Hatz Biplane Association

Currently there is only one Hatz flying with the R3600 (John Kerr in Utah) though there are several more under construction (5 or 6 including myself).

There are no CG issues with the R3600 on the classic. The Classic was designed around the Lyc O-320 which weighs ~275lbs and the Rotec R3600 weighs the same (give or take a pound or two). In fact, Jeff Shoemake (Hatzclassic.com) built the fuselage and engine mount for John Kerr's Hatz and has updated the Classic plans to include drawings for the R3600 - different engine mount, longer gear legs, and a couple other items.

I'm very impressed with the R3600. Unfortunately, I have not been able to fly one, but everything I've seen from their product and reviews says it is a solid engine. I put a deposit down @ OSH last year and spent some time talking with Paul from Rotec - great guy and very helpful. I also had the chance to see John's Hatz and his R3600 installation which looked good and I don't see any drawbacks to using that engine.

Doug,

Sounds good. Actually, beyond good, more like "exactly what I was hoping to see".

Everyone,

Consider me another Hatz-er. I have a bunch of questions to ask, but I'm on a business trip right now, flight was delayed because of the bad weather, and someone decided to schedule the meeting for 7am (grumble...). I'm going to bed now, but will post more tomorrow evening. Thanks for all of the answers so far!

Dustin

Going to move my comments over to the Hatz Classic area...

My Hatz Classic might be the only one flying with the Rotec 3600 for a little while yet, there is half a gaggle of people building that combination right now in various stages of completion. Weight and balance was not an issue, the weight of the R3600 is very close to that of the O320 that the Classic was designed for. The center of mass for both engines are placed in the same location relative to the firewall, but the thrust line was lowered 6 inches for the Rotec. Change one thing and other things need to be changed as well; with the lowered thrust line all of the formers forward of the rear cockpit back had to be relofted to flow smoothly to the engine/exhaust collector ring.

I have found that 50 degrees is about my personal limit for cold weather flying without some sort of help with extra clothing. The cover on the front pit helps, along with a good collar scarf to protect from the back draft. Oil temperature is the next issue because with the cylinders hanging out in the wind it is difficult to even get the 1+ gallons of oil up to a reasonable operating temperature let alone keep it there. Wind Chill applies to engines as well as pilots, that what air-cooled means.

John Kerr
Hatz Classic/Rotec R3600-90+ hours
Logan UT