Home machining

"Stealth Pilot" wrote

(I think the problems I'm having with my truss fuselage are tipping me
over the edge :-) ohhhhhh bugger column bending. why cant you just
build things heavy )

Are you working on your Tailwind aeroplane, or a different project?
--
Jim in NC

Stealth Pilot wrote:
I'm a lousy dentist.
what's the project?

Stealth Pilot

I'm converting auto electronic ignition parts for use on old
motorcycles. I will be making a reluctor to replace the points cam,
backing plates and mounts for the pickups.

Tony

"Stealth Pilot" wrote in message
...
-------------much snipped-----------
but you hafta admit that aerospace has way cooler x-prizes.
there is one for a home made space vehicle plonked on the moon with a
home made rocket. you hafta remotely drive up to some expensive nasa
thingy on the moon and spray graffiti on it. I think thats what the
task is...

(I think the problems I'm having with my truss fuselage are tipping me
over the edge :-)
Tthat does seem just remotely possible... :-) :-) ;_)

Peter

On Aug 17, 3:19*pm, Anthony W wrote:
.. *I will be making a reluctor to replace the points cam,
backing plates and mounts for the pickups.
----------------------------------------------------------------------------------------------

Dear Tony,

Please don't read this the wrong way...

After introduction of Hall Effect transistorized switches in the
1960's I spent two years developing an ignition system which used such
switches to replace the points on VW ignition systems. By the time I
had it perfected it was available as a plug-in module for about
$50 :-)

Mentioned here because magnetic reluctor triggering was one of the
methods I considered and discarded.

-------------------------------------------------------

Since you are working with motorcycle-scale components the odds are
that a small lathe will do about as well as a large one. I've a 7x10
that is more than large enough to let kids help their grandpa. These
are real parts (valve guides) turned out by real kids, who are
learning on a real lathe. It just happens to be quite a bit smaller
than the one grandpa is using.

In my opinion, you need to be wary of lathes & mills that are
CONVERTED to CNC. There are now a couple of small mills that are
designed for CNC from the ground up. Not sure where I saw them... in
one of the trade journals. As I recall their pricing reflected their
origins, which seems fair: I've never found any 'bargain' tools that
were worth a damn.

-R.S.Hoover

On Mon, 17 Aug 2009 19:04:51 -0700 (PDT), Veeduber
wrote:


Since you are working with motorcycle-scale components the odds are
that a small lathe will do about as well as a large one. I've a 7x10
that is more than large enough to let kids help their grandpa. These
are real parts (valve guides) turned out by real kids, who are
learning on a real lathe. It just happens to be quite a bit smaller
than the one grandpa is using.

lotsa good work is done on a Taig.

: I've never found any 'bargain' tools that
were worth a damn.

-R.S.Hoover

ditto. while I have a chinese mill that performs flawlessly chinese
tooling is crap. mainly because the alloy the component is made from
is never the correct or optimum alloy for the part.

drill bits, insert cutters, milling cutters made in china are just
utter crap quality. they wear out at an astonishing rate.
buying any of them is an absolute waste of money.

I relented a while ago and bought a chinese tap and die set to do a
job needing 12" unc. I have to admit that the die produced an
absolutely schmick thread ....but it was a full millimeter under
diameter. it was bloody hard to screw on too.

my vermont american tap and die set in UNF has never failed me for
aviation work.

the 1/2"unc was for a screw trim adjuster on a sonerai. the Sutton
(Australian) tap and die produced flawlessly mating threads of the
correct diameter.

btw Anthony an old lathe like a South Bend, if it is good condition is
a very good buy. my own lathe is a Hercus clone of the southbend
produced just after the second world war. it wouldnt pass an occ.
health and safety audit because of the exposed V belts but it is
absolutely superb for the aviation machining I do.

