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Rick, I have a 7146 pitched prop on my C-85. I can turn to redline (2575) in cruise if I want and normally cruise at 2400. At 2400 rpm, I get almost exactly (by ground reference measurements and gps) 100 mph. Possibilities for your reported numbers of max 2300 RPM and max speed of 80: 1. The RPM indicator could be off. You can get it checked at a lot of FBOs who have testers. 2. Your airspeed indicator might be off. Mine was off by 18 mph at cruise. (Thought I had a fast plane and wondered why I always had such head winds keeping me from getting there in the calculated time.) 3. He's not taking altitude into account when considering airspeed. As you get higher (measured by density altitude), the INDICATED airspeed gets lower even though the TRUE airspeed does not go down. RPMs DON'T go down with altitude. 4. Real engine or prop problems. After calibrating the RPM indicator, do a static run-up in still air. With my 7146 prop, I hit right at the maximum allowed static rpm of 2250. With a 7148, you should probably be between 2200 and 2250. If it's way lower (with a tested RPM indicator) then something's wrong with the engine or prop. Ed Burkhead Never forget: Osama bin Laden said he thought he could bring down the top third of two buildings holding 25,000 people each. He was trying to kill about 17,000 people who had nothing to do with his conflict! Definitions: Terrorists target innocent people who have nothing to do with their conflict. Soldiers, even guerrilla soldiers, target those who participate on the other side of the conflict. It's God's responsibility to forgive bin Laden. It's our responsibility to arrange the meeting. * United States Marine Corps * -----Original Message----- From: Rick Green [mailto:[EMAIL PROTECTED] Sent: Thursday, December 20, 2001 8:30 PM To: [EMAIL PROTECTED] Subject: [COUPERS] slow speeds --- ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- I've finally got a ferry pilot who is moving my 415D from So California to Michigan. He made it from Big Bear to 50 miles east of Albuquerque. He indicates that he is only getting 80 knots for performance. That's without a headwind. The plane has a 85 hp with a 7148 climb prop which was new in 95. He states that the engine is running strong, but does not turn over 2300 RPM. He believes that the prop may have been overpitched. any other ideas? There is a 48 hour window of good weather, but at this speed it doesnt look like he'll make it. Rick Green N93686 415 C South Haven MI ==^================================================================ This email was sent to: [EMAIL PROTECTED] EASY UNSUBSCRIBE click here: http://topica.com/u/?aVxiLm.aVzvvT Or send an email to: [EMAIL PROTECTED] T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================
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