A Critical Analysis of the RAF Air Superiority Campaign in India, Burma and Malaya in 1941-45

[Juha2]

A pilot who was at Java described a Hurricane coming in to land when some Oscars suddenly appeared and set the Hurricane on fire. The pilot pulled up to about 800 ft and bailed out successfully. The Oscar then pulled up sharply and broke up.

That is not the only case in which Oscars were seen to break up in a dive.

Yes, that is true for early Oscars, Japanese needed to reinforce the main spar of the early Oscars.

 

[Kevin J]

In fact Soviet pilots were not very fond of Hurri and at least over Artic it was an underdog against 109Fs or even against FiAF's Brewster B-239s. Of course the skills of pilots had marked effects on the results of the air combats. And the armament of 2 x 20 mm and 2 x 12,7 mm was effective.

Juha

At least they were scoring victories.

 

[fubar57]

166 victories by my count, no Soviet aces in Hurricanes

 

[Glider]

IMHO that was Kurfürst's opinion on Spitfire not on the 45 Impgal slipper tank.

Juha

That's a name from the past. Not a big fan of the Spit, or anything else that wasn't a 109

 

[fubar57]

That's a name from the past. Not a big fan of the Spit, or anything else that wasn't a 109

I just saw him on another site, not a fan there either. Can't recall the dates

 

[RCAFson]

Thanks for the source, even if I knew the docu beforehand. But who hell would use 5 lb stick force, except maybe badly wounded pilot, in a life and dead situation? The 30 lb or more is much more realistic for real life combat situation.

Juha

When you look at gun camera footage, roll rates are typically not extreme, and the responsive roll rate with low stick forces was a nice feature. Extreme dogfighting is actually pretty rare.

My main point was that Spitfire and Hurricane roll rates were nearly identical, which is true, so on the NACA868 chart:

http://www.wwiiaircraftperformance.org/naca868-rollchart.jpg

The Spitfire (normal wing) is going to be nearly identical to the HurrIcane.

The Hurricane was also shown to have excellent (comparatively) rolls rates in Flying to the Limit, data from which was posted earlier in the thread [post 129].

 

[Juha2]

When you look at gun camera footage, roll rates are typically not extreme, and the responsive roll rate with low stick forces was a nice feature. Extreme dogfighting is actually pretty rare.

I agree that low stick forces was a plus in any fighter.

My main point was that Spitfire and Hurricane roll rates were nearly identical, which is true, so on the NACA868 chart:

http://www.wwiiaircraftperformance.org/naca868-rollchart.jpg

The Spitfire (normal wing) is going to be nearly identical to the HurrIcane.

Yes when also Hurri had metal ailerons, Mk Is had fabric covered and at least the late Mk IICs seems to have had metal covered ailerons. Weight distribution along the span also had its effects on how fast the roll began.

The Hurricane was also shown to have excellent (comparatively) rolls rates in Flying to the Limit, data from which was posted earlier in the thread [post 129].

Thanks for pointing the message #129 to me, have been away and read only the first 100 posts before jumping to the last ones. Very interesting!

Juha

 

[Greyman]

Yes when also Hurri had metal ailerons, Mk Is had fabric covered and at least the late Mk IICs seems to have had metal covered ailerons. Weight distribution along the span also had its effects on how fast the roll began.

I don't think the Hurricane ever had metal ailerons. It was tried briefly when it was also experimented with on the Spitfire, but unlike the Spitfire, it was found there was no benefit.

 

[Schweik]

Have you source for that? because following graph says something different.

This matches my understanding. It also lines up a lot better with this NACA 868 chart RCAF posted (and everyone keeps posting)

 

[Schweik]

Wow that didn't come out right let me try again,

Hawk/Hurricane/Spitfire/Buffalo

asi/ time to 45 degrees/force

200/2.2 sec , 8lb /1.3sec,10 lb/1.8sec,10lb/1.7sec,10.5lb
250/2.3sec,14lb/1.4sec,15lb/1.8sec,18lb/1.7sec, 14lb
300/2.sec7, 20lb/1.5sec ,21lb/2.1sec, 35lb/1.7sec, 17lb
350/4.0sec, 27lb/1.6sec, 38lb/2.6sec, 55lb/1.8sec ,20lb
390/5.5sec ,33lb/1.9sec, 34lb/3.5sec, 80lb/1.6sec, 24lb

It sounds like the hurri had relatively light control forces, which is not the same thing as saying that roll rate was good. This also doesn't match the claim that the Spit and Hurri had similar roll rates.

