Author Topic: Strange P-40 stuff  (Read 2921 times)

Offline MiloMorai

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Strange P-40 stuff
« Reply #45 on: October 18, 2006, 06:36:09 PM »
Quote
They operated best between Sea Level & 15,000', around 350mph IAS, performance started badly falling off above this Alt., w/o the Supercharger that the Brass Hats had removed.
LOL, a new alternate history.:eek:

Maybe you should take another closer look at the Allison and RR engines used in the P-40.

Using this link the P-40 at 15000' doing 350mph is doing 450mphTAS.
http://www.csgnetwork.com/tasinfocalc.html

Isn't a/c speed data given in TAS?

Offline Col. Flashman

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« Reply #46 on: October 18, 2006, 06:56:40 PM »
HiTech

As I stated previously, from Discussions w/ Actual W.W. II Combat Pilots @ Air Shows, reading the Books they've Written, Reading the Interviews that they Gave to A.I.P. Reporters & other Newsman of the time, reading their Combat & De-briefing Reports.

Yes, I've read the Performance Spec Sheets for the P-40 & other W.W. II A/C that were assembled under controlled conditions while Test Pilots were wringing them out.

If W.W. II Combat Pilots are reporting the Air Speed they Saw, that was being Indicated on the A.S.I. @ a Specific point in time during a flight, how could it possibly be T.A.S., as the A.S.I. only gave I.A.S. read-outs?

Typical question.

Interviewer:
How fast were you going @ the time?

Typical Answer.

Combat Pilot:
When I glanced @ my A.S.I. the read-out was or the needle was pointing @ 250 or 275 or 300 or 325 or 350;

 Or whatever the Read-out @ that Specific point in time was when they were looking @ the Air Speed Indicator. Whether the A.S.I. was calibrated for American Standard or Metric or Knots. Yes, I'm deliberatly rounding off the numbers as more than likely they did themselves.

How can that possibly be T.A.S.?
Are they going to even think about looking @ a Conversion Chart to see before giving a Report or an Interview?
I don't believe so.

Unless you've flown in an actual Combat Situations, using the same A/C & Equipment they were issued & experiencing the same adrenalin rush that the W.W. II Combat Pilots had while an Enemy Pilot &/or Ground Forces were trying their hardest to Kill them, your current experiences w/ modern A/C & Equipment in None Combat Situations is hardly the same thing.

Though if you've Current Combat Pilot experience, you've an Idea of what the W.W. II Combat Pilots went through.
« Last Edit: October 18, 2006, 07:28:30 PM by Col. Flashman »

Offline Col. Flashman

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« Reply #47 on: October 18, 2006, 07:38:27 PM »
Quote
Originally posted by MiloMorai
LOL, a new alternate history.:eek:

Maybe you should take another closer look at the Allison and RR engines used in the P-40.

Using this link the P-40 at 15000' doing 350mph is doing 450mphTAS.
http://www.csgnetwork.com/tasinfocalc.html

Isn't a/c speed data given in TAS?


Always have to nasty & sarcastic don'tcha.

1st bit of actual usefull information you've give todate since I signed up.

Doesn't it all depend on the Particular A/C you're Flying, as each ones Performance is going to be different because of the many variables involved such as how it was put together @ the Plant, condition upon Delivery & then disassembled for shipment & then Re-assembled & Maintained & what tweeking the Crew Chief does to it to make it possibly perform better @ the Aerodrome?

For Performance Specs Sheet I believe.
But so far Not in the Combat Pilot Reports & De-briefings I've read, it's all been I.A.S. & I'm not stating that they All listed the around 350mph either., only some did.

Offline Reynolds

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« Reply #48 on: October 18, 2006, 07:54:13 PM »
Hey, under PERFECT conditions, could a P-40E come to a complete landing (full stop) inside of 100 yards?

Offline Debonair

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« Reply #49 on: October 18, 2006, 08:20:31 PM »
easily

Offline MiloMorai

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« Reply #50 on: October 18, 2006, 08:26:59 PM »
Well your 30 years of study didn't help you much with the Allisons, did it? :)  So, when it comes to you and your babbling Col, be sure. I am always suprised when some people don't think their anul excreations don't stink.

You ain't no angel when it comes to comments either.:eek: The comment to Knegel were uncalled for.
Quote
Laugh it up, Fussball.
So what P-40 data spec sheet gives a 450mph speed?

