Re: Power Loading

Douglas R. Jones (
Mon, 15 Jan 1996 10:16:41 -0600

>I went through a pile of Windsock datafiles and pulled out the
>following figures for some fullsize WW1 aircraft. I also tried to
>find the article about power loading in "Radio Control Scale Aircraft"
>without success. I just ran my finger down the TOCs trying to identify
>the article, no luck I am afraid. However the following might make
>an interesting comparison with experiences and perceptions of "scale"
>flight for R/C models.

This is an interesting comparison. I hadn't given much thought to this topic
until now. I had done what most folks.....and put the recommended motor on
the kit and go fly! I tend not to put the biggest recommended motor as i am
interested in scale flight not unlimited verticle!

I would love to hear Larry M's or Guy Fawcetts comments on this stuff. I
think Larry has once told me that 50 - 60 watts/lb of aircraft is a
reasonable working number for these kinds of planes. Surely there is a
conversion between watts and hp somewhere. So we could get an idea for
electric power.

Doc Crabb has put forth the idea that if one uses fabric and paint on these
types of models that one needs more power. SImply because of the increased
drag that the "rough" surface has. This might be true but I suspect that
your 8 lbs/hp figure is reasonable.

>Of course power loading isn't everything. If a prop has zero
>efficiency ( eg a feathered prop) it will absorb 100% power and produce
>no thrust. Similarly nominaly the same spec props for models will produce
>different amounts of thrust with the same engine (or electric motor).


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