ROSS-BS and an apology
Posted: Fri Feb 17, 2012 9:21 pm
On my 1.85:1reduction what if I said I could fix the problem for less than
$10 andno modifications to the gearbox? Let's look at what we have, a input
shaft that is limited in movementtowards the engine by the bell house or
flywheel bearing. The gear rubsthe house which results in wear - not good.
Furthermore, the naturalhelix of the gears tends to pull the input shaft to
the bell housing -even less good - although there apparently have been few
reportedproblems. If the bell housing doesn't control the thrust the thrust
isthen controlled by the crankshaft. There needs to be a "spacer" in
theresomeplace that transfers the load to the bell housing. In the case of
my1.85:1 planetary there is a counterbore in the cage that is about 0.36"deep
as measured from the face of the gage to the face of the planetarygears. The
cage c-bore has an I.D. of about 2.6", a tad less around thethrust washers at
each planetary gear. The input shaft has an O.D. of1.750". The boss on the
bell housing has a height of 0.17". Looks likewe need something that is about
0.19" thick to make up the difference.Let's dig out the bearing book. You all
have 'em don't you, how can you"engineer" without them? Let's see, Torrington
Thrust Needle Roller andCage Assemblies, page 436 of the Service Catalog
bearing numberNTA-2840, I.D.(d): 1.750 nominal, O.D.(d1): 2.500 nominal,
thickness:0.190" if we use two 0.063 thick thrust washers (part number
TRB-2840).Hmmm, it drops into place with a little thrust to spare. One
washer isagainst the bell housing boss, the other washer is against the
inputshaft gear. Great if it's an ideal world - which it isn't, better useone
0.063 thick washer and 0.032 thick washer, this will allow for alittle
thrust. Put the 0.063 washer against the bell housing boss andthe 0.032 thick
washer against the input shaft gear. The thrust bearingwill be oiled by the
existing oil in the gearbox. Problem solved.Costs: NTA-2840 bearing
$1.88 eachTRB-2840 washers (0.063 & 0.032) 4.06 (2.03 each)Source:
Motion Industries - check your yellow pagesHeck, that's less than $6, a tad
over with taxes and such.Please note:1. This applies to the 1.85:1 reduction
units, your results may vary2. Not tested - yet, but you can be sure it will
be before I fly it3. No guarantees, warranties, implied responsibilities, no
nothin', yousgets whats yous pays for.
This is a response to the same statements as below.
Actually This is very OLD news like from Feb. And a very OLD topic. That
shouldn't even be on this list. But for somebody trying to save faith in
their derogatory remark.
I can't say this redrive or any redrive is better than any other. I can say
that out of the hundreds of Ross drives out there with the thousands of
accumulated hours on them they can't be that bad of a unit. I've looked at
all the NTSB reports I care to look at and have found NONE that say anything
about any redrive failure being the cause of an accident. My deapest apologys
for dragging this out on this list. Now I going out and take my factory
rated 130 hp Derated to 85 hp and run it up to tempature so every thing gets
some fresh oil.
Ron, sorry to hear about your problems, but it is consistent with other Ross
drives. I knew I had similar problems early on when I saw the exit oil temp
coming from the gbox above 300 degF. Several of us installed additional
lubrication directly on the sun gear, plus added larger return lines and a
scavenge pump. Oil temps now are now normal. Dave Atkins had a similar Ross
problem and made the mods. He probably now has over 100 hrs on his Ross, and
when I last talked to him, it looked good inside.
Chuck
-----Original Message-----
From: ronald GOWAN [mailto:rongowan@yahoo.com]
Sent: Tuesday, October 30, 2001 3:39 PM
To: flyrotary@olsusa.com
Subject: RE: Marcotte group buy
metallic black paint. I found that the aluminum gear
set was oscillating. Chris Ross admitted "poor
workmanship". After 190 hours total time I rotated
the prop by hand and it felt like I had sand in the
gearbox. The gear set was cracked and a tooth on one
of the gears broke off. That was do to "poor
workmanship". I must be getting older because I
finally realize that flying already has its risks and
why take any more. My Long EZ is sitting in the
corner of my hangar waiting for a PSRU I can trust.
Meanwhile I am flying an O-200 Vari Eze and working on
an O-320 Long EZ. Ron
--- "Harbert, Chuck" <charles.harbert@fmglobal.com>
wrote:
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$10 andno modifications to the gearbox? Let's look at what we have, a input
shaft that is limited in movementtowards the engine by the bell house or
flywheel bearing. The gear rubsthe house which results in wear - not good.
