Review of F20 Tigershark - Canterbury Sailplanes


By Steve Greenfield Riverside, CA October 9,2002

 

 

Introduction: While driving up the hot, dusty dirt road a couple of weeks ago to our local slope hill I was happy to see a large group of fliers. A local club was having a combat contest at our location. Every plane except one was a foam wing of some type. The different one I saw was a jet. Looping, rolling and briskly moving in and out of the combat wings.

The jet more than caught my attention. I remember my excitement at seeing Byron's Mig15 ducted fan about 18 years ago at his field in Iowa. I was hooked; the idea of a RC jet never left my mind. However, being the owner of a full size aircraft, I could never really justify the money for a ducted fan model, let alone the thousands of dollars for a turbine fire breather.

Back to the present. I watched the slope F20 fly for awhile and then after he landed, struck up a conversation with the pilot. Let's just say he was not one of those real helpful people, and just brushed me off saying it was scratch built, and no I couldn't copy it. So… that made me want one even more.

I thought for a brief second about scratch building one, but I do not have the scratch building DNA in my genetic code. I'm lucky to get a kit to look and fly right. Off to the Internet…. I finally found what I was looking for from Canterbury Sailplanes in New Zealand. The price was right and it was EPP, thus satisfying my need for lightweight, low cost and durability.

Building: I received the kit in a reasonable amount of time considering it came halfway around the globe. Right off the bat I was pleasantly surprised by the simplicity of the kit and the well-done instruction manual with excellent photos. Included was the glue, a roll or red covering tape, and a roll of the stickiest bi-directional filament packing tape I've ever seen!

The plane was quite easy to assemble, and even though I am not a sculptor, I was able to get a reasonably close looking jet shape from the fuselage in a short amount of time. The wing was easy as well. It required no sanding, and the fiberglass spars were easy to glue into the pre-cut spar slots.

Good planning as to the radio cutouts. I opted to use Hitec radio gear. I used a standard HS81 in the elevator position. Since the aileron servo is hidden permanently inside the body, I went for the HS81MG (metal gear) with the much stronger DuBro servo arm. I used the Hitec555 receiver and a 270ma battery pack. I also decided to mount the switch on a piece of 1/16th plywood recessed into the side.

Everything so far had taken the amount of time indicated in the instructions. I did decide to try to make this one look good. Our club has a contest for the best looking new plane and I wanted to win. Plus, I really love the red and white color scheme. I took a LOT of time on the fuse carefully taping the body with the fiber tape, making sure there were no wrinkles. I then applied the red tape to the fuse with great care (and a large number of tape pieces). I applied the white trim (Ultracote Plus) after laying them out on paper. I used 3M77 and applied the trim patterns to poster board and cut them out to make templates.

I badly wanted the F20 logo and numbers, so I bought some clear ink jet Avery label sheets (the full-sheet version) and printed the logo on that sheet. The large F20 I cut out of the white Ultracote. That all sounds easy… but it took a long time.

I followed some good advice, and after placing the fiber tape on the wing, I coated the wing with Weldwood Contact Cement. In my experience here in Southern California, the 3M77 tends to release its hold as the temperature goes up. We often fly at 100 degrees plus, so I didn't want saggy covering this time. I covered the wing with the standard Ultracote, and it went on well. It is really stuck there!! I did the ailerons in Ultracote as well.

For the attachment of the ailerons I split a length of the 2" fiber tape by laying it on wax paper and using a X-Acto knife lengthwise with a metal ruler. This is the technique the local combat guys use, and they swear it is the only technique that holds.

I took a good amount of time measuring the proper wing attachment position. This is one area the manual could be a little more specific for beginners. I measured from the rear corner of the wingtips (using a metal rule) to the back of the tail where it joins the body, making sure they were equal. I checked the leading edges to make sure they were the same length and confirmed the same with the trailing edge.

Before I attached the wing, I was careful to follow the recommendation about the 2mm reflex in the aileron position. Also, I made sure control rods and all wires are free and clear inside.

