Summary of Contents for AviPro Aicraft, Ltd. Bearhawk N33RB
- Page 2 Wings: Getting Started When the wings come to you, after you’ve drilled out the pop rivets installed for shipping, this is what you have: nearly complet - ed wings needing only the systems installed and the top sheet riveted down between the spars. You’ll have to come up with a system of curling the sheets back so you can work on the inside of the wings.
- Page 3 lose control for a second and dent something. The tops aren’t even remotely heavy (25-30 pounds), but have an extra set of hands ready to help. The flaps and ailerons are packed on top of the top wing and covered with foam. Because the foam is so light, don’t attempt to unpack the wings in a wind because it’ll pick up the big pieces of foam even as you try to get them out of the crate.
- Page 4 On Building A Wing Rotisserie Bolts Nuts Nuts Although a rotisserie is a long way from Used Torque Used Torque AN365/ Inch-lb. AN364/ Inch-lb. being necessary, we thought we’d share what one AN310 AN320 builder fabricated to make his life easier, and it 10-32 20-25 12-15...
- Page 5 Wings: Installing Flap Skin Stiffener 4. Top skin and flange have both lines of holes drilled and dimpled and the stiffener has matching holes and dimples Drilling the Stiffener (if it isn’t drilled) In most of these cases, the stiffener has no holes in it, but both the spar and the skin are drilled and dimpled but an additional line of holes and dimples needs to be made between the...
- Page 6 push the aluminum around. However, there is a way to prevent that. Buy a heavy, extruded aluminum angle (1/4” thick, 2” or so wide) and squeeze the rivets using the angle as both a straight edge and as an interface between the squeezer the heads of the riv- ets.
- Page 7 Wings: Installing the Flap Actuation System Install Torque Tube The torque tube slides through the steel stand-off bushng at the root and through a similar bearing stand-off at the mid-wing cross member. Before sliding the outboard end into the bearing note that one of the outboard arms has to be slid in place first (see photo).
- Page 8 flap push rod between them to hold them in align- over) and center punch where you’ll drill the hole ment. Then clamp the top end of the push rod in the arms. Then drill one arm with a fresh 1/8” bit where it bolts to the arms down to the crossmember (make it fresh, so it cuts cleanly and easily).
- Page 9 Wings: Installing the Aileron Actuation System all 1/8” stainless) attach to the end of the control stick push rods, run up inside the lift strut into the wing, around a pulley at the top of the strut that routes the cable back to the aileron bellcrank, then back toward the fuselage where it continues all the way across the inside top of the fuselage and into the other wing where it makes a similar “U”...
- Page 10 Cable Guards Where the cable comes off the front pulley It’s not unheard of for a control or flap cable and goes down inside the lift strut, it’s possible you in an airplane, any airplane, to run off the pulley. might have to file a little off of the edge of the strut For that reason, every pulley in the control/flap sys- to get clearance.
- Page 11 Wings: Installing Tip and Root Ribs The shortening of the bottom stiffener has been mention, but we’ll discuss it again in relation to the root rib. Briefly, in a few airplanes, the bot- tom flap bay stiffener is 3/4” too long and must be shortened to allow attaching the root ribs.
- Page 12 NEW (2016) Additional Guidance for drilling wings to fuselage. READ THIS FIRST, before the following section! Over the years we have seen some customers occasionally have problems drilling their wings to their fuselage. So Bob Barrows and Bearhawk Aircraft have written i nstructions detailing Bob Barrows’ best guidance on how to undertake this important task. If you follow t hese instructions at t his link , you will have good results. leveled fore and aft AND left/right. Fore and aft leveling can be ...
- Page 13 lage and keep messing with shims under the land- to determine if any difference exists. ing gear until the other hole lines up with the sur- 4. If FRONT wing holes are within toler- face at that end of the tube. Rather than using the ance, drill them on the bench.
- Page 14 ing at the same angle. We’ll address that later, but at all, it will probably be the top of the front hole in for the purpose of measuring the fitting angles, just the front fitting and the bottom of the back hole in having the rods bridging the distance between the the rear fitting.
