Official Nexa 1870mm DHC-6 Twin Otter Canadian Yellow (Balsa ARF) Discussion Thread

[ICM]

Just picked up the Twin Otter from a fellow club member. However, he flies Futaba and I use Spektrum. I installed an AR620 receiver and need to set it up on my DX9 transmitter. Unfortunately, my arthritic fingers make it very difficult to measure control throws in mm per the suggested rates in the manual. Does any one have the manual's suggested rates in Spektrum %'s for aileron, elevator, rudder and flaps? Thanks in advance for any help.

Anyone?

[Evan D]

No idea but I’d use a better receiver.

[xviper]

Anyone?

Agree with Evan regarding the RX. If you insist on using that AR620, then do a really good range check from every possible direction. IE, with the TX being ~100' from the plane and with someone holding the plane and turning the plane 360* (right side up and on its nose) while all the sticks are worked. Make sure your assistant is mindful of the propellers. Depending on if your flying site has any dead zones due to proximity to high power lines or other forms of interference, I prefer to use a RX that can accommodate a satellite RX as well, with at least one antenna going to the outside of the plane. On mine, I have one antenna sticking straight out the top at rear of the battery hatch.
Since my last post here, I have converted mine to 6s, using the 5-blade Scimitar props from the Eflite EC1500. I run a single 500mah, 6s LiPo. I also have differential thrust as I fly this plane only in winter off snow/ice and have floats.

Insofar as the throws are concerned, my % may not mean much for your application but I'll tell you anyway. It all depends on which hole in the servo arm you are using and which hole in the control surface arm you are using. This plane is quite heavy for its size and roll authority can be sluggish, so I maxed out my AIL throws to 125%, 30% expo. Elevator is at 100%, 30% expo. RUD is 125%, 30% expo. You can choose lower rates for your mid to low switch positions. For flaps, I've also maxed those out for landing flaps at 100% and a bit of ELE compensation at 10%. Go half that for take off flaps and 5% ELE comp. Note that this plane really does NOT require flaps for take off or landing. Using flaps for landing requires some finessing of the throttle during final.

[Denniswpb]

Get rid of the AR620 receiver!!!! They have had issues with them. I set my throws the same with all my planes at first and then tweak them if needed. I use only one switch (C) for all flight controls. Low Rate= 70% and 20% expo Mid Rate- 85% and 25% expo High Rate- 100% and 30% expo. Those are good setting to start with and I maiden my planes in Mid Rate. If you need less or more, it's just a quick flip of a switch.

[ICM]

Thanks for the replies. I maidened myTwin Otter yesterday. Rates at 100/85/70%. Flew mostly at 85%. Did not use flaps. No issues. She flew very well and stable in a 6mph quartering wind. Landings in the grass were smooth and easy. BTW, I have the AR620 in 5 other planes with dozens of flights and have never had an issue.

[xviper]

The flaps on this model is more scale size and as such, they aren't as effective as this ones of the real TO. So, using them or not using them produces minimal changes on how this model lands. By comparison, the flaps on the Flex Innovations TO are huge, but that plane was designed as a 3D foam model and I fly it with a completely different philosophy in mind.

[Denniswpb]

Just an FYI While at Joe Nall flying my Twin Otter on floats. I took off and on climbing out the hatch blew off. I didn't think too much of it but when I made a shallow right crosswind turn, the plane got wobbly and stalled, despite keeping the nose down and increasing power. The plane crashed into the lake and sank about half way, I did the "paddle of shame" and got to the plane with the front half under water. Both brand new batteries are now at the bottom of the lake as well as the nose cone. Fortunately, that and a busted windshield and cracked horizonal stab is all the damage.
Here is what caused the crash.... When the hatch blew off, the fuselage filled with air like a big scoop and because there is no vent hole on the bottom, it created excessive drag. That coupled with the additional drag from the floats and making that right turn caused the plane to stall. I looked at the hatch, and 2 of the magnets came loose from the fuselage, which caused it to blow off. I don't know why Nexa did not put a latching system on the hatch cover, but I sure am now! I would not trust just those magnets again! BTW, if anyone has a spare nose cone and a horizontal stab, let me know!

[xviper]

This thread spans 5 years and even my own tastes and flying style has changed with this plane. When it was on 4s, it was more than adequate and very satisfactory. However, as I started to fly more powerful planes and EDFs, I flew this plane more aggressively. Even then, it was "OK" on 4s. When I decided to keep it for good and fly it mainly in winter on snow/ice, I converted it to 6s and added counter-rotating 5-blade Scimitar props from the Eflite EC1500, along with differential thrust. With floats, it is very "sporty" and the diff. thrust is needed for turning on snow.

As a balsa "kit", it is within the realm and responsibility of the owner to survey every aspect of this plane and determine where and in what way to complete the assembly the best way possible. Insofar as the hatch is concerned, I used additional rare earth magnets to make for better contact points and I ensured that all magnets were glued in very well. I ripped out the ones that were already there and re-glued them to be sure. In nearly 6 years of flying, the hatch has never come off.

I've been lucky to never have damaged it in any "mishaps", so getting parts have never been a necessity. VQ is based in Vietnam. Since MotionRC is the sole distributor for VQ models (Nexa in this case) in N. America, I think you could send in a request to their customer service team to special order the horizontal stab and nose cone for you. I would think it shouldn't take more than a month or 2 to get such parts. Many years ago, Motion did a special order for me on a product that was only available in Australia. You may find them to be quite accommodating. Doesn't hurt to ask.

[Denniswpb]

I'll see if I can locate VQ models and ask them. No telling when MotionRC will get them in. Thx!

[Denniswpb]

Do you fly with one 4S battery or 2 4S batteries in parallel??? I've always flown with 2, but but happen to look at the manual, and it states just one.

[xviper]

When it was 4s powered, I used 2 x 3300mah Turnigy Graphenes mounted longitudinally. One was on the bottom and shoved as far forward under the seat. That left about 2/3rds of the battery sticking out behind the seat. The second one was on top, hanging partially off the rear of the bottom one. A piece of shelf liner kept it from slipping and both were held down with a velcro strap. Now that it's been converted to 6s, I fly it with a single 5000mah CNHL LiPo mounted laterally behind the front seat.
Mine now has floats and it's used as a winter snow/ice plane only. It will be coming out as soon as the snow pack is thick enough and hard. It gets the summer off.
If you didn't have any luck finding the parts you need, you could always learn to build the tail piece from scratch using balsa and monocote covering. The nose cone could be 3D printed.