Author Topic: Spitfire 14 is porked (Read 3895 times)

Angus · « **Reply #45 on:** December 18, 2003, 07:04:38 PM »

Nashwan: you're spot on there.
I recall reading about the tests being made from a heated and running engin. Clock starts at opening up.
The Spit is nice there. Never saw a warbird taking off as easily as a Spit. If you count out biplanes, and,, ,, ehhh, Hurricanes actually.

Kweassa · « **Reply #46 on:** December 18, 2003, 09:04:53 PM »

Quote

Spit XIV, no wep, full load, with takeoff roll, 20K 6:46 Spit XIV, w. WEP, full load. with takeoff roll, 20K 5:50
in Real life this should be about 5 minutes, no WEP mentioned.
So the Spit XIV is definately porked. It actually gets outclimbed by the AH 109G2!
109G2 no WEP, full load,no gonds, with takeoff roll. 20K 6:34 109G2 w. WEP, full load,no gonds, with takeoff roll, 20K 5:48

So you're saying the guys who made this sim, lied when they posted the charts for their game, and your testings are absolutely right?

GScholz · « **Reply #47 on:** December 18, 2003, 09:28:10 PM »

Quote

Originally posted by Angus
Tested some climbers offline, just for fun....

Spit XIV, no wep, full load, with takeoff roll, 20K 6:46 Spit XIV, w. WEP, full load. with takeoff roll, 20K 5:50
in Real life this should be about 5 minutes, no WEP mentioned.
So the Spit XIV is definately porked. It actually gets outclimbed by the AH 109G2!
109G2 no WEP, full load,no gonds, with takeoff roll. 20K 6:34 109G2 w. WEP, full load,no gonds, with takeoff roll, 20K 5:48

Angus, Angus, Angus *shakes head* AH Spit14 on WEP is running 18lbs boost, 16lbs no WEP. The climb table at fourthfightergroup clearly stated 18.3lbs boost at SL and 18.3lbs boost where the SC could handle it. The test was done WITH "WEP".

GScholz · « **Reply #48 on:** December 18, 2003, 09:28:46 PM »

Fun being on this side of the argument for a change!

Hap · « **Reply #49 on:** December 19, 2003, 12:58:28 AM »

dunno what all the #'s are about; loadup a 14 with 303's and no bombs; take off, hit wep, level to end of run way hit alt-6, 4:53 later give or take a sec, you'll be at 20k. wep dies about 19k.

Angus · « **Reply #50 on:** December 19, 2003, 03:09:06 AM »

Kweassa: AH speed chart does not mention time to altitude, nor do HTC's webcharts give an absolute time to alt. The only things you can read out of the charts is climb rate at alt bands. So I checked it with a stopwatch. Guess what inspired me? Well, I had been flying the G-2 and found the climb rate quite impressive.

Oh, and Gscholz: the test I refer to is probably not the same as the one from fourthfightergroup. The only thing I can dig out about the engine is that it's an 18 boost engine, but whether it was applied in the test is not mentioned, however would be likely from the numbers.

None the less, sitting on the runway to 20K it is still almost a minute too slow, and slower than the G-2 (which may however be the case, would love to have recorded figures for the G-2)

GScholz · « **Reply #51 on:** December 19, 2003, 03:24:11 AM »

You're still wrong Angus. According to the climb table the Spit14 in the test reached 1700 feet in 0.35 minutes and 4000 feet in 0.8 minutes. The test was clearly not from "sitting on the runway", but rater already airborn, or at climbspeed rolling down the runway and timed from wheels-up.

http://www.fourthfightergroup.com/eagles/jf319.html

Angus · « **Reply #52 on:** December 19, 2003, 03:53:57 AM »

What Nashwan said:

"If you look at the A&AEE test of the Spit XIV, it's clear they either began the test staionary, or at wheels up, not at climb speed.

The table gives the time taken to reach 1,700 ft as 35 seconds, which equals a climb rate of just under 3,000ft/min. The plane was actually capable of over 5,100 ft/min.

If you assume a climb rate of 5,100 ft/min, 1,700 ft should take 20 seconds, which means 15 seconds wasted taking off/getting up to climb speed after takeoff."

Aha, see he has it wrong! 0,35 minutes is only 21 sec,has to be from liftoff. However, our AH spit only climbs to 1200 feet in that time. Awwww, this is getting frustrating

GScholz · « **Reply #53 on:** December 19, 2003, 04:13:10 AM »

I get a little over 1600 feet in 20 seconds when TO at climbspeed.

Angus · « **Reply #54 on:** December 19, 2003, 04:19:55 AM »

I started clocking at "gear up", still a few secs away from 170 mph
pewwie, gotta clock everything again.

GScholz · « **Reply #55 on:** December 19, 2003, 06:26:39 AM »

Ok so the bottom line is that you don't have any documentation to support your claims that the AH Spit14 is under modelled. You don't even have documentation that can justify the AH Spit14's current performance.

Nashwan · « **Reply #56 on:** December 19, 2003, 08:27:57 AM »

My mistake, it is .35 minutes instead of 35 seconds. In my defence, it was late, and I was tired

Angus · « **Reply #57 on:** December 19, 2003, 08:53:27 AM »

Well, GScholzie, got a present for you

Levelling after gear raise at roughly 175 mph, climb at 170 mph, I get to 1700 feet in 21 secs!!!
I roughly stay on the "line" of the fourthfightergroups figure all the way up to 20K. I am actually a couple of seconds faster than their figure, - but, alas, I did not set my fuel burn to the right figure, so I guess AH is totally spot on there.
It goes very much wrong after 20K though, the AH spit being lighter, but none the less a lot slower in the climb. It is a minute slower to 30K, and a whole 7 minutes slower to 40K
That would indicate that our XIV is porked actually

Well, it has the low alt performance of a high alt Spit XIV, and a high alt performance of a low alt Spit XIV. It gets outclimbed by a humble 109G2, and costs you perkies!!!!yeachhh
Anyway, honestly, nice to have help to get the test method right. Looking at it, the pilot would have to have done it this way, - he needs his arms for controls, he needs to write things down on his kneepad, a logical moment to start is by retracting UC, levelling to gain speed, start the stopwatch, and pull the stick!
Of course it would have been logical to start the stopwatch as one opened the throttle, but that's that.
So, my documentation DOES support the undermodelling of the Spit XIV, presumably at high alt, and to the best knowledge it is by far not performing properly in the turn. I hope that test pilot reports are good enough for that

Angus · « **Reply #58 on:** December 19, 2003, 08:54:49 AM »

Oh, BTW, how do you set fuel burn to Real Life value in the offline mode? And where can I get a good stopwatch for my desktop??

GScholz · « **Reply #59 on:** December 19, 2003, 09:31:46 AM »

Angus, did you reduce climb speed after 20K or did you just ride the autoclimb?

If you see the climb table at fourthfightergroup you will notice that as alt increases beyond 20K you need to reduce airspeed to get the best climb. Up to 20K you should have an IAS of 175mph, but at 30k it should be 151mph and at 40k 121mph, but there are many increments in between those alts. Also note that the test AC used 18.3lbs boost for longer than the 5-minute operational limit which is forced in AH.

I love being on this side of the argument for a change. I can see how much fun you guys must have had in the LW threads!