ST Model Cessna 350
This morning I ordered the ST Model Cessna 350 as my second 4-channel plane. I wanted another plane as a backup - I would prefer to design and build my own after this point, but at least this keeps me flying if my trainer has any problems. Plus, for a foamie it looks gorgeous. Pics & Videos coming soon. I hope!
[Note: this plane is now also sold as the Flyzone Cessna 350 Corvalis, Hype Cessna 400 Corvalis, T2M Columbia 350 and probably a few other brandings as well. I really like the colour scheme T2M's chosen - you can see an example here]
Wing Loading: 44g/dm2
Wing Area: 22.3dm2
Last edited by Ben-M; May 22, 2011 at 11:33 PM.
It lives! The kit arrived yesterday and I spent a good couple of hours last night with my four year old son putting it together. I video taped the assembly, but it took too long and the camera battery died - I like to take my time when building so as not to make any silly mistakes. My son spent most of his time playing with the screwdriver set and enjoying being allowed up late.
Observations so far:
1) The kit quality is much better than the Ego/Arttech 182.
2) The manual is clearer and better translated, but still suffers a few translation errors.
3) There are only four servos, which means that both ailerons share a servo and both flaps share a servo. Functionally this is adequate, but it means I can't be creative with radio programming.
4) The wings are clearly intended to remain joined even in storage. At a 1.4m wingspan this is a little challenging in my small car.
5) There is scant room in the fuselage for bulky radio gear. I got a used AR7000 with this plane and I have trouble getting it to fit - not to mention there's no easy place to stash the remote receiver.
6) A short motor test suggests there's plenty of grunt available from the 9"x5" prop at full throttle.
7) Usual issues with foam exist, such as the control surfaces feeling a bit soft - if they've been rested against something they will be a little warped.
8) Fitting the horizontal stab so that it was correctly aligned was idiot-proof, whereas with my 182 it was a little less than satisfactory.
Maiden flight will be Sunday, flight video and photos will go up then.
I spent a lot of time last night fiddling around with the plane, trying to get it visibly trimmed out correctly. Some more general observations:
- The AR7000 is simply too big for it. I swapped the AR6200 out of my 182 and put it in this plane, where it fits nicely. The remote I tacked to the side of the canopy. This also has another advantage - the AR6200 has few flights on it and I'm pretty confident of its quality. The AR7000 was second hand and I don't know its history, so I'm happier putting it in my older plane.
- The foam is very different to the Art-tech plane. I believe the ST Model plane is EPO, the Art-tech one is EPS.
- Ailerons: Initially, the servo "centred" off-centre. So the servo would throw further in one direction than another, giving the plane very little left-aileron and a great big wad of right. I found that I had to loosen the servo horn, apply a subtrim offset in the DX6i to choose a good centrepoint, then retighten the control rods to that point. This gave the ailerons an even throw.
- Flaps: These are virtually impossible to get symmetrical. One flap appears to be shaped slightly different to the other. Both flaps TE warps upwards in the middle slightly, which is less of an issue, but the angle of extension seems slightly different between them (perhaps due to a twist in the mounting of the fowler hinges). The result is that I'm almost certain that applying flaps will result in a slight banking tendency. I predict ailerons being mixed with flap deployment.
- DX6i limitation. The DX6i only has a single position flap. The ST Model manual for the RTF boxed transmitter indicates an intended two-stage flap deployment, with ~15 degress for takeoff and ~30 degrees for landing. While I can program the DX6i to provide multiple stages by combining a mix (&switch) with the flap switch, this ultimately isn't foolproof - it will be easy to confuse which flap extension is being used, and it uses up another of the (limited) two mixes available. A bit lame, in my opinion. Rather than fight it, I'm giving in and planning on simply not using flaps on takeoff. The motor has plenty of grunt and the flying field plenty of takeoff space. I'll be surprised if it really needs flaps on takeoff.
- Cowl. I've seen a video of the cowl flying off during high speed flight. I can see how it could happen; while I don't plane on running that hot on the maiden, I plan to eventually adjust the cowl connection to make this a little more robust.
Maiden flight yesterday. Flight video will be up tonight. After the obligatory trimming, I spent most of the flight at altitude getting a feel for the plane's stall and low speed behaviour so I could bring it back safely. A little aerobatics and lower circuits preceded an incident free landing.
The 350 flies relatively well, with the following observations:
- The flaps will take a bit of practice. I wasn't game to deploy them when flying low, as they make a dramatic difference to speed and I didn't want to risk a stall at low altitude.
- Visibility is a big issue. At a distance it is very difficult to determine whether or not the plane is inverted. I think I will airbrush one or two large triangles to the wing undersides to help with this.
- Trimming is going to take a bit more time.
- The plane will fly inverted, and loop inverted - easier than my high wing trainer, but not nearly as easily as a symmetrical airfoil aerobat. Rolls are okay, but sloppy technique on my part makes it hard to judge just how crisply it'll do them.
