Re: Performance of the Fw 190A on the Deck?
 

There seems to be a typo but the relation itself just shows that at given Cl (or AoA) the weight and speed relation stays constant. That also means that the formula can't be used to determine speed change in the case where the Cl changes.

The way I calculate the speed change is very basic stuff. I assume that at any steady flying condition drag equals thrust ie:

D = T

Drag being:

D = Cd * p * V^2 * 0,5 * A

Where Cd is drag coefficient, p is density, V is speed and A is reference area (wing area).

And Cd being:

Cd = Cd0 + Cdi

ie total drag coefficient is zero lift coefficient plus induced drag coefficient the later being:

Cdi = Cl^2 / (pii * AR * e)

where Cl is lift coefficient, AR aspect ratio and e efficiency factor. The lift coefficient is:

Cl = L / (A * 0,5 * r * V^2)

where L is lift force (9,81 * weight in this case using SI).

And the thrust is:

T = (n*W) / V

Where n is efficiency and W is engine power.

I use spreadsheets for iterations, in the Typhoon example I used Cd0 value 0,019, wing area 25,83m2, AR 6,2, 80% prop efficiency, e value 0,8, density 1,225 kg/m3 and weights 4800kg and 5300kg.

Re: Performance of the Fw 190A on the Deck?
 

That is completely wrong, Not even close to the fundamentals of aerodynamics completely wrong.

Graham you have been away for a while. If we hold AoA constant and increase weight, speed MUST increase.

Lift has to increase to meet the amount required. If our weight goes up then our lift required also increases. Our lifting pressure has increased.

Remember our fixed relationship of Coefficients of Lift, Drag, and angle of attack. Holding angle of attack constant, we know the ratio is constant. The only way to increase the forces and maintain the same ratio of lifting pressure to dynamic pressure is raise the dynamic pressure to meet the higher lifting pressure.

Look, I can produce multiple references what I am saying. You guys have, "please believe me" and you compadre's....well, whatever the heck that is

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

Riding coat-tails right down the drain....LMAO.

Re: Performance of the Fw 190A on the Deck?
 

On the other hand you might like try being polite, even when you disagree with what others have said.

Re: Performance of the Fw 190A on the Deck?
 

Perhaps you should try to prove your point with calculation instead.

Re: Performance of the Fw 190A on the Deck?
 

[If we hold AoA constant and increase weight, speed MUST increase.

Lift has to increase to meet the amount required. Crumpp[/quote]

AoA is Angle of Attack, the angle an aircraft makes with the airflow, for anyone still with us who doesn't know the term.

Ah. I begin to understand. However, there is no need to hold AoA constant. Why should you want to? Yes, lift has to increase to allow for the extra weight. This is done by flying at a slightly higher AoA giving a slightly higher CL, and hence a higher drag. Higher drag = lower speed. QED. However, this increase in drag is insignificant, for the reasons explained.

If, for some reason, you wanted to fly at the same AoA (bearing in mind that no machines of the period had the instruments to do this) then yes, an increase in weight would have to be balanced by a higher q, or speed. But you are already flying at maximum power, so you can't do this.

This flying at constant AoA would, I think, be relevant to cruise, where a heavier aircraft does indeed require a higher speed. This is because the optimum cruise point is where the induced dag (which reduces with the square of the speed) equals the zero-lift drag (which increases with the square of the speed). An increase in weight needs an increase in lift, which creates an increase in induced drag. A new optimum, induced drag = zero lift drag, requires a higher zero-lift drag which is found at a higher speed. The resulting AoA will be close to, if not identical to, that of the previous weight.

Your equation may hold at cruise conditions, if AoA is held constant. It does not apply to flying at maximum power, where additional lift can only be found by increasing AoA.

Re: Performance of the Fw 190A on the Deck?
 

Quote:

This flying at constant AoA would, I think, be relevant to cruise, where a heavier aircraft does indeed require a higher speed.

