F4U in Europe (3 Viewers)

[Clayton Magnet]

But it was not the only one captured and tested

Interesting, thank you for the additional clarification.
My suggestion about the Faber 109A-3 was based on the fact that it was the only fighter varient Fw 190 to be captured and evaluated by the western allies, the rest being configured as fighter-bombers. Or so Wikipedia would have me believe.
Are you aware if the NAFDU ever tested the Faber aircraft against FAA Hellcats or Corsairs?

 

[NevadaK]

Here is a question for this thread. A number of aircraft comparative tests have been cited and a common response is that the "losing" aircraft wasn't being flown in its best configuration or performance.

My question is: What is the expected variance in performance from specifications for aircraft in use in the field?

For instance, if we have five F4U would we see a 5% variation in top speed and climb? Would there be variations in roll rates? Thinking about the different flight test comparisons, would this translate to an expected variation in the tested aircraft? The FW-190 test is a good example where a common comment is that the FW-190 was underperforming, but would this variance actually fall within what would be expected in the field.

 

[FLYBOYJ]

Here is a question for this thread. A number of aircraft comparative tests have been cited and a common response is that the "losing" aircraft wasn't being flown in its best configuration or performance.

My question is: What is the expected variance in performance from specifications for aircraft in use in the field?

For instance, if we have five F4U would we see a 5% variation in top speed and climb? Would there be variations in roll rates? Thinking about the different flight test comparisons, would this translate to an expected variation in the tested aircraft? The FW-190 test is a good example where a common comment is that the FW-190 was underperforming, but would this variance actually fall within what would be expected in the field.

IIRC from the factory a 3% performance variance was the requirement, I'm not 100% sure about this. (US manufacturers)

 

[Shortround6]

Here is a question for this thread. A number of aircraft comparative tests have been cited and a common response is that the "losing" aircraft wasn't being flown in its best configuration or performance.

My question is: What is the expected variance in performance from specifications for aircraft in use in the field?

For instance, if we have five F4U would we see a 5% variation in top speed and climb? Would there be variations in roll rates? Thinking about the different flight test comparisons, would this translate to an expected variation in the tested aircraft? The FW-190 test is a good example where a common comment is that the FW-190 was underperforming, but would this variance actually fall within what would be expected in the field.

I believe (and contracts could be different) around 3% was the usual tolerance. If the plane doesn't meet that figure on an acceptance flight it needs to be reworked and test again.
Sometimes there were penalties, plane would be accepted but so much for every MPH or KPH off the specified speed.

 

[NevadaK]

Thank you, Shortround6 and FlyboyJ.

If 3% from the manufacturer would you expect this variance to increase after some time spent in the field, or do you think this could be maintained throughout the aircrafts expected life?

 

[FLYBOYJ]

Thank you, Shortround6 and FlyboyJ.

If 3% from the manufacturer would you expect this variance to increase after some time spent in the field, or do you think this could be maintained throughout the aircrafts expected life?

I think so but a few things to consider...

Aircraft are not hand built (as some may believe). Major sub assemblies are built in jigs and fixtures and sometimes there may be multiple jigs and fixtures to support production demands. As long as the tooling is maintained and there is little to no difference between individual jig units, I believe this tolerance can (actually was) maintained.

 

[Shortround6]

It some case the planes were noted in test results as having poor or worn finish. And if this was at a test center than planes in the field could be all over the place.

The ground crew would do what they could depending on weather and supplies and sortie rate (flying every day isn't easy to keep up a good finish when you are trying to take of mechanicals.) If the Crew has a day or two off when the mechanicals are good and the weather at the field isn't too bad (even though not for good flying) then some paint work or fill work or a little hammering out of the dents may be done.

 

[pbehn]

Here is a question for this thread. A number of aircraft comparative tests have been cited and a common response is that the "losing" aircraft wasn't being flown in its best configuration or performance.

My question is: What is the expected variance in performance from specifications for aircraft in use in the field?

For instance, if we have five F4U would we see a 5% variation in top speed and climb? Would there be variations in roll rates? Thinking about the different flight test comparisons, would this translate to an expected variation in the tested aircraft? The FW-190 test is a good example where a common comment is that the FW-190 was underperforming, but would this variance actually fall within what would be expected in the field.

Roll rate is difficult to test. The biggest cause of variance in roll rate on planes of the same type is the size, build and strength of the pilots themselves, especially on planes like the Bf109, the cockpit is so cramped a big guy cant exert the same leverage as a small but stocky guy.

 

[emu27]

Range increases to 1500 nautical miles max with just one 150 external fuel tank. They could carry two of this

Not is all as it may seem. The aircraft with the one tank option had a tank in each wing carrying 63USG each, 237USG in the main, 170USG in the single drop tank, making for a total 533USG.

