Any progress on the simple PSRU? I have a neighbor that is a
retired millwright, and he has a 12" metal lathe in his basement.
He has been building mini steam engines in his basement for a
while- a steam powered mini ferris wheel, locomotive, etc.
Last I remember you were discussing using the ceramic bearings-
and were trying to get them from China. If I can get an idea of
the internal parts and where to get them, I can try to make one.
Have we made any progress lately?
Kevin Alderman
It will be awhile. We had a ceramic bearing supplier picked out
but there was some evidence he was less than reliable. We are
attempting to finding another source.
Paul Lamar
I assume the heart is a Ford planetary, but where does the splined
shaft come from? Do we have to machine the splines on a shaft?
Kevin Alderman
It must be welded up from a manual transmission, one inch
diameter, input shaft or Ford auto tranny splined part. Tracy
uses the auto tranny part.
Paul Lamar
OK, I guess I need to go get a used E4OD and tear it apart and see
what's inside. Sounds like fun!
Kevin Alderman
No need. New parts are cheap.
http://www.makcotransmissionparts.com/
I have ordered from them and I think Tracy also buys from them.
Here is an outfit on the west coast.
http://www.slauson.com/
We are in the process of ordering the bearings in china now.
The smart thing to do is let us build one and see if it works
first :)
Paul Lamar
\--------------------------------------------------
You can order thin section steel bearings from mcmaster carr
but steel thin section bearings are limited rpm wise.
we are using the 4 inch size.
This is why we are trying to buy ceramic thin section bearings.
Cost is the reason for buying them in china.
Paul Lamar
cheaper
I just noticed the NOTE:. The max RPM is with grease as a
lubricant. High RPM would heat the grease due to the internal
friction in the viscous material. How will lubricating with oil
affect the RPM rating?
Dale Davies
Perhaps a bit higher but no way is steel going to live long enough
with grease or oil.
Here is the specs on Shanghi Lilly thin section ceramic bearings.
The success of this design depends on the high rpm capability of
ceramic
bearings.
Paul Lamar
Paul, I was looking at the attachments and it appears that the 4"
standard all stainless construction thin section bearing is rated
at 4800 RPM (grease) and 5700 RPM (oil). The propshaft would be
turning 7500 RPM/ 2,85 or 2631 RPM, well in range of a 5700 RPM
bearing. It would seem that using silicon nitride balls in the
bearing for an 8000 RPM rating would be overkill. I understand
that the input shaft might be turning 7500 RPM but with a much
smaller diameter where the speed ratings are much higher. It would
seem that a standard size bearing with C3 clearance would be
appropriate on the input shaft.
george grimes
The Shanghi Lilly are ceramic balls.
What manufacture was that? Most all steel thin section bearings
that size are limited to below 1000 rpm.
Paul Lamar
Paul, I was looking at the attachments on the 8:51 am posting.
One chart was 4800/5700 and the other chart ranged from 8500 to
15000 RPM for the same size. It would seem either type could be used.
george
Those RPM numbers are for the silicon nitride balls not steel
balls. The last attached jpg shows a steel ball bearing that comes
close.
The penalty is a smaller shaft and a much larger housing.
The shaft strength goes up with cube or the fourth power of the
diameter.
Paul Lamar
------------------------------------------------------------------------
This company in general does not post the RPM.
Paul Lamar
---------------------------------------------------------------------
This one might be worth a try to validate the concept as Milo has
suggested.
The cost makes it unattractive.
Paul Lamar
==========================================================================
Paul, will this do the job? Milo
Buy online VD040CP0 Thin Section Bearing 4"x5"x1/2" inch Open
Slim Ball Bearings VXB Home Thin Section Bearings
VD040CP0 Thin Section Bearing 4"x5"x1/2" inch Open Slim Ball
Bearings
Quantity in Basket: None
Part Number: Kit13153
Our Low Price: $179.00
Shipping Weight: 0.10 pounds
========================================================================
No I don't think so there is no RPM specified.
