WWII Rate of Turns

Zipper730 · Feb 20, 2019

swampyankee

Okay, fps x pounds/horsepower*550? or (fps*pounds)/horsepower*550? I'm curious if this is derived from advance ratio or another formula?

swampyankee · Feb 20, 2019

Zipper730 said:
swampyankee

Okay, fps x pounds/horsepower*550? or (fps*pounds)/horsepower*550? I'm curious if this is derived from advance ratio or another formula?

(Fps time pounds)/(550* horsepower)

Velocity times force is equal to power, in ft-lbf/sec. Multiplying horsepower by 550 gives ft-lbf/sec

pbehn · Feb 21, 2019

pbehn said:
I thought you were discussing propellors?

A propeller produces thrust but it also suffers drag and creates sound and some heat itself. The resultant thrust of the whole propeller is what is used in thrust drag calculations for the aircraft itself. Unless you are precise with terms and units its difficult to actually know what you are asking about.

ODonovan · Feb 21, 2019

I'm coming in at the end of this, and don't have time to read through all the previous messages. Family aggro prevents that, unfortunately. I do want to leave a couple observations, for what they're worth.

P-47s were NOT bad turn fighters. See the battle over Asch Airfield (aka Y-29), during Operation Bodenplatte. The Germans lost 28 109s and 190s, some to American AAA, but 14 or more were actually air to air kills. The Americans lost one P-47 and no P-51s. This was in a low altitude turning fight around the slag heaps near the airfield.

A6Ms (Zero) could duck and dodge, but were not very good in sustained turns. They were built so lightly that at anything over about 6Gs, their wings would start to warp and could end up breaking off. That's also why they weren't very good in dives. People don't think much of the F4F Wildcat, but even in 1942 it had almost a 6:1 kill ratio, many of those being against the Zero.

-Irish

Elvis · Feb 22, 2019

Zipper730 said:
Since there are a couple of polls about what planes were the best dog-fighters, and in those days dog-fighting didn't just mean any close in fight with guns, but specifically fights that involved rapid turning.

I figure there's gotta be some way of organizing all of this data into a single source: I don't claim to know everything about WWII aircraft (I actually know fairly little), but from what I've gathered so far some of the best turning planes would include the following

Ki-43

A6M: Slightly less than the Ki-43

Hurricane: Unsure where it ranks

Spitfire: Slightly less than the Hurricane

There are of course many others, and many variables go into determining a plane's turning performance including the following

Weight: It decreases the responsiveness of the controls, affects maximum g-load at, and raises the corner velocity

The P-51/P-51A could turn inside the P-40 (which could marginally turn inside the Me-109) in typical combat trim; the P-51B/C/D if in a short/medium range layout would also demonstrate favorable performance (but across a wider range of altitudes), but if configured for long-range it was often inferior to the Me-109 except at higher speeds

There were proposals of fitting the Spitfire with slipper tanks and sending them off into combat for greater range: They even factored the performance in with full tanks and slipper-tanks partially emptied against the Me-109, though they ultimately didn't pursue it (probably because the best range required a cruise speed of 240 mph which would be dangerous against the Fw-190)

Altitude: Dictated by stall-speed, though without enough engine power it would mean there'd be inadequate thrust to keep the plane turning, and the slipstream might also be affected by the fact that with less engine power, there'd be less air blown over. The ability to fly at higher mach numbers might help to a point, but I'm not sure about that.

Exterior Stores: Drop-tanks, slipper-tanks, rockets, bombs, etc. All of these add drag in addition to weight.

I'd like to stick to the facts and avoid nationalistic debates and stick to the numbers: In this case, the facts lie in the numbers, so that seems the easiest way to go about it.

Tightest turning circle period

Tightest turning circle under typical speeds, weights & altitudes

Most rapid degree per second rate of turn period

Most rapid turning circle under typical weights, altitudes, speeds

I suppose there were some aircraft that weren't fighters that could turn surprisingly well because they were designed to fly at low speeds and things of that sort. Why not?

