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Archive for December, 2013
Posted by Late99 | Dec 21, 2013 @ 03:45 PM | 5,818 Views
Mini J3 Cub is sold by several different stores / web stores. It's cheap, aerobatics capable and quite "scale looking". And as such it's quite attractive. In this entry I'll try to summarize it's weaknesses and strong points.

Mini J3 Cub was my first proper RC plane. And boy it taught me a lot. Actually I'm running on a second airframe as the first one went into trash bin after countless of flights and crashes. Nevertheless, it taught me to fly and also gave me the inspiration to look into scratch building of planes.

After flying several other planes I have to say that a bigger (longer wingspan) trainer is better. The small J3 Cub is not very stable, it's very sensitive to wind and also requires some speed to stay in air. Bigger trainer usually is capable of flying slower. J3 Cub (at least those two I've flown) has a habit of tip stalling relative easily.

The biggest shortcoming of J3 Cub is it's 2mm motor shaft. It's very easily bent in a nose crash. Usually if you crash, you'll have also bent shaft. Two other common failures are tires and cockpit window part attachment. Foam tires come of from plastic rims and it's good to glue them initially. Same happens to cockpit window. Wing leading edge is held by it and it's badly glued to fuselage. In a nose crash whole window part comes loose. Some glue will fortunately remedy this.

J3 Cub is also relatively easy to get into tip stall. This combining underpowered stock engine and shaft problems means a lot...Continue Reading
Posted by Late99 | Dec 15, 2013 @ 08:57 AM | 5,805 Views
My Polaris build took longer than I expected, something like three months. I actually build couple of other planes during that time and that didn't help with Polaris progress. I'm quite impressed with Polaris design. Still waiting for good (winter) weather to maiden it, it's simply too wet and windy currently. This Polaris will be used mainly on snow and water, it probably won't see too much land based action.

The design is good, but the tough parts of the build are the aileron controls and motor wiring in the tail part. There simply isn't too much space. With proper stiffening (as per instructions) the airframe is rigid and I would expect it to be a superb flyer. The only extra strengthening I made was adding 6mm carbon square tube in the tail (vertically), otherwise I pretty much followed instructions. The finish was made by taping. Colored packaging tape for most of the surfaces only bottom surfaces were covered with more heavy duct tape to get more durability. Finding CG was easy, different battery types can be used easily by adjusting battery location.

Used hardware:
- Turnigy D2826-6 2200kv motor
- Red Brick 50A ESC
- 6x4E propeller
- Turnigy TG9e 9g servos
- Spektrum AR400 receiver (DX6i transmitter)
- 3s 2200mAh and 1500mAh batteries. Locations for both battery types measured and marked in the battery bay.

Used glues:
- Epoxy (with and without microballons)
- UHU Por
- Medium CA & accelerator
- 3M77...Continue Reading
Posted by Late99 | Dec 15, 2013 @ 07:50 AM | 4,544 Views
This is something really simple. But hopefully might help someone.

I use following construction to check CG on my foamies. It's not suitable for heavy planes, but quite nice for foamies. Anyway it's very easy & quick to build..

The base is cover from old broken CD-ROM drive. You could use wood block or anything like that instead. Then just hot glue two skewers into the sides vertically and glue small pieces of foam or rubber on the top of the skewers... And you've got perfectly good, quickly built CG finder.
Posted by Late99 | Dec 01, 2013 @ 01:17 PM | 3,888 Views
This is my plane hangar, ummm not, garage.

Well, plenty of planes anyway.

My trainers: Mini J3 Cub and Yak-12. Yak is very good trainer and has seen a lot of flying this summer, Mini J3 Cub not so, too heavy wing load on my setup (replaced the original motor with bent axel with Park 300).

Fun, self made depron planes: OSG, Yak-54 and the new 24" David (no maiden with David yet).

Then I've got two old ones from my friend when he decided to quit flying. A T-50 and Robotbirds Mustang. Both seem to have had a long and eventful life. Had to repair nose of the Mustang to get it airworthy, probably have to build new tail at some point, too. Haven't had opportunity to fly the T-50 yet. It looks bad (at least nose), but technically is ok.

And then the projects... Polaris and Puddle Twin 2. Should finish the nacelles for Puddle Twin and then it would be painting time... Finally, but not least: MX-2 for next summer aerobatics fun.

I also had tomhe's SU-31. But it passed away after very many hard flights and several minor and couple of more serious crashes. Very good plane, nevertheless. It's electronics serve now in the Yak-54.

More detailed stories will follow...