Graham I think it certainly has been quite a while since you worked with aerodynamics. From what I understand, it is like riding a bike and it comes back.

You missed the point on the parametric study. The only way to judge the affects of weight is to hold a constant, adjust weight, and measure the results. Otherwise we miss the forest for the trees.

That is the basic scientific method and is generally accepted for aerodynamics and applied physics.

Not doing it leads to false conclusions on the relationships. We wind up with statements like the affect of weight is insignificant because we only see a small reduction in speed.

Here is another reference on this subject:

http://img393.imageshack.us/img393/7...cstudy3st6.jpg
http://img393.imageshack.us/img393/7...ebc87bbfb0.jpg

Now I understand you only wanted to make the point that "in regards to top level speed" in a very narrow definition, the affect of weight is insignificant.

I guess you could make that statement. I certainly would not make it. Once again it sounds to me like a Doctor claiming the small size of a cancer tumor means it is insignificant to the body.

Quote:

On the other hand you might like try being polite, even when you disagree with what others have said.

Hi Nick,

Point taken. And you are correct. Thanks.

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

Gentlemen:
I thought this thread was about whether or not the FW-190A was faster on the deck than any allied fighter? Well, why not ask those who were there? Forget trying to prove it by calculations as they completely ignore pilot ability and experience.

In my encounters, no FW-190 ever outran me on the deck or at 30,000 feet. Although I did not have the opportunity to dance with a FW-190D on the deck, I did a good jitter bug with at least 20 FW-190Ds and another 15 or so FW-190As at 30,000 feet. I was faster and could easily outturn them. On the deck, I had no problem staying with them. I chased one when my guns were jammed and was able to check his RPM at 2700 so I presume he was at full throttle. I had to keep retarding my throttle to prevent overrunning him. My P-51D indicated about 372mph at 100 feet. We changed the engine when it would not indicate more than 360/365 on the deck. We had one P-51D said to indicate 390 mph at zero altitude, but I have to wonder if there was a problem with the airspeed indicator, as none of the other pilots reported that speed.

I recall reading a report from an 8th AF pilot who stated that a FW-190 ran away from him on the deck but do not recall what model it was.

Surely there must be other P-51 or FW-190 pilots on this board who could add some actual experiences to this discussion and whose end results differ from mine?

Cordially, Art Fiedler

Re: Performance of the Fw 190A on the Deck?
 

Hi Art,

We had some Vets from the 9th AF in the museum a while back. I will get more details from Mark as he related their story to me.

Anyway, it went something like this:

In the last few days of the war their flight came across an FW-190A down low. Wanting to take a good peek at this lone aircraft, the flight moved up on the 190's rear unnoticed. As the lead P51 moved off to the side to get a better look, the German pilot realized he had 4 P51's on his tail.

In an obvious panic, he rolled, split-S, and dove away. They followed him. After leveling off at treetop height, black smoke poured from the 190 and he left the P51's behind.

Oskar Bösch also outturned and outran a P51 flight over the Ardennes in December 1944. He told me that the first Mustang overshot him as he banked hard right. He then entered a turn fight with that Mustang which went for several circles before gaining gun solution. When he looked back, he saw a several Mustangs in the same circle. That is when he broke hard, opened up his "Ribbennol", and dove for the trees. He counted 5 Mustangs in pursuit that eventually gave up the chase.

http://baileyprints.com/prints/war-wolf.html

Oskar credits the low level speed of the FW190 as the reason he survived the war. In his words, "In my Focke, I feared no fighter I could see."

Thank you Art for your service to mankind. It is the reason why we can openly discuss these events today.

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

Mr Feilder I have sent you a PM.

Re: Performance of the Fw 190A on the Deck?
 

Totally non-technical I'm afraid. But the chart by M. Degnan is a bit misleading in showing the P-47D of March 1944 when the chart gives the time frame as 1943. By the time of the P-47's tests there would also have been the P-51B in service in addition to the new generation of 605AS-powered 109s. And, since the B-17 is mentioned it would have been interesting to see its performance also.

