Today's Message Index:
----------------------
1. 09:48 AM - Re: tail wag (Lee Taylor)
2. 11:51 PM - Re: tail wag (Fred Weaver)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> Rocket-List message posted by: "Lee Taylor " <leetay@comcast.net>
This is in reference to a problem discussed a couple of months back, where
some owners were experiencing a rudder oscillation/tail wag problem:
Re Rocket Tail Wag:
This is not directed specifically at the Rocket, but I had a similar
problem with my Midget Mustang, except it was on the ELEVATOR. It also had
a folded-skin trailing edge, and it would oscillate the same as described as
the rudder oscillation you guys are talking about with the Rocket. Elevator
oscillation is a "little more noticeable" than rudder oscillation, tho!
My problem was that the fold for the trailing edge wasn't completely
finished,--- the builder allowed the ribs to finish pulling the skin into
alignment, which left a small "bow" on the skins' railing edge, rather than
a straight line across the surface. This was seemingly inconsequential,
except what it did was make a small AIRFOIL on the trailing edge.
This airfoil was not totally symmetrical, so the effect was that at
normal displacements, this airfoil had a slight lifting effect,--i.e, an
"up-elevator" trim effect. Left alone, it would "lift" the trailing edge of
the elevator until that side of the airfoil lost lift, then the
opposite-side airfoil would take over and "de-lift" it back the other
direction.
The result, if not stick-force damped, was an elevator oscillation
that was downright impressive! I could develop +,- 3 G's real quick! This
stick-force damping is exactly the same as some of the guys describing
holding a firm rudder pressure to dampen your rudder oscillations.
The fix was simple. Finish the bend so that there was no skin bulge
at the trailing edge. I ran a 3/32" dowel down the inside of the bend, (to
assure maintaining a bend radius), then using two 2x4's for clamp jaws,
C-clamped the 2x4's down squeezing the trailing edge until the trailing edge
bend was completed, and there was no curvature remaining at the trailing
edge of the skins.
VIOLA! Oscillation gone, and a very nice, perfectly trimmed stable
airplane obtained.
I feel that the Rocket rudder oscillation is probably the same
effect, and reason. Also, the riveted trailing edges rudders DON'T have the
problem, for the same reason.
If you are experiencing this rudder oscillation with
folded-trailing-edge skins, check if you might have this slight bow in the
skins at your trailing edges. If you do, do the same as I did, and
eliminate it. I think your problem will go away.
Lee Taylor
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> Rocket-List message posted by: "Fred Weaver" <Mytyweav@earthlink.net>
Nope..... Not even close to the same symptoms.. But a nice try.
Weav
----- Original Message -----
From: "Lee Taylor " <leetay@comcast.net>
Subject: Re: Rocket-List: tail wag
> --> Rocket-List message posted by: "Lee Taylor " <leetay@comcast.net>
>
> This is in reference to a problem discussed a couple of months back, where
> some owners were experiencing a rudder oscillation/tail wag problem:
>
> Re Rocket Tail Wag:
>
> This is not directed specifically at the Rocket, but I had a
similar
> problem with my Midget Mustang, except it was on the ELEVATOR. It also
had
> a folded-skin trailing edge, and it would oscillate the same as described
as
> the rudder oscillation you guys are talking about with the Rocket.
Elevator
> oscillation is a "little more noticeable" than rudder oscillation, tho!
> My problem was that the fold for the trailing edge wasn't
completely
> finished,--- the builder allowed the ribs to finish pulling the skin into
> alignment, which left a small "bow" on the skins' railing edge, rather
than
> a straight line across the surface. This was seemingly inconsequential,
> except what it did was make a small AIRFOIL on the trailing edge.
> This airfoil was not totally symmetrical, so the effect was that
at
> normal displacements, this airfoil had a slight lifting effect,--i.e, an
> "up-elevator" trim effect. Left alone, it would "lift" the trailing edge
of
> the elevator until that side of the airfoil lost lift, then the
> opposite-side airfoil would take over and "de-lift" it back the other
> direction.
> The result, if not stick-force damped, was an elevator oscillation
> that was downright impressive! I could develop +,- 3 G's real quick! This
> stick-force damping is exactly the same as some of the guys describing
> holding a firm rudder pressure to dampen your rudder oscillations.
