REFLECTOR: Wastegate Bellcrank & Max IO-550N Power
Bob Jackson
bobj at computer.org
Sun May 29 14:04:53 CDT 2011
Hello Alex,
That's the turbo manual wastegate bellcranck, with the cable from the manual
wastegate control knob on the instrument panel attached on the left, and the
cable going to the wastegate valve in the engine compartment attached on the
right side.
The wastegate valve cable only travels about 1" from fully open to fully
closed, so we're using the bellcrank with the center point 'offset' to
provide about 3" of throw for the instrument panel wastegate control, which
gives us a lot finer adjustment of the wastegate. Even as it is, I rarely
turn the wastegate control knob more than half a turn at a time because of
it's sensitivity in setting MAPs. There's also a lot of lag between setting
a new wastegate position and it's affect on MAP which makes it very hard to
set accurately and finely.
The position sensor mounted to the bellcrank tells us the wastegate position
in percentage from 0 to 100%. One reason we mounted the turbo bellcrank in
the cabin is so that eventually we can add a servo for automatic wastegate
control. The manual wastegate works great for turbo throttling, but it is
very high workload because of the sensitivity, and also because of overboost
concerns if mis-adjusted.
Takeoff wastegate position is 38%, which provides about 30.5" of MAP and
full engine power. I've only taken off once with the wastegate fully closed
by mistake (100%) and I saw about 36" MAP before I got it opened up again.
For high altitude airports like around Denver, takeoff wastegate position
increases to around 48%. We're only trying to turbonormalize, and I don't
think our standard IO-550N can take a lot more than the normal 310 hp for
very long before starting to show signs of 'stress'.
Does anyone have a good feel for what max continuous power an IO-550N should
be able to take without starting to come apart? We know we have some
'reserve power in the bag' with the turbo (for heavy takeoff weights and/or
high altitude airports), but we don't know how much. We're assuming we're
good to 350 to 360 hp for short periods on takeoff (assuming the TSIO-550C
and E's use the same engine block, pistons, crankshaft, bearings, etc.) but
don't really know how much for sure. Any expert knowledge and guidance
would be appreciated.
Bob
_____
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Alex Balic
Sent: Sunday, May 29, 2011 8:02 AM
To: bobj at jaxtechllc.com; 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Autopilot servos
Hey Bob-
What is that bellcrank mounted to the floor with the two white push pull
cables and position sensor mounted to it?
Alex
_____
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Bob Jackson (JaxTech)
Sent: Sunday, May 29, 2011 1:15 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Autopilot servos
Peter,
Here are two shots of our autopilot lateral servo installation - at the
time, it was the Blue Mtn servos, but we've since switched to TruTrak
servos, controlled by the GRT HX EFIS. Works great cruising and for coupled
approaches, including the TruTrak's auto-pitch trim controller. However,
rapid aircraft decelerations into the landing configuration from cruise
speeds can create situations where the TruTrak auto pitch trim can't keep up
with the trim changes required (and needs some manual help from the pilot).
This shot shows how the aileron AP servo (top center) ties into the aileron
torque arm, as seen from behind the whale tail of the keel.
Because of very limited space available in the rear cabin for electronics,
servos, etc., our aileron autopilot servo protrudes forward into the cabin
from the whale tail (shown with it's fiberglass cover), along with the ELT,
the cabin air exhaust port with servo controller, and the aileron trim motor
(with it's fiberglass cover)
Bob Jackson
N2XF
_____
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Peter Braswell
Sent: Saturday, May 28, 2011 3:36 PM
To: geoff.gerhardt at gmail.com; Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Autopilot servos
Geoff,
Sounds like you're making progress. I have the SV system + AP installed in
my Glastar and absolutely love it! Going to install the system in my
Velocity when it comes time which should be pretty cool. If you have any
pictures of the servo installation, I'd love to see ho you've ended up
mounting them.
