Spit 5

[Crumpp]

38 mph gain (based on speculation) for 750hp input.  

9 mph gain (based on verifiable data) for 750 hp input with NO WEIGHT GAIN.

Thrust is opposed by drag right??

Crumpp

[gripen]

Originally posted by Crumpp
Your right I meant Merlin 61 (+15), typo.  So It increased
 60Km = 37 miles per hour to 70 km = 43mph for a 500 hp increase and recieved an additional 40 km = 24mph for adding another 150hp.

Total gain; 750 hp = 61mph - 67mph

Nonsense, you apparently can't calculate nor understand what we are talking about. The output at 3k increased roughly following amount:

Merlin 61 (+15) about 1550 hp
Merlin 66 (+18) about 1700 hp => 150 hp gain over Merlin 61 and 40 km/h increase in speed.
Merlin 66 (+25) 2050 hp => 500 hp gain over Merlin 61 and 60-70 km/h increase in speed.

BTW you might be suprised to know that 500 + 150 = 650 but I wonder why you are making such calculation?

Originally posted by Crumpp
The Spitfire added a huge amount of additional power for tiny gains in speed. Why? It had to fight to overcome the great lift it's wing provided.

Nonsense, you apparently still can't understand the induced drag despite all the sources. At any given speed the Fw 190 had more drag due to lift than the Spitfire. The numbers are clear.

Originally posted by Crumpp
Now lets look at verifiable facts on the Spitfire:

No need to comment, you are comparing planes at different altitudes,  FTHs and ratings without sense. BTW JL 165 performed below average as Nashwan noted, see this.

Originally posted by Crumpp
So for 750 hp gain (which you claim) we see a top speed increase from the Merlin 61 to the Merlin 66 (+25) OF:

Merlin 61 - 403 mph
Merlin 66 -  441 mph (based on speculation since we have no speed test or hard data at these conditions)
Merlin 66(+25) - 389mph (the one we do have hard data on.  It did gain 9 mph over the Merlin 61 at the same height.)


38 mph gain for 750hp input.

This part is so laughable that I had to quote it anyway. Shortly total nonsense.

Originally posted by Crumpp
Which BTW your numbers in now way match the calculator from the US Naval Academy Post Graduate.
I would apreciate it if you would list all the values you are using.

E factor etc...

All the needed values are listed allready above including E (efficiency) factor. As noted above, I used same E factor 0,9 for both planes. But as NASA site notes, the Spitfire had near ideal shape of the wing, so here are the values at 3g load using E factor 0,95 for the Spitfire and 0,8 for the Fw 190:

Spitfire IX
300km/h Cl=1,043 Cdi=0,0650
600km/h Cl=0,261 Cdi=0,0041

Fw 190A-5
300km/h Cl=1,451 Cdi=0,139
600km/h Cl=0,363 Cdi=0,00869

BTW the calculator in your linkdoes not calculate Cdi nor Cl at given load, use formulas from NASA links above. Remember your own words:

"You cannot argue though with the science. The numbers don't lie."

gripen

[Crumpp]

http://www.fourthfightergroup.com/eagles/spit9.html

http://www.fourthfightergroup.com/eagles/jl165.html

http://www.fourthfightergroup.com/eagles/jl165.html

Please find were the spitfire received the huge speed benefits for the HUGE amounts of Horsepower gains it made with out a weight gain?

http://www.grc.nasa.gov/WWW/K-12/airplane/forces.html

Since Drag is the force which opposes thrust.  The Spitfire, being of so little drag as you claim, should make some big gains for a small amount of Horsepower.  It should flat out leave the 190 in the dust.  Please show it with verifiable data because at full throttle height (the different altitudes you claim I was trying to manipulate the data) the gains are rather tiny.

The derivation of the equation for the induced drag is fairly tedious and relies on some theoretical ideas which are beyond the scope of the Beginner's Guide. The induced drag coefficient Cdi is equal to the square of the lift coefficient Cl divided by the quantity: pi (3.14159) times the aspect ratio AR times an efficiency factor e.