Anyway, an interesting thread.

Re: Performance of the Fw 190A on the Deck?
 

In the polar analysis, the weight is adjusted and the answer to the question in hand is calculated directly adjusting the Cl accordingly to keep thrust and drag balance.

The polar analysis is the very basic method of performance analysis, it can be found from any good aerodynamics book. The formula you used is based on the polar analysis but limited to one given Cl (or AoA).

Using the same terms; with the polar analysis we can see the forest and the trees, with your formula we can see only the trees.

Re: Performance of the Fw 190A on the Deck?
 

I think at the time that was the only P-47 data available. The chart was constructed several years ago IIRC.

Good to see you George, BTW.

All the Best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

You are right, I haven't been an Aerodynamicist for twenty years. I had worked on performance aerodynamics for the previous nineteen. Like riding a bicycle, I believe you said? Some things you don't forget.

You want a more academic source. I offer you "Design for Air Combat", by Ray Whitford C.Eng MRAeS. Page 13, "Trailing vortex drag typically represents 75% of the total drag in maximum sustained manoeuvre flight.........only 5 to 10% in the low altitude high speed flight." Trailing vortex drag is his term for induced drag. This value is for modern combat jets: for WW2 fighters at about half the speed the induced drag proportion will be higher, about 10-20%.

You might also wish to consider his Fig 16, where the 1g and 4g flight envelopes for the F-5E can be seen to be very close together, at max speed at sea level. That's very little change for a 300% increase in weight. You can see why the change in level speed due to a 5% increase in weight is regarded as insignificant.

In combat, every little helps, of course. In this sense, insignificance can be claimed as the effect is less than the variation to other causes such as surface finish, fit of panels, age of engine, excrescence standard. And indeed, pilot handling. A mis-set trim will create more drag than a couple of mph. If the radiator shutters are set too open they will create more drag.

Re comments from actual pilots: They were referred to much earlier in the thread, at least indirectly. Every kill of a fleeing Jabo proved that other fighters could outrun an Fw 190, so the basic statement was untrue. Yet many Fw 190s did escape their pursuers, and the question how such differences arose led to discussions of basic aerodynamics.

Which I suspect has gone far enough now.

Re: Performance of the Fw 190A on the Deck?
 

Ah, this is where the things get complicated. Generally the polar of the aircraft stays pretty unchanged up to mach 0,4-0,5. And at low altitude WWII fighters reached this kind of speeds, 600km/h being slightly below mach 0,5 at sea level at standard atmosphere. So simple relations based on assumption of constant polar work pretty well for this kind of analysis.

However, around Mach 0,5 the polar shape as well as the zero lift drag coefficient start to change so the formulas intended for slow speeds and constant shape of the polar work poorly for the jets which can do around Mach 1 at sea level. In other words, induced drag proportion of the jet aircraft drag does not prove much here because these fly at speeds where the drag and lift relations are very different and not constant.

IMHO the best way to show the limitations of constant AoA analysis is to rewrite L/D ratio as:

L/D = Cl/Cd = Cl/(Cd+Cdi)

In other words there is basic polar analysis hiding behind, the Cl and Cdi are just assumed to be constant. And that is a wrong assumption for this particular case.

Re: Performance of the Fw 190A on the Deck?
 

Art and Crumpp:

Thank you for the observations based on actual experience.

I found it interesting that your threads gave quite different perspectives on the ability (or otherwise) of the Fw 190A to outrun Allied fighters on the deck.

Variations in the performance of individual aircraft of the same type and possible reasons for such variations were themes earlier in the discussion. This made me recall (another!) quote from The JG 26 War Diary Vol Two: '...was chased and caught by Lt. Paul Jasper, whose P 47D-16 was 15-20 mph faster than any other aircraft in his squadron owing to his crew chief's initiative in sanding, waxing and polishing it.'