Somewhere, in some old obscure thread that I have yet to locate, there was a link to a website that included some tests the Russians did that helped them determine how good of a fighter the planes of the time were.
The test was how quickly they could navigate though a 180 degree turn at 2000(?) meters altitude.
I remember a number of the more popular fighters that are often quoted at this site actually didn't turn all that fast. I think most were in the upper teens to the mid 20 second range.
I seem to remember planes like the 109 and the P-51 did it in something like 22-25 seconds. The P40 and maybe the Spitfire were more in the 17-19 second range. One that did surprisingly well was the Brewster Buffalo (B239). It performed the task in something like 7 seconds.
I wish I could find the website that had that info, but have never been able to relocate it.
It could be that the site no longer exists, as the thread I saw that link in is over 10 years old now.
...anyway, those tests might be something to search for (could be they're mentioned at other websites) in compiling the information you require.

Elvis

Zipper730 · Feb 22, 2019

swampyankee said:
(Fps time pounds)/(550* horsepower)

Velocity times force is equal to power, in ft-lbf/sec. Multiplying horsepower by 550 gives ft-lbf/sec

And this gives pounds of thrust?

Shortround6 · Feb 22, 2019

The trouble (for me anyhow) is that these turn times are a snapshot out of a movie and a fuzzy one at that.

The British calculated a turn chart for the Spitfire I at 12,000ft

at a bit over 18 seconds in time the Spitfire was supposed to be able turn 360 degrees on a 1600ft radius (not diameter) at 6 Gs while doing 315-320mph (corrected.

at the other end of the chart it was supposed to be able to turn 360 degrees in the same time on an 800 ft radius at a bit over 3 Gs and doing a bit over 150mph.

Now a big problem is that the Spitfire could not actually do either one (or anything in between ) and maintain speed and/or altitude. Either speed would decline as the turn was made (increasing the turning time) or a downward spiral would have to be made in order to maintain speed.

See; http://www.spitfireperformance.com/spit109turn.gif

changes in engine, propeller, weight of aircraft and altitude (or more properly altitude density) will affect things.

Please note the curve marked "angle of straight climb" which pretty much marks the line between slowing down/descending and being able to climb while turning. The further above the line the more you have to descend to maintain speed. the further below the line the more you can climb while turning.

Shortest time for Spitfire (at 12,000ft) while maintaining height/speed seems to be about 19.5 seconds right at the edge of stall while pulling about 2.6-2.7 Gs on a just under 700ft radius.

BTW I would hazard a guess that the Buffalo in no way could manage a 360 turn in 7 seconds. I might well believe a misprint in which they left out a numeral 1 (17 seconds) which is still quite good.

Elvis · Feb 22, 2019

Shortround,

180 degrees, not 360.

Shortround6 · Feb 22, 2019

Elvis said:
Shortround,

180 degrees, not 360.

something seems off then, as the Spitfire and 109 could both do a 180 in 7-8 seconds if they bled off speed or altitude (or both).

If they maintained speed and altitude then they could do a 180 in 10-12 seconds (at 12,000ft not 2000 meters) and with lower powered engines unless the russians were testing an Allison powered Mustang.

I might but the B239 being able to out turn the later aircraft but out turning them by a factor of 3 takes an awful lot of swallowing.

Elvis · Feb 22, 2019

I know you're just trying to separate the BS from actual facts.
If you can find the thread and the link, please, post it here.
I even just tried to find the site and have come up with zilch, but I know I've been to that site and read the account myself, although a long time ago.
From what I remember, the planes simply came into the turn at 2000 meters and made a U-turn as fast as they possibly could.
Apparently, allied generals were on hand as well, to witness the event.
As for the B-239's accomplishment, it could be the factor of a lighter aircraft (less than 1/2 the weight of a P-51D) generating less stress (centrifugal force) on the frame (and wings) and thus, would be able to come into a turn harder and maintain that speed better.....of course, it also means less momentum, so one has to push the engine harder, but if the airplane is capable of doing it....

tyrodtom · Feb 22, 2019

ODonovan said:
I'm coming in at the end of this, and don't have time to read through all the previous messages. Family aggro prevents that, unfortunately. I do want to leave a couple observations, for what they're worth.

