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

[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".
--------------------
Chart 2

Jon is wrong

Sal is right.
--------------------

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 shit. 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/warbirds/ww2htmls/repup47.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/history/aircraft/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/warbirds/ww2htmls/repup47.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 (1998) 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/about3084-0-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.

:{)

 

[wmaxt]

John has tried to quantify the data from 20+ aircraft into a model that can be compared. Jon has tried to keep it as accurate as possible. Many /most of us havs stuck to one or a few aircraft simply because we can't cover them all, Jon, has given us a starting point.

The point I found most interesting is how close the top 10/12 aircraft were (not including the P-47N which had limited contact with most of the top 12).

In his comparison the P-51 was 8th, add tactics, training, and numbers and it was very effective in the ETO, showing how much more beyond the chart there is to consider.

As for sims, I think you may be confusing the sim experiance to the accuracy of the sim model. no they aren't reality but as Jon pointed out sims can accurately quantify the performance envelope of any aircraft. On the other hand a creative pilot can expand that envelope from there.

wmaxt

 

[Jank]

This disagreement that has come up is nteresting. Reading back I see that it began when Mr. Goldberg said that the P-47D-25 would be a better match against the F4U-4 than the P-47N.

I for one am not convincved.

 

[JonJGoldberg]

Reply to Wmaxt >>>

Thanks for your continued support. I'm having a little trouble understanding your reference to the '47N in the 2nd paragraph though.

I've just had time to go through the accident reports you set me a while back; you should repost the link. Seriously eye opening; GRRRREAT stuff!! Maybe the Lighting wasn't as expensive as I originally thought. I wish data like this was available for all aircraft in the tables; I'd work on figuring out how to include this info...

Reply to Jank >>>

Believe it or not, for the most part I was enjoying the fencing, but unfortunately, somehow, for me it was the post of Chart 2, as for my part maybe it was my reply to Chart 2, words started to be directed to the individual/s, as opposed to the topic/s… Although entertaining for you, as for my part I apologize for the personal remarks.

I had posted the following, with regard to the D Vs the N > "In reality the N indeed defeats the D. In my tables N indeed defeats the D. But we are not talking reality here, as the two never fought (F4U vs. P47, or P47vs P47). So I'm taking this posture, D as opposed to N, for the following reasons... @ combat weight, on production versions, the D's superior turning rate climb combined with it's level stall characteristic on my personal dogfighting scale, defeats the D's roll speed advantage." <

I made a typo, the last words should have said, …@ combat weight, on production versions, the D's superior turning rate climb combined with it's level stall characteristic on my personal dogfighting scale, defeats the N's roll speed advantage."
Now since you need convincing… I'll expand:

1st I need to qualify something… I'm not a pilot. I served in the USAF as a sheet metal mechanic, took flight lessons then (1980), and rode in the trainee's seat a few times in T-38s, but never got a license, they say I'm color blind. Now, at 45, the closest I've come, I'll ever come to dogfighting for 'real', like most (obviously not all) of us, admitted or not, is in a sim. You read my sim post, I imagine, so you know I know the sim is not real (I like to think it is at times), but like these letters I've combined into words, using them in a manner that allows a simulation of talking with you, I've tried for years to make the aircraft respond as they would, this is not to say that they are indeed real, much like the fact that you can not hear the cadence of my speech; however to me, the meaning of the 'stat' is portrayed in a much more convincing manner than simply the numbers, stats, figures, 'unanimated' staring back at me on a piece of paper, or screen. Perhaps we may all accept, one day, that a sim, like a video is not real, like these words, any words are not 'real', but they all can, when properly used, do a dam good job of helping us understand what happened/s in reality. Finally…

OK the promised expansion… I imagine the 'meeting' of the contestants, the '47? F4U-4 to be one on one, a dogfight, as a joust between the two is a draw, or at best, luck. Accepting the dogfight scenario (simulation), low speed attributes outweigh high speed attributes. I consistently read that WW2 dogfights happened at speeds centered around 200 to 250, depending on the year, combatants. This is not to say that the initial contact was made at that speed, only that the ensuing dogfight happened at that speed. No matter the praise each advocate has for their respective mounts, no actual WW2 Corsair pilot, no T-bolt pilot has said in print that their plane was a dogfighter, at least not one I have seen; with the exception of an article I found at (http://home.att.net/~historyzone/F4U-4.html), written in praise of the F4U-4, which says it was indeed amongst the best dogfighters of the era. At these speeds, the N no longer has a 'speed advantage'. The N's semi-laminar flow wings perform best at speeds above 250, and without these high speeds, it's performance decays faster than the D's decay. I know that some question my tables, but for now, it's the only document we all can have, check it out. http://www.ww2aircraft.net/forum/viewtopic.php?t=962&start=520

 

[DerAdlerIstGelandet]

Interesting conclusions there. I have enjoyed reading all of this. I have not said much because I am just trying to take it all in. Seriously very interesting stuff, all of you.

 

[syscom3]

It certeinly is an eye opener to see the info.

