UDI U-841-1

Quadcopter No. 16 is second one by UDI

     The UDI U-841-1 is the sixteenth micro quadcopter in my fleet.  It was purchased January 22, 2017, the day after I got the Zoopa Riot.  The U-841-1 came from Micro Center in Sharonville, Ohio, the fourth drone from there.  It cost $39.99.  It has made 11 flights so far, all indoors.

UDI U-841-1

     This drone has a unique feature that sets it apart from all the other quads in the fleet: wheels.  A set of four wheels, as shown in the photo above, can be attached to the quad allowing it to be driven like a car.  There is also a set of two large wheels that can be attached using a long axle that snaps onto the top of the drone running from side to side.  There is a ground mode on the controller which prevents the "car" from taking flight when the throttle is increased.  In normal flight mode the "car" will take off and fly like any other drone.  A set of prop guards is also provided for use during normal flight when the wheels are not used.
      I found the drone to be a good flier, similar to the UDI U-27.  In fact, the batteries and the controller are interchangeable.  However, I did not like either set of wheels.  It was hard to steer the vehicle in both cases, and after one run of each, I have not tried them again.
     The fact that the controllers for the U-27 and the U-841-1 are interchangeable came in very handy when I brought this quad home; the new controller for the U-841-1 did not work.  The power indicator light did not come on and the unit would not bind to the drone.  I tried the U-27 controller and it worked just fine for all the features.  So, I decided to keep the drone and try to fix the controller if I could, knowing that I had another controller that would work with it.
     I removed all of the necessary screws, opened the case, unplugged one connector, made a visual check for loose wires, and then, set to work with my Radio Shack multimeter.

Circuit board inside of U-841-1 controller

Control switches in U-841-1

     After a few minutes, I found that no current was getting out of the battery holder.  Then, I observed a small gap between two contact plates near where the power distribution wires attached.  I used a flat screw driver to slightly bend one plate so contact was made.  That solved the problem and the controller works fine.  I now have two interchangeable controllers.
     I wonder what others do when they get an inexpensive drone that doesn't work because of a small, correctable problem.  They could write one-star reviews on Amazon saying how their grandson's Christmas was ruined.  They could take it or mail it back to where it was purchased and ask for a replacement or refund.  But, how many would try to fix it?

Zoopa Q165 Riot

No. 15 Joins the Fleet

     The latest drone to see action in the flight room is the Zoopa Q165 Riot from ACME the game company.  It was purchased on January 21, 2017, at Staples in Mason, Ohio, from the clearance shelf for $49.50.  The Zoopa Riot had been at $69.95 a few weeks earlier, which I thought was a bit too pricey.

Zoopa Q165 Riot

     ACME is a German company, located in Delbruck, Germany, but the Zoopa was still manufactured in China like all of my other drones.  I have flown it 11 times, all in the flight room.  It is a great quadcopter with very smooth handling.  It is one of a few that I can handle on high speed indoors.  This quadcopter has an interesting flip mode, triggered by a small orange button on the upper right side.  The instruction manual says to press and hold the flip button and then move the right stick up and release it immediately.  I have found that you only have to press the flip button and then you can release it and the next time you move the stick it will flip.  In fact, if you hold the flip button down and hold the stick forward the Zoopa Riot will do continuous flips until you release the button or stick!  This is one of a very few micro quadcopters that will do continuous flips.  I eagerly await warmer weather so I can try the continuous flips outdoors.
      The Zoopa seems to benefit from "German engineering".  It looks nice, handles great and seems to be fairly rugged.  Although, I have already cracked one of the prop guard rings and had to patch it with duct tape.

The Micro Quadcopter 500

500 Flights in 198 Days

     I keep a log of every flight that I make with my quadcopters, so I knew that on February 2, 2017, I had made my 500th flight.  I made my first flight with my first micro quadcopter, the Hubsan X4 H107L, on July 20, 2016.  Thus, it took me 198 days to achieve 500 flights; an average of 2.53 flights a day.  Of course, a lot of days, I didn't have a chance to fly any of my fleet, but, on the other hand, my one day record was 11 flights.  As a retired engineer, I enjoy keeping records and analyzing data.  I have put together the following table showing all of my drones, the number of flights for each, how many days since I purchased each one and the average number of days between flights for each drone.

