Today's Message Index:
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1. 12:05 AM - Re: Gear leg toe-in (Peter and Jan Disher)
2. 04:32 AM - Re: Gear leg shimmy experiments (Malcolm Ferguson)
3. 06:20 AM - Re: Gear leg shimmy experiments (N1BZRich@aol.com)
4. 11:35 AM - Re:Gear leg shimmy experiments (EAFerguson@aol.com)
5. 02:35 PM - Re: Re:Gear leg shimmy experiments (JOSEPH MATHIAS LINDA MATHIAS)
6. 10:06 PM - Re: Re:Gear leg shimmy experiments (N1BZRich@aol.com)
7. 10:08 PM - Re: Re:Gear leg shimmy experiments (N1BZRich@AOL.COM)
Message 1
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| Subject: | Re: Gear leg toe-in |
Yes Buz, I also used a lesser figure of 1 1/4". Maybe when the load goes
on the toe in moves towards toe out, I'l re check it when I'm finished
and ready to fly for curiosity sake.
Pete D
----- Original Message -----
From: N1BZRich@aol.com
To: lightning-list@matronics.com
Sent: Saturday, January 05, 2008 4:17 PM
Subject: Re: Lightning-List: Gear leg toe-in
Pete, your math is right. When we recently adjusted Linda's I think I
remember using 1" at 58" for 1 degree. I don't have the manual in front
of me, but the numbers you quoted would give over 2 degrees. Some other
important parts of setting the toe is to have some weight in the cockpit
(not sure what amount the manual recommends) so that you have the gear
legs spread to a normal position. Then make sure the centerline of the
aircraft does not move while you do the measurements for toe. One
technique (if you don't have the jig that they use at the factory) is to
drop a plumb bob from the nose and tail then use a chalk line to connect
the two spots. This line establishes the CL of the aircraft on the
hangar floor. Then measure out perpendicular from that center line to
the centerline of each main tire. That then becomes the start point for
setting the 1" at 58". Of course, you probably already knew all of
this.
Buz
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Start the year off right. Easy ways to stay in shape in the new year.
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4/01/2008 12:05 PM
Message 2
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| Subject: | Re: Gear leg shimmy experiments |
Hi Buz and all,
The major dislike of my Esqual is the small fuel capacity 70 litres and was
the main reason the early Lightning held no appeal to me till they made the
bigger tanks available. Can't help you with the source of info as I monitor
a number of lists and it was 18 months ago or so. We put on about 100 hours
a year on average. The prop is a Rospeller electric C/S with Helix carbon
fibre scimitar blades. The performance is very good but I don't think I
would buy another one next time. There has been 2 props shed blades here in
OZ due maybe to a design that requires very accurate torqueing of the prop
blade hubs. Also has a 600 hour TBO. Would maybe plump for a
Kremin(Woodcomp). This prop can be ordered with reversing blades. Now
wouldn't that make for a short landing. Have had a lot of trouble with the
electric servo motor/gearbox(made in Italy). Have modified it and no more
trouble since. Prop was dynamically balanced in flight and is very smooth.
I generally cruise at 137-140 kts at 5200 revs and full throttle. Get the
better speed at low altitude and cool airtemps. Will do 145 kts at 5500
which is max continuous cruise revs but the noise level goes up appreciably.
Interestingly taking the rear wheel fairings off only has a small reduction
in speed so they are not drag efficient.
As regards wheel shimmy, it was a saga. The front wheel rotates in flight
and required very accurate balancing to eliminate vibration. I put it up
against a bench grinder spinning at 2800 rpm, holding the axle in my
fingers. Its possible to get no out of balance vibration by trial and error.
The rear wheels I balance on a purpose built hub with the seals and grease
removed from the bearings then a tad of diesel fuel in the bearings. After
this I realized that wheel shimmy had nothing to do with wheel balance in my
case.
I think you are on the right track with toe adjustment and strengthening the
legs although the later only masks the problem.
Eric Jones has a good article on his website on nose wheel shimmy.
http://www.periheliondesign.com/downloads/nosewheelshimmy.pdf
Having problems with home built aircraft generates good list traffic eg
Europa, so I suppose it says somehing about the Lightning that the list is a
bit quiet.
