REFLECTOR: Speed Brake Construction Question

[Brian Michalk]

Ahh, the joys of measuring things.

At work, a geophysicist once said (when referring to geophones), "Always
take the first reading, because after that, you'll just get confused."

Two issues; logitudinal reference, and transverse reference.  Were do you
calculate your centerline to be?  Where did Velocity calculate it to be?
I'm not sure if this is still the case, but my fuselage, like many its age
is banana shaped.  This throws lots of things off center.  Most of them I am
the only one who can tell.

Attach to the speed brake panel where it is structurally correct for the
speedbrake.  This means your actuator will not be mounted in the center of
the keel.  No problem, because It might even be a good thing if you want to
run something else in there.  Make sure this arrangement will not affect
your RG hardware (Mines FG, so I didn't care).  You may have to mount the
actuator at an angle.

In the end, all that matters is that your canard and wings are square, and
reasonably square to the fuselage.  Of course, it's important that your
landing gear be square as well, but not necessarily square with your wings.

On mine, I installed the firewall per plans.  When I installed the main
spar, I found I needed .25" shim (I think) on the copilot side.

 Brian Michalk  <http://www.michalk.com>
Life is what you make of it ... never wish you had done something.
Aviator, experimental aircraft builder, motorcyclist, SCUBA diver
musician, home-brewer, entrepreneur and barely single

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Randy Wharton
Sent: Sunday, August 08, 2004 12:44 PM
To: reflector at tvbf.org
Subject: REFLECTOR: Speed Brake Construction Question


First of all, thanks for everyone’s input on whether or not I should put a
speed brake in my XL-RG. After considering everyone’s input, I decided that
I’d rather have it and not need it than need it and not have it, so I’m
working on putting it in now.

Almost immediately I have run across into something I’m not sure of, so if
anyone can help out, I’d appreciate it. The hard point for the actuator on
the speed brake itself is clearly shown in the manual to center
(longitudinally) at 8” forward of the trailing edge and offset ½” to the
starboard side. No problem. However, the speed brake already has a hard
point in it from the factory, but it’s not where they say I need to have it;
it’s about 2” too far forward.

Is the measurement in the manual wrong? The diagram in the manual shows the
hard point maybe 1.5 inches from the leading edge, which is where the hard
point seems to be, but the measurement I’m given to go by is 8” from the
trailing edge. I’ve put a photo on my website to show what my speed brake
looks like with the supposed hard point location marked on it, and you can
see the relationship with the hard point already there from the factory. The
photo is at http://cisweb.owens.edu/~rwharton/Velocity/speedbrake.jpg . The
installed hard point is also about a half inch to the port side of where the
manual calls for it. Maybe this is not the speed brake hard point, but a
seat hard point?

At any rate, has anyone got experience with this little anomaly? Sure I can
call the factory tomorrow, but it’s the weekend and I’m building!!!

Randy and Becky Wharton
N248RB - Velocity XL-RG
http://clik.to/velocity