Stealth Pilot[_2_]
June 9th 08, 02:15 PM
gatts post on the dive spped of a trimmed power off aircraft seems to
have vanished off my free agent.
I experimented in the Tailwind on sunday to see what occurs on power
off.
now mind you the Tailwind isnt the usual FAR23 aircraft. It has no
dihedral, neutral stability and not much inertia. it is however a dead
honest airframe.
I tried the suggestion regarding spiral instability while tootling
over to Cape Naturaliste.
If I set up the tailwind in balanced straight and level flight and
take the hands and feet off everything the aircraft dives off in a
spiral, which you'd expect from a neutrally stable aircraft
encountering a gust.
I tried setting everything up in balance then held my feet still on
the rudders, hands off everything else. the aircraft flew with slight
deviations in almost straight and level flight for 10 minutes or so.
It showed no tendency toward instability which I must say surprised
me.
I then ran out of country and turned around back toward Busselton.
I set the aircraft up again then did the throttle back to idle thing.
as the power came off the tailwind put its nose down and entered an
increasingly steepening turn to the right. I called it quits at that
stage rather than have to walk home some 200 km.
The turn is to be expected because of the rudder offset.
Interesting. I didnt realise that the aircraft would be that stable if
you held the rudder still.
what michael (i think it was he) claimed regarding power off
instability seems correct if the aircraft has no inherent stability.
I think he overstates the tendency to instability for something with
dihedral like the cessna 150 or piper 140. I'd would be interesting to
try it in one of those aircraft.
Stealth Pilot
have vanished off my free agent.
I experimented in the Tailwind on sunday to see what occurs on power
off.
now mind you the Tailwind isnt the usual FAR23 aircraft. It has no
dihedral, neutral stability and not much inertia. it is however a dead
honest airframe.
I tried the suggestion regarding spiral instability while tootling
over to Cape Naturaliste.
If I set up the tailwind in balanced straight and level flight and
take the hands and feet off everything the aircraft dives off in a
spiral, which you'd expect from a neutrally stable aircraft
encountering a gust.
I tried setting everything up in balance then held my feet still on
the rudders, hands off everything else. the aircraft flew with slight
deviations in almost straight and level flight for 10 minutes or so.
It showed no tendency toward instability which I must say surprised
me.
I then ran out of country and turned around back toward Busselton.
I set the aircraft up again then did the throttle back to idle thing.
as the power came off the tailwind put its nose down and entered an
increasingly steepening turn to the right. I called it quits at that
stage rather than have to walk home some 200 km.
The turn is to be expected because of the rudder offset.
Interesting. I didnt realise that the aircraft would be that stable if
you held the rudder still.
what michael (i think it was he) claimed regarding power off
instability seems correct if the aircraft has no inherent stability.
I think he overstates the tendency to instability for something with
dihedral like the cessna 150 or piper 140. I'd would be interesting to
try it in one of those aircraft.
Stealth Pilot