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Michel
Joined: 10 Jan 2006
Posts: 966
Location: Norway
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 Posted: Mon May 08, 2006 12:24 am Post subject: SV: Tundra tyres. |
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Hello Kurt and Rex,
| Quote: | From: kurt schrader [smokey_bear_40220(at)yahoo.com]
Is there only one such spot per tire?
|
No, there are about 3 or 4 on each tyre, some more visible than others. I don't pivot the plane with the tyres right above the rail, of course. But, as it passes the rail, the plane is not moving straight, which could explain why the the depressions are sligthly diagonals. No, Kurt, no thump when taxiing, it's a smooth ride. The tyres are inflated to 11 psi.
I have never had that before. Those are new tyres from last summer. The depressions only came this winter. No more are coming now that the temperature is higher. In my opinion, there can be only two reasons:
1) The rail, as I suspect it most. But then, why didn't it happen with the old tyres I had the two last winters? They were of the same make, only that those new ones are not tubless, as the old ones.
2) The skis. It could be that, when I land with the penetration skis, the tyres expand so much that it locks itself on the edge of the skis. But then, I should see wear on the skis, which I don't. And I should probably feel it when landing, like, nose down, because it would work as brakes, which I didn't experienced, thanks god!
Here an interesting note about the wheel penetration skis: It makes landing a taildragger much easier because the tiny wheels at the end of the skis touch the ground first. Since they are behind the CoG it induced a slight nose down moment. Which is just the opposite of a two wheels landing which induces a nose up moment, increases AoA, bounce, and ... you know. Of course, the skis are mounted with bungees, in the front and the aft end effect is only very light because the bungees give easily way to a nose up attitude but ... it helps!
Last: Sorry guys if I write "tyres" and not "tires." It is not that I am a British snob, it is simply that I have to put my speller to US or British English, and ... I choose the latter because .... er, hum .... UK is closer to Norway, than the US! 
Cheers,
Michel
| Quote: |
Do you spin it directly on the rail without rolling
movement for each tire in turn sometime during your
parking? Or is only one tire turned on the rail?
Does it thump while taxiing, or is it no problem other
than the wear look?
As Rex says, mark the flat spots somehow and see when
you get a new one. Maybe the cause can be narrowed
down from that.
To me, it looks like the spots are larger toward the
outside of the tire. I can't see a way for this place
to be on the bottom with your bungy mounts so close to
the belly even with the plane's weight on the gear.
They can't pull up and bring the gear in much more in
flight to cause that spot on touchdown, or can they?
You need to lift it off the gear to see if those
outside spots are straight down in flight. Make sure
your wheels spin freely then as well. If these spots
are at the bottom in flight, it must have to do with
landing and not action after the gear spreads???
More data needed....
Kurt S.
--- Rex <gypsybee(at)copper.net> wrote:
> Michel,
> I wonder if the construction of ATV tires (tyres)
> differs enough that
> they may more easily form these flat spots when
> stored in cold for a
> while. The fact that the tire is not as thick as was
> designed for normal
> useage (due to the treads removed), may contribute
> to the problem. Is
> this a recent development? You've probably already
> thought of this;
> perhaps you could mark the tires or note the
> depression in relation to
> tire lettering. Then see if it later occurs in
> another location on the
> tire. That would indicate an extrernal cause (the
> rail) verses a defect
> in the tire.
> Please keep us informed as I and others have these
> kind of tires.
> Rex
> Florida.
>
>
> Michel Verheughe wrote:
> >On May 7, 2006, at 6:38 PM, kurt schrader wrote:
> >
> >>Hummm. Some tires still show a seam where the
> belt wrap joins.
> >>
> >This is not the case, Kurt. Please look at these
> photos I took today:
> >
> >http://home.online.no/~michel/tmp/Tyres.jpg
> >
> >On the two upper photos, you can see, in the red
> circle, the
> >depressions in the tyres. On the lower photo, the
> steel rail that may
> >be the cause of the depressions. It's the only
> thing I can think of.
> >Strange, isn't it? Also note that the hangar
> (actually an old workshop
> >for the airfield) is not wide enough to get my
> Kitfox in and out
> >straight. When over the rail, I have to turn the
> plane 180 degrees to
> >get one wing out at the time.
