I haven't it installed right away, but I wonder if some of you could try...

 

I mentioned it on my comment to the 777 rolling backwards video...

 

Does X-plane flight dynamics model account for opposite roll rate with changes in beta (moving your ailerons) at negative G and Alpha (like, for instance, when you're falling on your tail, or landing with strong tail winds and your controls in roll get opposite response...) ?

:unsure: :Thinking: you lost me after: " Does Xplane.........." :lol:

What he's asking is, if I'm doing aerobatics and fly straight up until the plane stops, then starts a tailslide where it's traveling backwards, if I pull the stick back does it make the nose go down? Does pushing forward on the stick make the nose go up? Could I keep the plane in a tailslide longer than normal by careful control movements?

 

It's not that I'd ever want to do this, of course. But how does the airplane respond?

 

Hook

What he's asking is, if I'm doing aerobatics and fly straight up until the plane stops, then starts a tailslide where it's traveling backwards, if I pull the stick back does it make the nose go down? Does pushing forward on the stick make the nose go up? Could I keep the plane in a tailslide longer than normal by careful control movements?

 

It's not that I'd ever want to do this, of course. But how does the airplane respond?

 

Hook

remind me to never get into an airplane with Jcomm :lol:

I just thought of a better example.

 

If you're doing a hammerhead/wingover (fly straight up and just before the plane stops give full rudder and opposite aileron to make the plane pivot around one wingtip), if you mistime your rudder input and start to tailslide, would left rudder make the nose move to the right because of the backwards motion of the aircraft?

 

remind me to never get into an airplane with Jcomm

 

Hehe! He's a glider pilot and apt to try anything.

 

Hook

:unsure: :Thinking: you lost me after: " Does Xplane.........." :lol:

 

Me too, I thought he said "are those snow white ground textures out there", but then re-read it, and realized I was mistaken. :smile:

I'll give it a whirl when I get home.

 

... in the 777, of course.

Hehe, yes, have done a few tailslides in the Cobra 15, and lost the count on hammerheads, mostly on the K21 .... Great for simple aerobatics!

 

Thx for testing. Looking fwd for your answers. I just can't do it myself because my new home PC is in deep surgical phase... :-/ I'm sure it'll get ready for XP10.30, when we all all we really start AH!!! and WHOW!!!! (just a guess in the dark!!!!) :-)

Jcomm, you'll be happy to know that based on my non-real-world pilot skills in the F-22, this effect is modelled. I took off with full afterburner and immediately pitched up to 90 degrees. After reaching appx 10,000 feet, I killed the throttles and coasted straight up until all airspeed bled off. Once I confirmed I was falling backwards, I commanded the stick full forward, and the nose pitched back to about 120 degrees (estimate). The aircraft then got too wobbly to try testing full back on this attempt, so I regained control and applied throttle to repeat the straight up climb. Once again, I confirmed I was falling backwards with a 90 degree attitude (or as near as I could hold it), and commanded the stick full back. The nose pitched down to about 60 degrees (again, estimating), before the aircraft lost stability and began to tumble.

 

I would encourage anyone else who is so inclined to repeat this test to confirm. I am purely a recreational simmer and not a real world pilot, so take my test with a grain of salt.

 

I didn't try the 777, however, because after I posted above, I gave it some thought and remembered the F-22 was pretty good at tail stands, so that's why I picked it.

Great, thx for testing :-)

 

The aileron reversal would be another great confirmation of this type of situation actually being modelled (full AoA ranges, G-load)...

 

In real life I have experienced aileron reversal once, landing a glider under really adverse weather, wind strong shifting winds. On final,. already low, I approached the rw and a sudden shift of around 180º put me on a true tailwind situation. Before touiching down aileron reversal came to play :-) On tailslides or unproperly flown hammerheads control reversal due to "negative" speed vector can also come to play.

Here you go. I'll let the video speak for itself.

 

 

Excuse my rambling. Been up for 18 hours now. Time for bed!

Thanks, Jon, good video.

 

I've got my own question here.

 

Does XPlane model the propwash forces on the tail surfaces? For example, while FSX doesn't do this natively, the A2A Cub will lift its tail if you give it some throttle and a bit of down elevator. You can even taxi on the mains doing this. I understand other A2A taildraggers will do this as well to some extent.

 

More importantly, if you give a lot of rudder, then blip the throttle, does this cause the nose to swing around from the propwash on the rudder? Microsoft Flight didn't seem to do this, or if it did the effect wasn't very pronounced, making turns while taxiing at very slow speeds quite difficult. All of Flight's planes had castoring nose or tail wheels, so this was kind of an important effect.

 

Hook

Thank you very much Jon for taking the time to record the video! It's excellent and answered all of my questions! An image / video can sometimes be worth a thounsand words :-)

 

I am also glad to find that X-Plane's flight dynamics model does account for such "tricky" situations :-). I confess I had completely forgotten about that check until I saw the 777 video last week :-).

 

Thanks, Jon, good video.

 

I've got my own question here.

 

Does XPlane model the propwash forces on the tail surfaces? For example, while FSX doesn't do this natively, the A2A Cub will lift it's tail if you give it some throttle and a bit of down elevator. You can even taxi on the mains doing this. I understand other A2A taildraggers will do this as well to some extent.

 

More importantly, if you give a lot of rudder, then blip the throttle, does this cause the nose to swing around from the propwash on the rudder? Microsoft Flight didn't seem to do this, or if it did the effect wasn't very pronounced, making turns while taxiing at very slow speeds quite difficult. All of Flight's planes had castoring nose or tail wheels, so this was kind of an important effect.

 

Hook

 

Yes to all of your questions Hook :-)

 

That's one of the tests I ran long ago on my Ultra-Positive phase regarding X-Plane10... It's getting back with time... (the positive mood regarding X-Plane10 :-) )

I also posted the same at the MS FLIGHT forum by that time. Also I remember MS FLIGHT natively showed those effects, but I had to set some head wind to get the tail swing on propwash effect ;-)

 

In fact they are not limited to A2A's models in FSX either, and there are two records in the Airfile you can adjust to get those effects.

 

X-Plane's propwash effects are particularly evident using a taildragger (watch that prop strike while trying it!!!...).

 

Regarding the control reversal, I didn't test it with the p51d civil from A2A while I had FSX installed...

I installed DCS World with the Su-25 and tried the effect of "reversed" airflow on control surfaces, setting max tailwind on the runway and deflecting flight controls. Looks like DCS does not model the reversal of control surfaces actions when the airflow is reversed.

 

So, at least one effect that X-Plane natively simulates but DCS does not. :-)

I installed DCS World with the Su-25 and tried the effect of "reversed" airflow on control surfaces, setting max tailwind on the runway and deflecting flight controls. Looks like DCS does not model the reversal of control surfaces actions when the airflow is reversed.

 

So, at least one effect that X-Plane natively simulates but DCS does not. :-)

the free SU25 comes with a basic flight model.....the modules that you pay for have all the goodies :Peace: