Today's Message Index:
----------------------
1. 12:10 AM - gear (Wheeler North)
2. 05:32 AM - Re: Toe (linn walters)
3. 06:10 AM - Re: toe (Cy Galley)
4. 07:21 AM - Seats (bert murillo)
5. 09:21 AM - Re: Seats (Tim Coldenhoff)
6. 08:16 PM - a test (jim jewell)
7. 09:08 PM - Build Wings Together or Separate? ()
8. 09:37 PM - Jiffy Trim (Rob W M Shipley)
9. 09:42 PM - What size is GPS coax? (Jerry Calvert)
10. 09:59 PM - Re: What size is GPS coax? (Larry Bowen)
11. 10:34 PM - Re: What size is GPS coax? (Jerry Calvert)
12. 11:12 PM - Re: What size is GPS coax? (Stein Bruch)
Message 1
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--> RV-List message posted by: Wheeler North <wnorth@sdccd.cc.ca.us>
What started the discussion was the fact that Vans did a really bad job of
factory drilling my gear mounts on a RV-6.
And yes the -As are different in that they are independant of each other. So
I wouldn't trust Vans ability to align this, I would check it yourself via
the board method, and then check it again as I described too many posts ago,
right before you fly it.
Or buy tires and live with it...
But if you want it right, its becoming clear that the design books are
written by someone who has never flown an airplane, but most of the
maintenance documentation for many aircraft will give you some good advice.
Have an engineer design it then hire a mechanic to make it useable.
W
Time: 04:25:15 PM PST US
From: Hopperdhh@aol.com
Subject: Re: RV-List: Web references on toe-in/toe-out
--> RV-List message posted by: Hopperdhh@aol.com
I'm there now and I guess I'm a little confused. How do I change toe?
Van's
drills one hole for you which essentially defines toe and camber. All you
can do is enlarge the other hole to match the gearleg and the first hole. I
think it would get pretty messy putting washers or shims between the gear
weldments and the spar. I'm building an RV-7A. Is the arrangement
different on
the
other Vans airplanes?
Dan N766DH almost finished
In a message dated 2/5/04 6:54:29 PM US Eastern Standard Time,
bgarrett920@comcast.net writes:
> Just my opinion, which may change before I'm flying but I think if I were
> there now I'd try to set toe to complement whatever camber exists to
balance
> each other as a starting point and then adjust once flying if the plane
> doesn't handle well on the ground. Of course with a trike I don't think
> it's a big a concern for me either.
>
>
Message 2
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--> RV-List message posted by: linn walters <lwalters2@cfl.rr.com>
Wheeler North wrote:
>--> RV-List message posted by: Wheeler North <wnorth@sdccd.cc.ca.us>
>
>
><Of course, all of this analysis depends on the static case, where you're
>making a smooth landing on a smooth paved strip.
>
Now, how often does that happen?
> If you're landing on a
>bumpy grass strip, and your gearleg is "bouncy", your wheel could be
>oscillating from toed-in to toed-out, and cambered-in to cambered-out,
>at the same time.
>
Kinda like a tapered steel gear leg???
> Still, you have to be able to analyze it, so you work
>with the assumed "mean" position of the wheel. Which will be the static
>case.
>
Now gear has personality! "yeah, my gear is only a little mean .....
not as mean as yours."
>The best part of a grass strip is tire slide, the tires slide a lot so
>effects of toe in or out are minimized.
>
Not really true! But then it could have been exhilarated pilots doing
donuts and showing off. well, everyone was watching!
>Yes and no, a ground loop is almost always caused by poor control
>techniques, or excessive landing conditions (cross wind). Alignment will add
>to this, but a good landing in stable conditions will overcome poor
>alignment if its not too whacked out.
>
Ah, so that's what that rudder does!!!
><
>I don't think so. As the heavy wheel runs away from it's CG vector, the
>heaviness decreases, and it reaches a static state. Of course there
>will be an oscillation around the static point, but it will approach
>that static point as the plane settles and both wheels get on the
>ground. During this time, the lateral force is oscillating between
>stabilizing (which is good) and no force at all (or maybe slight
>destabilizing, if the wheel oscillates to a toed-in alignment).
>
Huh?
>As the heavy wheel runs away it also drags the aircraft with it, turning it,
>or at least shifting its inertia to the opposite side. This causes the
>aircraft to then jump to the other wheel and it repeats in reverse. This is
>ususally a dynamically negatively stable oscillation, IE get worse each
>cycle.
>
If true, then taildraggers would slalom down the runway instead of doing
donuts.
>Picture the extreme, a penguin sliding on ice. As it leans to the left that
>flipper, which is toed out, begins to dig in and add drag and trys to move
>outwards, this spins the penguin to the left and now its inertia is pointing
>to the right side. Load then shifts from the left to the right and the right
>flipper digs in.
>
Oh God! Now we're all going to watch animal planet! Who, in his right
mind, has been studying the toe in/out of a penguins flipper???? C'mon now!
>But if your wheels are toed-in, the heavy wheel will be fighting your
>ability to land smoothly from the time it hits. The lateral force will
>be oscillating between destabilizing (which is bad) and no force at all
>(or maybe slight stabilizing, if the wheel oscillates to toed-out).
>
Here we go again. KISS. If the wheels are toed in, and the turn is
initiated (however it happens), then the CG transfers a little more to
the outside and the gear flexes more and the tire starts to wheelbarrow
and more weight is transferred to that side and you've just been dumped
in Mr. Toads Wild Ride.
><
>Yes, this is true for severe toe in (greater than 5 degs) but slight toe in
>(less than one deg) has very little effect on static stablility.
>
The only static stability we can talk about in this thread (and it's
been a long one!) is in the hangar with the doors closed. A landing is
about as dynamic as it gets.
> The
>controllability of the aircraft easily overcomes this, and there is no force
>trying to make the aircraft hop back and forth left to right, which is very
>difficult to control.
>
The controllability is why we're here. At the point where everything
goes to crap, you're in between controllabiility from rudder and
ailerons and controllability due to weight on the gear. I've never seen
an airplane of any configuration 'hop back and forth' so maybe I've been
missing something all these years.
>>Usually when a pilot squacks "squirrley" this is what I look for,
>>ie: large toe out as evidenced by sharp ridges on the outboard edges of
>>
>>
>the tire tread ribs.
>
I'm not a tire expert so I'll let this one pass. I've never seen this
phenomenon.
>Are you sure we're talking about the same thing? Toe-out or toe-in, the
>wheel could still be contacting the ground at the center of it's tread.
> Are you thinking camber, ie. the top of the tire further out than the
>bottom, and not toe-in/out, ie. the front of the tire further in/out
>than the rear?
>
In my discussions about my Pitts gear, it became apparent that camber
plays a huge part in the groundloop scenario once the activity is
esstablished.
><
>Yes I'm sure, Camber causes one side of the tire to wear, toe causes the
>tire to scrubb laterally across the ribs. The direction of lateral scrubb
>will always be from rounded tread groove corners to sharp feathered groove
>corners. If rounded is inboard its toed out, if rounded is outboard its toed
>in.
>
Your stuck thinking in a static gear situation, and that doesn't exist
in the ground-loop or handling problems scenario.
>You say it, but it's not clear that this happens. At least, it's not
>clear that it would happen on a toed-out gear, but wouldn't on a toed-in
>gear. If it's toed-out to start with and oscillates between in and out,
>then the same should be true if it was toed-in to start with. Toed in
>is less stable.
>
True, and if you visualize the toe-in/out radically, you might see the
picture. As long as equal weight is placed on ecah of the mains,
nothing happens ..... the gear finally gets to a stable position and the
tires scrub a little. Once things start to get out of hand (more weight
and gear flexing on one side) you find out how the gear is aligned.
>It will do this in reverse, but when toed in, the wheel that is shifting
>track won't be the heavy wheel.
>
Not true. This wheel gets increasing weight due to shifting CG.