Clearly, it is impossible to assess the reliabity of the cause and effect relationship set out in this statement. What is striking, however, is the statement that one aircraft was significantly faster than the others in the squadron. This is entirely consistent with the idea that there were considerable variations between the performances of aircraft of the same type.

Regards

Don W

Re: Performance of the Fw 190A on the Deck?
 

A Ta152H certainly could outrun a P-51D at low level for Tank did. The drag on the Ta must be greater than on a 190.

Re: Performance of the Fw 190A on the Deck?
 

So is the power. The encounter supposedly took place at altitude, not as far as I know specified, where the different behaviour of the various superchargers could be very relevant.

However, few have argued that a Ta 152 was slower than Allied fighters.

Re: Performance of the Fw 190A on the Deck?
 

You are most welcome Boomerang. I personally am most thankful to Col Feidler for joining us too.

Quote:

Clearly, it is impossible to assess the reliabity of the cause and effect relationship set out in this statement. What is striking, however, is the statement that one aircraft was significantly faster than the others in the squadron. This is entirely consistent with the idea that there were considerable variations between the performances of aircraft of the same type.

Absolutely.

It's funny too the bond that forms between a pilot and his aircraft. Even my little GA family mover has an emotional attachment.

I mentioned to my wife last flight that I was thinking about getting a Mooney. It's faster and more economical than what we have now. The wife wouldn't have a thing to do with that idea. Completely out of character for her, she snapped at me to quit being disloyal to "Bravo Fox" as the plane had always carried us safely through every encounter. I though it was funny as she is not a pilot. Women huh? God bless em.



Of course, I will admit that the last thing I do before shutting out the lights in the hanger is get pat her on the cowl and thank her for being such a good airplane.

Oskar told me he was extremely upset when he lost one particular FW190 after being shot down. He was really upset when they hauled the plane off to the scrap yard an still remembers little details about that one aircraft. It was definitely his favorite.

Quote:

You might also wish to consider his Fig 16, where the 1g and 4g flight envelopes for the F-5E can be seen to be very close together, at max speed at sea level. That's very little change for a 300% increase in weight. You can see why the change in level speed due to a 5% increase in weight is regarded as insignificant.

I think we are still just looking at maximum speed and nothing has changed in my opinion:

Quote:

Crumpp says:

From Perkins and Hage, "Airplane Performance Stability and Control"

http://img396.imageshack.us/img396/1...affectsmm2.jpg
http://img396.imageshack.us/img396/1...97ac276c8e.jpg

http://img512.imageshack.us/img512/5...ffects2wm7.jpg
http://img512.imageshack.us/img512/5...25c2540443.jpg

http://img382.imageshack.us/img382/5...ffects3mf0.jpg
http://img382.imageshack.us/img382/5...f825ffdcbb.jpg

Additionally it is very hard to compare aircraft like the F-16 to WWII designs. The entire design emphasis has evolved over time as to what is important in the fight due to the abundance of thrust available.

From Andrew M Skow paper "Agility as a Design contributor" AIAA library:

http://img396.imageshack.us/img396/8...yandconhz2.jpg
http://img396.imageshack.us/img396/8...7ddddcde8d.jpg

Mr Skow's paper is a worthwhile read and I meant to share it but unfortunately it exceeds the boards allotted attachment size for pdf files.


All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

Obviously, I enjoy a bunch of equations as much as anybody but then I glanced up, saw the title of this thread and got distracted...

Something else I picked up from AIR40/152 was some numbers for the Fw 190 F-9. I've posted it as an attachment to preserve the layout, superscripted letters etc.

I get the words and the gist but if anyone can explain some of the other terms used, I'd be interested.

Re: Performance of the Fw 190A on the Deck?
 

That looks like Vmax for Kampfleistung, Notleistung, and Dauerleistung speeds for the FW-190F9 in the 1st and 2nd Gear supercharger for the aircraft with and without a load both indicated and true.

The time to climb, climb rate, and service ceiling at 4100kg is included as well.

That is from the Kennblatt and is used for flight planning purposes.