Malcolm Ferguson
Message 3
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| Subject: | Re: Gear leg shimmy experiments |
In a message dated 1/5/2008 7:33:17 A.M. Eastern Standard Time,
malannx@bigpond.com writes:
The major dislike of my Esqual is the small fuel capacity 70 litres
Am I reading this right, only 70 litres or about 18.5 gallons? My Esqual
(on a cold day) will hold a little over 29 gallons or something like 110
litres. You must have the very early Esqual wings. I can see why that would
be an
operational problem on cross country flights. As to props, I am currently
running a fixed pitch Sensenich (64ZK56) and it is still not enough prop as I
can over speed the 3300 Jabiru by over 100 RPM when running full throttle at
5,000', so another prop is on order. But this prop allows me to cruise at
altitude (say 8 to 10K feet) at a little over 150 knots true burning slightly
less than 6 gallons per hour. Down on the deck (I live at sea level) when I
have smooth air I can see 180 knots and still pulling the throttle back to
keep below red line rpm. This prop still gives me over 1000 feet per minute
climb rate at gross and short TO rolls even on a hot day. The purpose of the new
prop is to optimize cruise efficiency (speed vs. fuel burn).
Buz
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
Message 4
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| Subject: | Re:Gear leg shimmy experiments |
I've been reading this thread with interest. As I have told Buz, I'm get
hardly any gear shimmy with my Light Sport Version Lightning (no spats or strut
fairings). Since it only happens occasionally, and is very brief, I haven't
thought about a cure. For the record, how are the other LSA Lightnings doing?
Is this something that only affects birds with full gear clean up hardware?
While the answer may be obvious, more weight brings on more shimmy, I think
that point is worth documenting. Would the other Light Sporters chime in
please.
Earl Ferguson
N17EF
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
Message 5
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| Subject: | Re:Gear leg shimmy experiments |
Earl,
Although my Lightning isn't a LSA, I have checked the shimmy both
with and without gear fairings and wheel pants. I currently have the
fairings and wheel pants off and there seems to be no noticeable
difference if it's wearing them or not; the vibration doesn't seem any
different. Initially it started about 17 MPH; after decreasing tire
pressure to 23-25 it starts about 22 MPH. Now with the gear leg
stiffeners, it takes about 25 MPH to notice the vibration.
Linda
----- Original Message -----
From: EAFerguson@aol.com
To: lightning-list@matronics.com
Sent: Saturday, January 05, 2008 2:29 PM
Subject: Lightning-List: Re:Gear leg shimmy experiments
I've been reading this thread with interest. As I have told Buz, I'm
get hardly any gear shimmy with my Light Sport Version Lightning (no
spats or strut fairings). Since it only happens occasionally, and is
very brief, I haven't thought about a cure. For the record, how are the
other LSA Lightnings doing? Is this something that only affects birds
with full gear clean up hardware? While the answer may be obvious, more
weight brings on more shimmy, I think that point is worth documenting.
Would the other Light Sporters chime in please.
Earl Ferguson
N17EF
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Start the year off right. Easy ways to stay in shape in the new
year.
-------------------------------------------------------------------------
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Message 6
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| Subject: | Re:Gear leg shimmy experiments |
In a message dated 1/5/2008 2:36:37 P.M. Eastern Standard Time,
EAFerguson@aol.com writes:
While the answer may be obvious, more weight brings on more shimmy, I think
that point is worth documenting.
Earl,
Your above statement is not what I have seen on 31BZ. For me it is
slightly worse at lighter weights. But as in anything having to do with
aviation, your mileage may vary.
Buz
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
Message 7
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| Subject: | Re:Gear leg shimmy experiments |
In a message dated 1/5/2008 5:37:05 P.M. Eastern Standard Time,
lbmathias@verizon.net writes:
Now with the gear leg stiffeners, it takes about 25 MPH to notice the
vibration.
Linda,
So you did see shimmy on your next flight. Bummer. Was there any
improvement with the stiffeners, meaning was the shimmy any less than it is
without stiffeners?
Buz
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
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