Ok, help me out here.

[Vermillion]

*looks at weazel and nods his head*

INCOMING !!!!

*dives in a handy bunker*

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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"

[wells]

hi laz,

What I really found interesting was the difference between the 1C and 1D in a sustained turn.  The 1D definitely turned slower for some reason.  I think airframe drag is way overdone (both pitch and yaw) and the sustained turn speeds are about 50 mph slow as a result.  For example, there are tests that show a Spitfire IX has a sustained turn speed of 180 mph, a 109; 200 mph, the La5 can turn some 20 deg/sec sustained.  It's only about 13 in AH.  The turn rate threads are around here somewhere...

[Jekyll]

If you want to see how this thread is likely to turn out, go here
 http://agw.dogfighter.com/agw/Forum3/HTML/012193.html

You've got AH and Warbirds covered lazs, is there still a forum for Air Warrior?

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C.O. Phoenix Squadron
http://www.users.bigpond.net.au/phoenix
'feel the heat .......'

[Westy]

NO, Jekyl  

[-lazs-]

Hehee weaz and verm... of course, if it wasn't obvious... I wouldn't notice it.  I did want the answer tho and it is as bad as i suspected.

Wells, how can they be so complete on the climb and speed stuff and get this kind of turn rate figures?   Does the airframe drag affect the planes in some lopsided way or is there some other reason that causes these odd results?
lazs

[wells]

I dunno lazs, I'm trying to figure that out!  150 mph should give about 2G's in the turn, whereby the radius would be 215m (90 degree bank) or 250m for 60 degree bank (2G).  I'm getting 340-350m, which only corresponds to about 1.4 G.  There's 2 things I can think of...

1.4 just happens to be the square root of 2, so maybe there's something wrong with the math code, or...

They are subtracting lift produced by the tail.  While this is ok, it only really applies when the elevator is first deflected.  As the angle of attack increases, the tail approaches it's zero-lift angle, so this effect may be way overdone and is probably the reason for the 'handles like a truck' comments.

[hitech]

Wells a few things you might not be considering.

1. Thrust portion due to aoa helping you around the turn goes down with increase in speed.

2. Lift on horz stab debends on where the cg as to which direction and how much of the tail helps the turn.

3. Prop was % over wing changes with speed.

HiTech

[wells]

 

1. Thrust portion due to aoa helping you around the turn goes down with
            increase in speed.

Ok, but speed isn't changing, it's constant in a sustained turn.  If anything, the G force should be higher from the propwash as compared to the power off stall speed.

 

2. Lift on horz stab debends on where the cg as to which direction and
            how much of the tail helps the turn.

I realize that.  How can a tail that's only 18% of the wing area, account for a 30% loss in lift?  The tail doesn't appear to be helping at all and what it takes away is WAY too much, even for the most stable of planes.

[hitech]

Well's Im confused what your trying to figure out based on what numbers. Can you outline your numbers for me?

HiTech

[wells]

Hitech,

Use the F4u for example:

Clean stall = 102 mph
Sustained turn (stall) = 145 mph
G-force in turn should be about 2.0, right?

(145/102)^2

The turn radius for such a turn works out to 215m (for 90 degree bank) and about 250 m for 60 degree bank (2G).  

I"m measuring a whopping 340-350m turn radius at 200', which is a corresponding 1.4 G's.  So basically, I guess I'm trying to figure out why the G force is so low and why the radius is so large?  

[Jochen]

I just compared sustained turn values between AH and WB (from Hoof's site) and here are the results.

Plane........AH......WB...... .......Diff %

Spit V.......24......15.3......... ..156
Spit IX......25......16.3......... ..153
109F-4.......28......17.9...........156
109G-6.......29......20.............145
P-38L........29......15.9.(P-38F)...314
P-51D........31......20.5...........151
109A-8.......31......23.1...........134
F4U-1D.......33......20.............165

Fw 190A-8 is the winner and P-38 is the loser in this lottery.

WB results are with 10 internal fuel while Wells did run his AH tests with 100% internal fuel I guess?

Somehow almost systematical 150 % percent difference in most cases feels odd. Are WB planes too good in sustained turning or AH planes too poor in sustained turning? The truth is out there... What we realle need is accurate sustained turn data or calculations.

Wells, Hitech, do you guys have any ideas?

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jochen Jagdflieger JG 2 'Richthofen' Aces High
jochen Geschwaderkommodore (on leave) Jagdgeschwader 2 'Richthofen'  Warbirds

Thanks for the Fw 190A-5 HTC!

Ladysmith wants you forthwith to come to her relief
Burn your briefs you leave for France tonight
Carefully cut the straps of the booby-traps and set the captives free
But don't shoot 'til you see her big blue eyes

[This message has been edited by Jochen (edited 05-25-2000).]

[Vermillion]

Jochen, to compare the two they would have to be done with the same amount of fuel.

And this is exceptionally hard too do, because in WB's, they include drop tanks as "internal fuel".

Here is an example, just working the numbers in my head, but if Im counting right, the difference in 10% fuel in a P-51 and 100% fuel (no drop tanks) in a P-51 is something like 1,000lbs-1,500lbs of weight. This would definitely effect turning performance.

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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"

[This message has been edited by Vermillion (edited 05-25-2000).]

[-lazs-]

Shouldn't a lighter plane turn even better?
lazs

[wells]

Here's the thread with turn time data.  It's mostly for 109's and Russian planes.
 http://bbs.hitechcreations.com/smf/Smileys/default/Forum9/HTML/000402.html

On average, I got 120% better results in WB (100 fuel).  The exceptions are also the 190a8 (only 7% better in WB) and the P-38L (35% better).  Relatively, the 190 has gotten better in AH and the 38L worse, compared to the other planes.

[This message has been edited by wells (edited 05-25-2000).]