As for gun camera footage - a lot of what little we typically get to see shows planes being finished off after already having been damaged. Relatively little gun camera footage is actually released and easily accessible - usually on TV shows etc. (and on youtube) they so the same 5 or 6 clips over and over.

From what the pilots describe, combat maneuvering was often very violent. It wasn't unusual for people go go into spins (sometimes intentionally) and they routinely describe 'slamming the stick' around the cockpit especially when trying to escape.

S

 

[slaterat]

It sounds like the hurri had relatively light control forces, which is not the same thing as saying that roll rate was good. This also doesn't match the claim that the Spit and Hurri had similar roll rates.

That roll rate I posted for the spitfire, is for a MK1, before the metal ailerons were added. Its the Spit 5 and later that were similar to the Hurricane which is what the chart you posted shows.

The NACA 868 chart shows the spit out rolling the p 40, up to 250 ias, at 50 lbs force.

I guess roll rate is not as simple as one might think.

 

[Greyman]

I guess roll rate is not as simple as one might think.

For sure. There are potentially a lot of 'ifs', 'buts' and fine print when an aircraft's roll characteristics are described in a single word.

Thanks to Juha for jogging my memory and getting me on the right track re: NACA Spit/Hurrie testing ...

The ailerons of the Spitfire and the Hurricane airplanes were less effective than the ailerons of the P-40 airplane at high speeds because the large control forces limited the obtainable aileron deflections. For small deflections, however, the ailerons of the British fighter airplanes were very light and responsive. Many pilots were very favorably impressed with the aileron characteristics because of this fact. A true picture of aileron characteristics was obtained only after tests were conducted under simulated combat conditions where large aileron deflections are required. - NACA

 

[Schweik]

For sure. There are potentially a lot of 'ifs', 'buts' and fine print when an aircraft's roll characteristics are described in a single word.

Thanks to Juha for jogging my memory and getting me on the right track re: NACA Spit/Hurrie testing ...

The ailerons of the Spitfire and the Hurricane airplanes were less effective than the ailerons of the P-40 airplane at high speeds because the large control forces limited the obtainable aileron deflections. For small deflections, however, the ailerons of the British fighter airplanes were very light and responsive. Many pilots were very favorably impressed with the aileron characteristics because of this fact. A true picture of aileron characteristics was obtained only after tests were conducted under simulated combat conditions where large aileron deflections are required. - NACA

yeah I remember this from a previous discussion in another forum years ago (long before we had so many helpful documents available) about roll rate of some other planes. There is roll acceleration and roll rate at different lbs force, and roll rate at different speeds and also at different altitude. I remember the P-47 rolls very well at 25,000 ft but no so great down at 5,000 ft.

So yeah it's complex. My biggest question right now is how was the roll of the Spit V and Spit IX etc., more like one above with the Hurricane down around 65 degrees per second or more like in the NACA 868 chart where it's up at 105 degrees per second at 200 mph.

Which of the two charts (if either) represents a Spitfire with metal ailerons? What is the explanation of the discrepancy between the charts?

And is there a clear equivalent chart for the Bf109? From this report it sounds like the Bf109 had a pretty poor roll compared to the Spit and Tempest, but equal to the P-51.

S

 

[Greyman]

Ok .. new chart with the new data:

Roll velocity in degrees per second, speeds in IAS. All stick forces 30 pounds.
A6M3 Type 32 (RAAF data)
Spitfire (RAAF data)
Spitfire V (NACA)
Hurricane II (NACA)
F4F-3 (NACA)

The two Spitfire curves are there to illustrate the inconsistency of roll performance on similar aircraft. Something I've run into many many times looking at roll performance.

