
Jun 12, 2003, 04:01 AM  
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[EFLT] Watts/Weight
This message from "Houfek,Jim" <houfekj@oclc.org> brought to you by EFLIGHT!
Recent discussions regarding how many watts it takes to fly a 5 pound ship reminded me that once upon a time someone had developed a table indicating various weights and the watts necessary to fly them..... Of course, the exact answer would depend on variables such as efficiency, etc.......but there were 3 ranges given for each weight. For example (these numbers are made up), for a weight of 3 pounds, the table would show 100150200 watts, where the first was for maintaining flight, the second for mild aerobatics, and the third for competition aerobatics. Does anyone know of such a table.......or alternatively, a formula that could be applied like this ?? Thanks..... Jim Houfek Columbus, OH *** Any complaints or problems? Send an email to monitor@ezonemag.com *** For help with list commands go to http://www.ezonemag.com/pages/mailhelp.htm *** For the list rules go to http://www.ezonemag.com/pages/mailrule.htm 


Jun 12, 2003, 04:01 AM  
n/a Posts

Re: [EFLT] Watts/Weight
This message from B12Boy@aol.com brought to you by EFLIGHT!
In a message dated 6/11/2003 2:13:06 PM Central Standard Time, houfekj@oclc.org writes: > Does anyone know of such a table.......or alternatively, a formula that > could be applied like this ?? > > Thanks..... > A table like this will always be vague and full of caveots. In general, you'de need a side table correcting for average flight speed, prop size, voltage used, ( more volts and less amps is more efficient and would need less watts), ect ect ect. It would get way to complicated and big to be very useful. This is why we have motocalc. ; ) motocalc.com Dean in Milwaukee  StripMime Report  processed MIME parts  multipart/alternative text/plain (text body  kept) text/html  *** Any complaints or problems? Send an email to monitor@ezonemag.com *** For help with list commands go to http://www.ezonemag.com/pages/mailhelp.htm *** For the list rules go to http://www.ezonemag.com/pages/mailrule.htm 


Jun 12, 2003, 04:01 AM  
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Re: [EFLT] Watts/Weight
This message from Doug Ingraham <dpi@rapidnet.com> brought to you by EFLIGHT!
On Wed, 11 Jun 2003, Houfek,Jim wrote: > Recent discussions regarding how many watts it takes to fly a 5 pound ship > reminded me that once upon a time someone had developed a table indicating > various weights and the watts necessary to fly them..... > Of course, the exact answer would depend on variables such as efficiency, > etc.......but there were 3 ranges given for each weight. For example (these > numbers are made up), for a weight of 3 pounds, the table would show > 100150200 watts, where the first was for maintaining flight, the second > for mild aerobatics, and the third for competition aerobatics. > Does anyone know of such a table.......or alternatively, a formula that > could be applied like this ?? The general rule of thumb is 50 watts per pound. I have a small speed 400 glider that will hold altitude on 18.7 watts into the motor. At this power level the S400 is about 60% efficient so the power to the prop is about 31 watts. The glider weighs 24 ounces so the power level to hold altitude in still air is 20 watts per pound. At 100 watts per pound you have a very aerobatic aircraft. Of course if you have something that has an excessive wing loading it might be difficult to manage but for typical models this rule of thumb works out pretty well. Doug Ingraham Rapid City, SD USA *** Any complaints or problems? Send an email to monitor@ezonemag.com *** For help with list commands go to http://www.ezonemag.com/pages/mailhelp.htm *** For the list rules go to http://www.ezonemag.com/pages/mailrule.htm 


Jun 13, 2003, 04:01 AM  
n/a Posts

Re: [EFLT] Watts/Weight
This message from FriarAHS@aol.com brought to you by EFLIGHT!
Matt Orme's "Motor Selection" as found under "Articles" on the Aveox website is comprehensible and is an easily applied "rule of thumb" concept. Alan (Alan H. Siegel, New York City)  StripMime Report  processed MIME parts  multipart/alternative text/plain (text body  kept) text/html  *** Any complaints or problems? Send an email to monitor@ezonemag.com *** For help with list commands go to http://www.ezonemag.com/pages/mailhelp.htm *** For the list rules go to http://www.ezonemag.com/pages/mailrule.htm 


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