Today's Message Index:
----------------------
1. 04:59 AM - Re: Re: vibration in mains on roll out (Kelly McMullen)
2. 05:29 AM - Re: vibration in mains on roll out (rv10flyer)
3. 07:14 AM - Re: Re: vibration in mains on roll out (Pascal)
4. 07:53 AM - OT & Cross Post - reflections on the transition from analog to digital navigation equipment and failure modes (Bill Mauledriver Watson)
5. 10:22 AM - Re: Doing the windscreen - any last minutes tips? (Jim Berry)
6. 11:11 AM - PEM nuts (Jim Berry)
7. 11:23 AM - Re: Re: vibration in mains on roll out (RV Builder (Michael Sausen))
8. 12:01 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
9. 12:21 PM - Re: Re: vibration in mains on roll out (Don McDonald)
10. 01:10 PM - Re: Re: vibration in mains on roll out (Linn Walters)
11. 01:43 PM - Re: vibration in mains on roll out (rv10flyer)
12. 02:15 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
13. 02:15 PM - Re: Re: vibration in mains on roll out (RV Builder (Michael Sausen))
14. 03:45 PM - Re: Re: vibration in mains on roll out (Pascal)
15. 04:10 PM - Re: Re: vibration in mains on roll out (Tim Olson)
16. 04:44 PM - Re: vibration in mains on roll out (Tom Koelzer)
17. 04:52 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
18. 05:19 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
19. 05:47 PM - Re: Re: vibration in mains on roll out (Tom Koelzer)
20. 06:23 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
21. 07:40 PM - Re: Re: vibration in mains on roll out (Tom Koelzer)
22. 08:06 PM - Re: Re: vibration in mains on roll out (Bob Kaufmann)
23. 08:09 PM - Re: Re: vibration in mains on roll out (Tim Olson)
24. 08:28 PM - Reinforcing screw holes on wheel pants (Les Kearney)
25. 08:31 PM - Re: Re: vibration in mains on roll out (Kelly McMullen)
26. 08:45 PM - Re: Reinforcing screw holes on wheel pants (Pascal)
27. 08:46 PM - Re: Re: vibration in mains on roll out (ricksked@cox.net)
28. 08:51 PM - Re: Re: vibration in mains on roll out (Tom Koelzer)
29. 08:51 PM - Re: Reinforcing screw holes on wheel pants (ricksked@cox.net)
30. 09:02 PM - Re: Re: vibration in mains on roll out (Seano)
Message 1
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| Subject: | Re: vibration in mains on roll out |
I wish I understood why using the heaviest tire out there reduces the
vibration problem. Not to argue with results, just don't grasp the
physics.
On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
<building_partner@yahoo.com> wrote:
>
> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make sure
you get 15X6.00X6. It is so nice to not have the vibration
>
> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>
> From: greghale <ghale5224@aol.com>
> Subject: RV10-List: Re: vibration in mains on roll out
> To: rv10-list@matronics.com
> Date: Thursday, February 25, 2010, 4:05 PM
>
>
> DON,
>
> I have not been able to find the Goodyear FC3 tires. Where did you purchase them?
Also is the MICHELIN AIRSTOP TUBE what you used available from Aircraft Spruce?
>
> Greg...
>
> --------
> Greg Hale rv10 -- N210KH
> www.nwacaptain.com
Message 2
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| Subject: | Re: vibration in mains on roll out |
It may change the natural resonant frequency of the gear leg. Does it help or change
the speed at which the vibration occurs when your landing at or near gross
wt? If so, maybe for the same reason. I am going to make a note in the plans
about the braided lines/fcIII tires. Thanks guys.
--------
Wayne Gillispie
A&P 5/93, PPC 10/08
Grayson, KY
40983
Ord complete kit 8/24/09
DB Schenker del 11/20/09
Started emp 12/01/09
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=288278#288278
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| Subject: | Re: vibration in mains on roll out |
maybe its the roundness of the tire combined with balancing? tires are built
differently, I know from my motorcycle that there is a big difference from
the OEM stock tires I had and the touring tires I bought, the feel and
smoothness was noticeable, maybe same situation with the Goodyears.
just a thought
--------------------------------------------------
From: "Kelly McMullen" <apilot2@gmail.com>
Sent: Friday, February 26, 2010 4:56 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
>
> I wish I understood why using the heaviest tire out there reduces the
> vibration problem. Not to argue with results, just don't grasp the
> physics.
>
> On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
> <building_partner@yahoo.com> wrote:
>>
>> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make
>> sure you get 15X6.00X6. It is so nice to not have the vibration
>>
>> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>>
>> From: greghale <ghale5224@aol.com>
>> Subject: RV10-List: Re: vibration in mains on roll out
>> To: rv10-list@matronics.com
>> Date: Thursday, February 25, 2010, 4:05 PM
>>
>>
>> DON,
>>
>> I have not been able to find the Goodyear FC3 tires. Where did you
>> purchase them? Also is the MICHELIN AIRSTOP TUBE what you used
>> available from Aircraft Spruce?
>>
>> Greg...
>>
>> --------
>> Greg Hale rv10 -- N210KH
>> www.nwacaptain.com
>
>
>
Message 4
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| Subject: | OT & Cross Post - reflections on the transition from analog |
to digital navigation equipment and failure modes
Way off topic: Here's a video of an almost-accident by NZ60 landing at
Apia (Samoa?). It depicts how the failure of an ILS component at the
airport went undetected by multiple RF-based analog pieces of Nav
equipment including the ILS receivers, the FMS (digital?), and the
autopilot systems Only after the 3 pilots broke out and couldn't make
sense of the lights did their doubts finally result in a go-around
followed by a safe landing. Fascinating and informative for any
instrument pilot:
http://www.youtube.com/watch?v=GelRBhJ4gmI&feature=PlayList&p=C325C5DA287EC296&index=7
It's 3 parts long - if you enjoy it, you'll find part 2 and 3.
Anyway, this had me reflecting on how much more capable and reliable
digital based navigation (GPS) might be compared to analog based
systems. In the above example, everything in the aircraft worked as
designed. Procedures were for the most part, followed and executed.
The automated navigation systems of the aircraft were prepared to fly it
into the ground. The collective brain of the 3 pilots (NZ designation)
was the only thing that saved a crash. Is a WAAS based overlay of the
approach susceptible to a similiar sort of failure?
Arguably, one can now see the point in time where fully automated
flights, without pilots, can be accomplished. And of course these
flights are being made by mililtary drones and the Mars explorers.
No new news here, just marveling at it all.
I posted the response below to Sonex293 on the Aeroelectric list - check
the mikrokopter link at the bottom if you haven't seen it before.
That's what got me day dreaming in the first place....
--------
The next gen of OBAM aircraft? It reminds me that we are probably in
the golden age of OBAMA and personal GA (no pun intended).
Just reverse this scenario
http://alturl.com/gmqu
As unmanned and unpiloted aircraft hit their stride, those unpredictable
piloted aircraft with their free thinking, and at times, malevolent
pilots are going to be increasingly pushed into airspace restricted to
non-commercial, non-military, no-ATC-services areas. Probably to be
called 'uncontrolled' airspace... and we know how rare that has become.
