1st2fly Wrote: > And for the real purists that don't want to sully their models with an > installed power system, a standard power pod could be attached via the > > normal tow hook, which would drop off at the end of the power run and > be > recovered via it's own little chute by a runner, etc. That way, you > don't > have the drag and weight of the power system to lug around during the > soaring part of the flight. Again, each such power pod would be > restricted > to a specific motor/prop/battery combo with a timer cutoff switch (you > could > use one of the switches the FF people use). > > Just think of all the winch and retriever related issues that would > disappear! A club hosting a TD event using this launch method would > not > need to deal with the logistics and expense of winches, retrievers, > batteries, chargers, and people to run them and maintain them. AND it > would > open up more fields that could be used that previously would have been > > considered too small for a TD event or not aligned into the most common > > prevailing winds, etc. And I'm sure there are many out there that > could > point out such a field that would be closer and more convenient to many > club > members in towns everywhere. Everyone could easily build such a power > pod > and for very little expense, if one of the more common and inexpensive > > outrunner motors were used. The only option allowed would be the type > of > battery used, as long as it's voltage output was restricted to a given > > value. The really competitive among us of course would try to build > the > lightest molded power pod with the smallest, lightest battery and ESC > (and > even that would be optional because with a timed cutoff, you don't need > > anything except full power - on or off - so an ESC is not required). > > I think that powered launch TD is a very, very valid idea! > > Keith > > > > -------------------------------------------------- > From: "1st2fly" <[EMAIL PROTECTED]> > Sent: Saturday, June 28, 2008 9:57 AM > To: <[EMAIL PROTECTED]>; <[email protected]> > Subject: Re: [RCSE] Re: Gordy- Logic without limits.....or I couild hae > read > the article in context:-) > > Seems to me there is a simple solution.... To use motors in place of > winches and make it an even playing field, just simply require the use > of > only one specific make and model of motor, prop and battery pack so > that > everyone has exactly the same power system (like using the same winch) > AND > use a time-programmable battery cutout switch so that everyone gets the > same > motor run time. The cool thing about doing this is that it brings new > meaning to Man-On-Man competition, because so many gliders could be > launched > all at the same time into the same air, especially if everyone were > using > 2.4 systems! > > Of course, LANDINGS would be interesting..... hmmmm... 20 or 30 gliders > all > making close to their time and all trying to land at the same > time..... > > Obviously, the number of gliders launched at any one time would be > limited > by the number of landing tapes, etc., but at least you would not have > to > worry much about field layout with regard to winch lines, and for the > same > reason, wind direction wouldn't be as much of a factor, either. > Contests > could be run out of much smaller fields without the need to > accommodate > winches and lines. > > Keith > > -------------------------------------------------- > From: "Lincoln Ross" <[EMAIL PROTECTED]> > Sent: Saturday, June 28, 2008 6:50 AM > To: <[email protected]> > Subject: [RCSE] Re: Gordy- Logic without limits.....or I couild hae > read the > article in context:-) > > Just read the article. To some extent, I find myself agreeing (did I > write that? pass the Risperdal!). However, just because Gordy and I > succumb to tempatation when we have an electric glider* that is > getting > low, doesn't mean other people do. If you have the strength of will to > ignore that nice power switch after the first climb is over, you can > ignore what he said. But I'll admit that when there's a motor in the > glider I usually won't fight out the last 50 or maybe even 100 feet. > And > I definitely will with an unpowered glider. So there go all those fun > saves. (I was told that on a 58 minute flight (or was it the 60 > minute > flight??) I was down to 20 feet at 3 minutes. I thought it was 40, but > that's another story. Low enough with a 25 year old 2 meter. (hmm... > is > this the Gordy bragging disease too?) > > We have a bunch of people flying electric gliders in our club. Some of > them even come home with vinyl/brass/particle board plaques sometimes. > Some of them have houses in structural overload from hanging the > plaques > on the wall. However, we also have a guy who is trying to start an > electric event which involves old hlg's and vertical climbs. He very > seldom talks about the power off part of the flight. This guy has > acquired my old Chrysalis. It's very amusing to watch him launch, but > it > ain't soaring. He can get lots of exciting vertical drag racing > because > the flights don't last long. The model is, I think, two or three > ounces > overweight, which is a lot on a Chrysalis. > > Anyway, Gordy mentions an automatic motor shutoff. I think this will > emphasize motor power even more, because now you have to be going Mach > 0.5 at motor shutoff so you can get another 1000 feet or so. Therefore > it needs to link in to activate flaps or spoilers for 5 seconds or > something. (Perhaps activate spoilers for first 30 seconds of flight > above 500 feet? Total energy probe?) Once these little details are > worked out, I don't see why Gordy shouldn't then advocate using a > similar system with a releasable towhook on winch launches. That'll > make > Histarter happy too. (for those of you who don't know my last > reference, > your ignorance is bliss) > > > *Sailplanes are for people with bigger egos than mine. Gliders can go > up > to, including, sometimes, 40 size power trainers that happen to be > dead > stick. > > >Gordy wrote: > > > >Or you could have posted me directly to discuss it such a fun topic > :-) > >Its been quite a while since I wrote that article which is more a > review > >of > >the programmable altitude priority motor cut off switch....but I play > this > >game :-) > > > >The context of the article is replacing winch launches.. > > > snip > > >One more time because I know that motor heads who have found a > sailplane > >will fit motors will want to go off on how what they do is good (and > it IS > >by > >the way) but that has nothing to do with the context of the > >article...replacing > >winch launches with electric motor launches. > > > >So with a programmable altitude shut off switch, TD pilots could have > the > >smallest and cheapest possible motor/prop/gearbox/controller/ > battery, > >versus > >electric sailplane events where the motor package is priority. > > > > > snip > RCSE-List facilities provided by Model Airplane News. Send "subscribe" > and > "unsubscribe" requests to [EMAIL PROTECTED] Please note > that > subscribe and unsubscribe messages must be sent in text only format > with > MIME turned off. Email sent from web based email such as Hotmail and > AOL > are generally NOT in text format > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" > and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > > subscribe and unsubscribe messages must be sent in text only format > with > MIME turned off. Email sent from web based email such as Hotmail and > AOL > are generally NOT in text format > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" > and "unsubscribe" requests to [EMAIL PROTECTED] Please note > that subscribe and unsubscribe messages must be sent in text only format > with MIME turned off. Email sent from web based email such as Hotmail > and AOL are generally NOT in text format
Actually, by using an altitude limiting device as the _primary_ means of regulating launch height, there are secondary limits (watt limitations, etc.) which can easily be incorporated which do not really have to be particularly precise to keep the max. differential (overrun) on launches well within the range of the impact of timing errors (less than 20 feet). This still requires a confirmation that the altitude limiting devices which are used are uniform enough to get the primary job done. It may take a little creative thought on the part of everyone, but it is highly likely that a simple and relatively inexpensive system can be devised which will adequately emulate our TD flying without requiring a "one-design" power supply. (If you are an insomniac, I have furnished a summary of some calculations in pdf format in the RCSE electric soaring forum. Happy Landings, Don -- dharban ------------------------------------------------------------------------ dharban's Profile: http://www.rcgroups.com/forums/member.php?u=31927 View this thread: http://www.rcgroups.com/forums/showthread.php?t=886133 RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
