Great Planes Fokker DR.I ARF

Model Airplane News, May 2003 by Ziroli, Nick Sr

MODEL AIRPLANE NEWS

FLIGHT TEST

I have been building model airplanes for more years than I care to think about, and I've learned to recognize good engineering and high-quality construction. A critical inspection of the Great Planes almost-ready-to-fly (ARF) Fokker Dr.1 indicated that it excels in both these areas. This is an all-built-up model that is beautifully covered with Top Rite MonoKote film. I came across a few minor items that I thought could have been improved, but when a model is this good, it's difficult to find serious faults.

LET'S GET STARTED

This is a very complete kit. You'll need a radio system with five servos, a Y-harness and servo extensions and a prop and fuel line. A .46 to .60 2-stroke engine or a .52 to .70 4-stroke engine is recommended; I went with an O.S. FS-70 Surpass and found it to be a very good match for the Dr. 1. The only other item that is optionalbut should be installed-is a 'A-scale pilot bust. The excellent 35-page assembly manual is well illustrated with many detailed photos, and it includes a list of required accessories and tools. I used Zap CA and epoxies throughout.

* Landing gear. Assembly begins by mounting the prebuilt and painted landinggear assembly on the fuselage. All holes are accurately predrilled for the sheetmetal mounting screws; you just need to file or grind flats at the ends of the axles for the wheel-collar setscrews. The tailskid is made out of prefinished plywood and has been epoxied into a socket at the rear of the fuselage. I thought it could easily be broken off, but dozens of flights have proven me wrong.

* Wing assembly. Completing the bottom and middie wings involves gluing the wing-- mounting dowels in predrilled holes and mounting the strut brackets using sheet-metal screws.

As with the landing gear, all holes are predrilled. The strut-mounting brackets are heavy steel, each with one hole tapped for the strut-retainer screw. Some brackets are bent to 90 degrees and some to 60 degrees, so be careful to position them properly.

The top-wing assembly involves mounting servos and ailerons. You are instructed to permanently hinge the ailerons first. Instead, I chose to fit the CA-type hinges and glue them only to the ailerons. Make sure that the ailerons fit property. Note how the white field and black cross line up perfectly. Cut open the servo openings, and mount the precovered covers using sheetmetal screws. Remove the covers, and mount the servos on the wooden blocks that have been epoxied to the inside of the plate. You'll need a Y-harness and one 12inch and two 6-inch extensions to connect the servos to the receiver. The manufacturer was thoughtful and built a string into the wing that can be used to pull the leads through. Remount the servos, and put the ailerons into place. Position the horns and mark their locations, then remove the ailerons and mount the horns. This is much easier to do before the ailerons have been installed. Glue the aileron hinges into the wing, and install the pushrods. Mount the strut brackets to complete the top wing.

Mount the bottom and middle wings on the fuselage. I decided to add a balsa filler block between the mounting plate and the wing surface at the wing-mounting screws; this takes the bending strain off the mounting plates. Mount the lower interplane struts. These are made out of hardwood, are well finished and are numbered so there is no question where they should go. Socket-- head capscrews hold the struts in place. Fit the center-wing cover to the center wing, and glue it into place. I found it best to leave a small flange at the wing surface, since this part is a little short to evenly fit with the fuselage. With the guns in place, it isn't very noticeable. Now, mount the last two 90degree brackets on the nose of the fuselage. Attach the prepainted sheet-metal cabane struts (very nice!) to the fuselage, then add the top-wing and interplane struts. All of my wings lined up perfectly.

* Tail feathers. Cut

away the MonoKote on the stabilizer and fuselage so there will be a wood-to-wood glue joint when it is mounted. Test-fit the hinges, but don't glue them yet. Set the stabilizer in place, and check to make sure that it's parallel with the center wing when it's viewed from the rear. I needed to add a very thin shim under one edge. Align the stabilizer to the center of the fuselage, and glue it into place. Hinge the rudder. At this point, I glued the hinges to the elevators and rudder only. As with the ailerons, I prefer to attach the control horns before I hinge them.

ENGINE INSTALLATION

Remove the wings, and bolt the motor mount to the firewall. A template is provided to accurately position the mount to suit a variety of engines. I highly recommend the O.S. FS-70 Surpass. Position the engine on the mount, mark the hole locations, drill and tap the holes and screw the engine into place. Align the throttle arm with the firewall, and drill a hole for the pushrod. Make sure that it will clear the fuel tank inside.

The pushrods are 0.074 inch in diameter and go through slightly curved guide tubes. I fit each pushrod to the tubes by slightly arching them. A little trial and error will make them fit freely for the inch or so that they will travel. I used five standard Airtronics 94102 servos with 50 oz.-in. of torque, and this proved to be adequate. There is enough room in the servo mount for an additional servo on each elevator, if you like. With the control surfaces in place, mark the correct position of the control horns. Remove the control surfaces, mount the horns and then permanently glue them into place. Install all the radio systerns, and set up the control throws, as indicated.