I'll soon be training on a UAV with a GW around 400 lbs and a pusher power plant. I have heard in the past that the aerodynamics of small /rc aircraft are different than "full scale". Have no idea how or why that would be, but I can say my experience thus far trying to land this thing from a GS leads me to believe it's true. It really does seem to handle differently, some of the difference is control response delay+ the fact it's a pusher-- but I'm wondering if there is something else I'm not aware of. I seem to have had best results when I "drive" it ;instead of flying it.. some may understand what I mean. All I know is it's a *****, thing gets tossed around like a rag doll.

thanks for any input- i really know nothing about rc flying

400 lbs is WAY more than we deal with in RC. YOu're into Ulltralight territory witth that one. Full sized "rules" willl definetly apply. If it's getting kicked around then it's due to the design choices made by the design team and not related to it's size. But there's no doubt that the key element, the reynolds number operating range, is going to be similar to experimental homebuilts and ultralight aircraft and likely an order of magnitude over what us RC guys deal with.

I would agree with the above. At 400 # it should act much like a full scale. In fact a 1/4 scale piper cub at 15 or 20# or so will handle quite scalelike I am told. I do not quite understand the reason there is a difference in size,but I know that is the case. Take for example the way a real small model [1# or so] and compare with a 1/4 scale bird and you would see a lot of difference in the way it responds to commands.

Thanks, everything is relative lol... when I think 400 lbs I think small. At altitude its very stable, on final....not so much. A 12 kt cross wind i normally wouldnt give a second thought too blows it all over..

Sounds like your approach speed is too low.
I'd bump it up to keep more positive control during landing.

A 12 knot crosswind would likely give fits to an ultralight pilot as well. But their ability to correct by "seat of the pants" feel from being right there would be more immediate. Likely because you're out of that physical contact loop and have to rely on seeing a crosswind caused displacement before you can react to it is what is causing your issue. A pilot on board would feel it long before a video or transponder needle would show enough effect to make you react. In this matter us RC pilots DO share in the same issue since we react to our models being displaced and then have to deal with it. But once we see the model is moving in an unwanted way there's already momentum and significant displacement involved so we need to damp that motion and correct the heading or pitch movement. Again, a pilot on board would feel such a displacement during it's first accelerative moments and react to them before any significant unwanted movement occurs.

So your own flying of full sized aircraft is actually leading you to expect something that isn't there when piloting a remote craft.

Perhaps rate gyros such as wel use in our RC helicopters and I'm sure are used in a fancier package in the UAV industry could be used to replace the "feel by buttocks" seat of the pant deal for such corrections.