>If you are leaning on the left wheel and the right wheel shifts track its
>not a big deal, but if the left one does it will be a bigger deal partly
>because of load shift, and partly because your outboard wheel track will
>have just moved to a tighter radius thereby increasing side loading at an
>unpredictible rate.
>
Ah, some glimmer of the problem.
>This may be a good thing to measure on an RV, as I can't see this no
>matter how hard I try to configure it in my head. When I simulate it
>using a wire, the static loading case (aircraft not moving) doesn't show
>any real change in toe-in or toe-out, but if anything it's a slight
>toe-out. When you add the landing load, which is a drag force applied
>to the wheel,
>
Not that much drag ..... unless you've got the brakes on. The tire is
rolling ..... or should be!!
> it causes the gearleg to flex to the back,
>
I'm missing something here. There is no vector to the back. The force
vector is to the outside on the heavy side.
> twisting the axle to the outside, increasing the toe-out. So as near as I can
tell,
>the heavy wheel on an RV will *always* have toe-out, unless you set it
>with *lots* of toe-in to start with.
>
You forget the increase in caster which is far, far, more than any
change in toe-in/out.
>Maybe this is exactly what's intended... With a slight "preload" of
>toe-in, in the case of a crosswind, one-wheel landing the gear flexes to
>give you toe-out, which stabilizes you. Once wheels are flat on the
>ground, and the speed has dropped, you go back to neutral or slight
>toe-in (but by that point it won't matter, as the danger of a groundloop
>is lessened, unless a dastardly gust comes out of nowhere...).
>
Again the effects of caster are ignored. Tip up the wing of your little
plastic airplane and see what happens to the caster.
>The RV gear project outwards and aftwards quite a bit, particularly in the
>three point position. As the wheels are weighted the axles move backwards
>and outwards and the wheel base gets wider. Its the wider that increases toe
>in. Imagine worse case by grabbing the gear ankles and pushing each towards
>the wing tips. The axles tips would move fwd and upwards.
>
>
>
>I can't argue with practical experience. Theory often falls down hard
>when shown that "it just doesn't work that way." But even when that
>happens, it's usually pretty simple to show that the reason the theory
>doesn't hold is because it's faulty. If it were just me, i'd bow to the
>practical experience of you and others who can explain quite eloquently
>what you've seen in practise. But every design textbook I can find says
>that toe-out (or neutral) is the "best" alignment for taildraggers. I
>would have expected that 50 years later someone would have found new
>theory to explain why the old theory is wrong.
>
Well, I concur with this paragraph. The problem here is that I've lost
track, due to the vagaries of email, just who said what in this email
>-Rob
><
>
>Not too sure about the old books, but most automotive books I've read call
>for slight toe-in. As far as I know the physics don't change just because
>you took the wings off.
>
The suspension on a car is as far removed from an aircraft suspension as
it can get. It's like the Penguin problem above.
>W
>
Wheeler, and Bob, Please don't take offense at my comments ..... none
was meant. I'm not here to change anyones mind, but my experience and
thought tell me that toe-in is not a good thing, and that caster has a
lot to do with suirrely landings.
Linn
Message 3
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--> RV-List message posted by: "Cy Galley" <cgalley@qcbc.org>
The loading on the steerable wheel is a real variable as it might not be
able to counteract any of the turning moments with a light load or less.
The loading of the wheels and the direction they go down the runway while
turning due to the center of gravity being so much higher in an airplane can
change. The aerodynamics of the plane may or may not have loading on the
wheels. This is not the case in a car to any great extent when traveling at
landing speeds. If there are any aerodynamic devices, they are fixed and do
not change like in a plane. The high center of gravity also changes the
braking loads on the plane wheels much more than in a car.
----- Original Message -----
From: "Wheeler North" <wnorth@sdccd.cc.ca.us>
Subject: RV-List: toe
> --> RV-List message posted by: Wheeler North <wnorth@sdccd.cc.ca.us>
>
> Time: 07:06:14 AM PST US
> From: "Cy Galley" <cgalley@QCBC.ORG>
> Subject: Re: RV-List: More on toe
>
> --> RV-List message posted by: "Cy Galley" <cgalley@qcbc.org>
>
> You have left out the effect of Center of Gravity and the dynamic controls
> in 3 axis instead of just the 2 of automotive.,
>
> Cy,
>
> I'm not sure I understand what you're getting at so I'll mull it around on
> paper here.