> >
> >Cheers,
> >Michel
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Rex Hefferan
Joined: 10 Jan 2006
Posts: 147
Location: Olney Springs, Colorado USA "NOT a Kitpig"
|
| Posted: Mon May 08, 2006 8:00 am Post subject: SV: Tundra tyres. |
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|
Well, manufacturers can change something in a product at any time which
could result in a difference between sets of tires, not to mention a
difference verses tubeless style tires.
Rex
No problem about British spellings from me. Not to start another
off topic, but I often wonder how certain American English spellings and
pronunciations were influenced for specific words. Like "Organize" where
we use a z instead of an s. Certain pronunciations like "Schedule". I
think I could guess most reasons in a general way, but the entomology is
interesting. Thanks Kurt for the BR explanation.
Do not archive
Michel Verheughe wrote:
| Quote: |
Hello Kurt and Rex,
>From: kurt schrader [smokey_bear_40220(at)yahoo.com]
>Is there only one such spot per tire?
>
>
No, there are about 3 or 4 on each tyre, some more visible than others. I don't pivot the plane with the tyres right above the rail, of course. But, as it passes the rail, the plane is not moving straight, which could explain why the the depressions are sligthly diagonals. No, Kurt, no thump when taxiing, it's a smooth ride. The tyres are inflated to 11 psi.
I have never had that before. Those are new tyres from last summer. The depressions only came this winter. No more are coming now that the temperature is higher. In my opinion, there can be only two reasons:
1) The rail, as I suspect it most. But then, why didn't it happen with the old tyres I had the two last winters? They were of the same make, only that those new ones are not tubless, as the old ones.
2) The skis. It could be that, when I land with the penetration skis, the tyres expand so much that it locks itself on the edge of the skis. But then, I should see wear on the skis, which I don't. And I should probably feel it when landing, like, nose down, because it would work as brakes, which I didn't experienced, thanks god!
Here an interesting note about the wheel penetration skis: It makes landing a taildragger much easier because the tiny wheels at the end of the skis touch the ground first. Since they are behind the CoG it induced a slight nose down moment. Which is just the opposite of a two wheels landing which induces a nose up moment, increases AoA, bounce, and ... you know. Of course, the skis are mounted with bungees, in the front and the aft end effect is only very light because the bungees give easily way to a nose up attitude but ... it helps!
Last: Sorry guys if I write "tyres" and not "tires." It is not that I am a British snob, it is simply that I have to put my speller to US or British English, and ... I choose the latter because .... er, hum .... UK is closer to Norway, than the US!
Cheers,
Michel
>Do you spin it directly on the rail without rolling
>movement for each tire in turn sometime during your
>parking? Or is only one tire turned on the rail?
>
>Does it thump while taxiing, or is it no problem other
>than the wear look?
>
>As Rex says, mark the flat spots somehow and see when
>you get a new one. Maybe the cause can be narrowed
>down from that.
>
>To me, it looks like the spots are larger toward the
>outside of the tire. I can't see a way for this place
>to be on the bottom with your bungy mounts so close to
>the belly even with the plane's weight on the gear.
>They can't pull up and bring the gear in much more in
>flight to cause that spot on touchdown, or can they?
>You need to lift it off the gear to see if those
>outside spots are straight down in flight. Make sure
>your wheels spin freely then as well. If these spots
>are at the bottom in flight, it must have to do with
>landing and not action after the gear spreads???
>
>More data needed....
>
>Kurt S.
>
>--- Rex <gypsybee(at)copper.net> wrote:
>
>
>
>>Michel,
>> I wonder if the construction of ATV tires (tyres)
>>differs enough that
>>they may more easily form these flat spots when
>>stored in cold for a
>>while. The fact that the tire is not as thick as was
>>designed for normal
>>useage (due to the treads removed), may contribute
>>to the problem. Is
>>this a recent development? You've probably already
>>thought of this;
>>perhaps you could mark the tires or note the
>>depression in relation to
>>tire lettering. Then see if it later occurs in
>>another location on the
>>tire. That would indicate an extrernal cause (the
>>rail) verses a defect
>>in the tire.