It would only last a few hours.
Paul
Years ago I was rebuilding Allison powershift transmissions for off
highway
equipment. One rebuild I noticed a new bearing to repalce one I had
used numerous times. The part number on the box was different, but
the bearing had the same numbers etched on it. I asked the manager
who was also a mechanic. He did a bunch of checking as the price was
almost double and found out there is a tolerance on bearings. The
manufacturer part number is the same as the dimensions are identical,
but the closer tolerance goes in a different box with a
corresponding cost change. Two bearings listed in previous posts;
1: RBC KD040 CPO List $389
2: VD040 CPO List $179 Question is, what would the
difference be considering the dimensions are the same? Just the
change in the first letter of the part number K or V. If normal
economics apply, the more expensive bearing would be of better quality.
Dale Davies
Without looking it up again, I believe bearings have what is call an
ABEC rating. ABEC-7 appears to be the common spec for super
precision bearings.
Ed Carver
Group,
The ABEC scale is an industry accepted standard for the tolerances
of a ball bearing. It was developed by the Annular Bearing
Engineering Committee (ABEC) of the American Bearing Manufacturers
Association (ABMA). There are five classes from largest to smallest
tolerances: 1, 3, 5, 7, and 9. The higher ABEC classes provide
better precision, efficiency,[citation needed] and greater speed
capabilities, but do not necessarily make the components spin
faster.[1] The ABEC rating does not specify many other critical
factors, such as smoothness of the rolling contact surfaces, ball
precision or quality/type of steel used.
The bearing material is not specified in the ABEC grades. Bearings
not conforming to at least ABEC 1 can not be classified as precision
bearings as their tolerances are too loose.
The scale is designed to allow a user to make an informed decision
about the type of bearing they are purchasing. High rated bearings
are intended for precision applications like aircraft instruments or
surgical equipment. Lower grades are intended for the vast majority
of applications such as vehicles, mechanical hobbies, skates,
skateboards, fishing reels and industrial machinery. High ABEC
rated bearings allow optimal performance of critical applications
requiring very high RPM and smooth operation.
http://en.wikipedia.org/wiki/ABEC
Rotor Head
Ok, so to help get my grey matter wrapped around this tid bit of
information;
the VD040 CPO bearing. Does the 4 in the 040 designate it as an ISO class
4/ABEC 7 rearing? How does the KD040 CPO bearing differ?
Dale Davies
You got me Dale.
Paul Lamar
If the same bearing is cheaper in China than the U.S. then by all
means purchase from China, If the Chinese manufactured bearing is
cheaper than the U.S. made unit (if there is such a thing) Then not
only are you risking your ass and those who may fly with you, for a
couple of hundred $, your also sacrificing U.S. jobs, hurting the U.S.
economy, and, gulp, being a cheapskate, that is why Aussie
manufacturing has passed the S bend. Blundstone work boots determined
that prior to moving manufacturing to India. At least they are a
member of the Commonwealth and friends of ours. (Except on the cricket
field, then we want to crush them, and vice versa).
A man approaches a beautiful young woman and asks " Will you sleep
with me for $1million" the woman briefly pauses and replies "Yes,
O.K.". The man then asks "Will you sleep with me for $20" The woman
vigorously replies "What kind of woman do you think I am?" the man
answers "We have already determined that, now we're just haggling over
the price ! "
Food for thought do you not think. I do not intend to offend.
Graeme Riley
I had to step in here-
1. Continental Aircraft Engines (TCM) is now a Chinese company- so by
this
logic I should consider their parts now inferior.
2. Almost all of our computer parts worldwide are made in China- so why
have our computers not stopped working?
3. Cessna makes its new 162 in China, so is it not airworthy?
4. GM has 15 plants in China and as per a statement from the President of
Government Motors "70% of our cars are now made in locations other than
in
the US". He made this statement at a Chinese event that marked GMs
opening
of a major R&D unit in China, to -his words- replace the R&D department
in
the US.
