Spit 16

[Bronk]

Originally posted by dtango
1.98ata c3+mw50 best ROC: 4920 ft/min (3400 kg?)
1.8ata b4+mw50 best ROC:  4440 ft/min (3400 kg)
1.98ata c3 best ROC: 4320 ft/min (3400 kg?)

AH K4 best ROC:  ~4800 ft/min (3374 kg - assuming AH chart is normally loaded K4).

Assuming the weights are accurate the AH K4 best climb is nearest the 1.98ata c3+mw50 K4.

A correction to the speeds above, I didn't look at the speed diffs for the 1.8ata b4+mw50 version:
SL: ~595kph
alt: ~727kph

Level speeds the AH K4 seems nearest the 1.8ata b4+mw50 in the charts.  

Tango, XO
412th FS Braunco Mustangs

Lots to ponder on thanks tango.

Bronk

[Charge]

"More power means more maneuverability, not just speed. More power means doing literally everything better, including turn and burn flat turns on the deck."

Yes it should. Except for 190A8.

"One other thing I've noticed people referring to here that I thought I would clarify... weight of the aircraft has little impact on the max level speed of an aircraft."

Yes. Except for 190A8.

***
"With the falling fuel production that they would limit an aircraft to one specific fuel, when previously it could use either."

As was discussed earlier this is a question of how HTC wants to model a certain a/c. To what it was able to perform provided with certain optimal conditions or what it was historically able to perform in a certain timeframe.

That means that K4 was able to run on 1.98 ATA with C3 fuel (and correct spark plugs), but the fact (?) is that not much C3 was available when K4 was in squadron service.

***
How do you know that the compressibility was not taken into consideration in K4 performace charts? Is it the lack of such statement in the chart or is it specifically mentioned in those chart that it has not been corrected?

***
Do you people know if the intercooler problems which plaqued the P38 were fixed later on? As you know this reduces the power output so that the engine needs to derated to lower boosts to prevent the engine from detonation.

-C+

"Don't even get me started on Kurfurst. I have only one word to say about that individual - serial liar."

Take your "Kurfy bashing" to a board where he can answer you if you are up to it, please. Besides your history on these boards has been so brief that you hardly can state such things about people you hardly know. Of course you are just using it to get acceptance in certain crowds...

[Benny Moore]

Originally posted by Charge
Yes it should. Except for 190A8.

That is illogical.  The FW-190A-8 has far more weight than the FW-190A-5.  That is what makes the A-8 worse, not the power.  If only the power were raised and not the weight (as is the case when raising the engine's power rating), it would do everything better, with the aforementioned exceptions of sustained diving at full throttle and instantaneous turn in a certain direction.  It would go faster, climb better, accelerate faster, and turn better.

Originally posted by Charge
Do you people know if the intercooler problems which plaqued the P38 were fixed later on? As you know this reduces the power output so that the engine needs to derated to lower boosts to prevent the engine from detonation.

Yes, they were fixed in the P-38J.  In fact, it went from having inefficient cooling to having too efficient cooling.  Underheating became a problem at very high altitudes.  Moreover, with 150 grade fuel, running at high manifold pressures (75") was recommended for a minimum of fifteen minutes every flight, regardless of whether or not you needed it.  Apparently, it prevented spark plug fouling or something.

Originally posted by Charge
your history on these boards has been so brief that you hardly can state such things about people you hardly know. Of course you are just using it to get acceptance in certain crowds...

I was Aerial Target in the linked thread.  I knew Kurfurst quite well.  Big Kahuna (whom Kurfurst repeatedly falsely accused of lying to Oleg Maddox and fabricating data) was the flier who taught me many of the P-38 tricks I know.  As for giving him a "fair fight," I hardly feel that's necessary.  I am not at all slandering him as he was others.  A quick look through a few threads should make that fairly obvious.  If you like, I can provide a list of outright lies of his which, unprovoked, attacked honest individuals.  And then their are outright lies that did not attack anyone, such as his admitting that the Me-109 in Pacific Fighters was overmodelled in climb and later saying that he never said it.

[Charge]

"That is illogical. The FW-190A-8 has far more weight than the FW-190A-5. "

Depends on the relative change between the two factors. Strange enough the pilots alledgedly considered the A8 to be the best fighter of FW190A breed.

And the weight does affect its top speed. Although the difference to the mentioned P-51D maybe different because of the wing profile used in these two planes. Maybe the laminar flow wing is less sensitive to profile incidence angle change because of the weight increase.

"Moreover, with 150 grade fuel, running at high manifold pressures (75") was recommended for a minimum of fifteen minutes every flight, regardless of whether or not you needed it."

From MWs docs:

"a.  It is recommended that the Allison V1710-89 and 91 engines be rated at 70.0" Hg. when using 44-1 fuel or its equivalent. Because of the mechanical and maintenance characteristics of the engine and the P-38J installation this rating should be limited to a very short time. Periods between overhaul should be shortened for the engines using this power."

The expression of "short time" is strange. But in all considering the shortened service life before overhaul I find your statement a bit strange. Although it is possible that the engine requires a high pressure run to to keep clean, but 15 minutes? Maybe the restriction was loosened later on?

Im through with Kurfy topic. Not saying he's a saint but not worse than some other people in the other camp, but when he was in these boards back then there where quite heated discussions making not much sense in topic wise.

-C+

[dtango]

Charge: RE: compressibility correction...

On the first page of the Mtt K4 document there's a section in German called "macheinfluss:" (mach influence).  On Kurfurst's site they have it translated as:

"Mach effects : Not taken into account in the calculation.
                       Greatest deviation at the Volldruckhöhe with Sondernotleistung, ~5 km/h."