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

What are the values you are using for "e"?
How are you figuring Cl - The link I provided figured Cl out for you.

Since you have already messed up the AR several times, who is to say but YOU if you have the other values correct?  Your calculator manipulation is but smoke and mirrors.

This equation gives us a way to determine a value for the drag coefficient. In a controlled environment (wind tunnel) we can set the velocity, density, and area and measure the drag produced. Through division we arrive at a value for the drag coefficient. As pointed out on the drag equation slide, the choice of reference area (wing area, frontal area, surface area...) will affect the actual numerical value of the drag coefficient that is calculated. When reporting drag coefficient values, it is important to specify the reference area that is used to determine the coefficient. We can predict the drag that will be produced under a different set of velocity, density (altitude), and area conditions using the drag equation.

http://www.grc.nasa.gov/WWW/K-12/airplane/dragco.html

Your string of numbers in reality means nothing without the stated parameters.  If you were the aeronautical genius slide rule cowboy you claim to be you would have known that and posted the parameters and values.

So lets get back to basics and please show me the huge speed increase's the Spitfire IX received for the amount of horsepower dumped into it.  Even some pilot anecdotes of Spit IX's fighting in the vertical against 190's would help your case out.

I tend to believe Science and History over smoke and mirrors.  Capt. Brown had it right when he said the FW-190 and Spitfire where like "Blondes vs. Brunettes" neither one was better than the other.  They are about as evenly matched as tow fighters can be.  The Spitfire Merlin 66 (+25) is the correct opponent for the FW-190A8.  Otherwise the FW-190A will have a larger advantage than it should have in 1944.

Crumpp

[gripen]

Originally posted by Crumpp

http://www.fourthfightergroup.com/eagles/jl165.html

Please find were the spitfire received the huge speed benefits for the HUGE amounts of Horsepower gains it made with out a weight gain?

Here Crumpp purposedly selects the worst available data set for the Spitfire as noted twice above.

Originally posted by Crumpp
Since Drag is the force which opposes thrust.  The Spitfire, being of so little drag as you claim, should make some big gains for a small amount of Horsepower.  It should flat out leave the 190 in the dust.

Here Crumpp purposedly mixes up induced drag and total drag. I have pointed out above that the Spitfire had lower induced drag than the Fw 190 at any given speed and g load, and there was no large differences in the total drag. At same output both planes were about as fast, even Crumpp's own data supports this.

Originally posted by Crumpp
Please show it with verifiable data because at full throttle height (the different altitudes you claim I was trying to manipulate the data) the gains are rather tiny.

Above I have showed twice the speed gains at the MS gear FTH (about 3k) of the Merlin 66 (+25), that's the only altitude where the 2050 hp output is relevant. As for comparison Crumpp came up with nonsense comparison by summing up the hp increase of the +18 and +25 Merlin 66 at 3k and using this for comparison at the FS gear FTH of different rated engines.

Originally posted by Crumpp
The derivation of the equation for the induced drag is fairly tedious and relies on some theoretical ideas which are beyond the scope of the Beginner's Guide.

Actually the calculation is very easy by using the formulas from the NASA site (links are above). It's not my problem if this is beyond Crumpp's capabilities.

Originally posted by Crumpp
The induced drag coefficient Cdi is equal to the square of the lift coefficient Cl divided by the quantity: pi (3.14159) times the aspect ratio AR times an efficiency factor e.

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

What are the values you are using for "e"?

The values for "e" are mentioned twice above.

Originally posted by Crumpp
How are you figuring Cl

The NASA site gives needed formula, the link is above.

Originally posted by Crumpp
The link I provided figured Cl out for you.

Crumpp's link gives Cl just at the given angle of attack. The formula in the NASA site gives Cl at any given speed, altitude and g load combination for any given wing area and weight combination.

