Today's Message Index:
----------------------
1. 11:05 AM - Nose gear inspections (GREGSMI@aol.com)
2. 11:17 AM - Re: Nose gear inspections (Bernard Wilder)
3. 12:56 PM - Re: Nose gear inspections (Brian Anderson)
4. 02:17 PM - Re: Nose gear inspections (GREGSMI@aol.com)
5. 02:45 PM - Re: Nose gear inspections (GREGSMI@aol.com)
Message 1
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| Subject: | Nose gear inspections |
I have notice we are seeing some reports of nose gear failures. I know of
three in the US and two in Europe. Recently we were able to recover all the
parts and do an analysis. The results are inconclusive at this point, but
what is known is the spindle shaft broke in fatigue. We do not know what
started the cycle, hard landing, fast landing and hard braking, but at this
point, we do know that it would be smart to include the nose gear in your
inspection routine. This will involve you removing the fork and checking the
spindle shaft. If it is not straight, it probably should be suspect and
appropriate action taken.
Several people have designed new spindles, my self included. One is posted
on the Yahoo group site pictures. I have been flying my Pulsar since 1996,
1400 hours, with no sign of a problem, but I have decided to replace the
spindle with my own design I am having made out of one inch 4130 heat treated
to 150KSI. I am doing this because the fatigue failures I have seen have
happened up inside the collar where you cannot see, so the only detection is
if the spindle is bent. I know, over the years I have flown my aircraft I
have unintentionally bounced the nose so I decided to replace it now
rather than risk the aircraft. For me, I hate cutting up a part that has served
me so well for so many years, but I do not want to look back and say I
suspected this might happen.
Now I know you tail dragger fans out there will have a field day with this,
and that is OK, but please do take this note seriously. I do not want to
read about anyone getting hurt because of a failure. These are experimental
aircraft, and in the Pulsar case, totally without factory support, so it is
up to the owner to decide what they should do. In most cases, you are the
manufacture of the aircraft. I am taking a conservative approach and
rebuilding mine in such a way that it is easily inspected and will be stronger
than the original design.
Be safe.
Greg
Message 2
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| Subject: | Re: Nose gear inspections |
Greg,
Are the suspect nose gesrs the ones that Aero Design furnished, the ones
from Sky Star, or both ? ? ? ?
Regards to you and Donna.
Bernie
On Thu, Mar 28, 2013 at 2:04 PM, <GREGSMI@aol.com> wrote:
> **
> I have notice we are seeing some reports of nose gear failures. I know
> of three in the US and two in Europe. Recently we were able to recover all
> the parts and do an analysis. The results are inconclusive at this point,
> but what is known is the spindle shaft broke in fatigue. We do not know
> what started the cycle, hard landing, fast landing and hard braking, but at
> this point, we do know that it would be smart to include the nose gear in
> your inspection routine. This will involve you removing the fork and
> checking the spindle shaft. If it is not straight, it probably should be
> suspect and appropriate action taken.
>
> Several people have designed new spindles, my self included. One is posted
> on the Yahoo group site pictures. I have been flying my Pulsar since 1996,
> 1400 hours, with no sign of a problem, but I have decided to replace the
> spindle with my own design I am having made out of one inch 4130 heat
> treated to 150KSI. I am doing this because the fatigue failures I have seen
> have happened up inside the collar where you cannot see, so the only
> detection is if the spindle is bent. I know, over the years I have flown my
> aircraft I have unintentionally bounced the nose so I decided to replace
> it now rather than risk the aircraft. For me, I hate cutting up a part that
> has served me so well for so many years, but I do not want to look back and
> say I suspected this might happen.
>
> Now I know you tail dragger fans out there will have a field day with
> this, and that is OK, but please do take this note seriously. I do not want
> to read about anyone getting hurt because of a failure. These are
> experimental aircraft, and in the Pulsar case, totally without factory
> support, so it is up to the owner to decide what they should do. In most
> cases, you are the manufacture of the aircraft. I am taking a conservative
> approach and rebuilding mine in such a way that it is easily inspected and
> will be stronger than the original design.
>
> Be safe.
