1. Exchange copied from : http://www.ww2aircraft.net/forum/flight-test-data/roll-rate-30407.html 

Gentlemen,

I try to guess the roll rate of major WWII aircraft on the following scale :
0 : very bad (less than 10/s)
1 : bad (about 20-30/s)
2 : poor (about 50/s)
3 : average (about 70-80/s)
4 : good (about 100/s)
5 : very good (about 120/s)
6 : outstanding (about 150/s)

At the first sight I would go for :
(0) : floatplanes and seaplanes, multi-engines bombers.
(1) : most twin engine fighters (Bf110, Mosquitto, Beaufighter), A6M2N, single engine dive and torpedo bombers, some hot twin engine light bombers (A-20G ?).
(2) : early P-38, P-39, F6F, A6M2, Hurricane I/II, Spitfire I, Boomerang.
(3) : Bf109, late war P-38, F4F-3/4, A6M3/5, Spitfire II & VB, P-36
(4) : P-40, P-47, Spitfire VC
(5) : F4U, Spitfire MkIX
(6) : Fw190

What do you think about that ? Would you change some things ? How would you rate the following planes :
- US : P-35, P-43, P-51, F2A-3
- Fr : D.520, MS.406, MB.155.
- It : CR.32, CR.42, G.50, MC.200, MC.202, Re.200, Re.2001, re.2002.
- IJA : Ki.27, Ki.43, ki.44, Ki.45, Ki.61.
- IJN : A5M4, J1N, J2M.
- FAA : Fulmar, Gladiator, Skua
- NL : D.XXI, G.1A

Thanks for any help,

Francis 

 


 

Francis,

Roll rates vary considerably with speed. If you take just the F4U-1 Corsair (See: http://www.wwiiaircraftperformance.o...4u-1-02155.pdf), the rates of roll during tests (overload fighter, 273 gallons of fuel in fuselage tank, wing tanks empty, full aileron deflection) l, were as follows:

1) right roll: 70 / sec, clean, 150 mph; 84 / sec, clean, 200 mph.
2) Left roll: 70 / sec, clean, 150 mph; 76 / sec, clean, 200 mph.

So your prediction of 120 / sec for the F4U is nearly twice what the aircraft was capable of ... at 150 and 200 mph, with no fuel in the outer tanks. Fuel in the outer tanks will make it roll slower. As a rule, very few WWII fighter could exceed 90 / second. Each must be researched individually, and the rate changes consideraly with speed.

If you want to do a fun simulation, have at it. If you want a realistic simulation, you need to carefully read performance reports from WWII. The thing is, they tested what they tested, not necessarily what we want to know today. They figured, for instance in the report above, that testing the rate of roll at 150 and 200 mph was enough to characterize the aircraft. But what about 400 mph and above? Not shown in the report, and you cannot assume it gets higher because most WWII aircaft rolled slower after reaching some max roll speed that varied by a lot between aircraft types. To be complete, the report also characterized the roll rate in landing configuration at 90, 150, and 200 mph, but that is not a configuration you would use in combat.

The Me 109, for instance, was a pretty good roller at 250 mph. But at 420 mph it was pretty solid in both pitch and roll, and the stick could not even be moved more than about 1/4 deflection to either side due to aerodynamic forces and a very narrow cockpit, making application of much force to the stick a problem. The 109 was designed for combat at 180 - 280 mph and it was a bit out of its element at 350+ mph.

From: http://www.spitfireperformance.com/spit1vrs109e.html :

The Me 109E could roll 45 in 1 second at 200mph, but the same roll at 385 mph took 4 seconds.
The Spitfire Mk I could roll 45 in 1.9 seconds at 200 mph, but at 385 mph it took 3.8 seconds.
It looks like the roll rates of the Me 109E (or Bf 109E) and the Spitfire Mk I were equal at about 330 mph, with the 109 rolling better when slower and the Spitfire rolling better when faster. Neither is anywhere near your projected roll rates above.

