P38J at alt

[CAP1]

hey guys.....not sure if i should put this here or in general discussion?


last night, i was in mw......having issues with my back, so i launched, hit auto climb, and went afk.

 came back, and i'm passing through 22k, so i went level. looked at the map, and see a LOT of cons and a single friendly near V38. i call him on squad vox, asking if he has vis on em. he did....he was a little below 20k, and called them all out as being above him. i found them. there was a gaggle of 109(F's i think) all around 20 to 22k.
 i climbed a bit more to just over 23k, let my speed come back up, and went in on them....sort of. i would pick one of the higher ones, and try to make a pass.

 the problem i was having though, was that i would get my stall buzzer, and the shudder of the oncoming stall with even just a gentle pull out. i was chopping throttle when i'd go in. on one pass, there was one i'd guestimate to have been about 20k, that looked like he was focused on a squaddie. i tried to pick him, and cut to 1/2 throttle as i dove for him. i then felt the shudder of compression,(well before i got near him) went to idle, full up trim, full right rudder, everything i could think of to prevent the compression i entered. went into it anyway, and couldn't recover till about 16k.

 so.....my questions?  how does one fight in the 38 at that alt? how does one fight against a 109 in a 38 at that alt? how does one prevent compression at that alt?

 i'm rarely up that high, and wouldn't have been had i not been afk for so long.

 and, yes, we all did try to drag em down lower, but i never heard any reports of any of them getting lower than 20k alt.

 i just couldn't believe that i had so much trouble performing a seemingly simple turn at those altitudes.


thanks!

[ACE]

All 109's should be able to outturn a p38...but if the 38 stick is good its a differnt story

[bongaroo]

All 109's should be able to outturn a p38...but if the 38 stick is good its a differnt story

Wow, you really did a bang up job of answering his question....

[TonyJoey]

Wow, you really did a bang up job of answering his question....

Same with you.

At alt in almost any plane simple maneuvers can be difficult because of the differences in true air speed and indicated/ground speed. This might be incorrect, but I've always thought of it this way-The plane flies like it would at the indicated speed, but is actually going the true air speed. e.g  A P-38J is at 30k and has a indicated/ground speed of 175, while it has a true speed of 300. The plane flies as if it we're going 175, but is actually going 300. Just my intrpreation of it.

[CAP1]

All 109's should be able to outturn a p38...but if the 38 stick is good its a differnt story

that wasn't the question..........and i don't feel as if i qualify as a "good" 38 pile-it........yet.

the question was......well....just go re-read the post, and you'll see.

[CAP1]

Same with you.

At alt in almost any plane simple maneuvers can be difficult because of the differences in true air speed and indicated/ground speed. This might be incorrect, but I've always thought of it this way-The plane flies like it would at the indicated speed, but is actually going the true air speed. e.g  A P-38J is at 30k and has a indicated/ground speed of 175, while it has a true speed of 300. The plane flies as if it we're going 175, but is actually going 300. Just my intrpreation of it.

hhmm......this actually causes a little more confusion now......because it means that technically, i can compress at 200 or so, rather than over 400? but yet, it would easily explain the stall warning on gentle turns too........

[BaldEagl]

A lot different fighting at high alts vs. low alts hey?

The problem you run into at higher alts is that your IAS is a lot lower relative to your TGS than at lower alts.  As an extreme example there was a little challange on the boards not long ago as to how high you could get a 163.  The record was somewhere around 94K so I thought I'd give breaking it a try.  I can't remember the specific alt but somewhere around 80K my 163 was both shuddering from flying too fast (Well over 500 mph TGS) and the stall buzzer was sounding because I was going too slow (Under 100 mph IAS).  I was attempting to manage that phenomenon when, as I broke 90K my plane dissapeared (evidently a game limitation as it also happened to others).

So, what does all this mean to you and you're P-38 at 20K?

You're already starting with more speed (TGS) and less airflow (IAS) than you would be at a more moderate alt.  Therefore it's much easier to compress as you don't have to gain much more speed to do so.  Compounding compression (or control stiffness) at higher alts is that the air is thinner and there's less air for the controls to work against to rectify any problems.  Again I'll go back to a 163 example.  One day I chased a P-51 up to almost 60K when my 163 experienced mach tuck and went into a spin.  While I was doing everything I could to get it back under control I wasn't able to do so until I was under 10K.  There simply wasn't enough air for my control surfaces to work at the speeds I had attained.

