Author Topic: Fighter-Bomber climb rates and time to target test results  (Read 1538 times)

Offline F4UDOA

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Fighter-Bomber climb rates and time to target test results
« Reply #15 on: October 03, 2003, 10:03:01 AM »
Karnak,

Did you check climb times to 10,000K with ord?

Offline Soda

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Fighter-Bomber climb rates and time to target test results
« Reply #16 on: October 03, 2003, 11:22:25 AM »
F4UDOA,
  "It seems" is a pretty vague testing method, how about some numbers to support your impressions from AH.  I believe Karnak was just trying to compare aircraft as modeled in AH so "historical documents" are inappropriate (thats a topic for another thread).

-Soda

Offline rshubert

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Special Request
« Reply #17 on: October 03, 2003, 12:42:25 PM »
Karnak, could you run that test with an A20G, 8X500, 25% fuel?  I would like to see how that bird compares.



shubie

Offline F4UDOA

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Fighter-Bomber climb rates and time to target test results
« Reply #18 on: October 03, 2003, 01:48:34 PM »
Soda,

Not exactly sure what you mean but here is a little more detail.

The Mossie's top speed at 10K in AH from the AH charts is approx 360MPH to 370MPH. Karnaks test show that with a full load of ordinance the top speed is 365MPH. That is NO loss of speed due to drag from ordinance.

By contrast

The F4U-1C top speed at 10K from the AH charts is 360MPH at mil power and 375MPH at WEP. With a full ordinance load the top speed is reduced to 320MPH at mil power. That is a fairly significant reduction in speed. Not the 50MPH I though earlier (I was looking at WEP) but still 30MPH which is significant enough.

I am not saying that the F4U speed should be higher, it's just that the Mossie shows no loss of speed (or minimal) regardless of loadout.

Climb looks the same.

Mossie max climb on the AH charts at WEP is approx. 2600FPM at sea level. With full ordinance and 50% fuel the climb is 3000FPM. Like I said are those bombs or helium ballons? How do you increase climb by adding ordinace??

By contrast

The F4U-1C has an initial climb of 3200FPM at WEP which is reduced to 2250FPM. That again is a significant reduction.

Do you think the Mossie should not loose any performance from adding ordinace? Am I wrong in my observation?

The Typ, 110 and Mossie all seem to have this anomoly.

Offline Furball

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Fighter-Bomber climb rates and time to target test results
« Reply #19 on: October 03, 2003, 02:13:19 PM »
one factor would be the mossie carrying ord in the bomb bay, which includes no drag penalty.  

Also the F4u is carrying more ord (BS american plane overloading) with a single engine compared to the 2 on the mossie.
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Offline Soda

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Fighter-Bomber climb rates and time to target test results
« Reply #20 on: October 03, 2003, 03:21:18 PM »
I had to dig a bit for these numbers into some of my tests but here goes:

Remember that the Mossie is only carrying 1K externally, the other 1K internally which only adds about 1mph of drag.  They do have drag, 10mph worth, 5mph/bomb, but the bombs are also smaller.  It's hard to compare that to something with two 1,000lb bombs hanging in the breeze, but anyway here are some other aircraft to consider that have the same 2K (all external @ sea-level) load carrying:

P-51D, 33mph penalty, 16.5mph/bomb
F4U-C, 25mph penalty, 12.5mph/bomb
Fw190D9, 12mph/bomb (can only carry 1 bomb, centerline, 500kg)
F6F-5, 20mph penalty, 10mph/bomb
P-47D30, 22mph penalty, 11mph/bomb
Typhoon, 17mph penalty, 8.5mph/bomb
P-38, 15mph penalty, 7.5mph/bomb

So, the P-51 is a little higher than most, it would appear the average is more about 10-12mph/bomb for 1,000lb type ordinance (or 500kg).    I threw in the Fw190D9 although it only has a single 500kg, but it added half the drag that two bombs would so it came out to the same mph penalty/bomb.  If anything, I think the Bf110G2 is a bit of an exception, I seem to remember the drag on the 1000kg option being rather low (more like 3-4mph/bomb) but I don't have those stats with me so I can't be too specific ( I think the mounting on those was different too, close together on centerline).