I salute Mr Goldberg for actually trying to quantify what plane is best. Plus there is a lot of constructive arguments coming from several people to keep the topic on course.

This is almost like seeing a thesis being generated by a student then dissected by experts.

 

[DerAdlerIstGelandet]

Yes I agree with you. At the same time though I do not believe that charts, graphs, numbers, and sims can accuratly tell you what aircraft was the best.

 

[FLYBOYJ]

Yep- Mr. Goldberg I commend you!

 

[Sal Monella]

Jon,

When I keep saying, "Where did you get your data?", I am really making a point like, "Did you pull that out of your rectum?" or Did you just plug in "P-47" into your web search engine and write down what came up?"

Garbage in, garbage out. You will notice that the various websites you have cited to are inconsistent with each other and at variance with the data I have provided below.

We still disagree on comparing the combat weight P-47N against the combat weight P-47D-25 or any other "D" model for that matter as the P-47N is carrying an additional 2,500lbs of fuel over the D-25's capacity. The D-23, by the way, had an internal fuel capacity that was 100 gallons less than the D-25 so there was an even greater fuel differential between the "N" and D-23.

I erased that comment about the D-23 not having the paddle blades because I remembered that I was wrong. Your data on the climb rate of the D-23, however is still in error, It was 2,920fpm. It had a greater climb rate than the D-25 because the D-25 was burdened with an extra 100 gallons of fuel in its internal tanks.

At any rate, in the interest of accurate information, I invite you to modify your charts to reflect the following where appropriate, or to take notice where the outputs from your data does not reflect the facts in the following data.

Wing area is 322.7sqft. ("D" model is 300sqft)
Length is 36'3-1/4"
Wingspan is 42'8"
Height is 13'7"

The total aileron area is greater than the "D" by 2.27sqft ("D" model is 25.7sqft)
The total wing flap area is greater than the "D" by 6.4sqft. ("D" model is 39.6sqft)

Empty weight is 10,998lbs. Combat weight is 16,330lbs. (Yes, those number are correct. Hopefully, you can see my point now.) Maximum takeoff weight is 21,198lbs. If we were to load up the "N" with the same internal fuel load as the D-25 model, it would weigh 13,850lbs.

Top speed at 32,000ft at combat weight and 72" HG is 453mph. The "N" can in fact do 467mph, just not while carrying a full internal fuel laod. The 467mph figure that is widely referenced is with an internal fuel load equivalent to the D-25 (100 gallons greater than the D-23). At 5,000ft, at combat weight and 72" HG, she can do 371mph.

The climb rate for the "N" at combat weight (16,330lbs) at 5,000ft and 72" HG is 2,950fpm. This is no small feat. The P-47M with a full internal fuel load (equivalent to the D-25) weighs just 13,275lbs. It can pull 3,775fpm at 5,000ft and 72" HG.

If the P-47N were to be loaded up with a fuel load equal to the "M" and D-25 (100 gallons greater than the D-23), I have no doubt that it would climb at 3,650fpm as it would weigh just 575lbs more than the "M" and has a greater wing area.

The "N" at a fuel load equivalent to the "D-25" would out turn any "D" model as it has a significantly more powerful 2,800hp engine and a greater wing and control surface area. The D-25, in combat weight, weighed in at 14,247lbs which is heavier than the "N" model with the same ammunition and fuel load (13,850lbs.)

Lastly, here is a tidbit that I would venture no one on this board is aware. The "N" model was designed to carry, in place of external fuel tanks, up to 3,700lbs of bombs!

 

[JonJGoldberg]

Reply to Sal Monella >>>

This has been fun, try your best to stop making this personal, my sphincter, and what I do with it is not open for discussion here, I believe there is a thread for off topic things, where you may be able to satisfy your newly found interest. Please note, as I have not posted anything there, all data has been extrapolated using the best available models.

More on topic, I feel we are getting to be repetitive… but I have a new angle for ya…

