There is a penalty; as always there are factors that contribute to the overall effectiveness of the electrical link between servos and the RX.
I started out testing control surface excursions mainly to understand fidelity during very high speed descents while chasing an attempt at the FAI (F3B absolute) world speed record. As part of an ongoing program at the local university engineering dept., I conducted a series of tests whereby a position sensor was wired into a flap on A CF NYX. Deflection readings were measured during and many descents, mainly looking at the relationship of pitching moment and finding optimum TE reflex to neutralize stab position for minimum drag during this critical phase. It occurred to me that I could also perform the same tests on the winching and measure the same deflection during launch. This last aspect came about because (as some of you are aware) I was interested in minimizing uncommanded surface deflection during all aspects of flight. As I build wiring harnesses for some of you, it was only natural to experiment with lead MIL area (awg), cell-count, and what the losses were when sharing PWR/GND. I didn¡¯t need to perform real-world testing to know the results but I did anyways cause, given past history, I could count on folks balking at any suggestions to the contrary. To cut to the chase, yes, the (electrical) losses are significant enough to prevent the servos from holding, or recovering from, an uncommanded position after displacement during launch. This occurs to a lesser extent with the advent of digital servos, but the fact still remains that PWR to hold a commanded position, as far as what the motor sees, is still not adequate. For a typical F3x airframe, in order of importance, the most effective means of ensuring position fidelity¡as it relates to the electrical system: 1) 5cell NiCD (not NiMH) PWR supply 2) Digital servos 3) Dedicated PWR/GND from RX buss to motor 4) ¡Ý24awg 7 strand lead (circular MIL area of std 7 strand is offers only slightly less R than more expensive lead material w/higher strand count) Switch elimination/20awg leads from PWR source to RX buss. 5) Switch elimination/20awg leads from PWR source to RX buss. The estimates you ask about would be different for every installation. However, if you wish to get the best performance under the above conditions, then dedicated PWR/GND will hold a commanded servo position significantly better than when it is shared with two or more servos... Quoting Michael Lachowski <[EMAIL PROTECTED]>: > So what is the penalty to reducing the amount of wire on the power? Any > estimates on the penalty for doing things this way? > > [EMAIL PROTECTED] wrote: > > Just cause "it works" does not imply it functions as well as it could with > > > proper electrical connections. You think (wrongly...again) that this is > theory, > > why not do your homework (like I have), do some actual testing (like I > have), > > then get back to us. > > > > It never ceases to amaze me how folks can justify "success" without > something > > to measure it against. If we followed your analogy, we would still have > > buildings that were only a few stories high. > > > > What's the difference between NEXTEL and F1? Sound technological > advancement. > > > > > > > > > > Quoting "Donald B. Barker" <[EMAIL PROTECTED]>: > > > > > >>Go ahead and fly your theoretically correct wiring harness. I'll fly what > >>works. > >> > >>If a NASCAR racer were built using conventional theory, it would be so > >>overweight that it would not be competitive. > >> > >>don > >> > >>-----Original Message----- > >>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > >>Subject: Re: [RCSE] Carbon Supra #48 flies - weight < 61 oz ! > >> > >>Most(?) engineering solutions retain the integrity of the systems that are > > >>modified to achieve secondary goals. Increasing the series-resistance by > >>reducing the number of PWR/GND leads to the wing servos was taking a step > >>backwards. This shows up during launch... > >> > >>... > >> > >>Simon Van Leeuwen > >>PnP Systems - The E-Harness of Choice > >>Radius Systems > >>Cogito Ergo Zoom > >> > >>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 > >> > > > > > > > > Simon Van Leeuwen > > PnP Systems - The E-Harness of Choice > > Radius Systems > > Cogito Ergo Zoom > > > > 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
