Originally Posted by RDJeff

This morning I undertook another scary operation, cutting off the nose of the fuselage. I had carefully marked the location of the firewall face all through the build, and the sawing went perfectly.

Now I can fuel proof all of the interior bits, then start measuring and cutting for the engine clearance.

looks very nice!

Thanks again!

Very nice workmanship!! You are a craftsman, good to see there's still some of us out there who still build!

Thanks for the kind words Steve!

This morning I started cutting up the engine cowl to accomodate the engine. This is pretty traumatic! First I cut the cowl to fit the cylinders, then a hole was cut for the carb intake scoop, followed by reliefs for the mixture screws and the blue choke lever. Lots of fiddling around, but I got it done.

I held off on the bottom of the cowl where the exhausts will be, as I'm still playing with ideas for that. The stock mufflers for the Tartan are just boxes with 4 holes in each. In order to use these mufflers, I'll have to make some big cuts and remove most of the cowl bottom. Instead, I've been pondering making exhaust manifolds that would just bring a pipe out of the cowl bottom, then attaching a muffler or mufflers to those pipes.

I don't have a TIG welder, and don't really have access to one, so I've looked into brazing aluminum, and it looks like it would work. Then I thought why not make them out of steel, it would be more likely to succeed. I'll see what I have laying around as far as plate and tubing go.

I think I have an easier solution to the muffler problem. The mufflers can be installed after the cowl is in place, so the holes in the bottom of the cowl only need to be big enough for the mufflers to pass through. I'll cut the cow some more later today.

I found that 6mm K&S aluminum tube fits the muffler outlets perfectly, so I cut some tubes to staggered lengths to look a bit like headers on a car. It should be easy to braze these in place. The tubes will at least get the exhaust below the bottom of the fuselage.

I was able to braze the tubes into the muffler, and I think it went pretty well, for my first try with a MAP gas torch, and the Bernz-o-matic brazing rods. Next, I finished up cutting up the cowl to fit.

thats engine lookslike a beast in that cowl.(in a good way)...….very cool idea on the staggered exhaust stacks too...

you mentioned making a muffler out of steel? do you weld? i know many will say its junk, but ive been tinkering with the idea of getting cheap welder from harbor freight...i know it could come in handy for very small jobs...

I have the cheap welder from Harbor Freight. I built a mini bike with it, and it all held together. I also built a lot of big garden trellises out of 3/4" square steel tubing. I've been using those for at least 8 years and none have come apart yet.

The main disadvantage of this welder is splatter and messy lumps. The better your welding skills, the fewer the lumps, but it always splatters.

I got a real MIG welder recently for auto body work. It's noticeably cleaner once you learn how to use it.

I don't know how much of a beast this engine will be, I'm going to start with a 20 x 8 prop. I just like the engine for it's cool factor!

I wasn't going to build an actual muffler of steel, just the manifold and downpipe of steel, then aluminum for the muffler. The way I went means I don't have to make anything.

I do own a Miller MIG setup, but it is out in the back shed, and I don't feel like hauling it all out. I was thinking I'd just bronze braze the steel parts, but now I don't need to.

glad to hear its a decent unit Balsaworkahop.....

abou the engine, i do remember seeing them in the Tower Hobbies BIG catalog as a kid in the 90s, around the same time the Mac Minarellis and Fujis wefre popular(sp) cool looking engines

The engine is built really well! It was designed for industrial use, then adapted for hobby flying. It has roller bearings on both ends of the rods, and all of the castings are stout and nicely done. I expect the engine will last quite a long time.

Care to shed any light on how to Braze? Is is like soldering? Looks cool.

There are some good YouTube videos about it that are helpful. You just need to heat the base material hot enough to melt the brazing rod. It melts at ~750F, while the base melts at 1200F, so just be careful not to melt the base material.

A bit more progress to report. I glued up the tail wheel support plates, so that is good to go. Next, I glued on the ventral fin, and drilled it for the rudder hinge The verticals will get covered with a fabric covering, then glued in place, and then the whole works will get painted with System III paint in dark blue. The wings and horizontals will be covered in yellow film.

I decided to add a hood scoop to cover the carburetor intake, it looks like an old S/S Dodge!

Finally, I set all of the pieces in place to get a idea of what the plane will look like.