REFLECTOR: barn door speed brake
Chuck Jensen
cjensen at dts9000.com
Mon Oct 9 10:10:53 CDT 2006
Scott,
Good points all. Yes, most of the eastern 2/3rds of the country does do
flat lander flying, though there are instances in the summer, when
anything below 7,500 agl can be unnecessarily bumpy. In those
instances, damn the efficiency--expedited descents to minimize stay-time
in the less pleasant low altitude environment is in order. I've never
grown accustomed to and learned to enjoy turbulence.
With rare exceptions over the Appy Chain, we just don't see the up/down
drafts that you encounter in mountain flying out west, though there are
days that being above 10,000' over the Smokies is a smooth idea.
Chuck Jensen
Do Not Archive
-----Original Message-----
From: reflector-bounces at tvbf.org
[mailto:reflector-bounces at tvbf.org] On Behalf Of Scott Derrick
Sent: Monday, October 09, 2006 10:13 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: barn door speed brake
You guys must all fly in flat land smooth air. And never fly
into big airports where you do what ATC says or you go somewhere else,
and its not because they are *** holes, its because they need it to keep
from bending aluminum..
In the mountain west getting down can be a real chore. The
problem is mostly in the summer but if windy can be any time of year.
I've had to throw the gear out on that Centurion to maintain altitude,
much less think about descending.
Descending in normal everyday summer turbulence in New Mexico
or Arizona or Colorado or Wyoming or Utah or Nevada or Eastern
California or Idaho at 500 fpm in our airplane requires more than
pulling a few inches of MAP and pointing the nose down. On many days
you do that and I hope you and your passengers are wearing crash
helmets. Its also a good way to verify that +12, -9 G airframe you
built. Just flying along at a cruise of 150 to 180 KIAS is bumpy
enough, increase the airspeed 20 or 30 knots and you are deep into the
yellow arc on the airspeed indicator. The seat belt starts to become
very uncomfortable.
Sure 500 fpm is the normal descent rate into an uncontrolled
field, if traffic, terrain and turbulence allows.
Problem is when your battling thermal and orographic turbulence
the main weapon is to fly as high as you can. Winter I fly as low as I
can. I love flying 500 agl from ABQ to TVL! But in the summer you'll
find me at 17,500 trying to stay in smooth air. Now when you are
approaching your destination you have a choice, slow down way out for
a long bumpy leisurely descent or stay up high as long as possible and
come down fast. This of course assumes you have passengers that know how
to breath for a 1000 fpm descent, if its just me I'll do a 2000 fpm
descent, coming from 17,500 to 7500 pattern altitude there is a
difference of up to 20+ minutes of a painful bumpy ride or less than 5
minutes of bumps, you do the math.
No matter how you look at it, a slick airplane needs a way to
come down with more control than the velocity has. I've flown
Bonanza's, Mooneys, Turbo Arrows, Turbo Centurions. I flew a Mooney
with speed brakes, it was a joy to descend, I knew no matter what
situation I was in I could handle it with out beating up the airplane or
the occupants, the Centurion with 165 knot gear extension is the same
way. Once you fly an airplane with that capability you wonder why ours
is so deficient.
Scott
Chuck Jensen wrote:
A strong reason for a 500fpm planned descent is
efficiency and economy. We spend a lot of fuel/speed/time to gain
altitude. It's a terrible waste to not turn that 'potential energy'
into higher speed and reduced fuel consumption during descent. If VFR,
a 200-300 fpm descent rates seems to be the most productive. If IFR,
unless ATC puts us in a squeeze, we can work with a 500 fpm descent,
which is still pretty efficient.
In contrast, throw out the barn door for a rapid descent
and that long slow climb and 100LL liquid gold disappears as turbulent
drag with no gain in speed or economy.
Chuck Jensen
-----Original Message-----
From: reflector-bounces at tvbf.org
[mailto:reflector-bounces at tvbf.org] On Behalf Of Richard J. Gentil
Sent: Monday, October 09, 2006 8:54 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: barn door speed brake
I would think that unpressurized, you climb as
fast as you want but you come down on average, at 500fpm. Much more then
that and you start hurting the Pax ears. Most of the time I will start
screaming for lower a couple minutes before I end up at the 2 minutes
from destination for every 1,000ft I am AGL.
Since I have yet to fly a Velo, anyone know in
an SE RG what speed indicated you hit when you keep cruise power (65%)
and a 500fpm descent rate?
Richard
P.S. Scott, I never thought about the fact, wing
speed breaks also destroy lift, not an option.
Chuck Jensen wrote:
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
________________________________
_______________________________________________
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
--
-
As nightfall does not come at once,
neither does oppression. In both instances, there is a twilight when
everything remains seemingly unchanged. And it is in such twilight that
we all must be most aware of change in the air however slight lest we
become unwitting victims of the darkness.
William O. Douglas, Justice of the
U.S. Supreme Court
________________________________
_______________________________________________
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
________________________________
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.407 / Virus Database:
268.13.1/466 - Release Date: 10/7/2006
________________________________
_______________________________________________
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
--
-
As nightfall does not come at once, neither does oppression.
In both instances, there is a twilight when everything remains seemingly
unchanged. And it is in such twilight that we all must be most aware of
change in the air however slight lest we become unwitting victims of the
darkness.
William O. Douglas, Justice of the U.S. Supreme Court
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20061009/851968ef/attachment.html
More information about the Reflector
mailing list