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Permalink Reply by P. Richards on October 22, 2022 at 6:47pm

I don't remember the actual width of my Tri Z fuselage, but seem to remember it being 42 or 44 inches wide at the seats.

I'm 6 feet tall and around 200 lbs and had no problem flying comfortably with someone of equal size for several hours.

Things I can think of to look for:

-Check carefully around the engine mount to firewall bolts and the landing gear for any buckling in the skin. The 300 is a tough airplane but hard landings are hard landings.

-There was some flutter issues on some 300s when the aileron cables were not the correct tension. Make sure there is no slop in the ailerons.

- The bushings in the horizontal stabilizer do wear over time and require periodic replacement. Grab the tip of the stabilator and check for lateral play.

-Make sure there is clearance between the stabilator and the fuselage. Any screws or rivets that are loose can cause the stabilator to jam.

-Of course go over the logbook with a fine tooth comb to see what maintenance has been done and how often. A well kept aircraft will have a thicker log book that one that is poorly maintained.

-The engine is probably half the value of the aircraft. Look for maintenance records on the engine. Pull the spark plugs and look at their condition. Do a compression check. Get the oil analyzed.

There are lots of other things, but those are the ones that come to mind.

As for an AME, there are lots of them around, but one that specializes in Amateur built aircraft is better to have go over the aircraft. Someone who has built a 300 is a great resource as well.  If you are near Brampton, stop by the local EAA chapter there. Lots of guys have built and flown 300s from that airport.

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Permalink Reply by Harald Kriening on October 25, 2022 at 12:05pm

Hi P. Richards, thanks for your detailed info. The compression according to the logbook from a year ago shows

(72/77/76/68). The large spread concerns me. What do you think? Thanks 

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Permalink Reply by P. Richards on October 25, 2022 at 5:03pm

Harald, those compression numbers are fine for a half time engine. (Even for a low time engine actually)

Just by themselves they really done mean all that much. They mean more when compared to previous numbers, or current ones, And only after the engine has been run to operating temperature.

The days of having all the cylinders match and having the numbers real close to each other are long gone.

Tests prove that even an engine with all cylinders in the 60's will still develop rated horsepower.

What you don't want to see is a cylinder that is on a steady decline. It usually indicates something in the top end will need attention.

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Permalink Reply by Harald Kriening on October 26, 2022 at 2:12pm

Thanks. Good to know. I'll have a pre purchase inspection done and see if there are any changes. 

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Permalink Reply by James Stranks on November 9, 2022 at 4:03pm

Harold,

If you purchase that 300 and you get a builder's manual with it I would be very interested in a copy. I have the set of drawings but there are references to the manual and Zenair doesn't support this model anymore.

Thanks Jim

Owen Sound

3-306

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Permalink Reply by Harald Kriening on November 16, 2022 at 12:47pm

Hi Jim, sorry for the late response. Don't know if or when I will be looking at this aircraft. Possibly in the spring if still available.

Harald

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