On the other side of the coin you are flying with less airflow over your wings (IAS), even though you're going faster relative to the ground.  This airflow is what's required to fly and as it decreases you get the stall buzzer.  At higher alts each of your moves has to be longer and more deliberate than at lower alts so as not to disrupt the already minimal airflow you have moving over your control surfaces (i.e. you have to better control your control surfaces angle of attack).  A move that would work well at low alts will cause a stall or a spin at higher alts so you need to move more gently and deliberately.

In my experience the P-38 is a very strong high alt fighter and despite what the other poster said it should be able to prevail against most 109's at those types of alts where none of the 109's or 190's are really in their element.

Hope that helps.

[Soulyss]

Looks like most the other folks answered the question, flying at altitude is completely different than the typical MA fights.  There are a couple fields in the TA at I think about 20k alt.  If you see me online and you want to play around at 20k+ let me know and we can head over there and stooge around and see if we can keep the birds from falling out of the sky (I think the last time I was up that high was for the DSG scenario so I could use the practice too). 

[CAP1]

A lot different fighting at high alts vs. low alts hey?

The problem you run into at higher alts is that your IAS is a lot lower relative to your TGS than at lower alts.  As an extreme example there was a little challange on the boards not long ago as to how high you could get a 163.  The record was somewhere around 94K so I thought I'd give breaking it a try.  I can't remember the specific alt but somewhere around 80K my 163 was both shuddering from flying too fast (Well over 500 mph TGS) and the stall buzzer was sounding because I was going too slow (Under 100 mph IAS).  I was attempting to manage that phenomenon when, as I broke 90K my plane dissapeared (evidently a game limitation as it also happened to others).

So, what does all this mean to you and you're P-38 at 20K?

You're already starting with more speed (TGS) and less airflow (IAS) than you would be at a more moderate alt.  Therefore it's much easier to compress as you don't have to gain much more speed to do so.  Compounding compression (or control stiffness) at higher alts is that the air is thinner and there's less air for the controls to work against to rectify any problems.  Again I'll go back to a 163 example.  One day I chased a P-51 up to almost 60K when my 163 experienced mach tuck and went into a spin.  While I was doing everything I could to get it back under control I wasn't able to do so until I was under 10K.  There simply wasn't enough air for my control surfaces to work at the speeds I had attained.

On the other side of the coin you are flying with less airflow over your wings (IAS), even though you're going faster relative to the ground.  This airflow is what's required to fly and as it decreases you get the stall buzzer.  At higher alts each of your moves has to be longer and more deliberate than at lower alts so as not to disrupt the already minimal airflow you have moving over your control surfaces (i.e. you have to better control your control surfaces angle of attack).  A move that would work well at low alts will cause a stall or a spin at higher alts so you need to move more gently and deliberately.

In my experience the P-38 is a very strong high alt fighter and despite what the other poster said it should be able to prevail against most 109's at those types of alts where none of the 109's or 190's are really in their element.

Hope that helps.

ok...that does make it make more sense....as the time i mentioned going into compression, i did a split s to go after the 109. i was kinda feeling her out, and was doing a looooong slow pull.....which is most probably how i ended up compressed then.
 like i said, i'm not normally up that high, not even looking for buffs.........but it would've been fun to have been able to actually fight those guys, rather than flounder around like a fish outta water. 

[CAP1]

Looks like most the other folks answered the question, flying at altitude is completely different than the typical MA fights.  There are a couple fields in the TA at I think about 20k alt.  If you see me online and you want to play around at 20k+ let me know and we can head over there and stooge around and see if we can keep the birds from falling out of the sky (I think the last time I was up that high was for the DSG scenario so I could use the practice too). 

now THAT sounds like fun.....and when i can get in again, if i see ya, i'll pm ya?



thanks!

[BaldEagl]

In case you're interested here's a wikipedia article on mach tuck which seems mostly correct:  http://en.wikipedia.org/wiki/Mach_tuck

It's an interesting phenomenon.

[Soulyss]

That'll work, last time I was up that high I dove on a someone a couple thousand feet under me going after some buffs and I was thinking NOW I GOT YA and WHIFF! went sailing right past him because I lost elevator effectiveness, was rather embarrassing.

[Dawger]

MACH NUMBER and AIRSPEED vs ALTITUDE

MACH NUMBER is defined as a speed ratio, referenced to the speed of sound.


Since the temperature and density of air decreases with altitude, so does the speed of sound, hence a given true
velocity results in a higher MACH number at higher altitudes.