Don't go with opinons, go with documented tests. If you can't find them, then making assumptions will render the simulation not vey realisitc, though it still could be fun. Apart from NACA 868, there are several other sources of comparative roll performance:

The NACA also did a comparison of early Spitfire, Hurricane, P-40 and P-36 rolls rates across various speeds.

There are a few other lateral control tests of the period with comparative roll rate tests. The RAF did roll rate tests for the Tempest V, Spitfire Mk XII and Mustang X - all of these are available online, most at Mike William's Spitfireperformance.com/ww2aircraftperformance.com.

There is Joe Smith's lecture on the history of the Spitfire, which gives roll rates for the Mk V with various types of aileron hinge and different types of skinning at various speeds. He also compares Spitfire Mk I, V and XXI roll rates.

There are some German tests of Bf 109G roll rates - I think they are available on Kurfurt's 109 site.

There is an graph of RAAF tests with Spitfire, Typhoon, Mosquito, various Mustangs, P-40 (Tomahawk), Boomerang and Hamp rolls rates. There is also a RAAF test comparing P-40 roll rates with the Spitfire V and Zero, although I can't recall if these are across the speed range or just peak values.

There is a German test of 109s and 190s against various Italian types that gives some commentary on comparative roll rates. The Italian aircraft generally rolled slower than 109s.

Data on Soviet, Italian and Japanese aircraft is generally harder to come by. Most of the information we have (at least, in the English speaking world) comes from the comparative tests of the air forces of the various western powers on captured aircraft. Therefore, there can be no guarantees as to the accuracy of the tests - look at the problems the USN had with FW 190 roll rates in their comparative tests with the F6F/F4U. With the help of "Mrs Sills Sea Sick Pills" Boone Guyton spent many hours in roll tests with the Corsair. Eventually, at combat speeds, throwing the stick hard against the full stop would roll the airplane more than 180 degrees per second. And the stick force was light. Page 85, "Whistling Death" by Boone Guyton. I've never seen a US Navy report listing the Corsair as anywhere near 180 per second at any speed.

Then again, I haven't read them all yet either.


Can anyone supply a link to such a report? If you read Dean's "America's Hundred Thousand" he says that there were many reports of the high roll rates exhibited by the Corsair but only scanty test data available about that roll rate. The Corsair was a continual work in progress and unlike many other WW2 AC the later models always had better performance than the early models. In Guyton's book, there were many, many test flights to improve the Corsair's roll rate. I don't doubt Guyton's statement about the one second-180 degree roll but that was probably under optimum conditions( light fuel load, no guns or ammo, no external stores, best direction to roll) and I would not expect the operational Corsairs to be able to do that well. However, there are many reports about the beautiful ailerons of the Corsair. I rolled an L39 twice at 250 knots TAS. It's published roll rate is >300 degrees/second @ 250 knots and I don't doubt it. The Corsair was eventually fitted with boost tab ailerons, as was the P-38.
This would increase the rate of roll.
I've heard the Corsair was one of the better rollers, matching Fw190.
A lot of that also depends on airspeed and stick force. The very late Corsairs ... F4U-5 and later, didn't make WWII and the F4U-4 didn't fully equip even one Naval squadron until 4 months before the end of the war. So, the bulk of F4U Corsairs used in WWII were F4U-1 models, with the 85 - 90 per second roll rate. Improved versions , with much hgher roll rates, showed up at or after the end of the war.


