Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Widewing on June 09, 2004, 11:25:47 AM
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I decided to do some basic climb testing of a small sample of AH2 fighters.
My criteria was simple. First, I tried to balance fuel weight as much as is possible. Some aircraft would carry 25% total volume, others 50%.
Tesing was equally simple. Spawn on runway, auto-takeoff engaged (eliminating any pilot influence), start engine and go to max power (WEP engaged)
Standard of measurement: Time to 5,000 feet from wheels stopped.
Results:
Bf 109G-10 - 82 seconds (50% fuel)
La-7 - 84 seconds (50% fuel)
Spitfire Mk. XIV - 89 seconds (50 % fuel)
P-38L - 91 seconds (25% fuel)
P-47D-40 - 94 seconds (used my favorite 6 gun, 247 rds/gun config, 25% fuel)
F4U-4 - 95 seconds (25% fuel)
Fw 190D-9 - 97 seconds (50% fuel)
Interesting factors noted:
1) Both the P-47 and P-38 displayed sharp increases in climb rate as they passed 4,000 feet. Both easily exceeded 4k/min once above that altitude. Must be related to turbo efficiency.
2) The P-47 required more than twice the takeoff roll than the Bf 109 or La-7. This added 7-8 seconds to time-to-climb total. Once above 4k, the D-40 climbs at least as fast as the SpitXIV!
3) Initial acceleration is everything in this test. The first fighter airborne was the La-7. Once airborne (about 2 seconds after the La-7), the Bf 109G-10's better climb rate made up the difference rapidly. Passing 10k, the P-47D-40 appears to climb faster than the La-7, and the La-7's advantage decreases between 4k to 10k.
4) At 5,000 ft, all aircraft tested are climbing at a rate exceeding 4k/minute (the Dora only just barely).
5) Configured with 8 guns and full ammunition load, the P-47D-40 loses 300-400 fpm.
My regards,
Widewing
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interesting.
the P47 is not such a bad climber on wep. on wep is the key, since wep is very effective in the jug.
still, I find it hard to belive it climbed just as well as the f4u-4.
1) Both the P-47 and P-38 displayed sharp increases in climb rate as they passed 4,000 feet. Both easily exceeded 4k/min once above that altitude. Must be related to turbo efficiency.
strange. the jug (and I think the 38 too) have a very smooth power curve since it doesn't use a two speed charger like most planes. In other planes, there's a "jump" in power as the second stage kicks in.
Bozon
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Should the F4U-4 be that far down the list?
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widewing change your test procedure to the following. after reaching 800 agl, engage auto speed. Other wise you will be getting strage climb changes do to the auto take off controller trying to slowy get you to auto speed.
HiTech
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Hi Bozon,
>the jug (and I think the 38 too) have a very smooth power curve since it doesn't use a two speed charger like most planes. In other planes, there's a "jump" in power as the second stage kicks in.
Well, I think Widewing's observation is correct in that the P-47 (and probably the P-38, too) should have a greater climb rate at 4000 ft than at sea level due to turbo supercharger characterstics.
Deviating from US rating practice, turbo supercharged engines (with a mechanically driven supercharger "engine" stage like that of the P-47 and the P-38) didn't really give constant power from sea level to critical altitude, but apparently more of a parabolic curve which peaked relatively low and dropped very gradually towards critical altitude.
I haven't really understood the turbos yet, but Widewing's conclusion seems sensible to me :-)
Of course, a test from a standing start is difficult to do with perfect accuracy - optimally, one probably would have to climb up out of a deep hole in the ground at stabilized climb speed :-)
Regards,
Henning (HoHun)
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Hi folks, just got back here on the boards to DL AH2Beta.
Stumpled into Aircraft and Vehicles out of an old reflex.
I really wonder why the D9 is that "far" behind.
From everything i know the bird should be rated right behind the Spit XIV, especially with WEP.
But so long i think FM for AH2 is not 100% done yet, right?
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P47D40 14500lb 100% fuel, 12799lb 25% fuel, no more than 2450PS at 5000 feet.
190D9, 9414lb 100% fuel, 8992lb 50% fuel, 2100PS at 5000 feet.
We have a 0.19ps/lb P47D40 and a 0.23ps/lb 190D9 at 5000 feet, P47D40 should not be even close to the D9 in a substained climb to 5000 feet.
