Need Information To Do A 150 Hp Conversion On My C-150

In rec.aviation.owning Homesick Angel wrote:
: The bigger engine will drink more fuel, so it will cut down on the
: amount of hours you can fly. Can't remember the exact numbers but
: probably run out in about two hours.

I don't normally buy this argument. With very few exceptions (planes that are
horribly underpowered to begin with), more HP doesn't buy you appreciably more speed.
Power required goes with the cube of the speed, so normally powered planes aren't much
slower than souped-up ones. Just because you have more power, doesn't mean you need
to use it. (and in most cases it's silly to do so). If you pull the power back on a
bigger engine, it'll burn roughly the same amount of fuel as on a smaller engine.

There are only a few things to counter this...
- reduced efficiency running at really low power settings on a fixed pitch prop (CS
running oversquared would help a lot)
- Added weight of the larger engine (generally not too much anyway)

: I usually fly conservatively, so I'd fly at say 50% power instead of
: 75%. It was so much fun taking off and landing that about all I did

... So they should burn almost the same fuel... It's the same 75HP whether its
75% of 100 or 50% of 150... roughly 5.5gph.

Of course climb/hauling is the real (and legitimate) reason to do it.

-Cory


************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************