Good luck,
Peter
--------------------------------------------------------------
Check out:
"It's a Jungle Up There": www.zuluworks.com
Selling your Airplane? : www.fly-mart.com
Great Aviation Gear: www.sky-gadgets.com
My blog: www.icekreamkoan.com
--------------------------------------------------------------
On Sat, May 28, 2011 at 1:19 PM, Geoff Gerhardt <geoff.gerhardt at gmail.com>
wrote:
Peter,
I found the torque adjustment - its set to 100%. After playing with it a
bit, the AP servo can control over a pretty good range before it has to be
re-trimmed. When the AP starts to sense a load, it notifies the pilot to
trim, and which direction to trim.
Thanks.
Geoff
On Sat, May 28, 2011 at 11:20 AM, Peter Braswell <peter.braswell at gmail.com>
wrote:
Geoff
There is a torque adjustment you can do in the set up and configuration menu
if you need it.
Peter
Sent from my iPhone
On May 28, 2011, at 9:51 AM, Geoff Gerhardt <geoff at thegerhardts.com> wrote:
Scott/John,
After playing with it a bit, and enabling altitude hold on the Dynon, I see
that it give messages to trim. Also, I ran the test procedure again with
the trim adjusted right in the middle, the AP ran the pitch servo up and
down over the relatively small range it uses to test successfully, so I
think its functioning normal. I'll post on the Dynon support forum just to
check, tho. Thanks.
Looking fwd to Oshkosh - hoping to be flying there next year.
Geoff
On Sat, May 28, 2011 at 10:13 AM, Scott Derrick <
<mailto:scott at tnstaafl.net> scott at tnstaafl.net> wrote:
My Century AP asks me to adjust trim when the flight conditions change.
There is no way the AP is going to overpower the trim spring and flight
loads.
Your training the AP as to how far it "can" move. Not testing its muscle.
I think its functioning normally but a call to Dynon may be in order.
Scott
-------- Original Message --------
Subject: REFLECTOR: Autopilot servos
From: Geoff Gerhardt <mailto:geoff at thegerhardts.com>
<geoff at thegerhardts.com>
To: Velocity Aircraft Owners and Builders list <mailto:reflector at tvbf.org>
<reflector at tvbf.org>
Date: 05/28/2011 05:31 AM
Hi all,
I installed my pitch autopilot servo and powered up my Dynon Skyview to get
it calibrated. The calibration process has you move the pitch to its
extremes to set the endpoints. Once calibrated, it tests the servo. I have
the Strong Pitch trim installed, so it takes quite a lot of force to
overcome the pitch trim (not sure if this is similar to the factory trim
system). Only with my help on the stick can the autopilot servo go to the
extremes - is that normal? Is it expected that the pilot will keep
adjusting the pitch while on AP so the servo doesn't have to work too hard?
Or, should I put a longer lever arm on the servo to increase the torque it
can deliver?
Thanks.
Geoff
_______________________________________________
To change your email address, visit
<http://www.tvbf.org/mailman/listinfo/reflector>
http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! <http://www.tvbf.org/gallery> www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: <http://www.tvbf.org/pipermail> www.tvbf.org/pipermail
Check old archives: <http://www.tvbf.org/archives/velocity/maillist.html>
http://www.tvbf.org/archives/velocity/maillist.html
--
One of the sanest, surest, and most generous joys of life comes from being
happy over the good fortune of others.
Robert A. Heinlein
_______________________________________________
To change your email address, visit
<http://www.tvbf.org/mailman/listinfo/reflector>
http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! <http://www.tvbf.org/gallery> www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: <http://www.tvbf.org/pipermail> www.tvbf.org/pipermail
Check old archives: <http://www.tvbf.org/archives/velocity/maillist.html>
http://www.tvbf.org/archives/velocity/maillist.html
_______________________________________________
To change your email address, visit
<http://www.tvbf.org/mailman/listinfo/reflector>
http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! <http://www.tvbf.org/gallery> www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: <http://www.tvbf.org/pipermail> www.tvbf.org/pipermail
Check old archives: <http://www.tvbf.org/archives/velocity/maillist.html>
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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20110529/d36b9f56/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 65140 bytes
Desc: not available
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20110529/d36b9f56/attachment-0002.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 48361 bytes
Desc: not available
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20110529/d36b9f56/attachment-0003.jpeg>
More information about the Reflector
mailing list