Re: New Door Pivots

[ncalvin@primenet.com (nate calvin)]

>X-Sender: markm@mail.psyber.com
>Date: Sat, 04 Jul 1998 09:30:30 -0700
>To: ncalvin@primenet.com (nate calvin)
>From: Mark Machado <markm@psyber.com>
>Subject: Re: New Door Pivots
>X-UIDL: edadabf3c00779c1c2889e0b3bf52cc2
>
>Nate:
>
>Finished installing your new door pivots yesterday.  First impressions are
>favorable.  A few comments:
>
>1.  The action of the door is definitely different.  Rather than being a
>constant pressure up when you unlatch the door, due to the overcenter
>nature of the offset hinge bracket, you must actually lift the door
>somewhat before the mechanical advantage and the force of the gas strut
>takes over. One of my typical proceedures is to reach through the pilot's
>door, unlatch the co-pilot's door, give a slight push, thus allowing the
>door to open (at least half way).  With your system, my first impression is
>I'll need to change my style.  Of course I've only tried it with an XL,
>where you quickly run out of arm length/leverage.
>
>2.  This overcenter nature of the system actually will slam the door shut
>should you not be paying attention. If the door latching pins happen to be
>extended out any amount (accidentially or on purpose), damage to the
>finished paint on the fuselage will result.  Quite frankly, this is a
>common problem with our demo planes where unsupervised people are moving
>the doors through their motion and simultaneously playing with the door
>handles.
>
>3.  If you are aware of the positive closing nature of the system, this can
>actually help you in closing the doors.  In addition, since the strut is
>shorter than what is provided in the kits, the strut can be mounted at more
>of a right angle to the door hinge line, which eliminates the adverse
>torqueing of the door as it closes.
>
>4.  With the strut pressure being directed more towards the door hinge
>line, when the door is closed, this essentially eliminates the bulge in the
>fuselage wall, which must be dealt with during the filling and sanding
>phase of the construction.
>
>5.  Due to the increased force of the strut (the kit supplied gas struts
>are worth about 60-90 lbs of force whereas the one you provide I would
>guess are in the 120 lbs range), an aluminum hardpoint, at the attach point
>in the carbon beam, would be recommended.
>
>6.  From a retrofit standpoint, several things should be considered. In
>some cases there may be interference with your bracket and the top fuselage
>door lip (and/or weatherseal material) as the door closes.  Also, the exact
>mounting position of the strut to the carbon beam (on the forward edge or
>the inside face) may have to be adjusted to accommodate an interference
>with seatbelt hardware.  In our case here, a custom carbon beam mounted
>interia reel necessitated a repositioning of the mounting point.  Finally,
>if you have finsihed your upholstery, you'll have to deal with a hole in
>your fabric where the old strut originally attached.    
>
>Summary:  Without a doubt, the doors shut easier.  On the otherhand, you
>don't get something for nothing.  Because they shut easier, they are
>slightly harder/heavier to open. My personal opinion is it's worth the
>disadvantage.  Bottom line.........send me another set!
>
>Take Care
>Mark
>Velocity West
>
>
>P.S. Rather than send the old ball pivots out to a machine shop to have
>them turned down to a small diameter, we "chuck'd" them up in a drill
>press, turned it on and worked a file against the ball until the proper
>diameter was achieved.  Maybe 2-3 minutes per pivot.  Worked just fine.
>
>
>