Stealth Pilot

On Mon, 17 Aug 2009 14:11:58 -0400, "Morgans"
wrote:


"Stealth Pilot" wrote

(I think the problems I'm having with my truss fuselage are tipping me
over the edge :-) ohhhhhh bugger column bending. why cant you just
build things heavy )

Are you working on your Tailwind aeroplane, or a different project?

eventually I will get and do a reverse engineer of the Tailwind.
mine is 25 years/680 hours old so I dont think there is too much to
worry about.

the current project is a single seat taildragger ultralight as a
learning tool. I accidently hit a shape/layout for a very conventional
design that has superb weight and balance figures so I've been
motivated to work the design to completion and build one.

persistence is the key to success in aviation and structural design.
trouble is it makes you feel so bloody dumb while you are persisting
through the learning difficulties. :-)

if it wasnt for the patience of a very schmicked up aero engineer I
think I'd be screwed. the japanese have a saying "so much data so
little understanding." my years of reading have represented just so
much data! my friend's understanding and crystal clear insight is
making this happen, slowly.

btw Jim. I have a computed drag curve for the tailwind. you will know
the classic diagram of induced and parasitic drag that has induced
reducing in a curve to nothing while parasitic increases in a curve to
maximum. the plot of resultant drag sits above the crossed lines as a
U shape. it's a classic representation.
for the W8 tailwind that classic U shape is centred on 80 knots.
what that means is that on approach if you slow down to 60 knots you
get in the area of rapidly increasing sink (which is why you approach
at 70 knots) you havent just entered the "back side of the drag
curve", you've always been in it. At 65 knots you are entering the
vertical part of the left side of the U. at 70 knots you are at the
bottom left corner. tailwinds *are* happiest flying fast.

Stealth Pilot

Stealth Pilot wrote:
On Mon, 17 Aug 2009 19:04:51 -0700 (PDT), Veeduber
wrote:


Since you are working with motorcycle-scale components the odds are
that a small lathe will do about as well as a large one. I've a 7x10
that is more than large enough to let kids help their grandpa. These
are real parts (valve guides) turned out by real kids, who are
learning on a real lathe. It just happens to be quite a bit smaller
than the one grandpa is using.

lotsa good work is done on a Taig.

: I've never found any 'bargain' tools that
were worth a damn.

-R.S.Hoover

ditto. while I have a chinese mill that performs flawlessly chinese
tooling is crap. mainly because the alloy the component is made from
is never the correct or optimum alloy for the part.

drill bits, insert cutters, milling cutters made in china are just
utter crap quality. they wear out at an astonishing rate.
buying any of them is an absolute waste of money.

I relented a while ago and bought a chinese tap and die set to do a
job needing 12" unc. I have to admit that the die produced an
absolutely schmick thread ....but it was a full millimeter under
diameter. it was bloody hard to screw on too.

my vermont american tap and die set in UNF has never failed me for
aviation work.

the 1/2"unc was for a screw trim adjuster on a sonerai. the Sutton
(Australian) tap and die produced flawlessly mating threads of the
correct diameter.

btw Anthony an old lathe like a South Bend, if it is good condition is
a very good buy. my own lathe is a Hercus clone of the southbend
produced just after the second world war. it wouldnt pass an occ.
health and safety audit because of the exposed V belts but it is
absolutely superb for the aviation machining I do.

Stealth Pilot

A few years ago I bought a Chinese metric tap and die set to fill
the gaps in my collection. The tap handle was nice. I'd sure like to
know to what standard the taps and dies were made. The finish was rough
and the dimensions were wrong. I kept the tap handle.

One of the drawbacks to owning Huot dispensers for mills, taps,
drills, reamers etc is one is aware of sizes one doesn't have. Once in
awhile I fill the empty slots knowing full well I may never use those
particular tools.

Dan, U.S. Air Force, retired

Stealth Pilot wrote:
btw Anthony an old lathe like a South Bend, if it is good condition is
a very good buy. my own lathe is a Hercus clone of the southbend
produced just after the second world war. it wouldnt pass an occ.
health and safety audit because of the exposed V belts but it is
absolutely superb for the aviation machining I do.

Stealth Pilot

You won't find a good used South Bend lathe around here or at least not
what I've seen. By the time they come up for sale, they're more than a
little worn out.

