Making smoke

cardiffrob · Post by **cardiffrob** » Sat Oct 10, 2009 9:59 am

I was wondering how it is done.

How much oil, how often, does it effect performance, how high up the exhaust does it have to go, how much pressure is needed, does it need a non-return valve, etc etc etc.

It is all in relation to the idea of spot-marking your progress to leave a visible trail in the sky to help avoid mid-airs.

Just playfully pondering an idea of mine.

Ian Melville · Post by **Ian Melville** » Sat Oct 10, 2009 8:00 pm

You're will need to change you're nickname from Foggy to Smoggy

Ian Melville · Post by **Ian Melville** » Sat Oct 10, 2009 8:05 pm

Oops forgot the link

http://www.acroflyer.com/smoke_system.htm

cardiffrob · Post by **cardiffrob** » Sat Oct 10, 2009 9:27 pm

Any ideas about how far down from the valves you need to go before injecting the oil? Too far and it won't burn and if too close it might bu66er the engine?
My idea was to have a simple squirt-pump like the items used as replacements for Ki-gas pumps so that individual puffs could be made, using minimal quantities of oil.

gasax · Post by **gasax** » Sun Oct 11, 2009 8:00 pm

I recall an article from the Kansas city Flyers - who had a variety of WW1 replicas, generally with VWs.

They used windscreen washer pumps with the associated bottles. Only gives a couple of minutes smoke - but would probably be more than enough.

They tried to get the injection point close to the exhaust valve to ensure the oil burnt. A non-return valve and heat resistant piping etc are quite important!

cardiffrob · Post by **cardiffrob** » Sun Oct 11, 2009 8:36 pm

From other websites, it looks like the oil refered to as "Concrete mould release oil" is the stuff to use. Best preheated with a copper pipe running near the manifold and then a fine squirt into the manifold about 6 inches down. Adding smelly aromatherapy oils is a common dodge at airshows to placate the nimbies.
It seems that the oil doesn't burn but merely vapourises somewhat.

Morris screen washer pump and a one-way valve, then.

Ron. Rather than print my callsign in morse, maybe I could print my Mode S hexadecimal identifier code?

Ian Melville · Post by **Ian Melville** » Sun Oct 11, 2009 8:56 pm

Mode Smoke

john pearce · Post by **john pearce** » Thu Oct 15, 2009 1:36 pm

Shell produce smoke oil specifically for the purpose - environmentally friendly rather than diesel used historically . It is branded " Ondina" but believe only available in 50 gallon drums.

A friends eagle had a car windscreen washer type pump and home made oil tank but it was never successful. He has since replaced with the full system , now marketed by Aircraft Spruce which was originally manufactured / sold by www.smokinaeroplanes.com as a " visual TCAS". It uses a Sureflow diaphram / demand pump of from memory 120ltrs/min. The same type of pump that the ATV Quad bikes use for sprayers. Google sokinaeroplanes and you will find his web site.

This high demand pump helps to " vaporise" the oil on contact with the hot exhaust. I have fitted three now, very successfully and usually fir the injector about 9 " from the cylinder where it is still hot enough. You can have twin injectors for both sides of the engines if required.

ZuluAlpha · Post by **ZuluAlpha** » Wed Nov 11, 2009 8:58 pm

Diesel, red or clear road fuel works OK but smells. Ondina is about £1.50/litre and is clear and doesn't smell. You can get a 205 litre drum from the Yak aerobatic people at Compton Abbas.

The oil vapourises rather than burns so you need to inject it at the hottest place available. Right next to the cylinder is best but then you need one injector per cylinder. The second best place is at the junction of the 4:1 exhaust system.
Make the nozzle by drilling a hole through the exhaust and then using jubilee clips to hold a flange in place with the nozzle welded through the flange. This allows the nozzle to be removed when blocked. Arrange the nozzle to provide a spray of oil.
Connect the nozzle to the pump/solenoid with a fireproof flexible hose.

You will need between 1 and 2 litres of oil per minute (this is for an IO360). Believe me you need a lot of smoke oil.
Best to fit an electric pump and also use a diesel fuel solenoid to shut off the flow when the pump is off. These are quite cheap from a motor factors. Most pumps have seals and plastic parts that don't like diesel. So you will have to replace them every year or two. So buy a cheap pump and replace it every couple of years or go for an expensive dieselproof pump.

You will find that the back end of the aircraft will get covered in smoke oil. Diesel may attack fabric or rubber seals so be prepared. Red diesel will stain the back of the aircraft red.

Despite all these issues smoke is good fun!!

ZA