Author Topic: Sea Level acceleration testing (Read 2160 times)

Widewing · « **on:** December 05, 2006, 01:21:39 PM »

After the release of version 2.09, we discovered that some aircraft were demonstrating changes in acceleration from the previous version. It seemed that these changes were effecting acceleration above 300 mph TAS.

So, I elected to test several aircraft and compare the new data to that compiled and currently used on Dokgonzo's excellent interactive web page. Those numbers were accurate for the previous version of AH2.

My testing was done at 100 feet ASL. Only aircraft capable of attaining 350 mph at sea level were tested. This is not meant to be a comprehensive test, but to determine if there are changes and to what extent. Fuel was 25% with zero burn rate. Normal gun and ammo loads were used (no reduced ammo/guns).

Time was measured to accelerate from 150 mph TAS to 350 mph TAS.

Listed in order from fastest to slowest Second figure shows the difference from version 2.08 to version 2.09. If the difference between versions was less than 0.25 seconds, I considered it as no change.

Tempest: 1:00.38 No change
La-7: 1:06.75 +0.8 seconds (takes 0.8 seconds more to attain 350 mph)
F4U-4: 1:14.21 -2.8 seconds (takes 2.8 seconds less to attain 350 mph)
109K-4: 1:15.75 -0.8 seconds
190D-9: 1:17.21 -1.1 seconds
Typhoon: 1:25.78 No change
Spitfire14: 1:26.81 +1.3 seconds
La-5FN: 1:36.50 +1.8 seconds
F4U-1A: 1:37.17 New as of V2.09
P-51D: 1:38.31 -0.3 seconds
P-47N: 1:41.56 No Change
Ta 152H: 1:44.25 +0.9 seconds
Yak-9U: 1:47.37 +1.4 seconds
F4U-1D: 1:55.41 -22.5 seconds
F4U-1C: 2:00.25 -24.2 seconds
F4U-1: 2:01.61 -6.9 seconds
P-51B: 2:02.44 -3.7 seconds

You can see that most aircraft show minor changes or none at all. However, the F4Us all show improvement in acceleration, with the F4U-1C and -1D showing major gains. There was no previous version of the F4U-1A, but the newly added fighter displays very good acceleration over the whole speed range down on the deck.

My regards,

Widewing

Saxman · « **Reply #1 on:** December 05, 2006, 01:54:50 PM »

Any chance of getting a similar breakdown for low-end acceleration. Great to know the overall accel to max level at sea level, but low-end would be more useful to know for combat.

Gryffin · « **Reply #2 on:** December 05, 2006, 02:13:34 PM »

When you factor in that the F4U-1A has 50% more fuel than the F4U-1D (90 gals vs 60 gals) that is impressive.

But the question is "How is this possible?". I thought that empty, both planes were about the same weight but the -1D had a more powerful engine.

Or is the -1D faster to 200, 250, etc, and the -1A faster to 350 because of its higher top speed? (I'm at work or I would test this myself).

Reynolds · « **Reply #3 on:** December 05, 2006, 02:26:15 PM »

Is anyone else suspicious about the insane jump the -1C and -1D made?

Krusty · « **Reply #4 on:** December 05, 2006, 02:41:36 PM »

Yes. I think there are bugs yet to be worked out.

Charge · « **Reply #5 on:** December 05, 2006, 02:58:39 PM »

I thought 190A8 does 351mph at deck?

I does it with 1.65 ata so I don't know how much our A8 develops....

-C+

gripen · « **Reply #6 on:** December 05, 2006, 03:05:20 PM »

There was a discussion about strange shape of the F6F and F4U curves in the past. Perhaps the power output is fixed now?

gripen

Krusty · « **Reply #7 on:** December 05, 2006, 04:45:34 PM »

Charge, I don't think I've ever gotten a 190A8 in Aces High to 350 on the deck.

hitech · « **Reply #8 on:** December 05, 2006, 05:03:29 PM »

Widewing: I went and did your test in both 2.0803 and the current version.

Did the test on f4u1d.

V209 1:54
V208 1:55

I.E. both were in my margin of messering error.
So Im not sure where your error is comming from, but things have not changed.

Charge · « **Reply #9 on:** December 05, 2006, 05:41:11 PM »

"Charge, I don't think I've ever gotten a 190A8 in Aces High to 350 on the deck."

Well, then I'm glad the other planes fulfill the expectations.

-C+

moneyguy · « **Reply #10 on:** December 05, 2006, 05:55:42 PM »

Quote

Originally posted by Reynolds
Is anyone else suspicious about the insane jump the -1C and -1D made?

no

Widewing · « **Reply #11 on:** December 05, 2006, 06:28:16 PM »

Quote

Originally posted by hitech
Widewing: I went and did your test in both 2.0803 and the current version.

Did the test on f4u1d.

V209 1:54
V208 1:55

I.E. both were in my margin of messering error.
So Im not sure where your error is comming from, but things have not changed.

I used the data from DokGonzo's page for both the F4U-1C and the -1D. Also, Mosq tested the -1D immediately after V2.09 was released and posted his numbers in this thread.

His numbers for both software versions were:

F4U-1D
2.08: 150 to 350: 137 secs (2:17)
2.09: 150 to 350: 121 secs.(2:01)

I no longer have V2.08 to retest aircraft, so I used the data compiled by Mosq.

My test method is as follows:

Establish a steady speed of 140 mph. Add enough power to increase speed by 1 mph per second. At 150 mph, throttle goes to full power and WEP is engaged. Stop watch is started at same time. Worst case error is 0.2 seconds. Typical error is less than that. At 350 mph all aircraft are accelerating very slowly, and error on the back side is no more than 0.1 seconds. Since the error is consistent from plane to plane, 0.2 seconds is deducted from time on watch to account for reaction time.

Perhaps Mosq can elaborate on his test method. Maybe he carried more fuel?
Note that the differences between Mosq's V2.08 data and my V2.09 data are generally close, with no difference greater than 4 seconds, except for 3 of the F4Us.

My regards,

Widewing

hitech · « **Reply #12 on:** December 06, 2006, 09:14:57 AM »

Widewing:I assume you noticed your test and mine agree. Also I assume you used the E6B for speeds.

If you really want to validate that nothing has changed I can post a 20803 link for you.

HiTech

Krusty · « **Reply #13 on:** December 06, 2006, 11:21:32 AM »

In general, wouldn't one want to use full fuel to test acceleration? It would take longer, yes, but it would be more representative of how it would function in-game, right?

Widewing · « **Reply #14 on:** December 06, 2006, 06:10:57 PM »

Quote

Originally posted by hitech
Widewing:I assume you noticed your test and mine agree. Also I assume you used the E6B for speeds.

If you really want to validate that nothing has changed I can post a 20803 link for you.

HiTech

Yes, our times are with tenths of a second of each other. I'm a Project Engineer and I test a great deal of weapons hardware. Which, I suppose is why I test everything here as well, Not to validate per se, but to learn as much about each plane's flight envelope as is possible. For guys like me it's almost compulsive..

I appreciate your offer. However, I certainly believe what you say. I'm more curious as to how the 2:17 time was derived as it is vastly different from you times and mine. Perhaps Mosq will delve in and clear it up.

Thanks,

Widewing