Makes one savor the ability to hand fly our hand built aircraft from
coast to coast, all within the system.
Neat link. Thanks.
sonex293 wrote:
--> AeroElectric-List message posted by: "sonex293" <sonex293@gmail.com>
Kits are available...
http://www.mikrokopter.de/
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| Subject: | Re: Doing the windscreen - any last minutes tips? |
Bill,
The bottle jack and short 2x4 go under the spar stubs, and are used to tweak the
fuselage level side-to-side. The longer 2x4s are clamped to the aft sides of
the spar stubs to help maintain the level position. It needs to be long enough
to reach from the top of the spar to the floor. I used 2 C clamps per side.
I jacked the spars just enough to get the main tires about 1/4" off the ground,
then raised the low side a little more to bring the fuselage level. The C clamped
2x4s did a good job of maintaining that position, and showed no tendency
to walk. Once you have it leveled side-to-side it is easy to tweak the engine
hoist and/or tail support to get level fore and aft.
The other thing that really helped in getting the wheel pants in position was to
make 2 L-shaped jigs to hold the wheel pant level fore and aft. Basically just
2 plywood supports with one leg on the floor and the other leg perpendicular
to the floor. After you establish the fore and aft level line on each wheel
pant(use a laser level) you can measure the height from that line to the ground.
Drill a #40 hole in the nose and tail of each pant on the level line. Drill
a hole in each jig the same distance from the floor, and pin each jig to the
pant with a finishing nail. You now have a way to hold the pant level and at the
correct height. By moving the jigs around you have a stable way to position
the pant relative to the tire and mounting bracket. Have fun.
Jim Berry
40482
N15JB
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=288333#288333
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Don McDonald turned me on to PEM nuts recently, and I thought I would pass it on.
These are a fixed nut that can be used in many places instead of an AN365 nut
or anchor nut. They are quicker and easier to install than an anchor nut, and
they work well in places where there is not room for the legs of an anchor
nut. I used some on the elevator trim tab cable attach brackets., because it was
a pita to attach the access covers to the bracket with AN365 nuts and there
was not enough room to attach anchor nuts to the brackets. Just drill the appropriate
size hole and squeeze the nut into the hole with your rivet squeezer.
Available in many sizes, materials, locking & nonlocking.
Don's brother has some available at www.missileworks.com or see www.pemnet.com for a broader selection. They recommend the SL series for a locking nut in aluminum.
Jim Berry
40482
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=288341#288341
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| Subject: | Re: vibration in mains on roll out |
More mass and different materials to absorb the vibrations and convert it to something
else like heat. Same principals used in deadening sound.
Michael
-----Original Message-----
From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
Sent: Friday, February 26, 2010 6:57 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
I wish I understood why using the heaviest tire out there reduces the
vibration problem. Not to argue with results, just don't grasp the
physics.
On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
<building_partner@yahoo.com> wrote:
>
> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make sure
you get 15X6.00X6. It is so nice to not have the vibration
>
> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>
> From: greghale <ghale5224@aol.com>
> Subject: RV10-List: Re: vibration in mains on roll out
> To: rv10-list@matronics.com
> Date: Thursday, February 25, 2010, 4:05 PM
>
>
> DON,
>
> I have not been able to find the Goodyear FC3 tires. Where did you purchase them?
Also is the MICHELIN AIRSTOP TUBE what you used available from Aircraft Spruce?
>
> Greg...
>
> --------
> Greg Hale rv10 -- N210KH
> www.nwacaptain.com
Message 8
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| Subject: | Re: vibration in mains on roll out |
Is that some sort of an attempt to quantify your understanding of the problem?
..Mine came on progressively so I am leaning towards the tire as the main cause,
Don is here now and he swears that was the fix for him..if it were a gear specific
issue I would think it would have been there from the beginning right?
Sent via BlackBerry by AT&T
-----Original Message-----
From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
Subject: RE: RV10-List: Re: vibration in mains on roll out
More mass and different materials to absorb the vibrations and convert it to something
else like heat. Same principals used in deadening sound.
Michael
-----Original Message-----
From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
Sent: Friday, February 26, 2010 6:57 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
I wish I understood why using the heaviest tire out there reduces the
vibration problem. Not to argue with results, just don't grasp the
physics.
On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
<building_partner@yahoo.com> wrote:
>
> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make sure
you get 15X6.00X6. It is so nice to not have the vibration
>
> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>
> From: greghale <ghale5224@aol.com>
> Subject: RV10-List: Re: vibration in mains on roll out
> To: rv10-list@matronics.com
> Date: Thursday, February 25, 2010, 4:05 PM
>
>
> DON,
>
> I have not been able to find the Goodyear FC3 tires. Where did you purchase them?
Also is the MICHELIN AIRSTOP TUBE what you used available from Aircraft Spruce?
>
> Greg...
>
> --------
> Greg Hale rv10 -- N210KH
> www.nwacaptain.com
Message 9
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| Subject: | Re: vibration in mains on roll out |
Rick is at least partially correct... what I think may have happenned was t
hrough lots of, ok and not so ok landings, the balance in the tires simply
got worse and worse.- That imbalance feeds back through the gear legs, th
en at some point, they are unable to remain stable, and begin to shimmy.-
What I do know, is that it sure feels wonderful to be shimmy free.... and
I promise to make all my landings in the future, perfect!--- (--;
Don McDonald
--- On Fri, 2/26/10, ricksked@cox.net <ricksked@cox.net> wrote:
From: ricksked@cox.net <ricksked@cox.net>
Subject: Re: RV10-List: Re: vibration in mains on roll out
Is that some sort of an attempt to quantify your understanding of the probl
em? ..Mine came on progressively so I am leaning towards the tire as the ma
in cause, Don is here now and he swears that was the fix for him..if it wer
e a gear specific issue I would think it would have been there from the beg
inning right?
Sent via BlackBerry by AT&T
-----Original Message-----
From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
Subject: RE: RV10-List: Re: vibration in mains on roll out
ausen.net>
More mass and different materials to absorb the vibrations and convert it t
o something else like heat.- Same principals used in deadening sound.
Michael
-----Original Message-----
From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@m
atronics.com] On Behalf Of Kelly McMullen
Sent: Friday, February 26, 2010 6:57 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
I wish I understood why using the heaviest tire out there reduces the
vibration problem. Not to argue with results, just don't grasp the
physics.
On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
<building_partner@yahoo.com> wrote:
>
> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make
sure you get 15X6.00X6.-- It is so nice to not have the vibration
>
> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>
> From: greghale <ghale5224@aol.com>
> Subject: RV10-List: Re: vibration in mains on roll out
> To: rv10-list@matronics.com
> Date: Thursday, February 25, 2010, 4:05 PM
>
>
> DON,
>
> I have not been able to find the Goodyear FC3 tires.- Where did you pur
chase them?- Also is the- MICHELIN AIRSTOP TUBE what you used available
from Aircraft Spruce?
>
> Greg...
>
> --------
> Greg Hale rv10 -- N210KH
> www.nwacaptain.com
le, List Admin.
=0A=0A=0A
Message 10
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| Subject: | Re: vibration in mains on roll out |
I'd like to see some 'standard' for describing the antics of the landing
gear.
