Ace Venturi -- Metalworking for the Day

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
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<snip>
"Real man's engine"?
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On 09/17/2010 07:10 PM, Buerste wrote:

Control line. No throttle. Let the plane go, and either fly for six minutes or crash.
Sissies fly RC.
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Tim Wescott
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Tim Wescott wrote:

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 .
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Snag
Wannabe Machinist
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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.
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On 09/17/2010 10:13 PM, Erik wrote:

(snip)
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.
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Tim Wescott
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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
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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)
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I have a brand new Dynajet in a display cabinet. Coud never bring myself to discolor it by firing it up. JR Dweller in the cellar
wrote:

-------------------------------------------------------------- Home Page: http://www.seanet.com/~jasonrnorth If you're not the lead dog, the view never changes Doubt yourself, and the real world will eat you alive The world doesn't revolve around you, it revolves around me No skeletons in the closet; just decomposing corpses -------------------------------------------------------------- Dependence is Vulnerability: -------------------------------------------------------------- "Open the Pod Bay Doors please, Hal" "I'm sorry, Dave, I'm afraid I can't do that.."
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wrote:

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)
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On 09/18/2010 05:24 AM, J. D. Slocomb wrote:

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.
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Tim Wescott
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Don't you fly RC?
RogerN
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On 09/18/2010 08:02 AM, RogerN wrote:

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

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.
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Tim Wescott
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wrote in message

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
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On 09/17/2010 07:04 PM, Tim Wescott wrote:

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.
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Tim Wescott
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