Lift to Drag Ratios Compared

[JG27_PapaFly]

Originally Posted by AndyJWest

here seem to be some 'ground effect' factors that can kick in, which could possibly be distorting the results slightly - you might de better to test from say 1000m to 500m, rather than from 500m to sea level.

Ground effect is a decrease in induced drag and only relevant in very low-level flight up to an altitude equaling about the plane's wingspan. BTW i've specifically tested whether ground effect is present in IL2FB some time ago, the results were a clear no. Which is OK, the effect is not THAT big or relevant in RL except during flareout. No, i stand by my experimental setup, it's clean.

[AndyJWest]

Originally Posted by JG27_PapaFly

Ground effect is a decrease in induced drag and only relevant in very low-level flight up to an altitude equaling about the plane's wingspan. BTW i've specifically tested whether ground effect is present in IL2FB some time ago, the results were a clear no. Which is OK, the effect is not THAT big or relevant in RL except during flareout. No, i stand by my experimental setup, it's clean.

Ground effect is modelled, in IL-2 '46, and can be measured. One of the TD team confirmed it was in the 4.09 code, and I did extensive testing using my prototype autopilot setup (though you can demonstrate it without): There is a long thread on the subject over at the Ubi forum: http://forums.ubi.com/eve/forums/a/t...458#3121062458. Note that there seem to be two different 'ground effects' modelled - a 'true' effect that only kicks in at about half-wingspan and below, and a rather curious terrain and time related effect that seems to only occur with the 'wind and turbulence' on (even in calm weather). I think the conclusion we reached about the 'true' effect was that it didn't work in quite the way it should, but was definitely there. Whether 4.10 has been altered in this regard, I don't know, though I believe it was discussed.

[JG27_PapaFly]

Cool Andy, good to hear they've implemented ground effect. I did my ground effect tests in a way very similar to yours, but before 4.08.
Taking into account that real ground effect is only there between 0-10m, it has no significant effect on the average sink rate measured over 500 m of altitude.
I've also experienced "the other" ground effect. I reproducibly experience it as a sudden turbulence when i pass above a coastline ingame. However, it had no effect on this test, as i flew above water at all times. I even have all tracks, really boring stuff though

[AndyJWest]

My gaming PC is currently out of action, otherwise I'd repeat a test or two with 4.10, to see if anything has changed. With regard to testing, I'd recommend doing this with 'Wind and Turbulence' off, as with it on you can get different results depending on the time of day! As you say, the 'true' ground effect is unlikely to affect your results in most cases, but the W & T pseudo-ground-effect seems to occur at significantly higher levels. All rather strange...