Until our recent release of the NAMC Mig-35, our post flight reports had a very limited audience. Stephan and I work exceptionally well as a team, he spent over a hundred hours tweaking the plans to make them tight and precise and to incorporate inputs from my test flight reports and his own. I probably had the easy part, and was lucky enough to log over 400 Mig-35 test flights since November 2014. Stephan not only had to spend tedious hours adjusting the plans pixel by pixel, but then he had to wade through my "Migapedia" post flight reports as he nicknamed them. That was probably his toughest job reading those reports :).
Anyway, I have compiled some of the highlights of my post flight reports from our final plane, the one you see now in our pictures and the one you would build if you bought the plans (with a few minor housekeeping changes). These are the original reports I wrote (edited a bit to help them make a bit more sense) when I returned from the field after several different testing sessions. I hope they will give you a sense of what to expect of this plane should you choose to build and fly it.
Where we use the term PMI or polar moment of inertia, it might not be the exact scientific application of this term, but it is used to describe the distance from the front of the battery to the tip of the motor as this included all of the electronics which account for 60% of the weight of our planes. It is an easy way for us to refer to something with a short acronym rather than a longer description.
CG (Center of Gravity) and PMI (Polar moment of Inertia)
I am balanced essentially right on CG, maybe just 1/16” ahead, so very darn close. In the arc test, it performed beautifully, maintaining a nice gentle arc to level flight and didn't really start to drop it’s nose until it was almost completely out of speed. It is the best performing prototype of all of them in the inverted test, I needed maybe ¼ forward stick pressure to keep it level inverted, so I guess it might still be a bit nose heavy, but in normal upright flight it is bang on, with no trim at all needed in the pitch.
My PMI measured from the tip of the bullet nut on the motor to the front of my battery is 8.75”. Here is what my electronics bay looks like now with everything balanced.
You will notice in the picture above that my ESC is laying on top of the battery and is attached to the black velcro by a small piece of velcro on the side of the ESC.
For so long I was trying to put the ESC on the side of the battery bay 90 degrees to how it is in the picture. Well this was becoming a pain, as the ESC is just a bit wider than the width of the foam between the battery and top of the electronics bay. So after cursing that for awhile, I said to myself, “hey self, stop doing that, lay it on top of the battery, put a bit of velcro on the side of the ESC to keep it from moving around and your life will instantly get a whole lot easier!” And Shazam! It works like a charm...why does it take me so long to break out of these ruts sometimes….?! I was looking right at the forest and couldn’t see the trees!
If I haven’t said it before, one big advantage of balancing a plane on neutral CG is that launch is so much easier and less stressful. I launch with about 50% throttle, and it just flies away, no diving, pitching up, rolling, it just flies pretty much straight ahead until I can get my hands sorted on the transmitter and start giving it input. Makes the whole flight a lot less stressful when the launch is far easier and more predictable.
Turns and basic handling
All of the Mig-35 prototypes thus far have been very direct in handling and tracking, but now that we have the right size KFs helping to put the centre of pressure in the right location WRT CG, motor location, etc, this plane is the tightest of all that I have flown. It goes where I point it when I want to point it there, it doesn’t wander around or stray from whatever track I have put it on until I give it more control input. It does this effortlessly with no wasted movement or hesitation. At one point in the fog today, I literally had to keep it within about 100 ft of myself or risk losing sight of it, I pinned the throttle at about 55% and just yanked and banked to my heart’s content in a very small space with no hesitation, no loss of energy, it just responded when and how I wanted it to, just a true joy to thrash it around like that.
This plane loops, rolls, stall turns, split S like crazy and with the throws I am using, very scale, but very responsive. It holds it’s energy so well between moves when I have the throttle pinned at about 60%, I can transition from a loop to a roll to another loop to a split S, whatever, it will do what you tell it to when you tell it to and keep coming back for more. For real advanced guys that are much more skilled than me, I don’t think there are any scale aerobatics they would not be able to do with this plane.
With this new size KFs, gone is the “rotational lag” I was feeling with P3 (P3 was the third prototype I built from the original Mig-35 plans) coming out of high speed dives after doing a split S or when flying high speed aggressive pitch maneuvers, it just rotates how I want it to, when I want it to, amazing how just a little less foam on the KF makes such a significant difference.
High speed/full throttle
As with all the Mig-35s thus far, this beauty likes to go fast and does it very well. I did have a bit of torque roll if I hammered the throttle really hard, but with my new “two finger” method, I am a bit more gentle with the throttle input to get to top speed, so it gives me the time to feed in a bit of right roll to counteract if needed. The good news is that other than a bit of occasional torque roll, it just locks in and takes off straight ahead with no wobble, flutter and with my current CG and trim, no zooming or diving, very impressive. Can’t wait to try this baby with the NTM Prop Drive on 4S!
I have since flown this plane with an NTM Prop Drive 2700 motor, please read the results towards the end of this write up.