I refer to shimmy as the action of the nosewheel and tailwheels when
they act like a crippled shopping cart. That being a side-to side
castering. Cure is to tighten the spindle nut on the nosegear or
changing the angle of the tailwheel spindle.
As for the mains ... 'walking' would be the fore/aft movement as the
airplane rolls .... caused by many things. Caster (the way the wheel
center line points), brake rotor wobble (changing drag on the rotor) and
loose wheel bearings will cause this. There may be others that I
haven't come across.
The other antic is hop. Out of balance or out of round is the typical
cause.
Since we perceive all of the antics as an airframe vibration, the only
way to really tell is to get a pair of eyeballs to watch as you land to
see what's really going on.
I've heard of (but never seen) putting a hardwood fairing behind the
main gear to stiffen it to remove the 'walking'.
I'd also really like to see more discussion on gear issues from those
that have been there.
Linn
Don McDonald wrote:
> Rick is at least partially correct... what I think may have happenned
> was through lots of, ok and not so ok landings, the balance in the tires
> simply got worse and worse. That imbalance feeds back through the gear
> legs, then at some point, they are unable to remain stable, and begin to
> shimmy. What I do know, is that it sure feels wonderful to be shimmy
> free.... and I promise to make all my landings in the future,
> perfect! (--;
> Don McDonald
>
Message 11
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| Subject: | Re: vibration in mains on roll out |
Linn, I have seen that done on a Harmon Rocket. That is what made me think of the
carbon fiber as long as it fits underneath the stock leg fairings. It is nice
to see everyones ideas/comments on here.
Don, I like the "rough landings, leading to out of round/balance condition, then
leading to the vibration". I just wish the tapered rod gear legs were not so
sensitive, because my 172 landings are not perfect(I wish I could say they were).
I actually had more fun, had a better view and landings seemed a little easier
with my friends RV-9A. Have not done one in the -10. Just the demo ride last year
at snf with Joe Blank.
--------
Wayne Gillispie
A&P 5/93, PPC 10/08
Grayson, KY
40983
Ord complete kit 8/24/09
DB Schenker del 11/20/09
Started emp 12/01/09
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=288375#288375
Message 12
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| Subject: | Re: vibration in mains on roll out |
One thing I want to point out is if I allow the aircraft to roll out until taxi
speed then apply the brakes there isn't any wheel hop/vibration/shimmy or cocoa
bop.. I HAVEN'T ruled out brake chatter/grab except it does not occur stopping
from slow speeds...Now my theory is that when applying the brakes "hard" to
make the requested turn off causes the gear legs to move aft increasing the
toe out and causing the wheel to seek "it's" true track. The energy stored in
the gear leg overcomes the tire and in effect the swinging steel ball pendulum
starts to occur. I'm not so sure you will realize enough stiffness with a composite
or wood backing. Redesigning the gear into a flat shape rather than the
cylindrical that currently is in use may be the answer. Anyone get similar results
off grass? Grass would allow the tire to slide rather than trying to get
back in line with the track of the aircraft. Just brainstorming...
------Original Message------
From: rv10flyer
Sender: owner-rv10-list-server@matronics.com
ReplyTo: rv10-list@matronics.com
Sent: Feb 26, 2010 1:40 PM
Subject: RV10-List: Re: vibration in mains on roll out
Linn, I have seen that done on a Harmon Rocket. That is what made me think of the
carbon fiber as long as it fits underneath the stock leg fairings. It is nice
to see everyones ideas/comments on here.
Don, I like the "rough landings, leading to out of round/balance condition, then
leading to the vibration". I just wish the tapered rod gear legs were not so
sensitive, because my 172 landings are not perfect(I wish I could say they were).
I actually had more fun, had a better view and landings seemed a little easier
with my friends RV-9A. Have not done one in the -10. Just the demo ride last year
at snf with Joe Blank.
--------
Wayne Gillispie
A&P 5/93, PPC 10/08
Grayson, KY
40983
Ord complete kit 8/24/09
DB Schenker del 11/20/09
Started emp 12/01/09
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=288375#288375
Sent via BlackBerry by AT&T
Message 13
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| Subject: | Re: vibration in mains on roll out |
Are you two standing there playing with your Blackberry's? :D No, I have no
understanding, as I haven't experienced it. Kelly mentioned the physics of why
something heavy would dampen it and that's what I addressed. I believe my
comment in that context was accurate. HA! :P
Michael - having crackberry envy
-----Original Message-----
From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of ricksked@cox.net
Sent: Friday, February 26, 2010 1:56 PM
Subject: Re: RV10-List: Re: vibration in mains on roll out
Is that some sort of an attempt to quantify your understanding of the problem?
..Mine came on progressively so I am leaning towards the tire as the main cause,
Don is here now and he swears that was the fix for him..if it were a gear specific
issue I would think it would have been there from the beginning right?
Sent via BlackBerry by AT&T
-----Original Message-----
From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
Subject: RE: RV10-List: Re: vibration in mains on roll out
More mass and different materials to absorb the vibrations and convert it to something
else like heat. Same principals used in deadening sound.
Michael
-----Original Message-----
From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
Sent: Friday, February 26, 2010 6:57 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
I wish I understood why using the heaviest tire out there reduces the
vibration problem. Not to argue with results, just don't grasp the
physics.
On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
<building_partner@yahoo.com> wrote:
>
> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make sure
you get 15X6.00X6. It is so nice to not have the vibration
>
> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>
> From: greghale <ghale5224@aol.com>
> Subject: RV10-List: Re: vibration in mains on roll out
> To: rv10-list@matronics.com
> Date: Thursday, February 25, 2010, 4:05 PM
>
>
> DON,
>
> I have not been able to find the Goodyear FC3 tires. Where did you purchase them?
Also is the MICHELIN AIRSTOP TUBE what you used available from Aircraft Spruce?
>
> Greg...
>
> --------
> Greg Hale rv10 -- N210KH
> www.nwacaptain.com
Message 14
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| Subject: | Re: vibration in mains on roll out |
I have to think if the step gets to the point that many want to have an
access panel to resolve it that the gear may be the same issue.
Specifically, the bolt tends to become looser each time someone kicks off
the step or the gear absorbs the perfect landings causing it to slowly get
more loose.
Don has a resolution to his by replacing the tires and balancing them, that
may be the solution but there may be others, I am watching this issue
closely as there are far more complains about the gear than there are about
the doors flying off, yet Vans has never heard of this issue before anyone
calls them on it. BTW- Scott at Vans support has been straight up with me,
he's told me he knows of issues, has always given a suggestion and never
told me I was the first to tell him about it, never seems to even cross his
mind.. I would encourage some to give Vans a call and see if they have any
suggestions, maybe enough calls and they may pursue a solution.
--------------------------------------------------
From: <ricksked@cox.net>
Sent: Friday, February 26, 2010 11:55 AM
Subject: Re: RV10-List: Re: vibration in mains on roll out
>
> Is that some sort of an attempt to quantify your understanding of the
> problem? ..Mine came on progressively so I am leaning towards the tire as
> the main cause, Don is here now and he swears that was the fix for him..if
> it were a gear specific issue I would think it would have been there from
> the beginning right?
