Zenith Aircraft Builders and Flyers
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Reasonable Airspeed????
Plane was light with only me and about 10 gallons of fuel. Ambient temperature about 70*F.
Before the changes mentioned above, 5,500 RPM gave about 85mph.
There is no static port on the airframe, so the Alt and A/S vent in the cockpit behind the panel.
Replies to This Discussion
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Permalink Reply by Bert Shivers on
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I tried, but failed to attach a photo. It showed level flight, 5,300 RPM, 93mph.
Not a particularly sleek 701, even as 701s go.
I think the WOT rpm is 5500. Months ago adjusted the prop pitch so the engine would not over-speed in level flight. I need to check that.
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Permalink Reply by Jim and Amelia Isaacs on
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Hi Bert. Yeah conventional wisdom is set the prop itch to achieve 5,500 rpm WOT level flight at one’s typical cruise altitude. How did the rudder adjustment go?
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Permalink Reply by Bob McDonald on
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Advice on WOT throttle @ 5500 rpm is right on the money. CH701 cruise is 85 mph, and CH750 is 95 mph. Above those airspeeds the airframe just makes more noise and you burn more fuel.
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One post script - if it makes sense, adjust your prop to your particular situation. I am an example- my home field is a short field and a confined area, so my prop is pitched to 5500 RPM @ WOT on the ground with brakes locked- I need the power to clear the trees after I leave the ground. The tradeoff is I need to pay attention to my RPM after I clear the trees and lower the nose. It helps that the 701 is so draggy- airspeed- and thus RPM- builds slowly.
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Permalink Reply by Jerry Griego
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I set my my WOT at 5800. My EIS turns a red light on at 5750. I live a 5000 ft. AGL and DA is usually 6100. 300 RPM is a lot of power not to have when you need it. Rotax in Austria run the 912 series of engines at the plant at 6200 RPM for an hour and they hold out just fine. Rotax wants us to baby our engines at no more than 5800. A family member friend worked at the Austria plant for 9 years before moving to Spain. His Job was to run the Hell out of them. so If you go above 5800 for 15 seconds your not going to blow it up. You won't find this information in any magazine article. I do believe in 5500 for level cruise flying.. I thought I would share this.
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Permalink Reply by Mel Asberry
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You live 5000' AGL? Love to see your house.
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Good catch Mel. That's funny as hell. Your a pilot you know what I mean.
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