Drone                          No. of Flights             Days since purchase       Days between flights

Spidex                                88                                  184                                  2.1

Hubsan                               64                                  198                                  3.1

Verso                                  52                                  196                                  3.8

Syma X13                          44                                  168                                  3.8

UDI-U27                            40                                  168                                  4.2

Spyder X                            36                                  158                                  4.4

Blade Nano                        30                                  191                                  6.4

Kodo                                  23                                  181                                  7.9

Sharper Image DX2             24                                  135                                  5.6

Proto Z                               22                                  170                                  7.7

Quadrone                            22                                 143                                   6.5

Sky Rover                          13                                   63                                   4.8

Sky Thunder                       12                                   63                                   5.3

Swift Stream                        9                                    44                                   4.9

UDI U-841-1                        6                                    12                                   2.0

Zoopa Riot                           6                                    13                                   2.2

Quadrone Spark                   5                                    12                                   2.4

Quadrone Sparrow               4                                    12                                   3.0

     The last four quadcopters have not been discussed in their own post, yet, since I am waiting to get more flights with each one to have a better understanding of their capabilities.  In the chart above, the "Days between flights" column gives a fairly accurate indication of which drones are my favorites.

The Flight Room Becomes a Race Course

Results of a few time trials

     After flying all my drones back and forth the length of the flight room for a few months, I decided I needed more of a challenge: like a race course.  After some thought, I decided to use crepe paper streamers to make gates to fly around and through.  I took two eight-foot long pieces of paper, one blue and one orange, twisted them together and duct taped them to the ceiling and floor.  I put four of them in a row across the 12-foot width of the room, thus making three gates each four-foot wide.  I made three rows of gates, with rows being ten feet apart.  I now had a slalom course with nine gates that I could fly through using a variety of different patterns.

Slalom Course looking North

Slalom Course looking South

     I started out with the simplest course: a rectangle.  Fly down the three gates on the left side, across the back and up through the three gates on the right.  I wanted some quantitative measure of how well I could fly each of my quads on the course, so I decided to time each one in a three lap race around the course.  I would start the stop watch on my wristwatch, take off from the launch pad on the floor, fly the three laps, land (or crash) into a bean bag landing zone and stop the clock.
     I soon learned that flying this course was not easy!  Part of the problem was my lack of experience and skill and partly the narrow size of the gates for the speed and quickness of some of the drones.  A major problem was misjudging the speed of the quad and the distance to the back wall.  Luckily, the walls are padded.  I also chewed up plenty of streamers with the props.  Using the slowest speed settings for each drone, I have completed the course 41 times.  The best time was with my Syma D44: 37.06 seconds.  Here is a list of the number of times I finished the course (three laps) for each drone and the best time for each:

Quadcopter                   Completions      Best Time (seconds)

Syma D44                              3                    37.06
Ares Spidex                           4                    37.36
Sky Rover                              2                    38.44
Propel Spyder X                    5                    38.68
Swift Stream                          5                    39.89
Syma X13                              5                    44.45
Quadrone                               2                    46.63
Dromida Verso                       1                    52.89
Hubsan H107L                      6                     53.37
Dromida Kodo                       1                     54.37
Blade Nano                            1                     59.90
Sharper Image DX2               2                     63.32
UDI U-27                               2                     64.49
Estes Proto Z                          2                     67.32

     As can be seen from the results, there was quite a range of times over the entire fleet.  I was able to get each one of my quads through the course at least once, but is was a challenge for a few.  The best times, I feel, represent the quads that are the easiest for me to control and not necessarily the fastest ones.  My Blade Nano is certainly the fastest drone in the fleet, but I just couldn't control it well enough on this tight course to get a good time.  The Propel Spyder X set the record by having  completed the course all of its five times on the same battery charge.
     After a few days, I scrapped the slalom course, afraid I was going to do some major damage to a few of my drones.  I then built a simple oval race course with a large pylon at each end of the flight room.  Each pylon consisted of four two-stranded, twisted streamers attached to a paper plate at each end and tacked to the ceiling and taped to the floor.     

Two Pylon Race Course

Close-up View of  a Pylon

     Again, I timed three laps around the course for each quad.  The times dropped significantly for this new arrangement.  With a total of 90 course completions the results were:

Quad                               Completions      Best Time (seconds)

Quadrone Sparrow                  6                        25.81
Zoopa Riot                              5                        26.09
Propel Spyder X                     17                       27.07
Dromida Verso                         7                       27.53
Blade Nano                              6                       27.70
Dromida Kodo                         6                       28.48
Hubsan H107L                         6                      28.98
Swift Stream                            6                       29.21
Syma D44                                7                       29.27

Ares Spidex                            15                       30.24
Sky Rover                                3                        32.20
UDI U-841-1                            1                       35.95

Quadrone                                  2                       36.54
Syma X-13                                1                      37.87
Sharper Image DX-2                 1                      38.03
UDI U-27                                  1                      41.44

     You will notice that a few new names appear on this course due to some new purchases.  I could not get the Proto Z or the Quadrone Spark around the course to the finish, although, I tried.  As before, I am sure that the times reflect my flying ability more than they do the quads' speeds.  This course was much easier than the previous one and I enjoyed it a lot more.

