REFLECTOR: barn door speed brake

[David Staten]

The following formula WORKS.. well... from spam cans to big iron.. a 
MD-11 pilot/ GA CFI told me about it.. I've used it in Tigers. Mooneys, 
Bonanza's, Arrows and Cardinal RG's..

take your height (in thousands) and multipy by 3
going from 22 000ft down to 2000ft = 20 000ft loss
20 x 3 = 60
start descent 60 miles back

What should the descent rate be?
take your ground speed and add a zero, then divide by two.
g/s 260 KT: 2600/2 = 1300fpm

I end up having to add a few miles or I end up a tad high, because in 
spam cans I dont pull much power, just push the nose over and trim, so I 
have to recalculate as I go. As a general rule, in a NA plane, I keep 
the inches of MP constant (on applicable planes) as I descend.. pulling 
the throttle slowly back as the miles click by and the altimeter 
unwinds.. End up approaching the airport in low altitude cruise at about 
20 inches MP..

This profile also works good for going into busy commercial places, 
because you keep your speed up in the descent.

(I also have no velocity time.. but physics are physics..)

Dave


Richard J. Gentil wrote:

> I would think that unpressurized, you climb as fast as you want but 
> you come down on average, at 500fpm. Much more then that and you start 
> hurting the Pax ears. Most of the time I will start screaming for 
> lower a couple minutes before I end up at the 2 minutes from 
> destination for every 1,000ft I am AGL.
>
> Since I have yet to fly a Velo, anyone know in an SE RG what speed 
> indicated you hit when you keep cruise power (65%) and a 500fpm 
> descent rate?
>
> Richard