As Darryl Perkins suggested elsewhere, the amount of resistance required for the FLS will be different from the Bosches that are commonly used in FAI. The Bosch is nominally an 1100 Watt motor -- roughly the equivalent of 1 1/2 horsepower. According to Injoy, their standard motor which now replaces the 12V FLS is about 2.4 horsepower -- 1800 Watts. (and there are claims that it is actually stronger than the old stock 12V.) Their souped up replacement for the FLS is about 4 horsepower -- 3000 Watts.
If I understand what the FAI is doing by placing resistors in series with the motor is to compensate for relatively small differences between more or less similiar motors. The basic standard is that the motor must operate at no more than 1100 watts -- the product of the current across the motor and the amps through it may not exceed 1100 (watts). If a stock motor has more has more than 1100 watts input a resistor is placed in series with the motor. The added resistance reduces the current in the circuit and the voltage across the motor to an amount where the new (reduced) current times the resistance equals 1100. Thus a motor which is 5% overpowered (1155 watts) when placed in series with a resistor of approximately .003 ohms would have the product of the voltage across the motor times the current through the motor reduced to 1100 watts. (BTW these numbers are based on calculations which probably oversimplify this explanation -- the illustration is reasonably accurate in relative terms even if it is not on the money in absolute terms). A 1/8" dia steel rod, about 9.5 inches long would provide adequate resistance and would theoretically be required to dissipate less than 50 watts. On the other hand, reducing the stock Injoy motor to 1100 watts would require a .022 ohm resistor capable of dissipating over 500 watts of energy. This would require a 1/8" diameter steel rode nearly 6 feet long and would have an energy density (watts per foot) nearly twice as great as the FAI example given earlier -- the rod would get hotter. Reducing the hopped up Injoy motor to 1100 watts would require a .03 ohm resistor capable of dissipating nearly 2000 watts of energy. A 1/8" diameter rod nearly 8 1/2 feet long would be required and would have an energy density nearly 7 times greater than the FAI example -- the rod would get a lot hotter. Finally, reducing a stock Injoy motor to 1450 watts (half way between a strong stock FLS and an FAI motor would require a .01 ohm resistor capable of dissipating around 200 watts of energy. A 1/8" diameter rod about 2 1/2 feet long would have an energy density, again, about twice as great as the FAI example. At the very least it seems reasonable and feasible to tame the stock 12V FLS if people want to do it. Taming the souped up Injoy might be interesting to see (perhaps it will generate its own thermals :) . Finally, I have flown 8 or 10 flights off of the souped up Injoy (4 hp) with 300 lb line with a Supra Carbon Light. It's certainly not beyond the skills of most competition pilots to launch with this rig, but you better not screw up the timing between the tensioning and the toss. It is wicked strong. There is no doubt in my mind that it will not allow near the range of inattentiveness that a stock FLS will for someone launching an AVA and God help the nostalgia guy that doesn't really know his stuff when he steps up to this baby. In addition to the incrementally increased skill required to use this winch, there is little doubt in my mind that the strength of the plane being launched will be more material to the difference in ultimate launch height than current winches(can you spell universal carbon wings?). Its fine if everybody likes the stock 12V FLS, or even if the 4 hp Injoy becomes the new gold standard. But what do you think it would be like when someone comes up with a 6 or 8 hp winch with 450# line? It's got to stop somewhere. Think about it :) 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=789230 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
