Tucano Maiden

On Thursday (yesterday) morning I maidened my Phoenix Models Tucano. The Tucano is a semi-scale model of the Tucano advanced trainer used by a number of airforces around the world. This one, in read and white trim looks very similar to a RAAF Roulettes plane (the Roulettes of course fly PC9s as any self respecting plane nut knows, but this still looks a lot like one).

She is a balsa ARF. I had my eye on this plane for a few weeks having noticed her on the shelf at Super Toyworld in Fyshwick.

I'm starting to think I might be the slowest modeller in the world, because even this almost ready ARF still took me a few hours to put together, although a lot of thinking time went into how to make a motor mount to suit a base mounting outrunner (I'm using one of those *cheap* ewatts R2212 1500kv motors).

Anyway, stupidly I didn't take any photos of the engine mount as I built it, but I used I 3 stacks of 10mm x 10mm x 25mm pieces of balsa, and then mounted a plyword firewall using each of the three stacks as a "leg" - this was then joined to the firewall. The engine mount with the Tucano would have been just fine, and would suit engines like Align BL450S.

However, I was just trying to save a few bucks, and have been massively impressed at how well the R2212 ran in the Zero. The Tuc' is quite a bit heavier, but she is no porker either. Takeoff weight of about 570g and she has the same prop setup as the Zero (7x5) and should be able to pull about 16A (so, 170watts or so). It's a long was short of 150watts per 450g, but it is still respectable.

I used a mixture of quality and cheap servos for the plane (actually most of them are cheapies - an HS55 looks after the elevator). Will be interesting to see how they go.

Anyway, the plane went together in a reasonably straightforward manner except for two things - the engine mount mentioned above, and the CoG. I was looking at the battery compartment (under the noise, secured by four little screws) and imaging messing around with a little screwdriver at the field, and not really being interested in the pain. Not to worry, without a battery the Tuc' almost balances exactly at the CoG. Oh great.

So, the battery is now mounted inside the avionics bay upside down against the bottom of the cockpit directly above the CoG. That is a bit painful...

The separate wing servos allowed a flaperon setup which I was happy about because I was worried she would have a stall speed just a fraction less than the speed of light.

However, by and large the ARF quality is pretty good. The covering looks good, all the hardware was okay, and the supplied decals do bring the plane to life.

So, on to the flight I guess.

There were a lot of reasons I shouldn't have tried to fly - let me run through them quickly:

1. My camera had flat battery meaning I had no photo of my completed Tucano. Talk about tempting fate.
2. The nut had slipped of the bottom of the quick link rudder linkage at the servo, meaning it could pop out during flight. Rather than lose the rudder mid flight I just took it out now and fixed it at a neutral position.
3. The oval was really wet and the grass was about half an inch longer than last time I saw it. I wanted to do a rolling takeoff but the Tuc's front nose wheel (non steerable) landing gear setup didn't seem like it would be ideal, and even though it had big wide wheels the ground was really wet.
   

The oval was quite wet after more overnight rain (its been raining a bit recently in Canberra - I think we have had more rain in the last two weeks than the last two years before that but maybe that is a slight exaggeration.

So, trusting in my perfect maiden record (no plane ever ruined on maiden flight) I decided to fly anyway.

There was almost no wind. I pointed the Tuc in the normal wind direction (after checking controls etc) and opened the throttle. She was taking a long time to gain speed and started turning slowly to the left. With no rudder at all I had no way to correct her. After she had taxied for 7 or 8 seconds I was convinced she wasn't going to get enough airspeed to rotate so I shut the throttle and wandered over to retrieve her.

I wanted to fly her, so decide to try a flaps takeoff, hoping I might just get enough ground speed to get airborne with the flaps. I was right. Opening the throttle she started her long left turn again, eventually getting airborne after maybe a 10-15 metre rollout (it was really really wet - DJ's Tigermoth had to be hand launched - it couldn't get takeoff speed from rolling).

Once she was in the air she was already very close to trim. Put on some altitude, brought the flaps, one click of left aileron to correct a little roll and then settled into trying her out.

First thing I wanted to do once she was at altitude was check out the stalls. Got her up, shut the power off and waited. I was surprised how much she slowed down before she stalled. Just the slightest hint of a tip stall. Some power, put the flaps on and then looked at how slow I could run on flaps (always thinking about the end of the maiden which always seems like the riskiest part to me). I was surprised at how slow she could fly - yes - she was still going twice as fast as DJ's TigerMoth stall speed, but she was much more manageable at low speed than I expected.

I pushed her up and down the field a few times, deciding the the recommended rates where perhaps a fraction high for the maiden (nothing could be done about it now though). I pulled one loop but didn't have the courage for a victory roll. A couple of times she seemed to take an interference hit, at one stage with her on her side above the trees I had a terrible feeling I was losing her, but whatever it was, she flew threw it, and was fine afterwards.

I didn't fly her for long - was the first outing for a new battery as well and felt I had pushed my luck enough for one day. Flaps on, got her setup, nice low throttle. She of course (it makes sense now) began losing altitude much faster than the zero in the same throttle position.

Noting she was a little nose down I got ready to flare her at the bottom of the dive. I close the engine to lose airspeed and pulled up so she didn't dig her nose wheel into the ground. She had more lift than I thought, and the controls where more sensitive than I would have liked. She nosed up and climbed (I thought she was close to stall speed - she wasn't). I desperately pushed down knowing what was next (I should have opened the throttle and gone around). She nosed down and it was all over an instant later.

Fearing some damage I rushed over - the fuse and cowl looked undamaged, but the nose was very close the ground. Once I got there it was obvious what had happened. The nose wheel undercarriage wire had bent back and absorbed the impact of the rough landing. Further, it hadn't torn from the balsa firewall, and all I had to do was straighten the wire. A bit of a lucky escape, but the undercarriage looks like it is well designed, just strong enough to absorb a very average landing, but not so strong it tears the aircraft apart so as to preserve its own integrity.

So, there it is - that's the flight report. I've messed with the rates a bit and am looking forward to giving her another spin at Lyneham tomorrow.

*late inclusion* Here is the vid from her flight at Lyneham following Saturday.