Originally posted by Crumpp
Since you have already messed up the AR several times, who is to say but YOU if you have the other values correct?  Your calculator manipulation is but smoke and mirrors.

I have listed all the needed values above. Crumpp is free to do his own calculations if he can.

Originally posted by Crumpp
Your string of numbers in reality means nothing without the stated parameters.  If you were the aeronautical genius slide rule cowboy you claim to be you would have known that and posted the parameters and values.

I have listed all the needed parameters above. It's not my problem if Crumpp can't use them.

Originally posted by Crumpp
I tend to believe Science and History over smoke and mirrors.

Well, we have seen above Crumpp creating his own version of Science and History.

gripen

[Crumpp]

Quite avoiding the issue and simply point out the huge speed gains the Spitfire recieved for the large amount of horsepower dumped into it with no weight gain.


Crumpp

[VO101_Isegrim]

Originally posted by gripen
Here Crumpp purposedly selects the worst available data set for the Spitfire as noted twice above.

gripen

Actually Crummp only choosed the very best data available for a serially produced Spitfire LF IX. All the rest IXLF data on that site refer to prototypes and experimental planes with propellers that were never put onto mass produced Spitfires, or injection pumps that were toyed with on single prototype airplane.

Like it or not, the JL 165 test report is the ONLY performance data referring to a serial production Mk IX LF on the highly biased 4th FG site. There`s simply no other to choose from.

[gripen]

Dear Isegrim,
There is data on the Spitfire VIII  JF 275. The main aerodynamic difference if compared to the Spitfire IX is  taillwheel. Besides even you self have admited in past that  the JL 165 performed below average and  the mentioned site is not the only source of the available data.

gripen

[Crumpp]

Quite avoiding the issue and simply point out the huge speed gains the Spitfire recieved for the large amount of horsepower dumped into it with no weight gain.


Crumpp

[Crumpp]

Actually the calculation is very easy by using the formulas from the NASA site (links are above). It's not my problem if this is beyond Crumpp's capabilities.

Really?  NASA says the Cl is rather complicated and is usually solved for experimentally in a wind tunnel.  That's why I provided a program that calculated it for you.  It changes with velocity, density, and angle of attack.

It's the FIRST sentence, right underneath the formula.

http://www.grc.nasa.gov/WWW/K-12/airplane/liftco.html

You need it to solve for the induced drag WHICH you claim to have done.

http://www.grc.nasa.gov/WWW/K-12/airplane/induced.html

Please tell us and scientific community how you have been calculating Cl  at the house.  I am sure there is prize money it somewhere for you!

The values for "e" are mentioned twice above.

No the value for "e" is the efficiency factor and you do not mention what you are using.  The shape of the airfoil determines it.

 

Here Crumpp purposedly mixes up induced drag and total drag.

No I have not confused induced drag and total drag.  I simply state that the Spitfire had more BASIC drag and ANY induced drag just adds to it.  You have confused my explanation of this with an advancement of a theory and induced drag was the lynchpin.

Sounds to me like you are trying to make a case that the Spitfires wing generated NO induced drag.  The combination of the two is the reason the Spitfire is not an energy fighter but rather an angle fighter.  That's why Merlin powered spits didn't follow 190's in the vertical.  

[

Above I have showed twice the speed gains at the MS gear FTH (about 3k) of the Merlin 66 (+25), that's the only altitude where the 2050 hp output is relevant. As for comparison Crumpp came up with nonsense comparison by summing up the hp increase of the +18 and +25 Merlin 66 at 3k and using this for comparison at the FS gear FTH of different rated engines.

No you have shown obvious data manipulation.  Fortunately the speed values are already determined and all anyone has to do is simply look for them.  What is NOT apparent or readily shown on that website is the huge amount Horsepower dumped into the Spitfire with very little speed increase and no weight gain.  The reader has to dig a little harder to see that and realize the penalty the Spitfire pays for it's wonderful high lift wing characteristics.

