---------------------------------------------------------- Commander-List Digest Archive --- Total Messages Posted Sat 08/20/11: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:42 AM - Re: Slow flying, extended range and fuel consumption. (BobsV35B@aol.com) 2. 12:17 PM - Fw: Attention- Emergency Honeywell AD for Twin Commander Operators (yourtcfg@aol.com) ________________________________ Message 1 _____________________________________ Time: 07:42:18 AM PST US From: BobsV35B@aol.com Subject: Re: Commander-List: Slow flying, extended range and fuel consumption. Good Morning Adam, Just looking at some old posts and spotted this one. I do not recall any comments so here is mine. Your airplane will require the least amount of fuel to go one mile if it is flown at the Best Lift over Drag speed as shown on the indicator. That is IAS, not TAS. I do not have relevant data for the Commander but I am confident that 90 knots is too slow. My Beech V35B gets best L/D at about 106 knots when at gross weight. That speed will decrease as weight is decreased. Since an early Commander has speeds comparable to my V35B, I would WAG that a 520 would have similar speeds. The newer and heavier Commanders would undoubtedly have a higher Best L/D speed. That speed works at all altitudes. Way up high, you can get a pretty good True Airspeed at the low Indicated Airspeed, but the miles per gallon will be the same at all altitudes. Air Carrier aircraft generally try to cruise at a small percentage faster than Best L/D to provide better speed stability and to compensate for small speed excursions. The penalty for going too fast is small while the inefficiency rises quite rapidly when going too slow. Back when I was a gainfully employed aviator, we generally tried to fly at about 105 per cent of best L/D. The increase in drag curve is rather flat at first, but the drag goes up quite rapidly when you get more than twenty to thirty percent above best L/D. For an airplane with a best L/D speed of 106, I find that 120 knots indicated still provides very close to optimum. 130 is nice with little loss, and 140 still works, but is starting to noticeably decrease the range. Consequently, I choose my cruising airspeed by analyzing the range I want along with the time constraints of the mission. My default indicated airspeed is 140 knots. For my airplane, that is a nice ball park number. At FL250 that is a true airspeed of 210 knots. At sea level, it is only 140 knots, but the miles per gallon in a no wind condition are very close to being the same. Obviously there are a lot of variables that I have not mentioned, but good economy of fuel used can be found by flying slightly faster than best L/D. Most of us will also want to consider the value of time when planning any individual flight. I hope this has given you a place to start when figuring how fast you wish to fly your Commander. Happy Skies, Old Bob AKA Bob Siegfried Downers Grove, Illinois Haven't flown a Commander in at least fifty years, but I liked them when I was flying them . In a message dated 8/5/2011 10:46:50 P.M. Central Daylight Time, adam@adamfrisch.com writes: --> Commander-List message posted by: "stratobee" Has anyone, just for kicks, explored the real low end spectrum of slow flying and the fuel consumption there? My aircraft is in for her annual so In haven't been able to try yet, but I will. I want to see what 70-90kts cruise at altitude would give in fuel consumption. Has anyone tried? Be fun to see just how far you could get if you're not in a hurry. -------- Adam ________________________________ Message 2 _____________________________________ Time: 12:17:13 PM PST US Subject: Commander-List: Fwd: Attention- Emergency Honeywell AD for Twin Commander Operators From: yourtcfg@aol.com -----Original Message----- From: Aero Air Sent: Fri, Aug 19, 2011 3:49 pm Subject: Attention- Emergency Honeywell AD for Twin Commander Operators Aero Air LLC Important information Newly released Emergency Airworthiness Directive 2011-15-51 Earlier this week the FAA released Emergency Airworthiness Directive 2011-1 5-51. This AD covers all models of the Honeywell TPE-331 engines that may h ave a PMA=99d main shaft bearing, part number (P/N) 3108098-1WD, manu factured by Dixie Aerospace, LLC, installed in the engine. The AD indicates the bearings were manufactured with inadequate inner ring guide flange clearance. The AD also indicates that the bearing failure mech anism is severe and sudden and if not corrected, could result in engine mai n rotor seizure resulting in engine damage, shutdown, and damage to the air plane. This AD requires an inspection of records to determine if a Dixie Aerospace , LLC main shaft bearing, P/N 3108098-1WD, is your TPE331 engines. Within 10 operating hours, affected bearings must be removed from service. If you have any questions regarding this AD, need logbook research or have a suspect bearing in your engine, please call us at Aero Air. For a copy of the actual AD, please click the "Learn More" button below. Aero Air LLC 2050 NE 25th Ave. Hillsboro, OR (800) 448-2376 www.AeroAir.com This message was sent to N700PF@aol.com from: Aero Air | 2050 NE 25th Ave. | Hillsboro, OR 97124 Email Marketing by Unsubscribe ward To a Friend -----Original Message----- From: Aero Air Sent: Fri, Aug 19, 2011 3:49 pm Subject: Attention- Emergency Honeywell AD for Twin Commander Operators Aero Air LLC Important information Newly released Emergency Airworthiness Directive 2011-15-51 Earlier this week the FAA released Emergency Airworthiness Directive 2011-1 5-51. This AD covers all models of the Honeywell TPE-331 engines that may h ave a PMA=99d main shaft bearing, part number (P/N) 3108098-1WD, manu factured by Dixie Aerospace, LLC, installed in the engine. The AD indicates the bearings were manufactured with inadequate inner ring guide flange clearance. The AD also indicates that the bearing failure mech anism is severe and sudden and if not corrected, could result in engine mai n rotor seizure resulting in engine damage, shutdown, and damage to the air plane. This AD requires an inspection of records to determine if a Dixie Aerospace , LLC main shaft bearing, P/N 3108098-1WD, is your TPE331 engines. Within 10 operating hours, affected bearings must be removed from service. If you have any questions regarding this AD, need logbook research or have a suspect bearing in your engine, please call us at Aero Air. For a copy of the actual AD, please click the "Learn More" button below. Aero Air LLC 2050 NE 25th Ave. Hillsboro, OR (800) 448-2376 www.AeroAir.com This message was sent to N700PF@aol.com from: Aero Air | 2050 NE 25th Ave. | Hillsboro, OR 97124 Email Marketing by Unsubscribe ward To a Friend ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message commander-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Commander-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/commander-list Browse Digests http://www.matronics.com/digest/commander-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.