Gone is the constant/subtle wing rock I was experiencing with P3 in high alpha, this aileron/spoileron and KF combo lock it in solid to good scale (about 40 degrees AOA) high alpha. My spoilerons are deflected about ⅜” for best stability. I tried some high alpha without spoilerons, and it was OK, but there was more wing rock without than with, so spoilerons it is for me. I noticed on this plane that prop torque/prop wash pulling the plane to the left was not a problem, I am not using any differential spoileron at all, in fact because my battery is right of the centreline, the plane almost wants to pull right more than left. So needless to say, the prop wash still helps the plane turn left in high alpha really well but because of my setup, it turns right really well also without needing to play around with differential spoilerons. Again, there are better high alpha planes out there if you are a “high alpha hound”, but given all it’s other amazing attributes, it performs extremely stable, scale high alpha to allow pilots to continue to challenge their skills in as broad a flight spectrum as possible.
I know it is cliche to say “this plane lands itself”, but it darn near does, at least in calm winds and if I line it up right to give it a chance. Once again, because it is balanced so well, when I get to about 5 to 6 ft off the ground, I can just chop the power to zero and it just glides straight ahead, finding it’s own natural sink rate and other than a bit of elevator input to hold it off and flare, it continues the approach and landing with no bad habits unless I try to get cute with last minute rudder or aileron inputs. So once again, balance a plane properly and it becomes your friend!
So the testing is not completely done, still want to assess elevons only, elevons and rudder with this plane, this is the plane that I will definitely fly the most, it is my favorite setup WRT power plant and controls.
I can’t say enough good things about the plans and the plane, it flies as tight as it goes together and then some. I am so very satisfied with how far we have come from the initial mods we started making to the Mig-29 V3 til now, so much work, so many flights, all well worth it to see this plane fly! More to follow and I hope to get some video shot soon on a nicer day. Stay tuned to this channel for more amazing Mig-35 flight reports!
More inputs from the 2nd prototype I built from the final plans
This was the first plane that I had built right from the start to optimize servo and control resolution and it paid big dividends, overall flying felt very smooth, plenty of elevator authority even with only about 1.5” of travel. My aileron travel was ½” and the rolls seemed a little too quick, so rather than taking the throw percentage down (all three axes were at 100% rate in my transmitter), I dialed down the amount of aileron input into my elevon mix and that gave me rolls that were maybe a bit faster than scale, but not rifle bullet type. My rudder travel is about 3/4" one way or 1.5" total.
I balanced again on stock CG and after doing several arc and inverted tests along with some high speed runs, I managed to get my ESC positioned to prevent zooming and didn't have to use any trim in the pitch and it felt very balanced.
This is probably the biggest takeaway from today and I guess it kind of goes hand in hand with the video Dave Powers just released about the battery booster seat. It will be awhile before I experiment with that, but today I noticed that having my battery straddle the center line of the plane in the roll axis made a big difference.
I would say about 90+% of my planes I end up with the battery all the way over to the right to counter torque roll, but with this plane I ended up with the battery more in the center. This improved it’s slow speed handling quite a bit and I didn't experience the tip stall to the right that I had problems with on the first V5Z I built. Slow flying is much better balanced and the plane didn't break loose at all on me today in any flight envelope. In the limited high alpha I did, it also felt better balanced, still pulled to the left a bit of course with prop wash, but I could have corrected that with a little bit of differential spoileron except I never got that far.
So in future, I am going to try and fly with my battery straddling the center line of the plane in the roll axis as much as I can, even if I have to carry a bit of trim to get it to fly right, I think the overall balance and handling of the plane will be much better in the long run.
Test results flying the Mig-35 with the NTM Prop Drive setup
Wow, this plane is fast! I hit 100 mph (clocked with HK datalogger app on my phone, so there are some inaccuraccies, but these numbers are good to compare to other planes) on 3S with it today, a couple mph faster than any other Mig variant I have ever flown on 3S with the NTM 2700 motor, so it will be scary fast on 4S. I hadn’t flown in almost a week, so didn’t quite feel up to 4S action today, but will later in the week and get some video.
The plane handled the weight with absolutely no problem. I saw no wing flex at all, even though it is about 3 oz heavier than any of my other Mig-35s, it didn’t feel heavy. With it being so balanced and set up and flown with precision techniques it was no problem to thrash around. It just took a bit more room to fly it as things just happen so much faster with the NTM motor, even at half throttle.
WOW this plane is fast on 4S! High speed runs of 115/112/109/107 mph. The amazing thing is that the faster this plane goes, the more solid and steady it seems to get. I saw no elevon flutter, speed wobble, nothing. It just locked in solid and went amazingly fast. This is the fastest overall plane I have ever flown with the NTM Prop Drive setup on either 3S or 4S. It is also the best from a standpoint of still feeling light and quick on the sticks even though it is about 3 oz heavier than my other Mig-35s. It still changes direction very quickly and is very agile, although because it is moving so much faster, it does require a bit more maneuvering room.
Flying both these planes (I had also flown one of my lighter Migs during this test session to compare wind handling) in the wind was amazing, very stable, the odd bobble here and there as you would expect, but with the extra power, weight and momentum, the Mig-35 with the NTM setup would be my “go to” plane if I knew it was going to be really windy. The wind barely bothered it, there was almost no difference in flying it between dead calm and 10 mph winds, I was very impressed.
This plane with the NTM setup would be one of those planes to take to the field with a crowd around and seriously “light up the field”, even on 3S. It is so smooth, fast and maneuverable, it is unbelievably impressive compared to other NTM planes I have flown.
I hope these write ups give you some insight to what to expect from the NAMC Mig-35. If you have any questions or comments, you can post them here on the blog or on our RC Powers NAMC Mig-35 thread.