Author Topic: P-38 dive flaps produce no drag  (Read 11863 times)

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #120 on: March 22, 2014, 01:28:28 PM »
Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.


Except that it defies the laws of physics. It is quite impossible for the dive flaps to not produce drag, at any air speed.
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #121 on: March 22, 2014, 01:39:28 PM »
Except that it defies the laws of physics. It is quite impossible for the dive flaps to not produce drag, at any air speed.

Is it no drag or is it so small, it can't be measured in the game?  You assume the drag is sufficient to be detectable.  Maybe it is not.

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #122 on: March 22, 2014, 01:49:18 PM »
It is impossible to fly at 300+ mph and put something like that into the under-wing airflow and not have it slow the plane down noticeably. Even a single empty weapons pylon slows a WWII fighter down by several mph. The Fw 190A-5 for example loses 9 mph of its SL top speed by carrying an empty centerline bomb pylon.
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #123 on: March 22, 2014, 01:56:19 PM »
It is impossible to fly at 300+ mph and put something like that into the under-wing airflow and not have it slow the plane down noticeably. Even a single empty weapons pylon slows a WWII fighter down by several mph. The Fw 190A-5 for example loses 9 mph of its SL top speed by carrying an empty centerline bomb pylon.

It would seem that way but we have nothing as fact or antidote to support your claim.

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #124 on: March 22, 2014, 02:01:11 PM »
You consider the fact that the P-38 pilot's handbook says they produce "some drag" to be, what... "nothing"?

If there is insufficient data to model them accurately they shouldn't have been added in the first place.
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #125 on: March 22, 2014, 02:11:49 PM »
You consider the fact that the P-38 pilot's handbook says they produce "some drag" to be, what... "nothing"?

If there is insufficient data to model them accurately they shouldn't have been added in the first place.

I do think if the number was significant, a stronger warning would have been made.  Again it would against operating procedure to leave them on all of the time or pilot error.

Do you know HTC doesn't have the data?

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #126 on: March 22, 2014, 02:18:33 PM »
If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.

It is difficult to know what data HTC has since they so far have chosen not to comment on the issue.
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #127 on: March 22, 2014, 02:33:07 PM »
If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.

It is difficult to know what data HTC has since they so far have chosen not to comment on the issue.

Still you have no facts just assumptions guesses.  Keep in mind I also have zero facts to say the model is right.

Do more digging. You might just find the facts that say you are right.

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #128 on: March 22, 2014, 02:36:27 PM »
They defy the laws of physics. That's proof enough of a bug to report it. If you choose to believe in magic then that's your prerogative. If HTC choose to do nothing about it that's their prerogative. My job is done. Good night. :)
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Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #129 on: March 22, 2014, 02:40:14 PM »
Still you have no facts just assumptions guesses.  Keep in mind I also have zero facts to say the model is right.

Do more digging. You might just find the facts that say you are right.


Randy the descriptions and tests we're reading do not seem to match the game performance. Gscholz is correct, there is no noticeable drag and we have no explanation of why.

Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #130 on: March 22, 2014, 04:42:16 PM »
Randy the descriptions and tests we're reading do not seem to match the game performance. Gscholz is correct, there is no noticeable drag and we have no explanation of why.

He may very well be right.  I think we just need some old test data to offer to HTC .


Offline colmbo

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Re: P-38 dive flaps produce no drag
« Reply #131 on: March 22, 2014, 04:44:23 PM »
Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.


Randy you don't need to have something in writing to know something is amiss.  Common sense says the dive flap would produce some drag, that drag is going to slow the airplane…really no ifs, ands or buts about that.  The big unknown is "how much".

There are some speed brakes used on Mooney aircraft, small tabs that protrude from the wing skin when open.  At high speeds such as in a descent they are very effective, at lower speeds (such as approach to landing) they don't produce as much drag and have little effect on performance. (It's a physics thing, double the speed quadruple the drag IIRC)  IMO that is what we should be seeing from the dive recovery flaps on the aircraft in game.
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Offline colmbo

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Re: P-38 dive flaps produce no drag
« Reply #132 on: March 22, 2014, 04:46:56 PM »
If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.

You can't say that for sure.  They do produce a pitching moment which might be undesirable at times, other factors to consider regarding retraction other than just drag.
Columbo

"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

Fate whispers to the warrior "You cannot withstand the storm" and the warrior whispers back "I AM THE STORM"

Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #133 on: March 22, 2014, 04:55:54 PM »
If I remember right drag is relates to the square of the velocity in the subsonic range or laminar range.

I keep thinking that the dive flap,s noticeable drag occurs when the boundary layer breaks.  The design suggests to me, they wanted the boundary layer to only break at the same speed the top wing damned up.

Offline morfiend

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Re: P-38 dive flaps produce no drag
« Reply #134 on: March 22, 2014, 05:16:18 PM »
Meh I skim over these topics, and rarely ever go passed the second page. I just find that all topics seem to degrade into useless slander after that.

I really just wanted to say, "Be careful what you wish for"

...And slightly mad that the 109G10 was replaced with the less potent 109G14...

If I can't have my smoothed out engine cowl and an extra ~200HP, you can't have your P-38Ls. Settle with the J.


  Not to hijack this thread but we never had a G10 we had a K4 that was labled as a G10 so it could use the optional weapons,it had the performance of the K4. So we got the K4 and the G14 in exchange for the socalled G10.

  I miss the old G10 too but I glad HTC fixed that issue.



  Getting back to the P38L, IIRC widewing tested the dive flap and he found that you need to turn off combat trim and use manual trim to see the effects of the dive recovery flaps. I'm not sure of the difference as I havent flown the 38,let alone the 38L in quite a long time.


    :salute