5. Hawker Beechcraft- now under bankruptcy protection- has been actively
pursuing a manufacturing relationship with the Chinese for years- the
fact
that they hadn't been able to reach an agreement is why they went under
according to a statement by their CEO. He said that "an agreement with
the
Chinese to begin manufacturing in China was mandatory if Hawker was to
survive". So, do we not fly in a Hawker anymore?
The issue of items being made in China are not always one of quality- the
Ipad is made in Taiwan, China, and about everywhere in the world except
here. Did that keep millions from buying them? Does that make them not
work?
The problem is the high taxes here and the high cost of labor here. Why
do
you think the Chinese are building the bridges in California? Cessna is
making the planes in China, GM is building cars in China, etc. etc.
Economics 101.
I have no issues with a bearing made in China, if it meets quality
standards. However, my American Made Continental blew up at 1700 hours
and
is now going off to be melted down. But for $54,000 I can buy a
replacement. And, do not forget our rotaries are not made here either. I
have 3 of them now.
Kevin Alderman
The current leftist regime controlling the U.S. and most of the rest of
the
western world can be compared to the 1960s cartoon MR. MAGOO, wherein you
have an extremely nearsighted decrepit old man being lead around by a
Chinese guy named Charlie who is continually saving Magoo's ass.
In the U.S. a mass experiment began when the American Collegiate
Ubermensch
took the sands of ontology and rearranged it all within our popular
culture
and education sys. The young Magoo's of the 60s had no idea where the
newly
rearranged elements of ontology would lead them, nor were they aware of
the
change, as a result, China has become the manufacturing source for nearly
everything. And all because of the implicit near sightedness of the
driving
philosophies of the day.
Consequently, the road to serfdom has broadened to the extent that now
~50%~ of our population is happily on the government dole, and most of
them
have no compunction about using their welfare debit card to buy ice cream
and cake.
So there ya go, China to the rescue. And give em credit, soviet
totalitarianism drove their own economy into the ground, the Chicoms on
the
other hand, looked carefully at Hong Kong and cried out in their newly
enlightened state, 'AH SO' O' great ones" then thanked the British for
renting the spot from them, and thereafter duplicated within the mainland
what had made HK so successful.
Whatayado now? In my case, I have relatives in the Filipines, Some of
whom
work in HK and are members of the vast OFW (overseas Filipino workers). I
suspect I will be making better acquaintance with the ones in HK as they
can send stuff to the U.S. cheaply.
Don't work too hard right? In my case, I'm like the guy who built the
first
Wright Bros. engine. Just get me the raw materials and we'll get the show
on the road with minimal investment.
Sadly:( I can't make bearings, so anyone who wants to add the
bearings
to the pile of materials I have for Paul's new tube shaft prop reduction
unit, and also has time to do the leg work to get the materials machined
for the assembly, I'll gladly put it all in a box and send it to you.
Any takers?
Ed Carver
I can take you up on the offer- I have a neighbor that has a metal lathe
and is a retired machinist. He makes mini steam engines as a hobby. He is
fascinated with the airplane I am building.
If I am up to speed on it, we need to find a bearing for the end and have
it machined to fit in the end of the barrel.
With any luck maybe by summers end or sooner I could have something that
will turn.
Is that about right with the status?
Kevin Alderman
Kevin and Milo--
The first thing needed is the bearings. If you can get some bearings in
hand, then the parts/materials I have can be machined to build the
assembly. You could always use bearings with steel balls to test before
getting ceramic ball version for the final assembly. Our quoted prices for
the ceramic bearings was between $33 and $500 each unit plus shipping.
I have yet to add the front rx8 eshaft seal to the batch. Also the planet
end pilot bearing for the input shaft has not been selected and there are
many options for that as it is a relatively low speed application. A
needle
bearing can be used and is probably best. The counterbalance pilot can be
anything because the input shaft does not turn inside pilot hole any more
than a few degrees either direction.