AIRSPEED is a term that can be easily confused. The unqualified term airspeed can mean any of the following:

a. Indicated airspeed (IAS) - the airspeed shown by an airspeed indicator in an aircraft. Indicated airspeed is expressed in
knots and is abbreviated KIAS.

b. Calibrated airspeed (CAS) - indicated airspeed corrected for static source error due to location of pickup sensor on
aircraft. Calibrated airspeed is expressed in knots and is abbreviated KCAS. Normally it doesn't differ much from IAS.

c. True airspeed (TAS) - IAS corrected for instrument installation error, compressibility error, and errors due to variations
from standard air density. TAS is expressed in knots and is abbreviated KTAS. TAS is approximately equal to CAS at
sea level but increases relative to CAS as altitude increases. At 35,000 ft, 250 KIAS (or KCAS) is approximately 430
KTAS.

IAS (or CAS) is important in that aircraft dynamics (such as stall speed) responds largely to this quantity. TAS is important
for use in navigation (True airspeed ± windspeed = groundspeed).

For purposes of aerodynamics and aerial fighting Indicated Airspeed is the deciding factor. True Airspeed is a navigation number. One would use True Air Speed and wind direction and speed to compute Ground Speed.

The higher you go the lower the indicated airspeed. The speed of sound decreases with altitude so Mach number goes up.

As you get higher and higher you get into "coffin corner". That is the corner of the flight envelope where stall speed and critical Mach approach each other.

In the Jet I fly we have a visual presentation of this corner on the EFIS display (Red hashed bars indicating stall speed at bottom of the speed tape and red hashed bars at the top of the speed tape indicating critical Mach) When the 2 get 20 knots apart life is interesting. There is no margin for error or maneuver.

You don't have this in AH of course but you can figure it out. You should know the clean stall speed of the J is around 100 mph depending on weight. The current mach number is displayed on the E6B. Critical Mach is .67. I would suggest flying at different altitudes and learn how far apart the two actually are and get a feel for the IAS that equals critical Mach at 5,000 foot increments.

It takes a smooth hand to fight effectively in the coffin corner. Ham fisting the controls will lead to departure from controlled flight or mach tuck. Fly with the finger tips and make everything deliberate and smooth. The other guy is gonna have as much trouble as you. Most fights that start up in the corner quickly go downstairs because most folks fly with a death grip on the stick. (A light touch will serve you well at low altitudes as well)

Just remember to take only what the airplane will give you and don't jerk the controls around and your high altitude fights will go in your favor.

[Ack-Ack]

hey guys.....not sure if i should put this here or in general discussion?


last night, i was in mw......having issues with my back, so i launched, hit auto climb, and went afk.

 came back, and i'm passing through 22k, so i went level. looked at the map, and see a LOT of cons and a single friendly near V38. i call him on squad vox, asking if he has vis on em. he did....he was a little below 20k, and called them all out as being above him. i found them. there was a gaggle of 109(F's i think) all around 20 to 22k.
 i climbed a bit more to just over 23k, let my speed come back up, and went in on them....sort of. i would pick one of the higher ones, and try to make a pass.

 the problem i was having though, was that i would get my stall buzzer, and the shudder of the oncoming stall with even just a gentle pull out. i was chopping throttle when i'd go in. on one pass, there was one i'd guestimate to have been about 20k, that looked like he was focused on a squaddie. i tried to pick him, and cut to 1/2 throttle as i dove for him. i then felt the shudder of compression,(well before i got near him) went to idle, full up trim, full right rudder, everything i could think of to prevent the compression i entered. went into it anyway, and couldn't recover till about 16k.

 so.....my questions?  how does one fight in the 38 at that alt? how does one fight against a 109 in a 38 at that alt? how does one prevent compression at that alt?

 i'm rarely up that high, and wouldn't have been had i not been afk for so long.

 and, yes, we all did try to drag em down lower, but i never heard any reports of any of them getting lower than 20k alt.

 i just couldn't believe that i had so much trouble performing a seemingly simple turn at those altitudes.


thanks!

The quick and easy explanation would be to use your throttle to control your speed more when above 20,000ft and watch your nose low turns. 

This is where throttle control is important, you can't let yourself get too fast when above 20,000ft without risking entering into compressability.  Unlike lower altitudes where you can keep the throttle up against the stops, you can't at high altitude. 

Another important thing is watch out on your turns.  P-38 turns best in nose low turns, but at high altitudes you have to be careful because you can lose it in a nose low turns by getting too much speed and either losing the advantage because your controls become sluggish with speed or worse case scenario you enter into compressability.

Rembember, fight upwards and not downwards.


ack-ack

[CAP1]

That'll work, last time I was up that high I dove on a someone a couple thousand feet under me going after some buffs and I was thinking NOW I GOT YA and WHIFF! went sailing right past him because I lost elevator effectiveness, was rather embarrassing.

 

sounds like exactly what i did to that 109 driver. if he realized what happened, he was probably laughing his arse off.......