P-47s were NOT bad turn fighters. See the battle over Asch Airfield (aka Y-29), during Operation Bodenplatte. The Germans lost 28 109s and 190s, some to American AAA, but 14 or more were actually air to air kills. The Americans lost one P-47 and no P-51s. This was in a low altitude turning fight around the slag heaps near the airfield.

A6Ms (Zero) could duck and dodge, but were not very good in sustained turns. They were built so lightly that at anything over about 6Gs, their wings would start to warp and could end up breaking off. That's also why they weren't very good in dives. People don't think much of the F4F Wildcat, but even in 1942 it had almost a 6:1 kill ratio, many of those being against the Zero.

-Irish

The

ODonovan said:
I'm coming in at the end of this, and don't have time to read through all the previous messages. Family aggro prevents that, unfortunately. I do want to leave a couple observations, for what they're worth.

P-47s were NOT bad turn fighters. See the battle over Asch Airfield (aka Y-29), during Operation Bodenplatte. The Germans lost 28 109s and 190s, some to American AAA, but 14 or more were actually air to air kills. The Americans lost one P-47 and no P-51s. This was in a low altitude turning fight around the slag heaps near the airfield.

-Irish

The aircraft seems to always get the credit for accomplishments due to pilot skill.

A high % of the Luftwaffe pilots who were involved in the Bodenplatte operation were low time , inexperienced pilots, led by a few veterans, up against mostly experienced allied pilots.

A lot of those low time Luftwaffe pilots probably weren't capable of flying their aircraft on the ragged edge of it's flight envelope.

Bodenplatte was mostly a low altitude slugfest. Low altitude, hard turns. and low time pilots is a combination that kills a lot of people in general aviation even today.

swampyankee · Feb 22, 2019

Zipper730 said:
And this gives pounds of thrust?

This is the formula for efficiency; airspeed and power could be known, thrust would be solved for

CORSNING · Feb 22, 2019

Elvis,
I do not know what site the 180 deg./7 sec. for the Buffalo was posted on, but that
is the number for the Findland's B-239. This figure was for a speed of 349 km/hr at
2,100 m.
The following information is from Russian tests for a sustained 360 deg. turn at 1,000m.

Bf 109F-0 18 sec.
Bf 109G-2 20L/21.5R sec.
Hurricane IIb 20.5 sec.
Spitfire F. Mk. IX 17.5 sec.
Mustang I 23 sec.
B-239 15.8 sec./360 deg. @ 4,000 m.

I have put together 108 different models of A/C at 1000 m. and 77 different models of
aircraft at 4,000 m. The figures from 1,000 m. come from a few different sources mostly
from the Russian, French and Finish test. The figures I have at 4,000 m. come from Erik
Pilawlkii's aircraft compared book and are labelled, observed. Sorry I do not have time
to list them all at this time (to work at 5:00 a.m. you know). When I finally have a place
on a site to post all my aircraft performance material, I will make a special section for
these figures and post each with the perspective A/C models as I post.

Elvis · Feb 22, 2019

Thank you, Corsning. I was starting to think those nice young men in their clean white coats were coming to take me away (

)
I think you're citing a different test, though. It would make sense for a variety of tests to be done, probably on different occasions, too.
I'm sure I read that the test I'm thinking of was a U-turn (180 degrees) at 2000 metres.
The aggravating part is no one believes you until you can post something to back up your claim.....workin' on it.

Shortround6 · Feb 22, 2019

Elvis said:
The aggravating part is no one believes you until you can post something to back up your claim.....workin' on it.

It is not that I don't believe you read it, it is just so far off from the other aircraft that it boggles the mind.
See Cornsings figures. 2/3s of the time needed by an Allison Mustang is at least believable (not that the Mustang is the gold standard) and somewhat quicker most everything else.

It is when you get to 1/3 of the time needed by most of the other aircraft that things get really strange (the maneuverability of a UFO)

I have sure run across any number of misprints not only in books but in government manuals or government test results, some times you can guess what the number should be based on the trend,( numbers on either side).

Elvis · Feb 23, 2019

...and yet, Corsning quoted it right in the beginning of his post....

