Aces High Bulletin Board

General Forums => Aces High General Discussion => Topic started by: Widewing on August 26, 2007, 09:59:25 AM

Title: Quantifying B-25 Performance
Post by: Widewing on August 26, 2007, 09:59:25 AM
In keeping with my usual practice, I took the newest additions to the plane-set offline to quantify performance.

I did speed runs at MIL power and WEP at sea level (50 feet) and 5,000 feet.

I did max climb from sea level to 5,000 feet

I did minimum turn radius without flaps and with full flaps.

I also did max dive speed before failure, unloaded (no g applied to airframe).

All data was taken at 25% fuel at zero burn rate (about 28 minutes of gas in the MA) and no bombs.

Here's the data....

SPEED-

Sea level max speed, MIL power:
B-25C glass nose: 265 mph
B-25C solid nose: 264 mph
B-25H: 263 mph

Sea level max speed, WEP power:
B-25C glass nose: 277 mph
B-25C solid nose: 276 mph
B-25H: 274 mph

5,000 feet max speed, MIL power:
B-25C glass nose: 283 mph
B-25C solid nose: 282 mph
B-25H: 281 mph

5,000 feet max speed, WEP power:
B-25C glass nose: 293 mph
B-25C solid nose: 292 mph
B-25H: 291 mph

Max dive speed before structural failure (zero g loading): 450 mph
Max speed to induce structural failure at 4 g loading: 355 mph

Notes: Lighter weight means a slight increase in speed, but there is little to choose from as spread is typically just 3 mph from fastest to slowest. However, the B-25H has the slowest acceleration, typically taking 10 seconds longer from 200 to 250 mph. This is expected, because it is the heaviest of the three.

CLIMB-

Climb from sea level to 5,000 feet, beginning at 160 mph, using WEP power. Time in minutes:seconds.tenths of seconds to reach 5k.

B-25C glass nose: 2:04.70
B-25C solid nose: 2:13.59
B-25H: 2:29.81

TURN RADIUS-
B-25C glass nose not tested, but should be a bit better than B-25C solid nose.

Full flaps, three turns counter-clock wise, average time and speed. Three tests done, results averaged.

B-25C Solid nose: 705.7 feet @ 12.62 degrees/sec
B-25H: 772.1 feet @ 12.13 degrees/sec

No Flaps, B-25C solid nose tested: 837.0 feet @ 16.17 degrees/sec.

Max speed that allows you to begin lowering flaps is 185 mph IAS.

Note: Weight makes a big difference here. Considering the size of the aircraft, the turn radius is excellent. However, the turn rate is appallingly slow. Using flaps to maneuver with other aircraft, especially fighters is generally counter-productive. While you may gain an angle for a snap shot, you will find yourself hopelessly slow with little prospect of regaining E over the short term.

I suggest not using flaps while turning with other aircraft. Take note that the B-25C (solid nose) turns very well without flaps beginning from 260 mph. Be sure to trim manually, with elevator trim neutral (mid scale on the indicator). Starting at 260 mph, the B-25C can complete a 360 degree turn in 19.9 seconds, averaging just over 18 degrees a second. Since it bleeds E rapidly, the turn tightens dramatically. Clean and devoid of bombs, it turns tighter over one circle than a Fw 190D-9 or the A-8, and at a comparable rate of turn too. Of course, the B-25 bleeds E like crazy, and will not be able to sustain this much beyond a single circle, thus the 190s will quickly reverse the table on the Mitchell. Nonetheless, the B-25's excellent instantaneous turn rate and its tremendous gun package means that it is a major threat to many fighters during the first stages of a fight. You must make the first opportunity count as there is a strong possibility that there will not be a second chance, unless the enemy pilot is hopelessly inept (fortunately, there's plenty of those).

Speaking of manual trim, if attacking ground targets, be sure to trim at least neutral elevator to prevent augers. DO NOT load the aircraft beyond 4 g in the pull out. DO NOT trim so much up elevator that it induces more than 4 g. Reduce power to idle and attempt not to exceed 300 mph when diving on ground targets.

