Every now and then a RTF comes along and just cry's out to go faster. As soon as I saw the F-27 Stryker by Parkzone out of the box, I had visions of brushless motors, smooth mirror like surface and even a ducted fan. I wondered how much better it could be for about 2 weeks when the shipment of parts arrived and I saw that the bare fuselages were cheap. A quick play with Motocalc produced several options for me including a ducted fan and a dual motor option. Funds for play are scarce with all the new planes out, so I chose to go with what parts I had available in older less flown planes. I purchased the bare foam fuselage, fins, ailerons, motor mount and covers.
The weekend came and I began working on the fuselage. I sanded the whole fuselage to clean up the joint lines and dimples. I wanted this to look the part having a sleek finish just like a real jet. To add more strength to the ailerons, I epoxied a balsa spar where the hinges were to be mounted. I don't want a hinge to give way at the high speed it is expected to do so this should help it a lot.
As a second experiment, I chose to cover the whole plane in fabric and Water Based Polyurethane floor polish (WBPU). I have seen good results in the newsgroups and wanted to try it myself. I also want it to be one plane I keep in the boot, ready for any flying so this will make it ding proof. I first covered the bottom with one whole piece of black organza dress fabric, allowing the WBPU to dry for 2 hours before covering the top with another whole piece (the fabric can be worked into and over curves with a bit of patience). 5 Coats later I had a hard ding proof covering on the plane.
I then proceeded to add all the other standard parts. First, the two fins were epoxied into place and then proper plastic hinges were epoxied into place to fit the ailerons. The Organza fabric does not allow normal sticky tape to hold so I later epoxied a top coat where I taped the hinge gap with clear tape. Some old Hitech HS55's servos were removed from a FFF plane that had seen better days and installed into the fuse perfectly. Some JR 331 servos will also fit perfectly. 2 small 20cm extensions are needed to connect these servos to the Receiver placed in the middle fuselage bay. Any 3 channel receiver will do, I had a JR 700 spare so that got held in place with Velcro. As an extra, I had an old GWS PG03 gyro that I installed next to the receiver to help hold the plane rock steady in higher than normal winds. Next came time to install the original motor mount. I am installing an older Mega 16/15/4 so I had to enlarge the plastic clamps by gently heating each ring. The mega is also shorter than the 480 motor so I may need to extend the rear ring some how to hold the motor - time will tell (initial tests showed this not to be a problem). With all this in, I needed to find where to fit the battery so that I would be close to the required Center of Gravity (CG) (Note - this is 1cm back from the front finger hold cutout under the plane). I am using a 3S 2000 mAh Lipo and as luck would be, is right in the front bay. Minor cutting of the foam that separates the front and middle bay was required. Velcro straps were added that looped under the bottom of the fuse to hold the battery firmly under extreme G forces. The Hatch set was then secured with simple No 2 Wood screws and the CG was spot on.
Static motor tests showed a greater thrust than weight at 20 Amps - Spot on to Motocalc! Now all that is needed is a recharge and wait for the next weekend. Well I couldn't wait for the weekend so I went out after work one night before it got too dark. BOY was I surprised! Initial take off with 1/4 throttle after a gentle toss was good with no drop occurring. As it uses a pusher prop of 7 inches, please be careful as it can catch your hand if you do not toss it right. Only quarter throttle was used until my hand had cleared the plane where half throttle was used to begin climb out with level flight requiring only 5 clicks of down elevator at half throttle. The model reacted quite twitchy so I selected low rates and it was much more sedate. Stall tests were a non-event as it just dropped straight down with no major wing drop (note - the gyro will help maintain a flat stall). I then proceeded to see how full throttle would be. My jet was born! At full throttle, I was able to go vertical until nearly out of sight and then looped over into a power dive followed by a fast and low pass right in front of me. No sound of flutter after this so I may need to try a 7 x 6 prop to see if it will go even faster. I pulled up at the end into another a long and slow vertical roll, backing off to do a stall turn with another fast fly by. I managed to get 3 flights in all, testing the temperature of the motor and battery every 3 minutes before I recharged. Motocalc says that I should get 7 minutes of full throttle joy or 15 minutes good flying if I use a 6 x 4 prop. I have opted to use the 6 x 4 prop as it is enough for general park flying, leaving the 7 x 4 prop for flying at the model club to keep up with the glow boys.
Another weekend and beautiful flying weather had lots of flyers at the club and up to 8 models in the air while I was flying and the 6 x 4 prop was more than adequate to make it fly like the glow flyers. For some it was faster and a lot were impressed with its speed and time in the air. This has now become one plane that I feel has outgrown the local oval and will now only be flown at the field for safety.
Good flying.
Brenton Wildman
Dan's brushless Stryker with an innovative canard wing.
Nose cone from the Pheonix 400
I
want a quote on how much freight it will cost to send items to me.
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