Aircraft that could carry two drop tanks had the wing tanks deleted, so they carried 237USG in the main and 170USG in each drop tank, total 577USG. A unknown portion of that extra 44USG would have been burnt overcoming the extra parasitic drag of the extra drop tank.

 

[nuuumannn]

Then what am I going to do with this box of Purina Groundhog Chow?

Makes a good addition to casserole...

 

[Greg Boeser]

Make sure you use lots of cream of mushroom soup.

 

[FLYBOYJ]

Not is all as it may seem. The aircraft with the one tank option had a tank in each wing carrying 63USG each, 237USG in the main, 170USG in the single drop tank, making for a total 533USG.

Aircraft that could carry two drop tanks had the wing tanks deleted, so they carried 237USG in the main and 170USG in each drop tank, total 577USG. A unknown portion of that extra 44USG would have been burnt overcoming the extra parasitic drag of the extra drop tank.

Although that makes sense but wouldn't that have been built into the charts found in the flight manual? How did you come up with 44 USG for parasitic drag?

 

[nuuumannn]

Make sure you use lots of cream of mushroom soup.

Ooo, handy tip... Thanks man!

 

[nuuumannn]

However, of the 875 aircraft involved, 348 delivered to USAAF, 30 USN, 20 Australia, 454 Britain, 23 New Zealand, slightly different to acceptances.

18 B-37 (January to April 1943),
1,600 PV-1 (December 1942 to May 1944)

It's worth mentioning at this juncture that the Ventura was designed by Lockheed for a British requirement and was subsequently adopted by the US armed services, as was the Hudson, whose design process began before the outbreak of WW2.

The Ventura was based on the Lockheed 18 Lodestar airframe as the Hudson was the Lockheed 14 Super Electra.

 

[nuuumannn]

Interesting, thank you for the additional clarification.
My suggestion about the Faber 109A-3 was based on the fact that it was the only fighter varient Fw 190 to be captured and evaluated by the western allies, the rest being configured as fighter-bombers. Or so Wikipedia would have me believe.
Are you aware if the NAFDU ever tested the Faber aircraft against FAA Hellcats or Corsairs?

It was the first intact Fw 190 that the British received, hence its significance as the Brits were worried about the type, as the copious letters by the Air Ministry around the industry attested to. The Fw 190 gets the credit for the high Fighter Command losses in 1941/1942, although most of those were caused by Bf 109Fs.

I dunno if it was tested against any FAA types, but it was flown to Farnborough in July 1942 where it was put in a demonstration fly-off for Air Ministry big-wigs against a Typhoon and "a" Spitfire. Test pilot Jeffrey Quill flew the Spitfire, which was the Mk.IV DP845 powered by a Griffon, although no one knew that at the demonstration - this was pre-arranged in secret between Joe Smith of Supermarine and Quill and so come demonstration day, the Spitfire ran away from both the fighters, leaving the assembled audience astonished as they had expected the Spitfire to be there as a standard performance fighter, not a specially modified example.

Needless to say, interest in a Griffon-engined Spitfire in countering the Fw 190 was high.

 

[wuzak]

Although that makes sense but wouldn't that have been built into the charts found in the flight manual? How did you come up with 44 USG for parasitic drag?

E emu27 was saying that there was 44 USG difference in fuel capacity between the two configurations, but some of that extra 44 USG would be burnt to compensate for extra drag of the extra drop tank.

 

[FLYBOYJ]

E emu27 was saying that there was 44 USG difference in fuel capacity between the two configurations, but some of that extra 44 USG would be burnt to compensate for extra drag of the extra drop tank.

I get that, I want to know how it was calculated. Was it based on the difference between the two configurations or is there a way this was actually calculated AND attributed to parasite drag?

 

[wuzak]

I get that, I want to know how it was calculated. Was it based on the difference between the two configurations or is there a way this was actually calculated AND attributed to parasite drag?

Seems to have just been the difference between the two configurations.

Configuration 1: 237 USG Main Tank, 2 x 63 USG outer wing tanks, 1 x 170 USG drop tank = 533 USG
Configuration 2: 237 USG Main Tank, 2 x 170 USG drop tank = 577 USG (no wing tanks available)

 

[FLYBOYJ]

Seems to have just been the difference between the two configurations.

Configuration 1: 237 USG Main Tank, 2 x 63 USG outer wing tanks, 1 x 170 USG drop tank = 533 USG
Configuration 2: 237 USG Main Tank, 2 x 170 USG drop tank = 577 USG (no wing tanks available)

Well that is not a way to calculate that 44 gallon difference was entirely from parasitic drag. I'll agree it could be a contributing factor.

 

[wuzak]

Well that is not a way to calculate that 44 gallon difference was entirely from parasitic drag. I'll agree it could be a contributing factor.

He didn't say that.

Simply, one configuration has 44 gallons more fuel than the other.

And using a second tank increases drag by an unspecified amount.