>
> Its not really a 3 axis issue for most of the landing/takeoff run. At
least
> I've never heard of an airplane that airlooped close to the runway. And I
> think I have been talking about the CG throughout most of this.
>
> The RVs tend to either be on the ground or in the air, but they don't
spend
> much time doing both, at least such that the third axis of motion
> complicates things a lot.
>
> So for say a 600 ft ground landing run, lets say you wheel land it and
then
> stick it forward, you're a car with wings after 15-20 feet at the most. In
a
> good three point plop, you're a car with wings after 5ft
>
> During takeoff there is a big fan helping to keep things pulled straight
> ahead, and again with an RV you go from being a weighted wheeled vehicle
to
> "what wheels" fairly quickly. This is also one arguement for doing wheel
> takeoffs rather than three point takeoffs. One transitions from loaded
mains
> to flying in about one second with a wheel takeoff.
>
> I will also add the the three axis effects that apply to an aircraft also
> apply to car and in fact may be worse for a car. The only difference is an
> aircraft has wings and inertia causing the vertical axis of force and
> movement, whereas the car only has inertia. But the car has a lot more
> opportunity for its inertia to be propelled vertically given that most
roads
> are far worse than most runways. And the aircraft's wings usually are
> helping to stabilize things as they begin to generate good lift.
>
> Am I still on the same page here??? I guess I got myself confused because
> I'm not clear what you were getting at Cy. ;{O
>
> W
>
>
Message 4
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--> RV-List message posted by: " bert murillo" <bert6@mybluelight.com>
Hi:
I bought the seats from Van's, so I could have
them upholstered.
That was a bad idea, wish I had go direct to any
of the people, that do this for the rv's...
First ,Laurentis, or the others, do not accept
Van's foam, to be upholster... I understand that.
Then when I looked around for one of the automovil
places, many did not wanted to even consider doing it..
Most said, they would do it with their own cutting
patter etc..
And ont that will do it, tells me that the foam will
be reduced some how, and that the measurement for the
seats, will be slighly less than the support seat...
What is he talking about... any of you that had
used Vans foam, had any trouble having the seats finished..
Any suggestions...
Bert
Do Not archive
Message 5
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--> RV-List message posted by: Tim Coldenhoff <rv9a_000@deru.com>
bert murillo wrote:
> --> RV-List message posted by: " bert murillo"
> I bought the seats from Van's, so I could have
> them upholstered.
>
> That was a bad idea, wish I had go direct to any
> of the people, that do this for the rv's...
I don't have an answer to your questions, however if
you can't find anyone else, take a look at:
www.classicaerodesigns.com
In addition to selling complete seat sets for RVs, he
will also upholster the Van's seat foam.
--
Tim Coldenhoff
www.deru.com/~rv9a
90338 - electrical/finishing
Message 6
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--> RV-List message posted by: "jim jewell" <jjewell@telus.net>
This is a test. do not archive
Message 7
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| Subject: | Build Wings Together or Separate? |
--> RV-List message posted by: "" <tx_jayhawk@excite.com>
Those with experience going both routes...is it as big time saver to build both
wings at the same time? Anyone have an estimate on the number of clecos required
per wing? I don't think I can get both wings on one stand, and I am trying
to understand if I should make the additional investment.
Thanks,
Scott
7A Wings
Join Excite! - http://www.excite.com
The most personalized portal on the Web!
Message 8
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--> RV-List message posted by: "Rob W M Shipley" <rob@robsglass.com>
Try http://www.atrim.com/Page97.html
Rob
Rob W M Shipley
N919RV (res) Fuselage .....still!
