' as it were. My argument, that the canditate should be judged according to history still remains, & I put them in the 'blue box'. They are indeed just stats, & further, my twist on those stats (not that I pre-judged the outcome, just how I assembled the weighting of them, & combined thier gun performance with the flight performance). Thank you for finally realizing. Believe me I hope you all find them useful, as they indeed contain a lage amount of very hard to find data; this is why I left the math cells visible.

Good call.

[Sal Monella]

Jon, my "Chart 2" was an illustrative demonstration that charts don't mean jack ****. I too am sorry that my chart messed you up, or, should I say, just messed with you.

Where did you get your raw data from for the P-47? As you are well aware, garbage in, garbage out. Regardless of your points about the ease of just pegging the fuel tank at full or half, I am convinced that comparing the "D" and "N" models in such a fashion isn't a fair comparison due to the extra 2,500lbs of fuel carried by what is essentially a high performance version of the same aircraft

Turning to the data that populates yourt charts, again, where does this data come from? How did you arrive at the figures you are listing?

I have a bunch of specifications published by Republic Aviation and official Technical Orders that frankly differ from the data you have presented.

I don't have the time to go through all of the errors that literally litter your tables. For instance, your listed "combat weight" and initial climb for the P-47N-25 are WRONG. (And I will go with Republic Aviation's published data over whatever source you are relying on Bubb.) And where the hell exactly did you get data for your various turning speed data?

The "combat weight" is actually 16,330lbs.

The climb rate at 5,000ft ("combat weight") is 2,950 fpm. Sea level would be higher. (72" HG)

Top speed at critical altitude (32,000ft) is 453mph. ("combat weight" and 72" HG)

Like I said Jon, garbage in, garbage out.

You are apparently focused on developing relative performance values for some kind of sim. We've all played sim games that bend the envelope in unrealistic ways. That's how it happens Jon. Bad data into the computer and unrealistic performance in the sim. Time to put down the greasy joystick and read some big boy books.

By the way, just to show that there are no hard feelings, I'd be glad to correct your data for you. Just ask - nicely.

[JonJGoldberg]

You know, before I start, everything with you is where does your data come from. I post where it comes from all the time. I have nothing to hide… However, once again Sal, for you, I’ll go backwards…

47D-23 Prop & Climb:

http://www.xs4all.nl/~fbonne/warbird....html#repup471
Although specifically for D-22 (This site asks that nothing be reprinted) some climb rate Specs.

http://home.att.net/~jbaugher1/p47_4.html
Joe puts the climb rate at 2750ft/min, but >>> “Beginning with production blocks D-22-RE and D-23-RA, a larger (13- foot diameter) paddle-bladed propeller (either a Hamilton Standard Hydromatic 24E50-65 or a Curtiss Electric C542S) was fitted to make full use of the additional power provided by water injection. It added 400 feet per minute to the climb rate, but during landings and takeoffs there was only a scant six inches of clearance between blade tips and the ground. Takeoffs and landings must have both been hair-raising.”

http://www.cradleofaviation.org/hist...ft/p-47/7.html
From what must be a ‘Sal’ approved site, as you sent me here >>> “Many of the Fighter Groups flying the P-47 in June of '44 were still flying some of the older "razor back" models with the framed canopy. These included the ultimate "razor back", the P-47D-23-RA. This Evansville built fighter was equipped with the latest Curtiss Electric paddle blade propeller. Of all the D models, this one was the fastest and best climbing.”


These are but a few for the prop & climb thing; at least ones that *ucked up Einstein can give you instant gratification for (You must have edited all of this from your post, as these refrences are now missing; good catch).

The N stats:

Maybe I should not have mentioned the Cradle of Aviation, your referenced site, this is also from your referenced article >>> “J model was an especially good climbing fighter too. It had a climb rate at sea level of 4,900 fpm. At 20,000 feet, it was still rocketing up at 4,400 fpm, and got there in 4 minutes, 15 seconds.”

http://www.xs4all.nl/~fbonne/warbird....html#repup471
See the section on the N variant.

http://home.att.net/~jbaugher1/p47_13.html
Performance of the P-47N-5-RE included a maximum speed of 397 mph at 10,000 feet, 448 mph at at 25,000 feet, and 460 mph at 30,000 feet. Initial climb rate was 2770 feet per minute at 5000 feet and 2550 feet per minute at 20,000 feet. Range (clean) was 800 miles at 10,000 feet. Armament included six or eight 0.50-inch machine guns with 500 rpg and two 1000-lb or three 500-lb bombs or ten 5-inch rockets. Weights were 11,000 pounds empty, 16,300 pounds normal loaded, and 20,700 pounds maximum. Dimension were wingspan 42 feet 7 inches, length 36 feet 4 inches, height 14 feet 7 inches, and wing area 322 square feet.