Tony

"Stealth Pilot" wrote in message
...
On Mon, 17 Aug 2009 14:11:58 -0400, "Morgans"
wrote:


"Stealth Pilot" wrote

(I think the problems I'm having with my truss fuselage are tipping me
over the edge :-) ohhhhhh bugger column bending. why cant you just
build things heavy )

Are you working on your Tailwind aeroplane, or a different project?

eventually I will get and do a reverse engineer of the Tailwind.
mine is 25 years/680 hours old so I dont think there is too much to
worry about.

the current project is a single seat taildragger ultralight as a
learning tool. I accidently hit a shape/layout for a very conventional
design that has superb weight and balance figures so I've been
motivated to work the design to completion and build one.

persistence is the key to success in aviation and structural design.
trouble is it makes you feel so bloody dumb while you are persisting
through the learning difficulties. :-)

if it wasnt for the patience of a very schmicked up aero engineer I
think I'd be screwed. the japanese have a saying "so much data so
little understanding."

To my eye, this looks like either a German or French saying; but I suppose
that many others will recognize it as their own as well. (In some business
oriented groups, the related saying is: "paralysis by analysis."


my years of reading have represented just so
much data! my friend's understanding and crystal clear insight is
making this happen, slowly.

btw Jim. I have a computed drag curve for the tailwind. you will know
the classic diagram of induced and parasitic drag that has induced
reducing in a curve to nothing while parasitic increases in a curve to
maximum. the plot of resultant drag sits above the crossed lines as a
U shape. it's a classic representation.
for the W8 tailwind that classic U shape is centred on 80 knots.
what that means is that on approach if you slow down to 60 knots you
get in the area of rapidly increasing sink (which is why you approach
at 70 knots) you havent just entered the "back side of the drag
curve", you've always been in it. At 65 knots you are entering the
vertical part of the left side of the U. at 70 knots you are at the
bottom left corner. tailwinds *are* happiest flying fast.

Stealth Pilot

The tailwind is amoung the all time standouts in low parasitic drag, and the
rapid rise of induced drag above the stall contributes to the short field
landing performance. I lack any personal experience, but have been told
that the short field performance is excellent.

Peter

"Peter Dohm" wrote in message
...
"Stealth Pilot" wrote in message
...
On Mon, 17 Aug 2009 14:11:58 -0400, "Morgans"
wrote:


"Stealth Pilot" wrote

(I think the problems I'm having with my truss fuselage are tipping me
over the edge :-) ohhhhhh bugger column bending. why cant you just
build things heavy )

Are you working on your Tailwind aeroplane, or a different project?

eventually I will get and do a reverse engineer of the Tailwind.
mine is 25 years/680 hours old so I dont think there is too much to
worry about.

the current project is a single seat taildragger ultralight as a
learning tool. I accidently hit a shape/layout for a very conventional
design that has superb weight and balance figures so I've been
motivated to work the design to completion and build one.

persistence is the key to success in aviation and structural design.
trouble is it makes you feel so bloody dumb while you are persisting
through the learning difficulties. :-)

if it wasnt for the patience of a very schmicked up aero engineer I
think I'd be screwed. the japanese have a saying "so much data so
little understanding."

To my eye, this looks like either a German or French saying; but I suppose
that many others will recognize it as their own as well. (In some
business oriented groups, the related saying is: "paralysis by
analysis."


my years of reading have represented just so
much data! my friend's understanding and crystal clear insight is
making this happen, slowly.

btw Jim. I have a computed drag curve for the tailwind. you will know
the classic diagram of induced and parasitic drag that has induced
reducing in a curve to nothing while parasitic increases in a curve to
maximum. the plot of resultant drag sits above the crossed lines as a
U shape. it's a classic representation.
for the W8 tailwind that classic U shape is centred on 80 knots.
what that means is that on approach if you slow down to 60 knots you
get in the area of rapidly increasing sink (which is why you approach
at 70 knots) you havent just entered the "back side of the drag
curve", you've always been in it. At 65 knots you are entering the
vertical part of the left side of the U. at 70 knots you are at the
bottom left corner. tailwinds *are* happiest flying fast.

Stealth Pilot

The tailwind is amoung the all time standouts in low parasitic drag, and
the rapid rise of induced drag above the stall contributes to the short
field landing performance. I lack any personal experience, but have been
told that the short field performance is excellent.

Peter

Peter another that I found during my stint with DoD. "Get the money spent.
We can find out what we did wrong later."