I added this simply because Francis is trying to do a simulation and might as well use the values that were true for the bulk of the war, and maybe allow faster speeds and roll rates only when the date is later than an introduction date for such an improvement for a specific type. Actually I believe the Corsair which was considered the nicest flying was the F4U4. It was just barely a WW2 fighter. However the improvements that were made on the Corsair, such as ailerons, seat height , landing gear bounce, right wing spoiler, cowl flap actuators, canopies, water injection, etc. were ongoing and not always limited to the latest model to go into production. A four second 360 degree roll was considered quite good in WW2. I believe that comparative tests of an F4U1 and a FW190A4 showed them to be equal in roll. A couple of notes on your roll rate figures:

Bf 109E versus the Latter Me 109F/G/K. The entire Me 109 series had ecellent roll rates at low/medium speed which reduced at high speed due to aileron stiffening.
However from the Me 109F onwards a new wing with "Friese" ailerons was fitted to reduce the control loads and so the Me 109F/G/K must have had a higher roll rate at speed.

The Spitfire Mk 22 received a new wing structure to increase roll rate since the thin single spar Spitfire wing would twist and tend to reverse the roll under some situations of high speed.

The P-51A had a modest roll rate however from the P-51B on 'internal balancing' was fitted which used pressure from control surface deflection to pressurize a bellows to reduce loads and this aircraft developed a high roll rate. Worked well with the thick laminar profile wings which had space for such things.

P-39 and P-63 had a high roll rate, the P-63 (with laminar profile) probably the fastest US roller of the war, P-40 also had a high roll rate.

Late war Hellcats and Corsairs had geared spring tabs added to reduce control forces improve high speed roll rate (at the expense of low speed roll rate)

The FW 190D-12, a few saw service, received hydraulic boosted ailerons, it was intended to fit this to the Ta 152 as well. The Do 335 also had hydraulic boosted ailerons.

Me 262 and Arado 234 used spring tabs to reduce aileron loads. For their future jets (P.1101, P.1112, Ta 183) the Germans though they might need hydraulic boosted controls.


Gentlemen,



I have gathered from several sources (post on various forum, NACA documents, books and websites, etc.) some data and I rated some aircrafts :

Fw 190, Spitfire VIII : best roll rate is 150/s 
and more
Spitifre VC, Spitifire IX, F4U-1, P-40, G50, MC200, MC 202 : +/- 100/s
 
Spitfire VA, P-38L : 90 /s
F2A-3, F4F-3/4, F6F-3, P-38J, P-39, Ki.61, Boomerang, Hurricane I & II, Spitfire I : 60-70/s
 
P-38F, Mosquitto, Me 110 : 40/s


What do you think about ?

Unfortunately, the data I found for some aircrafts is not homogeneous :
Bf 109 : I have 45, 80 or 110/s ;
A6M2 : I found 55 and 80/s at slow speed ;
A6M3 : my sources say 80, 90 or even 110/s
P-51 : from source to source, best roll rate comes from 60 to 100 /s via 75 and 90/s
P-47, which is known as a great roller is rated 70, 80, 100 or 120 /s

Would you mind help me picking the 'good' number please ?

Last, I wonder about the best roll rate of biplane fighters such as Gladiator or CR42. Good or bad ? I know tey had very low WL but a good roller is not always a good roller.

Once again, thank you very much for your help.

Francis
The data you have is of fairly limited in terms of comparisons as it stands because it is incomplete, we need to know at what speed the roll rate was measured since it varies dramatically between types at various speeds. In addition there is a big difference between and Bf 109E and an Me 109F.

There is a roll rate chart here.
http://www.wwiiaircraftperformance.o...-rollchart.jpg

Of course all aircraft improved as the war progressed and I believe even FW 190 came with ailerons optimized for particular speeds.
The roll rate changes with speed so it decreases from the best rate at 180 - 250 mph down to 15 to 50 per second at 440 mph+. At 500 mph, most WWII planes cannot roll much at all.

90% of all WWIII fighter roll rates start slow, build to a peak roll rate at 180 - 250 mph (not knots) ans taper off to 10 to 50 per second or less at 480+ mph. The 50 is maybe for the Fw 190's best rolling. The rest are under 30 per second at 480+ moh and it decreases with speed until comrpessibility ... then they just dive into the ground, as very many did, American, Grman, British, Italian, and Japanese.