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According to http://www.hitechcreations.com/ahhelp/models/charts/190d9climb.gif
190D9 should be about 3000 feet per minute and 4000 fpm with WEP
P47-D40 should be just about 2500 fpm and 3250 fpm with WEP
http://www.hitechcreations.com/ahhelp/models/charts/p47d30climb.gif
Where I'm wrong ?
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Where I'm wrong ?
You're not wrong. The Jug was tested with 25% fuel and 6 guns, so that would have increased the climb rate. These tests would be more meaningful if full fuel was used.
ra
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Also he started otr and used auto take off...
The results are mostly meaningless.
I dunno why folks dont do the tests with full fuel...
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Originally posted by straffo
Where I'm wrong ?
Partially, these charts are from AH1 and 100% fuel loaded.
P47D40 100% fuel (2259 pounds of fuel) at sea level has power loading of 0.16ps/lb on wep
P47D40 25% fuel (565 pounds of fuel) at sea level has power loading of 0.19ps/lb on wep
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the net power that goes into climbing is P=m*g*R
where R is the rate of climb.
So for different loads:
R2/R1 = m1/m2 -> R2=m1/m2*R1
from HTC's help page:
P47D40 climb on wep with 100% fuel is 3250 fpm = R1
P47's weight with 100% fuel is 14400 lb = m1
P47's weight with 25% fuel is 11700 lb = m2
R2 = 4000 fpm.
Bozon
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I'm completly confused :confused: , why would the D9 climb slower at 50% than 100% ?
Something is wrong either in the chart or in the test.
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Say why not get the 109F in the test? It's quite a climber, that is, until the gas runs dry.
-Blogs
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Originally posted by straffo
I'm completly confused :confused: , why would the D9 climb slower at 50% than 100% ?
Something is wrong either in the chart or in the test.
Because of auto take off?
widewing change your test procedure to the following. after reaching 800 agl, engage auto speed. Other wise you will be getting strage climb changes do to the auto take off controller trying to slowy get you to auto speed.
HiTech
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You're right it more than probably that.
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Originally posted by Batz
Also he started otr and used auto take off...
The results are mostly meaningless.
I dunno why folks dont do the tests with full fuel...
I tested with low fuel because I rarely fly with more than 50% internal load. Why drag along useless weight? Load a drop tank, use it to get where the fight is.
Virtually all of the aircraft tested are used as interceptors, with the exception of the P-47 (and that may change once people are aware of its performance when light). Climbing ability from wheels stopped IS useful data if you intend to get up and defend.
My regards,
Widewing
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I think I heard AH2 will likely not allow you to takes less that 100% internal fuel and drop tank.
Also AH increases fel consumption multiplier a lot so 50% or 25% fuel wont last very long.
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Originally posted by GRUNHERZ
I think I heard AH2 will likely not allow you to takes less that 100% internal fuel and drop tank.
Also AH increases fel consumption multiplier a lot so 50% or 25% fuel wont last very long.
Unless they plan to change it after beta 41, this isn't the case. Besides, it was commonplace for fighters to be loaded with less than full tanks AND external tanks for exactly the same reason I do it.
I've been flying with less than full tanks in the beta for weeks. Fuel burn is 2.0, so it requires fuel management (IE reduced power settings) to transit to targets areas. The fuel models reward this with greatly increased range and/or endurance.
My regards,
Widewing
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Originally posted by hitech
widewing change your test procedure to the following. after reaching 800 agl, engage auto speed. Other wise you will be getting strage climb changes do to the auto take off controller trying to slowy get you to auto speed.
HiTech
HiTech,
Has this changed? I have done some comparisons on various aircraft using the method you mention above and leaving it on auto-takeoff all the way up. The results to 5k for both methods have been within 1 second of each other for the A6M2 (low powered plane), the Fw 190A-5 (mid powered plane) and the La-7 (hi powered plane).
In all cases, when auto-takeoff is left to itself, the plane climbs steadily and slowly reaches its climb speed. When I hit the auto speed at 800 agl, the plane dips to reach climb speed then resumes climbing. Like I said, each method got its plane to 5k within 1 second of the other method.
Did I just pick the wrong planes to check or did you change something? I'm getting ready to test all the planes and just want to be as accurate as possible.
Thanks!
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What are the numbers for 10k?