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Ed et al: Re step--rather than fighting the aero forces, I suggest you consider controlling them. I have watched many frustrated LIV drivers try, try again and then wire their step closed. I agree it is the air pushing the step closed, so I taped an air "trip, Gurney flap" on the underside of the horz portion of the step and that has solved my problem. It is just a bent piece of alum that adds a sharp edge pointed down so a vacuum is created that helps the step extend. The trip could also be added to the front edge of the spanwise well into which the step retracts--anything to disturb the flow and create a low pressure area.
Oh, and another suggestion re: air conditioning--do not pressurize your LIV when building. My aft fan is all I need on the gnd and ambient temp is plenty when airborne. You pressurization folks are fighting turbo air that gets above 140 F when the system is working hard (check your induction temp). Sorry--I have no self control...
Paul, cool N94PT with O2
-----Original Message-----
From: Janie & Ed Smith <2luv2fly@cox.net>
To: lml@lancaironline.net
Sent: Wed, Jul 15, 2009 9:47 am
Subject: [LML] Retractable Step IV-P
"I've done it alone many times, several times just trying to figure a way to make the "retractable" step actually work, before I finally gave up and disconnected the cable and just locked it down."
John,
T
he retractable step has been quite an "opportunity" for us as well. They certainly didn't put their "best man" on the engineering and design for the step.
There are many reasons why the step doesn't work, but the main reason ours didn't extend with the gear was because the spring just didn't seem to be quite strong enough to overcome the resistance of the aerodynamics under the wing. I felt like the air flow under the wing was a contributor to the step staying in the retracted position because every time we put the airplane on jacks and cycled the gear - everything worked perfectly! The step would fall down and only take a "nudge" to get it into the locked position. My thoughts were that the wind load would push it to the down & locked position, so I concentrated on getting the step to make that initial movement to the down position.
I found a company in Norfolk, VA that specializes in custom springs and I had them make a spring for me that was about 30% stronger. Right away, we noticed an improvement because the step would extend, but only at about 100 kts. Anything above that speed resulted in the step being on the wrong side of the gear. Eventually, after 4 tries of different spring sizes, we now have a step that extend @ 140 kts - just about every time. The only down side to all of this is that the custom one-of-a-kind springs cost $40. each. Of course, i
n the whole scheme of things - that is a small cost for the convenience of having a step. Like the A/C that Jeff was talking about - - it sure is nice and Janie (better half) likes it, so there "ain't" no problem with the cost!! <grin> You know the old story about Mamma being happy!
Tailwinds,
Ed Smith
N9JE
Chesapeake, VA
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