Doors popping open in flight

On Wed, 31 May 2006 07:21:50 -0500, (Jay Masino)
wrote:

Roger wrote:
Just remember that door is a structural member in the Arrow, unlike
the Cessna.


The door opening *frame* may be a structural member, but not the door itself.
I doubt there's any significant cockpit strength difference when the door is
latched vs. unlatched.

Consider this.
Open the door in level flight. Now close the door in level flight. It
won't close. Why? If you look, the door shape no longer matches that
of the opening. As I recall on the Cherokee 180 the mismatch was on
the order of half an inch. That means the fuselage flexed about a half
an inch. The door was providing additional, structural strength
albeit it's not critical.

On a Bonanza the mismatch is even more. It's enough that you are not
going to close that door in level flight or without unloading the
airframe which can be done but I doubt it'd be considered a "normal"
maneuver.

On both planes the door is considered part of the structure. It's
just not a critical part of the structure.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


--- Jay

Roger,

If you look, the door shape no longer matches that
of the opening.


Please, look again.

--
Thomas Borchert (EDDH)

Roger wrote:

Open the door in level flight. Now close the door in level flight. It
won't close. Why? If you look, the door shape no longer matches that
of the opening. As I recall on the Cherokee 180 the mismatch was on
the order of half an inch.

The (4) PA-28 airframes I've flown (mostly 160HP Warriors) will close
quite easily if you follow the POH in-flight door closing procedure.
With the storm window open, cabin vents closed, and the right airspeed,
the door is almost sucked closed.

Was there something wrong with the Cherokee you were flying? G

Roger wrote:
Consider this.
Open the door in level flight. Now close the door in level flight. It
won't close. Why? If you look, the door shape no longer matches that
of the opening. As I recall on the Cherokee 180 the mismatch was on
the order of half an inch. That means the fuselage flexed about a half
an inch. The door was providing additional, structural strength
albeit it's not critical.


I think you're making a wrong assumption. Look at the door, the hinges, and
the latches. There's nothing strong enough to be considered "structural".
The door frame flexes a bit. When you have the door latched securely, first,
the gap remains small. If the door frame flexes a bit, while the door is
open, there's little hope of getting the door to shut as securely.

--- Jay


--

Jay Masino "Home is where the critters are"
http://www.JayMasino.com
http://www.OceanCityAirport.com
http://www.oc-Adolfos.com