Altech Marketing: F-22

Model Airplane News, Jan 1998 by Olivett, Vic

A sport model that thinks it's an advanced fighter

AFTER BUILDING THE Altech* F-14 Tamecat designed by Jeff Troy. I looked forward to doing Altech and Jeff's latest project, the F-22. The kit comes in ARF and ARC versions and. because I'd rather spend time at the field instead of in my shop, I chose to build the ARF model. which comes covered with Coverite and painted. The F-22's construction is unique; both the fuse and wing are solid foam and sheeted with balsa. The kit includes a good instruction manual and a hardware package that contains all the necessary pushrods, clevises, wing bolts and screws.

A very important point before getting started: do not use any CA adhesives in areas that contact foam. As with all ARFs, check all of the factory's glue joints. I found that the rear bulkhead, where the threaded wing-bolt blocks were mounted, needed some reinforcing.

TAIL FEATHERS

Remove the covering over the slots at the rear of the fuselage (there are two for the vertical fins and two for the horizontal stab). I also removed the covering on the fuselage, both in front and to the rear of each fin, to provide more gluing surface. I used Z-Poxy* to glue the tail feathers to the fuselage. To ensure proper alignment, hold the assembly in place with masking tape until the Z-Poxy cures. I temporarily hinged the elevator in place to hold the horizontal stab for gluing. I had to use a Dremel tool to remove a small portion of the foam at the rear of the fuselage for elevator control horn clearance.

FUSELAGE

The radio compartment is covered with an 1/8-inch plywood plate and is held in place with four screws. The rear of the plate has two openings for the rudder pushrods. These may have to be enlarged, depending on the type of servos you use.

The landing-gear block is already installed and drilled. Just remove the covering and add some Zap-A-Dap-A-Goo* to prevent fuel from seeping under the covering and screw the two metal straps in place.

The engine mount you use will determine the location of the nose-gear bearings. I used an Enya* .50 CX for this project and had to make the steering arm exit under the fuselage. The front of the fuselage is glued with Z-Poxy to the main portion of the fuselage. I used 1/4 x 1/4-inch pieces of scrap balsa to hold the front portion of the fuselage tight against the sides of the rear portion while the glue cured. Medium Zap worked well for the cowl mounting blocks.

WING

The wing panels are sheeted foam and are very well made. They are joined using two 3/8 x6-inch dowels. After I was satisfied with the fit of the wing joint, I applied a liberal amount of 30-minute Z-Poxy to the wing roots and inside the joiner holes for the dowels. After the panels are joined, wipe away any excess epoxy with rubbing alcohol and a paper towel. The wing is allowed to cure upside-down with a block at the rear of the trailing edge (TE).

The two aileron torque assemblies are placed into the slotted TE pieces and then glued to the TE of the wing. Add some clearance so the torque rods can move smoothly. When you're satisfied with the fit and movement of the torque-rod assemblies, glass the center section of the wing with 30-minute Z-Poxy. All the control surfaces have been slotted for the CA hinges. Pre-fit the ailerons and check for proper movement. The precut servo hole may have to be enlarged, depending on which servo you use.

When I aligned the wing to the fuselage, I found that the blocks for the wing bolts needed some added support. I used a piece of t/s-inch ply to secure the block to the foam in the fuse and added some 30-minute Z-Poxy. After the wing is bolted into place and alignment is correct, hold the front of the wing tight against the fuselage and drill the 1/4-inch holes through the front bulkhead and into the front of the wing.

The ABS cockpit deck is fastened to the fuselage using brass eyehooks and rubber bands. This system works very well; however, depending on the type of tank you use, some adjustment to the eyehook in the cockpit deck may be needed.

ENGINE AND RADIO

I chose to use the new Enya .50 CX to power the F-22. This engine is in the new high-performance CX line. The engine fits well into the cowl with a little Dremel tool work.

I also used a JR XP642 with NES 517 servos. The new generation of radios is great; this one features servo reversing, end-point adjustment and expo, which make radio installation easy. The F-22 comes with all the pushrods and clevises needed for the installation. All the control surfaces were set as per the instructions for the initial flights.

CONCLUSION

The nice thing about a modeler designing a model is that he knows what we need and what we want: performance, reliability, ease of construction and low maintenance. Jeff Troy and Altech Marketing have done all of the above with this winner. This model will get your heart pumping and make you look like a pro. Whether you're a novice or an expert, you will really enjoy building and flying the Altech F-22.

*Addresses are listed alphabetically in the Index of Manufacturers on page 158.