iconnary
05-03-2008, 01:56 AM
I'm nearing completion on my new Spectra-G with a Hanson 260 3D Max. I've read numerous posts suggesting that the stock gear ratio on the Spectra (7.15) will have this motor running faster than it likes to be. A headspeed of 1800 rpm will have the motor running at 12,870 rpm, and I've read that the 260 is more comfortable at 12,500 rpm or less.
According to MinAir customer support, it is possible to get a different main gear for the Spectra-G that'll take it down to 6.69. This change will also of course require a new set of clutch doubler plates, which are also available according to MinAir customer support (not currently listed in their catalog though).
I then called up BH Hanson and spoke to Al Chianelli regarding this issue. His view is that there is nothing lost and plenty gained by running the 260 at 12,500 rpm or higher, provided you can keep it cool enough. His 260 3D-Max actually has a lighter piston than the 231, so vibration shouldn't be a factor either.
So at this point I'm just going to try running the heli with the existing 7.15 gear ratio all the way through break-in and see how I like it, and after that I may give the lower gear ratio a try. The only issue I can see with this is that I'm using Raja's clutch doubler plates in order to accommodate his generator, and they're sized for the 7.15 gear ratio (93 tooth main gear I believe).
I'm curious to hear other people's opinions and experiences with this heli/engine combination.
According to MinAir customer support, it is possible to get a different main gear for the Spectra-G that'll take it down to 6.69. This change will also of course require a new set of clutch doubler plates, which are also available according to MinAir customer support (not currently listed in their catalog though).
I then called up BH Hanson and spoke to Al Chianelli regarding this issue. His view is that there is nothing lost and plenty gained by running the 260 at 12,500 rpm or higher, provided you can keep it cool enough. His 260 3D-Max actually has a lighter piston than the 231, so vibration shouldn't be a factor either.
So at this point I'm just going to try running the heli with the existing 7.15 gear ratio all the way through break-in and see how I like it, and after that I may give the lower gear ratio a try. The only issue I can see with this is that I'm using Raja's clutch doubler plates in order to accommodate his generator, and they're sized for the 7.15 gear ratio (93 tooth main gear I believe).
I'm curious to hear other people's opinions and experiences with this heli/engine combination.