REFLECTOR: barn door speed brake

Tom Martino tmartino at troubleshooter.com
Mon Oct 9 08:22:30 CDT 2006


I did tests with and without gear doors.  I found maybe a 2 to 3 knot
difference.  But since I usually have to "pull it back" to avoid Vne ...
or for turbulence ... I did not see a reason for the doors to begin
with.  

 

I have successfully deployed gear at 135 knots (TAS).  Not adverse
effects.  The gear is an excellent speed brake.  However, I still use
the brake at the bottom of the fuselage when I want a steeper descent
without building up too much speed.

 

Tom

 

________________________________

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chuck Jensen
Sent: Monday, October 09, 2006 6:22 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: barn door speed brake

 

It would be nice to extend gear above 110 kts, though I'm sure some have
done so and I've yet to hear of anyone slicing-n-dicing their departing
gear doors.  The gear door extension speed for the Velocity may be much
like the Vne....it's a number, and I've not heard conclusive evidence
that it is anything but just a number, so it may be a suggestion, not a
limit.

 

As far as shock cooling of the engine, Scott, if you're descending 2000
fpm in the Centurion and you're not shock cooling the engine, exactly
how fast did you intend dive the Velo such that you could shock cool the
engine?  I thought that OWT had been put to bed, unless you're flying a
radial or a couple other odd ball engines.  If we reduce MP a few inches
and point it down with the gear tucked, we might want to watch Vne,
especially in turbulence. but engine cooling can be put way down the
list.

 

As far as ATC giving you a slam-dunk approach, that can be solved with
one word, "unable".  However, as Ken reported, the speed board does seem
to cushion the nose gear 'plop' on touch-down...now that would be
appreciated!

Chuck Jensen 
  

	-----Original Message-----
	From: reflector-bounces at tvbf.org
[mailto:reflector-bounces at tvbf.org] On Behalf Of Scott Derrick
	Sent: Sunday, October 08, 2006 5:33 PM
	To: Velocity Aircraft Owners and Builders list
	Subject: Re: REFLECTOR: barn door speed brake

	What's really needed is a high speed speed brake.  The current
110 knot extension speed severely limits its usefulness.
	
	 The descent from altitude at cruise speed is where our airplane
can bite us.  If the air is turbulent or ATC would like a hurry up
descent the only option is the pull the throttle and shock cool the
engine. I fly a Centurion that has a 165 knot gear extension speed with
200 knots after its deployed.  Descending is a breeze, throw the gear
out and your descending at 1500 ft per minute with no increase in
airspeed and you just leave the throttle alone, reduce 3 or 4 inches of
manifold pressure and your descending at 2000 ft per minute and the
engine cools down nice and slow...
	
	Scott
	
	Scott Baker wrote: 

	I don't know of anyone who has installed speed brakes in the
wings.

	This type of speed brake kills lift in additional to being a
drag device.

	Killing lift on the main wings invites a deep stall when the
aircraft gets slow.

	Installing an in-wing speed brake in the canard guards against a
deep stall, but it will also increase the stall speed.  Again, not a
good thing when the aircraft gets slow.

	I think a better approach is to look at additional drag devices
that deploy from the top of the fuselage - or - maybe a panel that
deploys from the nose gear area on RG models.

	SB

		----- Original Message ----- 

		From: Richard J. Gentil
<mailto:richard at naples-air-center.com>  

		To: Velocity Aircraft Owners and Builders list
<mailto:reflector at tvbf.org>  

		Sent: Sunday, October 08, 2006 2:54 PM

		Subject: Re: REFLECTOR: barn door speed brake

		 

		Scott,
		
		Has anyone done a speed brake system in the Velo wings?
		
		Richard
		
		Scott Baker wrote: 

		Plan on installing a speed-brake in all FG models,
especially when operating with a fixed pitch propeller.

		SB

	
	
	
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