Author Topic: P-38 dive flaps produce no drag  (Read 13915 times)

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #105 on: March 21, 2014, 01:34:11 PM »
That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere. 

Offline Ack-Ack

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Re: P-38 dive flaps produce no drag
« Reply #106 on: March 21, 2014, 04:24:41 PM »
That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere. 

This is the link for the report on the dive flap testing on a XP-51. 

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093004_1993093004.pdf

ack-ack
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Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #107 on: March 21, 2014, 04:39:51 PM »
Thanks Ack-Ack.  Still no drag or speed differences. They do state that the deployed flap pitch up is independent of the pitch trim with the flaps closed.
« Last Edit: March 21, 2014, 05:08:19 PM by FLS »

Offline Ack-Ack

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Re: P-38 dive flaps produce no drag
« Reply #108 on: March 21, 2014, 06:15:54 PM »
Here is a quote from gripen where he posts some drag numbers from a wind tunnel test.  Unfortunately, the links he provided are no longer valid but he does mention the serial number of the report with the drag data.

Ack-Ack and Murdr,
It would help a lot if you  actually understand what the report says:

"The outboard dive recovery flaps produced favorable shift in trim by decreasing the angle of attack for the zero lift and increasing downwash on the tail, but did not alter the the mach number the diving tendency developed"

Note the part on angle of attack (Ack-Ack) and part on diving tendency (Murdr), this can be confirmed from the graphs too.

For wind tunnel data on drag you should get that DSIR 23/15088. Here is some numbers from that report:

mach       clean        flaps
0,5        0,030        0,034
0,6        0,035        0,05
0,65       0,042        0,10


At mach 0,65 the dive recovery flaps doubled the drag.

gripen

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Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #109 on: March 21, 2014, 07:10:34 PM »
I assume that's wing drag not total drag so the increase in total drag at .5 Mach would be less than 13 % ?  In either case it seems drag should be noticeable. I'm guessing the lack of difference in top speed is due to the shock wave drag being so high.

Offline Les Paul

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Re: P-38 dive flaps produce no drag
« Reply #110 on: March 21, 2014, 10:10:43 PM »
Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and  since HiTech refuses to make a phony mock-up of the dive-flap system...

I vote that HiTech simply remove the P-38L from the game.

A wise man once told me, "Be careful what you wish for."
« Last Edit: March 21, 2014, 10:15:19 PM by Les Paul »

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #111 on: March 21, 2014, 10:36:52 PM »
Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and  since HiTech refuses to make a phony mock-up of the dive-flap system...

I vote that HiTech simply remove the P-38L from the game.

A wise man once told me, "Be careful what you wish for."


You may want to try reading a little slower.  :aok

Offline lyric1

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Re: P-38 dive flaps produce no drag
« Reply #112 on: March 21, 2014, 10:40:27 PM »
That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere. 

The link I posted before & the one AKAK has posted are one the same.
Scribd is free.

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #113 on: March 21, 2014, 10:46:13 PM »
Scribd  asks for payment  to DL the doc.

Offline lyric1

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Re: P-38 dive flaps produce no drag
« Reply #114 on: March 21, 2014, 10:47:58 PM »
Scribd  asks for payment  to DL the doc.

Really :headscratch: why can I access all that for nothing then?

Offline Les Paul

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Re: P-38 dive flaps produce no drag
« Reply #115 on: March 21, 2014, 10:59:57 PM »
You may want to try reading a little slower.  :aok

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.
« Last Edit: March 21, 2014, 11:08:15 PM by Les Paul »

Offline FLS

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Re: P-38 dive flaps produce no drag
« Reply #116 on: March 21, 2014, 11:40:01 PM »
Meh I skim over these topics, and rarely ever go passed the second page...

Good to know. Thanks for clearing that up.

Offline -ammo-

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Re: P-38 dive flaps produce no drag
« Reply #117 on: March 22, 2014, 01:10:56 AM »
Well Gscholz, thanks for identifying the issue. Good observation.  Sorry the thread was derailed into something more and unneeded.
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Offline Randy1

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Re: P-38 dive flaps produce no drag
« Reply #118 on: March 22, 2014, 11:09:17 AM »
Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and  since HiTech refuses to make a phony mock-up of the dive-flap system...

I vote that HiTech simply remove the P-38L from the game.

A wise man once told me, "Be careful what you wish for."


Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.

Offline GScholz

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Re: P-38 dive flaps produce no drag
« Reply #119 on: March 22, 2014, 01:25:56 PM »
Well Gscholz, thanks for identifying the issue. Good observation.  Sorry the thread was derailed into something more and unneeded.

Can't expect anything else on this BBS ;)
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