Furthermore, the naturalhelix of the gears tends to pull the input shaft to
the bell housing -even less good - although there apparently have been few
reportedproblems. If the bell housing doesn't control the thrust the thrust
isthen controlled by the crankshaft. There needs to be a "spacer" in
theresomeplace that transfers the load to the bell housing. In the case of
my1.85:1 planetary there is a counterbore in the cage that is about 0.36"deep
as measured from the face of the gage to the face of the planetarygears. The
cage c-bore has an I.D. of about 2.6", a tad less around thethrust washers at
each planetary gear. The input shaft has an O.D. of1.750". The boss on the
bell housing has a height of 0.17". Looks likewe need something that is about
0.19" thick to make up the difference.Let's dig out the bearing book. You all
have 'em don't you, how can you"engineer" without them? Let's see, Torrington
Thrust Needle Roller andCage Assemblies, page 436 of the Service Catalog
bearing numberNTA-2840, I.D.(d): 1.750 nominal, O.D.(d1): 2.500 nominal,
thickness:0.190" if we use two 0.063 thick thrust washers (part number
TRB-2840).Hmmm, it drops into place with a little thrust to spare. One
washer isagainst the bell housing boss, the other washer is against the
inputshaft gear. Great if it's an ideal world - which it isn't, better useone
0.063 thick washer and 0.032 thick washer, this will allow for alittle
thrust. Put the 0.063 washer against the bell housing boss andthe 0.032 thick
washer against the input shaft gear. The thrust bearingwill be oiled by the
existing oil in the gearbox. Problem solved.Costs: NTA-2840 bearing
$1.88 eachTRB-2840 washers (0.063 & 0.032) 4.06 (2.03 each)Source:
Motion Industries - check your yellow pagesHeck, that's less than $6, a tad
over with taxes and such.Please note:1. This applies to the 1.85:1 reduction
units, your results may vary2. Not tested - yet, but you can be sure it will
be before I fly it3. No guarantees, warranties, implied responsibilities, no
nothin', yousgets whats yous pays for.
This is a response to the same statements as below.
Actually This is very OLD news like from Feb. And a very OLD topic. That
shouldn't even be on this list. But for somebody trying to save faith in
their derogatory remark.
I can't say this redrive or any redrive is better than any other. I can say
that out of the hundreds of Ross drives out there with the thousands of
accumulated hours on them they can't be that bad of a unit. I've looked at
all the NTSB reports I care to look at and have found NONE that say anything
about any redrive failure being the cause of an accident. My deapest apologys
for dragging this out on this list. Now I going out and take my factory
rated 130 hp Derated to 85 hp and run it up to tempature so every thing gets
some fresh oil.
Ron, sorry to hear about your problems, but it is consistent with other Ross
drives. I knew I had similar problems early on when I saw the exit oil temp
coming from the gbox above 300 degF. Several of us installed additional
lubrication directly on the sun gear, plus added larger return lines and a
scavenge pump. Oil temps now are now normal. Dave Atkins had a similar Ross
problem and made the mods. He probably now has over 100 hrs on his Ross, and
when I last talked to him, it looked good inside.
Chuck
-----Original Message-----
From: ronald GOWAN [mailto:rongowan@yahoo.com]
Sent: Tuesday, October 30, 2001 3:39 PM
To: flyrotary@olsusa.com
Subject: RE: Marcotte group buy
Chuck, after 70 hours I drained my oil it looked like^ >> ^ >>>> FlyRotary <<<< ^ << ^ <<<
! >> ! >>>>>>>>>><<<<<<<<< ! << ! <<<
metallic black paint. I found that the aluminum gear
set was oscillating. Chris Ross admitted "poor
workmanship". After 190 hours total time I rotated
the prop by hand and it felt like I had sand in the
gearbox. The gear set was cracked and a tooth on one
of the gears broke off. That was do to "poor
workmanship". I must be getting older because I
finally realize that flying already has its risks and
why take any more. My Long EZ is sitting in the
corner of my hangar waiting for a PSRU I can trust.
Meanwhile I am flying an O-200 Vari Eze and working on
an O-320 Long EZ. Ron
--- "Harbert, Chuck" <charles.harbert@fmglobal.com>
wrote:
Ron, how did your Ross fail twice? A lot of us had
our 2.17 Ross' modified
by adding a thrust bearing and added lubrication to
the gears. Did you do
either of these? Thx for the info.
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