> Sent via BlackBerry by AT&T
>
> -----Original Message-----
> From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
> Date: Fri, 26 Feb 2010 13:21:57
> To: rv10-list@matronics.com<rv10-list@matronics.com>
> Subject: RE: RV10-List: Re: vibration in mains on roll out
>
> <rvbuilder@sausen.net>
>
> More mass and different materials to absorb the vibrations and convert it
> to something else like heat. Same principals used in deadening sound.
>
> Michael
>
> -----Original Message-----
> From: owner-rv10-list-server@matronics.com
> [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
> Sent: Friday, February 26, 2010 6:57 AM
> To: rv10-list@matronics.com
> Subject: Re: RV10-List: Re: vibration in mains on roll out
>
>
> I wish I understood why using the heaviest tire out there reduces the
> vibration problem. Not to argue with results, just don't grasp the
> physics.
>
> On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
> <building_partner@yahoo.com> wrote:
>>
>> Greg, sorry for the abbreviation.... Goodyear Flight Custom III's... make
>> sure you get 15X6.00X6. It is so nice to not have the vibration
>>
>> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>>
>> From: greghale <ghale5224@aol.com>
>> Subject: RV10-List: Re: vibration in mains on roll out
>> To: rv10-list@matronics.com
>> Date: Thursday, February 25, 2010, 4:05 PM
>>
>>
>> DON,
>>
>> I have not been able to find the Goodyear FC3 tires. Where did you
>> purchase them? Also is the MICHELIN AIRSTOP TUBE what you used
>> available from Aircraft Spruce?
>>
>> Greg...
>>
>> --------
>> Greg Hale rv10 -- N210KH
>> www.nwacaptain.com
>
>
>
Message 15
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|
| Subject: | Re: vibration in mains on roll out |
Nope....this one is just due to round gear legs. No big deal. Far
more an annoyance (minor) than a big deal. Start by balancing
everything and most people will be pretty ok. Some may have
variations of issues that make it less ok. But it's not an
overwhelming problem.
Tim
On Feb 26, 2010, at 5:34 PM, "Pascal" <rv10builder@verizon.net> wrote:
>
> I have to think if the step gets to the point that many want to have
> an access panel to resolve it that the gear may be the same issue.
> Specifically, the bolt tends to become looser each time someone
> kicks off the step or the gear absorbs the perfect landings causing
> it to slowly get more loose.
> Don has a resolution to his by replacing the tires and balancing
> them, that may be the solution but there may be others, I am
> watching this issue closely as there are far more complains about
> the gear than there are about the doors flying off, yet Vans has
> never heard of this issue before anyone calls them on it. BTW- Scott
> at Vans support has been straight up with me, he's told me he knows
> of issues, has always given a suggestion and never told me I was the
> first to tell him about it, never seems to even cross his mind.. I
> would encourage some to give Vans a call and see if they have any
> suggestions, maybe enough calls and they may pursue a solution.
>
> --------------------------------------------------
> From: <ricksked@cox.net>
> Sent: Friday, February 26, 2010 11:55 AM
> To: <rv10-list@matronics.com>
> Subject: Re: RV10-List: Re: vibration in mains on roll out
>
>>
>> Is that some sort of an attempt to quantify your understanding of
>> the problem? ..Mine came on progressively so I am leaning towards
>> the tire as the main cause, Don is here now and he swears that was
>> the fix for him..if it were a gear specific issue I would think it
>> would have been there from the beginning right?
>> Sent via BlackBerry by AT&T
>>
>> -----Original Message-----
>> From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
>> Date: Fri, 26 Feb 2010 13:21:57
>> To: rv10-list@matronics.com<rv10-list@matronics.com>
>> Subject: RE: RV10-List: Re: vibration in mains on roll out
>>
>> >
>>
>> More mass and different materials to absorb the vibrations and
>> convert it to something else like heat. Same principals used in
>> deadening sound.
>>
>> Michael
>>
>> -----Original Message-----
>> From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-
>> server@matronics.com] On Behalf Of Kelly McMullen
>> Sent: Friday, February 26, 2010 6:57 AM
>> To: rv10-list@matronics.com
>> Subject: Re: RV10-List: Re: vibration in mains on roll out
>>
>>
>> I wish I understood why using the heaviest tire out there reduces the
>> vibration problem. Not to argue with results, just don't grasp the
>> physics.
>>
>> On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
>> <building_partner@yahoo.com> wrote:
>>>
>>> Greg, sorry for the abbreviation.... Goodyear Flight Custom
>>> III's... make sure you get 15X6.00X6. It is so nice to not have
>>> the vibration
>>>
>>> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>>>
>>> From: greghale <ghale5224@aol.com>
>>> Subject: RV10-List: Re: vibration in mains on roll out
>>> To: rv10-list@matronics.com
>>> Date: Thursday, February 25, 2010, 4:05 PM
>>>
>>>
>>> DON,
>>>
>>> I have not been able to find the Goodyear FC3 tires. Where did
>>> you purchase them? Also is the MICHELIN AIRSTOP TUBE what you
>>> used available from Aircraft Spruce?
>>>
>>> Greg...
>>>
>>> --------
>>> Greg Hale rv10 -- N210KH
>>> www.nwacaptain.com
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 16
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|
| Subject: | Re: vibration in mains on roll out |
An engineering look at the problem (I got this off the web). My comments
below the math:
http://en.wikipedia.org/wiki/Fundamental_frequency
Consider a beam, fixed at one end and having a mass attached to the
other, this would be a single degree of freedom (SDoF) oscillator. Once
set into motion it will oscillate at its natural frequency. For a single
degree of freedom oscillator, a system in which the motion can be
described by a single coordinate, the natural frequency depends on two
system properties; mass and stiffness. The radian frequency, =CF=89n,
can be found using the following equation:
Where:
k = stiffness of the beam
m = mass of weight
=CF=89n = radian frequency (radians per second)
The stiffness, k, of a body is a measure of the resistance offered by an
elastic body to deformation (bending, stretching or compression).
where
P is a steady force applied on the body
=CE=B4 is the displacement produced by the force (for instance, the
deflection of a beam, or the change in length of a stretched spring)
=46rom the radian frequency, the natural frequency, fn, can be found by
simply dividing =CF=89n by 2=CF. Without first finding the radian
frequency, the natural frequency can be found directly using:
Where:
fn = natural frequency in hertz (cycles/second)
k = stiffness of the beam (Newtons/Meter or N/m)
m = mass of weight (kg) while doing the modal analysis of structures
and mechnical equipments, the frequency of 1st mode is called
fundamental frequency.
=================
My thoughts: The landing gear may have a natural frequency around the 40
mph or so speed some have experienced. At that speed, without much
energy required to excite the harmonic or resonance response, it doesn't
take much to cause a noticeable vibration (out of alignment, out of
balance, surface condition, gear loading due to gross weight, etc). The
wheel rpm at the offending speed could give us a clue as to the natural
frequency. That is frequency = velocity/tire circumference. Then work
the rest of the formulas backwards to determine theoretical mass and
maybe even do some stiffness measurements on the gear leg. Might get
close, might not but the goal here is to get a look at what it would
take to move the natural frequency around until it is no longer excited
during the takeoff or landing phase while on the ground.
