Hi.
i want to use Flip Mode with very big copter, but i don’t sure if it can be using.
citat from wiki:
Vehicle should complete the roll within 2.5sec and will then return to the original flight mode it was in before flip was triggered
i think that it’s imposible for my drone , 2,5s can be to short time for full flip
if it will be problem for pixhawk ?
Yeah you can do it , but make sure your copter height is more then you expect
Happy flying 
It’s absolutely critical that videos be made.
Just saying.
My concern is the roll rate described in the Wiki at 400 °/s. What happens if it can’t do that? I have tried Flip on craft up to a 12" prop but a 30" craft? Just not sure what would happen. On one quad the flip took up a lot of altitude as it lost quite a bit on the “reduce throttle” section.
I do have a video of that around somewhere…
Probably this is the only question of mass distribution around corresponding axis in relation to the particular motor(s) thrust gaining speed.
120kV Motors with 30" props is a lot of mass to get moving quickly!
I have used Flip Mode on an 18" prop quadcopter with no issues - but nothing more than that.
Maybe try maneuvering at high AOA in acro mode and then conduct a manual flip, that way you can switch into stabilize at any time to try to save the aircraft. Highly recommend a lot of altitude for these tests.
Perhaps it could be modeled in RealFlight and tested virtually. I have not done this (don’t own it) but I have seen some cool simulation work done with it.
Another question if it should be a flip, or flip in move i.e.barrel roll?
Flip Mode is a roll.
The aircraft will survive just long enough to get to the scene of the crash.
Flip is in the direction of the current pitch or roll stick, so you can choose to flip any direction you like.
As mentioned there is altitude loss even with small quads, so a big aircraft could probably drop a long way.
We’ve done rolls, tumbles and so on in acro mode, and flips using a flip switch all with about a 500mm quad. I don’t think we’d be trying anything bigger than that though - the downwards momentum would be significant.
Ha, yeah! That sudden gust of gravity
Escapades like this usually start with “Hey, some body hold my beer…”
The only way I could envision this being successful is if each motor had a helicopter style variable pitch prop with symmetrical blades
Prop speed would be held constant by a governor and blade pitch would be controlled via servo driven swash plate.
For a quad this would require 12 servos (3 for each CCPM swash plate) and some real fancy mixer programming.
Now that I think about it a real smart guy named Curtis Youngblood came up with a quad that used heli tail rotors and a belt drive power train…
Genuinely curious as to why you need to flip a large copter?
Yeah same here when I try then then may-be 30M height on 1855 prop with 340kv and nearly 10M height lost during flip ( ~6 Kg copter weight )
In my case it’s sooo much excitement and I can’t describe my feeling in here just try it , when copter flipping and my heart beat racing that time ohhh my god. 
Fair doos sir! Balls of steel I would say. I think what you really need to do is get into 3d heli flying. The same excitement, much more scope for wild tricks and a much healthier wallet at the end of it compared to acrobatting an octo of your size! That is not saying for one second that your wallet will be healthy after flying 3d helis! 
, absolutely fantastic when your wallet is full but when wallet get empty then per parts searching on low price that time kill my excitement 
, but anyway it’s soo much fun.
Happy flying
This is the video I tested, 1300mm octocopter
This copter will be dropped from very big height with stopped propellers.
before the dress rehearsal i want to be sure that it can fly perfectly also after big rotation or start from upside down position etc.
test on model
full size
