Hatz Biplane Association

The Hatz that my neighbor Dave Foley owns is powered with an 0290 and an oil cooler was added soon after it's first flights and it has an open cowl with exposed cylinders. My J3 runs about 210 degrees on a hot day. I would like to see my temp about 180 to 190. I have a small oil cooler that I think will be just right if I can position it to get good airflow. Going to do my best to get it under the cowl. I want to get it right the first time. I appreciate the good input. By the way, I ordered my paint today. PPG has been great to work with.

Kevin

Kevin,
I wound up adding a cooler to my Hatz. I found a cooler from a Tri-Pacer, sized for a O-290, and mounted it on the right side of the firewall, fabricated a hood so I could attach a piece of scat hose routed from the rear of the left eyebrow. Kinda ugly since it was an after thought. It runs about 210 on a 90 degree day.

Jeff Moore

Kevin,

We originally ran a little hot until adding a lip to the bottom cutout. We made the eyebrows from scratch to fit. I've never seen an open cowling with an oil cooler. I think a skull cap spinner probably helps a little too.

Steve

Congrats Kevin. Sounds great. Keep on keeping on.

Bill

Kevin, one thing to be careful for is to not get too COOL oil temps. Maybe use a smaller cooler if it's in the slipstream directly. And maybe some sort of baffling to reduce the airflow thru it for fall flying. You'll have to do some experimenting with it all. Mine is in the engine compartment (full cowl) and I built an air valve operable from the cockpit to increase/decrease air flow thru it.

I think a cooler slung under the firewall would look cool, like from the 20's and 30's. If you could maybe find or fabricate one like on the Wacos that is a round cylinder with holes through it. Neat!

Mark T

Hey Steve,

Yes I'm going to have exposed cylinders same as the cowling on your Hatz. Have you had any temp problems on a 90 degree day? I hope to get the same look as yours. Did you modify J3 eyebrows to fit the Lycoming and get sufficient cooling?

KC

You're going to have an 'open' Cub cowl?

Steve

Hello Hatzers,

With the help of an experienced A&P, my 0-290-D2 is completely assembled and ready. I purchased a J3 Cub nose bowl from Univair and will have to complete the cowling and come up with a way to install an oil cooler. What do you guys think about hanging an oil cooler right out of the bottom of the cowling back at the firewall? I'm thinking this might give the Hatz a nostalgic look and be effective hanging in the slipstream. I know it will add another component of drag, but I know there will not be much room with the carburetor being more aft toward the firewall. All the steel parts have been bead blasted and covered with a two part automotive epoxy primer. I finally found the color I want and will be ordering my paint from PPG Products right away. Planning to paint the steel parts soon and start covering. I am planning on covering using the Airtech system up through primer and PPG paint for the top coats. I still have a long way to go but I'm hoping to start painting when it gets cooler and the humidity drops. I never get tired of working on the Hatz and can't wait to go flyin. Will try to post some pictures soon.


Kevin Conner