Sharper Image DX-2 goes to the Repair Shop

A little solder fixes the problem

     While flying my Sharper Image DX-2, it crashed into a pylon on the race course in the flight room.  I will talk about the race course in an up-coming post.  Usually, hitting a pylon is not dangerous since they are made of crepe paper streamers.  Whenever I hit one, I immediately shut down the throttle to avoid having the props cut the paper or getting the paper wound tightly around the prop and its shaft.  Most often the quad gets tangled in the streamers and stays suspended until I retrieve it, or, it falls harmlessly to the carpet.  

The race course pylons

     This time the DX-2 fell to the floor.  When I put it back on the launch pad everything appeared fine.  But, when I increased the throttle it immediately rolled over, not once, but a couple of times.  I inspected the propellers while slowly increasing throttle and discovered that one motor was not turning.  So, after removing 12 tiny screws, popping off the props and prop guards and separating the upper and lower sections of the quad, the problem was immediately apparent: a motor wire had a broken solder connection.  The only previous time that I had damage to a motor was with the Blade Nano when the motor cap pulled off and I had to replace the whole motor; but it just plugged in.

The DX-2 disassembled

     I got my soldering tools out and in a matter of minutes had the wire reattached.  I plugged the battery in, turned on the quad and the controller and carefully gave it a little throttle.  The motor spun perfectly.  But, another one of the motors would not spin.  I soon found that I had accidentally broken another connection.  A bit more soldering and that one was also fixed.  Reassembly and then back to the flight room to finish the flight and try to avoid the pylons.

     While I had the quad apart, I discovered that the battery could easily be replaced by soldering if and when the battery ever died. 

Swift Stream Z-32CV Camera Drone

Drone #14: Swift Stream Z-32CV

     My fourteenth micro quadcopter is the Swift Stream Z-32CV.  It was purchased at CVS / pharmacy in Maineville, Ohio, on December 21, 2016, for $29.99.  The Swift Stream is larger than any other of my drones.  At 120 mm diagonally from propeller center to center, it is over my intended limit of 115 mm, but, at this price and with a camera, I could not pass it up.  My next largest drone is the Dromida Verso at 112 mm.

Swift Stream Z-32CV Camera Drone

     I have made six flights with the Z-32CV in the flight room.  It handles very nicely and I cannot wait to get it outdoors and see what it can really do.  The quad has very long landing gears which give me some problems.  If it just grazes the carpeting while flying horizontally, the landing gears will catch and flip the drone over.  And, when landing, it has to come straight down with no horizontal component to avoid flipping.  Except for this, it is great fun to fly.
     With this post, I have completed introducing my entire fleet of fourteen micro quadcopter drones.  I think it is quite a diverse group with plenty of variations and different options.  But, it is time for me to think about expanding the fleet for there are plenty of quads on the market with all new features just waiting for me to try.  So, I am asking my reader(s?) to suggest new drones, similar to the ones I now have, that I might invest in.  My only requirements are:

     1. They have to be QUADcopters - four propellers only.
     2. They use 1S LiPo batteries.
     3. They measure approximately 100 mm (4 inches) diagonally across the propellers center to center (85 - 115 mm, 3.5 to 4.5").
     4. They cost less than about $50.  More, if they have some great new unique feature.
     5. No FPV, yet.

     So far, all of my drone purchases have been from local merchants, but I am running out of sources for new ones that meet my criteria and will have to eventually go online for additions to the fleet.  Amazon, here I come.

Syma Sky Thunder D44 Dragonfly Drone

Lucky No. 13 of the Fleet

The Syma Sky Thunder D44 Dragonfly Drone has the longest name of any of my drones.  I acquired it on December 2, 2016, from Meijer in Loveland, Ohio, for $39.99.  I have flown it nine times, all in the flight room.

Syma Sky Thunder D44 Dragonfly

     The D44 is a fun micro quadcopter, although, it does not have any unique features that my other drones don't already have.  It combines easy control with fairly fast flight.  When I set up a slalom course in the flight room and flew each drone around it, the Sky Thunder had the fastest time of all.  Again, that does not mean it is the fastest drone I have, but rather the one that I personally can control best at high speeds.  And, its margin of victory was very slim.  I will give a more detailed description of the race course and flight results for each quadcopter in a future post.
     Like my other Syma drone, the X13, the D44 has geared props.  In addition, the motors on the Dragonfly are horizontal with the motor shafts perpendicular to the propeller shafts.