Btw, 270mphIAS is ~350mphTAS which is what the data sheet speed listed for most P-40s at 15kft. The only way a P-40 is doing 350IAS(450TAS) is going downhill.

Offline Debonair

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« Reply #51 on: October 18, 2006, 08:34:16 PM »
or if something clogs the static port at high alt

Offline Knegel

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« Reply #52 on: October 19, 2006, 12:02:19 AM »
Hi,

Quote
Originally posted by Col. Flashman


If W.W. II Combat Pilots are reporting the Air Speed they Saw, that was being Indicated on the A.S.I. @ a Specific point in time during a flight, how could it possibly be T.A.S., as the A.S.I. only gave I.A.S. read-outs?

Typical question.

Interviewer:
How fast were you going @ the time?

Typical Answer.

Combat Pilot:
When I glanced @ my A.S.I. the read-out was or the needle was pointing @ 250 or 275 or 300 or 325 or 350;

 Or whatever the Read-out @ that Specific point in time was when they were looking @ the Air Speed Indicator. Whether the A.S.I. was calibrated for American Standard or Metric or Knots. Yes, I'm deliberatly rounding off the numbers as more than likely they did themselves.


I think noone told something different!

Quote
Originally posted by Col. Flashman


How can that possibly be T.A.S.?
Are they going to even think about looking @ a Conversion Chart to see before giving a Report or an Interview?
I don't believe so.



A pilot could mix up IAS datas with TAS datas that got calculated afterward out of the IAS speed he saw in this particular situation.

If a P40 pilot told you that his plane had a normal speed of 350mph IAS between 0 and 15000ft, he made a mistake or he made a joke with you.

Or he told you that 350mph IAS was good possible between 0 and 15000ft, but he didnt mean Vmax level flight, but then i dont undertsand the 15000ft limitation.

There is no piston engined WWII plane i know that had a that constant IAS between 0 and 15000ft anyway! In general the Vmax IAS decrease with increasing altitude. Even the Spitfires with their Merlins, which are known to have a steep increasing power curve up to rated alt, show a decreasing Vmax IAS.


Greetings,

Offline gripen

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« Reply #53 on: October 19, 2006, 12:25:50 AM »
Quote
Originally posted by Badboy

At sea-level, standard-day atmospheric conditions (and for our purposes we can a just say sea level period, if Aces High models standard-day atmospheric conditions) all of these airspeed measurements will be equal, well except for IAS which is still dependant on those position errors, which are different for each aircraft type. An easy way to remember how their magnitudes relate to one another at higher altitudes is by using the square root symbol:



IAS and CAS are usually very close to one another. For most aircraft, usually within 10 to 20 knots or less. EAS is always less than CAS. For airspeeds of Mach 1.0 or less, the maximum difference will be 30 knots. TAS is always greater than all the other airspeeds, at altitudes above sea level.


It should be noted that in reality the conditions have quite large effect on these even at sealevel. Assuming standard conditions at sea level and also that the airspeed indicator is calibrated to these conditions, then:

CAS = EAS (and EAS = TAS as Badboy noted)

But if temperature is below normal conditions (the density altitude being the same), then:

CAS > EAS

If temperature is above normal conditions (the density altitude being the same), then:

CAS < EAS

Same way also density differences can cause large error despite the pressure altitude remains the same.

gripen

Offline paulieb

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« Reply #54 on: October 20, 2006, 04:24:51 PM »
So, say that I was a wealthy adventure seeker in WW2 who got his hands on a P-40 airframe and a RR Griffon engine, rated at 2200 HP (IIRC). Anybody wanna guess what that P-40's performance would be THEN?

I've always been curious as to whether the P-40's lack of speed could be solved by simply throwing more power at it.

Offline Reynolds

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« Reply #55 on: October 21, 2006, 12:18:16 AM »
Quote
Originally posted by paulieb
So, say that I was a wealthy adventure seeker in WW2 who got his hands on a P-40 airframe and a RR Griffon engine, rated at 2200 HP (IIRC). Anybody wanna guess what that P-40's performance would be THEN?

I've always been curious as to whether the P-40's lack of speed could be solved by simply throwing more power at it.


Good question. Next, change the .30s for 20mm...

Offline Col. Flashman

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« Reply #56 on: October 21, 2006, 12:35:32 AM »
Quote
Originally posted by MiloMorai
Well your 30 years of study didn't help you much with the Allisons, did it? :)  So, when it comes to you and your babbling Col, be sure. I am always suprised when some people don't think their anul excreations don't stink.

