http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar & needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a
real man's engine.

I got a 5-44 tap & die for the project, which is a bit coarse but should
work. Now all I need to do is resist the urge to try to make my own
5-64, 5-72, 5-80 or other insanely fine thread tap (and single-point
thread spraybars to match), and just make stuff with what I got.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Tim Wescott" wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar & needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:
On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be
a real man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott


Ever chop streamers ? Waaaay back in the day , when I was young and had
SOME eye/hand coordination ... We flew "flying wings" - just the wing ,
minimal tail usually on twin booms . Drag a crepe paper streamer . Two guys
in the circle , ya try to chop off the other guy's streamer .
We broke a lotta balsa .
--
Snag
Wannabe Machinist

In article ,
Tim Wescott wrote:

On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

I was deep into C/L as a kid... flew mostly combat and stunt, but near
the end dabbled in a little jet speed.[1] This was back in the late 60's
when everything to do with model aircraft was 'real man'. No starters
(other than the speed folks), no mufflers, no electric fuel pumps, no
wrist tethers, no nothing. Just fun.

I saw where one of C/L's great innovators, Bill Netzeband passed away a
few of months ago... brilliant man, and one of the nicest guys there
ever was.

Erik

[1] To which I attribute to my less than stellar hearing.

On 09/17/2010 10:13 PM, Erik wrote:
In ,
Tim wrote:

On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

I was deep into C/L as a kid... flew mostly combat and stunt, but near
the end dabbled in a little jet speed.[1]
(snip)
[1] To which I attribute to my less than stellar hearing.

Those pulse jets are LOUD. I've never seen one in person, but just
listening to them on youtube it's obvious that the stories about them
are true.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 09/17/2010 09:51 PM, Snag wrote:
Tim Wescott wrote:
On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be
a real man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott


Ever chop streamers ? Waaaay back in the day , when I was young and had
SOME eye/hand coordination ... We flew "flying wings" - just the wing ,
minimal tail usually on twin booms . Drag a crepe paper streamer . Two guys
in the circle , ya try to chop off the other guy's streamer .
We broke a lotta balsa .

I never had anyone to fly combat with, but boy I sure wanted to. My
cousin and I were going to build combat planes -- his came out with a
bent wing, then we warped the cylinder on his engine flying it (way too
lean run), then I didn't have the $$ for an engine.

I still have my kit -- a Jr. Satan. And his engine -- a Cox Medallion
with an oval cylinder and piston. It'd be fun to get something built.

These days the combat flyers buy planes in bulk from the Chech Republic
or other former Eastern Bloc countries -- combat's popular over there,
and prices are low.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Those pulse jets are LOUD. I've never seen one in person, but just
listening to them on youtube it's obvious that the stories about them
are true.

They sure are... to the extent they literally gave my dad nose bleeds.

They were hard to wrap your head around too... quirks & idiosyncrasies
by the thousand, and far as I could tell, no two people had the same
opinion about anything concerning them.

Erik

On Fri, 17 Sep 2010 20:42:56 -0700, Tim Wescott
wrote:

On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.


You can have a throttle, flying control line. I believe that some of
the control line scale guys used it for a while. The two control lines
control the elevator and the (usually) upper control line was a single
wire Mono Line control linked to the throttle.

I've never flown one but have seen photos of some of the scale rigs
that had them. I think it was used to shoot touch and go landings.

Cheers,

John D. Slocomb
(jdslocombatgmail)

On Sat, 18 Sep 2010 00:12:10 -0700, Erik wrote:


Those pulse jets are LOUD. I've never seen one in person, but just
listening to them on youtube it's obvious that the stories about them
are true.

They sure are... to the extent they literally gave my dad nose bleeds.

They were hard to wrap your head around too... quirks & idiosyncrasies
by the thousand, and far as I could tell, no two people had the same
opinion about anything concerning them.

Erik

I flew them for a while. They were usually a "free" trophy if you
could get off the ground. I developed an all aluminum airplane that
allowed the engine to be mounted very close to the fuselage and
finally got the motor to be reliable. 135 MPH every flight and (IIRC)
a trophy every contest.

Cheers,

John D. Slocomb
(jdslocombatgmail)

"Tim Wescott" wrote in message
...
On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a
real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com


Don't you fly RC?

RogerN

On 09/18/2010 08:02 AM, RogerN wrote:
"Tim wrote in message
...
On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a
real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com


Don't you fly RC?

I didn't say that _everyone_ who flies RC is a sissy. But there are
sissies who fly RC.

I'm taking up control line after a long hiatus, and finding out that
it's more fun to fly than RC. RC is way more fun to watch someone else
fly, and you get to be fascinated by all the technology. But the direct
connection you have to the plane in CL makes a big difference.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 09/18/2010 05:24 AM, J. D. Slocomb wrote:
On Fri, 17 Sep 2010 20:42:56 -0700, Tim
wrote:

On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.


You can have a throttle, flying control line. I believe that some of
the control line scale guys used it for a while. The two control lines
control the elevator and the (usually) upper control line was a single
wire Mono Line control linked to the throttle.

