Murmur

I think that the Spitfire, like many WWII fighters, had marginal longitudinal dynamic stability, probably also depending on c.g. position, throttle setting, etc. So a divergent phugoid seems a possibility.

Reached 133.154 ft / 40.585 metres with the F15C (PFM) :)

that is 35.348 metres (with running engines! :P )

Well, I guess this is a sarcastic post, but the fact is that according to this poll 60% of DCS owners use it also (or mainly) as a civil flight simulator, so your sarcastic idea might not be such a bad idea after all. :)

I edited the options listed in the first post to try to make it less misleading (cannot edit the actual questions on the poll). Of course I cannot change votes already cast. :)

Is this "counter-intuitive" effect already present during the takeoff roll? (I seem to remember you said so, but I may be wrong). If that is the case, then wind gradient cannot be the cause of it. :)

You're wrong, or better said, you should have added "for me", in that statement. As the results of this poll at the moment show, more than 50% of DCS World users, use it also for (or mainly for) civil flight simulation. As a similarity, take supercars: they're designed (among other things) to maximize performance in acceleration and road course lap times. And yet, most of their owners never take them to drag races, nor track days, but just drive them just to enjoy their performance, sound, handling quality and allure on public roads (okay, also to show off :) ).

Thank you, I changed the option to reflect your observation. :)

How do you use DCS World? 1) Mainly for military operations (including aircraft familiarization, training, etc.) 2) Mainly for civil operations (i.e. free flight, navigation, or just enjoying takeoff, landings, flying and systems operation) 3) I use it for both, or I'd use it for both if there were civil aircrafts EDITED FOR CLARIFICATION

Have you tried to establish if it happens out of ground effect? For example trying a "virtual" landing at altitude, gradually decreasing airspeed, etc. In order to discern if it's triggered by ground effect or by a certain airspeed range.