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

Use the 51D versus the 51B-15 with the same 1650-7 engine. The weight increase was about 6%, the aerodynamics for Parasite Drag and Induced drag are the same for both airframes.

The 51B with same fuel load was about 600+ pounds lighter - mostly due to the extra pair of 50 cal plus 880 rounds extra ammo.

under these TO conditions the P-51B-15 was about SQRT (Wp51d/Wp51b) difference ~ 1.03 faster than the D... on the deck and at 25,000 feet and everywhere in between.

10+ mph is not insignificant - important enough for NAA to redesign the P-51B/D to the P-51H

Re: Performance of the Fw 190A on the Deck?
 

[quote=Graham Boak;70211]Graham, what you say about low speed/low altitude versus high speed/low altitude is true relative to discussions about relative induced drag and parasite drag

But whether the extra weigh is due to increased fuel, or internal load, or more structural weight for same basic airframe, the Velocity change for same power settings and the increased AoA resulting in a higher CL results in the SQRT (Wheavy/Wlight) change in V

Re: Performance of the Fw 190A on the Deck?
 

Bill, it is obvious that P-51B/C was aerodynamically slightly different than D/K. I cannot say for sure, but I suppose there might have been some other slight differrencies, eg. in props. That said, drop of maximum speed was the result of several minor changes, and not only one factor. Still, 10 mph is within marigin for error and may purely depend on quality of factory fresh aircraft, not to mention worn out airframes.
Overall, the point that Graham tries to make is not that the weight is unimportant. He just merely points out, that differencies of weight caused by fuel consumption are mariginal for aircraft performance in horizontal flight. It does matter in vertical manouvers, though. This is obvious for anyone, who ever attempted to calculate such things, just as it is obvious, that adding a few pounds of putty and lacquer will increase the horizontal speed!

Re: Performance of the Fw 190A on the Deck?
 

For 600lbs increase from 9680lbs to 10280lbs in the case of the P-51B causes 1,48km/h speed reduction for max speed at sea level. The parameters being 352mph at sealevel and, 1580hp (67") and 120kp exhaust thrust, prop efficiency 80% and value of the e being 0,8. Calculated Cd0 being 0,02054.

Re: Performance of the Fw 190A on the Deck?
 

The power is constant, however, the propeller thrust increases when the speed decreases and therefore the speed reduction can't be calculated directly but using the iteration to reach new balance between the drag and the thrust.

Re: Performance of the Fw 190A on the Deck?
 

You didn't understand what he said.

Re: Performance of the Fw 190A on the Deck?
 

I did; because the drag must equal thrust:

D=T

Then at constant power the thrust increase when the speed decrease because:

T = (n*W) / V

Where n is efficiency and W is engine power. Therefore the iteration process is needed to find the new balance between the drag and the thrust.

Re: Performance of the Fw 190A on the Deck?
 

Franek - Respectfully, I made a living for several years "calculating such things" following a Masters Degree in Aero. Having said this, my real expertise was Structures, Aeroelasticity and finite element modelling.

It is not so obvious to me that Weight delta does not affect top speed - because it does. You may not agree my math or logic, but respectfully, bring your own if you have a different POV.

Marginal seems to be what you are debating and I'm ok with you and Graham dismissing the value to Max speed available to say a P-51B after getting rid of its Fuselage tank 85 gallons. The math says it's about 10-12 mph.

If that is insignificant to you we can agree your terminology, but the delta is not due to plugging gun ports, or polishing the airframe, or switching engines...

Hari - two things about your comments.

First- at Vmax the Thrust Hp is maximum for that altitude and weight.

When weight increases, for the same airframe, the Thrust Hp remains the same, but Vmax decreases alightly as the AoA must increase to maintain level flight for that Thp and weight condition.

In other words the Thrust available is the same for both weight conditions, but the velocity Attainable is Less for the heavier weight conditions.

In other words, Thrust HP may not increase beyond the max Thrust Hp available in level flight.

