I managed to get out today and blast through a bunch more batteries on my two Su35 MK2s... :)
When I first wrote my post flight report on the Su35 NAMCV2 (the camo one in the picture above which for brevity I will call the V2) http://migsrus.blogspot.ca/2014/10/frc-su35-mk2-namcv2-post-flight-report.html , I mentioned that I wasn't really able to assess the differences in wind stability between the two planes (the other being the white one on the right above which I will call the V1) as conditions were relatively calm. Today the wind was about 10 mph, but swirling and gusty, so a good "laboratory" to evaluate wind stability. In the post I linked above, you can also read the minor differences between the two planes, primarily the horizontal stabilizer/elevon setup.
The V2 is definitely "quieter" in the wind and in turns. It carves through the turns like a ski racer setting a hard edge, no side slipping, tail wagging, anything, it just finds it's line and carves it hard and clean. It is not a huge difference that you might find between the stock Su35 and these modified versions, but it is noticeable between the full flying elevon of the V1 and the horizontal stab/elevon setup of the V2.
So I did a series of figure 8 turns back and forth, changing direction of the figure 8s regularly so I could evaluate left and right turns in all aspects of the wind direction. With the fixed horizontal stabilizer, the V2 really just digs in and turns smoothly and stably, no hesitation or loss of energy at all. Again, not that the V1 is all over the place, but the V2 is just that more noticeably smoother. I also did several loops and other moves with lots of pitch required and the V2 is much more responsive in the pitch than the V1 and they now have the same amount of throw and expo.
The other nice thing I noticed today is that the V2 requires almost no rudder input to keep the nose from dropping or climbing in turns, normally only if it gets hit by a gust or is strong wind. The V1 often requires coordinated rudder input in turns in windy conditions as the nose tends to go up and the tail drops a bit when the lane gets turned on it's side. With the V1 it is almost like the back end is slowing down at times so a little added rudder keeps the nose tracking true. Not that this is a bad thing as I always need more rudder practice :), but it shows me that the V2 is tracking more true and stable through the turns as I rarely have to input any rudder to keep the nose tracking true.
If you really want to pull up quick (good if you are seconds away from crashing... :/), it just digs in it's heels and does a square corner even at about half throttle. However, having said that, once you are through the 90 degrees and going vertical, you want to get on the power and off the elevator as it can thrust vector stall (when the elevons start to act more as air brakes than elevons) a bit with such aggressive pull up maneuvers.
But even with smaller control surfaces, it will let you do the Sukhoi type "slow flip" loop at the top that you see in airshow videos. I can go almost to a stall, then just a little tap on the elevators and the nose pulls through quickly before it starts to tail slide or wing rock. If I plan it right that is, if not, I am executing some kind of WARM (wild ass recovery maneuver)... :/
In fact, this is where it gets really interesting to me...the moving surface of elevon on the V2 is about 15% smaller than on the V2, but because of the extra stability, reduced drag and turbulence of this smaller surface coupled with the horizontal stabilizer, less control surface movement is required for the same rate of turn... :) I would be "wagging" (wild ass guessing) to give you a percentage of reduced control surface movement, but I would venture to say it felt like about 10-15% less. The V2 only needs very subtle and smooth inputs to turn very sharply and smoothly.
Even more interesting is that I experienced the same thing with the RCP Mig29. When first doing the fly off between the stock Mig29 V3 (which up to that point I felt was the most stable park jet I had ever flown) and the stock Mig29 V4 (the first park jet I ever flew with the horizontal stab/elevon combination), I noticed much sharper turns and a "quieter" back end. Then as Stephan and I reduced the elevon size and Stephan optimized the area in the prop wash for thrust vectoring, even sharper, carving turns.
This is exciting stuff as it proves to me that this theory of having a fixed horizontal stab and smaller elevon setup works more efficiently now on two different airframes, not just the RCP Mig29 V4. Equal turn rate with less control surface movement means more stability, less turbulence as the control surface does not move as far and thus less drag. At least that is the evaluation I would give it after hundreds of comparison flights between the Mig29 variants and now between the Su35s.
As I am sure I have said before, I am sold on the fixed horizontal stab/elevon combo now on park jets. It is again a matter of having the amount of control surface you need, not having an over abundance of control surface causing more issues than they solve by increasing turbulence and drag which then cause you other problems. At least that has been my finding over a long period of testing and now seeing a second air frame proving the same points I saw with the modified RCP Mig 29V4s that Stephan and I have been working on.
Cheers,
Scott
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