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Scott wrote: I get about 120mph at about 2400rpm. Scott, Here are a few thoughts. 1. To go 120 mph at 2400 rpm, you'd need a 52.8" pitch propeller with zero slip. There's always a few percent slip so I'd calculate that to do 120 mph at 2400 rpm, you probably would have to have a 54" pitch prop. I've never seen a 54" pitch prop on a Coupe but perhaps you have one. 2. If your prop isn't 54" pitch, you must have an inaccurate tach or airspeed indicator. Since you said you've checked your airspeed indicator, then either you have an inaccurate tach or you really DO have a 54" pitch prop AND have enough engine power to turn it to that speed. 3. You trip of 144 nm for 12 gallons. Lets see, 144 nm * 1.15 to get 165.6 statute miles. 166 statute miles / 120 mph = 1.38 hours. 12 gallons / 1.38 hours = 8.7 gallons/hour. That may be consistent with forcing an Ercoupe through the air at 120 mph. 4. As I mentioned in an earlier post, all airframes have a "natural" speed they can achieve with moderate power but to go faster takes a LOT MORE power and fuel. The Ercoupe's airframe has a "natural" speed of around 108-110 mph. If you push it through the air faster than that, it'll take a LOT more power and fuel. 5. If you slow down to 108 mph to improve your fuel mileage, you may not get it with a 54" pitch prop. I think you'd be better off changing to a flatter prop like the one called for in the O-200 STC (sorry I don't have the pitch handy to post). You'd have to accept a slower cruise speed but you'd climb a lot better. You'd also be able to cruise a LOT farther at a lower fuel burn than you're getting now. You'd be able to get good speed AND range by climbing high. With a transponder, you can easily climb to 11,500 or 12,500' and cruise both fast and economically. With the O-200, you'd get up there fast. 6. If you DON'T have a 54" pitch prop, we need to go through the numbers again because one of the numbers would be in error. Ed Burkhead http://edburkhead.com/ [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Thursday, January 30, 2003 12:21 PM To: [EMAIL PROTECTED] Subject: Re: [COUPERS-TECH] 0200 conversion Ed, Thanks for the advice. I used 12gal on 144nm by the reading on the gas pump. That was a calm wind trip too. But the 180nm is by 3/4 on the gauge. I checked my airpseed indicator and it is correct. I get about 120mph at about 2400rpm. On my long cross countrys I dont drink all that much. But also being as I am only 19, I have a pretty strong bladder. I flew a nonstop leg of 420nm once in a 172 and I was fine until I landed. Then it was a bee-line to the head. Thanks again Scott ========================================================================== ==== To leave this forum go to: http://ercoupers.com/lists.htm
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