If you want to demonstrate the math that proves a slight increase in AoA from freestream impingement on the propeller plane increases the change in momentum of the mass flow through that plane (positively) - give it your best shot.

By your anology , as the ship climbs at a steeper angle relative to freestream, the thrust would increase?

By using the Propeller/Engine thrust equation as you used it (which is appropriate for level flight) then as the angle of Attack increases you would quicly reach a point where sustainable velocity is much lower than it was in level flight... and your thrust increases dramatically above it's max rated Hp Thrust in level flight. Do you believe this?

Re: Performance of the Fw 190A on the Deck?
 

Your specific references for each claim you just made for the P-51B?

For example "e" is derived empirically, because the effect of spanwise lift distribution, increase in trim drag and the increases in all forms of drag on the airframe. .8 is a good rule of thumb for conservative preliminary design purposes - but only that unless you have test results?

Ditto prop efficiency. .8 to .85 are good Prelim Design numers. So where would point me to .8 as being correct for the P-51B?..

Cd0 = .02054? and your source is? That is higher than the Ames wind tunnel model with real airframe.

Having said that, how do you arrive at approximately 1mph delta for a 6% weight increase? What math are you using?

Re: Performance of the Fw 190A on the Deck?
 

Forgot to answer this in detail. The external differences were to remove turtledeck, change the slope of the windscreen, add the bubble canopy, increase the Root chord to five a steeper angle of the inboard wing to fuselage.

Internal differences, Uplocks for wheels, increased thickness of ammo doors and add 2x .50's plus 660 rounds of ammo, and beef up the vertical stabilzer spar/fuse attach structure..slight change in horizontal stabilizer incidence

Props same except K had a slightly different prop, only to extent of removing sleeve at propeller hub. Same wing except as noted above

Later the D got metal elevators, tail strake.

Net - 51D cleaner, heavier, slower than P-51B-15 with same prop and engine in both airframes - about 10-12 mph on a statistical average via flight tests at Wright Pat and Eglin and NAA facilities.

Re: Performance of the Fw 190A on the Deck?
 

I don't actually calculate the thrust hp but directly the thrust from the brake hp; the hp chart I used just gives the bhp.

The thrust remains same at original velocity but at the new balance point at lower speed the thrust will be higher.

Ok, I'll demonstrate using the calculation I did for the P-51B:

First thrust at original 9680lbs (4390,85kg) and 352mph (566,368km/h=157,3244 m/s):

1580hp = 1178014 W
exhaust thrust = 120kp = 1176,798N
Propeller Thrust = (0,8*W)/V = 5991,216N
Combined thrust = 7168,014 N

Then thrust at 10280lbs (4663,008kg) and 351mph (564,887km/h=156,913m/s)

1580hp = 1178014 W
exhaust thrust = 120kp = 1176,798N
Propeller Thrust = (0,8*W)/V = 6006,923N
Combined thrust = 7183,721N

Now we know that at the supposed new balance point there is 15,7N more thrust available so lets check if the D = T at these points:

First at 9680lbs

Speed =157,324m/s
density = 1,225kg/m3
wing area = 21,83m2
Aspect ratio = 5,83
Lift = 4390,85*9,81 = 43059,51 N
Calculated Cd0 = 0,020504
e = 0,8

Cl = L / (A * 0,5 * r * V^2) = 0,130111
Cdi = Cl^2 / (pii * AR * e) = 0,001156
Cd = Cd0 + Cdi = 0,021659

D = Cd * r * V^2 * 0,5 * A = 7168,014N = T Check!

Then at 10280lbs

Speed =156,913m/s
density = 1,225kg/m3
wing area = 21,83m2
Aspect ratio = 5,83
Lift = 4663,008*9,81 = 45728,487 N
Calculated Cd0 = 0,020504
e = 0,8

Cl = L / (A * 0,5 * r * V^2) = 0,1389007
Cdi = Cl^2 / (pii * AR * e) = 0,0013171
Cd = Cd0 + Cdi = 0,0218206

D = Cd * r * V^2 * 0,5 * A = 7183,721N = T Check!