Move that to an abitrary 10K (as altitudes can favor one aircraft over another) and we get:

P-51D, 38mph penalty, 19mph/bomb (397->359)
Typhoon, 22mph penalty, 11mph/bomb (381 ->360)
P-47D30, 26mph penalty, 13 mph/bomb (362 -> 336)
Mossie, 11mph penalty, 5.5mph/bomb (367 -> 356)
F4U-1C, 28mph penalty, 14mph/bomb (354 -> 331)

Remember though, the Mossie is carrying two 500lbrs, not two 1,000lbs out in the breeze so you would expect there not be as much drag.  ALL the stats show a drag increase of about 2-3mph combined for both bombs, barely worth mentioning honestly.  The P-51D certainly suffers no more than a Typhoon at 10K, maybe slightly less.  Figure that to compare the Mossie fairly you'd have to double the numbers for it, so 22mph and 11mph/bomb, 2mph off the P-47, 3 off the Hog-C, and tied with the Typhoon.

On the climb issue, the C-Hog can maintain 2,500ft/min with 2K, right up through 10K (it varies less than 100ft/min throughout).  The P-51D starts slower (2,250ft/min) and surges a bit to (2,650ft/min) in the 5-9K range.  The Typhoon starts stronger (2550ft/min) but drops off steadily till 10K (2,000ft/min).  The Mossie is more like 3,100ft/min dropping to 2450ft/min by 10K.  That said, that's with only 1,000lbs of ord, not 2,000 (I only have 1 test that had only external ord, no internal) so I would expect those numbers to drop a bit with some extra weight.  The tests Karnak did include rockets too, those are real killers for performance, something like 1-2mph/rocket in most cases.  I didn't include rockets because that unfairly weights the tests a bit (although for Karnaks purpose it was entirely appropriate to include them).

So, looking at the numbers, I don't see anything really amiss.  The Typhoon pays a little less penalty for 1K bombs than the average (say 3-4mph total), but the P-38 pays even less.  The Mossie, well, it's hard to compare that as it's packing ordinance much differently.  It still follows the trend though of losing about the same amount/lb of external carriage, the fact that half the load is internal is an advantage (as you would imagine it should be).  Simple differences in bomb-placement on the airframe could account for these small differences.

-Soda

Offline Karnak

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Fighter-Bomber climb rates and time to target test results
« Reply #21 on: October 03, 2003, 03:22:59 PM »
F4UDOA,

I wouldn't see it that way.  Here are some factors to consider:

1: All twin engined aircraft handle ordinance better than single engined aircraft.  They are applying their power to the air more effectively and have more wing area.  In addition to that, half of the Mosquito's load is internal which removes the drag factor.

2: I was at 50% fuel for all tests.  The Mosquito carries 543 gallons and the F4U-1C carries 237 gallons.  Obviously the Mosquito gains more from 50% fuel than the F4U-1C does.

3: I was using the cockpit instruments to get my numbers.  The cockpit instruments in AH are not 100% accurate as they intentionally simulate WWII analog devices.  As Soda said, my Mosquito numbers are high as he found in his tests using the film viewer to get actuall speeds.  I didn't use the film viewer because it would have been more work than I wanted to do, the climb numbers would still have been analog and the speed numbers were, in my opinion, the least important data.

4: The climb numbers were read off of the cockpit guages and may be high due to instrument inaccuracies.  That said, the Mosquito is carrying less weight (some of it drag free) on bigger wings and has more power.

As you may have noted I still placed the F4U-1C above the Mosquito.

Yes, all tests are with the ordinance listed.  I did no tests with the aircraft clean.


rshubert,

Sure, I can do that.  Give me a bit.
« Last Edit: October 03, 2003, 03:30:01 PM by Karnak »
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Offline HoHun

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Fighter-Bomber climb rates and time to target test results
« Reply #22 on: October 03, 2003, 04:03:11 PM »
Hi Soda,

>Remember though, the Mossie is carrying two 500lbrs, not two 1,000lbs out in the breeze so you would expect there not be as much drag.  

Even if they were the same size, the Mosquito naturally would least affected by external bombs because it uses more power for the same speed than any of the single-engined aircraft.

As at any speed, the bombs can be expected to produce a constant absolute drag (in HP) for each aircraft, the Mosquito will lose the smallest percentage of its power because its absolute power is the highest.

On the opposite end of the scale is the P-51D that owes its high speed more to good aerodynamics than to power. That's why it's hit worst by the bomb drag.

