Author Topic: P-38 dive flaps produce no drag  (Read 12097 times)

Offline nrshida

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Re: P-38 dive flaps produce no drag
« Reply #90 on: March 20, 2014, 09:46:09 AM »
You are referring to the haptic thread...

No, I'm eluding to the part where you asserted there was nothing wrong with Haptic Feedback as it was modeled (as it turned out, because you preferred it that way) hlbly demonstrated through independent research and consultation with an expert that it was incorrect, HTC corrected it, and then at a later date you used every logical fallacy and argumentative trap you could think of to try to humiliate him and save face.

Don't think you can re-image those sequence of events, troll boy.


Let us see anyone quantify the drag from the dive flaps. Since we lack the required test information it should be interesting. I'm sure tests were done and HTC may have a copy but we don't. The UK Air Ministry in 1953, after reviewing all the data on dive flaps available to them, concluded that it was impossible to predict the effect of dive flaps throughout the flight regime because there were too many variables interacting, only flight testing can give conclusive results. So far we have information that there was drag and there was a pitch up when deployed after compression. The first time I saw this discussed here was Feb 2002. I think HTC is aware of all the issues, including drag.

Zomg, now you really have gone full retard. You have absolutely no imagination or insight whatsoever do you. So no drag should be modeled because its behaviour could not be predicted without real world flight testing of an actual P-38 in every flight regime?

As accurate as HTC's flight simulation is it is still a model, an approximation, a representation. Do you really think they haven't been forced to use reasonable, educated assumptions and approximate calculations in other areas of flight modeling given the absence of actual specific flight test data?

This is absolutely no criticism of HTC by the way, if you're listening. I think their work is fantastic given the mostly non-flying antiques they are modeling, but are you really suggesting that the drag could not be reasonably calculated through an abstract model of some kind?


Congratulations FLS you win. Another excellent, reasonably investigated and presented issue discovered by a player of this game destroyed by your pedantic monkey business. Of course you have rather demonstrated what you're all about in order to do it haven't you? Good luck with the repairs to your future credibility.


Happy Friday Pipz!
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Offline nrshida

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Re: P-38 dive flaps produce no drag
« Reply #91 on: March 20, 2014, 09:50:36 AM »
Happy Friday Pipz!
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Offline BluBerry

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Re: P-38 dive flaps produce no drag
« Reply #92 on: March 20, 2014, 09:55:04 AM »

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #93 on: March 20, 2014, 10:44:59 AM »
No, I'm eluding to the part where you asserted there was nothing wrong with Haptic Feedback as it was modeled (as it turned out, because you preferred it that way) hlbly demonstrated through independent research and consultation with an expert that it was incorrect, HTC corrected it, and then at a later date you used every logical fallacy and argumentative trap you could think of to try to humiliate him and save face.

Don't think you can re-image those sequence of events, troll boy.


Zomg, now you really have gone full retard. You have absolutely no imagination or insight whatsoever do you. So no drag should be modeled because its behaviour could not be predicted without real world flight testing of an actual P-38 in every flight regime?

As accurate as HTC's flight simulation is it is still a model, an approximation, a representation. Do you really think they haven't been forced to use reasonable, educated assumptions and approximate calculations in other areas of flight modeling given the absence of actual specific flight test data?

This is absolutely no criticism of HTC by the way, if you're listening. I think their work is fantastic given the mostly non-flying antiques they are modeling, but are you really suggesting that the drag could not be reasonably calculated through an abstract model of some kind?


Congratulations FLS you win. Another excellent, reasonably investigated and presented issue discovered by a player of this game destroyed by your pedantic monkey business. Of course you have rather demonstrated what you're all about in order to do it haven't you? Good luck with the repairs to your future credibility.




It's amazing how much power I have. Every wish and bug report is at my mercy.  :lol

That was a quote from those "retards" in the Air Ministry. They had a bunch of older P-38s. Capt Eric Brown wrote about flying a borrowed F-5E specifically to test the dive flaps and aileron boosters. And their conclusion, looking at all the data available in 1953, was that modeling dive flaps was too complicated to get accurate results. Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up.

I have clearly stated that I believe there should be a pitch up and some drag. Somehow in your mind that puts me in opposition to the OP. You have been consistently wrong about everything. In the haptic thread you mentioned you also never got anything right. That's a large part of why I ignored everything you wrote. That and the rudeness. I won't rehash it here but anyone can read it and decide for themselves. Anyone with FFB can test an old version themselves. All the proof is available for anyone with the interest. No discussion neccesary.  :D
« Last Edit: March 20, 2014, 11:46:19 AM by FLS »

Offline nrshida

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Re: P-38 dive flaps produce no drag
« Reply #94 on: March 20, 2014, 12:02:15 PM »



It's amazing how much power I have. Every wish and bug report is at my mercy.  :lol

People would just rather go do something else than bother discussing with you. About as much point as talking to the wall.


looking at all the data available in 1953, was that modeling dive flaps was too complicated to get accurate results.

It's no longer 1953.


