Thanks... the more information... the better.

 I've tried a number of methods to remedy this problem; covering areas of ingress, additional air vents etc. No real improvement. I've concluded that the principle cause is the engine exhaust being too close to the main landing gear strut openings.

 The lower pressure caused by the fuselage shape and the closed canopy is sucking the smoke, and probably dangerous CO2, in like a vacuum.

 I'm thinking that an exhaust extention of 10"-12" will do the trick. Just need to get that exhaust a bit further away from the fuselage, below & behind the strut openings. This leads me to my question about modifying my exhaust pipe.

 What is the best way to go about this? My exhaust is 3.00" dia steel. Have other members simply welded on a sleeved section? Maybe a butt welded section? Are there appropriate automotive applications for this? I'm not comfortable with a simple bolt on or band clamp attachment. Also, there is the issue of adequate exhaust pipe support due to the increase in weight & arm. Perhaps this would be negligable?

 I'd like to hear how other members have dealt with this.

I had a good trip - short (2 days), but good. I spent a bunch of time at the gas welding workshops to see if I could brush up and fine tune the welding skills I had taught myself over the past year. I actually had never seen anyone gas weld close up, before, so it was great to see the methodology of more experienced guys, and I picked up some tips that I will be trying soon.

I also attended an aluminium gas welding class - the first they had done in 15 years or so. Naturally the teacher made things look real easy :0|, and naturally, it wasn't. Still, I may play with that at some point...'just so one day I can say 'I can'.

The biplane forum get-together went well on Tuesday evening at the beer tent. I am guessing we had around 30-40 show up, with 10-20 at any one time - it was a surprisingly good turnout with a good cross section of builders  - one minute I was chatting to a model 12 builder from Australia, the next minute I was talking to a Pitts, Toot, Acrosport or Skybolt guy, etc. Most people introduced themselves with a hearty 'thanks for providing the forum', I probably heard that 20 times that evening, thanks for the kudos guys.

I noticed the Acrosport guys have a little section in a tent by the homebuilders hangar area...maybe one year we need to do something similar - push all these bipes, etc.....

Most plan sets now seem to come with a bunch of high res pictures detailing everything.