I grow very bored reproducing data for you, especially since some of it is dead on in one place & not in others. This problem is I feel going to be like the 2” debate... All data that I used on the tables within my tables are as accurate as I could find, & seem acceptable to all but you. Wmaxt & Jabberwocky had some issues, as they are Lighting nuts, as you seem to be a ‘Bolt nut, but they are in agreement that my data is close enough; not that Lighting info has anything to do with ‘Bolt info.

As for the turn data: There is no turn data available, that I know of, and yes, in this regard, ever since I bought CFS-2 (199 I’ve been trying to acquire as much turn data as possible to implement within that sim, for my own enjoyment, & a few screen shots.

Jerry Beckwith is the author of the Flight Dynamics Workbook, the spread sheet I use to create the turn performance data with. The sheet is available @ www.netwings.org, as it says in the flight performance tables, & Chart 1.
From the Workbook >>
The Flight Dynamics Workbook has been designed to create flight models with accurate speeds, climb, roll, and turn rates. The Flight Dynamics Workbook automatically calculates air file parameters using the physical dimensions and performance characteristics of the original aircraft. The Workbook uses NACA wind tunnel data to calculate lift and drag parameters for the airfoils. The engineering data and formulas used to calculate propeller efficiency, climb rates, roll rates, and stability parameters were drawn from the NACA database as well.
The underlying principle of the Flight Dynamics Workbook is to calculate air file parameters based on the physical characteristics of the real aircraft. The following paragraphs describe the degree of accuracy can you expect from the Flight Dynamics Workbook.
Speed at Altitude
The maximum speed at sea-level and maximum speed at high altitude will be within 1% of the performance figures entered in the worksheets. The maximum airspeed will occur at the correct altitude, and the airspeed at any other altitude will be less than the maximum speed.
Climb Rate
The climb rate will be within 1% of the performance figures entered in the worksheets. Climb rate measurements depend on initial altitude and airspeed, test weight, time measurement interval, and pilot skill; results can vary significantly from test to test.
Roll Rates
The maximum roll rate will be within a few percentage points of the specified roll rate and the speed where the optimum roll rate occurs will likewise be within a few percentage points of the target speed. The same can be said for the measured roll rate at other airspeeds as well. Roll rate performance depends not only on altitude, but also on the aircraft's angle of attack; so pilot skill has a significant impact on test measurements. Roll rate is very difficult to measure accurately; test results will vary significantly from test to test.
Turn rates
The Flight Dynamics Workbook calculates turn performance in terms of g-force vs airspeed - which tells you how fast you can go without stalling, turn rate in degrees per second vs airspeed and minimum turn radius vs airspeed.
Lift coefficients, weight, and wing surface area are used to predict potential and predicted actual turn performance. The performance of properly tuned flight models will match the Workbook's predictions.
Actual turn performance data for WWII vintage aircraft is very difficult to obtain. To date, turn performance data for only one aircraft has been located, the P-51D. This data was within 5% of the performance calculated by the Workbook.

Back to my own words. I modify his results some-what, but this can not be done within his workbook, instead, I modify the results in my own Excel spread sheet. You are quite right with regard to junk in > junk out, so yes I would be interested, in actual numbers, if you have them. I will insert you as a source, as I did with Jabberwocky, or if like some info from I do not agree with, I will note them within the tables, such as the two that now exist.

[JonJGoldberg]

Reply to Sal Monella >>>
I finally found the stuff that was cut from the best fighter thread, that I had posted about sims... Look here http://www.ww2aircraft.net/forum/abo...0-asc-120.html

[CurzonDax]

Agreed on this info. In my experience a sim is just that, a sim. You can sim sim sim but it will not take over from actually flying these aircraft. The Corsair for example was not an easy plane and a sim just does not compare. I don't think the sims are probable, they are a sim. It is am imitation and a imitiation is not reality. Therefore comparing the performance of an aircraft reality vs. sim is incorrect and historically inacurrate.

:{)