Corsair Turning Ability in AH

[Knegel]

Just will bring this up again, maybe someone is out there who is able to explain if and why the Ah flaps dont work ok, or at least why the F2A test results with/without flaps differ so much from the AH results(with/without flaps).

If noone is able to do it, this is maybe something for the bug forum.

Greetings,

Knegel

[ForrestS]

I just wanna say that this airplane is AWSOME!!!

I was playing in the H2H arena and NoobFire introduced me to it. I usally fly the Mustang and the Lightning. But the F4U-4 is NICE. It goes really fast and turns nice. And it can land on Carriers.

[SteveBailey]

Originally posted by dtango
Here are some diagrams.  Equations to come later.

Based on Newton’s laws, if a force constantly acts perpendicular to the path of a moving object, the object will move in a circular path at constant speed.  The following diagram graphically depicts this.  This is fundamental physics.



Guess what?  Lift is a force perpendicular to the path of a moving airplane.  If you remove gravity as you suggest and you have a 1G lift force, the 1G lift force constantly acts perpendicular to the airplane.  The next diagram depicts the results.





Tango, XO
412th FS Braunco Mustangs

This would be pretty but does not account for the forward thrust of the aircraft. A plane flying in "no gravity" would not loop as lift is only one force working here.

[dtango]

Steve:

I'm assuming (a) T=D, and (b) there is a forward velocity v as pointed out on the diagrams.

If there wasn't any forward velocity then the plane would go straight up.  

Tango, XO
412th FS Braunco Mustangs

[dtango]

Knegel:

I don't know what else to tell you.  To prove that the AH FM is incorrect you have to prove that it is violating:

Ps = (T - D) * V / W

You haven't done that yet.  It's much more complicated than it looks.  The catch is how this relationship varies in 1g flight vs. >1g flight.

Tango, XO
412th FS Braunco Mustangs

[HoseNose]

I know I'm going to sound rather stupid, but I'd like to point out that the F4U only seems to turn extremely well (initially as i might add) or as Knegle has said 'out of hand' because of the combat trim.

The CT causes a large upward trimming motion while the flaps come out and while the plane slows down. When your flaps are all the way down and your trim is all the way up, the F4U doesn't feel as much as the uber turner it once was at 180 - 250 mph. Besides, in many of the other flight sims out there, the Corsair seems very tail heavy even at speeds of 170 mph, so trimming up would simply make it turn tight during the actual execution of the trim. Add flaps to that and you got one nice turner.

Just my pair of Lincoln heads.

[Saxman]

Really, trim doesn't do much to affect the F4U's turning ability. It doesn't actually make it turn any tighter. All combat trim is design to do is keep your attitude level (minimize drift/yaw, roll and pitch away from level flight).

Kicking in combat trim gives the illusion of improved turn/pitch performance, because if your plane is out of trim (let's say, so that your nose is trimmed down) and you turn on combat trim, all the sudden your nose pops up because CT automatically corrects, not because it's making you turn tighter.

[F4UDOA]

Knegel/Hosenose,

Does this help at all? The F4U-1/4 can pull 2G's (instantanious) at 110Knots (126MPH) at 12,000LBS no power/no flaps. The CAS/IAS chart for the F4U shows no error at that speed so that is a real number. When power is applied the stall number comes way down as airflow increases over the wing from the prop. In postwar test of the F4U it could reach 3G's with no flaps at just over 100Knots IAS. These are examples of turning without flaps.

With flaps the drag from the flaps can be used to slow the airplane from higher speeds however the thrust/drag curve starts to change at lower speeds the parasite drag from the flaps becomes less of a force and the lift is more powerful especially when combined with the airflow created from the 2,000HP up front. Evident of this is the ability to take off with a 4,000LBS payload. If the drag was more powerfull than the lift the airplane could not takeoff in such a loading condition.

IMHO what should happen is what does happen: as you add flaps and turn you slow from 170MPH down to 110MPH when you no longer deccelerate and you seem to accelerate through the turn because your lift and thrust far exceed the drag and G force being applied at low speed.

So basically the flaps add drag at low speed but not enough to overcome 2,000HP and the lift of the wing and flaps which is also considerable.