I do not know what site the 180 deg./7 sec. for the Buffalo was posted on, but that
is the number for the Findland's B-239. This figure was for a speed of 349 km/hr at
2,100 m.

Mind boggling as it may seem, there you go.
...and btw, Corsning, the B-239 IS the Brewster Buffalo. It's my understanding that "B-239" was actually Brewster's model/catalogue number for that particular airplane. The US Navy designated it F2A-1. I think the British came up with the name, as they were in the habit of using model names, rather than letter/number sequences.

Elvis

CORSNING · Feb 23, 2019

Elvis said:
The aggravating part is no one believes you until you can post something to back up your claim.....workin' on it.

Elvis,
It is very important to have reputable reference material to back your statements if possible.
That immediately takes a great deal of doubt out of your statement and gives some credence
to it.
As I have mentioned from time to time I had posted a lot of WW2 fighter information on another
forum before it went defunct. I tried very hard to make sure I listed all sources for the information
I posted so that the reader could make up his own mind the validity of my posts. If everyone just
posted their beliefs or partial facts from their memory we would not be able to collaborate the
correct information to find the truth, or as close to the truth as we can.

CORSNING · Feb 23, 2019

[QUOTE="Elvis, post: 1463014, member: 14526

Mind boggling as it may seem, there you go.
...and btw, Corsning, the B-239 IS the Brewster Buffalo.

I wouldn't be too sure about that. I believe the Finns referred to it as The Brewster. .........
I will now request the knowledge of the other members of this site to correct me if needed.

It's my understanding that "B-239" was actually Brewster's model/catalogue number for that particular airplane. The US Navy designated it F2A-1. I think the British came up with the name, as they were in the habit of using model names, rather than letter/number sequences.

That is correct.

Elvis · Feb 23, 2019

I used to have the story on the Buff (Aviation History, Nov.1996).
The Finns got the Buff because the salesmen at Brewster convinced the US Navy to invest in the new upgrade to the Buffalo, the F2A-2, just after they had bought the F2A-1.
So all the planes were pulled and replaced with the "latest and greatest" version.
Just so happened Finland needed to upgrade their air force due to a skirmish they were having with Russia over 50 acres of land each said belonged to them.
Brewster not only gave them the planes that had been in service with the US Navy, they also boxed up all B-239's that had been under construction and various parts that had yet to be assembled.
The only change Brewster made to that version was that they equipped them with an older style antenna, an older style gunsight and an international version of the R-1820 the plane used while in US Navy service (I wanna say it was the "G-205", but don't quote me).
Finland successfully used the plane for about two years. after which they were replaced with Bf-109's (although Finland was considered "neutral" during the war, they had a friendly alliance with Germany. In fact, it was the German's who guarded the port that the B-239's were originally brought in to).
In the end, both sides called a truce.
Finland annexed the 50 acres of land to Russia and in trade, the Germans stationed in Finland would have to leave, allowing the Russians use of that Port, unmolested (because it fell within the area of land that the Russians were after).
HOWEVER, the Russians were only allowed the use of that land (and the port) that was annexed to them. Thus, no "invasion" of Finland.
I think once that was all agreed to, the Finns bowed out of WWII and returned to neutrality.

Elvis

Elvis · Feb 23, 2019

CORSNING said:
Elvis,
It is very important to have reputable reference material to back your statements if possible.
That immediately takes a great deal of doubt out of your statement and gives some credence
to it.
As I have mentioned from time to time I had posted a lot of WW2 fighter information on another
forum before it went defunct. I tried very hard to make sure I listed all sources for the information
I posted so that the reader could make up his own mind the validity of my posts. If everyone just
posted their beliefs or partial facts from their memory we would not be able to collaborate the
correct information to find the truth, or as close to the truth as we can.

I understand what you're saying and it makes perfect sense.
I wasn't asking you to take me on my word alone, I was only stating how aggravating it is to know the information is out there and I can't find it to cite.
I kinda feel like the sane guy who was mistakenly placed in the insane asylum and all records of the court proceeding showing my sanity have disappeared.

Elvis

WWII Rate of Turns

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