X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 06 Sep 2012 08:15:35 -0400 Message-ID: X-Original-Return-Path: Received: from blu0-omc3-s12.blu0.hotmail.com ([65.55.116.87] verified) by logan.com (CommuniGate Pro SMTP 6.0c1) with ESMTP id 5746560 for lml@lancaironline.net; Wed, 05 Sep 2012 22:22:39 -0400 Received-SPF: neutral receiver=logan.com; client-ip=65.55.116.87; envelope-from=frederickmoreno@bigpond.com Received: from BLU0-SMTP248 ([65.55.116.74]) by blu0-omc3-s12.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 5 Sep 2012 19:22:05 -0700 X-Originating-IP: [58.168.81.167] X-EIP: [ZZwfoYGqhjhTXU71iNrm//vmzGtmAviH] X-Originating-Email: [frederickmoreno@bigpond.com] X-Original-Message-ID: X-Original-Return-Path: frederickmoreno@bigpond.com Received: from Razzle ([58.168.81.167]) by BLU0-SMTP248.blu0.hotmail.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Wed, 5 Sep 2012 19:22:03 -0700 MIME-Version: 1.0 X-Original-Date: Thu, 6 Sep 2012 10:21:43 +0800 Content-Type: multipart/alternative; charset="us-ascii"; boundary="------------Boundary-00=_78PWVW72QL8000000000" X-Mailer: IncrediMail (6295203) From: Frederick Moreno References: X-FID: FLAVOR00-NONE-0000-0000-000000000000 X-Priority: 3 X-Original-To: "Lancair Mail (lml@lancaironline.net)" Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure X-OriginalArrivalTime: 06 Sep 2012 02:22:04.0295 (UTC) FILETIME=[67B77170:01CD8BD6] --------------Boundary-00=_78PWVW72QL8000000000 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Colyn wrote:.=0D =0D =0D I suspect they are effective down to a lower speed than precise-flights though?=0D Could be useful for spot landings on short final to a hay field?=0D =0D My speed brake effect is greatly diminished at lower speeds, but rises ag= ain as the angle of attack begins to rise, in the form of higher sink rate. S= o during my recent BFR when the instructor wanted to see a series of "force= d landing" I made the customary approach over the airport and then a descending 270 degree circle approach to the runway adjusting radius to g= et the desired outcome. =0D =0D We found that the speed brakes could be used with good effectiveness to provide a second adjustment (besides adjusting radius), increase of sink rate and thus descent angle, during the final stages of approach. You ca= n also leave them out and flare as long as you are operating with 120 knots which is my forced landing best glide speed anyway. So a secondary bene= fit with the speed brakes that others might try is to aim for 35-50% of the w= ay down the runway initially during forced landing practice, and then shorte= n the approach at the end with application of speed brakes. =0D =0D Y'll be careful out there, y'hear!=0D =0D Fred=0D =0D =0D On Sep 4, 2012, at 11:16 PM, Frederick Moreno wrote:=0D =0D =0D Colyn wrote: Tell us more about those hydraulic speed brakes...=0D =0D =0D A flap hydraulic cylinder is mounted cross wise on the back of the main s= par and pushes and pulls a bell crank that pushes and pulls two heavy duty marine grade push pull cables that then snake out through the fuselage an= d out to the speed brakes. The whole assembly sits under the pilot and copilot seats, and is covered by a molded carbon cover to keep back seat passenger feet from getting involved. The cylinder is operated by the sa= me type of valve used for flap actuation. The valve is located in the cen= ter vertical console panel between but below the gear and flap handles and ha= s its own unique knob.=0D =0D The push pull cables terminate in a four bar linkage in each wing that serves two purposes. First the horizontal motion of the cable is conver= ted to vertical motion which pushes the speed brake panels up and down. The panels are in the conventional position, hinged at the front with a carbo= n piano hinge covered with a glider gap seal, and are about 18 inches wide = and 3.5 inches in the flow direction. They move up 45 degrees,and position = can be controlled just like flaps. The four bar linkage is also configured s= o that in the down position the panels are locked down by an over center movement so they can not float up, a common problem with some Precise-Flight speed brakes in turbulence. =0D =0D Overall they work about the same as the Precise-Flight speed brakes, but = are infinitely adjustable which turns out not to be much of an advantage. I either put them out or don't. And having a very tight fit on the top of = the wing, there is no leakage of air from inside the wing out the top of the wing which reduces drag a smidgen.=0D =0D It was a hell of a lot of design and fabrication work to save the price o= f Precise-flight brakes (which I never much liked) in favor of a hydraulic valve, cylinder, and some cables. Not recommended.=0D =0D Fred=0D =0D =0D =0D =0D =0D =20 --------------Boundary-00=_78PWVW72QL8000000000 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
Colyn wrote:.

I suspect they are effective down to a lower speed than precise-flig= hts though?
Could be useful for spot landings on short final to a hay field?
 
My speed brake effect is greatly diminished at lower speeds, but ris= es again as the angle of attack begins to rise, in the form of higher sin= k rate. So during my recent BFR when the instructor wanted to see a serie= s of "forced landing" I made the customary approach over the airport and = then a descending 270 degree circle approach to the runway adjusting radi= us to get the desired outcome. 
 
We found that the speed brakes could be used with good effectiveness= to provide a second adjustment (besides adjusting  radius), increas= e of sink rate and thus descent angle, during the final stages of approac= h.  You can also leave them out and flare as long as you are operati= ng with 120 knots which is my forced landing best glide speed anyway.&nbs= p;  So a secondary benefit with the speed brakes that others might t= ry is to aim for 35-50% of the way down the runway initially during force= d landing practice, and then shorten the approach at the end with applica= tion of speed brakes. 
 
Y'll be careful out there, y'hear!
 
Fred

On Sep 4, 2012, at 11:16 PM, Frederick Moreno wrote:

 Colyn wrote: Tell us more about those hydraulic speed brakes..= =2E

A flap hydraulic cylinder is mounted cross wise on the back of the m= ain spar and pushes and pulls a bell crank that pushes and pulls two heav= y duty marine grade push pull cables that then snake out through the fuse= lage and out to the speed brakes.  The whole assembly sits unde= r the pilot and copilot seats, and is covered by a molded carbon cov= er to keep back seat passenger feet from getting involved. &nbs= p;The cylinder is operated by the same type of valve  used for = flap actuation.   The valve is located in the center vertical c= onsole panel between but below the gear and flap handles and has its own = unique knob.
 
The push pull cables terminate in a four bar linkage in each wing th= at serves two purposes.   First the horizontal motion of the ca= ble is converted to vertical motion which pushes the speed brake panels u= p and down.   The panels are in the conventional position, hing= ed at the front with a carbon piano hinge covered with a glider gap seal,= and are about 18 inches wide and 3.5 inches in the flow direction. =   They move up 45 degrees,and position can be controlled just like f= laps.  The four bar linkage is also configured so that in the down p= osition the panels are locked down by an over center movement so they can=   not float up, a common problem with some Precise-Flight speed brak= es in turbulence. 
 
Overall they work about the same as the Precise-Flight speed brakes,= but are infinitely adjustable which  turns out not to be much of an= advantage.  I either put them out or don't.  And having a= very tight fit on the top of the wing, there is no leakage of air from i= nside the wing out the top of the wing which reduces drag a smidgen.
 
It was a hell of a lot of design and fabrication work to save the pr= ice of Precise-flight brakes (which I never much liked) in favor of a hyd= raulic valve, cylinder, and some cables.  Not recommended.
 
Fred

 
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