[LNC2] MLG tires hitting upper wing skin

Submitted by Anonymous on

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From: John Cooper <snopercod [at] comporium.net>
Sender: <marv [at] lancaironline.net>
Subject: [LNC2] MLG tires hitting upper wing skin
Date: Sat, 07 Jun 2014 11:15:54 -0400
To: <lml [at] lancaironline.net>

After replacing the original Rosenhan brake calipers that came with my L-235 with new Matco B5-4 units, the tire now contacts the underside of the upper wing skin just before the gear is fully retracted. As you all know, the brake mounting plates fit between the aluminum gear casting and the axle. The old Rosenhan die-cast brake plates were .210 thick. The new Matco brake plates are only .125 thick, so I had to add shims between the casting and axle to keep the brake disc properly "centered" between the brake pads. On my latest installation, the distance between the gear casting and the axle is now .310, which extends the wheel and tire out  .100 more than before. The gear door is probably only .060 away from closing when the tire hits the underside of the upper wing skin, so the addition of the shims seems to have caused the problem.



I originally had 70 PSI in my Cheng Shen MLG tires and bled them down to 60 PSI but that didn't help.



Today I will attempt to reduce the thickness of the shims, but I fear that's not going to work because the new Matco brake pads are thicker than the old Rosenhan pads and need more clearance to allow for wear.



So the only options I can think of at this point would be to 1. carve out a crescent of the upper wing skin core where the tire it hitting, 2. grind down the ridge on the tire where the tread meets the sidewall, 3. Reform the middle gear door, or 4. fly with the aft edge of the middle gear door about 1/16" away from being flush.



Has anyone run into this problem? Any suggestions?

[LNC2] MLG tires hitting upper wing skin

Submitted by Anonymous on

From: <Sky2high [at] aol.com>
Subject: Re: [LML] [LNC2] MLG tires hitting upper wing skin
Date: Sat, 7 Jun 2014 11:22:24 -0400 (EDT)
To: <lml [at] lancaironline.net>
Message Header


Undecoded Message

The trailing edge of the middle gear door can
be slightly adjusted by carefully bending the bracket to which it is
attached.
 
Grayhawk 
 
In a message dated 6/7/2014 10:16:01 A.M. Central Daylight Time,
snopercod [at] comporium.net writes:

After
replacing the original Rosenhan brake calipers that came with my
L-235
with new Matco B5-4 units, the tire now contacts the underside of
the
upper wing skin just before the gear is fully retracted. As you all
know,
the brake mounting plates fit between the aluminum gear casting
and the
axle. The old Rosenhan die-cast brake plates were .210 thick.
The new
Matco brake plates are only .125 thick, so I had to add shims
between the
casting and axle to keep the brake disc properly "centered"
between the
brake pads. On my latest installation, the distance between
the gear
casting and the axle is now .310, which extends the wheel and
tire
out  .100 more than before. The gear door is probably only .060
away
from closing when the tire hits the underside of the upper wing
skin, so
the addition of the shims seems to have caused the problem.

I
originally had 70 PSI in my Cheng Shen MLG tires and bled them down to
60
PSI but that didn't help.

Today I will attempt to reduce the thickness
of the shims, but I fear
that's not going to work because the new Matco
brake pads are thicker
than the old Rosenhan pads and need more clearance
to allow for wear.

So the only options I can think of at this point
would be to 1. carve
out a crescent of the upper wing skin core where the
tire it hitting, 2.
grind down the ridge on the tire where the tread meets
the sidewall, 3.
Reform the middle gear door, or 4. fly with the aft edge
of the middle
gear door about 1/16" away from being flush.

Has
anyone run into this problem? Any suggestions?


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[LNC2] MLG tires hitting upper wing skin

Submitted by Anonymous on

From: Bill Harrelson <n5zq [at] verizon.net>
Sender: <marv [at] lancaironline.net>
Subject: Re: [LML] [LNC2] MLG tires hitting upper wing skin
Date: Sat, 07 Jun 2014 12:17:31 -0400
To: <lml [at] lancaironline.net>
Message Header


Undecoded Message

John,



If you go with option 1, be sure to add a 2 bid over the "carve out". I would recommend carbon as it is thinner than fiberglass.



If you go with option 4, you might loose 1/4 knot cruise speed.



Bill Harrelson

N6ZQ  IV 550 hrs









-----Original Message----- From: John Cooper



So the only options I can think of at this point would be to 1. carve

out a crescent of the upper wing skin core where the tire it hitting, 2.

grind down the ridge on the tire where the tread meets the sidewall, 3.

Reform the middle gear door, or 4. fly with the aft edge of the middle

gear door about 1/16" away from being flush.

[LNC2] MLG tires hitting upper wing skin

Submitted by Anonymous on

From: Chris Zavatson <chris_zavatson [at] yahoo.com>
Sender: <marv [at] lancaironline.net>
Subject: Re: [LML] [LNC2] MLG tires hitting upper wing skin
Date: Sat, 07 Jun 2014 12:17:43 -0400
To: <lml [at] lancaironline.net>
Message Header


Undecoded Message
John,
The factory 360 had some core material removed from the upper wing skin for tire clearance.  The wouldn't be my first choice though.  Can you remove any core material from the door to tuck it in closer to the gear? 