Adding more weight, like a heavier tire, could conceivably lower the
natural frequency to the point where the natural damping of the steel
gear leg is such that at a lower speed the rotating wheel can no longer
excite the harmonic mode. Same goes for stiffening the gear leg with
carbon or wood: it may raise the frequency and damping factor such that
the mode again cannot be excited at the new condition. Classic spring
mass damper solution of sorts.
Perfect alignment, perfect balance, perfectly smooth landings and
runways would probably not excite the harmonic on roll-out. But we all
know these conditions don't last very long. So the answer is probably
some combination of straight gear (aligned), better damping (carbon
stiffener or other mod on to the gear leg to either raise the natural
frequency, damping or both), and balanced wheels and tires.
Sorry for all the formulas but it helped me think it out out,
Tom
#40950 waiting for long build wings.
Crestview, FL
On Feb 26, 2010, at 5:34 PM, Pascal wrote:
>
> I have to think if the step gets to the point that many want to have
an access panel to resolve it that the gear may be the same issue.
Specifically, the bolt tends to become looser each time someone kicks
off the step or the gear absorbs the perfect landings causing it to
slowly get more loose.
> Don has a resolution to his by replacing the tires and balancing them,
that may be the solution but there may be others, I am watching this
issue closely as there are far more complains about the gear than there
are about the doors flying off, yet Vans has never heard of this issue
before anyone calls them on it. BTW- Scott at Vans support has been
straight up with me, he's told me he knows of issues, has always given a
suggestion and never told me I was the first to tell him about it, never
seems to even cross his mind.. I would encourage some to give Vans a
call and see if they have any suggestions, maybe enough calls and they
may pursue a solution.
>
> --------------------------------------------------
> From: <ricksked@cox.net>
> Sent: Friday, February 26, 2010 11:55 AM
> To: <rv10-list@matronics.com>
> Subject: Re: RV10-List: Re: vibration in mains on roll out
Message 17
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|
| Subject: | Re: vibration in mains on roll out |
I agree...not much going on to do damage up high around the gear mount but you
can't help but wonder, the vibration is wonderful from an adult toy stand point,
I want to relax and have a cigarette after each landing. :)...Tim do you
still have this issue and just living with it?
Sent via BlackBerry by AT&T
-----Original Message-----
From: Tim Olson <Tim@MyRV10.com>
Subject: Re: RV10-List: Re: vibration in mains on roll out
Nope....this one is just due to round gear legs. No big deal. Far
more an annoyance (minor) than a big deal. Start by balancing
everything and most people will be pretty ok. Some may have
variations of issues that make it less ok. But it's not an
overwhelming problem.
Tim
On Feb 26, 2010, at 5:34 PM, "Pascal" <rv10builder@verizon.net> wrote:
>
> I have to think if the step gets to the point that many want to have
> an access panel to resolve it that the gear may be the same issue.
> Specifically, the bolt tends to become looser each time someone
> kicks off the step or the gear absorbs the perfect landings causing
> it to slowly get more loose.
> Don has a resolution to his by replacing the tires and balancing
> them, that may be the solution but there may be others, I am
> watching this issue closely as there are far more complains about
> the gear than there are about the doors flying off, yet Vans has
> never heard of this issue before anyone calls them on it. BTW- Scott
> at Vans support has been straight up with me, he's told me he knows
> of issues, has always given a suggestion and never told me I was the
> first to tell him about it, never seems to even cross his mind.. I
> would encourage some to give Vans a call and see if they have any
> suggestions, maybe enough calls and they may pursue a solution.
>
> --------------------------------------------------
> From: <ricksked@cox.net>
> Sent: Friday, February 26, 2010 11:55 AM
> To: <rv10-list@matronics.com>
> Subject: Re: RV10-List: Re: vibration in mains on roll out
>
>>
>> Is that some sort of an attempt to quantify your understanding of
>> the problem? ..Mine came on progressively so I am leaning towards
>> the tire as the main cause, Don is here now and he swears that was
>> the fix for him..if it were a gear specific issue I would think it
>> would have been there from the beginning right?
>> Sent via BlackBerry by AT&T
>>
>> -----Original Message-----
>> From: "RV Builder (Michael Sausen)" <rvbuilder@sausen.net>
>> Date: Fri, 26 Feb 2010 13:21:57
>> To: rv10-list@matronics.com<rv10-list@matronics.com>
>> Subject: RE: RV10-List: Re: vibration in mains on roll out
>>
>> >
>>
>> More mass and different materials to absorb the vibrations and
>> convert it to something else like heat. Same principals used in
>> deadening sound.
>>
>> Michael
>>
>> -----Original Message-----
>> From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-
>> server@matronics.com] On Behalf Of Kelly McMullen
>> Sent: Friday, February 26, 2010 6:57 AM
>> To: rv10-list@matronics.com
>> Subject: Re: RV10-List: Re: vibration in mains on roll out
>>
>>
>> I wish I understood why using the heaviest tire out there reduces the
>> vibration problem. Not to argue with results, just don't grasp the
>> physics.
>>
>> On Thu, Feb 25, 2010 at 10:30 PM, Don McDonald
>> <building_partner@yahoo.com> wrote:
>>>
>>> Greg, sorry for the abbreviation.... Goodyear Flight Custom
>>> III's... make sure you get 15X6.00X6. It is so nice to not have
>>> the vibration
>>>
>>> --- On Thu, 2/25/10, greghale <ghale5224@aol.com> wrote:
>>>
>>> From: greghale <ghale5224@aol.com>
>>> Subject: RV10-List: Re: vibration in mains on roll out
>>> To: rv10-list@matronics.com
>>> Date: Thursday, February 25, 2010, 4:05 PM
>>>
>>>
>>> DON,
>>>
>>> I have not been able to find the Goodyear FC3 tires. Where did
>>> you purchase them? Also is the MICHELIN AIRSTOP TUBE what you
>>> used available from Aircraft Spruce?
>>>
>>> Greg...
>>>
>>> --------
>>> Greg Hale rv10 -- N210KH
>>> www.nwacaptain.com
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 18
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|
| Subject: | Re: vibration in mains on roll out |
Ok...you win obviously an engineer quantifying his findings....I remember all that
stuff " heh yeah right" just never figured I'd use it in real life...knew
I should have paid better attention!!! Good show old man.... But you're like
20 years old right? How bout substituting numerical values to gear leg, mass
and resonance and other stuff like that, not being anything other than becoming
hungry for more knowledge
Sent via BlackBerry by AT&T
-----Original Message-----
From: Tom Koelzer <40950@rv10.net>
Subject: RV10-List: Re: vibration in mains on roll out
Message 19
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|
| Subject: | Re: vibration in mains on roll out |
I only wish I was 20 yrs. Aero engr, class of 76, A&M. I'm only getting ready to
do wings but if I get to the gear later and we are still having issues with
vibration, I know I'll work the problem. Maybe there are others out there with
gear interested in doing some measurements. I know there are some young engr
bucks out there with brains that work better than mine to do the math. And probably
have access to some really cool simulation applications on which to do the
analysis.
Tom
#40950
Gig 'em.