>> Please keep us informed as I and others have these
>>kind of tires.
>>Rex
>>Florida.
>>
>>
>>Michel Verheughe wrote:
>>
>>
>>>On May 7, 2006, at 6:38 PM, kurt schrader wrote:
>>>
>>>
>>>
>>>>Hummm. Some tires still show a seam where the
>>>>
>>>>
>>belt wrap joins.
>>
>>
>>>>
>>>>
>>>>
>>>This is not the case, Kurt. Please look at these
>>>
>>>
>>photos I took today:
>>
>>
>>>http://home.online.no/~michel/tmp/Tyres.jpg
>>>
>>>On the two upper photos, you can see, in the red
>>>
>>>
>>circle, the
>>
>>
>>>depressions in the tyres. On the lower photo, the
>>>
>>>
>>steel rail that may
>>
>>
>>>be the cause of the depressions. It's the only
>>>
>>>
>>thing I can think of.
>>
>>
>>>Strange, isn't it? Also note that the hangar
>>>
>>>
>>(actually an old workshop
>>
>>
>>>for the airfield) is not wide enough to get my
>>>
>>>
>>Kitfox in and out
>>
>>
>>>straight. When over the rail, I have to turn the
>>>
>>>
>>plane 180 degrees to
>>
>>
>>>get one wing out at the time.
>>>
>>>Cheers,
>>>Michel
>>>
>>>
>__________________________________________________
>
>
>
>
>
>
|
--
Karla and Rex Hefferan
Gypsy Bee Innkeepers
719-651-5198 or 719-651-9192
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_________________
Rex
N740GP - M2/582
Colorado |
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smokey_bear_40220(at)yaho
Guest
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| Posted: Mon May 08, 2006 9:49 am Post subject: SV: Tundra tyres. |
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|
Michel,
I really can't see the rail doing that if the tire is
allowed to rotate as you turn the plane. Even doing a
no tire rotation turn with your plane might scrub the
tire, but not make a flat spot. The rubber would have
to be very soft to scrub it flat in that way.
Cold weather seems to be the clue here.
Do the flat spots disappear and leave just scrub marks
when the tire gets warm?
Is it possible that you have ice buildup between the
tire and the ski and it scrubs the tire and rips the
ice off on landing without touching the ski? It could
ice up on the side as well as on the tread.
Remember the ski acts like a carpenter's plane if it
touches the tire. You could be shaving the tire
against the ski without seeing harm on the ski. Make
sure to round those edges off and maybe open the gap
up 2 mm more.
Those are either flat spots from cold tires holding
shape, too soft rubber, or a significant scrubbing
that doesn't occur every time. Otherwise you would
have a flat spot for every flight/parking event.
You need to look closely at those marks and see if
there are any little cuts only in them. Straight
cuts? Rotational cuts? No little cuts? BS cuts from
ahhhh Barely Skiing?
Kurt S.
--- Michel Verheughe <michel(at)online.no> wrote:
| Quote: | Hello Kurt and Rex,
> From: kurt schrader [smokey_bear_40220(at)yahoo.com]
> Is there only one such spot per tire?
No, there are about 3 or 4 on each tyre, some more
visible than others. I don't pivot the plane with
the tyres right above the rail, of course. But, as
it passes the rail, the plane is not moving
straight, which could explain why the the
depressions are sligthly diagonals. No, Kurt, no
thump when taxiing, it's a smooth ride. The tyres
are inflated to 11 psi.
I have never had that before. Those are new tyres
from last summer. The depressions only came this
winter. No more are coming now that the temperature
is higher. In my opinion, there can be only two
reasons:
|
__________________________________________________
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Rex Hefferan
Joined: 10 Jan 2006
Posts: 147
Location: Olney Springs, Colorado USA "NOT a Kitpig"
|
| Posted: Mon May 08, 2006 10:37 am Post subject: SV: Tundra tyres. |
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|
Kurt is right, the tire needs to be looked at very closely for evidence
of what may be the cause. My suggestion was only regarding a cold
temperature cause. I would probably remove a tire and inspect it inside
also.
