Today's Message Index:
----------------------
1. 02:59 PM - Re: Replacement tail rod...? (Jack Hart)
2. 04:25 PM - Re: Re: Replacement tail rod...? (John Hauck)
3. 09:11 PM - Re: Re: Replacement tail rod...? (Jack Hart)
Message 1
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| Subject: | Re: Replacement tail rod...? |
John, I don't understand your statement. The cables are designed to
help in the case of a "plop" and do nothing to prevent the gear from
flexing or bending front to back and/or inward. If you drop a wheel into a
hole, the leg will bend just as it would before the cable system was
installed and protects the fuselage from being damaged. If I recall
correctly, the whole works weighed a few ounces. I put up the previous
jump to show that no modifications need to be made to the existing
structures and that cables could be used to keep the gear from spreading.
$20 spent and the time required to fabricate parts seemed like a good
trade off in comparison to straightening and/or purchasing and installing
new legs. http://www.jackbhart.com/firefly/firefly134.html In case
you missed it, I put up the above jump so that you can view the analysis
that was done to determine if adding cables would be beneficial. These
calculations indicated the original leg would start to bend at 1.8 G in a
level straight two wheel plop. With the cable system in place and
assuming a plop hard enough to cause cable failure, the cable and gear leg
system will withstand a 5.2 G plop. Jack B. Hart, FF004 Winchester,
IN ---------------------------------------- From: "John Hauck"
<jhauck@elmore.rr.com> Sent: Thursday, February 22, 2018 12:18 PM To:
kolb-list@matronics.com Subject: RE: Kolb-List: Re: Replacement tail
rod...? Jack H's cables will probably prevent spreading the main gear,
but effectively kill the suspension.
Message 2
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| Subject: | Re: Replacement tail rod...? |
Jack H/Kolbers:
By adding cables and restricting outward flex of the gear legs, your
modification effectively kills the spring in the direction it is needed
most, outward. To me, what you have done is change flexible gear to rigid
gear.
I went to 1 1/8" 7075 after my initial taxi when I bent the 1" 7075 legs
before I got a chance to fly. 1 1/8" didn't hack it either, which proved to
me that 7075 rod didn't make good spring gear. Heat treated 4130 has proven
much better, although I can bend them too when I try.
Spring gear is much easier on the aircraft than rigid.
>From the photo of your airplane, it is obvious you landed on the right gear,
putting all the load on one leg. I do that too, but on the left leg.
john h
mkIII
Titus, Alabama
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of Jack Hart
Sent: Sunday, February 25, 2018 4:59 PM
Subject: Kolb-List: Re: Replacement tail rod...?
John,
I don't understand your statement. The cables are designed to help in the
case of a "plop" and do nothing to prevent the gear from flexing or bending
front to back and/or inward. If you drop a wheel into a hole, the leg will
bend just as it would before the cable system was installed and protects
the fuselage from being damaged. If I recall correctly, the whole works
weighed a few ounces.
I put up the previous jump to show that no modifications need to be made
to the existing structures and that cables could be used to keep the
gear from spreading. $20 spent and the time required to fabricate parts
seemed like a good trade off in comparison to straightening and/or
purchasing and installing new legs.
http://www.jackbhart.com/firefly/firefly134.html
In case you missed it, I put up the above jump so that you can view the
analysis that was done to determine if adding cables would be beneficial.
These calculations indicated the original leg would start to bend at 1.8 G
in a level straight two wheel plop. With the cable system in place and
assuming a plop hard enough to cause cable failure, the cable and gear leg
system will withstand a 5.2 G plop.
Jack B. Hart, FF004
Winchester, IN
----------------------------------------
From: "John Hauck" <jhauck@elmore.rr.com>
Sent: Thursday, February 22, 2018 12:18 PM
Subject: RE: Kolb-List: Re: Replacement tail rod...?
Jack H's cables will probably prevent spreading the main gear, but
effectively kill the suspension.
Message 3
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| Subject: | Re: Replacement tail rod...? |
John,
I believe you have it right. The FireFly gear is rigid by design and the
aluminum leg bends so easily. If you apply a 330 pound load in any
direction at the axle, the leg will bend at just below the fuselage socket.
By adding the cable I have, indeed, reduced one degree of flexsure and
gained some freedom from plops.
As for the photo, it is difficult to tell if it was or was not a level
plop. At the time it felt like it was. Both legs had to be straightened.
It could be that the right tire broke loose from the asphalt first.
Jack B Hart FF004
Winchester, IN
----------------------------------------
From: "John Hauck" <jhauck@elmore.rr.com>
Sent: Sunday, February 25, 2018 7:28 PM
Subject: RE: Kolb-List: Re: Replacement tail rod...?
Jack H/Kolbers:
By adding cables and restricting outward flex of the gear legs, your
modification effectively kills the spring in the direction it is needed
most, outward. To me, what you have done is change flexible gear to rigid
gear.
Spring gear is much easier on the aircraft than rigid.
>From the photo of your airplane, it is obvious you landed on the right
gear, putting all the load on one leg. I do that too, but on the left leg.
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