I have clearly stated that I believe there should be a pitch up and some drag. Somehow in your mind that puts me in opposition to the OP.

Completely missing the point I've been banging on about for about 3 pages. Willfully I should expect.


You have been consistently wrong about everything.

Yeah I've got rotten luck too. You'd think I'd get something right completely by chance.  :lol


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Offline Ack-Ack

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Re: P-38 dive flaps produce no drag
« Reply #95 on: March 20, 2014, 04:51:33 PM »
Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up.



Don't know about the dive flaps on the P-47 in game but on the P-38L, the dive flaps do provide a nose up pitch.  This was tested by both Widewing and myself a couple of years ago and posted our results.

ack-ack
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #96 on: March 20, 2014, 05:22:17 PM »
It's amazing how much power I have. Every wish and bug report is at my mercy.  :lol

. . . Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up. . .


You need to qualify the speed here.  In a dive, extra drag maybe modeled.  We have no way of testing.  Any flat level drag due to flaps may be modeled in but the change is so small, it is undetectable.  From all I have read, I see zero evidence the model is wrong or right.

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #97 on: March 20, 2014, 05:46:28 PM »
Don't know about the dive flaps on the P-47 in game but on the P-38L, the dive flaps do provide a nose up pitch.  This was tested by both Widewing and myself a couple of years ago and posted our results.

ack-ack
When I dive I find that the nose goes according to the trim setting. I can dive straight in to the ground or dive and pull out from pre-setting the trim. I don't find a difference between opening the dive flaps before I dive or after I'm buffeting. Opening after the buffet is supposed to pitch up enough to loop, 3-4g  just from the dive flaps. I don't doubt your results Ack-Ack but I don't recall the post and I don't know if we're looking for the same degree of pitch change. Link?

You need to qualify the speed here.  In a dive, extra drag maybe modeled.  We have no way of testing.  Any flat level drag due to flaps may be modeled in but the change is so small, it is undetectable.  From all I have read, I see zero evidence the model is wrong or right.

The info Cactus posted was advice to pilots. It's really hard to believe that they would be warned about a negligble amount of drag that is undetectable. It would be easier to believe that the extra drag was only prior to compression and it was reduced at compression because of the difference in the center of pressure but that's just spit balling. It seems likely that if all we needed was a fixed increase in the coefficient of drag  from the dive flaps we'd have that already.

« Last Edit: March 20, 2014, 05:49:15 PM by FLS »

Offline morfiend

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Re: P-38 dive flaps produce no drag
« Reply #98 on: March 20, 2014, 11:17:39 PM »
 Something I noticed in Ammo's pix is the fact that after the flaps were lowered the climb rate changed,now to be fair it was a small change from 1 fpm to 0 fpm but that does indicate a change in AoA so the flaps seem to be doing something.


  Of course that could be just bullpucky and the change is the reason the airspeed increased.




   :salute

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #99 on: March 21, 2014, 12:05:46 AM »
If you look at the map he's changed position noticably and we don't see the altitude on the 2nd shot.

I think the best thing to take away from ammo's pic is that the P-47 dive flap visual model is also extended 90 degrees instead of 21 degrees for the P-47. The amount of drag and pitch up should be clear to anyone testing it.  I don't notice any.

Offline lyric1

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Re: P-38 dive flaps produce no drag
« Reply #100 on: March 21, 2014, 03:28:17 AM »
Any one care to take the plunge & purchase this?

http://discovery.nationalarchives.gov.uk/SearchUI/Details?uri=C4020638

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #101 on: March 21, 2014, 05:23:21 AM »
We already have a few sources indicating a 3-4g pitch up when deployed at high speeds. Dive flap drag tests on the actual aircraft would be nice if we can find them. Since the intention was always to close the dive flaps as soon as they aren't needed it may be that drag tests for normal flight weren't considered important. 

At least the dive flaps we have work properly when we need them to. If you open them before the dive and close them as soon as they aren't needed you should have a well modeled "realistic" dive.

Offline lyric1

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Re: P-38 dive flaps produce no drag
« Reply #102 on: March 21, 2014, 12:49:45 PM »
Well the results might be in here 50 pages of Naca testing for a total of 16,457 documents . I won't be going through them all to find the one on the P-38. The first document alone is enough to make your head swim.

http://www.scribd.com/search-documents?escape=false&page=1&query=NACA+Ames+Aeronautical+Laboratory+Records+

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #103 on: March 21, 2014, 01:02:03 PM »
The P-47 uses essentially the same dive flap. Either one would be good. Flight testing for dive flap drag in service aircraft would be ideal.  :D


Offline lyric1

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Re: P-38 dive flaps produce no drag
« Reply #104 on: March 21, 2014, 01:08:57 PM »
The P-47 uses essentially the same dive flap. Either one would be good. Flight testing for dive flap drag in service aircraft would be ideal.  :D



P-51 do?

Don't have time to read it have to go to work.

http://www.scribd.com/doc/139117583/34811307-NACA-P-51X-Dive-Flap-Mods