Hatz Biplane Association

HI there folks,

So I'm starting to think seriously about engines. In general I've heard the O-320 is the choice for the classic, but some have used a 290 and get better range. I'd be interested to hear peoples thoughts and findings. What engine did you use? What would you do differently if you had to do it again?

Thanks for your thoughts and ideas.

Nick

Here are a few thoughts in no particular order...

Fuel burn - Several factors figure into this - power setting, leaning, prop pitch, Carb vs. fuel injection, aircraft configuration/weight. On a straight apples to apples comparison, I don't think the O-290 is so much better that it would make me go for it strictly on fuel burn.

Horsepower - I think I'd want as much HP as I could get given the draggy airplane we're building here. If I ever found myself in a tight spot where I need the ooompf to get out or over an obstacle I'd rather have the power.

Parts - not that the O-290 is bad, but the support for the O-320 is universal. If you ever were stuck somewhere you could be virtually guaranteed of getting a part (orobably true with the O-290, but you never know).

Fuel consumption - as we are experimental here don't discount other options such as electroic ignition and throtle body injection (i.e. Ellison). These would save on fuel consumption and allow you to run the O-320.

Personal endurance - I figure I"m good for three hours before needing a break. Going by the numbers for a classic... 28 gal fuel burning 8 gph (less with good leaning and) that would give me 3 hours plus a 30 minute reserve. Granted, that's cutting it close on fuel quantity, but the point is it's still decent range. Remember, it's a biplane... draggy, slow, not optimized for fuel efficiency.

I do a lot of long distance motorcycle touring, so I see a lot of similarities between the two. Three hours out of a tank of gas works well for me.

Doug summed it up pretty well but I would like to reinforce a couple of points. The 0-290 is going to be much more costly to maintain as parts are much more expensive and getting harder to find. The Hatz Classic is more robust than the CB-1 and you will need the extra Hp of the 0-320. The 0-360 is probably overkill on this airplane (my opinion). I find that about 2 hrs is enough in an open cockpit airplane, I use 3 as does Doug in closed cockpits, but 2 is about my limit with the airflow of an open cockpit. Throttled back, which you probably will be most of the time, your burn should be about 6 GPH w/the 0-320.

Hope this helps

Bill

I have a Classic with an 0320/150hp and I figure about 8 gal. per hour. With proper leaning I can sometime get down to about 7.5 gal. per hour. One thing that I found misleading is if you build your fuel tank according to the plans, you will end up with 23 gal. of fuel with about 22 gal. usable. I have talked with another builder who built according to plans and he has the same gallons available. When they talk about 28 gal. that was a tank that was built by Billy Dawson and it was tightly formed to the inside of the center section. I figure two hours of flying time with about an half hour reserve. That is all my bladder will take... Ron

I am just getting started on my Classic, but want to start educating myself on engine choices. Which versions of the O-320 work well and which ones do not? Also, which production airplanes used the desirable versions? Thanks for any input.

JD

Hi,
My project came with a O-320E2A which is from a 67 Cherokee 140. It is a wide deck with the carb central in the sump. I don't have the cowling done yet, but my mock-ups with cardboard sheet confirm that it will work well.
Al

How about a scratch built 0-360?
Do you want to see a first run video - Go to my face book - Michael McGrew
Michael
N838MM

Thanks very much, gents, for the detailed responses. That sure helps.

BTW, I finally have my Hatz up on her wheels! Sitting in that pilot seat the first time was a thrill!!

Nick