Fw190 Speed Testings for AH2

[bunch]

Originally posted by Tails
I'd love to argue,  but I did a little checking to see if I was right, and I wasn't wholely...

Anyways, density of the object does play into terminal velocity. BUT the density of the medium (IE Air) does also play into it.  Lower altitude, denser air, lower terminal velocity. Higher altitude, less dense air, higher terminal velocity. Vacuum, no terminal velocity.

EDIT and here I am trying to argue through a typo...you meant 'leaving' instead of 'leave' in that post, didn't you?

"e" and "g" are not so different.
dont go around labeling everything, just be free, man....i was assuming same medium for the terminal velocity comarison "of course"...apparently i assume you can read minds over the internet also

[GScholz]

Originally posted by Seeker
I know that seems logical; but I know also that gliders often carry (dumpable) water ballast which improves performance in some regimes.

I don't pretend to know enough about aerodynamics to explain it.

CG balancing. If the pilot is a flyweight or hefty it is better to add a bit of ballast than to fly with constant elevator trim. Some planes pump fuel between fore and aft tanks to achieve the same, but for small planes gliders are of course the ones most affected by the added drag of trim.

[Tails]

Originally posted by bunch
"e" and "g" are not so different.
dont go around labeling everything, just be free, man....i was assuming same medium for the terminal velocity comarison "of course"...apparently i assume you can read minds over the internet also

Nope, cant read minds. But sometimes I go and screw up thinking I can.

[dtango]

* No difference in speed between 2x 20mm load outs and 4x 20mm loadouts for the A-5 and A-8. Maybe HTC forgot to add in(or remove) weights for those two guns, or maybe the weight of the guns and ammo for 2x 20mms isn't as much as we would expect.

The contribution of the additional weight to incremental induced drag is generally negligible for max level speed situations.  At max level speeds parasitic drag dominates overall drag while induced drag is a pretty minor factor.  The incremental change in aoa for the additional weight is most likely pretty insignificant resulting in no noticeable contribution to increased drag given the high speeds associated.

Tango, XO
412th FS Braunco Mustangs

[Naudet]

Mando, your are just to funny, actually HoHun and i proved that curve number 4 is correct, maybe a little bit optimistic but still correct and therefor that FW performance calculations are not way off as others might claim.

Henning doesn't point out that they are none representative for a D9 B4/MW50, cause he knows that there are no flight tests for MW50. Neither FW or the LW did them, because after the accidential crash of the first MW50 prototype the tests were only done on the ground. And so far noone could dig out any flight tests for D9s with MW50 from any archive.

I provided Henning with those tests, because we needed material from which we could get the drag data of a production series plane so that Henning could use that drag data and put it together with the JUMO213A power curve.

All those three plane are serial production planes, they are very representative for the D9, the discussion between Henning and me was about the exact and detailed condition of those planes not about them being unrepresentative.

006 too draggy, without MW50 (115l tank used for fuel), with 4350 Kg, incorrect propellor and what is described as "untuned" (new) engine.

You are mixing up to tests here, the one we used to verify and crosscheck the powercurces has the 006 in standard serial production condition for early 1945. The untuned engine and D12 prop were used in a different test for range measurements.

This gives the following performance compared to curve 4:

0.0 km 596 km/h 606 km/h
2.2 km 634 km/h 646 km/h
3.6 km 633 km/h 646 km/h
6.4 km 689 km/h 694 km/h
8.0 km 660 km/h 665 km/h

Funny, the data we got for 002 with ETC504 (002 had polished surfaces, this btw explains why 006 seems so much draggier, cause it had no polish) matches the AH speed curve for MW50 almost spot on.
It manages 370mph@SL which is just 2-3mph faster than AHs D9. 2-3 mphs are negligible, thats within productions variation. Even if some D9s managed 377mphs@SL with ETC504 the 10mphs speed difference to AHs D9 would be within production variation (10mphs are roughly a 3% difference). No need to change anything or complain about AHs D9 just doing 367mph with ETC504.

And that's why i am argueing against you.  You always pinpoint out that single calculated chart in any thread and mention it as it would be the final truth. While i know through my researches and analysis - with the much appreciated help from Henning -  that there is actually no final truth. The more sources i dig up, the more plane tests i get, the more questions and uncertainties arise.
Real planes have performance spans, and for the D9 i have a pretty clear picture of how wide this span is. And as long as AHs D9 is within those borders - and it is - there is no need to call for a change or complaining.

[Schutt]

Note that the P38J does not loose any speed for taking off with droptanks and droping them.

Well, lets say it can not gain speed from not using droptanks, guess the pylons are mounted fixed and cant be removed.

Now here comes the question ... are the official numbers for P38 speed with droptank/bomb racks? would think they measured clean P38s.

[Kweassa]

Schutt, look at the how the droptanks/bombs are mounted on the P-38J. They are strapped onto a fixed hardpoint at the wingroots. It doesn't use a separate universal rack like the 190s.

[MANDO]

Naudet, calculations are not always optimistic, but should be representative for most of the real planes (considering that these planes are within the deviation limits of the parameters used into the calculations). I would expect calculated speed +- 3% as a credible margin, not just calculated speed -3%.

BTW, you said you had the calculations used (in a page not posted, but from the same source as the chart). If these calculations shows formulae and parameters, drag used for the calculation should be present there, as well as total power curve and propeller parameters, and also the weigths.

AH wise, it represents -9 mph compared with curve 4 (or -18 mph if we add a +3% to curve 4 as most optimistic value). AH wise that speed is just what would put the D9 into Tempest/La7 leage at low alts.

Now it depends on everyone particular point of view to consider that ok or not.