Finishing it up The C-170 can be covered with either light silkspan or tissue and dope, or any of the lightweight iron-on films. Don’t use Mono - Kote or UltraCote as the extreme shrinkage will make short work of the rather light duty structure. Add the desired trim using your favorite method, or custom trim can be or- dered from Callie Graphics at
www.callie-
graphics.com. Begin by gluing all of the hinges in place
with Pacer Canopy 560 or equivalent. Us- ing the wings for reference, align and glue the vertical and horizontal stabilizers in place. Run the elevator pushrod and rud- der pull/pull cables into the fuselage. Tie off the rudder cables and secure them to the servo arm with a drop of thin CyA. The .025-inch steel wire elevator pushrod uses a Z-bend at the front to start. Run the pushrod in and secure to the servo arm in the neutral position. Make a Z-bend at the elevator hinge line and slip the control horn over the bend. Align the elevator into the neutral position and glue the control horn in place. Moving back up front, glue the cabin side windows in place, followed by the wind- shield. Mount the main wheels using the wheel bushing detail drawing and mount on the main landing gear. Fit the tail wheel onto the strut and secure. Make up the flap gap fairings from sheet styrene and glue in place. Bend the flap and aileron pushrods from .032-inch steel wire, align and glue the control horns in place. And finally, paint and detail the cowl and screw it in place. Set up the c.g. 25⁄16 inches from the wing leading edge at the root. Use the battery lo- cation to your best advantage to get a good balance. Make up the battery tray from ei- ther light ply or hard balsa and glue in place in a handy location. Secure the battery to the tray with hook and loop fastener. Set up the control throws as shown. I also set up a 70% dual rate on the elevator and ailerons, but the model is a very docile flyer, so you might not need it. You will also want to add a bit of down elevator trim with flap deflec-
tion. And at this point, the model is ready to fly.
Flying the C-170 Before you fly the model, double check
that all of the controls not only work, but are moving in the right direction—right after take-off is a real bad time to find out that one or more of the controls are reversed! The model handles breezes well, but for trim- ming a new model, a calm day is always the best bet. Ground handling is excellent, so there shouldn’t be any surprises on the take-off roll. Advance the throttle up until the tail comes up, and then add just a bit more pow- er and the model will fly off smoothly. Keep a shallow climb up to altitude and trim for straight and level flight at around two- thirds power. Then to land, reduce the pow- er and let the model descend into the pat- tern. Carry a little power on the approach, and just before touch down reduce the pow- er a bit and flare in for a 3-point touch down. Now, you can start experimenting with
the flaps. Go up to altitude, slow the model down some and drop the first notch of flaps. If the nose pitches up, you’ll need a bit more down trim mixed. Then slow down a bit more and go to the full flap setting. The flaps create a good bit of drag, so to maintain speed, add a little power if necessary. It would be a good idea to stall the model a cou- ple times at each flap setting at altitude so you’ll know what to expect when landing. Each setting is a bit different, so take the time to feel things out before you attempt a landing. Once you have a feel for the flaps, set up
the approach with one notch of flaps, then work your way up to the full deflection set- ting. Keep the nose down a bit to prevent the model from getting too slow on the ap- proach. In the end, you’ll find that the mod- el lands well at any flap setting, but with full flaps will slow down very nicely, but never leaves the feeling that it’s going to fall out from under you. Meanwhile, for a little ex- tra fun, shoot a few wheel landings with full flaps, and as soon as the mains touch, im-
mediately go to the take-off flap setting and power up for another go around. And that’s all there is to it. The C-170 is a straightforward “stick and tissue” style build, and a very docile flyer. And as an added bonus, the C-170 will make an excel- lent first flap airplane.
In flight the C-170 is a smooth docile flyer. Because of the flaps, the model has a wide speed range, and can be flown in and out of some very tight places.
FLYING MODELS 25
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