This time, in effort to beat the eraser, I'll start from where you started: Like most of us, it seems we must each edit data that is available. We all must extrapolate the data we find. I tried to point this out using the Cradle of Aviation article you asked I read. I posted the info given for the XP-47J to show that we all (yes including myself) are guilty of being able to slant, ever so slightly taint things 'our way' even when we know better. A better example (within Sal approved data) I can not, as of yet, find; how in the world (of sim reality beer) can an aircraft, whose best climb rate, taking what was printed at face value, be 4,900 ft/min @ SL 4,400 ft/min at 20,000 ft reach 20,000 in 4min 15 sec.? Want to know; Mother Nature has an opinion, guarding the '47, as it was her favorite plane of the time, she aided the craft with a well placed blast of her nostril… There fore defeating the best mathematician at there own game as she hates being quantified. So yeah, I decipher what I see, as you do. Take your beloved service manual, better yet, the service manual for a T-38 (I choose this aircraft as it is not a fighter; an aircraft whose service manual, I've seen, OK about 20 years ago, but I saw it, I figure represents both neutral ground, higher level of production). On the flight line, there was not a single pair of aircraft that exactly matched. When they left the factory, each was slightly different, they are built using jigs, by people. The sheet metal skins never had the rivet holes in exactly the same place. Replacement parts were/are in field tailored from their 'factory' stampings to exactly match their intended recipients. As a matter of fact, the factories normally produce these pieces (skin) ever so slightly different than original to allow 'fitting', or they are remanufactured in field using measurements from the donor for this reason. So with regard to the spec within your service books; it seems you expect my data to match yours exactly. It can't. Mine was taken from serial number 'x' and yours from 'y' it says so on the cover of my service manual. My plane is 158 lbs heavier than yours, at combat weight, climbs 180 ft /min slower, goes 11 mph faster. All these numbers seem just impossible to you, just 'plane' hogwash. You are entitled. As for me, the worst number here may be the climb rate; ((180/2900)*100) I'm off 6.2% from your bible, that, according to you, is just completely out of the ball park… your sending the clean up crew after the 'litter'. Mind you, I'd take a 6.2% improvement in my income, so this number is significant, to be sure, but it is hardly grounds for dismissal; we should be able to work on this together, as I'm willing to 'fix' my data; please just send me a copy of the original, or point me as to where to acquire it, I left E-mail address, you can see them in my profile. No more slander OK, the data is not WRONG, your data is not wrong. Climbing to 20,000 ft in 4min 15 sec, in an aircraft whose best climb rate is 4,900 ft/min, that's wrong.

For a closer look at how combat weight within my tables are determined: I started with 10997 lbs (funny, practically the same number, somebody please fill the tires), to which I added a 225 lb pilot, 75 lb radio, 30 lbs fudge factor (maybe the pilot naked is 225, maybe the radio weighs more, maybe there was 5 gallons of gas stuck from the last flight), 529 lbs of guns (M2=66.1 lbs), 1296 lbs of bullets (5.184 oz/round) @ 500 rpg 3336 lbs of fuel (6 lbs per gal/556 gal). This brings me to my 'combat weight figure'. I propose your Republic book I have one or more of the following happening, we have different pilots in mind, or a different amount of ammo.

As for the rest of my numbers, again they do not exactly match yours, we may argue about .3 sq foot of wing area, a ¼ inch in length; I feel as if this would not warrant a letter home to mama, you feel as if they disqualify my stats. OK.

But Sal, I have hope in you.

On Match Rules: We're going to race a semi, against a pick up truck at a drag strip. These two anonymous vehicles, although designed for clearly different purposes have in common the ability to tow a 14' power boat on its trailer, my intended 'job' for these vehicles, a sales man. I've told the salesman, who's paid by commission, to apply my deposit on the victor, as beside towing the boat, I want as much acceleration as I can get, that's what I want; of all the vehicles here, it's between these two. Now the semi is 10 times the price of the pick up, so the commissioned sales man says, hey Einstein (or bub), tell you what I'm goanna do, I'm goanna make this fair. The semi is currently equipped with 4 extra tires, 1 extra axel, a hitch that weighs a lot more than is required, it's got the capacity for all this extra gas. Now I promise that you will receive all of the features capacity of whichever truck wins, but I'm goanna take all this unnecessary stuff off, just for this race, so that you may more properly judge the results. Now it's clear that I would not accept these terms, further it's clear what the objectives are all around. I find the race as probable as our dogfight, we each see the other as the salesman. I'm not convinced that I'm in any way handicapping the semi, by requiring the salesman to keep the vehicles as they are, feel it wasn't be proper for the salesman to suggest loading the pickup with 4 semi tires, axel, and fuel tanks, as either which way, I'm screwed! …So much for your bomb analogy.

Happy Bird Day To All

 

[FLYBOYJ]

Take your beloved service manual, better yet, the service manual for a T-38 (I choose this aircraft as it is not a fighter; an aircraft whose service manual, I've seen, OK about 20 years ago, but I saw it, I figure represents both neutral ground, higher level of production). On the flight line, there was not a single pair of aircraft that exactly matched. When they left the factory, each was slightly different, they are built using jigs, by people. The sheet metal skins never had the rivet holes in exactly the same place. Replacement parts were/are in field tailored from their 'factory' stampings to exactly match their intended recipients. As a matter of fact, the factories normally produce these pieces (skin) ever so slightly different than original to allow 'fitting', or they are remanufactured in field using measurements from the donor for this reason.

Just to ping off JJs comments - although aircraft from WW2 to today's fighters are mainly built up in assembly jigs, once in the field they tend to "grow" in one direction or another. Its very hard to use a cannibalized skin from one aircraft to another because rivet holes will be slightly off. Any time skin repairs are accomplished, the preferred method is to manufacture a "blank" sheet line it up where it should be and "back-drill" the rivet holes using the existing structure as a template.

Anytime you start changing major structural components in the field because of damage, especially damage that placed large loads on the airframe, the aircraft will never be the same. Many times it will possess some abnormality ( flying crooked, requiring more trim in a certain configuration, not achieving the max speed as indicated in the flight manual). I've also seen "positive" results from major field repairs as well, but those are far and few....

JJ - I hope you don't mind me addressing you that way, being a former New Yorker, it only seems natural...