On Feb 26, 2010, at 7:09 PM, ricksked@cox.net wrote:
>
> Ok...you win obviously an engineer quantifying his findings....I remember all
that stuff " heh yeah right" just never figured I'd use it in real life...knew
I should have paid better attention!!! Good show old man.... But you're like
20 years old right? How bout substituting numerical values to gear leg, mass
and resonance and other stuff like that, not being anything other than becoming
hungry for more knowledge
> Sent via BlackBerry by AT&T
>
> -----Original Message-----
> From: Tom Koelzer <40950@rv10.net>
> Date: Fri, 26 Feb 2010 18:42:14
> To: <rv10-list@matronics.com>
> Subject: RV10-List: Re: vibration in mains on roll out
>
>
>
>
>
>
>
Message 20
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|
| Subject: | Re: vibration in mains on roll out |
Tom,
I will measure you do the math...let me know what you need and maybe we can provide
a definitive answer to this problem...we don't need no stinkin computer models...they
get confused predicting weather!
------Original Message------
From: Tom Koelzer
Sender: owner-rv10-list-server@matronics.com
ReplyTo: rv10-list@matronics.com
Sent: Feb 26, 2010 5:44 PM
Subject: Re: RV10-List: Re: vibration in mains on roll out
I only wish I was 20 yrs. Aero engr, class of 76, A&M. I'm only getting ready to
do wings but if I get to the gear later and we are still having issues with
vibration, I know I'll work the problem. Maybe there are others out there with
gear interested in doing some measurements. I know there are some young engr
bucks out there with brains that work better than mine to do the math. And probably
have access to some really cool simulation applications on which to do the
analysis.
Tom
#40950
Gig 'em.
On Feb 26, 2010, at 7:09 PM, ricksked@cox.net wrote:
>
> Ok...you win obviously an engineer quantifying his findings....I remember all
that stuff " heh yeah right" just never figured I'd use it in real life...knew
I should have paid better attention!!! Good show old man.... But you're like
20 years old right? How bout substituting numerical values to gear leg, mass
and resonance and other stuff like that, not being anything other than becoming
hungry for more knowledge
> Sent via BlackBerry by AT&T
>
> -----Original Message-----
> From: Tom Koelzer <40950@rv10.net>
> Date: Fri, 26 Feb 2010 18:42:14
> To: <rv10-list@matronics.com>
> Subject: RV10-List: Re: vibration in mains on roll out
>
>
>
>
>
>
>
Sent via BlackBerry by AT&T
Message 21
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|
| Subject: | Re: vibration in mains on roll out |
Hmm ... I have some ideas, let me research them. I need to look for some low cost
instrumentation to gather data for frequency measurement and load vs. displacement.
Maybe there is some low cost stuff out there I'm not aware of others
can turn me on to. Then do some calculations to confirm the theory with the actual
and decide where to go next. Like I said, might be easy, might be hard. But
definitely a fun science experiment.
Tom
do not archive
On Feb 26, 2010, at 8:18 PM, ricksked@cox.net wrote:
>
> Tom,
>
> I will measure you do the math...let me know what you need and maybe we can provide
a definitive answer to this problem...we don't need no stinkin computer
models...they get confused predicting weather!
Message 22
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|
| Subject: | Re: vibration in mains on roll out |
My calculations show that a clear spruce stiffener .0375 by 1.75 by 29.75
inch will take all the vibration out.
Bob K
P.S. Shares being offered in the Golden Gate Bridge at only $1.75 per
share.
Do not archive
-----Original Message-----
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Tom Koelzer
Sent: Friday, February 26, 2010 7:36 PM
Subject: Re: RV10-List: Re: vibration in mains on roll out
Hmm ... I have some ideas, let me research them. I need to look for some low
cost instrumentation to gather data for frequency measurement and load vs.
displacement. Maybe there is some low cost stuff out there I'm not aware of
others can turn me on to. Then do some calculations to confirm the theory
with the actual and decide where to go next. Like I said, might be easy,
might be hard. But definitely a fun science experiment.
Tom
do not archive
On Feb 26, 2010, at 8:18 PM, ricksked@cox.net wrote:
>
> Tom,
>
> I will measure you do the math...let me know what you need and maybe we
can provide a definitive answer to this problem...we don't need no stinkin
computer models...they get confused predicting weather!
Message 23
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|
| Subject: | Re: vibration in mains on roll out |
That's exactly what it is...a resonance issue. That's why we
all see it at the same speed to whatever degree it happens.
On mine, I can get a walking of the gear at high speed
taxi. Some days it's not there, but if you set off the
right vibration it'll trigger. Then you tap the brakes and
it's gone. On landing, after balancing my tires, it's usually
pretty good or nonexistant. But, before I balanced the tires,
or after they start to wear from things like flat spots (caused
by harsh braking or patchy ice) it can get easier to set off.
If you get anything that causes any up-down or fore-aft
motion, it'll trigger the resonance and it happens only for
maybe 5kts worth of speed range. Some days it doesn't happen
at all. Others, it'll give a good shake. But, it all does
get better with everything balanced. With tapered rod
gear like that, it's definitely going to happen to some people.
The stiffening of the gear may improve it with carbon fiber,
wood, or whatever, but, it may also just change it so that it
happens at some other resonant frequency or speed. With
things balanced I haven't found it to be any sort of major
problem. If maybe you have oddly toe'd or formed gear legs,
or tires, it may be different for you. Scott had bigger
problems with his Goodyear tires than his retreads....but
then again, each tire has a different shape/weight. I just
figure that with the gear legs our babies were born with, it's
going to be a fact of life to some degree. We could try
all sorts of things, and maybe be successful. But, for mine,
with things balanced, it's just not worth doing much to.
Before I balanced the tires, it bugged me a bit sometimes
though. I do think that axle nut tension is a factor too.
Try a little tighter or looser and it may change a bit.
Remember, there are a couple hundred RV-10's flying. Probably
a majority have at least felt a little of what this issue
is, but there are only a small handful of people who really
feel it's a big problem for them. Our planes aren't all
identical, so it's up to the builders to deal with their own
specific issues, and if they share their experiences then maybe
others with the issues can improve theirs too. But, there
are also a large share of RV-10's for which this isn't a big
issue at all. Considering there isn't much that can be done
BEFORE you find if you have a problem, other than a change in
gear leg design, just build the plane, fly it, balance
everything as best you can, and if you decide you need more,
share your ideas and see if it helps. But it's nothing to
worry about if you aren't already flying.
Tim Olson - RV-10 N104CD
Tom Koelzer wrote:
> An engineering look at the problem (I got this off the web). My comments below
the math:
>
> http://en.wikipedia.org/wiki/Fundamental_frequency
>
> Consider a beam, fixed at one end and having a mass attached to the other, this
would be a single degree of freedom (SDoF) oscillator. Once set into motion
it will oscillate at its natural frequency. For a single degree of freedom oscillator,
a system in which the motion can be described by a single coordinate,
the natural frequency depends on two system properties; mass and stiffness.
The radian frequency, ?n, can be found using the following equation:
>
>
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
>
> Where:
> k = stiffness of the beam
> m = mass of weight
> ?n = radian frequency (radians per second)
>
> The stiffness, k, of a body is a measure of the resistance offered by an elastic
body to deformation (bending, stretching or compression).