Rex
Florida (where Kurt and I are unlikely to see cold enough temps for this
problem, but my Kitfox is in Colorado)
kurt schrader wrote:
| Quote: |
Michel,
I really can't see the rail doing that if the tire is
allowed to rotate as you turn the plane. Even doing a
no tire rotation turn with your plane might scrub the
tire, but not make a flat spot. The rubber would have
to be very soft to scrub it flat in that way.
Cold weather seems to be the clue here.
Do the flat spots disappear and leave just scrub marks
when the tire gets warm?
Is it possible that you have ice buildup between the
tire and the ski and it scrubs the tire and rips the
ice off on landing without touching the ski? It could
ice up on the side as well as on the tread.
Remember the ski acts like a carpenter's plane if it
touches the tire. You could be shaving the tire
against the ski without seeing harm on the ski. Make
sure to round those edges off and maybe open the gap
up 2 mm more.
Those are either flat spots from cold tires holding
shape, too soft rubber, or a significant scrubbing
that doesn't occur every time. Otherwise you would
have a flat spot for every flight/parking event.
You need to look closely at those marks and see if
there are any little cuts only in them. Straight
cuts? Rotational cuts? No little cuts? BS cuts from
ahhhh Barely Skiing?
Kurt S.
|
| | - The Matronics Kitfox-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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_________________
Rex
N740GP - M2/582
Colorado |
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Michel
Joined: 10 Jan 2006
Posts: 966
Location: Norway
|
| Posted: Tue May 09, 2006 12:52 am Post subject: SV: Tundra tyres. |
|
|
From: kurt schrader [smokey_bear_40220(at)yahoo.com]
| Quote: | Have you seen any crop circles lately? 
|
Yes, concentric circles about the size of the distance between the main gears of a B-767 and your name was all over it! The Norwegian authorities are being informed!
| Quote: | I had a tire on my van where the tread looked fine, but seperated internally and
got a big flat spot.
|
That could have happened to me too. I'll need to look at it. But, Ron and Kurt, here a good analogy: If you press hard with your thumb on the fabric of your wing, you'll make a hollow that will come back to normal after a time and/or with the help of heat.
Well, my tyres are exactly the same, except that they don't seem to come back to the normal smooth and round shape. Since there is nothing visible on the outside, maybe there is something damaged on the inside. But I can't imagine what, when I look at the inside of the old tyres. What do you think?
Cheers,
Michel
| | - The Matronics Kitfox-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Kitfox-List |
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_________________
Kitfox 3 - Jabiru 2200 |
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smokey_bear_40220(at)yaho
Guest
|
| Posted: Tue May 09, 2006 2:25 pm Post subject: SV: Tundra tyres. |
|
|
Michel,
I think the folded innertube problem is much like my
tread seperation problem. Good suggestion. It could
be that simple. 11 psi isn't much and the cold
operations might be enough to spin the tires a little
and roll up the innertube? Or pinched just from
assembly?
One thing to try is to blow them up to the max
pressure for a bit, especially if it is warm that day.
Taxi around and see if things stretch out.
If not, do as was suggested and take a wheel apart and
see if the innertube is creased. Put it back together
with the powder so it can slip in place.
Just an idea.
Now I've got to go clean the wheat out of my 767
tires...
Kurt S.
--- Michel Verheughe <michel(at)online.no> wrote:
| Quote: | From: kurt schrader [smokey_bear_40220(at)yahoo.com]
> Have you seen any crop circles lately?
Yes, concentric circles about the size of the
distance between the main gears of a B-767 and your
name was all over it! The Norwegian authorities are
being informed!
> I had a tire on my van where the tread looked
fine, but seperated internally and
> got a big flat spot.
That could have happened to me too. I'll need to
look at it. But, Ron and Kurt, here a good analogy:
If you press hard with your thumb on the fabric of
your wing, you'll make a hollow that will come back
to normal after a time and/or with the help of heat.
Well, my tyres are exactly the same, except that
they don't seem to come back to the normal smooth
and round shape. Since there is nothing visible on
the outside, maybe there is something damaged on the
inside. But I can't imagine what, when I look at the
inside of the old tyres. What do you think?
Cheers,
Michel
|
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