> Greg
>
> *
>
> *
>
>
Message 3
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| Subject: | Re: Nose gear inspections |
I'm interested in the effect of a modification I had to make to the nose
gear leg before I completed my Pulsar. The original cast aluminium fork
supplied in the kit had the pivot hole drilled on a slight angle, which
resulted in a rather odd looking wheel tilt when the nose wheel was
mounted. I ordered a replacement from Skystar, and by that time they had
increased the diameter of the pivot, so the bushing in the casting was a
larger size. I had a sleeve made to fit over the original pivot and this
was heat shrunk into place. It's a long time ago, but I think the pivot
is now 3/4" diameter, rather than the original 5/8" diameter. I think
the whole casting was thicker too, which meant that I had to alter the
arrangement of bell view washers to get an acceptable solution.
The result has performed well. I've probably done about 600 landings on
seal and on grass [some pretty rough grass], and also on a rough strip
in the mountains where the large round stones were hidden by long grass.
Scary!!
Is it possible with this modification that the stresses in the spindle
are a little less, leading to a longer fatigue life. Maybe - - - maybe
not.
Brian
On 29/03/2013, at 7:04 AM, GREGSMI@aol.com wrote:
> I have notice we are seeing some reports of nose gear failures. I know
of three in the US and two in Europe. Recently we were able to recover
all the parts and do an analysis. The results are inconclusive at this
point, but what is known is the spindle shaft broke in fatigue. We do
not know what started the cycle, hard landing, fast landing and hard
braking, but at this point, we do know that it would be smart to include
the nose gear in your inspection routine. This will involve you removing
the fork and checking the spindle shaft. If it is not straight, it
probably should be suspect and appropriate action taken.
>
> Several people have designed new spindles, my self included. One is
posted on the Yahoo group site pictures. I have been flying my Pulsar
since 1996, 1400 hours, with no sign of a problem, but I have decided to
replace the spindle with my own design I am having made out of one inch
4130 heat treated to 150KSI. I am doing this because the fatigue
failures I have seen have happened up inside the collar where you cannot
see, so the only detection is if the spindle is bent. I know, over the
years I have flown my aircraft I have unintentionally bounced the nose
so I decided to replace it now rather than risk the aircraft. For me, I
hate cutting up a part that has served me so well for so many years, but
I do not want to look back and say I suspected this might happen.
>
> Now I know you tail dragger fans out there will have a field day with
this, and that is OK, but please do take this note seriously. I do not
want to read about anyone getting hurt because of a failure. These are
experimental aircraft, and in the Pulsar case, totally without factory
support, so it is up to the owner to decide what they should do. In most
cases, you are the manufacture of the aircraft. I am taking a
conservative approach and rebuilding mine in such a way that it is
easily inspected and will be stronger than the original design.
>
> Be safe.
> Greg
>
>
>
Message 4
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| Subject: | Re: Nose gear inspections |
The ones that cam from Aerodesigns are the ones I am dealing with. I
suspect that the fatigue cracking is started by a single incident of
overloading. After that, it slowly progresses until failure. But again, this is
just
speculation, only know for sure that the failures appear to progress over
time.
Greg
In a message dated 3/28/2013 12:18:09 P.M. Central America Standard ,
bernard.wilder2@gmail.com writes:
Greg,
Are the suspect nose gesrs the ones that Aero Design furnished, the ones
from Sky Star, or both ? ? ? ?
Regards to you and Donna.
Bernie
On Thu, Mar 28, 2013 at 2:04 PM, <_GREGSMI@aol.com_
(mailto:GREGSMI@aol.com) > wrote:
I have notice we are seeing some reports of nose gear failures. I know of
three in the US and two in Europe. Recently we were able to recover all the
parts and do an analysis. The results are inconclusive at this point, but
what is known is the spindle shaft broke in fatigue. We do not know what
started the cycle, hard landing, fast landing and hard braking, but at this
point, we do know that it would be smart to include the nose gear in your
inspection routine. This will involve you removing the fork and checking the
spindle shaft. If it is not straight, it probably should be suspect and
appropriate action taken.
Several people have designed new spindles, my self included. One is posted
on the Yahoo group site pictures. I have been flying my Pulsar since 1996,
1400 hours, with no sign of a problem, but I have decided to replace the
spindle with my own design I am having made out of one inch 4130 heat
treated to 150KSI. I am doing this because the fatigue failures I have seen have
happened up inside the collar where you cannot see, so the only detection
is if the spindle is bent. I know, over the years I have flown my aircraft I
have unintentionally bounced the nose so I decided to replace it now
rather than risk the aircraft. For me, I hate cutting up a part that has served
me so well for so many years, but I do not want to look back and say I
suspected this might happen.