>
>
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
>
> where
> P is a steady force applied on the body
> ? is the displacement produced by the force (for instance, the deflection of
a beam, or the change in length of a stretched spring)
>
> From the radian frequency, the natural frequency, fn, can be found by simply
dividing ?n by 2?. Without first finding the radian frequency, the natural frequency
can be found directly using:
>
>
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
>
> Where:
> fn = natural frequency in hertz (cycles/second)
> k = stiffness of the beam (Newtons/Meter or N/m)
> m = mass of weight (kg) while doing the modal analysis of structures and mechnical
equipments, the frequency of 1st mode is called fundamental frequency.
>
> =================
>
> My thoughts: The landing gear may have a natural frequency around the 40 mph
or so speed some have experienced. At that speed, without much energy required
to excite the harmonic or resonance response, it doesn't take much to cause
a noticeable vibration (out of alignment, out of balance, surface condition, gear
loading due to gross weight, etc). The wheel rpm at the offending speed could
give us a clue as to the natural frequency. That is frequency = velocity/tire
circumference. Then work the rest of the formulas backwards to determine theoretical
mass and maybe even do some stiffness measurements on the gear leg.
Might get close, might not but the goal here is to get a look at what it would
take to move the natural frequency around until it is no longer excited during
the takeoff or landing phase while on the ground.
>
> Adding more weight, like a heavier tire, could conceivably lower the natural
frequency to the point where the natural damping of the steel gear leg is such
that at a lower speed the rotating wheel can no longer excite the harmonic mode.
Same goes for stiffening the gear leg with carbon or wood: it may raise the
frequency and damping factor such that the mode again cannot be excited at the
new condition. Classic spring mass damper solution of sorts.
>
> Perfect alignment, perfect balance, perfectly smooth landings and runways would
probably not excite the harmonic on roll-out. But we all know these conditions
don't last very long. So the answer is probably some combination of straight
gear (aligned), better damping (carbon stiffener or other mod on to the gear
leg to either raise the natural frequency, damping or both), and balanced
wheels and tires.
>
> Sorry for all the formulas but it helped me think it out out,
>
> Tom
>
> #40950 waiting for long build wings.
> Crestview, FL
>
>
>
> On Feb 26, 2010, at 5:34 PM, Pascal wrote:
>
>>
>> I have to think if the step gets to the point that many want to have an access
panel to resolve it that the gear may be the same issue. Specifically, the
bolt tends to become looser each time someone kicks off the step or the gear absorbs
the perfect landings causing it to slowly get more loose.
>> Don has a resolution to his by replacing the tires and balancing them, that
may be the solution but there may be others, I am watching this issue closely
as there are far more complains about the gear than there are about the doors
flying off, yet Vans has never heard of this issue before anyone calls them on
it. BTW- Scott at Vans support has been straight up with me, he's told me he
knows of issues, has always given a suggestion and never told me I was the first
to tell him about it, never seems to even cross his mind.. I would encourage
some to give Vans a call and see if they have any suggestions, maybe enough
calls and they may pursue a solution.
>>
>> --------------------------------------------------
>> From: <ricksked@cox.net>
>> Sent: Friday, February 26, 2010 11:55 AM
>> To: <rv10-list@matronics.com>
>> Subject: Re: RV10-List: Re: vibration in mains on roll out
>
Message 24
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| Subject: | Reinforcing screw holes on wheel pants |
Okay,
After being severely repremanded about glassing in the nose wheel mounting
bracket, I have finished mounting my pants per the plans. Now I am concerned
that the screw holes are somewhat enlarged due to countersinking and will
fail over time. Is there a preferred way to reinforce screw holes in
fiberglass.
Inquiring mindfs need to know.
Les
#40643
Message 25
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| Subject: | Re: vibration in mains on roll out |
I can give you a better deal on ocean beach front property in Aridzona. ;-)
1K per acre.
On Fri, Feb 26, 2010 at 9:05 PM, Bob Kaufmann <bob.kaufmann@cox.net> wrote:
> P.S. Shares being offered in the Golden Gate Bridge at only $1.75 per
> share.
> Do not archive
>
Message 26
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| Subject: | Re: Reinforcing screw holes on wheel pants |
If I recall correctly you should have some flox between the screw holes
and bracket.. so there should be plenty of strength, you can use a
countersunk washer, forget the screw size, but they sell them for all
sizes. Good thing about fiberglass is you can just flow the hole in the
inside again throw a few layers of glass on top and start over in a year
or two if there is a problem.
From: Les Kearney
Sent: Friday, February 26, 2010 8:26 PM
Subject: RV10-List: Reinforcing screw holes on wheel pants
Okay,
After being severely repremanded about glassing in the nose wheel
mounting bracket, I have finished mounting my pants per the plans. Now I
am concerned that the screw holes are somewhat enlarged due to
countersinking and will fail over time. Is there a preferred way to
reinforce screw holes in fiberglass.
Inquiring mindfs need to know.
Les
#40643
Message 27
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| Subject: | Re: vibration in mains on roll out |
Whatever The F that means
Sent via BlackBerry by AT&T
-----Original Message-----
From: "Bob Kaufmann" <bob.kaufmann@cox.net>
Subject: RE: RV10-List: Re: vibration in mains on roll out
My calculations show that a clear spruce stiffener .0375 by 1.75 by 29.75
inch will take all the vibration out.
Bob K
P.S. Shares being offered in the Golden Gate Bridge at only $1.75 per
share.
Do not archive
-----Original Message-----
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Tom Koelzer
Sent: Friday, February 26, 2010 7:36 PM
Subject: Re: RV10-List: Re: vibration in mains on roll out
Hmm ... I have some ideas, let me research them. I need to look for some low
cost instrumentation to gather data for frequency measurement and load vs.
displacement. Maybe there is some low cost stuff out there I'm not aware of
others can turn me on to. Then do some calculations to confirm the theory
with the actual and decide where to go next. Like I said, might be easy,
might be hard. But definitely a fun science experiment.
Tom
do not archive
On Feb 26, 2010, at 8:18 PM, ricksked@cox.net wrote:
>
> Tom,
>
> I will measure you do the math...let me know what you need and maybe we
can provide a definitive answer to this problem...we don't need no stinkin
computer models...they get confused predicting weather!
Message 28
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| Subject: | Re: vibration in mains on roll out |
These are great discussions. And thanks, Tim, you have a great insight for what
really matter. Flying is what matters, safe flying. This is an nuisance that
I find particularly interesting because of my background (aero engr and flight
test) and does not threaten safety of the vehicle. But a nuisance none the less.
So generally speaking, I think there may be a resonance mode with the gear that
causes problems for some and not for others. The catalyst is what excites the
mode and how to dampen it. If not excited, nothing happens (all guys know this).
I'm interested in a solution, long term. This is not like doors flying off
the airplane. This is like explaining to my mother why my airplane shakes when
I land when she rides with me. It's just that simple. No problem, maybe only
an embarrassment. I'd like to contribute to a solution for those who see this
problem more than others and are interested in doing something about it. Van's
might have an idea or two as well (other than wood glued to the landing gear).
I'll ask later if we get to that point.
