From: Danny Miller <danny.miller@verizon.net>
Subject: [LML] Re: 360 carbon/racing gear doors
To: lml@lancaironline.net
Date: Sunday, April 17, 2011, 11:13 AM

Louis,

You’re not alone in these questions.  If answers and comments come to you directly rather than through LML, please share.

 

Danny Miller

N 38° 43' 25.7"

W 77° 30' 38.6"

 

From: Louis Gabriel [mailto:louis@gabriels.us]
Sent: Saturday, April 16, 2011 8:24 PM
To: lml@lancaironline.net
Subject: 360 carbon/racing gear doors

 

First, thanks for being such a great community--I'm brand new to both general aviation and the Lancair game, and I have never encountered a more patient and willing-to-answer-dumb-questions bunch.  I was hoping you might oblige me once more:

I am a new owner of a Lancair 360 Mk II with outback gear...and I've been plagued with gear door problems.  None of these are new or unsolved, but almost every piece of advice on the LML and otherwise (namely n91cz.com) suggests the solution is a set of three-piece, carbon fiber gear doors.

Where do they come from?  How do I get a set?

For some (perhaps unnecessary) background, here are the problems I'm having:
1. Inner gear door flutter.  When the gear is extended, the inner gear doors move around quite a bit in the prop wash (wearing out the hinge pin).  I've mostly solved this by replacing the flimsy aluminum hinge with stainless steel, but I still have some qualms about the permanence of my solution.

2. High speed buffet.  I've found that the trailing edge of my left inner gear door does not hold very effectively against either the airframe or the outer door, which above about 180 kts will occasionally start to buffet and buzz rather alarmingly.  After determining this noise was not the imminent end of my flying career, I found slowing down, cycling the gear (just enough to reseat the inner doors), then speeding back up solved my problem.  Upon swinging the gear, it's apparent the trailing edge of the inner gear door is the issue.

3. Drag.  Even on the jack stands, there is quite a bit of undercarriage material in the otherwise undisturbed slipstream.

Here are my thoughts on potential solutions:
1. To solve the inner gear door flutter issue, I should first minimize the amount of inner gear door I have.  The three-piece carbon set does just that, according to my understanding.  I'd like to start there.  Second, I can fiddle around with the hinge system further, but what I would REALLY like to do is sequence the doors to close after the gear is down.  I plan on doing instrument work--it would be nice to be able to drag the gear whenever I want without thinking about the doors.  Has anyone experimented with this?

2. For the rest of my problems, stiffer, smaller, better-designed doors are the answer.  My only hurdle is acquiring them--and that's where I'm hoping for your help.

Thanks for your time, and I really appreciate your help.  I'm glad to be part of the community!

Louis Gabriel
N61GH, KCVN