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Builder's notes:

• The joining of the side trusses at the forward end is critical. The squareness of it will determine how well everything from the firewall back will fit together. Mike Fisher includes a recommendation right on the blueprint for accomplishing this, but I found it impossible to follow, as it seemed to require an act of magic to levitate one side over the other for the duration of the epoxy setting up. Once again, my father stepped in and designed a simple jig to accomplish this, pictured here as a line drawing.
  

  The jig blocks are made from ½" or ¾" plywood cut into a right triangle, with the tall edge being as perfectly straight as you can make it. The triangles are screwed to a section of 2x4 along the short leg of the triangle, and these are screwed down onto the table (long deck screws work well for this). Place one of the fuselage sides sheathed-side down on the table and position the jig blocks. Two along the upper longeron, and one at the forward end, screwed down when they have been positioned. Sand bags or other heavy weights will keep the fuselage side from moving during the join operation. Not shown here, but essential for this jig to work are 1x2's near the top apex of each jig triangle which are clamped against the plywood and extend up and in toward the interior of the fuselage side, making a "V" at the top of each jig. The second fuselage side is lifted and set on the tops of these additional supports. Loosen each clamp in turn just enough to allow the extension to be rotated and hence draw the fuselage side up against the flat edge of the jig triangles, the same as the fuselage on the table surface. You'll need to move it carefully to not disturb any of this house of cards, and you'll need to cut some lengths of 2x4's to place between the fuselage sides toward the tail end and away from the jig supports to hold the "levitated" side flat and level. With both fuselages sides snugged against the jig edges and secured, you can proceed to cut lengths of ¾" x ¾" wood stock to join the two sides at stations specified in the blueprints, and attach the firewall plywood bulkhead.

  Our result was a square join with an error of no more than 1/16th-inch. Mike Fisher seems to accept larger join tolerances, but I think this only adds to the work at the end when you have to rig the airplane for proper flight. In general, we held to symmetry & join tolerances throughout the structure of 1/8th-inch or less. Remember this: you are building one-off sub-assemblies over many months which must fit together well in the end for the airplane to fly well. All care for tolerances up front will pay off at the back end.

• A note on the cockpit flooring. The blueprint calls for a double-sheathed floor structure running from the firewall bulkhead to just aft of the front cockpit, then the top (interior) plywood is left off so that the rear cockpit has only the exterior plywood for flooring, with some cross pieces exposed between the fuselage sides. There is no reason not to extend the double-sheathing all the way through the rear cockpit, or at least to just under the projected edge of the seat pan, where your feet should never end up anyway. The additional weight is negligible, and it will provide sturdier footing when stepping down into the cockpit. In fact, you should never step onto the single-sheathed flooring but instead step directly onto the main wing spar carry thru. As it is, I have to rely on a couple of "No Step" decals on the rear cockpit floor to remind me not to put my weight there. So far so good, but I worry about guest pilots who, in their eagerness to be seated, may miss the warning and step there anyway. As good as the T-88™ epoxy is, I don't know how well it will stand up to repeated weight being applied in direct tension to the contact surfaces where the plywood joins the bottom surface of the bottom longerons. A little extra plywood here will payoff in peace-of-mind.

• Now for the really big modification recommendation. Install a ballistically-deployed whole-aircraft recovery parachute! Do it! I guarantee if you ever need it in case of catastrophic structural or engine failure, or something avoidable, like running out of fuel over inhospitable terrain, neither the expense nor the effort involved in the modification - both of which are admittedly major - will matter one whit. The airplane will probably be un-salvageable, but your chances to live to fly again will be much improved.

  I talked to the two then-extant manufacturers of such systems - Second Chantz, and Ballistic Recovery Systems. The former has been out of business for awhile now, but BRS, as far as I know, is still open. I decided for the BRS unit, because they were much more concerned for correct placement for optimal deployment, and for structural modifications to insure the integrity of the aircraft structure against the forces applied to it during the parachute's opening phase of deployment. Second Chantz, on the other hand, only seemed to be concerned with the aesthetics of hiding the unit. Some decisions really are no-brainers...

  I worked closely via telephone with Jeff Peltier at BRS, discussing various placement options and engineering concerns. I eventually sent the fuselage blueprints to him, from which he worked up a series of engineering change orders based on his extensive knowledge of their system's requirements, and testing (to destruction) of a similar, earlier, Mike Fisher design - the Fisher Flying Product's Classic™. For liability reasons, I can't pass these on, but you can contact the folks at BRS to see what their current recommendations are.

  BRS Inc.
  300 Airport Rd. South St. Paul, MN 55075 651-457-7491 651-457-8651 (fax)

  I will say this much about the changes. The interior of the fuselage sides, from the firewall to the rear cockpit, must be sheathed with the same 1/8th-inch plywood as used on the outside. Basically, this sheathing is one giant gusset plate. The absolute best time to install this extra sheathing is before joining the two trusses. In fact, while the sides can be handled separately, and flat, this modification is almost trivial. Trust me when I tell you that after joining, it is a major operation! The extra plywood adds weight, of course, but it is roughly centered, fore & aft, around the center of gravity, so it doesn't have a big impact on the balance. The placement of the parachute unit itself adds both weight - about 30 pounds - and, where we located it, aft of the rear cockpit and under the turtledeck (more about that later when the picture comes up) - affects the balance. With the original, non-electric, C65 engine, we had to add 15-20 pounds of weight to the firewall to balance the parachute's being so far aft of the datum. When we changed the engine out for a C85 plus electric start with battery, and fuel pumps, the dead weight on the firewall was no longer necessary. A much more productive use of weight up front, in my estimation.

  A note of caution here. We were just plain lucky that the balance worked out after the decision to install the parachute unit, because we had chosen the smaller engine and its correct spar carry thru truss block positions before the subject of ballistic parachutes came up. Without a doubt, the decisions of engine size and whether to install a parachute system should be made before you begin to fabricate the fuselage side trusses.

• I cannot over-stress my recommendation to buy a ballistic parachute for the airplane. It could well save your life - there are dozens of documented saves to date - and the life of any passenger you may be carrying (and who of us doesn't want to share this kind of flying with friends?). Especially consider the passenger's situation. While you are in the rear cockpit as pilot-in-command, and out from under the top wing, and might be able to get clear of the aircraft if you are wearing a personal parachute, the passenger is completely between the wings, inside the cabane structure, and in a smaller space (I doubt that anyone over 160 pounds could get in wearing either a backpack or seatpack parachute - the front cockpit is that small). I put the chances of a passenger being able to exit the aircraft and surviving at slim-to-none. Also consider the altitude factor. This airplane is not intended to be a high-flyer, but a low-altitude recreational sportplane. Do you think you and a passenger can get out of an airplane falling through 2000-feet AGL and still have time to deploy personal parachutes? I'm not willing to risk it, especially on behalf of my passengers. I can't imagine drifting down under canopy, alone, watching my airplane and passenger auger in. Or rather, I can imagine it, and that's why I installed the BRS unit. Think about it. Sermon over & soapbox put away (for now)!