[HoseNose]

Originally posted by Saxman
Really, trim doesn't do much to affect the F4U's turning ability. It doesn't actually make it turn any tighter. All combat trim is design to do is keep your attitude level (minimize drift/yaw, roll and pitch away from level flight).

Kicking in combat trim gives the illusion of improved turn/pitch performance, because if your plane is out of trim (let's say, so that your nose is trimmed down) and you turn on combat trim, all the sudden your nose pops up because CT automatically corrects, not because it's making you turn tighter.

Well, theoretically, the upwards trimming motion seems to increase the elevators' upward pitch. If you look closely, the elevators move upwards as you trim up even though your stick is already fully up. So just theoretically, the up trim should do something while it's in the process of moving up.

In real life, we have actual tabs, which unlike in IL-2 and AH:II are smaller control surfaces that actually move upwards instead of having the actual elevators 'going up' even further (I'm sure you know, but I'm just saying to reinforce my point). This thus 'curves' the elevators even more producing an even tighter turn. I'm still young and I have a lot to learn, however  so correct me if I'm wrong

[Benny Moore]

That's wrong.  The trim tabs in reality actually move opposite of the direction they move the elevator.  Thus they theoretically work against the elevator in terms of maximum deflection, rather than adding to it (though the amount is so tiny that it doesn't really matter).  In short, you would actually get more elevator deflection by trimming full down and fighting the trim by pulling the stick all the way back (assuming you had enough strength, which is doubtful).

I say that everyone who has not personally used trim tabs on a real airplane should refrain from attempting to describe them, because those people invariably get it terribly wrong.

[Benny Moore]

Originally posted by Brooke
I think the F4U and its flaps probably work correctly, but it might be that other aircraft (the P-38 for example) are not as close.  Here is an analysis:

http://www.electraforge.com/brooke/flightsims/aces_high/stallSpeedMath/stallSpeedMath.html

Could you explain further?  I assume that you mean that the P-38 should possibly have more lift, either turning better or having a lower stall speed.  As this is something I've long suspected, I'm very interested in hearing what you have to say about it.

[Krusty]

In AH we don't have trim tabs, we have pressure on the stick in the cockpit.

Hosenose, it doesn't work that way. Hitech has explained that trim is only within the bounds of max deflection. If a stick's max deflection is N degrees, then max deflection with max trim is still N. Trim only helps in cases when not using max deflection, in this game. It makes stick forces lighter, not greater.

[Benny Moore]

Aces High II's trim is as realistic as a simulator can get it.  Unfortunately, commercial simulators cannot replicate real trim unless everyone has precise joystick which mechanically match the physical gaming stick angle to that of the virtual stick's.  It would also thus have to be able to withstand any pressure that a user could put on it, meaning about two hundred pounds.

All real trim does is move the position at which the stick will return to if you let go of it.  It doesn't increase or decrease maximum elevator deflection at any time.  It only decreases the amount of strength required to reach that deflection.

[HoseNose]

Originally posted by Benny Moore
Aces High II's trim is as realistic as a simulator can get it.  Unfortunately, commercial simulators cannot replicate real trim unless everyone has precise joystick which mechanically match the physical gaming stick angle to that of the virtual stick's.  It would also thus have to be able to withstand any pressure that a user could put on it, meaning about two hundred pounds.

All real trim does is move the position at which the stick will return to if you let go of it.  It doesn't increase or decrease maximum elevator deflection at any time.  It only decreases the amount of strength required to reach that deflection.

Oh I see. thanks for posting that out guys ... well. I've got a lot to learn. So in real life, the 'negative trim' could actually help you turn better, but not in AHII, correct due to Krusty's explanation of N being maximum deflection in-game.

Well, let's sit back, grab some popcorn and continue watching these guys argue. I can't help but to wonder what conclusion we'll have.

[Knegel]

Originally posted by dtango
Knegel:

I don't know what else to tell you.  To prove that the AH FM is incorrect you have to prove that it is violating:

Tango, XO
412th FS Braunco Mustangs

Hi,

tell me why the F2A test show a so much different result.

Greetings,

Knegel