Aces High Bulletin Board

General Forums => Aces High General Discussion => Topic started by: Ack-Ack on July 01, 2005, 12:28:16 AM

Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Ack-Ack on July 01, 2005, 12:28:16 AM
P-38J
crew: 1
wingspan: 52' 0"
length: 37' 10"
height 12' 10"
wing area: 328 sq ft
powerplant: 2 x Allison V-1710-89/91 Vee-12 liquid-cooled engines
max speed: 420 mph at 26,500 ft
weight, empty: 12,780 lbs
weight, loaded: 17,500 lbs
weight, max: 21,600 lbs
service ceiling: 44,000 ft
armament: One 20mm cannon /w 150 r. four 0.50 cal mgs /w 500 rpg
# built: 2970


--------------------------------------------------------------------------------
P-38L/M*
crew: 1
wingspan: 52' 0"
length: 37' 10"
height 12' 10"
wing area: 328 sq ft
powerplant: 2 x Allison V-1710-111/113 Vee-12 liquid-cooled engines
max speed: 414 mph at 25,000 ft
weight, empty: 14,100 lbs
weight, max: 22,000 lbs
service ceiling: 44,000 ft
armament: One 20mm cannon /w 150 r. four 0.50 cal mgs /w 500 rpg
# built: 3923



Told you so.  And as you can see, it's the lighter weight of the J that gives it the marginal speed over the L, despite the newer and better Allisons the L had.  Now does this translate to an advantage for the J?  I guess in a level chase, the J would eventually catch up if both planes stay on a level plane.  Other than that, I can see no real advantage of 6mph.


ack-ack
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Wolf14 on July 01, 2005, 01:00:31 AM
would the 1500ft difference in alt make a 6mph difference in speed as well?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Schutt on July 01, 2005, 06:20:24 AM
In a lvl chase they would both be on the same lvl... the max speed of the J is at higher altitude though.

Also i heard the J had less drag due to the diffrent engine cowlings, is that true?

If so then i would guess most of the speed advantage comes from the reduced drag?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Wilbus on July 01, 2005, 07:15:42 AM
Which one has the highest deck speed?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: rod367th on July 01, 2005, 07:40:27 AM
p38 j    200ft  no wep   332mph   in ah2.......................... .p38l   200ft   no wep 333mph  ah2.






Both had 50% fuel
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Balsy on July 01, 2005, 07:55:06 AM
Weight has nothing to do with maximum speed. If you dont believe me, take any plane up with 100% fuel and then 25% fuel.

Balsy
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Keiler on July 01, 2005, 08:18:25 AM
That would be in Aces High 2?... which surprises me.
More weight means more drag due to higher AOA thus lower speed.
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Balsy on July 01, 2005, 08:28:05 AM
Im no aeronautical engineer but.. .in  level flight/maximum speed  isnt the AOA the same?

If I take a 727 up to 20K empty, will it fly faster at level flight than a full one?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: jon on July 01, 2005, 08:36:43 AM
i was just at the bong memorial in superior wisconsin(about 15 miles frome his home town of Poplar WI.)and the info there said that the 38L had a top speed of 414 and the 38J i cant remember the exact number but its top speed was around 385 (http://[IMG]http://img.photobucket.com/albums/v347/jongl/bong1657.jpg)[/IMG] (http://[IMG]http://img.photobucket.com/albums/v347/jongl/bong1648.jpg)[/IMG]
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: dtango on July 01, 2005, 09:50:45 AM
Keep in mind AOA / coefficient of lift is not only dependent on weight but also changes with the square of velocity.  Increasing velocity means reduced AOA.  

For max level speeds the change in AOA and resulting induced drag due to a change in weight are very small.  The impact on max level speeds would be imperceptible unless you're comparing speeds stabilized over a long duration.

For example a Beech Bonanza E33A with a max level speed of about 215 mph, the impact due to weight is about 1 mph per 100 lbs of weight.

Tango, XO
412th FS Braunco Mustangs
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: slimm50 on July 01, 2005, 09:52:50 AM
My only concern is, which one can I live the longest in?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Wilbus on July 01, 2005, 10:13:51 AM
Thanks Rod, could have done the test my self but was too lazy, appriciate it :)

Slimm, as for your only concern... the J I'd say.

Deck speed is the most important speed for any plane in AH. The J acording to Rod367th's test is only 1 mph slower at the deck compared to the L and it turns quite a bit better then the L.

The J is most likely the one you can live longest in. BUT it performs worse in high speeds and it doesn't have dive flaps.
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: slimm50 on July 01, 2005, 10:38:22 AM
Quote
Originally posted by Wilbus
...and it doesn't have dive flaps.

Heh, that's ok. I gave up long ago trying to get higher than everyone else. There was always someone higher than me. So I play below 4K agl, usually.
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: rod367th on July 01, 2005, 12:12:05 PM
25k  no wep  p38J    400mph        25k p38L   no wep 401 mph




what i found out is j climbs faster and can pull out vertical dive from 25 to 4k  hit x  and st8 and true flying  L model crashed same test.
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: eilif on July 01, 2005, 08:29:01 PM
Quote
i was just at the bong memorial in superior wisconsin(about 15 miles frome his home town of Poplar WI.)and the info there said that the 38L had a top speed of 414 and the 38J i cant remember the exact number but its top speed was around 385 [IMG]



alot of ppl seem to forget that each plane made in a series is different, depending on the mechanic, and how well he tuned it, how well each part was machined, rivet job, time of year, tempurature, ectra.

 the japanese planes had a wide area of performance because they were thrown together so fast and ran on such bad fuel.

i bet some day one of the ubber real sims will have a randomizer that will give each model of plane a unique tuning range.
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Furball on July 02, 2005, 03:24:23 AM
Quote
Originally posted by slimm50
My only concern is, which one can I live the longest in?


you should change your question to:

Quote
My only question is, which one can I kill the most in?
Title: To whoever asked me and didn't believe the P-38J is faster than the P-38L...
Post by: Squire on July 02, 2005, 09:23:55 PM
A 6 mph difference is statistically irrelevent. You could fly two identical models and one could be 6 mph faster than the other on any given day. 6 mph out of 420 mph is 1.4 percent.

They are published test speeds from somewhere, and just as easily the J was flown with a slighlty better engine that day, or a polished leading edge, or who knows what, maybe the bird crap on the nose wasnt polished off properly.

Any diff under 10 mph isnt even worth discussing really, despite the endless threads on plane X and plane Y.

My guess would be either a P-38J-25 or a P-38L-5 could do @ 410-420 mph tops in good shape, clean, with a pilot that made no mistakes.