 

[slaterat]

For comparison sake I researched some performance numbers for the planes in this discussion. I know there are varying sources and numbers available but the concept here was just to help illustrate overall trends and tactics. I used primary sources when possible, a lot from this website.
Speeds at altitudes

KI 43-1 sea level 273/3k274/6,560ft 286/10k305/16k 306/max308@13k
zero sea level 270/5k287/10k305/16k336/20k321/25k315/30k306/max336@16k
Trop Hurri sea level265/5k280/10k296/15k310/20k333/25k/324/30k300/[email protected]
P-40C sea level???/10k314/15k331/20k326/25k321/[email protected]
P-40D sea level???/2k298/4k305/10k329/15k341/20k330/[email protected]

Climb rate
KI 43-1 5.5mins to 16,405ft(5000m)
Zero sea level 2,750/15k 2,380/20k 1,810/30k 850/time to 20k 8.11
Trop Hurri sea level 2,800/5k 2,480/10k 2,150/15k 1,710/20k 1,510/30k 680/time to 20k 10 min/time to 30k 17.2min
P-40C sea level 1960/13.5k 1,960/20k 1,360/30k 140/time to 20k 10.8/time to 30k 25.9min
P-40D sea level ???/2k 1,570/12k 1,580/16k1,220/20k 870/28k 160/time to 20k 14.25 min/time to 28k 33.5min

 

[Zipper730]

The ailerons of the Spitfire and the Hurricane airplanes were less effective than the ailerons of the P-40 airplane at high speeds because the large control forces limited the obtainable aileron deflections. For small deflections, however, the ailerons of the British fighter airplanes were very light and responsive. Many pilots were very favorably impressed with the aileron characteristics because of this fact. A true picture of aileron characteristics was obtained only after tests were conducted under simulated combat conditions where large aileron deflections are required. - NACA

The British were light at low speed but became so heavy at high speeds that they were nearly useless?

Ok .. new chart with the new data:

View attachment 499436

Roll velocity in degrees per second, speeds in IAS. All stick forces 30 pounds.
A6M3 Type 32 (RAAF data)
Spitfire (RAAF data)
Spitfire V (NACA)
Hurricane II (NACA)
F4F-3 (NACA)

The two Spitfire curves are there to illustrate the inconsistency of roll performance on similar aircraft. Something I've run into many many times looking at roll performance.

Weird the discrepancies? What would you say would account for them?

 

[Greyman]

Weird the discrepancies? What would you say would account for them?

Differences in manufacturing seems to me to be the biggest culprit. One example I pointed to here.
A change in lubrication made a big difference in Hurricane roll performance at low temperatures.
Different testing/measuring methodologies could be the cause, or the condition of the aircraft (internal/external equipment, modifications).

 

[slaterat]

Looking at the performance envelopes one can draw several conclusions.

The P-40D is the fastest below 20k and has a 20 to 30 mph advantage at low level for escape. The six .50s give it excellent firepower for fast slashing attacks. However it is the worst in the climb making, getting good( diving) position for intercepts difficult.

The P40-C has similar options to the P40-D just not much as much of a margin although it does have a better climb rate perhaps making a better interceptor than its big brother. Both these two struggle to get to 30k.

The Hurri 2, although it doesn't dive quite as fast as the P40s, it still dives faster than the KI 43 or Zero and it has a much better chance of getting to altitude, to use that diving advantage than the P-40s. It is faster than both its Japanese opponents above 17.5k. The tough spot for the Hurri is combat below 10k. Here it is slightly slower than the two Japanese fighters and in a co e situation without backup will be a difficult extraction.

 

[Juha2]

The British were light at low speed but became so heavy at high speeds that they were nearly useless?
Weird the discrepancies? What would you say would account for them?

It's about how one definite "high speed" and "nearly useless". According to the NACA 868 table Figure. 47 Spit with normal wing still had the ror little under 60 deg/sec at 407 mph TAS at 10 000 ft. Note that the speeds in the table are given as IAS.

One reason might be that Spit and Hurri, like Fw 190, had Frise type ailerons, which were suspectible to rigging errors. And of course we are talking about war time products when quantity was more important than quality.

 

[Juha2]

I don't think the Hurricane ever had metal ailerons. It was tried briefly when it was also experimented with on the Spitfire, but unlike the Spitfire, it was found there was no benefit.

Thanks a lot for that, I tried to veryfy that from my sources but from Finnish sources only got the info for Mk I and for Mk II cannot find quickly anything better than a cutaway from a 1987 Aeroplane Monthly, which published a four part article on Hurricane in April - July 1987 issues. The Mk I cutaway rightly showed fabric covered ailerons and the Mk IIC cutaway claimed metal ailerons.

Juha