Please Gripen, before you make yourself look like even more of a butthead:

Quite avoiding the issue and simply point out the huge speed gains the Spitfire received for the large amount of horsepower dumped into it with no weight gain.


Crumpp

[Nashwan]

Quite avoiding the issue and simply point out the huge speed gains the Spitfire recieved for the large amount of horsepower dumped into it with no weight gain.

The test on JL 165 makes it quite clear the speed gains to be expected:

..4.41. An increase of about 950 ft/min in rate of climb and about 30 mph in all-out level speed is achieved by the increase of boost from +18 lb/sq.in. to +25 lb/sq.in.

If you look at the speed graph for JL 165, you'll see that in each gear, the speed increase from 18 lbs to 25 lbs was about 30 mph.

You can also look at the data for JF 275 http://www.fourthfightergroup.com/eagles/spit8.html

As you can see, speed increase was about 25 - 30 mph at altitudes where 25 lbs boost could be used.

[VO101_Isegrim]

Originally posted by gripen
Dear Isegrim,
There is data on the Spitfire VIII  JF 275. The main aerodynamic difference if compared to the Spitfire IX is  taillwheel. Besides even you self have admited in past that  the JL 165 performed below average and  the mentioned site is not the only source of the available data.

gripen

What are the conditions of  JF 275? Only the data is posted on the site, nothing about the condtions.

However, a complete report is known for the Mk VIII JF. 934F. It shows 391 mph obtained at FTH. Compares very well to the JL 165`s 389 mph, and it`s quite reasonable relative to the Mk VIII performance. Considering such speeds were obtained with no less than 1700 HP available, it tells quite a bit about the Spit`s aerodynamic "effiency".

Even though I`d willing to accept there may be better performing serially produced Mk IXs and Mk VIIIs (other than Mike`s favourite prototypes for the show), the fact is there`s no single report with known conditions that would show higher performance than 389mph for the serial Mk IX, and 391mph for the Mk VIII.  Any FW 190A is faster than that by a large margin, ie. the A-5s max. level speed being 415mph in multiple measured tests. It would be faster even with the optimum ca. 400mph figures used for the Mk IXLF, too.

[Nashwan]

. wip

[MiloMorai]

JF275 came off the production line Nov 21 1942. It was one of 70 Spitfires (VII, VIII, IX, XI, XII) on test in May and June 1943. JF275 was 6-7 months old at the time. It had had 2 engines changes, Merlin 61 > 66 > 61.

Tests done with the new tropical filter in JF275 had a FTH (26800') speed of 397mph and with a backing plate installed 402mph at FTH (27700'). pg 281 Spitfire: The History

The Fw190A-8 could only manage 375mph at 26800' and 365mph at 27700'. The Spitfire VIII JF275 with a Merlin 61 was 22mph and 37mph faster and that is with a tropical filter fitted.

[VO101_Isegrim]

So in other words, JF 275 was just another experimental plane (as Milo pointed out). Kinda expected that, Mike usually holds back information on the planes if he wants to sell them with good performance - see 25lbs MkXIVs that never were.

On the other hand, I don`t really see what the `44 A-8 has to do with it, it was in the A-5s timeframe. 190As never had impressive altitude performance, everybody knows that, the point being they were quite a bit faster at the normal combat altitudes than LF Spitfires up to around 7000m.

[MiloMorai]

Originally posted by VO101_Isegrim
So in other words, JF 275 was just another experimental plane (as Milo pointed out).

Only in your mind Barbi was it an experimental a/c. It was a production a/c that was used for testing.

Originally posted by VO101_Isegrim
Kinda expected that, Mike usually holds back information on the planes if he wants to sell them with good performance

And you don't?

Originally posted by VO101_Isegrim
Any FW 190A is faster than that by a large margin

Now the excuses come when he was shown he was wrong..

According to Crumpp, the A-8 had better performer than the A-5.