P38 Performance

[Baloo]

On another note, this was all brought up with planes catching up to me or climbing up to me...and yes, I mean when we are at equal energy states. Try out running a Spit16. Maybe pilots are disguising their state well, but sometimes I know there's just no way.

[GScholz]

No, not significantly, some is synonymous with little...where as significantly is synonymous with big

Significant is also synonymous with measurable, noticeable, observable, perceivable, perceptible, pronounced, recognizable, substantial, tangible...


In other words: It makes a difference.


And if you're at equal energy state against a Spit16 you're in big trouble in a P-38 at anything less than top speed or very high altitude. The Spit16 can build energy like crazy and out-accelerates and out-climbs just about anything..

[morfiend]

On another note, this was all brought up with planes catching up to me or climbing up to me...and yes, I mean when we are at equal energy states. Try out running a Spit16. Maybe pilots are disguising their state well, but sometimes I know there's just no way.

 Alot of this is easily explained but unless you have film of a specific incident it would just be guessing and assumptions in any explaination.


    

[GScholz]

Baloo have you actually checked the relative performance of the P-38L and Spit16?




And on top of that it has much lower wing-loading so it turns better and bleeds less energy in turns.

[Baloo]

Alot of this is easily explained but unless you have film of a specific incident it would just be guessing and assumptions in any explaination.


    

I'll start running films, good advice.

[morfiend]

I'll start running films, good advice.

  Do you see the post above,the performance figures alone show how it's quite possible!

  With film you can see your speed and alt and the enemies,you can also see where any corners were cut to shorten the distance and any mistake you or the enemy might have made.

  I will admit I dont film,I never have and likely never will,but then I blame myself when I get shot down not the other guy!


   

[Drano]

Significant is also synonymous with measurable, noticeable, observable, perceivable, perceptible, pronounced, recognizable, substantial, tangible...


In other words: It makes a difference.

Now that's just backpedaling. ANY drag is measurable, etc.,--does that make it a significant ammount of force? Does that small ammount of drag make a difference? Certainly it does--just not in the sense that you think it does. That flap is not going to slow you down---at all. Don't believe me. Try it for yourself. Take a 38 up to say 10K and let the speed stabilize. Now hit the flap. You won't slow down at all---at ALL. Maverick isn't gonna hit that flap and make the bad guy fly right by. If that's the strategy he's dead. Now you can take any other plane in the game that has a dive flap on it and do that same flight and once you hit that flap it's gonna slow right down. Why? Because they're different flaps designed for different purposes. One is a brake the other is not. It's just not. Give it up.

[GScholz]

It is significant enough that they mentioned it in the text. If you think those flaps and the disrupted airflow they create won't produce significant drag then you're deluding yourself. Not my problem though...

"DIVE RECOVERY FLAPS.—P-38L and Later P38J
airplanes are provided with dive recovery flaps to improve
the dive recovery characteristics of the airplane.
As described above, the airplane without these flaps becomes
very nose heavy and starts to buffet above placard
dive speeds. This condition is caused by a high speed
stall and a consequent decrease in lift in the wing producing
the nose heavy condition. The dive recovery flaps
which are installed under the wings between the booms
and the ailerons, restore the lift to this portion of the
wing and thus cause the uncontrollable nose heaviness
to occur at a higher speed. The flaps also add some drag
to the airplane, which in conjunction with the higher
allowable dive speed, permits safe dives at a much steeper
diving angle. The dive recovery flaps should be extended
before starting the dive or immediately after the dive
has started before a buffeting speed has been reached. If
the airplane is buffeting before the dive recovery flaps
are extended, the buffeting will momentarily increase
and then diminish. With these flaps extended, the nose
heaviness is definitely reduced but the diving speed
should never be allowed to exceed the placard by more
than 15 or 20 mph. With the dive recovery flaps extended
before entering the dive, angles of dive up to 45° may
be safely accomplished. Without dive recovery flaps extended,
the maximum angle for extended dives is 15°.
Diving characteristics are better with power off than
with power on."

[Drano]

It is significant enough that they mentioned it in the text. If you think those flaps and the disrupted airflow they create won't produce significant drag then you're deluding yourself. Not my problem though...

I don't need to read that 30 times. I know what the flap is and what it does. That's what I meant when I said this:

"Does that small ammount of drag make a difference? Certainly it does--just not in the sense that you think it does. That flap is not going to slow you down---at all."

[GScholz]

That flap is not going to slow you down---at all."[/b][/size]

And that is where I call BS. Anything protruding into the airflow will slow you down, and certainly something as uncompromisingly flat and disruptive as that flap.

[Drano]

Just because you don't know doesn't make it BS. I challenged you up the thread. Try it for yourself then come back. Hell post a film! That's how sure I'm right.

Hint: it won't slow you down in a dive either.

IT'S NOT A DIVE BRAKE

And That ain't no BS!

