Today's Message Index:
----------------------
1. 04:57 AM - Re: Adding wheel pants. (Boilermaker2000)
2. 01:24 PM - Bungee gear limit cables (was) Re: model 5 gear pictures (Lowell Fitt)
3. 04:29 PM - Re: model 5 gear pictures (Joel)
4. 10:23 PM - Re: Bungee gear limit cables (was) Re: model 5 gear pictures (bjones@dmv.com)
5. 11:45 PM - Re: model 5 gear pictures (akflyer)
Message 1
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| Subject: | Re: Adding wheel pants. |
Yodaone,
Did you ever get any info or pics on how to install the wheel pants?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=247785#247785
Message 2
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| Subject: | Re: Bungee gear limit cables (was) Re: model 5 gear pictures |
Hi Bob,
What advice are you having trouble with? I stated a fact - I do have
friends that removed the limit cables - and then made a suggestion.
For the Limit Cable fans, I did some research and made a drawing or two and
made some calculations.
First, Mil-C-5651D Load Specifications for our Type III Bungee cord call
for a load range at 100% elongation of between 90 lbs. and 150 lbs. A
minimum stretch at 140% and an ultimate breaking load of 300 lbs. For those
concerned with the 300 lbs, remember that we have six turns and 12 lengths
of bungee supporting our landing gear.
Using the drawings, it appears that a stretch of 140% would drop the height
of the fuselage at the gear, about 7" or maybe 9" at the prop in the three
point or the original 7" wheel landing. (It has been a long time since I had
a Model IV on the original bungee gear, but pictures I have of numarous
airplanes show the ground clearance in the three point to be well over half
a prop blade length.)
Given a load at the100% stretch to be at the low end - 90 lbs multiplied by
12 would be 1080 lbs. Per gear leg or close to 2 Gs if all the max gross wt.
was on the mains. This would result in a bungee cord drop of about 3 inches
or a nose drop of about five inches. (Mayabe this is where the manual
illustration measurement comes from - see below). Calculating at the high
end of 150 lbs. the 100% stretch load would be 1800 lbs. at max gross and
all weight on the mains or 3Gs. to get the same drop. It is likely that the
bungees we have - if relatively fresh would give a load somewhere between
these figures.
Most of this stuff is meaningless except regarding the length of the limit
cables. The manual - my manual - calls for a length of 4.5 to 5 inches. The
drawing shows 3 inches. The drop at the bungees at the 140" stretch would be
closer to six inches. If your limit cables are in the 4.5 to 5 inch range,
or worse yet, installed at the 3 inches in the drawing, you are cutting the
bungees effective spring action to a fraction of what it is designed to
handle and the sudden stop of "spring" movement focused on the bungee
bulkhead has in the past and likely will in the future, cause damage to the
most difficult to repair structural element.
I mentioned that some have removed the limit cables. I don't recall
recommending that as was asserted, but I did recommend lengthening them.
Frankly with a little bit of effort, I think I can now fairly safely suggest
that removing them would result in minimal risk to the prop, but can't say
much about the wing tips if someone manages to put 3gs of force on one gear
leg, but I think I would strongly recommend that they be long enough to
allow for at least six inches of downward movement of the bungee attachment
tube. If someone else wants to do the work and comes up with different
numbers, I am willing to listen.
Better landings? Definitely good advice.
Lowell Fitt
Cameron Park, CA
Model IV-1200 R-912 UL
Covering.
----- Original Message -----
From: "AKFLYERBOB" <r.wolfejr@worldnet.att.net>
Sent: Thursday, June 11, 2009 8:31 AM
Subject: Kitfox-List: Re: model 5 gear pictures
> <r.wolfejr@worldnet.att.net>
>
> Thats bad advice
> The cables are to keep the prop and "WING" from hitting
> the ground. Even with broken bungees and bent gear
> you can still fly home on the safety cable.
> What should be eliminated is the HARD LANDINGS if possible.
> Bob
>
> --------
> Bob Wolfe..Soldotna, Alaska
> KF Mod I and III
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=247687#247687
>
>
>
Message 3
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| Subject: | Re: model 5 gear pictures |
A few more model 5 landing gear pix
--------
Joel Mapes Kitfox 5 912 ULS Aerocomp amphibs
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=247891#247891
Attachments:
http://forums.matronics.com//files/dscf0005_558.jpg
http://forums.matronics.com//files/dscf0004_712.jpg
http://forums.matronics.com//files/dscf0003_160.jpg
http://forums.matronics.com//files/dscf0002_114.jpg
http://forums.matronics.com//files/dscf0001_674.jpg
Message 4
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| Subject: | Re: Bungee gear limit cables (was) Re: model 5 gear pictures |
Lowel
I have heard about three failures of relatively NEW bungees in Kitfox
installations. In one instance the gear safety cable failed after the bungee
failed. The result was a ground loop and wing damage.
Apparently there was no structural damage caused by the safety cables in those
three cases although we have heard of it in other cases.
I don't know what caused the bungee failures but suspect fraying, installation
error or bungee end failure.
If there is a moral here, it may be that Murphy can show up in a variety
of "unexpected" ways in addition to the expected hard landing and in bungee
failures not caused by hard landings the safety cables could be valuable.
