Q-talk 146 - Jon Swenson - Tri-Q-Vair
- Category: Q-Talk Articles
- Published: Monday, 25 April 2011 20:00
- Written by Jon M Swenson
- Hits: 5844
by Jon Swenson
[EDITOR’s NOTE: Frequently someone will say something on the Q-list that sparks my curiosity. Usually this means that someone has mentioned a fix for a problem I’m having on my own project, or are attempting to do something that I’ve only just considered. When Jon Swenson mentioned that he was putting a Corvair engine in his Tri-Q, I just needed to find out more info. After all, I’m currently teaching myself to weld so that I can fabricate an engine mount for my own Corvair powered project. So, I sent Jon a quick e-mail and he ended up mailing me a CD with several PowerPoint slides from a presentation he had recently given about his project.]
I bought the Tri-Q project on eBay in May of 2002. It had been involved in a “Hard Landing” incident that collapsed the nose gear.
The first item on the “to do” list was to install the front gear.
Then I needed to build up a motor mount to accommodate the Corvair and the new nose wheel. I ended up building four motor mounts before I was satisfied. Below is a picture of the final design under construction.
Just so you know I wasn’t kidding, here’s a shot of Mount number three:
I loaded up the final design to 10 G’s using William Wynn’s technique. In the photo below you can see the 10 foot lever with 240 lbs. of cement.
This photo shows the deflection of the mount before and after testing. . .
. . . and the finished mount attached to the airframe:
Here’s another shot with a scrap case attached to the Motor Mount.
The front gear plate is attached to the main motor mount. When I removed the old gear the 4 mounting holes were work elliptically, indicating that the leg mount was moving from side to side.
In the firewall recess for the O-200 I placed the dual fuel pumps and coils.
I turned the rear flywheel spacer and the front prop hub spacer on my granddads 1941 Atlas Lathe. . .
. . .and milled the bolt risers on the rear housing to create more clearance for the flywheel.
Here’s my oil cooler and filter set-up on the pilot’s side of the firewall.
I made several Stainless Steel plates to act as carry throughs.
The magnetic tach sensor mount is combined with the distributor hold down.
On the copilot side I installed a gascolator and fuel pressure switch.
I put an off the shelf oil breather in the top cover of the rear accessory case. The final starter mount is visible here.
This shows the regulator, connector block, and the primer solenoid.
I have pressure plenums for cooling. They have since changed from this photo.
I wound electric fence wire on the lathe then applied to the exhaust to increase the heating area.
To make a new cowling for the Corvair I used insulation foam and plywood formers.
Here is the rough cowling shape before covering the whole thing with a layer of sheet rock compound.
Still very rough. This is one of the most time consuming parts of the project and it is still not finished.
I made molds for the panel and center tunnel then fabricated them from epoxy. These both evolved from this point. . .
. . . and here’s the final panel layout.
FAST FORWARD to 2010
Preparing for the first engine start.
The engine turned over and coughed but wouldn’t keep running.
After talking on the phone with my “on call” experts, I added oil to the cylinders and reduced the amount of primer and throttle I was using. A week later, it turned over four or five times and then fired up! I have run it three or four times for a total of 28 minutes.
[EDITOR’s NOTE: More photos of Jon’s build can be seen in his photo album on Quicker!]