I forgot this myself and clipped a tree while carrying 2 fighter kills and 3 GV kills... Wasn't happy with my oversight.

My regards,

Widewing
Title: Quantifying B-25 Performance
Post by: beau32 on August 26, 2007, 10:19:26 AM
Very Informative. I just printed this out so I could study it a little more. And to do some praticing myself to compair notes.
Title: Quantifying B-25 Performance
Post by: Sweet2th on August 26, 2007, 11:04:48 AM
Awesome job WideWing as usual.I have one bit of info to add on it.

The bomb loadout i feel that works the best is the 3-1,000's.When and if you do get to the enemy field you only have so much time to drop the bombs so this loadout works really well.


The pilot is most vulnerable spot on the aircraft.The B-25-H takes hits very well and the modeling is top notch here.I got hit by a flak panzer last nite and instead of loosing  a whole wing like normal i had minimal damage.

(http://i229.photobucket.com/albums/ee262/BukkNasti/B25damage.jpg)



All in all the B-25-H is the most fun i have had in Aces High in a while.

If you could get 20 of these in a mission, with 20 people who know how to fly it, and some good fighter coverage, well lets just say reset points would come along alot easier.
Title: Re: Quantifying B-25 Performance
Post by: SunBat on August 26, 2007, 03:18:43 PM
Quote
Originally posted by Widewing

TURN RADIUS-
B-25C glass nose not tested, but should be a bit better than B-25C solid nose.

Full flaps, three turns counter-clock wise, average time and speed. Three tests done, results averaged.

B-25C Solid nose: 705.7 feet @ 12.62 degrees/sec
B-25H: 772.1 feet @ 12.13 degrees/sec

No Flaps, B-25C solid nose tested: 837.0 feet @ 16.17 degrees/sec.



Very interesting.  Thanks for the info...

Out of curiosity, how are you able to take the turn radius measurements above?  I'd like to know how you do that, if it's not too much trouble to explain.  

Thanks.
Title: Quantifying B-25 Performance
Post by: BiGBMAW on August 26, 2007, 04:14:28 PM
lobbing pumpkins at  m16s and flaks from 1.5k out..is..well..very nice


And I agree with the 4g and 350 compress...Ouch..done that a few times now..

Did ton think about trim neutral..thnx widewing
Title: Quantifying B-25 Performance
Post by: Krusty on August 26, 2007, 04:33:57 PM
Hum....

Shouldn't the -H be considerably slower? It's got a much blunter, draggier, nose (not to mention a huge foot-wide hole for the cannon barrel! lotsa drag there!)

I seem to recall reading the -C was the fastest variant (and to me 1mph is too close to count)


EDIT: P.S. I think the B-25s are too strong in this game. I came across some at 20k in a mossie. I unloaded hundreds of 20mm rounds (4x hispanos!) and wasn't even firing MGs after the first pass. Saw hitsprites EVERYWHERE (small clusters, each one should have brought down the plane).


In the end I gave up and parked off the tail at d400 and just unloaded into the lead. He soaked up well over 200 rounds directly into the lower arse before finally just going *poof* and leaving me with 1 eng dead, 1 PW, and no oil in the other eng.

I made it home with 1 wheel off the runway and no engine left to taxi, but it pissed me off. No way should the B-25 be THAT damned strong!
Title: Quantifying B-25 Performance
Post by: KTM520guy on August 26, 2007, 04:56:37 PM
I gave a B25 heck with a niki. It soaked up everything that I had to shoot with before the tail feel off.:huh
Title: Quantifying B-25 Performance
Post by: crockett on August 26, 2007, 05:02:58 PM
Thanks for the info.. you don't happen to have that info on other planes on a website somewhere do yea?
Title: Quantifying B-25 Performance
Post by: bj229r on August 26, 2007, 05:31:51 PM
i managed to plink b24's at 1.5k offline, if my stick wasnt so bad, might getem from 2k
Title: Quantifying B-25 Performance
Post by: Saxman on August 26, 2007, 09:49:21 PM
Krusty: And yet I took a single ping to the top turret from a P-38's Hispano and it killed my pilot.
Title: Quantifying B-25 Performance
Post by: Widewing on August 26, 2007, 11:09:55 PM
Quote
Originally posted by crockett
Thanks for the info.. you don't happen to have that info on other planes on a website somewhere do yea?


