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Tuesday, December 17, 2013

FIELD TESTING OF THE GRAYSON HOBBY SSV2 MOTOR IN MY F18 V3

Hi everyone -

I tested another motor in my RCP F18 V3 testbed plane today, probably the last motor I will test for a while... :)

Today I tested the Grayson Hobby Supersonic V2 (SSV2) 2212-6 2200 Kv motorhttp://www.graysonhobby.com/catalog/gh221206v2brushlessoutrunnermotor-p-398.html which until yesterday was still on the RC Powers Master Parts List... :( But no matter, some folks might have one laying around or are looking at it as a choice for this plane.

In the plane, it performed very much the same as the RC Timer 2212-6 2200 Kv motor, on the bench it was a tiny bit more efficient in that it drew less amps for essentially the same thrust as the RCT motor, perhaps due to slightly higher quality bearings, but it is tough to argue the price as this motor is $23.99 and the RC Timer motor is less than $10.

At the field today I tested the 6x4 APC prop and the 6x3 EMP prop, I noticed only a slight edge in initial acceleration with the 6x3 EMP prop and other than that the performance was much the same, maybe a little more endurance with the 6x3 EMP prop based on how much I had left in my battery when I landed.

My plane today weighed 18.5 oz with the 1600 Mah battery, I used a Turnigy Plush 30A ESC and everything worked just great. Good little combo, but again for price and equal performance I would probably have to go with the RC Timer 2212-6 motor if I was looking for a motor in this weight and power category.



Not the prettiest looking plane, but still flies awesome!

Cheers,

Scott

Monday, December 16, 2013

RC POWERS MIG29 V3 AT 25 OZ WITH NTM PROP DRIVE 2700 MOTOR

Hi everyone -

I just finished up my latest Mig29 V3 with a paint scheme inspired by a paint job of a Mig 29 of the 28th Guards Fighter Aviation Regiment which last flew the Mig 29 before being disbanded in 2009http://en.wikipedia.org/wiki/28th_Guards_Fighter_Aviation_Regiment. This unit fought with distinction in WW II and Korea and was awarded the Order of Kutuzov http://en.wikipedia.org/wiki/Order_of_Kutuzovand six officers who served in this unit were made Heroes of the Soviet Union and the Russian Federation.

2013-12-12 14.03.29.jpg

I have not put any insignia or decals on it yet, the cold, wet weather and decals don't seem to get along right now...:(

After watching and admiring all the amazing things that Airflow from the RC Powers group has been doing with his heavy Mig 29 V3, it inspired me to want to see what I could do with it in a weight range between where Airflow is and where I am with my lighter German Mig. I also wanted to build it so that I could try out the NTM 2200 motor on a 7x4 prop when that arrives from HK (probably not til after Christmas...:()

So my AUW with 2200 3S battery is at 701 grams/24.7 oz which is about 5 oz heavier than where I am with my German Mig. Most of the weight comes from extra reinforcement to handle the punishment of the NTM motors, the bigger motor, ESC and battery. 

My build -

  • 6mm Depron with Kf4 airfoils made of paperless dollar store foam. Constructed primarily with Foam Tac glue with a few dabs of other types of glue here and there as needed;
  • Power setup currently is the NTM Prop Drive 2700 Kv motor with 6x4 APC prop, Turnigy Plush 60A ESC, 2200 3S battery 45-90 C, I will also be doing some flying on this setup with a 4S battery. I just bench tested this motor and got 42.2 oz of thrust on a 3S and 54.3 oz of thrust on a 4S with the 6x4 APC prop;
  • control surfaces are elevons, ailerons (switch selectable as spoilerons for slow speed/high alpha) and rudders. I'm using a 6 ch receiver compatible with my Turnigy er9x setup, elevon and aileron servos all have their own channels, rudders connected by Y harness;
  • all leading edges bevelled and sanded as well as a good general sanding of the whole plane to provide as sleek an aerodynamic profile as possible; and
  • paint is acrylic craft paint from the dollar store brushed on free hand to create the camo pattern. The camo is granite grey, tan and forest green, the nose cone is pewter grey.
My thrust to weight ratio should be about 1.7:1 with the NTM 2700 on 3S which is just slightly less than my German Mig and my wing loading is 8.6 oz/sq ft, compared to about 6.5 oz/sq ft on my lighter Mig. I am interested to see how the higher wing loading handles. One key thing that Airflow mentioned in one of his videos after he lightened his Mig up a bit was how it didn't have quite the same momentum in aerobatic maneuvers as did his heavier Mig with the Turnigy 3648 motor, so since I am going the other way, I am interested in seeing and feeling how this plane handles at a heavier weight.

Mods that I made from the stock build -

  • opened up the prop slot back to give more room for the longer NTM motor;
  • arranged my servos and pushrods so that nothing runs in a way that it will interfere with the prop slot so I can try the 7" prop on the NTM 2200;
  • I cut two triangular vents on the sides of the fuselage and one each on the top hatch and bottom of the fuselage in the electronics bay to help maximize airflow over my components since with the 4S on the 2700 motor and the 7 inch prop on the 2200 motor will be pushing the gear pretty hard, I wanted to optimize airflow; and
  • I enlarged the rudder surfaces by moving the hinge line forward about 3/8" of an inch.
Just back from the field after completing the maiden and starting the "dialing in" process of my new 25 oz Mig 29 V3. I also took my lighter 20 oz Mig to the field to do a bit of a "fly off" to see what difference if any there were in performance and handling.

2013-12-13 09.09.30.jpg

Amazingly, the handling and performance even with a 5 oz weight increase was very similar between the two planes. I noticed with the heavier Mig and slightly lower thrust to weight, different motor and prop that the punch and acceleration was not quite as good as the lighter Mig, but I think top end speed was very similar.

The heavier Mig did require a little bit more pull in the turns with the higher wing loading, but was still exceptionally responsive and agile even with the extra weight. I would say the lighter Mig had a slightly faster "first step" response when put into a maneuver, but the heavier Mig caught up quickly and felt a little smoother through aerobatic sequences and turning. 

Initially I had to be a bit more cautious in turns as with the heavier weight I found it "carved" into the turns a little harder than the lighter Mig. Not that the lighter Mig feels like it is floating, but perhaps just a little more forgiving in the turns.

The heavier Mig carries it's momentum a little better through pitch maneuvers like loops and with the extra weight of the ESC just to once side of the centreline was more responsive in rolls, not by much, but a little bit.

Overall, the handling and stability in all speed regimes is excellent with the heavier weight, I tried a little bit of high alpha and it felt more stable at the heavier weight than lighter.

My CofG on this plane continues to be bang on 3" behind where the leading edge extension and the wing meet which I believe is maybe an inch behind the CofG on the plans. It trimmed up pretty easily, I moved the battery forward about 1/4" to get rid of any elevator trim and about 1/4" right of centreline to help compensate for torque roll.

So I am now excited for the weather to improve again, my window of flying closed too quickly today due to fog and heavy mist...:( in order to try it out on 4S. I will also eventually be trying the NTM 2200 on a 7x4 prop which will bring my thrust to weight ratio up considerably based on the thrust numbers Airflow got with this setup in testing, 58 oz of thrust versus the 42.2 I get with the 2700 on a 3S and 6x4 prop.

So both Migs are amazing, hard at this point to pick a favorite, the lighter Mig is perfect on dead calm days and I think the heavier Mig will be great when there is wind...:)


I managed to get some video shot of it flying, starting the "dialing in" process...:)

Cheers,

Scott