Q.E.D.

It's calculated backwards from the linked chart:

http://www.wwiiaircraftperformance.o...level-blue.jpg

And using something else does not make a big difference, ballpark should be correct. The point here is to show the principles.

It's just an estimate. I can calculate e from various data but 0,8 should be a good enough estimate.

Same here, just an estimate. I have the Hamilton standard red book so I can make a better estimate but again 80% should be good enough for the purpose.

I have listed the formulas on the page 5 of this thread and Chapter 14 of Hoerner's "Fluid Dynamic Drag" shows an example.

Basicly we don't know the Cl, drag, thrust nor speed at new balance point. However, we know how each of these behaves so we can solve the problem with iteration process. If you look the above calculation, you can see that it really works.

I can put together a small spreadsheet to demonstrate the calculation if you are interested; you can change the parameters and see the results instantly. My stuff is written in Finnish so translating might take some time.

Re: Performance of the Fw 190A on the Deck?
 

Bill
There must have been some differrencies in aerodynamics, because P-51D turned highly unstable at high speeds and had to be modified. That is one thing.
Another is accuracy of such calculations. As we know, engineering theories are based on approximates and simplified theories, and quite often we do not know what is actually going on. This is very important in understanding calculations of performance.
If methods widely used give us 10% accuracy (~40 mph!), and the result must be verified in tests of actual aircraft, which then has some not insignificant margin for quality of production, then we find that those few miles are just unmeasurable. On the other hand, we know that horizontal speed is just resulting from several factors. The most important is the airfoil used, then wing, then airframe, then engine and prop. Given each factor's share, it was concluded that small changes of weight are just unimportant in overall picture. That is what Graham is trying to show all the time.
BTW
Spitfire IX and Mustang III/IV/IVA were powered by the same Merlin engine. Which one was heavier and which one was faster?

Re: Performance of the Fw 190A on the Deck?
 

http://img115.imageshack.us/img115/9...sepowerfk2.jpg
http://img115.imageshack.us/img115/9...19c385d51d.jpg


Actually you do calculate THP. You just don't seem to understand completely exactly what you are parroting.

All the best

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

The designs had different stability and control issues. Bill is correct in his assessment however.

http://img148.imageshack.us/img148/2...ndddraggf2.jpg
http://img148.imageshack.us/img148/2...a31e47b1fd.jpg

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

OK, so what is the point in underlining some of those figures? How about wetted area and the method it was calculated in each case? How about different AoAs or Res? Could you explain to us what is scientific value of the table while discussing aerodynamical characteristics of P-51?

Re: Performance of the Fw 190A on the Deck?
 

Quote:

OK, so what is the point in underlining some of those figures?

To make it easier for you to find the values measured by different agencies and test facilities that where equal. It was just a courtesy, Franek. It was not meant to offend you.

You are welcome to the entire report. It was given at an AIAA conference and is a very interesting read exclusively on the P51 series.

PM me if you would like a copy and it details the methods of measurement.

All the best,

Crumpp

Re: Performance of the Fw 190A on the Deck?
 

If you care to read the part you quoted, the power unit BHP is allready converted to the Watts (SI unit) at that stage and then directly calculated to the corresponding amount of thrust, Newtons in SI units.

And as a friendly advice (again); Please leave that agressive attitude to the another forums.

Re: Performance of the Fw 190A on the Deck?
 

Which makes no difference whatsoever. You are still using Thrust Horsepower. There is nothing aggressive in the facts.

Re: Performance of the Fw 190A on the Deck?
 

If you want to see the thrust horsepower in the calculation, just convert the power value back to bhp and multiply with n. However, I don't see any point to do that because, after initial conversions, the entire calculation is done with SI units.

And continous use of harsh words and continous claims that I don't understand what I'm doing, are indeed agressive actions.