REFLECTOR: Speed Brake

Wed Jul 14 14:24:44 CDT 2004

Sometimes making things automatic can bite you in the ass more easily than 
they can help you.

I think this is one of them.   I would not want the speed brake to 
automatically deploy or retract on me.

Scott

At 10:56 AM 7/14/2004, you wrote:
>xmlns="http://www.w3.org/TR/REC-html40" xmlns:o = 
>"urn:schemas-microsoft-com:office:office" xmlns:w = 
>"urn:schemas-microsoft-com:office:word">
>Good suggestion, Christopher.  Your comments made me consider how to take 
>it past the an alarm and to automate the retraction under this set of 
>conditions.  Routing the input that would be used for an alarm (i.e.. 
>micro switch, hall effect, or prox sensor on the throttle linkage) to a 
>DPDT relay could facilitate both an alarm and an automatic retraction of 
>the speed brake.  1 of the DPDT poles would be used to trigger the alarm, 
>the COM contact of the second pole is connected to the CB for the speed 
>brake, the NC relay contact is connected to the COM of the speed brake 
>switch, and the NO contact to the retract side of the speed brake 
>actuator.  When no alarm condition exists the speed brake switch will 
>control normally, if the alarm/relay is triggered the actuator is powered 
>to retract and when retracted the internal switch turns power off to the 
>motor.  When the throttle is retarded out of the alarm range, the speed 
>brake switch regains functionality.
>
>I hope I remember this when I start wiring my AC.
>
>Joe
>----- Original Message -----
>From: <mailto:christophercmartin at earthlink.net>Christopher Martin
>To: <mailto:reflector at tvbf.org>Velocity Aircraft Owners and Builders list 
>; <mailto:reflector at tvbf.org>Velocity Aircraft Owners and Builders list
>Sent: Wednesday, July 14, 2004 12:20 PM
>Subject: Re: REFLECTOR: Speed Brake
>
>I have watched this conversation with real interest and having flown my XL 
>RG almost 500 hours without one, I find myself very interested in the 
>potential for rapid decent to the airport without shock cooling the big 
>IO-540. The description posted of staying up at altitude and making a 
>rapid decent with the speed brake is a real advantage. Normally that sort 
>of procedure requires such a reduction in manifold pressure that you would 
>shock cool the engine badly. Probably in the area of 80 degrees F per 
>minute. Far beyond the normal factory limit of 50 and the preferred user 
>applied limit of 35. So, I find myself very interested in retrofitting the 
>speed brake into the plane. There is however, one little caveat that I 
>have not heard anyone mention and that is the control system necessary to 
>avoid "go arounds" or "touch and gos" with the speed brake deployed.
>
>I remember coming into Santa Monica airport on a July afternoon three 
>years ago and finding aircraft parts scattered all over and three parked 
>planes banged up. A fellow velocity pilot had crashed and, fortunately, he 
>and his wife walked away unscathed. His plane and three other planes were 
>the only causalities. His problem had been the deployed speed brake. He 
>was coming into a normal landing with a crosswind approach with speed 
>brake deployed. Just as he touched down he encountered wind shear and so, 
>attempted to do a go around. He powered up and tried to take off but with 
>his speed brake deployed and the shifting wind he was unable to gain 
>altitude. He took out three parked airplanes in the process. His later 
>remark was ,"if only I had remembered to retract the speed brake". So, in 
>my desire to now retrofit a speed brake into my ship. I need to also 
>install an alarm that enunciates if the speed brake is deployed and the 
>throttle is increased. Not to difficult to! do but a necessary addition in MHO.
>
>Chris
>
>Christopher Martin
><mailto:christophercmartin at earthlink.net>christophercmartin at earthlink.net
>
>
>
>----- Original Message -----
>From: <mailto:gpoole at zeta.org.au>Greg Poole
>To: <mailto:reflector at tvbf.org>Velocity Aircraft Owners and Builders list
>Sent: 7/15/2004 1:48:25 AM
>Subject: Re: REFLECTOR: Speed Brake
>
>Thanks for your sentiments Randy,
>
>Strange thing.....I find many aviators tend to express opinions to back 
>their own MO of having or not having a speed brake on their airplanes and 
>one is left in the middle quite confused.
>
>I don't particularly want to influence you one way or the other and have a 
>speed brake just for it's insurance value - both to protect whatever 
>constant speed prop I end up putting on, and to get down in a hurry if 
>ever I need to. I also like the idea of having such a gizmo to activate on 
>my aeroplane.
>
>...if ever you and Bec make it down this way - look us up!
>
>Kind regards,
>
>Greg. (DownUnder)
>Greg Poole
>[]
>
>Principal POOLED RESOURCES PTY LTD
>3 Cheltenham Close
>Castle Hill NSW 2154
><mailto:gregpoole at pacific.net.au>gregpoole at pacific.net.au
>tel:
>fax:
>mobile: (612) 9899 2737
>(612) 9899 2726
>0414 273199
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>----- Original Message -----
>From: <mailto:rwharton at buckeye-express.com>Randy Wharton
>To: <mailto:reflector at awpi.com>reflector at awpi.com
>Sent: Sunday, July 11, 2004 3:05 AM
>Subject: REFLECTOR: Speed Brake
>
>I'm new to the Reflector, so I hope this works!
>
>
>
>I have an XL-RG and I'm curious about the speed brake. It's marked on the 
>fuselage as "optional", and there is nothing in my manual about it. I 
>checked out the online manuals and found that the speed brake is only 
>addressed in the fixed gear models. I know that with retractable gear, the 
>gear down will act as a brake to some extent, but does anyone know of a 
>compelling reason why I should or should not install the speed brake?
>
>
>
>Randy and Becky Wharton
>
>N248RB - Velocity XL-RG
>
>http://clik.to/velocity
>
>
>
>
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