Tango, XO
412th FS Braunco Mustangs

[dtango]

Don't have to the time to post info to make it clear but weight has little impact on the max level speed of an aircraft.  At high airspeeds profile drag dominates and is the primary factor in determining power-required (drag) for the aircraft.

Tango, XO
412th FS Braunco Mustangs

[Knegel]

Hi dtango,

why do you post the 109K4 datas with the DB605DC, but not the one with DB605DB + MW50??

Actually the 109K4 data sheet with the DB605DB show a better performence than the DB605DC without MW50!!!!!

Datas from the 109K4 DB605DB/ASB sheet:

Vmax sea level: 595km/h!! Like in AH
Vmax 7000m : 725km/h!!  20km/h faster in AH
Best climb : 4400ft/min



Regarding the compressibility:

As we can see on the picture you posted, there are almost no compressibility influences up to 600km/h at sea level(thats less than mach 0,5 at 20°C), thats what i wrote.


Regarding the P51 weight  and K4 speed:

Nowhwere you can read that i wrote the 109K is to slow or to bad in AH, its rather the other way around, some say its to good!!!

The P51D and B in AH fly as fast as the K4 with 100% fuel at SEA LEVEL!!

I took this altitude to compare the speeds, only to minimize the influences by the compressibility(always difficult to estimate) and to show that the 109 with its weight, size and power already must have had a bad propeller etc to be that slow, or the other way around, the La7 and specialy the P51´s must have been better regarding this.

The high altitude speed of the K4 simply seems to be to fast, but since the plane reach the Vmax at 7000-7200m it cant be the DB605DC!!!!

With the DB605DC + MW50 the K4 had its Vmax already in 6000m!!

So if the K4 is to fast in high alt, its something for the bug forum, but nothing to assume the K4 have the 1.98ata engine.

The climb from 200ft + 1min gave me 4500-4600ft/min climb, thats a bit to good, but not realy far off.

Where do you got 4800ft/min from???

btw, in one of my former posts i mixed up the DB605Dc climb(5000ft/min) with the DB605DB climb.

Greetings,

Knegel

[dtango]

Knegel:

I assumed the B4+MW50 was going to be slower.  I looked at the chart and realized that according to the chart that was a wrong assumption, so I posted the correction above in my response about the climb rates.  It's up there.  I wasn't trying to selectively hide stuff .

Regarding 725km/h.  ~725km/h (450 mph) is roughly what the AH K4 is at altitude.  Take a look at the AH speed chart.  It's above 450 mph.

Regarding compressibility - yes at sea level ~595km/h we get mach .48.  But at alt (21k ft) the 725km/h is mach .64.  I was referring to the Mtt report and the quoted speeds there, not your AH tests.  My apologies if that was confusing.  If they aren't factoring compressibility ("mach influence" in the report) then speed listed in the Mtt report at altitude is higher than it would be.

The 4800 ft/min best ROC is from the AH climb chart on their webpage.

Tango, XO
412th FS Braunco Mustangs

[Krusty]

Originally posted by dtango
1.98ata c3+mw50 best ROC: 4920 ft/min (3400 kg?)
1.8ata b4+mw50 best ROC:  4440 ft/min (3400 kg)
1.98ata c3 best ROC: 4320 ft/min (3400 kg?)

Really, huh? What alt?

Because even the 109G-14 almost pushes 5000fpm climb, and it's nowhere NEAR 1.98ata. G-14 climb rate is actually BETTER than that of the K-4 between 3k and 10k. Only by a small margin, but this is a draggier airframe with less power climbing better. And it's a heavier frame, too! 7700lbs vs K-4's 7440lbs.

You can't use climb rate to determine boost. That much I'm sure of.

[dtango]

Krusty: Look at the highest peaks on the Mtt charts in the climb reports for the K4.  Those are climb rates for a particular boost + fuel + mw50.  I'm just quoting those.

Tango, XO
412th FS Braunco Mustangs

[Krusty]

http://www.gonzoville.com/ahcharts/index.php?p1=109k4&p2=109g14

^-- what we've got in-game right now. Climb alone doesn't dictate or reflect boost levels used. Unless you're saying the G-14 has 1.98ata, too??


Edit: I'm not picking a fight. I'm just pointing out the climb isn't part of the equation. Too many variables to simply pin it on boost alone.

[Bronk]

Originally posted by Krusty



Edit: I'm not picking a fight. I'm just pointing out the climb isn't part of the equation. Too many variables to simply pin it on boost alone.

He didn't check his previous posts on speeds at alt.

Bronk

[Ball]

why does every thread about the Spitfire turn into 109 rants?

[Guppy35]

Originally posted by Ball
why does every thread about the Spitfire turn into 109 rants?

Because the Spitfire apparently always does too much and the 109 always does too little in a flight sim.....regardless as to whether it's true or not

[Kev367th]

Originally posted by Guppy35
Because the Spitfire apparently always does too much and the 109 always does too little in a flight sim.....regardless as to whether it's true or not

Lol

Also usually wanting the LW birds at the max boost they ever flew at, while restricting the Spits to the min boost they flew at.

Still have the whines about the old Spit Vc ringing in my ears, just imagine a 14 @21lbs and a 16@25lbs.
As they allow LF IXe skins on the XVI it's clear they consider them (rightly) the same aircraft, you could have a 25lbs LF IXe from May 1944 .

[edit] To be fair it only appleis to a small minority. They usaully require more and a higher standard of proof for Spit boost levels than what they are prepared to give for the LW birds.