- Page 15 highly unlikely because the fittings are generally Do the same thing for the rear spar BUT well within tolerances. MEASURE THE HOLE ON THE FRONT FACE If, after drilling the holes to size, some OF THE SPAR. angular difference still exists, it can be corrected Now, repeat exactly the same process on the when drilling the wing spar holes to size in the next other wing and compare the two.
- Page 16 Although bench-drilling the holes in the wing spars can be done free hand, a simple drill block, as described makes it easier. Also, under-drilling and reaming gives a better hole. back, both go the same direction e.g. up or down, Even when using sheetrock lifts to handle the wings, it is still then the rear difference is subtracted from the front very much a two-man job.
- Page 17 possibility of dropping that end of the wing, if pair of Vice Grips, it won’t be bent. There’s a high something should let go. Put a washer/spacer inside probability the front fitting will be tight enough that the rear fitting before the rod goes into place. it will determine where the rear wing spar goes and 3.
- Page 18 In most cases, the level won’t be exactly the right length, so make up a very straight board with short pieces of 1 x 2 glued to the bottom at each end. These stand-offs will be positioned in the mid- dle of each spar and the measurement taken off the board between.
- Page 19 Wings: Setting the Dihedral and Making the Struts 11. Remove and drill another hole for the top fitting. 12. Reinstall for one last check 13. Remove, drill rest of holes in one side of strut only. 14. Insert fittings inside strut and use fitting to guide drill through other side of strut.
- Page 20 read a ruler or dial caliper in mid-air, cut a piece of aluminum sheet to 3” and use it as a gauge on both wings. It’ll be easier to read with less interpretation on your part. Make sure you’re measuring from the same part of the skin, meaning, the lower, outer surface right on the edge.
- Page 21 Here’s another approach to making sure the initial holes are Step One: bolt the fittings to the fuselage and wings and clamp the struts to the bottom of them. We’ll position and drill the bot - drilled square to the strut. The center punched hole is done the same way as the pix at left and a wood, screw-together tom fitting first.
- Page 22 The bottom fitting is now secured with two bolts and we can do the top fitting. Drill Top Fitting Holes As a last minute check to make sure nothing moved, put the strut back up on the airplane with the bottom fitting bolted to the outside of the strut and the top fitting still clamped to the outside.
- Page 23 pencil line across the fitting. Clamp it in position twirling a large diameter bit in the holes with your with the clamp over the outside hole, make sure it fingers. You want to just barely break the edges. is square, and drill the second hole in. Put a bolt in Hey, guess what? You’re ready to bolt them that hole and put the strut back up on the airplane.
- Page 24 Wings: Install Flaps and Ailerons paint. On later kits, the hinges are painted and already have pilot holes. Before you can begin hinging the flaps and ailerons, you’ll have to remove the gussets that have been temporarily pop-riveted over the hing- ing areas, both top and bottom.
- Page 25 aileron/flap cutouts so you have the control sur- vertically on the control surface’s spars. The left faces installed in the right position vertically. and right positions of the hinges on the control sur- Bolt the hinge pieces to the bearings (left face “cut outs”...
- Page 26 but will be in due time. They are: - Pouring lead in the aileron balance tubes - Final riveting the trailing edges Balancing the Ailerons This can be done at any time after the ailerons are hinged to the wings. To balance the ailerons we’re going to pop rivet or sheet metal screw a 3/4”...
- Page 27 plug for the end or stick it slightly into the ground local gun store that sells reloading supplies and get to seal it. Make sure the can or ladle you’re using the finest lead shot they have. You want nothing bigger than 8 1/2 (the bigger the number the small- er the shot) and finer is better as there will be less air space in it.
- Page 28 tube. It should be at least 5.0 pounds and a little heavier is better. Turn the tube over and remove a little shot to give enough room to form another epoxy/shot plug in place and you’re finished with this process Now, slide it in place.
Need help?
Do you have a question about the Bearhawk N33RB and is the answer not in the manual?
Questions and answers