Nobody had 500+ mph figured out until the Me 262, and it was placarded at 540 mph ... and STILL is when they fly one. If the pilots fly faster, and the CAN with modern engines, they become test pilots ... in an airframe that usually hits the ground if it goes faster.

Its been some time but i thought all American pursuit planes (P-38, P-47, P-51) had a peak roll above 300mph.
Roll inertia would be another category.


Some did. like the P-51.

Not many people realize it, but the P-51 had three aileron stops, at something like 9, 11, and 15. the maximum roll rate depends on which stop your ailerons have.

At the Planes of Fame Museum, I believe "Wee Willy" is set to the middle stop, and I'm not too sure about "Spam Can," but will find out this weekend.

Anyway, the P-51 generally rolled better up until about 350 mph or so, and that was unusual in WWII fighters ... most were slowing down at that speed.

The Zero was very bad at rolling, but was almost unbeatable at pitch rate ... at lower speeds.

A unique aspect of the so called "Laminar Profile" wings of the P-51 was they were relatively thick compared to other wings and that thickness was at about 50% of chord not 25% as is typical.   This is where the P-51 stored its prodigous fuel.   It also left room in the wing for internal pressure balancing: if the aileron was deflected up the pressure at the wing aileron hinge line was channeled to a bellows to reduce aileron forces.     Internal balancing was added to the P-51B, the P-51A did not yet have that facility.

That's because IJN aerial doctrine emphasized stall fighting at speeds of 150 mph. Why they thought that way when even early model A6Ms could achieve 330 mph in level flight is a good question.

dave I read that this requirement came from pilots requesting manoeuvre characteristics similar to the A5M, I know the listed requirements for the A6M were combat range and manoeuvre, combat flaps were added to the model 21, the original A6M in limited production were land based preproduction versions given to pilots in China for service evaluation. It maybe that the belief at the time was that low speed handling was more important than high speed manoeuvres with the presumption that enemy aircraft won't be doing 400mph in level flight. In China they dominated late-30s fighters but pilots requested more manoeuvrability and regarded speed as superfluous.

I read Italian pilots had similar leanings, some squadrons switched back to biplanes from Fiat monoplanes in 1940 because they were dissatisfied with the faster fighter's manoeuvre characteristics. They determinedly felt that aerobatics trumped speed. They learned better the hard way, like Mitsubishi did but the main reason for the fairy build of the Zero was for range, not manoeuvre. It was literally stripped to break long distance flight records, then shoved into combat with only guns fitted. Strip a Wildcat like that and it won't do combat so good outside its element either, as it was put an ace in a Zero and Wildcats will fall like autumn leaves.
Perhaps so for acrobatic superstars like Saburo Sakai and Hans-Joachim Marseille. Unfortunately such people comprise only about 1% of pilots. You need to create aerial tactics and build fighter aircraft that allow the other 99% to succeed. That's what made the Me-109 and Spitfire so good during the early 1940s. They could boom & zoom while still being quite acrobatic in the hands of an expert.

Refering back to the NACA reports mentioned earlier on this Lateral Control thread. :

Summary of Lateral-Control Research NACA-TR-868
Summary of Lateral-Control Research NACA-TN-1245
Lateral Control by Spoilers at the DVL NACA-TM-1307

These reports, though post-dating the war by several years, are applicable to this forum as the research was done during it. Searching TN-868 will only interest those meaning to get an understanding of metals at impact velocities. Regards
A LITTLE WW2 TABLE BASED ON VARIOUS FORUM READING - IT IS ASSUMED THESE ROLL RATES ARE AT "BEST COMBAT SPEED"
 /sec > 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 110 120 130 140 150 160 170 180 190 200 250 300 350 400
S361                                                                    
Bf109E                                                                    
F4U1                                                                    
F2A3                                                                    
F4F4                                                                    
F6F3                                                                    
P38L                                                                  
P39                                                                    
P40                                                                    
P47D                                                                  
P51D                                                                  
P63C