corner velocity

[Murdr]

Originally posted by Widewing
Recently, I was testing climb rate in the F4U-4. I fired the guns while climbing and the climb rate dropped by about 1,000 ft/min! I guess they are modeling recoil.

My regards,

Widewing

Yea, that force was very easily observed with the con plane this past year.

[Schutt]

Originally posted by Widewing
Corner velocity can be roughly estimated for each type by doing a simple test.

Take off climb to at least 1,000 feet. Level off and accelerate to about 300 mph.

Pull into a turn, cranking in more G until your vision is limited to a small hole in the black... You are now at approximately the plane's corner velocity. If you open E6B and center the speed read out, you will be able to see IAS and TAS.

I've done this with the P-51D and F6F-5 and it is very close to published corner velocities for these fighters. It's a good rule of thumb at least.

Note that you will not be able to sustain corner velocity for more than a few seconds without turning nose down.

My regards,

Widewing

Widewing, i dont fully understand the  test procedure. When i try that in 109K4 i can get the tunnel at 290mph IAS and hold it till about 258 IAS. That is for 50 % fuel. Now, is the corner velocity at the last point i can hold the tunnel before falling into the stall (~260), where the tunnel vision can no longer be pulled since i stall out or at the 290?
Also, i thought with the K4 it should be worse to the right than to the left, but i couldnt find out any diffrence with that method, probably because i am to hamfisted.
What is the corner velocity that you get for the 109K4 with that method (at 50% fuel)?

regards, schutt

[df54]

I know this has been mentioned before but what we really need is EM
charts for all ah planes. This would be a monumental task and I don't see it happening any time soon.

[Mace2004]

Originally posted by Schutt
Widewing, i dont fully understand the  test procedure. When i try that in 109K4 i can get the tunnel at 290mph IAS and hold it till about 258 IAS. That is for 50 % fuel. Now, is the corner velocity at the last point i can hold the tunnel before falling into the stall (~260), where the tunnel vision can no longer be pulled since i stall out or at the 290?
Also, i thought with the K4 it should be worse to the right than to the left, but i couldnt find out any diffrence with that method, probably because i am to hamfisted.
What is the corner velocity that you get for the 109K4 with that method (at 50% fuel)?

regards, schutt

I take the plane over 300 and then do a max g level turn, stick full aft.  Before doing the test I move the e6b to the center of the screen so you can see it just when you come out of blackout.  I get 170 for the K4.  Direction of turn has no impact on corner velocity since it's an issue of G vs stall speed.  Also, this proceedure is based on the assumption that complete blackout occurs right at the maximum g limits for the airframe but I'm not positive this is so.  I'm going to do some other checks later today.

[Badboy]

Originally posted by Balsy
where are accurate AH2 charts available that state cornering speed?

Hi Balsy,

You can read the corner velocity from EM diagrams like this one. That diagram is accurate and up to date. It was produced for the recent Battle of Britain Scenario, with EM diagrams for the fighters from Sea Level up to 30k feet.



Notice that the corner speed seen here is less than the value quoted by Mace2004 and that is because the corner speed isn't constant, it varies with the configuration/weight of the aircraft and the diagram above is for a clean configuration, 25% fuel, War Emergency Power, and no flaps. As the aircraft gets heavier, the corner speed gets higher, drop flaps and the corner speed gets lower.

Here is an older one I did for the Ki-84 and F6F:



You can find the original Battle of Britain analysis here:


Battle of Britain Scenario Analysis

I have produced EM diagrams like those for quite a lot of the aircraft in the game, but many of them are no longer current. Unfortunately I don't produce them at a very high rate these days. But I think it would be good to do a complete set of these diagrams, so I think I may enquire about a little help.

Badboy

[Murdr]

Originally posted by Mace2004
Also, this proceedure is based on the assumption that complete blackout occurs right at the maximum g limits for the airframe but I'm not positive this is so.  I'm going to do some other checks later today.

Pilot G tolerence is constant regardless of airframe, though as I understand it there are varibles that affect the conditions that a G-lock occurs.  Structual G limits are individual to each respective plane model.

[Schutt]

Intresting i think i understood the method now.

It seems that during the short term black outs (when you black out but instantly come back to tunnel vision) the controll forces are still applied, so while holding the stick full back the airframe starts making noises and stops again during blackout. That i would take as indication that i am pulling more gs during the black out than what i see when going in and out of it.

By shifting my view around i managed to keep the g meter in the center of my sight. It seemed to me that the deep tunnel vision is around 6.6g and the total blackout at 6.8-7.0. I tried that in 109E4, P38, P51, 109k4 and with what murder said and i heared from others, i assume its equal for all planes. I thought that i read due to seat design / pilot position some fighters would allow higher g than others, when considering the same pilot.

I tried to measure with above method as a comparison the point for the 109E4 with 25% fuel and that method yielded around 235 mph for me, while badboy lists 215. Now i tend to think the method delivers the value at 7g?

[Mace2004]

Based on the numbers I've recorded and extrapolating Badboy's data it does appear that using the "blackout" test method for determining corner is providing a speed for about 7G.  The good part of this is that with the additional G we should be generating better numbers than the chart indicates and it appears to be the case.  The published G limit is based on a percentage of the total airframe load limit and provides a safety margin plus extends the life of the airframe.  By being able to push an extra G in AH without paying a damage and/or an airframe lifespan penalty means we're free to operate at the limit of our blackout.  When you think about it, that's probably true for combat ops anyway, as I seriously doubt that someone about to be gunned is going to look at his G-meter and stay at the limit when he can pull more.

[Gooss]

To add to the blackout test:

Didn't HiTech say that the speed at which the stall buzzer became loudest during the blackout test was the corner velocity, approximately?

I've found that pretty consistent at different altitudes using IAS as the indicator.

HONK!
Gooss

[Murdr]

Originally posted by Mace2004
By being able to push an extra G in AH without paying a damage and/or an airframe lifespan penalty means we're free to operate at the limit of our blackout.  When you think about it, that's probably true for combat ops anyway, as I seriously doubt that someone about to be gunned is going to look at his G-meter and stay at the limit when he can pull more.

In one of my books, there is a letter written home by a Chris Herman saying that he had flown with both McGuire and MacDonald in a couple of flights and he now needed a new plane because both of his P-38 wings were sprung and wrinkled trying to keep up with each "Mac" during their respective missions.

[Murdr]

Here is verification on pilot G limit.

Originally posted by hitech
All black outs occur at the same G. At what speed you can pull enough G's to black out varies greatly between planes.

[NitroFish]

Thanks Mace, Widewing, Murdr and Badboy.
This thread is the best and most helpful me in my 7 months of Aces High.


NitroFish (CPR)