As an aside, I too installed longer cables during my last bungee replacement.
BJ
N154K N626NR
bjones@dmv.com
443-480-1023
Quoting Lowell Fitt <lcfitt@sbcglobal.net>:
>
> Hi Bob,
>
> What advice are you having trouble with? I stated a fact - I do have
> friends that removed the limit cables - and then made a suggestion.
>
> For the Limit Cable fans, I did some research and made a drawing or two and
> made some calculations.
> First, Mil-C-5651D Load Specifications for our Type III Bungee cord call
> for a load range at 100% elongation of between 90 lbs. and 150 lbs. A
> minimum stretch at 140% and an ultimate breaking load of 300 lbs. For those
> concerned with the 300 lbs, remember that we have six turns and 12 lengths
> of bungee supporting our landing gear.
>
> Using the drawings, it appears that a stretch of 140% would drop the height
> of the fuselage at the gear, about 7" or maybe 9" at the prop in the three
> point or the original 7" wheel landing. (It has been a long time since I had
>
> a Model IV on the original bungee gear, but pictures I have of numarous
> airplanes show the ground clearance in the three point to be well over half
> a prop blade length.)
>
> Given a load at the100% stretch to be at the low end - 90 lbs multiplied by
> 12 would be 1080 lbs. Per gear leg or close to 2 Gs if all the max gross wt.
>
> was on the mains. This would result in a bungee cord drop of about 3 inches
>
> or a nose drop of about five inches. (Mayabe this is where the manual
> illustration measurement comes from - see below). Calculating at the high
> end of 150 lbs. the 100% stretch load would be 1800 lbs. at max gross and
> all weight on the mains or 3Gs. to get the same drop. It is likely that the
>
> bungees we have - if relatively fresh would give a load somewhere between
> these figures.
>
> Most of this stuff is meaningless except regarding the length of the limit
> cables. The manual - my manual - calls for a length of 4.5 to 5 inches. The
> drawing shows 3 inches. The drop at the bungees at the 140" stretch would be
>
> closer to six inches. If your limit cables are in the 4.5 to 5 inch range,
> or worse yet, installed at the 3 inches in the drawing, you are cutting the
> bungees effective spring action to a fraction of what it is designed to
> handle and the sudden stop of "spring" movement focused on the bungee
> bulkhead has in the past and likely will in the future, cause damage to the
> most difficult to repair structural element.
>
> I mentioned that some have removed the limit cables. I don't recall
> recommending that as was asserted, but I did recommend lengthening them.
> Frankly with a little bit of effort, I think I can now fairly safely suggest
>
> that removing them would result in minimal risk to the prop, but can't say
> much about the wing tips if someone manages to put 3gs of force on one gear
> leg, but I think I would strongly recommend that they be long enough to
> allow for at least six inches of downward movement of the bungee attachment
> tube. If someone else wants to do the work and comes up with different
> numbers, I am willing to listen.
>
> Better landings? Definitely good advice.
>
> Lowell Fitt
> Cameron Park, CA
> Model IV-1200 R-912 UL
> Covering.
>
> ----- Original Message -----
> From: "AKFLYERBOB" <r.wolfejr@worldnet.att.net>
> To: <kitfox-list@matronics.com>
> Sent: Thursday, June 11, 2009 8:31 AM
> Subject: Kitfox-List: Re: model 5 gear pictures
>
>
> > <r.wolfejr@worldnet.att.net>
> >
> > Thats bad advice
> > The cables are to keep the prop and "WING" from hitting
> > the ground. Even with broken bungees and bent gear
> > you can still fly home on the safety cable.
> > What should be eliminated is the HARD LANDINGS if possible.
> > Bob
> >
> > --------
> > Bob Wolfe..Soldotna, Alaska
> > KF Mod I and III
> >
> >
> >
> >
> > Read this topic online here:
> >
> > http://forums.matronics.com/viewtopic.php?p=247687#247687
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
------------------------------------------------------
This message was sent using Delmarva Online's Webmail.
http://www.delmarvaonline.com/
Message 5
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| Subject: | Re: model 5 gear pictures |
One suggestion based on personal experience. Dont put the safety cable on the
end of the gear leg like yours is now. Put it inside the cluster where the rear
kicker comes in. My Avid, and my Brothers kitfox BOTH had a gear failure from
cracking that started at the toe of the weld where the rear tube comes in.
With the bungies on you cant see the cracks starting. On my Avid the result
was the leg broke off and the cable had nothing to hold up so over he went (but
I did get a damn good deal on a bent airplane because that was the second time
it had happened and he was not able to repair it the second time). On my
brother KF II the exact same thing happened but we were both in it. bounced a
little but not bad, when he came back down the gear folded and over we went.
Kinda ruined the day for us both and cost a few bucks for him to fix. It could
have been prevented in both cases if the safety cable was located in an area
that was not prone to breaking. If you have to change the gear, you would have
to cut the cables, but that is a very small price to pay to keep the bird
in one piece in the event of a gear failure.
--------
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 IVO IFA
Full Lotus 1260
#1 snake oil salesman since 1-22-2009
hander outer of humorless darwin awards
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=247920#247920
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