I've never flown one but have seen photos of some of the scale rigs
that had them. I think it was used to shoot touch and go landings.

Two of us in my RC club are picking up CL. Jim used to fly three-line
all the time. It's actually more complicated than just a line going to
a spare bell crank -- there's an arrangement that keeps the same tension
on each line as the plane flies, and if you get the "store bought" bell
crank there's something to keep the throttle from interacting with the
elevator -- too much.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On 09/17/2010 07:04 PM, Tim Wescott wrote:
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar & needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a
real man's engine.

I got a 5-44 tap & die for the project, which is a bit coarse but should
work. Now all I need to do is resist the urge to try to make my own
5-64, 5-72, 5-80 or other insanely fine thread tap (and single-point
thread spraybars to match), and just make stuff with what I got.

Done: http://www.metalworking.com/dropbox/venturi_done.jpg.

Seems to work well, but I've only run about an ounce of fuel through the
engine -- time to run some serious tests now.

Between the "1/16" inch music wire being a hair over, the threaded part
of the spraybar being a hair bent, and the needle valve nut being
intentionally split to prevent things from rattling out of kilder, the
needle is hard to turn.

I'm hoping that the needle will settle out to a decent amount of
friction, without getting too loose. Fortunately I'll be able to adjust
the split nut.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Tim Wescott" wrote in message
...
On 09/18/2010 08:02 AM, RogerN wrote:
"Tim wrote in message
...
On 09/17/2010 07:10 PM, Buerste wrote:
"Tim wrote in message
...
http://www.metalworking.com/dropbox/venturi.jpg

Tomorrow: a spraybar& needle valve. That's a 5-40 screw where the
spraybar belongs. It's on an OS Max 25, formerly RC but soon to be a
real
man's engine.
snip

"Real man's engine"?

Control line. No throttle. Let the plane go, and either fly for six
minutes or crash.

Sissies fly RC.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com


Don't you fly RC?

I didn't say that _everyone_ who flies RC is a sissy. But there are
sissies who fly RC.

I'm taking up control line after a long hiatus, and finding out that it's
more fun to fly than RC. RC is way more fun to watch someone else fly,
and you get to be fascinated by all the technology. But the direct
connection you have to the plane in CL makes a big difference.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com


Of the RC flying I've done I like the helicopters the best, it's a lot
easier than it used to be due to electronic gyroscopes, computer radios, and
better flying more reliable designs. It used to take a lot just to make a
helicopter smooth and reliable, they have taken much of that difficulty out.

I haven't done it yet but I'm interested in getting an economical electric
plane and flying it first person view using a video camera, transmitter, and
video goggles. There are a lot of videos of this setup and it looks like a
great use for a model plane. There is a Hobby Lobby Telemaster electric
that looks like it would be good for FPV RC.

I haven't flown control line beyond the COX toys that aren't very
responsive. Have you done the high speed pulse jet C/L yet? I'll bet
that's not for sissies!

RogerN

On 09/18/2010 03:03 PM, RogerN wrote:
"Tim wrote in message
-- snip --

I haven't flown control line beyond the COX toys that aren't very
responsive. Have you done the high speed pulse jet C/L yet? I'll bet
that's not for sissies!

No, I haven't done the pulse jet thing -- and no, that's not for
sissies. There are (or were) some deranged individuals, I think in some
SW desert state, who were experimenting with pulse jets on RC planes.
Even with it being RC, I don't think that's for sissies either.

If you ever get your hands on a bigger control line plane you will be
amazed at the difference. Your connection to the plane is solid, and
the whole experience is far more immediate (particularly when you're
getting into shape and you're saying to yourself "if I fall down I crash
this thing"). Even a decent balsa plane with an 049 on it is in a
different world compared to the barely-flying toys that Cox coughed out.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

"Tim Wescott" wrote in message
...
On 09/18/2010 03:03 PM, RogerN wrote:
"Tim wrote in message
-- snip --

I haven't flown control line beyond the COX toys that aren't very
responsive. Have you done the high speed pulse jet C/L yet? I'll bet
that's not for sissies!

No, I haven't done the pulse jet thing -- and no, that's not for sissies.
There are (or were) some deranged individuals, I think in some SW desert
state, who were experimenting with pulse jets on RC planes. Even with it
being RC, I don't think that's for sissies either.

If you ever get your hands on a bigger control line plane you will be
amazed at the difference. Your connection to the plane is solid, and the
whole experience is far more immediate (particularly when you're getting
into shape and you're saying to yourself "if I fall down I crash this
thing"). Even a decent balsa plane with an 049 on it is in a different
world compared to the barely-flying toys that Cox coughed out.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com


A friend that I used to fly RC with was into control line before RC and was
telling me about some of the planes, he said after they are set up good he
could fly figure 8's without looking at the plane, he said it would follow
his hand. When we were young my brother bought a balsa control line kit for
049's, it flew good but we were used to flying short lines in the yard, had
to miss trees and cars, so it was a bit wild compared to the COX plastic
planes.

RogerN