AH2fw190

[KgB]

So far i figured that we talking about 190.....

[Gianlupo]

Originally posted by Wingnutt
See Rules #16, #32, #10 subsection B, See Constitution, See Gettysburg address, See Episode 32 season 4 of Jerry Springer, See Spot, See Spot run.





Last edited by Skuzzy on 11-17-2007 at 07:44 PM

You're great, Skuzzy!

[Tilt]

Originally posted by Murdr
Acceleration and climb rate are both results of excess thrust.  Compairing climb rates translates to compairing expected acceleration within the speed and altitude range the climb data was taken.

Dumb question from me here..................

We can see the excess thrust at differing alts during climb at that IAS best suited to best climb rate.

As an ac accelerates its pure and induced drag (I always get the terminology wrong) increase, but do they increase proportionally? (to each other)

Take the La7 and a 190D. The La7's best climb rate is at a speed considerably slower than the speed used by the 190D to achieve its best climb rate.

Hence the speed where the La7 has  its greater "spare thrust" is lower than the speed where the 190D has its greater "spare thrust".

If the 190D cannot climb with the La7 at the best climb speed for the La7 then it would seem fair to say that at that speed the La7 would exhibit the greater acceleration in level flight.

If the La7 cannot climb with the 190D at the best climb speed for the 190D then it would seem that at that speed the 109k would exhibit the best acceleration in level flight.

Given this one would expect the La7 to accelerate at its best  at somewhere thru 260km/hr (161.5mph) upto the wep boundary (1600m) and again somewhere thru  255km/hr (158.4mph) from there to the 2nd boost boundary(2650m), and again somewhere thru 250>230km/hr(decending with alt) upto 5100m. (from original test data ac 45213276 April 1945)

I dont have any 190D data but I am sure some can provide it.

The mechanism that would seem to decide this is the changes in pure and induced drag and their effect on the "spare thrust".

It is a matter of record that even a 109G4 whilst not having the top speed of an La7 could out dive it once both were past the initial stage of acceleration. This would again seem to show that the rate of acceleration does change with speed and that the pure drag of the broader la7  reduced even reversed any acceleration advantage it had (over the 190D) at higher speeds when compared to its advantage at lower speeds.

so the question is..........

If we  generate an acceleration model from a climb model are we not simply taking a snap shot of the "spare thust" at the  best climb speed used and could it be that at other speeds the spare thrust is quite different?

[Murdr]

Originally posted by Tilt
If we  generate an acceleration model from a climb model are we not simply taking a snap shot of the "spare thust" at the  best climb speed used and could it be that at other speeds the spare thrust is quite different?

Thanks.  I should have went on to add qualifiers.  One being, that I am looking at both charts together to draw any general conclusions on acceleration.  Another is that I was specifically refering to level acceleration.  Prop thrust becomes less of a factor as dive angle increases.

You are correct that climb rate on its own does not provied enough information by itself to be useful for comparing acceleration.  Also, considering speed and climb rate together does not give enough information to plot comparative acceleration data across a range of specific speeds.

However, there is enough information there to draw some general conclusions on what to expect for comparative acceleration.  

If one plane outclasses the other in both speed and climb at a particular alt, we can expect that plane to also outclass it in level acceleration at that alt.
 
If the advantage is mixed, we can still look at the disparities between the two planes performance points and draw some conclusions.  For instance, if one plane has a marginal climb rate advatage, but has a significant disadvantage for top speed, we can expect any acceleration advantage to be at the low speed end of the spectrum.  It might even be so low a speed range that it would be irrelevent.

So at a glance there is some useful information on acceleration in those charts that can be used on the fly in the game (eg. If I break out of this turn fight and extend, what can I expect in this specific situation?).  However, as you correctly said, it does not tell you any specific data, but just an overall picture of the expected results.

I should have been more clear.  Actually, I didn't spend any time re-examining what I posted because I found the person it was addressed to had been banned between the time I started to reply, and when I clicked post

[bj229r]

Several folks on 200 got into the same (I guess:lol ) argument with this fellow about the same subject a few nights ago, similar results