Thursday, April 2, 2015

HobbyZone Sport Cub S Review

The reason

Yup, this one is weird. The wings don't move! Not something I usually do. However, I like scale aircraft, and those aren't very popular for helicopters, at least not compared to aircraft. So scale copters are rare, and hobby grade ones tend to be expensive. I can find a number of airplanes I'd like to fly that cost less than a simple pod-and-boom helicopter of similar quality, never mind the cost of putting a scale fuselage on it!
So I bought this to learn to fly fixed wing, as that's what it was intended for. I also picked up a pair of floats for it, because - well, they were nearly free and look very cool, which is the point!

The aircraft

The Sport Cub S is an ultra-micro scale model of the Cub Crafters Sport Cub, which is a variant of the legendary Piper Cub. At that scale, it's missing most of the struts, and there's no cockpit detail, but it's about as close as similarly priced toy grade helicopters - and it's hobby grade. In particular, it has a steerable tail wheel, which is a nice touch in a an inexpensive model.


Here you can see it sitting on a Devo 6S to prop it up so you can see the underside, and to provide some scale. The ugly white line on the nose in front of the canopy is excess glue from one of my repairs. You can also see some dings in the wings and floats.

UMX Sport Cub S on a Devo 6S


Unlike rotary wing devices, the airframe is made of a modern styrofoam. This is easy to shape, and looks a lot better than it sounds. It's also very light - the all up weight is less than two ounces. It is very durable, which is a great feature in a beginner aircraft. I've crashed it numerous times, and most of them resulted in little more than a ding or dent. A couple of times the foam cracked seriously, but little water and gorilla glue put it back together, if not quite as pretty.

The S variant comes with the E-Flite SAFE flight control software. This is similar to the same system on the 200SRX, the 200QX, and the 350QX. There's a Beginner mode that limits the flight envelope and auto-levels, an Intermediate mode that doesn't auto-level but still limits the flight envelope, and an Expert mode that doesn't limit the flight envelope. On all the 'copters, the Intermediate mode auto-levels. I think the Sport Cub variant is more useful - I actually use the beginner mode on it! I think that having a mode with limited envelope but no auto-leveling is more useful than two different limits on the envelope with auto-leveling. The SAFE system also includes Panic button, which puts the aircraft upright and level no matter what you're doing.

The floats

The floats are actually for the UMX Carbon Cub SS, but the Sport Cub was designed so they would fit. Installing them, or switching back to the standard landing gear, is straightforward. Two screws and a small plate hold in each of the gear struts, and floats use those, plus an identical set for the rear struts. The extra hardware comes with the floats, as well as a plastic tab for the rear that needs to be glued to the frame. After that. just unscrew the appropriate set of screws, pop what they were holding in out, plug in what you want in, and then put back the appropriate screws.

I haven't tried them on water yet - I'm still a little leery of that. However, they were reported as working on snow, and I had a couple of chances to try that as well. Taking off and landing on snow on the floats is easier than doing the same on concrete with the wheels - at least on my driveway, which is a bit rough. And it does look really nice in the air with the floats installed.

The flying

My first flight was a disappointment. I had spent a fair amount of time flying in a simulator, practicing bank and yank flying. This is a beginner technique, but SAFE's auto-leveling makes it ineffective. The bank to set the aircraft up to turn was leveled out by SAFE before the yank would turn it, leaving me with no feeling of control and an aircraft crashing in the woods far downwind of my flying field.
I recovered the aircraft, and as I indicated, the damage was limited to a few dings in the foam. So - after giving the weather a while to settle down - I gave it another try.
The second flight went much better. I forgot what I'd learned in the simulator, and treated it like a helicopter or multirotor in forward flight. That actually did what I expected it to, and the SAFE took care of keeping it level.
The rudder trim on the aircraft is a U in the rudder servo line that you pinch and expand. It works well in practice, but I worry about how well it will survive if I have to do that often. I may need to start making fine adjustments with the controller, not the wire. The SAFE system in beginner mode deals with the other trim issues, which is a major benefit!
Switching into intermediate mode to turn off the auto-leveling, it's obvious that moving the little 1S lipo back and forward in the battery compartment moves the CG significantly, and some care needs to be taken with that. However, once that's done, it's a nice stable aircraft, even in a stiff wind. I don't use the Panic button in this mode, as just switching back to beginner mode works fine.
Finally, turning off the flight envelope limits by switching to expert mode lets you do some aerobatics. Loops and rolls are fine. This is not really my thing even with aircraft I'm more familiar with, so I didn't go near the limits of the aircraft. It's not a jet or a 3d flyer, so probably isn't all that exciting if that's what you're looking for. I believe the Panic switch prevented more than one crash in this mode.
I get 6+ minute flights on my throttle-controlled flight timer, but being in Oklahoma spend a lot of time just gliding into the wind.

Summary

I like this, and think it's a lot of fun. The SAFE system deals with a lot of things that would trip up a beginner who doesn't have an experienced flyer helping. I think E-Flite's claims of learning to fly by yourself aren't at all unreasonable.
As a final note, unless something unexpected turns up, my next aircraft purchase is liable to be fixed wing again. Possibly a glider, given the wind conditions here. I still own some aircraft I haven't reviewed yet, so those may show up first.