A6M2 Glide ratio and fuel hits

[F4UDOA]

Dtango,

Don't you think it's odd that the A6M2's best climb speed is so high? 150MPH is about 30MPH over what it should be.

What does that say if anything??

[dtango]

I have no flight test data outside of AH besides what you've quoted on the A6M2 velocity for best-rate-of-climb so can't comment on the differences.  HTC is pretty thorough in their research and engineering.

By the way lift is not a factor in sustained climb performance.

Back to the topic of glide performance, the place to start is to determine what the expected glide ratio of the A6M2 is then compare.

Tango, XO
412th FS Braunco Mustangs

[oboe]

Using the .set speed command/alt-x at ranges from 150 down to 100 (can't use it below that) I got descent rates ranging from 4800 fpm to 3260 fpm.    This was an A6M2, 50% fuel, starting at 4000' and measuring the time it takes to pass from 3000' to 2000'.

When I plotted time x velocity vs velocity, I did see a peak at around 130 mph, but I can't say the plot resembled a parabola...
Still, 130 mph correlated to around a 4100 fpm descent.   I would've expected a number closer to what davidpt40 produced, but I can't come anywhere near achieving that.

As far as glide ratio being the lift/drag ratio and independent of a/c weight, isn't the lift vector a relative force, detemined by the upward force produced by the wing at a given speed/altitude minus the downward force of gravity, which is basically the weight of the a/c?   So while glide ratio may be lift/drag, the lift component is partially determined by the weight of the aircraft?

Thanks!

[funkedup]

Oboe did you plot glide ratio?  Glide ratio is the ratio of horizontal speed to vertical speed.

[eddiek]

I'm no aeronautical engineer, but I noticed with the inclusion of the A6M5b we have that they glide very poorly.
Why?  I have not a clue.
I've been at alt (or what I call alt....20K+) and noticed that the Zeroes glide distance is far less than say, a P-47.  Like others have said, you have to really stick the nose down to keep your speed constant.
I've had a P-47D-30 at 20K in the NDIsles terrain, ran out of fuel while rtb'ing, and I was able to glide from half a sector S of A45 all the way to A47.  Actually, it was a bear to get the thing slowed down enough to stick her on the runway when I got there.
Seems the Zeroes have too much drag.  I'm not sure how "clean" they actually were in RL.  But from everything I have ever read about them, the AH versions pale in comparison to the RL planes.
Example:  Last CT setup, I took an A6M2 up to 25K.  Why?  Cause the Allied guys were staying up that high, and I hate fighting uphill.  
Anyway........EVERYTHING I have ever read about the P-40's stated that they were a dog above about 15K....some sources say 12K was really the max alt you wanted to see in one, but I digress............RL accounts indicated that upstairs where I was flying, 20K plus, suited the Zero better than the P-40.  Not so, at least from my experience.  The P-40's were leaving me in the dust.  Maybe it was my crappy flying, but accounts from Allied pilots who were "there" said that being caught at those alts by a Zero was suicidal.  The P-40 was just wheezing along while the Zeroes were still going strong.
IMO, the Zeroes in AH have too much drag.  Furring at low alts against even F4F's I found myself stalling in turnfights, while my opponents seemed to stay in control.  The A6M's seem to bleed E even worse than the much heavier Jugs do, and that is saying a lot.
Maybe Pyro could look into some of this.  I confess I do not have documentation, at least not from he might call a reliable source.  All I have are the normal books and reference sources everyone else has.

[wetrat]

Originally posted by ra
Same with the Typhoon and Tempest.  I'd bet the problem is that all the other planes glide too well.

ra

The typhoon and tempest are extremely heavy... it's my understanding that they're armoured fairly well, and I know for a fact they had huge engines. Their glide ratios seem ok to me.

[dtango]

oboe:

Did you reduce prop pitch by reducing RPM to lower windmilling prop drag?  I did a real quick test of the the A6M2 25% fuel glide at 140 mph at low alt resulting in about a 1600 fpm descent.

Lift=Weight in level flight.  Whatever the weight of your a/c, that's the lift you need to produce to stay in level flight.  It get's a little more tricky in a glide since lift and weight are no longer vectors opposing each other by 180 degrees.

L/D is a ratio.  The ratio remains constant in a glide even with different aircraft weights involved.  Yes lift varies with weight.  However the L/D ratio remains the same because drag changes as well so you end up with the same L/Dmax ratio.  In otherwords the lift and drag change because of the different weights but the ratio remains the same.  I know it sounds weird but that's how the math works out.  If you have two of the same aircraft but at different weights they will have different velocities for best glide (lighter = slower best glide speed) but will have the same glide ratio.

Another way to think of it is that for best glide the angle of attack is always constant no matter the weight of the a/c because that's the aoa that produces the most efficient L/D ratio for the a/c.

Tango, XO
412th FS Braunco Mustangs

[Vladd]

Originally posted by F4UDOA
Don't you think it's odd that the A6M2's best climb speed is so high? 150MPH is about 30MPH over what it should be.

What does that say if anything??

The Zero in AH does enjoy it's best rate of climb if you manually set speed to 122, rather than going with the default autoclimb setting. The difference is slight, but consistent, and most pronounced over 15k.


Vladd