I'll talk to Neal and see what we can come up with regard to cheap instrumentation.
I have other ideas to pursue. If there is little interest, that's ok. I believe
in supply and demand as the driver to all solutions. If I see this when
I finally get to the gear and flying, then I'll tackle the problem again.
Tom aka Cowboy
On Feb 26, 2010, at 10:07 PM, Tim Olson wrote:
>
> That's exactly what it is...a resonance issue. That's why we
> all see it at the same speed to whatever degree it happens.
> On mine, I can get a walking of the gear at high speed
> taxi. Some days it's not there, but if you set off the
> right vibration it'll trigger. Then you tap the brakes and
> it's gone. On landing, after balancing my tires, it's usually
> pretty good or nonexistant. But, before I balanced the tires,
> or after they start to wear from things like flat spots (caused
> by harsh braking or patchy ice) it can get easier to set off.
> If you get anything that causes any up-down or fore-aft
> motion, it'll trigger the resonance and it happens only for
> maybe 5kts worth of speed range. Some days it doesn't happen
> at all. Others, it'll give a good shake. But, it all does
> get better with everything balanced. With tapered rod
> gear like that, it's definitely going to happen to some people.
> The stiffening of the gear may improve it with carbon fiber,
> wood, or whatever, but, it may also just change it so that it
> happens at some other resonant frequency or speed. With
> things balanced I haven't found it to be any sort of major
> problem. If maybe you have oddly toe'd or formed gear legs,
> or tires, it may be different for you. Scott had bigger
> problems with his Goodyear tires than his retreads....but
> then again, each tire has a different shape/weight. I just
> figure that with the gear legs our babies were born with, it's
> going to be a fact of life to some degree. We could try
> all sorts of things, and maybe be successful. But, for mine,
> with things balanced, it's just not worth doing much to.
> Before I balanced the tires, it bugged me a bit sometimes
> though. I do think that axle nut tension is a factor too.
> Try a little tighter or looser and it may change a bit.
>
> Remember, there are a couple hundred RV-10's flying. Probably
> a majority have at least felt a little of what this issue
> is, but there are only a small handful of people who really
> feel it's a big problem for them. Our planes aren't all
> identical, so it's up to the builders to deal with their own
> specific issues, and if they share their experiences then maybe
> others with the issues can improve theirs too. But, there
> are also a large share of RV-10's for which this isn't a big
> issue at all. Considering there isn't much that can be done
> BEFORE you find if you have a problem, other than a change in
> gear leg design, just build the plane, fly it, balance
> everything as best you can, and if you decide you need more,
> share your ideas and see if it helps. But it's nothing to
> worry about if you aren't already flying.
>
> Tim Olson - RV-10 N104CD
>
Message 29
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| Subject: | Re: Reinforcing screw holes on wheel pants |
Les use stainless countersink washers on the glass, brush thinned epoxy on the
fiberglass before using the washers, this will reinforce the hole, the washer
will distribute the load.
Sent via BlackBerry by AT&T
-----Original Message-----
From: "Les Kearney" <kearney@shaw.ca>
Subject: RV10-List: Reinforcing screw holes on wheel pants
This is a multi-part message in MIME format.
Message 30
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| Subject: | Re: vibration in mains on roll out |
I am anxious to see how mine will do. Awhile back I redrilled my left gear
leg so both wheels were pointed in 1.10 degrees. I only used 1.10 because
the right gear was set there from construction when lining up the factory
holes. I moved the left gear to match since it was toed out and the right
was toed in. I called Van's to make sure the bolt I used would be
structurally ok. We'll see!
----- Original Message -----
From: "Tom Koelzer" <40950@rv10.net>
Sent: Friday, February 26, 2010 9:49 PM
Subject: Re: RV10-List: Re: vibration in mains on roll out
These are great discussions. And thanks, Tim, you have a great insight for
what really matter. Flying is what matters, safe flying. This is an nuisance
that I find particularly interesting because of my background (aero engr and
flight test) and does not threaten safety of the vehicle. But a nuisance
none the less.
So generally speaking, I think there may be a resonance mode with the gear
that causes problems for some and not for others. The catalyst is what
excites the mode and how to dampen it. If not excited, nothing happens (all
guys know this). I'm interested in a solution, long term. This is not like
doors flying off the airplane. This is like explaining to my mother why my
airplane shakes when I land when she rides with me. It's just that simple.
No problem, maybe only an embarrassment. I'd like to contribute to a
solution for those who see this problem more than others and are interested
in doing something about it. Van's might have an idea or two as well (other
than wood glued to the landing gear). I'll ask later if we get to that
point.
I'll talk to Neal and see what we can come up with regard to cheap
instrumentation. I have other ideas to pursue. If there is little interest,
that's ok. I believe in supply and demand as the driver to all solutions. If
I see this when I finally get to the gear and flying, then I'll tackle the
problem again.
Tom aka Cowboy
On Feb 26, 2010, at 10:07 PM, Tim Olson wrote:
>
> That's exactly what it is...a resonance issue. That's why we
> all see it at the same speed to whatever degree it happens.
> On mine, I can get a walking of the gear at high speed
> taxi. Some days it's not there, but if you set off the
> right vibration it'll trigger. Then you tap the brakes and
> it's gone. On landing, after balancing my tires, it's usually
> pretty good or nonexistant. But, before I balanced the tires,
> or after they start to wear from things like flat spots (caused
> by harsh braking or patchy ice) it can get easier to set off.
> If you get anything that causes any up-down or fore-aft
> motion, it'll trigger the resonance and it happens only for
> maybe 5kts worth of speed range. Some days it doesn't happen
> at all. Others, it'll give a good shake. But, it all does
> get better with everything balanced. With tapered rod
> gear like that, it's definitely going to happen to some people.
> The stiffening of the gear may improve it with carbon fiber,
> wood, or whatever, but, it may also just change it so that it
> happens at some other resonant frequency or speed. With
> things balanced I haven't found it to be any sort of major
> problem. If maybe you have oddly toe'd or formed gear legs,
> or tires, it may be different for you. Scott had bigger
> problems with his Goodyear tires than his retreads....but
> then again, each tire has a different shape/weight. I just
> figure that with the gear legs our babies were born with, it's
> going to be a fact of life to some degree. We could try
> all sorts of things, and maybe be successful. But, for mine,
> with things balanced, it's just not worth doing much to.
> Before I balanced the tires, it bugged me a bit sometimes
> though. I do think that axle nut tension is a factor too.
> Try a little tighter or looser and it may change a bit.
>
> Remember, there are a couple hundred RV-10's flying. Probably
> a majority have at least felt a little of what this issue
> is, but there are only a small handful of people who really
> feel it's a big problem for them. Our planes aren't all
> identical, so it's up to the builders to deal with their own
> specific issues, and if they share their experiences then maybe
> others with the issues can improve theirs too. But, there
> are also a large share of RV-10's for which this isn't a big
> issue at all. Considering there isn't much that can be done
> BEFORE you find if you have a problem, other than a change in
> gear leg design, just build the plane, fly it, balance
> everything as best you can, and if you decide you need more,
> share your ideas and see if it helps. But it's nothing to
> worry about if you aren't already flying.
>
> Tim Olson - RV-10 N104CD
>
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