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Old 05-31-2012, 05:34 AM
BlackBerry BlackBerry is offline
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Quote:
Originally Posted by MadBlaster View Post
However, if you are above Vmax because your dive angle was steep, turning on your engine won't give more acceleration because you can not create excess thrust from your propeller at that point. Your TAS is too high. You are moving down and to the right on your efficiency/advance ratio curve for the given blade angle. Any excess thrust is coming from your dive angle/gravity.

You are wrong, LOL. I'll show you with La7's data. When La7 get Vmax=610km/h at low altitude with 1850 HP engine output.

power=thrust*speed

thrust=power/speed=(engine output)*(prop-efficiency)/speed=1850*0.735KW*85%/(610000/3600)=8KN=816kgf

The thrust force is equal to 816kg weight, that is 33% of la7's weight(2.5 tons).

The air drag force is also 816kg force, so la7's speed is steady=610km/h=170m/s.

If La7 dive in a angle of "A" in order to get a portion of gravity for help.

sin(A)=0.33

A=19.3 degree.

So you can turn off your engine/feather your prop and dive in a 20 degree angle, I'll bet that you can sustain 610km/h WITHOUT ENGINE and WITH THE HELP OF GRAVITY.

If you dive in 45 degree, I promise your "dead engine" La7 will be faster and faster untill lost your wing(>730km/h). When you reach 650km/h, you turn on your engine, the thrust is not as big as 816kg, but still around 500kgf, that is, you add "half ton" thrust to your diving La7.

Believe it or not.

In your opinion, la7's propeller will provide zero thrust @650km/h because this is out of "envelope"/Vmax.

Try it in il2 4.11m with your buddy's la7, you shut down engine when speed is above 610km/h and he is still using 110% power, and check if he could pulll away from you or not.

And try to shut down your enigne when you want to escape from the battle field by high speed diving(above Vmax) and when the enemy is chasing you with his 110% WEP. If you dare do that, you'll be caught by him even his aircraft is slower than you@level flight.

Quote:
Umm, who is chasing who here? Tempest has much more dive room than LA7. Push it to ~ 850 kph in your dive extension and zoom climb out from there. Don't waste the zoom energy to 600 kph unless your exiting the fight. Also, Tempest performs better at lower alt.
Cruising at 3000 meters and dive! In order to prevent the poor la7 from losing his wings, my Tempest MKV will carefully control the speed below 740km/h, and I'll show you how long I can stay in the high speed flying status.

Last edited by BlackBerry; 05-31-2012 at 05:42 AM.
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