# of SAPP

[Shuffler]

The 38 is the master.. no one masters the 38 

The trainer of the 80th has spoken.

[vonKrimm]

Okay, i got 1 for the SAPP gurus: I was climbing at about 500ft/min around 30k (28k-29k i think) with a 225mph IAS having chased a 4-hog for two sectors because he wanted to protect his perk ride.  Suddenly I get compression syndrome going on my bird & go from a climb to a shallow dive, after turning off combat trim & fiddling with my trim tabs i get her under control but too late.  So, WTF happened?  I'd really appreciate any enlightenment that SAPP may have to offer.

[Guppy35]

THe key problem I see is you are flying way too high in a 38.  The best tactics are to fly low, 5K tops and wait for them to come down to you and play on your turf.

Seems like a complete waste of time to climb that high

[CAP1]

Okay, i got 1 for the SAPP gurus: I was climbing at about 500ft/min around 30k (28k-29k i think) with a 225mph IAS having chased a 4-hog for two sectors because he wanted to protect his perk ride.  Suddenly I get compression syndrome going on my bird & go from a climb to a shallow dive, after turning off combat trim & fiddling with my trim tabs i get her under control but too late.  So, WTF happened?  I'd really appreciate any enlightenment that SAPP may have to offer.

i've never been that high in anything in ah......but it sounds to me like you hit the alt. ceiling.


terrible waste of time going all the way up there though............

[SunBat]

Did u guys read why he climbed that high or did your Pavlovian response mechanism kick in?   

[Shuffler]

Your window for controlled flight grows smaller and smaller as your altitude increases. The thinner atmosphere causes your stall speed to go up and your compression speed to go down.

Generally since his compression speed at sealevel is greater than yours, so is his compression speed at that alt. He may continue to pull away.


You more than likely encountered a stall shudder and the birds nose dropped. From there your speed can increase quickly and and enter into a compressed dive. At that point if you were able to keep your nose from dropping too much you should be ok. Come off throttle all the way and work your rudders to create some drag. When you drop into heavier atmosphere you will be able to attain control over your bird as the window of controlled flight increases.

[CAP1]

[quote authorjavascript:void(0); =SunBat link=topic=273828.msg3431521#msg3431521 date=1253198367]
Did u guys read why he climbed that high or did your Pavlovian response mechanism kick in?   
[/quote]

he was chasing the corsair, that obviously didn't want to fight.


still a terrible waste of time.............like guppy said....let him come down low.........

but then...if he really wanted to go up there, it's ok too. 

[vonKrimm]

Your window for controlled flight grows smaller and smaller as your altitude increases. The thinner atmosphere causes your stall speed to go up and your compression speed to go down.

Generally since his compression speed at sealevel is greater than yours, so is his compression speed at that alt. He may continue to pull away.


You more than likely encountered a stall shudder and the birds nose dropped. From there your speed can increase quickly and and enter into a compressed dive. At that point if you were able to keep your nose from dropping too much you should be ok. Come off throttle all the way and work your rudders to create some drag. When you drop into heavier atmosphere you will be able to attain control over your bird as the window of controlled flight increases.

I had not thought of the respective compression speeds for our different a/c; in hindsight, this is completely intuitive.  Also having escaped my notice at the time was the fact that as alt increases, so does TAS; thus as you said in your 1st sentence "Your window for controlled flight grows smaller and smaller as your altitude increases."  Am I getting the concept correct?

As for chasing the unnamed foe, he (and a few buddies) had come into our V-base at ever increasing alt in several sorties and I was involved in laundry & cooking so could not devote my full attention to flying; backing up a sector & using a 7k base allowed me to do the home stuff and fly in a good mixture.  I guess he was POed enough by my killing in various rides (both of us switched rides each sortie it seems) at last to grab a perk bird.  No way was I gonna let him off the hook!  In the end I got PWed & he was engineless and rudderless (he saw my d@mned compression issue & turned back on me) so I turned for home as he went into a steep dive that I was not going to follow....I got the last blackout about 500ft from the runway...he was still gliding home.  All-in-all I had fun chasing that 4-Hog....pumped me up me go to that night's SnapShot were F4Fs slugged it out with Bostons and P40s!

[Captain Virgil Hilts]

i've never been that high in anything in ah......but it sounds to me like you hit the alt. ceiling.


terrible waste of time going all the way up there though............

If he hit the operating ceiling, HTC has some splaining to do. The operating ceiling is generally defined as the altitude at which the aircraft is no longer capable of maintaining a 200ft/min ROC. It should be about 35-36K, give or take a little, if memory serves correct.

I doubt they missed it that bad though.

It may be difficult to maintain a 500ft/min ROC at that altitude. If that caused a stall, he should have noticed it if he was flying the plane and not on auto climb. The stall might result in a compression situation if it took very long to recover and you were at military power or WEP.

[Dinan]

If he hit the operating ceiling, HTC has some splaining to do. The operating ceiling is generally defined as the altitude at which the aircraft is no longer capable of maintaining a 200ft/min ROC. It should be about 35-36K, give or take a little, if memory serves correct.

That's the service ceiling and it's 100 FPM climb rate with all engines operating and producing maximum continuous power.

Absolute ceiling is the highest altitude a aircraft can sustain level flight with all engines operating and producing maximum continuous power.

Sounds like vonkrimm came too close to the "coffin corner"

The coffin corner or Q-Corner is the altitude at or near which an aircraft's stall speed is equal to the critical Mach number, at a given gross weight and G loading. At this altitude the aircraft becomes nearly impossible to keep in stable flight. Since the stall speed is the minimum speed required to maintain level flight, any reduction in speed will cause the airplane to stall and lose altitude. Since the critical Mach number is maximum speed at which air can travel over the wings without losing lift due to flow separation and shock waves, any increase in speed will cause the airplane to lose lift, or to pitch heavily nose-down, and lose altitude. The "corner" refers to the triangular shape at the top of a flight envelope chart where the stall speed and critical Mach number lines come together.

[Raptor]

I have been at 33k in a 38L and did not suffer what he explained

[Banshee7]

I have been at 33k in a 38L and did not suffer what he explained

This must've been during AKAK's training clinic 

[mensa180]

[Scotch]

AhahahahaA

[BiPoLaR]

Our numbers are irrelevent, all that you need to know is that SAPP is everywhere.


ack-ack

So is HPV, but thats not a good thing
AKAK!!!!!!!!