REFLECTOR: To Turbo or Not

[Scott Derrick]

I think part of my indecision is the question, "Does turbo charging make
my airplane more efficient?". 

Last years fuel prices  were an indication of  what we will see  in the
near future.  Once the world economy gets back to burning fossil fuels
at a greater and greater rate, prices will rise again. 

The Velocity is a very efficient airframe once airborne, though it has
its  problems.  For me that was  using way too much runway at  the
airports a frequented. 

Taking Chuck's question about mission to the problem.  Do I really need
325 HP vs 285 HP at takeoff, to solve the problem that initiated  this 
engine upgrade.   Getting off the ground at high elevation airports in a
reasonable amount of runway, in the summer at gross weight.

Am I sacrificing efficiency  for a Tool Time Velocity?   The  IO360  was
definitely  deficient at take off at elevations above 4,000.  Above 6500
it could get downright scary.   But is a TSIO520 going overboard when a
IO520 would do the job.

I was fairly happy with the cruise speed of 170 ktas that the io360
produced.  Especially at 9 gph.  With higher fuel prices a future drop
dead certainty that is a huge plus.  I've been told an optimal turbo
system uses 10% of the HP just to support itself.   Thats 33 HP for this
520.  Meaning the engine is actually producing 350HP to get 325 to the
prop.  I wonder how much in gph that costs. Seems like its going to
raise my cost to 10.5 gph, to go 170 ktas. 


Scott

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