Icare Sailfish F3K 900mm
This small discus-launched glider is perfect for catching thermals!
This small discuslaunched glider is perfect for catching thermals!
I love gliders! I got my start in RC flying gliders, and I have an array of gliders on shelves in my garage that I fly on and off throughout the year, including high-start and winch-launched gliders, scale sailplanes for aerotowing, and even motor gliders. What I don’t (or didn’t) have is a discus-launched glider (DLG). And then along came the opportunity to review the Sailfish 900mm DLG from Icare-icarus in Quebec, Canada.
The Sailfish is available as either a kit or a plug-and-fly (PNF) version. The latter is fully built and includes the servos and pushrods installed and adjusted, a receiver Lipo battery, and a USB battery charger. You add a micro receiver and then go fly. I was given the choice and decided to build the kit. No need to adjust your glasses; I learned to fly when there were only two choices: build your own kit or pay someone to do so, and the lawn-mowing money only went so far. I was thrilled to receive the kit version and see how glider kits had changed over the years. I opted for the battery and servos that they use with the PNF because I know they fit, and I ordered a micro receiver.
The Sailfish uses a simple 2-channel system consisting of just rudder and elevator controls. The Sailfish can be built by anyone that has ever built or repaired a wood model and can be flown by those with minimal flight experience; it is, however, a relaxing everyday flier even for more experienced pilots.
The Sailfish is a discus-launched (or DLG) F3K glider. The name is derived from the sport of discus throwing, and to launch the plane, you hold a peg on the wingtip and use the rotation of your body and arm to throw the glider as high as you can. I’ve seen accomplished DLG competition pilots hurl the larger 1.5m DLGS as high as 300 or 400 feet!
The first unique feature of the Sailfish is the lack of an instruction manual. I’ve seen this before, and I wonder if it will be a trend. You assemble the Sailfish after watching a five-part video series on Youtube. Each video is approximately 30 minutes long and covers a major assembly step. There are no voice instructions in the videos, they are set to relaxing music and the information is presented in a completely visual yet effective format. I found myself in the shop with my ipad, watching the full video through once, then starting over and completing each step while pausing the video between steps.
Other than the radio equipment, the kit comes with everything you need, including covering material and even a bottle of glue.
The Sailfish uses a carefully considered combination of materials so that it is both as light as possible yet strong enough to survive the rigors of many repeated and often violent discus launches. The wing is constructed out of balsa-wood ribs with carbon-fiber spars as well as carbon leading and trailing edges, and built over a provided wing jig. Wood gussets and carbon-fiber parts in all the right places ensure a sturdy assembly with a minimum of weight. Despite being a kit, there is a jig provided to build the wing, and since the Sailfish lacks ailerons and spoilers, the wing construction is quite simple.
The fuselage consists of a carbon rod that extends from the fiberglass pod and holds the tail feathers in place. A minimum amount of room is provided that is just enough to hold the two sub-micro servos, a small receiver, and a Lipo flight battery.
The tail feathers are made out of balsawood slab, and the rudder and elevator are hinged with the provided heat-shrink covering material. I would love to say that I changed the covering to white on the elevator because it looks better, but the truth is I had my iron too hot and mangled the first piece of covering.
Since every gram matters, there are no markings to apply. When completed, the transparent yellow covering looks great. Just be careful not to make a mess because the translucent covering will show any mistakes you make.
IN THE AIR
A national champion sailplane pilot once told me, “If you want to learn how to read the air and work minimal lift, get yourself a DLG and practice, practice, practice!” I never fully appreciated that until I spent the better part of a day flying the Sailfish. Finding a thermal and harnessing nature to climb and extend a flight is something that never loses its thrill. While it
took me several tries of launching and walking, I slowly refined my technique to maximize my launches and then to find lift and stay up for increasingly longer flights.
All of a sudden, on one of my launches, I noticed that I wasn’t coming down for several minutes and, in fact, had caught a baby thermal forming at ground level. Thermals are like bubbles in a fish tank: They start small at the bottom and expand as they rise and the air pressure lowers—meaning that at ground level, the area of lift is at its smallest and most difficult to hook. Rising columns of bugs or circling birds often indicate the presence of a thermal, but the truly gifted sailplane pilots have an uncanny sense of when a thermal is going to form and are able to throw their DLG straight into lift.
GENERAL FLIGHT PERFORMANCE
Stability: The Sailfish is extremely light, and while the design is stable in dead air, the 125g glider doesn’t hold its own well when the wind picks up. Tracking: While lack of ailerons will take some getting used to by those unfamiliar with flying rudder only, the Sailfish tracks well and goes where you point it. Aerobatics: The Sailfish isn’t designed for aerobatics, and the lack of ailerons limits what it can do. That said, I tried a few flights doing several loops and even a barrel roll or two using full rudder and up-elevator. While aerobatics aren’t its intended purpose, flying the Sailfish doesn’t have be boring either. Glide and stall performance: The miniscule wing loading makes the Sailfish nearly impossible to stall, and when it does, the nose drops and it keeps flying. Gliding is where the Sailfish excels, and with some practice, I was hitting flights of 10 minutes and more.
While a 2-channel glider doesn’t need much in the way of fancy programming, I did set up my Spektrum DX9 to control the rudder with both the aileron and the rudder stick. I also set up a rudder offset because my throwing motion was pulling the Sailfish to the left each launch. The rudder mix gave me some right rudder on a switch during launch, and with a little tinkering, I was making nice straight launches.
Left: An easy-to-use jig is included to ensure that the ribs are both square to the spar and perfectly spaced out.
Above: The solid pieces are laminated on either side of the cutout piece and form a strong but light mount for the horizontal stabilizer.
The stabilizer and elevator are simple slab components with a carbon-reinforcement rod embedded in the stabilizer. There are no hinges as the elevator is hinged by the covering material.
The compact size of the Sailfish makes it easy to bring to the field no matter what else I am flying. The translucent covering looks spectacular on sunny days and is visible when it’s overcast.
I installed the carbonfiber control horns with Zap gel after I removed the covering from the gluing area using an old soldering iron.
Above: The carbon-fiber tail boom is slotted on this side for the rudder pushrod. The whole assembly is rigid when all the components have been installed. Left: The covering material arrived in sheets that were sized with enough overlap to do a proper...