X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 18 Jun 2014 07:30:38 -0400 Message-ID: X-Original-Return-Path: Received: from rc5-smtp.comporium.net ([208.104.2.19] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTP id 6939103 for lml@lancaironline.net; Wed, 18 Jun 2014 07:16:50 -0400 Received-SPF: pass receiver=logan.com; client-ip=208.104.2.19; envelope-from=snopercod@comporium.net Received: from rg25.comporium.net ([208.104.244.60]) by rc5-smtp.comporium.net ({548c1f54-a96b-4a18-a171-d2818e6ccf4d}) via TCP (outbound) with ESMTP id 20140618111615977 for ; Wed, 18 Jun 2014 11:16:15 +0000 X-RC-FROM: X-RC-RCPT: Received: from 33.225.235.68.dsl.brvdnc.dynamic.citcom.Net (EHLO _127.0.0.1_) ([68.235.225.33]) by rg24.comporium.net (MOS 4.3.4-GA FastPath queued) with ESMTP id RTM58198 (AUTH snopercod); Wed, 18 Jun 2014 07:16:15 -0400 (EDT) X-Original-Message-ID: <53A174F8.7040708@comporium.net> X-Original-Date: Wed, 18 Jun 2014 07:16:08 -0400 From: John Cooper User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: Legacy flap buzz above 160kts References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------000109050008090002040606" X-MAG-OUTBOUND: comporium.redcondor.net@208.104.244.48/28 This is a multi-part message in MIME format. --------------000109050008090002040606 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Clarence Grubbs had a similar problem in his L-235 and it turned out to be the gap seals on the bottom of his flaps. (The flaps were hinged on the top in the L-235.) I don't recall how he fixed the problem. --John On 6/18/2014 6:01 AM, Lancair Mailing List wrote: > Subject: > Legacy flap buzz above 160kts > From: > "Adam Molny" > Date: > 6/17/2014 4:07 PM > > > I have had this problem intermittently for the past year or so, but > now it is becoming a regular occurrence. When I go above 160KIAS I get > a loud buzzing sound throughout the airframe. I cannot feel it through > the control stick. I can make the buzz stop by loading the wing > slightly with g's or by extending the flaps about ¾". > > There is a line of rub marks on the top side of the flaps where they > meet the trailing edge wing skin. I initially thought the skin was > vibrating since it is fairly flexible there, but now I'm not so sure. > If I partially extend the flaps on the ground I can feel a fair amount > of up-and-down play in the flap hinges. I haven't had a chance to > disassemble the hinge pin yet. > > Has anyone else had this problem? If so, what was the cause and how > did you fix it? > --------------000109050008090002040606 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit

Clarence Grubbs had a similar problem in his L-235 and it turned out to be the gap seals on the bottom of his flaps. (The flaps were hinged on the top in the L-235.) I don't recall how he fixed the problem.

--John

On 6/18/2014 6:01 AM, Lancair Mailing List wrote:

Subject:
Legacy flap buzz above 160kts

From:
"Adam Molny" <Adam@ValidationPartners.com>

Date:
6/17/2014 4:07 PM

I have had this problem intermittently for the past year or so, but now it is becoming a regular occurrence. When I go above 160KIAS I get a loud buzzing sound throughout the airframe. I cannot feel it through the control stick. I can make the buzz stop by loading the wing slightly with g’s or by extending the flaps about ¾”.

There is a line of rub marks on the top side of the flaps where they meet the trailing edge wing skin. I initially thought the skin was vibrating since it is fairly flexible there, but now I’m not so sure. If I partially extend the flaps on the ground I can feel a fair amount of up-and-down play in the flap hinges. I haven’t had a chance to disassemble the hinge pin yet.

Has anyone else had this problem? If so, what was the cause and how did you fix it?

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