REFLECTOR: barn door speed brake

Mon Oct 16 17:34:16 CDT 2006

I'm thinking that a "half" size speed brake for RG models, with a higher 
deployment speed, might be a drag option for enroute descents.
Anyone else have thoughts on this?
SB

----- Original Message ----- 
From: "Terry Miles" <terrence_miles at hotmail.com>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Monday, October 16, 2006 8:55 AM
Subject: Re: REFLECTOR: barn door speed brake

> John,
>
> Thanks for the comprehensive reply on the SB issues.  It sounds like our
> situations are similar.  To add to your knowledge base, and as best I
> recall the conversation with Scott Baker, the factory encourages the
> "all or none" on speed brake deployment, but I too have a momentary "on"
> for the deploy side and will probably count in my head over having a
> gauge showing degree of deployment, but that's a good idea.
>
> I also asked SB, and I would guess many have before me, on the notion
> about lessor angle ought to mean higher speed limit.  Baker declined to
> speculate, and added a warning to me about the panel going thru the prop
> if the envelope was pushed beyond tolerance.  He did mention no attempt
> was made by Velocity to test the high end of the speed range for the SB.
> As I recall it he said that they decided 110 was safe and pegged it at
> that.  ...or you might say a traffic pattern speed control device and
> not designed for arrival descent use, or ATC requests to increase rate
> of descent.
>
> Terry
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Paula & John Schoorl
> Sent: Thursday, October 12, 2006 12:50 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: barn door speed brake
>
>
> Terry:
> Too add a little more info to Craig's reply about our XL-5FG with speed
> brake:
> Our max extension angle is about 75 degrees.  Chap 14 recommends not to
> exceed 60 degrees.  How we ended up that way was we converted to the
> cutdown keel halfway through the build and had to adjust our actuator
> position to make it work.  It resulted in more extension angle than we
> originally had. It also resulted in the actuator being installed in a
> nearly vertical position which makes for a not very good load path from
> door through actuator to keel.  On my to do list is to do the math and
> figure what loads our actuator is seeing in our configuration versus the
> book installation.
>
> Our test pilot likes to fly his final approach with the speed brake
> extended so he can keep more power in and have better engine response.
> I tried the same technique but was not very comfortable with it and my
> landings showed that.  I went back to flying without it like I was
> primarly taught at the factory and my landings improved greatly.  Once I
> am more comfortable in the airplane I will probably go back and
> experiment with the speed brake some more, especially to shorten landing
> distance.
>
> As a side note to the discussion about rapid descents with gear or
> brakes
> extended:  The factory airplane wires the speed brake so it is either
> fully extended of fully retracted.  I assume this air load on the door
> and into the actuator and keel is what drives the 110kts speed brake
> limitation. Craig and I wired our speed brake so the brake only extends
> while you hold the switch down so we can extend to any angle we want by
> how long we hold the switch (we have a position indicator on the panel).
> Flip the switch up and the brake retracts completely for a go-around, in
> case your wondering. While I'm figuring out loads on the brake, I also
> intend to look at whether I can get away with a shallower speed brake
> angle at a higher speed than 110 and get the benefit of the drag for a
> higher rate of descent.  Thats an engineering problem for down the road
> if I don't convince myself its a bad idea before then.
>
> Hope that wasn't too much information....
> John Schoorl
> XL-5FG
> Palmdale, CA
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Terry Miles
> Sent: Wednesday, October 11, 2006 1:31 PM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: barn door speed brake
>
>
> Thanks you guys.  ...and thanks Jorge.  The only one I could half way
> measure looked to be between 55 to 60. Terry
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Craig and/or Denise Woolston
> Sent: Wednesday, October 11, 2006 8:32 AM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: barn door speed brake
>
>
> I'd say our extension angle is around 60 degrees.  I honestly can't
> remember right now if the manual said to limit it or not.  The test
> pilot landed with it down every time, but I haven't used it yet.
>
> Craig
> XL-5FG Flying in Palmdale, CA
>
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
> _______________________________________________
> To change your email address, visit 
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html 