WWII Rate of Turns

[CORSNING]

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.

I have felt that feeling many times my brother. You just have to take a deep breath, spend the time
and research the truth to the best of your ability....and post where it came from so the knowledgeable
on this site can help you through it.

All the best, Jeff

 

[eagledad]

Corsing and Elvis

Attached is a file of turn times for various fighters. The data was provided by members either Juha or Jukka (I think) I do not want to slight the indivdual(s) that provided the data and comments.

FYI

Eagledad

 

[Shortround6]

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).

That is not quite how it is laid out in AHT but the truth maybe somewhere between the two accounts?

The Navy had placed an order for 54 F2A-1s on June 11 1938.

On march 22 1939 the Navy orders the conversion of the XF2A-1 prototype to XF2A-2 standard (maybe the Brewster salesmen were wining and dining the Navy brass?)

June 20th 1939 sees the first production F2A-1 rolled out and delivered.

July 1939 sees the work done on converting the XF2A-1 to XF2A-2 standard and fight tests start.

August 1939 sees the British stick their oar in the water.

August 1939 also sees the Poland order 250 F2A type fighters.

Dec 1939 sees 11 F2A-1s having been accepted by the US Navy (Brewster delivering late as would become usual)

the remainder of the 54 plane order (43 aircraft) are released to Finland using commercial engines. 9of the Navy planes are put into service with VF-3 aboard the Saratoga.

Dec 1939 sees the Dutch place their first order and Jan sees the British reverse course and order 120 panes (later increased to 170)

Brewster delivers 17 aircraft in jan 1940 and 27 in Feb and they are shipped to to Sweden where they are assembled and test flown by SAAB at Trollhatten.

It took until April for all the 239s to reach Finland.

Dutch and British aircraft take precedence over US Navy deliveries and it is not until Sept of 1940 that deliveries of the replacement aircraft to the US Navy began.

After 43/44 F2A-2 aircraft are built production changes back to the British 339E.

The US Navy orders 108 F2A-3 in Jan 1941 because Grumman is slow delivering F4Fs, BUT Brewster does manage to rework eight of the Navies F2A-1s to F2A-2 standard (they did not go to Finland?) in May of 1941. Production of the F2A-3s starts in June with first aircraft accepted in July 1941. Production will run into Dec 1941/Jan 1942 at which point it switches to the Dutch 439 model but none are delivered before the Dutch East Indies fall.

I have no idea which account in more correct (Germans guarded Swedish port? or planes where unloaded and assembled somewhere else?)

I don't really want to play the 'my source is better than your source' game.

however.

Caption (from wiki) says "LT John S. Thach tipped this F2A-1 onto its nose on Saratoga, March 1940. "

The engines used in the F2A-1 and the Finish planes were R-1820G series engines. Which are quite different than G-100s or G-200s (changed from aluminium crankcase to steel crankcase, etc) the last number (as in G5 or G 205) designates things like supercharger gear ratio or some other difference. And this is where it gets more than a little difficult to figure out who got what.
Wright would put the letter "G" in front of the engine designation if the engine was fitted with a reduction gear as in GR-1820G2 and leave if off if the engine was direct drive, R-1820G2 for example. The Military didn't make that distinction in the basic designation but had more model numbers at the end as in R-1820-40, which is actually (I think?) a GR-1820-205A.

For the R-1820 (at least the early ones) it seems the last digit of "2" signifies a 7 : 1 ratio is used in the supercharger drive. the digit "3" signifies an 8.31 : 1 ratio and the digit "5" signifies a two speed supercharger with a low ratio of 7.14 : 1 and a high ratio of 10.0 : 1

again please note that this is for the civil designation, no such simple code exists for the military engines.

 

[Elvis]

Shortround,
Not saying your info is incorrect, but I never cited any dates, so what are you debating with all the bold dates?
Thanks for the reminder on the engine designations. I do believe now it was the R-1820-G5 (not G205) that went to Finland with the rest of the B-239's.
As far as I can remember, I have never found (or heard of anyone else finding), a source to prove that 8 F2A-1's were left with the Navy, so that picture speaks loads.
Thanks also for posting that. Interesting that 8 were left behind. Maybe an oversight?
As for the port that the B-239's landed at, that was a Finnish port that was run by the German's (apparently there with the Finn's blessing).
Interesting interaction there, too. German run port accepting a shipment from USA due to sendee being the Finns.
….truth is indeed, stranger than fiction.

 

[CORSNING]

Corsing and Elvis

Attached is a file of turn times for various fighters. The data was provided by members either Juha or Jukka (I think) I do not want to slight the indivdual(s) that provided the data and comments.

FYI

Eagledad

Thank you Eagledad. Juha posted that list on this site some time ago and I added some of his
information to my list. I had done pretty much the same thing as Juha collecting from several
sources and putting them all together. Finding information for 4,000 m. was a plus. Juha should
be commended for his efforts.

