Generally speaking it's not power that gets you airborne but lift. Generally
the wing produces lift. Higher thrust may get you to flying speed more
quickly but if the A/C weight is higher then acceleration takes longer and
the lift required and therefore the take off speed higher.
If the aircraft configuration permits a higher wing angle of attack during
the take off role then the increased power may allow the aircraft to take to
the air more quickly with an increased pitch angle, however this may mean
taking off at or below the power off stall speed which is not generally
advised.
Once airborne the thrust from the propeller does contribute directly to
lift. I think a 100 hp Rotax produces around 200 kg of static thrust which
converts back to about 50 kgs of lift at 15 degrees pitch angle. At 60 kts
the thrust will be less than 200 kg. Of course a more powerful engine of the
same weight will get an A/C airborne more quickly. With a heavier engine the
situation is more complex.
Maybe quicker to T/O then again maybe not.
Jerry
Jerry@ban-bi.com or LTS@avnet.co.uk
www.Ban-bi.com or www.avnet.co.uk/touchdown
----- Original Message -----
From: "Alexander P. de C. Kaarsberg" <kaarsber@terra.com.br>
Subject: Re: Runway length
> ......but the diesel is said to compare with 150 hp engines in
> performance due to the higher bottom-end torque, so i'd expect need for
> less runway?
>
> Alex, #529
>
> KarkelB@aol.com wrote:
>
> >mmmm....... wilksch WAM120 with MT prop.The two are the heaviest in their
> >respective categories. I reckon you will need a good length of the runway
to
> >get airbourne!!!
> >
> > karim.
> ># 420
> >
> >
>
>
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