You ain't no angel when it comes to comments either.:eek: The comment to Knegel were uncalled for. So what P-40 data spec sheet gives a 450mph speed?

Btw, 270mphIAS is ~350mphTAS which is what the data sheet speed listed for most P-40s at 15kft. The only way a P-40 is doing 350IAS(450TAS) is going downhill.


The only thing I still keep seeing out of your posts is your continuous vomiting of what you perceive to be witty pithiness’ & caustic remarks w/ only a drop of usefull information.

He stated that it made him laugh, so I quoted Han Solo's comment to Chewbacca, " Laugh it up, Fussball". If you find dialog out of "Star Wars" being used here as Offencesive, then that's just pure Childishness on your part.

And as I keep stating, A.S.I.'s only give I.A.S. readings in those W.W. II A/C & if a Combat Pilot states that's what he saw that was being Indicated @ the Point in Time, who are you or I to say that he didn't see it, hmmmmm?
I'm NOT quoting Data Sheets & only a Marooone (a bugs bunny quote) would keep bringing it up when discussing statements from W.W. II Combat Pilot & their written reports.
And I'm not going to go digging through my collection to attempt to find them for you, as you've so far proven you've no interest in any thing different then what you believe can only be the truth as you perceive it.
It would be like trying to teach a Pig to Fly. It's a waste of time & it'll only annoy the Pig.
« Last Edit: October 21, 2006, 12:53:02 AM by Col. Flashman »

Offline hitech

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« Reply #57 on: October 21, 2006, 11:16:10 AM »
Quote
They operated best between Sea Level & 15,000', around 350mph IAS, performance started badly falling off above this Alt., w/o the Supercharger that the Brass Hats had removed.


Flashman: Is this a direct quote from somthing or are you interpitation other   quotes.

Beacuse let us say it is a direct quote, there is still nothing false about the quote.

Part 1.
They operated best between Sea Level & 15,000'
Do not belive anyone realy disputes that.

Part 2.
around 350mph IAS,

Still nothing inacurate, the 350 could be Vne or any thing else beside best level speed and once again could a true statement.


Part 3.
performance started badly falling off above this Alt.

Once again a perfectly true statement.

The real problem comes when you interpet that statement to meen it had a level speed  of 350 IAS at any alt. Because that number is so far from belivibilty , You would litterly have to renvent physics to ever have a plane with the HP and size of the P40 achieve that speed in level flight.


HiTech

Offline Angus

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« Reply #58 on: October 21, 2006, 12:05:22 PM »
Flashman....maybe the P40is your favourite plane...but:
Look at the P40, it's THICK wings, it's weight and power.
Where on earth can you get to the conclusion that it's a speedmonster?
P40 is rugged, packs a punch, and has a good rate of roll.
That's it though, - compare it to a Spit VIII which was operating in the med at the same time. Even a Spit V, not to mention a 109F or G, - once above some 15K the P40 is an UNDERDOG.  Fights were taking place up to 30K+, and the one that has the alt holds the cards. 15K is medium alt. A flock of 109F's at 22K will have a P40 for breakfast.
Even the humble Hurricane was used as an escort for P40's in the med, and I put my money on the reason being altitude performance.
Then ponder on this from HiTech:

"The real problem comes when you interpet that statement to meen it had a level speed of 350 IAS at any alt. Because that number is so far from belivibilty , You would litterly have to renvent physics to ever have a plane with the HP and size of the P40 achieve that speed in level flight."

Top speed is the highest achievable speed at level flight. Look at the AH charts to see that it is not a constant. Then realise the difference between IAS and TAS.

And as a final note, Milo knows his stuff. Don't remember errors from his shop, but be aware, he has a hot temper. Reading your text makes me understand his response.

Chao.
It was very interesting to carry out the flight trials at Rechlin with the Spitfire and the Hurricane. Both types are very simple to fly compared to our aircraft, and childishly easy to take-off and land. (Werner Mölders)

Offline MiloMorai

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« Reply #59 on: October 21, 2006, 02:59:17 PM »
Not hot tempered Angus, just have no patience for babbling nonsence.

He still has not acknowledged that the Allisons did have a supercharger. The Brass Hats removed the TURBOcharger from the P-39. He is a wee bit confused.

Graham White:

"With the exception of the B model, ALL V-1710s were supercharged by way of the engine-driven geared supercharger."

The B model was used in airships.