Try DokGonZo's website (http://www.gonzoville.com/ahcharts/index.php)

You'll need java enabled in your browser.

My regards,

Widewing
Title: Quantifying B-25 Performance
Post by: Krusty on August 27, 2007, 12:13:07 AM
I like that website for speed and climb charts, but wish he'd include bombers as well (Hey, I ain't complaining! I realize it takes a lot of work and he gets no thanks, but "if" I had a wish, it would be to include bombers)

[edit: typo]
Title: Quantifying B-25 Performance
Post by: BiGBMAW on August 27, 2007, 10:01:47 AM
all these "claims" of super B-25 armor NEED FILM...

Otherwise its just weenies  crying about the spilt milk
Title: Quantifying B-25 Performance
Post by: Krusty on August 27, 2007, 10:04:20 AM
bgbmaw, some folks are getting them, some are not. I wonder if it's not specific to the B-25, but a "rubber bullet" syndrome across the board? There's a post in the training forum (wrong forum methinks) about rubber bullets, and now I think they may be related.
Title: Quantifying B-25 Performance
Post by: Sweet2th on August 27, 2007, 10:10:24 AM
Quote
Originally posted by BiGBMAW
all these "claims" of super B-25 armor NEED FILM...

Otherwise its just weenies  crying about the spilt milk


FILM viewer is corrupted so it doesn't matter anyway.
Title: Quantifying B-25 Performance
Post by: Krusty on August 27, 2007, 10:12:34 AM
Good point
Title: Quantifying B-25 Performance
Post by: 68Wooley on August 27, 2007, 11:41:32 AM
This was posted on another thread, but its relevant here:

The B25 seems to have a generally strong airframe, but there are weak spots. I defended a B25 raid against a V-Base and killed 3 in an Osti. One went down to a single hit. The other two took multiple hits - 3 to 5 I'd guess. The one that went down to a single hit was probably a pilot kill. The other two I was aiming for the base of the wing as I normally do with buffs.
Title: Quantifying B-25 Performance
Post by: Shuffler on August 27, 2007, 12:24:45 PM
They seem to burn easier than a zeke...
Title: Quantifying B-25 Performance
Post by: Mak333 on August 27, 2007, 12:41:42 PM
Quote
Originally posted by BiGBMAW
lobbing pumpkins at  m16s and flaks from 1.5k out..is..well..very nice


And I agree with the 4g and 350 compress...Ouch..done that a few times now..

Did ton think about trim neutral..thnx widewing


I haven't tried this but... I noticed they are HE rounds, not Armor Piercing... does this still work against planes and vehicles?
Title: Quantifying B-25 Performance
Post by: Saxman on August 27, 2007, 01:07:49 PM
Light vehicles (Jeeps, M-3s, M-8s and M-16s) are toast long before they can even THINK of squeezing the trigger. Ostwinds have a better chance, but one well-placed shell from range has the potential of knocking out its turret at LEAST. The Ostwind MUST drop the Mitch outside of 1-1.5k, because any closer and she'll be waporized.

With proper approach angle and luck the cannon CAN destroy a tank. However you're more likely to just track them or disable the engine with HE.
Title: Quantifying B-25 Performance
Post by: Lusche on August 27, 2007, 01:13:15 PM
Quote
Originally posted by Mak333
I haven't tried this but... I noticed they are HE rounds, not Armor Piercing... does this still work against planes and vehicles?


Did a small practice run and got a 1 hit kill on tiger... :rolleyes:
Title: Quantifying B-25 Performance
Post by: Sweet2th on August 27, 2007, 01:14:02 PM
Quote
Originally posted by Saxman
Light vehicles (Jeeps, M-3s, M-8s and M-16s) are toast long before they can even THINK of squeezing the trigger. Ostwinds have a better chance, but one well-placed shell from range has the potential of knocking out its turret at LEAST. The Ostwind MUST drop the Mitch outside of 1-1.5k, because any closer and she'll be waporized.

