Smoke and wet bottoms …

I haven’t been using the smoke system that much recently …post the engine rebuild .. but, over the last few flights where I have used smoke I’ve been getting an excess of unburned smoke fluid covering the underside of the aircraft.

The areas most affected are driven by the airflow and so, undercarriage (being quite exposed) gets a direct ‘hit’ main and tailwheel ..the rest goes just behind the main gear on the underside of the body … then under the lower body with some catching the tail

I made contact with smoking airplanes in the US who supply the kit to check that my attempts to lean off the oil mixture was not working and see if they had other ideas.

Their first thought was that it might be a single or dual blocked injector .. the injectors are strapped to the exhaust stacks and protrude through small holes so atomising the oil spray into the hot exhaust.

The effect of a coked or partially blocked atomiser would be to allow the oil to build into globules and so be too ‘thick’ to burn … but instead trickle and run down the tube … then exit in the flow and spread

Removing them revealed that they were clearly coked and blocked

A follow up email to Smokin Airplanes in the US ..gave an almost instant response with a detailed sequence for how to (safely) clean these… amazing service 😊👍