Regards,

Henning (HoHun)

Offline Karnak

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Fighter-Bomber climb rates and time to target test results
« Reply #23 on: October 03, 2003, 04:20:21 PM »
rshubert,

Here ya go.

A-20G Havoc:
(eight 500lb bombs, 50% fuel)[/u]
Time to Target: 11:05
MIL Speed at 50ft: 297mph
MIL Speed at 10000ft: 314mph
MIL Climb: 2500ft: 1800fpm | 5000ft: 1550fpm | 7500ft: 1300fpm | 10000ft: 1250fpm
WEP Climb: 2500ft: 1850fpm | 5000ft: 1600fpm | 7500ft: 1450fpm | 10000ft: 1400fpm

Note 1: WEP expired at 7,700ft on continuous WEP climbout.
Note 2: Because I was only testing one aircraft I used the film viewer to get exact speeds for the A-20G.


The reason that I did not include the A-20G in the test is that it is not a Fighter-Bomber.  Air-to-air capability after dumping ordinance was included in my ranking considerations.
« Last Edit: October 03, 2003, 04:23:19 PM by Karnak »
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Offline rshubert

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Fighter-Bomber climb rates and time to target test results
« Reply #24 on: October 03, 2003, 04:21:05 PM »
Quote
Originally posted by HoHun
Hi Soda,

>Remember though, the Mossie is carrying two 500lbrs, not two 1,000lbs out in the breeze so you would expect there not be as much drag.  

Even if they were the same size, the Mosquito naturally would least affected by external bombs because it uses more power for the same speed than any of the single-engined aircraft.

As at any speed, the bombs can be expected to produce a constant absolute drag (in HP) for each aircraft, the Mosquito will lose the smallest percentage of its power because its absolute power is the highest.

On the opposite end of the scale is the P-51D that owes its high speed more to good aerodynamics than to power. That's why it's hit worst by the bomb drag.

Regards,

Henning (HoHun)


Oooh, excellent point about the P-51.  That makes a LOT of sense, even if we don't have the empirical data to look at.

Offline rshubert

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Thanks, Karnak.
« Reply #25 on: October 03, 2003, 04:23:37 PM »
And come on over some time, I will show you a few tricks in a light A-20 that might change your mind about air-to-air in it.



shubie

Offline Karnak

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Re: Thanks, Karnak.
« Reply #26 on: October 03, 2003, 04:29:06 PM »
Quote
Originally posted by rshubert
And come on over some time, I will show you a few tricks in a light A-20 that might change your mind about air-to-air in it.



shubie


Oh, I know that it can be successful in air-to-air combat in the right hands, but for the average player it is a deathtrap for air-to-air combat.

(I've taken B-26s {there were no A-20Gs in AH at that time} as fighters and killed F4U-1Cs)
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Offline HoHun

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Fighter-Bomber climb rates and time to target test results
« Reply #27 on: October 03, 2003, 06:01:20 PM »
Hi Rshubert,

>That makes a LOT of sense, even if we don't have the empirical data to look at.

Well, Soda's 10000 ft speed comparison is empirical data, and it confirms the theory :-)

Regards,

Henning (HoHun)

Offline Soda

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Fighter-Bomber climb rates and time to target test results
« Reply #28 on: October 03, 2003, 07:36:26 PM »
Good points HoHun, I also considered variations in bombrack dynamics and even position in relation to the aircraft structure (aerodynamic disruptions) can account for small differences.  I simply hoped my data indicated that there was no conspiricy theory at work and that a number of tested aircraft all showed similar performance in relation to similar loads. I think the numbers also showed the validity of Karnaks overall rankings in terms of performance.

I hope they fix the Mossie range though, the fuel load on it really is a harsh penalty.  I know HT said he's looking into it but I think if they made that change it would improve the Mossie into a very useful aircraft.  Right now it tends to be a bit too fringe in use.

Offline scJazz

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Fighter-Bomber climb rates and time to target test results
« Reply #29 on: October 04, 2003, 11:25:30 AM »
Excellent information Karnak! Thank you for the tests. What you have done is something I've wanted to do for awhile. I've been screwing around with gathering the effective gun damage potentials of aircraft in the recent past. No Soda not done yet. After spending 3 days home sick I'm now not home and don't plan to go back for awhile.

I think it will be neat to combine your test with my test and view performance information in combination with ordnance/gun damage potential.

The post with my info in it is over in the Analysis of Aircraft Guns thread in this Forum.