 

[P-39 Expert]

Corsing and Elvis

Attached is a file of turn times for various fighters. The data was provided by members either Juha or Jukka (I think) I do not want to slight the indivdual(s) that provided the data and comments.

FYI

Eagledad

Fascinating. The P-47 certainly didn't turn very well. Admittedly 1000m was not exactly it's wheelhouse.

 

[CORSNING]

Fascinating. The P-47 certainly didn't turn very well. Admittedly 1000m was not exactly it's wheelhouse.

It would be very interesting to know all the ww2 aircraft's turn times at 30,000 ft./9,000 m.
The story was a very different one up there for the P-47 and its beautiful R-2800 engine.

 

[Zipper730]

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.

Isn't that basically a level-turn? I'm amazed by how people can complicate such simple things to the point that it becomes incomprehensible.

 

[Zipper730]

Efficiency is defined as useful work out divided by energy in. For a propeller, that would be airspeed (in feet per second) times thrust (in pounds) divided by (horsepower multiplied by 550) or, equivalently, airspeed (in meters per second) times thrust (in newtons) divided by power (in watts).

Would this mean that 80% of the theoretical maximum power ends up emerging as actually power/force/thrust?

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

Okay... let's start at the basics: I have a bunch of data from WWII Aircraft Performance on the Hawker Hurricane Mk.I & II's

In some cases, there are pieces of data that's missing: I'm trying to fill in the gaps to the best of my ability to determine how much thrust is being produced overall. Apparently I need to know horsepower in some cases, the speed in other cases (there are gaps in the data). I know the propeller diameter in all reference cases.

I've been told speed can be graphed pretty reasonably in a linear fashion -- not sure if that's true, but if I provide the data -- can somebody help me fill out the gaps?

 

[Zipper730]

I was looking at .doc by E eagledad , about turn-rates measured by the USSR in WWII. Does anybody know what speed these turns were entered at? Some cases seem to indicate a turn-radius, so that's not too hard; others have no indicated radius, which makes determination of speed impossible.

BTW: BiffF15 X XBe02Drvr Would the tightest rate of turn be at the corner-velocity?

 

[XBe02Drvr]

BTW: BiffF15 BiffF15 X XBe02Drvr Would the tightest rate of turn be at the corner-velocity?

Yes. It's all explained here:
Corner Speed
Cheers,
Wes

 

[Zipper730]

Yes. It's all explained here:
Corner Speed

Okay, so as an estimate, you'd use compute power-on stall speed * square root of g-load right?

 

[XBe02Drvr]

Okay, so as an estimate, you'd use compute power-on stall speed * square root of g-load right?

Don't ask me. Read the reference in its entirety, and if that's not good enough, google corner velocity. There's all kinds of stuff out there for you to find, so go find it instead of trying to get everybody to spoon feed you. If what you find raises questions, THEN ask the x-spurts.
Cheers,
Wes

 

[Zipper730]

Don't ask me.

Don't worry, I found the answer on another page on this site. It turns out, I asked this before, but forgot about it. You were actually the person who answered -- turns out power-on was not the speed figure to use, so I guess I'll just compute with power-off.

 

[Zipper730]

Dean did some calculating of his own regarding the turn radius of various US fighters in America's Hundred Thousand

These numbers don't look right, now I could be wrong: I'm looking at stall speed x square root of g-load, and the P-61B's 1g stall speed @ 27000 lb. is 106 mph power off clean, flaps down is 88-89 mph if these figures are right, and I put a speed of 97-1/3 to 100.2 as a maneuvering flap setting if it even had one.

I get the following for 3g stall

• 183.6 mph flaps-up, power-off
• 153.6 mph flaps-down, power-off
• 168.6 - 173.6 mph flaps part-down, power off

The square root of 3 is 1.732050807568877

 

[Zipper730]

There's another flight manual on the P-61, and while there are slight variations in the stall speed, they're fairly close.

 

[Elvis]

Efficiency is defined as useful work out divided by energy in. For a propeller, that would be airspeed (in feet per second) times thrust (in pounds) divided by (horsepower multiplied by 550) or, equivalently, airspeed (in meters per second) times thrust (in newtons) divided by power (in watts).

Sorry to resurrect this part of the thread, but I'm curious....why are you multiplying HP by 550? What does 550 represent?
Thanks in advance.

Elvis

 

[XBe02Drvr]

Sorry to resurrect this part of the thread, but I'm curious....why are you multiplying HP by 550? What does 550 represent?
Thanks in advance.

Elvis

550 foot-pounds was how much work James Watt originally calculated one standard issue horse could accomplish in one point zero measured seconds.
Doesn't anybody teach history of technology anymore?
Cheers,
Wes

 

[pbehn]

550 foot-pounds was how much work James Watt originally calculated one standard issue horse could accomplish in one point zero measured seconds.
Cheers,
Wes

It was a Scottish steam horse.

 

[swampyankee]

...and Watt was performing marketing. Horses are about 50% more powerful than that.