Thought I would pass along some info on the smoke system in my Extra 300-S.  The 300S started out with a ST 90.  I plumbed up one of the Dubro smoke systems.  This system has a valve body that has two fuel tubings running through it.  The valve is driven by a servo - OFF pinches the two lines closed - ON opens them up.  The system runs on 2C crankcase pressure.  One line runs between the crank case pressure tap and the tank. The other line runs between the clunk in the oil tank and the muffler.  A one way check valve in the pressure line keeps the pressure up in the tank.  This system worked well and I got lots of good smoke.  I then converted the 300S to 4C power.  I installed a Sato 120.  A 4C does not have crankcase pressure so I tried using muffler pressure.  This almost worked but I didn't have the volume of smoke I wanted and at time the smoke was intermittent.  A search of smoke equipment turned up the Sullivan smoke pump.  Probably would work but is pricey, ($100). The other item that popped up in my search was the Perry Oscillating Smoke Pump, ($40).  Price was much better and it looked easy to install.  I bolted the Perry to the Sato 120 per the instructions that came with the pump.  I plumbed it up between the oil tank and the muffler.  So now the muffler pressure is pushing on the oil supply and the Perry pump is pulling on the oil supply.  A couple of check valves and the system was ready for a test run.   I haven't flown it yet but on the ground it  makes tons of billowing white smoke.

Anyway if you are wanting smoke on a 4C the Perry Pump along with muffler pressure seem to work well.

I had a Harry Higgley & Son's smoke sustem once. They don't wear out but the thing gave me more trouble than it was worth. 

I sold it as a "Lot" with of over 100 R/C items on ebay.

Charles

 

I agree it is a bunch of trouble but every Extra 300S video I have ever seen has smoke.  My control handle has 7 functions so it really was no biggy with a 120 class engine.  Hay it's the coolest thing I have ever rigged and I have never been able to do a great missed approach!
    

John,

Could you please list the 7 functions?

Charles

CH 1 Throttle
CH 2 Ailerons
CH 3 Rudder
CH 4 Smoke
Ch 5-6-7 spares.

Aleron and rudder are used for preflight ground check (helps realism of flight score) and I can ground steer with the rudder.  In flight they are fixed at wings level and turn Right.

Looks like your elevator is servo controlled?

There's a link from your B/C to a pot? 4 ea. std. servos with 3 pushrods going aft, 1 pushrod is throttle going fwd., 1 ea. small servo for the smoke. That's 5 servos.

I thought the elevator had to be mechancally linked to the B/C?
Apologies if I'm wrong on this.

Don't forget the two servos for the ailerons for a total 7.  The elevator is controlled by 2 servos.  Other threads have discused the legality of a servo controlled elevator.  As it turns out AMA rules permit it. FIA rules do not.

See: http://stunthanger.com/smf/index.php?topic=3701.0

John,

Not to be funny,

Could you fly this model sitting in a chair outside the circle if the "single" line was teathered?

There's a new event.

Cup holder and all.

Charles

Just think when they approve 2.4 ghz for controll of U-control you could sit at outside and fly-fly-fly.    I have heard of such already being done.  Not sure why but hay - whatever!   of course if the string breaks it's then call RC....................