The wing is glued on using the marvelous Bostik Clear Bond glue. I have not seen this in the US. It smells like old-fashioned plastic airplane glue, and appears to bond quite well. The rudder is virtually impossible to install crooked, the same with the elevator. Still, it might be helpful to mention to beginners the use of a plastic triangle to confirm the 90-degree angle.

I let it sit overnight, and then did final setup on the radio. Following instructions as close as possible I set the throws and end points, and decided for a little better initial control to use some exponential in the radio.

Wow… it was finally done; just a little bit of balance weight in the nose and it was good to go.

Just to give you an idea, I started this kit on a Thursday evening and took it the club meeting finished 5 days later (working each evening and afternoons on the weekend). It was depressing for me to see a very nice fiberglass and sheeted wing P80 slope plane at the meeting as I was hoping to win the prize. Well, as it turns out the builders left the room and when we came back the vote was in favor of the F20. There were 15 members, and I unashamedly encouraged my wife to vote in my favor. She said it was 14 for the F20 and 1 for the F80. Other models weren't considered. Yeah !!

Flying: OK, it is now the day after the meeting (which is today as I am writing this) I took the F20 out to the slope and there were several people already flying. Darn it, I wanted to be alone "just in case". Regardless, they were there and also had video cameras. Now the pressure was really on.

I stepped up to the edge of the slope. The wing was light, around 8+ MPH. Being a nervous type I decided to add two clicks of up elevator so I wouldn't dork it into the side of the hill on launch.

Now I've read about his before, but it has never happened to me. I have read often of somebody saying the plane "flew as if it were on rails" first flight. My past experience has been more like grabbing for the sticks in sheer terror right after launch. This was different. I launched into the wind and it just flew straight forward and had a very slight climb. Considering the wind was so light I tried a few shallow turns, the plane tracked straight and true. Keeping the first flight conservative I came in for a landing. Positioned it in the wind about 10 feet high, rocked the wings from side to side with a touch of down, and it settled in gently.

I waited until the wind picked up a little, and then flew again. This time I tried rolls, they came out nice and even both directions. Loops worked well with gentle backpressure and good speed. Then it was time to try the Split S, inverted flight, it did it all easily. This plane really builds speed fast in a down attitude. It is so cool to see that climbing banked attitude and have it look like a real jet. As a matter of fact at a distance it looked just like the expensive ducted fans and turbines at a small fraction of the cost. And….NO fuel cost ever !!!

The fellow with the glass F80 came out, and couldn't get enough wind for it to fly. He broke a 2" hole in the fiberglass fuse on his 3rd try. The F20 didn't even have a scratch after a total of about 30 minutes flying.

Conclusion: This is a superb kit. I am planning to build another with the idea of making it a daily flyer. Probably single color with some trim and that will be it. I bet I can build one in 3 evenings. That will be the one I take chances with and possible do some combat as well.

It is my opinion it can be built and flown by a first-time builder. I would like to see the measurements in inches as well as the metric. It would be nice to get the patterns for the trim, as well as sanding patterns for the canopy, fuselage, and canopy covering. Perhaps that is something Canterbury could put on their website as pdf files. I always find it difficult to picture canopy covering in two dimensions and then have it work in three.

I'd also like to see Canterbury offer the bi-directional tape and Bostik for sale.

Bottom line… impressive easy-to-build kit, impressive flyer and hats off to Canterbury Sailplanes for creating such a great value! Go buy one now, you can have it flying next week.

 

Epilogue: The above experience and the many great subsequent flights are what caused me to contact Canterbury Sailplanes and become the US distributor. I did build a 2nd F20, and that is the one you see Dave with on the front page. We had a ball flying that day, and I'm sure you'll have as much fun! Since that time I've flown the F20 (with 8 oz ballast) in a 50 MPH Santa Ana wind. the plane penetrated the wind when no other foamie would, and was fully aerobatic, with huge loops, rolls while standing still in the wind, inverted flight , everything !! What a blast.