I would stick with the 6821 size because it increases the simplicity of
machine work. The shaft material size is 4.25" The bearing id is 105mm.
The
housing id is 5" The bearing od is130mm. The 6820 could be used but it
would unnecessarily reduce the size of the shaft, and necessitate using a
step down sleeve for the id of the tube housing. The same goes for the
4x5x1/2 bearing.
The 4.25 shaft size was selected because it is slightly larger than the
planet housings. Consequently, when I decided to use the shaft material as
the carrier for the planet gears, it turned out we had more than enough
material for this purpose. You need to clearly visualize what the whole
assembly will be like when finished. The integral prop shaft design cannot
allow fluids to pass into the hollow shaft so it must be machined from
each
end.
The housing flange is nearly 8.5" dia. The housing od is 6". Your
machinist
will need a steady rest for his lathe large enough to take the 6"
material.
Or his lathe will need a larger than 6" bore through the chuck which is
highly unlikely.
Hopefully you saved the rhino images Paul put up in the past describing
all
of this. We have housings welded up. One is intended to match the
dimensions of Tracy's unit with the flange set to work with the 89 rx7
auto
trans bell. The other bolts to the same bell but is 4 inches or so longer
and is intended for my cozy4. I have cut one shaft to length for my
housing. There may be enough length left on the 4.25 bar to make 3 more
shafts. But likely only two. You must decide which length you want and
what
bell housing you will use if any. I have enough housing material to make 6
units.
The benefit for this shaft design is that I can make it longer or shorter
relative to engine position and weight. I wanted to be a good 6 inches or
so further back than the stock position.
Ed Carver
Ed,
Food for thought.
When picking up our test stand at Pauls place last fall he and I had a
discussion about average life of a homebuilt airplanes and I related to him
an article that I had read some years ago that said 200 flying hours was
it.
In reference to the bearings under discussion, even if a homebuilder had to
shit can the bearings every 200 hours so be it.
For me simplicity is the name of the game, and that usually leads to safety
which is the game, to change bearing out at 200, 300, or 400 is no big
deal.
I think that trying to scratch build for 2000 hour overhauls should not be
our goal. Later after a number of units have been tested we can improve the
design, much like Tracy.
My personnel choice would be a plain bearing setup @ 3.1 : 1 for an RX 8 at
@ 230 hp, w/torq sender but will go with what ever is decided upon to get
started. But get started we must.
One thing we have not done is to settle on a specific drive setup, but we
are getting there.
For the groups information my next project is building a test stand on a
trailer in a pusher configuration dedicated to drive testing only by
jerking
the RX8 engine, wire harness, cooling system, computer, fuel tank/system
just as it is mounted in the car using all of the same components. Not
going
to make any attempt to mod the engine, just run it as is, probalbly use
part
of the car frame, seat, winshield, instruments, etc. as well. Just going to
take a torch and cut around the seat and engine/cooling plunk it on the
trailer.
My plan is to have it strictly as a running test bench. We should be able
to
easily mount that in a couple days, turn the switch on and operate it,
famous last words. Like Paul though I am up to my ass in alligators and it
is not going to happen over night.
Since it will be on wheels, might even lend it out, but I would not hold my
breath.
Would ask one and all to keep your eyes out for an RX8 wreck that we could
low boy home minus the stuff we do not need 2004 or newer as near to SAT TX
as possible. Might even have a party at the hangar after we get it running.
Milo
I personally prefer balls instead of babbit material for bearings. You are
welcome to machine a set of the parts that I have for babbit bearings if
you like. A steel sleeve could be pressed on the shaft as a bearing surface
to oppose your preferred babbit material
It reads like you want to build a wrecked rx8 into a rolling test rig being
towed/pushed by a propeller. There are salvage rx8 occasionally on ebay
under $4k.
Ed Carver
--
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