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Pumpkin drop event

A less than successful Sportsman S+ maiden flight

#1
Greetings,

As I review and edit, I realized that this is also a review of the Sportsman S+. I encourage all who read this to respond with helpful suggestions and if I made mistakes, correction. I further encourage Horizon Hobby to respond (hello Mike), as I would enjoy their feedback. I greatly enjoy building and flying RC planes (and multirotors, but that is a whole other subject) and want to be the best pilot I can be.

As I am new to flying RC planes, I thought it advantageous to supplement my time on RealFlight, my Flite Test-based planes, and buddy boxing with some very experienced pilots in my RC club with the Sportsman S+.

The first flight experience was very, very disappointing.

I carefully went through the compass calibration set-up procedure outlined in the manual three times over the week before yesterday's first flight. One critical oversight on HH's part is not providing visual or auditory verification that the procedure was performed or completed correctly. The same expressly applies to setting the virtual fence: airfield. This lack of verification is just lazy design and engineering, not doing the right thing that ensures a great customer/pilot experience.

At the field, I powered the DX5 transmitter (yes, I bought the RFT because my DX6i cannot be made to take advantage of all of the S+'s functionality), then powered the plane, closed the battery compartment, righted the vehicle, and placed it on the edge of the runway perpendicular to its long axis. I then waited for the auditory GPS-link conformation tones. Once sounded, I picked up the plane and moved it to the centerline on the runway, pointed into the wind, and ran the throttle to full and back down to minimum (hopefully setting the takeoff/landing direction into memory). I then walked back to the edge of the runway, throttled up, and took off. (The runway runs from east to west, with the wind coming out of the west yesterday [as it does about 360 days a year].)

With the guidance of one of the experienced pilots, I did a couple of the simplest circuits possible around the field (big rectangles; during which I noticed strange VF behavior I will cover below). After completing these and headed into the wind west of the runway, I wanted to get the plane down safely, so I pressed the HP/AL button for the required three seconds, at which point the plane reacted and bank right to go downwind to the east end of the runway. It did go past the east end of the runway, banked right again while descending, and appeared to line up well with the runway (it seemed to duplicate the same position that I observed the experienced pilots using when landing their planes). However, this is where things started going very wrong. Instead of continuing straight down the runway and continuing its decent to land, it took a vector that sent it across the runway from left to right. When it passed me (I was to the left of the runway's mid-length [where the throttle was taken to full as described above], the plane was still about ten to fifteen feet above the ground. It end up smashing into a wire fence that is about twenty feet off the right side of the runway, opposite the pit area. This put two nasty divots in the wing and a large area of wrinkles in the fuselage's foam ahead of the wing's leading edge (caused by the wings twisting on impact).

With that unpleasant, disappointing, and frustrating experience, I picked up the plane, dusted off the dirt and weed fragments, repositioned the wing, and put it away. I went back to buddy-boxing with the experienced pilots that have adopting me as their student pilot.

Right now, I am seriously considering that instead of learning to fly on the $300+ Sportsman with its $38 dollar wing and $38 fuselage, I'll go back to building the Flite Test Tiny Trainer, Storch, and other FT planes and learn to fly with these. Even a catastrophic crash with one of these planes that results in a total loss of the entire airframe is only a $4 to $10 incident.

I do see myself flying the Sportsman in the future, but not relying on the GPS-based features. With my experience, and based on the similar comments of others and what has been observed in some videos on YT, it seems that the S+ features are not ready for public consumption.

The VF airfield did not function correctly. When banking around to come over the runway at the downwind (east) end, the plane would react to the VF (at a point that seemed to be near, but not at, the edge of the runway where GPS lock was made) and go into the holding pattern. Yet when flying to the west end of the runway and turning left, clearly going past the runway edge and toward the pits, the plane did not react with going into the holding pattern. Extremely inconsistent. And frustrating, since it left me wondering if I had indeed correctly setup everything properly before the flight.

And there are errors in the manual. One is the compass calibration. It instructs the pilot to power the receiver and then later to power the transmitter (steps 1 and 2 on page 15). This is just plain wrong. This is at least corrected on Mike's video that covers the calibration process. And there is no mention in the manual that the rate switch (at least) must be in the 100% position when using the sticks to set a function (the lower rate does not produce a count that is high enough for the receiver to recognize as a function select).

Overall, it seems that the plane was rush to release. Instead, another three to six months should have been spent refining the receiver's and GPS module's software. Additionally, visual indicators should be been designed and engineered to verify to the pilot that compass calibration and VF were performed and set correctly. Another DVT or PVT pre-production phase would have produced a more robust and user-friendly solution.

Thanks.
 

quorneng

Well-known member
#2
Sorry to read about your problem but I do wonder if your expectations are too high.
I know the marketing hype says the Sportsman S+ can be landed with no pilot input however it would seem to me unwise to completely rely on it to do so given the fact that it uses 'cheap and cheerful' electronics.
If you want absolute reliability in an auto land system you are likely to have to pay a great deal more to achieve it.

The old adage in RC flying is "If you cant afford to loose it - don't fly it" so on this basis your suggestion to learn to fly (and suffer the inevitable crashes) on simple planes is a sound strategy.
 
#3
Marketing material doesnt really say it can auto land either, at least on the website it says "AutoLand actively assists with landing with minimal to no pilot input". Did you try to correct its trajectory upon landing?

That said, Im going to agree with quorneng; all these GPS features are neat in theory, but you'd be very unwise to rely on them. Especially for landing. Without airspeed sensor and sonar, no autopilot can be trusted to land properly (wind and air pressure can and do change).
Im flying a pixhawk enabled plane with all the bells and whistles, telemetry radio, dual compass, airspeed sensor etc. The electronics may cost as much as your RTF kit. But when its time to land, I always put it in manual. Its nice to know it might autoland successfully in case my transmitter dies or I pass out or something, but thats about where my confidence ends.

I do agree with your other criticism though, like lack of audio or visual feedback and at least geofencing ought to work. Still, if you thought this plane would eliminate the need for training, then you probably wasted some money. On the bright side, its probably still an excellent (if slightly expensive) trainer when paired with a human instructor :)
 

makattack

Winter is coming
Moderator
Mentor
#4
Yah, I have the same problem ZoomNBoom and quorneng mentioned in their posts. This over reliance on automated features from RTF models is a bit misleading. A pilot should never rely on what could be a potentially unreliable GPS signal and should really only rely on these features as "last resort" safety modes or be fully prepared to switch to a manual flight mode in order to recover from issues with automated control.

I've had both great success and failure with these features on APM -- a lot of it can be attributed to pilot error (forgetting to remove a pitot tube cover, not isolating all vibrations, etc), so I've learned to just not overly rely on them. Heck, I built my VersaWing with APM so that I could use it as a "trainer" without a buddybox cord. I wanted to use the geo-fence, altitude limiting, etc features... but ultimately, I don't trust them all enough to actually hand the TX to a new pilot without a buddy cord attached.