[Baloo]

IT'S NOT A DIVE BRAKE

And That ain't no BS!

Yea, that is true. I remember when I first started flying the 38 and thought just the opposite, grumbling about how the "dive brake" is a bunch of BS as I depended on it to get me out of a compression and ended up as a poor excuse for a tree...then after actually trying to learn the 38 is when i discovered that all it was meant to do was help you recover better. The following quote pretty much reiterates what Drano has been explaining to you, but maybe someone else's words may work better?

As noted in another reply, the only way you'll see the dive flaps deploy is if you're on the runway and hit F3 and look under the plane as you deploy them.  You will not see them deploy sitting in the cockpit.

The dive flaps work as intended and will assist in recovering from a high speed dive.  The problem with a lot of players is that they usually deploy and use the dive flaps incorrectly.  A lot think that the flaps are intended to help you recover from a dive by acting as a brake and slowing your plane down enough that you can pull out of a dive.  That is 100% incorrect.  As you can see in the diagram below and in the photo with the dive flaps deployed, the dive flaps are a very inefficient design to act as a dive brake, why?  Well, that's an easy answer because the dive flaps weren't designed to act as brakes but instead as someone else mentioned to change the airflow over the leading edge of the wings.

(Image removed from quote.)

(Image removed from quote.)

For the dive flaps to work properly, you need to be in a certain window where they are beneficial to get the most out of them.  The dive flaps only work at high speeds, they are pretty much useless at speeds below 350mph IAS and you won't see any real effect if you deploy them at speeds lower than that.  The best time to deploy the flaps is when you're about to enter the dive, though you can sometimes get away with deploying them shortly after you've started your dive.  New or inexperienced P-38 drivers tend to deploy the flaps at the onset of a high speed buffet and by that time it's usually too late and the dive flaps aren't as effective and you'll need to manually trim to recover.  As soon as you complete your dive recovery, retract the dive flaps.

A little trick you can do with the dive flaps that was used by real life P-38 drivers.  The dive flaps can aid in high speed turns, just deploy them at the start of the turn and retract them as you finish the turn.  

Now the brutal honest truth...if you have to deploy the dive flaps to recover you messed up.  It's that simple.  Properly flown, the P-38 (all models) can safely dive if you understand what compressability is and how it effects the P-38 without neediing to use dive flaps.  Remember, compressability happens when the air over the leading edge of the wing reaches critical mach speeds, which means the higher you fly the P-38, the increased risk of entering compressability in a dive.  The lower you fly the P-38, the risk decreases dramatically the lower in altitude you go.  In other words, the P-38 will not enter into a compresability state below 20,000ft, the air is too thick for the air over the leading edge to reach critical mach.  The P-38 will suffer from sluggish and hard controls below 20,000ft but that is due to regulary aerodynamic forces pushing on the control surfaces and not the phenomena that is compressability.  

To safely dive the P-38, you need to control your speed and you can do that by decreasing throttle and using your rudders to "skid" the plane in the dive.  Using this simple technique you can easily reach speeds up to 475mph IAS in a dive and still retain control (although sluggish) to pull up out of the dive without having to use dive flaps.

Why?  They don't do anything at low speeds and even if they did wouldn't be smart to deploy them on landing.  Besides, you don't need flaps to land a P-38.

ack-ack

[GScholz]

Just because you don't know doesn't make it BS. I challenged you up the thread. Try it for yourself then come back.

I just did and you're absolutely right! They produce no noticeable reduction in top level speed. I find that totally incredulous and have posted a bug report about it. http://bbs.hitechcreations.com/smf/index.php/topic,360029.0.html

This must produce drag!

[Drano]

You're right it does produce drag. I never said that it didn't!  But it doesn't act as you think. The drag produced merely deflects the airflow in a way that helps to control the plane at high speeds. A low speeds it is totally ineffective. Slowing down isn't really the idea as it would be in a dive bomber where their flaps are applying a ton of drag by design. In those you want to slow down so you can aim a bomb accurately before you hit the target with your plane! Which would screw up your whole day! The P-38's a fighter so you want to go fast---but you need to be under control too. After augering a few lightnings they went to the wind tunnel and found the problem was with the action of the airflow on certain parts of the plane--the elevator in particular--at high mach numbers. At first they thought it was a balance problem with the elevator. They attempted to fix it with a counter balance--that's what that little thingy is on the center of the elevator. That didn't help but they kept it on there anyway thinking it wasn't a bad thing to have. But it was this deflection of the airflow by the recovery flap really helped solved that problem and it was added to later J models as a field mod and to the L's afterward as a factory installation.

Of course you can still get yourself going too fast! I screw up all the time.

[GScholz]

They don't produce any drag noticeable by the instruments in the game. They must produce a lot of drag. It must be a bug. There is no way you can place a flat "plank" that size almost at a right angle to the wing surface and not have it produce a lot of drag.