Chris Zavatson
N91CZ
360std


On Saturday, June 7, 2014 8:16 AM, John Cooper <snopercod [at] comporium.net> wrote:




After replacing the original Rosenhan brake calipers that came with my
L-235 with new Matco B5-4 units, the tire now contacts the underside of
the upper wing skin just before the gear is fully retracted. As you all
know, the brake mounting plates fit between the aluminum gear casting
and the axle. The old Rosenhan die-cast brake plates were .210 thick.
The new Matco brake plates are only .125 thick, so I had to add shims
between the casting and axle to keep the brake disc properly "centered"
between the brake pads. On my latest installation, the distance between
the gear casting and the axle is now .310, which extends the wheel and
tire out  .100 more than before. The gear door is probably only .060
away from closing when the tire hits the underside of the upper wing
skin, so the addition of the shims seems to have caused the problem.

I
originally had 70 PSI in my Cheng Shen MLG tires and bled them down to
60 PSI but that didn't help.

Today I will attempt to reduce the thickness of the shims, but I fear
that's not going to work because the new Matco brake pads are thicker
than the old Rosenhan pads and need more clearance to allow for wear.

So the only options I can think of at this point would be to 1. carve
out a crescent of the upper wing skin core where the tire it hitting, 2.
grind down the ridge on the tire where the tread meets the sidewall, 3.
Reform the middle gear door, or 4. fly with the aft edge of the middle
gear door about 1/16" away from being flush.

Has anyone run into this problem? Any suggestions?


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[LNC2] MLG tires hitting upper wing skin

Submitted by Anonymous on

From: <marv [at] lancair.net>
Subject: Re: [LML] [LNC2] MLG tires hitting upper wing skin
Date: Mon, 09 Jun 2014 07:45:23 -0400
To: <lml>
Message Header


Undecoded Message



Posted for "William Rumburg"
<lancair403 [at] verizon.net>:

> John -
>
> There's an easier and more elegant solution:
>
> The Lancair-supplied
middle gear door attach bracket is unnecessary. I never
>installed mine because the bottom of the door can just as well be attached

>directly to the casting and you'll gain at least 1/8" closure in the process.
>You can check this in advance for your own situation,
however, by removing
>the door and attach bracket. Retract the gear and hold the door in place to
>verify that it then fully closes; if
it does, proceed as follows -
>
> 1) Drill and tap the casting for 1/4" holes near the bottom of the door,
>about 2 or 2-1/2"
apart (see photo 1644)
>
> 2) Install short 1/4" studs in the holes. Retract the gear and, holding the
>door in the exact desired
position, press it into the studs to mark the
>location to drill for new holes in the door itself.
>
> 2) Create a local
hard-point in the door at the attach screw area by using a
>1-1/2" piloted hole saw to remove the inner skin and foam core (Do Not remove

>the outer skin). Prep and fill the circular area with a thick resin/flox
>paste (you'll also have to fill the holes previously used for
the attach
>bracket)
>
> 4) Retract the gear and hold the door in the exact desired position, again
>letting the studs
again mark the hole position. Drill for the new 1/4" attach
>screws and tinnerman washers - the aft end will require a couple of washers

>between the door and casting and that will allow for some adjustment of the
>door against the fuselage. Use nylon washers against the
door at all
>locations (see photo 1643)
>
> My middle gear door installation is "solid as a rock"
>
> Bill
Rumburg
> N403WR  (Sonic bOOm)
>
> ----- Original Message ----- From: "John Cooper"
<snopercod [at] comporium.net>
> To: "Lancair Mailing List" <lml [at] lancaironline.net>
> Sent: Saturday, June 07, 2014 11:15
AM
> Subject: [LML] [LNC2] MLG tires hitting upper wing skin
>
>
>> After replacing the original Rosenhan brake calipers
that came with my L-235
>>with new Matco B5-4 units, the tire now contacts the underside of the upper
>>wing skin just before the
gear is fully retracted. As you all know, the brake
>>mounting plates fit between the aluminum gear casting and the axle. The old

>>Rosenhan die-cast brake plates were .210 thick. The new Matco brake plates
>>are only .125 thick, so I had to add shims between
the casting and axle to
>>keep the brake disc properly "centered" between the brake pads. On my latest
>>installation, the
distance between the gear casting and the axle is now .310,
>>which extends the wheel and tire out .100 more than before. The gear door is

>>probably only .060 away from closing when the tire hits the underside of the
>>upper wing skin, so the addition of the shims
seems to have caused the
>>problem.
>>
>> I originally had 70 PSI in my Cheng Shen MLG tires and bled them down to 60

>>PSI but that didn't help.
>>
>> Today I will attempt to reduce the thickness of the shims, but I fear that's

>>not going to work because the new Matco brake pads are thicker than the old
>>Rosenhan pads and need more clearance to allow for
wear.
>>
>> So the only options I can think of at this point would be to 1. carve out a
>>crescent of the upper wing skin
core where the tire it hitting, 2. grind down
>>the ridge on the tire where the tread meets the sidewall, 3. Reform the
>>middle
gear door, or 4. fly with the aft edge of the middle gear door about
>>1/16" away from being flush.
>>
>> Has anyone run
into this problem? Any suggestions?
>>
>>
>> --
>> For archives and unsub
http://mail.lancaironline.net:81/lists/lml/List.html