Bad ideas tend to generatre great inventions....lets keep our thinking caps on people

How about delebrately shorting a lipo battery on air.... .. very simple circuit and light weight too, but a bit expensive.. I bet it should generate a lot of smoke (and heat)... 

Wouldn't some of the regular diwali (and other festival) "Pataka"s work just about the same... and cost effective too !  One will get some "light" also as added bonus

Now if someone can propose a remote ignition mechanism (other than shorting a lipo, that is )

Oh come on Anwar... we want some hi-tech smoking stuff...

BTW, electronic ignitors are not that difficult to make the gud old potassium nitrate/sugar mixture properly placed on a broken 3V torch bulb should do the trick... Rocketry guys use it a lot.

my crazy idea 
the valve can be a servo pinching on the silicon tube

Engine heat is not sufficient on a .46 engine plus added weight of smoke oil/tank etc is not advised.

Guarav,
I am sure some one will come up with an idea to heat up the engine. May be something on the lines of what Izmile suggested should work  

Anwar,
No they would not, been there done that,
It will give you sound and flash but hardy any worthwhile smoke.
In the days of yore for CL combat shows we used to fix small crackers (the ones locally called  lari like 100 wallas 500 wallas etc but on our models it use to be cut down to may be 5 or 10 ), use DT fuse and then couple of us flying together  simulate combat during displays.

Sunlike it will work.
From what I understand from your diagram is that the valve you are referring to is meant to control pressure to the smoke oil tank. There is a much cheaper solution for that. Pass the tube through a suitable id wheel collar, and adjust the pressure by turning in or out the set screw. You can add a bit of thread windings on either side of the collar and drip some glue/cyano to ensure that te collar wont move
But that would be a fixed solution and you can not switch it on or off.

However the challenge in getting your engine to smoke is not how to get the smoke oil to the engine, but how to sufficiently heat the oil for it to burn incompletely (the trick lies in getting the temp right where neither is it fully burnt nor unburnt) If this is not right all you would get is a good spray of the oil on your airframe or smoke trails like a truck  

If any one is interested in how to smoke
please read here http://www.soldcentralfl.com/flyingpenguin/smoke.htm

Hi Divay, If u want a tried and tested solution--

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7324

Can't see how it will solve the main issue on these size engines, lack of heat !   This is just a pump from a good brand.

I agree with Anwar ... the product listed by crazypilot will be good for a gasser but not for a .46 size plane....hmmm

for heat use a bigger prop like 15X8. otherwise use smaller prop like 6X4

15x8 prop or a 6x4 prop .. will only lead to the engine smoking up in fumes thereby generating smoke as well as a pile of balsa...

but this is what u wanted. No need to say Thx.

hahahah ur funnypilot not crazypilot hahahah

Crazy... PM me what YOU are "smoking" tonight... thinking about how to smoke an engine   Seems like good stuff

PS: Yes, old boring joke !

How about using an actuator to stick some baking soda into a bottle of vinegar?

Just joking.I guess it is really impractical.

Hope you find a solution.

1:1  kerosene and diesel will produce pure white smoke

madhavan, thats what suryakiran does with the added dye for red and green colour, but then the weight penalty?

Too late to this topic,
Still, A 1:1 mixture of Kerosene and Glycerine might work even with Lower temps. Glycerine has flash point of 160 C and it will ignite Kerosene as well, Should try it on my own.

just use some white phosphorous with the oil tank to heat the oil
white phosphorous has an  ignition  temperature of 36 c which is more than enough