14 Jul 08 About the Project

I am building a Vans RV-7A, which is a two-seat side-by-side all aluminum tricycle-gear aircraft.  I will complete this with a tip-up canopy.   Thats about all I know for sure.  There is a lot of decisions to make during this process.

• Prime – I have chosen to use a somewhat minimal approach to priming.  After reading at great length about the myriad of choices a builder has in priming, not to mention the opinions out there, I came to the conclusion that most home built planes are over-primed.  I’m sure over-primed is better than under primed, certainly due diligence must be paid to the scuffed, scratched, and raw aluminum pieces.   My primary concerns were:

• • Environmental.  This is of big concern to me.  For not just the local environment (toxic chemicals down the storm drain, in the air, etc) but also for the immediate environment (me).  I decided early on whatever choice I went with it must be environmentally friendly.  This narrowed down the options.
  • Cost.  Not a huge consideration, it seemed that even with materials, tools, etc. this wouldn’t be a big factor.
  • Time.  How much time was I going to add to the project with my primer choice?  A lot of the prep work and priming appears to take a considerable amount of time.  Plus I’d already spent all my time researching!
  • Builder opinion.  In talking to other builders, and reading forums online (VAF!), I started to see a common theme.  Many 2nd time builders, and lists of “what I’d do differently if I was building again”, chose to only prime the surfaces where metal meets metal, and chose to use something less complicated.
  • Decision.  I chose to use NAPA 7220 Self-Etching primer.  I’m going to prime all parts that:
    • Are scuffed, scratched, flutted, etc.
    • Surfaces where metal will join other metal.  I will attempt to only prime ribs, spars, and not skins.
    • Any raw material (eg: non-alcrad aluminum)

Choices going forward:

• Engine
  • At this point (early on) I’m leaning towards a new horizontal-induction XIO-360-? rated at 180 HP (Aerosport? TMX? XP-360?).  I feel this is a good balance of price, performance, weight, and complexity.  I’d like to go with roller tappets, no mags (Light Speed plasma II?) or Slick Mag + Light Speed?.
• Propeller
  • Constant Speed, maybe.  ~Triples the initial cost, plus maintenance.  Adds to the cost of the engine.  Adds complexity.  But might make up for this in performance and efficiency gains.
• Avionics
  • IFR. EFIS + backup. I like the way the Advanced Flight Systems EFIS looks, but I’m a ways out from purchasing, and the options are being updated rapidly.
• Paint.
  • Maybe.

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