> The fix was simple. Finish the bend so that there was no skin
bulge
> at the trailing edge. I ran a 3/32" dowel down the inside of the bend,
(to
> assure maintaining a bend radius), then using two 2x4's for clamp jaws,
> C-clamped the 2x4's down squeezing the trailing edge until the trailing
edge
> bend was completed, and there was no curvature remaining at the trailing
> edge of the skins.
> VIOLA! Oscillation gone, and a very nice, perfectly trimmed
stable
> airplane obtained.
> I feel that the Rocket rudder oscillation is probably the same
> effect, and reason. Also, the riveted trailing edges rudders DON'T have
the
> problem, for the same reason.
> If you are experiencing this rudder oscillation with
> folded-trailing-edge skins, check if you might have this slight bow in the
> skins at your trailing edges. If you do, do the same as I did, and
> eliminate it. I think your problem will go away.
>
> Lee Taylor
>
>
> _-=====================================================================
> _-> _-= -- Please Support Your Lists This Month --
> _-= (And Get Some AWESOME FREE Gifts!)
> _-> _-= November is the Annual List Fund Raiser. Click on the
> _-= Contribution link below to find out more about this
> _-= year's Terrific Free Incentive Gifts provided by the
> _-= The Builder's Bookstore www.buildersbooks.com!
> _-> _-= List Contribution Web Site
> _-> _-= http://www.matronics.com/contribution
> _-> _-= Thank you for your generous support!
> _-= -Matt Dralle, List Admin.
> _-> _-=====================================================================
> _-= - The Rocket-List Email Forum -
> _-= This forum is sponsored entirely through the Contributions
> _-= of List members. You'll never see banner ads or any other
> _-= form of direct advertising on the Matronics Forums.
> _-=====================================================================
> _-= List Related Information
> _-= Post Message: rocket-list@matronics.com
> _-= UN/SUBSCRIBE: http://www.matronics.com/subscription
> _-= List FAQ: http://www.matronics.com/FAQ/Rocket-List.htm
> _-= Search Engine: http://www.matronics.com/search
> _-= 7-Day Browse: http://www.matronics.com/browse/rocket-list
> _-= Browse Digests: http://www.matronics.com/digest/rocket-list
> _-= Live List Chat: http://www.matronics.com/chat
> _-= Archives: http://www.matronics.com/archives
> _-= Photo Share: http://www.matronics.com/photoshare
> _-= List Specific: http://www.matronics.com/rocket-list
> _-= Other Lists: http://www.matronics.com/emaillists
> _-= Trouble Report http://www.matronics.com/trouble-report
> _-= Contributions: http://www.matronics.com/contribution
> _-=====================================================================
>
>
_-=====================================================================
_-_-= -- Please Support Your Lists This Month --
_-= (And Get Some AWESOME FREE Gifts!)
_-_-= November is the Annual List Fund Raiser. Click on the
_-= Contribution link below to find out more about this
_-= year's Terrific Free Incentive Gifts provided by the
_-= The Builder's Bookstore www.buildersbooks.com!
_-_-= List Contribution Web Site
_-_-= http://www.matronics.com/contribution
_-_-= Thank you for your generous support!
_-= -Matt Dralle, List Admin.
_-_-=====================================================================
_-= - The Rocket-List Email Forum -
_-= This forum is sponsored entirely through the Contributions
_-= of List members. You'll never see banner ads or any other
_-= form of direct advertising on the Matronics Forums.
_-=====================================================================
_-= List Related Information
_-= Post Message: rocket-list@matronics.com
_-= UN/SUBSCRIBE: http://www.matronics.com/subscription
_-= List FAQ: http://www.matronics.com/FAQ/Rocket-List.htm
_-= Search Engine: http://www.matronics.com/search
_-= 7-Day Browse: http://www.matronics.com/browse/rocket-list
_-= Browse Digests: http://www.matronics.com/digest/rocket-list
_-= Live List Chat: http://www.matronics.com/chat
_-= Archives: http://www.matronics.com/archives
_-= Photo Share: http://www.matronics.com/photoshare
_-= List Specific: http://www.matronics.com/rocket-list
_-= Other Lists: http://www.matronics.com/emaillists
_-= Trouble Report http://www.matronics.com/trouble-report
_-= Contributions: http://www.matronics.com/contribution
_-=====================================================================
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|