- It'll fly nicely on half throttle, though it gets very mushy in the stall.
- Stall is well behaved for an intermediate plane, no ugly wing drops.
- Undercarriage works well on park grass.
- For a foam plane, it looks great in the air at the park amongst the more common warbirds and 3d fliers.
- Takeoff and landing without flaps is fine; I landed a little probably a little faster than I'd have liked due to still being concerned about stall characteristics.
Before I left for the field, I balanced the plane, and discovered that it was nose-heavy outside of the range documented in the manual. There was nowhere available to install additional weight, so I ended up cutting a hatch into the tail just before the glider tow-hook, and installing about 25g (~1oz) of lead, CAing the hatch back in place, and covering the hatch with clear tape. The plane is currently balanced at about the mid-point of its recommended CG settings, which is great - I'll add a little noseweight next week for more stability and can still remove it for lighter handling.
I'd tested the motor, and at 50% throttle I could get 18 minutes out of the battery, so I set the timer to 12 minutes and settled for that.
So the plane now has 12 minutes and one flight on the clock. Fresh!
The full review is posted here: https://www.rcgroups.com/forums/show....php?t=1278650
Very gusty today. Quite a few planes came off the club field converted to packing foam or matchsticks. The 350 was a handful in gusts and turbulence due to the light wingloading. It managed to exit the flying field without any incidents, despite being blown inverted by a gust & rotor coming off a tree. I had a few people offer to help out when they saw it bouncing around out there. I could have taken their advice - I've only 4 hours experience - but the gusts were quite manageable when landing midfield (far away from any tree interference). Yet another reason I like a plane that's steerable on the ground - landing midfield isn't all that much of an issue.
Our club (WARS) uses a reclaimed garbage dump as a flying field. The council has turned it into parkland, but due to the nature of the underlying material, the ground is very bumpy. This makes landings (in particular) hazardous for any but the most robust aircraft, as a perfectly scale landing can come unstuck when an unexpected dip is encountered and the plane ramps off the other side, stalls, and noses in. As a result, I'm considering either converting this aircraft to floats and using it down at the river (which would be unfortunate), or converting the undercarriage to use 2" unfaired wheels with a taller ground clearance (which would spoil much of the scale appearance). The all-molded-glued-together construction of this plane really spoils the options here, because either direction will involve some rather messy surgery.
Last edited by Ben-M; Apr 18, 2011 at 06:35 PM.
Date - Minutes - Total HH:MM, #Flights
18/7/2010 - 12 - 00:12, 1
25/7/2010 - 12
25/7/2010 - 12 - 00:36, 3
1/8/2010 - 12
1/8/2010 - 12 - 01:00, 5
8/8/2010 - 8
8/8/2010 - 4
8/8/2010 - 13
8/8/2010 - 13 - 01:38, 9
14/8/2010 - 12
14/8/2010 - 12 - 02:02, 11
15/8/2010 - 12
15/8/2010 - 12 - 02:26, 13
21/8/2010 - 12
21/8/2010 - 12 - 02:50, 15
22/8/2010 - 12
22/8/2010 - 12 - 03:16, 17
29/8/2010 - 12
29/8/2010 - 12 - 03:40, 19
13/9/2010 - 12
13/9/2010 - 12 - 04:04, 21 (very gusty day @ ~20-25kts)
19/9/2010 - 12
19/9/2010 - 12 - 04:28, 23
26/9/2010 - 12
26/9/2010 - 12 - 4:52, 25
3/10/2010 - 12
3/10/2010 - 12 - 5:16, 27
17/10/2010 - 12
17/10/2010 - 12 - 5:40, 29 - And... CRASHED. Well, landed badly and damaged the nosewheel substantially.
22/5/2011 - 10+12 - 6:02, 31 - New nosewheel, at local park.
Plane cost $240
$/hr : $39
Last edited by Ben-M; May 22, 2011 at 11:27 PM.
Maiden Flight (edited)
Flying in calm air just before dawn. Probably my favourite RC flight so far. Oh for a nicer camera. The pods were some packing foam taped to the wing, the left one held the camera, the right one held some lead weight to balance the plane and create drag to keep it balanced aerodynamically (I could have just trimmed the plane out, but it would be much more speed sensitive then).
Last edited by Ben-M; Aug 08, 2010 at 07:56 AM.
The forecast for this weekend is calm winds - handy! I need practice landing the 350. I am having a lot of bouncy landings where I appear to stall/flare a little too high and the plane drops a little hard. I believe this is due to either or both of:
- Flaring / holding off too high, because I'm used to the wing height of my high-wing trainer.
- Substantial ground effect of the low wing causing the plane to float and for me to counteract this with a sharper decrease in throttle and/or up elevator in an attempt to slow it down.
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