Author Topic: 1/33 Harvard Mk.IV Exhaust Instructable  (Read 283 times)

Dave Winfield

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1/33 Harvard Mk.IV Exhaust Instructable
« on: November 07, 2014, 10:05:48 AM »
Obviously the Harvard and Texan are basically the same plane.
Built from the same plans anyway...although the Harvards were built in Canada
by two different companies under license from North American Aviation.

The most widely used Harvard being the Mk.IV version built by the Canadian Car & Foundry Co. (in Ontario).

Up to now I have only produced AT6 Texan kits.
These of course, were originally based on Ken Uhrig's Harvard Mk.IV paper model.
I helped Ken digitize his Harvard kit and ended up with a whole new version in digital vector format.

Recently I started work on an update of Ken's old Harvard kit (at his request) and I am helping him put out a new version
of his model. In return he has given me his blessing to release some Harvards and I am starting with a kit I created when
I was first creating my Texan.   I'll be releasing that kit very soon.

One of the interesting things about the Harvard, is the modified exhaust system.
The "cold weather exhaust" features a much longer outlet pipe, that runs down the side of the fuselage.
Inside this lengthened exhaust pipe is a smaller tube that is open at the front of the aircrcaft to allow
outside air in...and it directs air into the cabin of the aircraft. Because the smaller tube runs the length of the main exhaust pipe,
it is heated by the exhaust gases, and in turn heats the air entering the cabin.

My Harvard kit has a simplified version of the "cold weather exhaust".

Assembling the cold weather exhaust is a tad more difficult than the AT6 exhaust.
It is five pieces (instead of one).
These are small pieces with some very thin sections, requiring very careful cutting/
The parts easily "butt" together, with no tabs or special attachments, but their small size demands patience and concentration.

You also need to make sure the parts are properly aligned during assembly,
and shape and trim the outlet part (before installation).

The kit includes basic assembly instructions for the Exhaust, but I decided to go a little further.
I have created a diagram sheet with a bit more information
and provided some photos of the completed exhaust from various angles.

(The photos are black and white to represent any Harvard kit)

Download a larger version (PDF) of this instructable:



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Re: 1/33 Harvard Mk.IV Exhaust Instructable
« Reply #1 on: November 08, 2014, 07:49:42 PM »
Thank you Dave, this will be extremely helpful.

"Fast is Fine, but Accuracy is Everything" - Wyatt Earp