Subject: Re: RV-List: Great find on glare shield end cap/cover
--> RV-List message posted by: DWENSING@aol.com
In a message dated 2/6/04 9:42:27 AM Eastern Standard Time,
shempdowling@earthlink.net writes:
> heavy duty piece with some metal in it to keep a round shape.nbsp; It fit
> perfectly and looks great.nbsp; Its called Jiffy Trim and I got it at a
> local fabric shop in Louisville, www.Baerfabrics.com
Jeff,
Could not find it on their web site even searching the name Jiffy Trim. Is
there more to the name?
Dale Ensing
do not archive
Message 9
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| Subject: | What size is GPS coax? |
--> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
I need to shorten my Garmin 295 remote antenna wire. Garmin says it is ok to shorten
it, but I cannot find a BNC to fit this small of a wire.
Guess I will have to special order it. Anyone know what size coax this is? {ie.,
RF58, RG6, etc.}
Thanks,
Jerry Calvert
Edmond Ok
RV6 N296JC
Message 10
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| Subject: | What size is GPS coax? |
--> RV-List message posted by: "Larry Bowen" <Larry@BowenAero.com>
A typical BNC should do. See an example here:
http://www.aeroelectric.com/articles/RG58/RG58.html
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
> -----Original Message-----
> From: Jerry Calvert [mailto:rv6@cox.net]
> Sent: Sunday, February 08, 2004 12:40 AM
> To: rv-list@matronics.com
> Subject: RV-List: What size is GPS coax?
>
>
> --> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
>
> I need to shorten my Garmin 295 remote antenna wire. Garmin
> says it is ok to shorten it, but I cannot find a BNC to fit
> this small of a wire.
>
> Guess I will have to special order it. Anyone know what size
> coax this is? {ie., RF58, RG6, etc.}
>
> Thanks,
> Jerry Calvert
> Edmond Ok
> RV6 N296JC
Message 11
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| Subject: | Re: What size is GPS coax? |
--> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
Thanks for the tip Larry.
Jerry Calvert
RV6
do not archive
----- Original Message -----
From: "Jerry Calvert" <rv6@cox.net>
Subject: RV-List: What size is GPS coax?
> --> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
>
> I need to shorten my Garmin 295 remote antenna wire. Garmin says it is ok
to shorten it, but I cannot find a BNC to fit this small of a wire.
>
> Guess I will have to special order it. Anyone know what size coax this
is? {ie., RF58, RG6, etc.}
>
> Thanks,
> Jerry Calvert
> Edmond Ok
> RV6 N296JC
>
>
Message 12
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| Subject: | What size is GPS coax? |
--> RV-List message posted by: "Stein Bruch" <stein@steinair.com>
Just an FYI, if you are talking about the "thin coax" (MCX) that some of the
Garmin/Skyforce/et.al GPS's use, it's NOT regular sized Coax cable like
RG400/RG142/RG58.
If it appears to be about half the size or less, than it's probably
"MCX-Micro Coax" cable, which is used extensively on may GPS portable
antennas. If the connector is a typical BNC, than your cable is probably
full sized coax, and you should be able to just chop it off and use another
crimp on BNC.
That being said, if the cable is very thin and you chop it off, you'll need
a different BNC or MCX connector. If you GPS doesn't take a BNC (SOME
portables DON'T) you'll need an MCX (micro coaxial) connector.
I don't know right off hand where to get the MCX connectors.
Just my 2 cents as usual!
Cheers,
Stein Bruch
RV6's, Minneapolis
http://www.steinair.com
-----Original Message-----
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com]On Behalf Of Jerry Calvert
Subject: Re: RV-List: What size is GPS coax?
--> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
Thanks for the tip Larry.
Jerry Calvert
RV6
do not archive
----- Original Message -----
From: "Jerry Calvert" <rv6@cox.net>
Subject: RV-List: What size is GPS coax?
> --> RV-List message posted by: "Jerry Calvert" <rv6@cox.net>
>
> I need to shorten my Garmin 295 remote antenna wire. Garmin says it is ok
to shorten it, but I cannot find a BNC to fit this small of a wire.
>
> Guess I will have to special order it. Anyone know what size coax this
is? {ie., RF58, RG6, etc.}
>
> Thanks,
> Jerry Calvert
> Edmond Ok
> RV6 N296JC
>
>
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