yep 20 years ago a winch launch took 1/3 litre per winch but the old holden ute used 1 litre per winch and this was very accurate time after time Ian mcphee
2009/10/30 Todd Sandercock <todd_soar...@yahoo.com.au> > A winch would have to be the most efficient for sure. Would be interesting > to work out how much better it is than a tow plane though. > Does anyone have any figures on the fuel consumption of a winch?? > > Todd > > ------------------------------ > *From:* Mike Cleaver <wom...@netspeed.com.au> > *To:* Discussion of issues relating to Soaring in Australia. < > aus-soaring@lists.internode.on.net> > *Sent:* Fri, 30 October, 2009 9:42:39 PM > *Subject:* Re: [Aus-soaring] Electric tugs (was "applying skills to > another activity") > > At 18:07 30/10/2009, Morgan wrote: > > > Yes, but an electric tug doesn’t have to carry the equivalent of 100L of > avgas like a “conventional” electric aircraft would for cross-country > flying. If you allowed regenerative battery charging, the tug could > completely exhaust its battery getting to 3000ft and then recharge just > enough on the way down to allow for a go-around or hold. The battery + > motor should weigh much less than a 6-cylinder Lycoming. > > > > > Taras has built a scale model prototype - 40% regenerative efficiency. > 75W electric power to fly level. > > > > The airfoil section on the prop must be symmetrical to work as both a > windmill and a propeller. (The next time you meet an aerobatic pilot > droning on about symmetric airfoils, ask him what airfoil is on his prop.) > For the best efficiency as a windmill, the prop needs to have a large > diameter and the delta-V (change in velocity along a streamline) needs to be > minimised, indicating that a descent at close to minimum-sink speed would be > required for maximum energy recovery. > > > Todd (no relation) said: > > This is the completely wrong thing to be putting the electric motor in. > The tug is the problem not the solution. Its the GLIDER that needs to be > electric!! > > All this makes me wonder why we are talking about lifting either the > Internal Combustion engine or the batteries into the air if we are really > interested in energy-saving. > > Surely a winch is the most sensible area to use an electric motor to launch > a sailplane, where you can have as much weight and do not need to > shock-proof the charging system because they stay fixed on the ground and > the charging system can be remote from the winch cable driving mechanism. > > That's why we can have diesel winches that are so cheap to run, though they > can't do outlanding retrieves or launch to a remote start point like a tug > can. > > Incidentally, aerobatic pilots (and they are competing at Temora this > weekend) may have symmetrical wing sections to fly inverted - but the > propeller does not need this in-built handicap unless it is intended to use > it as an in-flight brake, or to both push and pull the aircraft (which would > involve also changing the direction of rotation, or at least a significant > reversal of pitch past the full-fine point to be able to drive the airframe > tail-first). > > Wombat > > _______________________________________________ > Aus-soaring mailing list > Aus-soaring@lists.internode.on.net > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring > > ------------------------------ > Get more done like never before with Yahoo!7 Mail. Learn > more<http://au.rd.yahoo.com/mail/launch09/tagline/*http://us.lrd.yahoo.com/_ylc=X3oDMTFnY201cHJnBHRtX2RtZWNoA1RleHQgTGluawR0bV9sbmsDVTExMDQ3NjAEdG1fbmV0A1lhaG9vIQ--/SIG=11aljvgo4/*http%3A//au.overview.mail.yahoo.com/> > . > > _______________________________________________ > Aus-soaring mailing list > Aus-soaring@lists.internode.on.net > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring >
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