Now I know you tail dragger fans out there will have a field day with
this, and that is OK, but please do take this note seriously. I do not want to
read about anyone getting hurt because of a failure. These are experimental
aircraft, and in the Pulsar case, totally without factory support, so it
is up to the owner to decide what they should do. In most cases, you are the
manufacture of the aircraft. I am taking a conservative approach and
rebuilding mine in such a way that it is easily inspected and will be stronger
than the original design.
Be safe.
Greg
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Message 5
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| Subject: | Re: Nose gear inspections |
Brian, the failures I have seen are, the 5/8 inch bolt shears inside the
collar that is welded to the 1 inch strut. I do not think that has anything
to do with the fork. Maybe it is absorbing more stress in the inserts, but
really do not know.
The ones I have seen are the stock 5/8 inch spindle bolts failing inside
the collar. If you have that arrangement, I would start checking it
immediately just to make sure the bolt is not bent. Even then, I am not sure that
is
the only criteria for failure, but if it is bent, that is a sure sign it
has been stressed beyond limits. Will it fail, I do not know because all the
failures I have seen are up inside the collar. That is why I have decided
to replace mine. I cannot see if there is any fatigue cracks.
I wish I could have more information but I have shared everything I know
and what I am doing. I just hope that passing this information along gives
everyone a new point to inspect and be safe.
Greg
In a message dated 3/28/2013 1:56:34 P.M. Central America Standard T,
briana@xtra.co.nz writes:
I'm interested in the effect of a modification I had to make to the nose
gear leg before I completed my Pulsar. The original cast aluminium fork
supplied in the kit had the pivot hole drilled on a slight angle, which
resulted in a rather odd looking wheel tilt when the nose wheel was mounted. I
ordered a replacement from Skystar, and by that time they had increased the
diameter of the pivot, so the bushing in the casting was a larger size. I had
a sleeve made to fit over the original pivot and this was heat shrunk into
place. It's a long time ago, but I think the pivot is now 3/4" diameter,
rather than the original 5/8" diameter. I think the whole casting was
thicker too, which meant that I had to alter the arrangement of bell view washers
to get an acceptable solution.
The result has performed well. I've probably done about 600 landings on
seal and on grass [some pretty rough grass], and also on a rough strip in the
mountains where the large round stones were hidden by long grass. Scary!!
Is it possible with this modification that the stresses in the spindle are
a little less, leading to a longer fatigue life. Maybe - - - maybe not.
Brian
On 29/03/2013, at 7:04 AM, _GREGSMI@aol.com_ (mailto:GREGSMI@aol.com)
wrote:
I have notice we are seeing some reports of nose gear failures. I know of
three in the US and two in Europe. Recently we were able to recover all the
parts and do an analysis. The results are inconclusive at this point, but
what is known is the spindle shaft broke in fatigue. We do not know what
started the cycle, hard landing, fast landing and hard braking, but at this
point, we do know that it would be smart to include the nose gear in your
inspection routine. This will involve you removing the fork and checking the
spindle shaft. If it is not straight, it probably should be suspect and
appropriate action taken.
Several people have designed new spindles, my self included. One is posted
on the Yahoo group site pictures. I have been flying my Pulsar since 1996,
1400 hours, with no sign of a problem, but I have decided to replace the
spindle with my own design I am having made out of one inch 4130 heat
treated to 150KSI. I am doing this because the fatigue failures I have seen have
happened up inside the collar where you cannot see, so the only detection
is if the spindle is bent. I know, over the years I have flown my aircraft I
have unintentionally bounced the nose so I decided to replace it now
rather than risk the aircraft. For me, I hate cutting up a part that has served
me so well for so many years, but I do not want to look back and say I
suspected this might happen.
Now I know you tail dragger fans out there will have a field day with
this, and that is OK, but please do take this note seriously. I do not want to
read about anyone getting hurt because of a failure. These are experimental
aircraft, and in the Pulsar case, totally without factory support, so it
is up to the owner to decide what they should do. In most cases, you are the
manufacture of the aircraft. I am taking a conservative approach and
rebuilding mine in such a way that it is easily inspected and will be stronger
than the original design.
Be safe.
Greg
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