Bit of a "Blue Mig Group" performance at the field today (groan... :/ )... :) I had a chance to do a decent "fly off" between my NAMCV1 (the mostly blue plane on the right) and my NAMCV2 (the blue camo on the left).
It was an exciting day at the field today, almost too exciting... :/ I think due to the vibration I might have been getting from the older motor I was using in my V2 that the motor mount started to loosen! I managed to get six good flights, then on the seventh flight it started to make a lot more noise than usual, so I landed as quickly as I could. Fortunately, the motor mount didn't completely break off, but part of the glue joint was broken. So all is good and nothing a little Gorilla Glue won't fix... :)
It was another windy fall day, so I really didn't evaluate any slow flight or high alpha handling, but I find that a little wind brings out the true character of a plane and amplifies good or bad behaviors. I now have 36 flights on my V2, so I feel a bit more comfortable doing a valid comparison between the two planes. I now have 136 flights on the V1, so I know it very, very well.
Just as a recap, here are the differences between the two planes -
- V2 is a bit lighter 0.7 oz/20 grams lighter;
- aileron and elevon servos and Rx are all moved about 1 and 3/4" further forward on the V2 than the V1, concentrating more weight in closer vicinity to the CofG;
- V2 has almost 60% more moving rudder surface and vertical stabs are 3/4" wider/deeper at the top; and
- ailerons are 1" wider in span and 3/8" narrower in chord.
All other aspects of the planes are the same including all throws and expos and luckily I have been able to balance both so that I can fly with zero trim in all axes.
So since today was a bit windy, 10-15 mph winds, I decided to evaluate fairly simple handling and aerobatics, lots of turns at medium to high speed, loops, rolls and stall turns.
There is definitely a difference in how these two planes handle and perform. Not the "oh wow" difference say between the stock Mig and the V1, but rather differences that can only really be seen when flying repeated maneuvers and focusing on how the plane feels and performs. So that is to say that the V1 is an awesome plane, but depending on what you are looking for, the V2 is just that tiny bit better in a few categories.
Turns
In medium speed turns, say 50-60% throttle, the V2 is just a bit more stable and tracks just that tiny bit truer. It still is affected by the wind, but I would say it is noticeably "quieter" in these medium speed turns. I'm suspecting this is due to the slightly larger top surface of the vertical stabs and maybe a little bit to do with the slightly extended ailerons which are now about 50% of the total trailing edge of the wing. The V1 ailerons are about 40-45% of the trailing edge of the wing and deeper in chord, the amount of moving surface is about the same.
At higher speeds, say 75-100% throttle, there is really no difference, both are very stable and locked in through tight, high speed turns.
Loops
In large, sustained loops, both planes were pretty much equally stable and tracked very true. Because of the forward distribution of weight on the V2 compared to the V1 that "first step" when I pull back on the stick is a little quicker, but after that everything is about the same.
In tighter loops, the V1 tends to get bounced around a bit more and does not track quite as true unless I keep on a bit more speed than with the V2 and feed in rudder input. I rarely had to use any increase in speed or rudder to get the V2 to track straight and true regardless of the size of the loop. Again, perhaps due to the redistribution of weight and the vert stabs, but not sure, just a noticeable difference.
Rolls
In both slow and tight rolls, the V2 is more responsive and tends to track truer, perhaps because of it's lower wing loading and the aileron shape. Not a huge difference again, but noticeable after repeating enough rolls with both planes. The faster the speed, the smoother the V2 handled the rolls.
Stall turns
Both planes perform very smooth, direct stall turns with little to no opposite aileron input required (except to compensate for pilot error/skill :/). With all the extra moving surface, the V2 just requires about 25% less stick movement to execute the same maneuver as the V1 with it's smaller rudders. As Stephan mentioned in a recent post, it is a trade off, if you like to do knife edge type maneuvers, then the full hinged rudder although having more authority in other flight regimes will make knife edge flying far more difficult.
So both planes are excellent performers, there is no doubt. They both are a blast to fly even with slightly different characteristics. Although right now I might be leaning slightly towards the V2 as being my slight favorite of the two, I want to log several more flights before really giving my final verdict.
One thing I have been noticing with my V1 over the last 10 flights or so though is that my CofG seems to be slowly "migrating" even further forward... :/ I started to notice a bit of zooming in high speed runs, so I double checked that my elevons and all other control surfaces were still centred and true which they were and the zooming continued. So I slowly started to move the battery forward a bit at a time until now it is 1/2" further ahead...What the...?! I pray that this tendency does not continue too drastically as I now have my 2200 battery all the way up against the bulkhead to get it to fly with zero trim in the pitch.
Since I will be swapping out the Focal Price motor for the NTM 2700 motor very soon, I might have to consider a whole new weight distribution setup to get it to balance since the NTM motor is an oz heavier than the FP motor and I also want to put heavier MG servos in for my elevons. I might have to shift the servos forward somewhat as well as my Rx and the heavier 60A ESC I will need with the NTM motor.
I find it very interesting the difference in CofG placement between the V3 and V4 Migs. The motor on the V4 is almost 1" further forward than on the V3 and I have been flying with my CofG 3/4" of an inch ahead of stock on the V4 where with my V3, I was regularly flying with my CofG about 1" behind RCP stock. In fact my CofG on the V4 is right about where the wing break occurs at the intersection of the LERX and the wing. On my V3, it was over 2.5" behind the wing break...interesting stuff. Perhaps the enlarged wing, larger rear deck plate and other things have significantly shifted the center of lift and center of gravity on this plane from the V3 to the V4.
Since I don't frequent the RC Powers forum any longer, I don't know if others have been experiencing this phenomenon, but to have it happen to me in both stock and modified planes, it makes me wonder if the stock CofG per the plans isn't off somewhat. To have the same thing happen to me on three planes is a bit more than coincidental I would think...but oh well, I have managed to balance them OK, I just lose some flexibility now with my stock Mig and the V1 to be able to use lighter batteries as they won't have enough weight forward to keep the nose down without inputting significant down trim.
I also learned another lesson today about components and how they are not all created equally, but will discuss that in another post... :)
Cheers,
Scott
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