With proper approach angle and luck the cannon CAN destroy a tank. However you're more likely to just track them or disable the engine with HE.


Point blank up too about 400 yards away the B-25's 75mm will kill an Osti in one shot.
Title: Quantifying B-25 Performance
Post by: BiGBMAW on August 28, 2007, 12:19:07 AM
just landed 10 kilsl in  the pumpkin lobber; ) weeeeeeee


7- m3s
1 spit 16
1-m8
1 t-34

fun


I really enjot the long range stuff..I always was a fan of mortars/artillery


Killeng the AAAs from 1.5-2k out is nice
Title: Quantifying B-25 Performance
Post by: Saxman on August 28, 2007, 08:43:59 AM
As I said, sweet, the Osti had better nail the 25H outside 1000yds, or he's ashes. ;)

I haven't knocked down any aircraft with the pumpkin chucker yet, but it sure is fun watching them evaporate under those 8 .50cal. :D
Title: Quantifying B-25 Performance
Post by: Dux on August 28, 2007, 09:30:48 AM
To repeat SunBat's question, I'd also like to know how you measure the distances for the turn radii...?
Title: Quantifying B-25 Performance
Post by: SuBWaYCH on August 28, 2007, 10:12:16 AM
I know im gonna get slapped around for posting this, but i have to share this.....
The whole trick to killing a tank in a B-25H with the 75mm is to come in on a panzrs,M4s,Tigrs arse and come within 200 feet of it. You have to shoot the 75mm right when you hit 200 feet from the target and then pull up hard. Thats how i kept killing rooks as a bish. :aok







:huh I was a bish :huh
Title: Turn Radius/Rate measurement & calculation
Post by: Optiker on August 28, 2007, 12:20:37 PM
Originally posted by Widewing:
**********************************
Testing for turn rate and radius is relatively simple in concept, but not so easy in practice. The aircraft must be flown with great precision right at the edge of the flight envelope. This takes some practice.

The method is as follows:

Set up a reference point to use as the beginning and end of each 360 degree turn. Most of us use the .target command set at some reasonable distance. I use 1,000 yards. Get into a turn, adding flaps as you need them. Engage WEP. You must maintain altitude, not letting the nose drop or wander up. You should have E6B enabled with the clipboard stowed.

When you are flying at the limit, time 3 full 360 degree turns. Check speed each turn. Average the 3 speed readings.

Let's say your average speed was 99 mph. Divide 99 by 60 to obtain Miles Per Minute, or 1.65. Multiply that by 5,280 feet, or 8,712 Feet Per Minute. Divide by 60 seconds, and get 145.2 Feet Per Second. Multiply 145.2 by the total time of the 3 turns. In this case, 54.84 seconds. This will produce 7,962.768 (total distance flown). Divide 7,962.768 by 3 to obtain the circumference of the average circle, or 2,654.256 feet. Divide this by Pi (3.14 will do) to obtain the diameter of the circle, or 845.304 feet. Divide by 2 to obtain the turn radius, or 422.65 feet for the F4U-1A

To calculate average turn rate, multiply 360x3/time, or 19.694 degrees/sec.

My regards,

Widewing

As WW states, getting consistent results is difficult. Requires flying on the edge of the stall without gaining or losing altitude. I believe Soda uses stall limiter and sets the angle as low as possible (.5 to 1.0 degrees), depending on plane.

Now, I'd like to know how instantaneous turn rate is measured -- how badboy generates the EM chart data???

Regards,
Optiker
Title: Quantifying B-25 Performance
Post by: SunBat on August 28, 2007, 01:37:58 PM
Thank you for posting that Optiker.  

That's an innovative way of of handling the problem.  I can see how it would take practice to get it right and to be consistent.  Nevertheless, if done the same way everytime (or close to the same) it is a handy way to check relative turn radii for different planes or for the same plane to learn the best turning techniques for that specific plane.  

I apologize for a minor hijack, but I was curious.    On with the B-25 discussion....