Author Topic: Escorts could only stay with bombers for 20-40 minutes?  (Read 15796 times)

Offline Vraciu

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #90 on: October 25, 2016, 08:45:18 PM »
Vraciu - did you ever verify the AAF Flight test cruise data for P-38F/G/H vs P-51A and B that I presented from Dean's 'America's 100 Thousand?

I did not.  Just finished recurrent and two long drives.  Haven't had time for anything serious as yet. 
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Offline ACE

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #91 on: October 26, 2016, 07:24:23 AM »
I'm not paying for anything that is flat.
Well what if she's got curves
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Offline drgondog

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #92 on: October 26, 2016, 10:07:07 AM »
Atwood did not quantify beyond simply stating "all the cooling drag" when other sources put it at 90% or less.

He also made no distinction between "cooling drag" and "radiator drag"......or whether he was referencing the drag of the ducting...........or whether he addressed the addition to the frontal area of the airplane.

It is his article that is parroted over and over across the entire internet whenever meredith effect is mentioned and I don't believe the article shows enough data points to be worthy of said parroting.

And while we're at it.............no, the racing P51s are not adding "boundary layer bumps" but rather reshaping the profile of the wing.

Two points and then a question.

First I disagree Atwood's comments and remarked that he must not know what his team wrote in the P-51D-5-NA Performance Calculations per NA-8449 in the Drag Discussion from page 19 through 26. You don't either because you missed the point that I quoted directly from the report and so noted them by reference and quotes.

Second point - I knew Bruce Boland and maintained contact with him over the years until he left us. If you recognize the name, you should stop and pause and ask yourself "Do I REALLY know what I am talking about" relative to the experiment of introducing a BL trip up front on the airfoil for improvement in the .67-.77M range? I won't say whether the practice is continuing.  As far as I know it was used on only one racing Mustang, but could have been more.

Question, repeated. What are Your academic and industry experience credentials - which you clearly think are far superior to mine that you feel comfortable making snide remarks about my background or 'belief' systems relative to Aerodynamics?

You cleverly avoided answering the question, you haven't demonstrated any real technical expertise to analyze Drag parameter to build performance estimates, and you casually threw off a vague comment about aero background. Blowhard or just a nasty cynic?

Nicholas Boileau "Honor is like an island, rugged and without shores; once we have left it, we can never return"

Offline drgondog

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #93 on: October 29, 2016, 07:43:13 AM »
I did not.  Just finished recurrent and two long drives.  Haven't had time for anything serious as yet.

Vraciu - To help narrow your focus, I would direct your attention to both the P-51D and P-38J Pilot Handbooks and go to the 10-15 page Flight Operations Charts for both.

Both Are documented from exhaustive flight tests for all the standard load outs, altitudes in 5K increments, Max Continuous Power (MP/RPM) settings and working down to best MP/RPM for maximum Combat range, also citing cruise speed in both Kts and Mph TAS.

These Flight Operations Charts are the source for all the published AAF tables, and particularly collected by Dean in his excellent "America's One Hundred Thousand".

 
Nicholas Boileau "Honor is like an island, rugged and without shores; once we have left it, we can never return"

Offline drgondog

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #94 on: October 29, 2016, 07:48:05 AM »
Icepac - My question to you to give me a brief summary of your Aerospace Engineering academic credentials and industrial experience has resulted in resounding silence.

The sound of Crickets in the background is deafening by contrast.
Nicholas Boileau "Honor is like an island, rugged and without shores; once we have left it, we can never return"

Offline icepac

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #95 on: October 29, 2016, 06:29:23 PM »
How about this.........

"you win the bragging rights".

My credentials don't need to exceed yours for you and I to realize that we are in partial agreement on some points and that I am not "wrong enough" for you to lodge a tick in the "w column".

As far as "missing points you made"............I simply didn't read them.

Maybe we could continue this at the AAFO forums where the guys who reprofiled the wings of strega, voodoo, dago red, and were involved with scoopless mustangs communicate on the internet.

You can post your stuff and we'll see how it is recieved.
« Last Edit: October 29, 2016, 08:13:37 PM by icepac »

Offline drgondog

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #96 on: October 30, 2016, 07:12:30 AM »
Peace brother - send me a link. I probably know some of them and I have a solid understanding of the changes stimulated by Pete Law, Bruce Boland and Lednicer.

As you know, reprofiling the wings are an important modification to squeeze the last iota of wing parasite drag, but the changes to thrust lines, mods to the lower cowl (both external and internal), canopy and other changes also helped.
Nicholas Boileau "Honor is like an island, rugged and without shores; once we have left it, we can never return"

Offline DaveBB

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #97 on: October 30, 2016, 08:47:02 AM »
What is the evaporative radiator that they installed in the wings of the racing Mustang?
Currently ignoring Vraciu as he is a whoopeeed retard.

Offline GScholz

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #98 on: October 30, 2016, 06:02:11 PM »
What is the evaporative radiator that they installed in the wings of the racing Mustang?

It's not a radiator. It is also known as a boil-off system. The coolant absorbs the heat through boiling/evaporation. The hot steam is then exhausted.

An interesting article on the subject: http://www.airspacemag.com/flight-today/how-reno-racers-keep-their-cool-16828199/?no-ist
« Last Edit: October 30, 2016, 06:18:21 PM by GScholz »
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Offline GScholz

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #99 on: October 30, 2016, 06:35:13 PM »
Rare Bear's evaporative cooling system in action.



In 1969 this system allowed Rare Bear to beat the Me 209's record from 1939. The Me 209 also used evaporative cooling.
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Offline MiloMorai

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #100 on: October 30, 2016, 06:48:22 PM »
As Rare Bear was powered by an air cooled radial engine, where was the water used?

Offline GScholz

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #101 on: October 30, 2016, 07:05:06 PM »
To cool the radial engine instead of air. Allowing it to go from this...



To this.



So they've basically converted it to a hybrid air/liquid cooling.
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Offline GScholz

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #102 on: October 30, 2016, 09:02:47 PM »
"With the first link, the chain is forged. The first speech censored, the first thought forbidden, the first freedom denied, chains us all irrevocably."

Offline DmonSlyr

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Re: Escorts could only stay with bombers for 20-40 minutes?
« Reply #103 on: October 30, 2016, 09:05:55 PM »
My dad had an RC Rare Bear. Was a cool plane and fast but the inevitable tail ripping off happened, and we lost it. Cool bird though.
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Offline MiloMorai

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