Tech. Counselor: Mr. Lee Lawson: EAA - 134030

Visit: First

Inspected: Tail Components

• Round all exposed sheet metal corners
• Make sure to use the correct riveter nose piece: The Riveter available at ZAC only had the A4 rivet head and we were not told to change it. As such, some of the A5 rivets on the rudder are "pinched" along the perimeter. Consider drilling out and replacing.
• Review all ass'y and installation notes along with previous builder experiences in order to I.D. any parts that are better left un-riveted until final ass'y.

• Include a regular inspection of the A5 rivets holding the rear bracket to the rear spar. Some of these rivets show a longer back-side stem than others. Although heads appear to be seated well and parts are firmly clamped together, these longer stems may loosen with use. Is this is observed, consider replacing and maybe use Cherry Max rivets of similar grip length.
• A good deburring technique is to use the rat-tail end of files along trimmed sheet metal edges, such as the upper surface control cable cut-out. He demonstrated this technique.
• Make sure the final sheet metal trim is no more than 1/8" to minimize wrinkles in final part. Off-set shears are superior to straight snips.
• For overlapping skins, use a flanging tool to impart a very slight inward set to the sheet metal edge. This will produce a very tight seam along the OML. This technique has the greatest impact on large wing or fuselage joints.
• Smooth out relief cuts on rear support bracket using a larger radius file or deburring tool. Knock-off any sharp edges.
• Regarding the outboard stab-to-elevator hinge brackets: Look into some thin-walled brass bushings to avoid direct pin to aluminum wear problems. However, need to insure proper edge distance is maintained if hinge plat hole is drilled out for a bushing.

• Skins are fairly tight, but outboard bays have some slight oil-canning. This is typical for such designs with relatively wide rib spacing. Some metal builders use a technique of assembling skins under heat lamps to get some shrinkage at room temperature.

• Photos of the completely primed structure are good to show extent of technique:
• All metal to metal flanges
• All rivet heads
• A light dusting on all internal skins and structure
• A fully primed A/C will be a selling point in the future.
• Make sure to take photos with the primary builder doing work on the A/C parts. The final inspection paperwork must provide evidence of who built the A/C.

Engines -

• You can't go wrong with a Lycoming for parts and service, but whatever engine you select, make sure that someone else has gone through it in an 801 first to avoid the learning curve.
• Franklin's 6-cylinder should also be good and is probably much smoother running than the 0-360. Some reports suggest that the Franklin has a faster spool-up time, although this is unconfirmed and not intuitive.
• Stay away from the LOM: Heavy parts that may not be readily available, it may also lack "un-sleaved" cylinders, which reduces the re-work capacity of the engine.
• HOWEVER - get as many unbiased reports about engines as possible before deciding. Unbias is difficult to get since most owners will defend their choice, even if it's a dog.

Propellers -

• Wooden props can be much lighter than metal.
• Go for the largest diam. Prop possible.
• For the 801 speed range, fixed pitch props probably make more sense. Constant speed props will probably add more weight for realized performance gain. Weight added for drag reduction (fairings: Wing struts, Nose wheel strut, main gear, etc.) will probably yield higher performance payoffs than weight used for thrust production (variable pitch props).
• There has been some bad press on in-flight adjustable props due to fatigue failures. Check-it out thoroughly if looking in this direction.

Fuel System -

• An engine with fuel injection is a nice addition and improves cold weather starting.
• Fuel injection requires the installation of a fuel return line to one of the tanks.
• Metal fuel lines require special precautions during installation to provide for strain relieve/isolation and fatigue protection. Also, connections require swaged fittings to minimize leaks.
• Don't overdue the adhesive on the cork vibration dampers - every once of weight is performance lost. Also, replacement is easier if the cork is just "tacked" on at spots.