Post by Andrew Rowland on Jun 10, 2012 16:02:06 GMT -5
For the second build in this pairing, i've chosen to lower the motor by 2mm rather than move it backwards. This means there is a 2mm vertical offset of pinion against the crown. The rear of this body is very narrow so will require a fsir amount of surgery. The front of this car (the lobster claw), also requires a lot of work if one is to try to model the space under the high mounted front wing. This I will work on soon but it has meant that in order to accomodate the guide inside the body it has to be mounted much further back than the other CF models i've so far built. This should again allow me to understand better basic chassis geometry theory prior to building my own....
Post by Alexis Gaitanis on Jun 11, 2012 12:36:32 GMT -5
Yes Andy, i was using Slot.it pinions 8,9,&10t and crowns,but i don't think the pinion size matters. You should also run-in the gears with toothpaste.I've also tried Ranch Design gears but the only thing i achieved was to chew them.
When you start to introduce large amounts of hypoid offset into straight cut gears, there are some tricks:
1. Larger crown gears work better than smaller ones as Alexis has said. 2. Also as Alexis says, the pinion size does not matter, but what can be done is to use a finer pitch pinion. For example, if the Crown gear is a 64DP then use a 72DP pinion. It gives a better mesh and less break-in time.
But, given that Slot.it gears are M50 pitch, there's not much to be done. I guess the Ranch Design gears are 64DP, so they could benefit from a 72DP pinion. I have done this with other aluminum gears (granted in much bigger sizes) and it has worked rather well.
Post by Andrew Rowland on Aug 5, 2012 16:32:29 GMT -5
So i've managed to squeeze a few hours of scratchbuilding - my first since the baby who is now a month old! Roll bar and front and rear wheel linkages plus the rear wing means this is now ready for undercoating.... Its starting to look like a car....
I have had great luck with offset gears and I think I was one of the first to try it in the 2008 VRAA. The trick is to use a plastic pinion that can deform a bit to match up with the crown gear. Here is a photo of my first VRAA chassis that won the championship well before Slot It made offset gears. I now use a combination of offset and motor tilt when I build a chassis. The farther the motor is ahead of the crown gear put more strain on the bushing in the endbell and the more deflection you get in the pinion shaft.
Post by Andrew Rowland on Aug 7, 2012 2:07:21 GMT -5
Moose, Ken isn't it? Sorry so many names that I forget!!
Thanks for that. You've confirmed what I was supposing hence my question to Alexis above. In fact i'm using the standard plastic Scaley pinions on the motors so hope that will give a soft sounding and non-gear chewing ride....
Post by Andrew Rowland on Aug 7, 2012 9:39:29 GMT -5
Well David, you ARE a pedant but as it happens a correct one! No idea how that 'B' snuck in there. It got posted along with the Surtees which I believe was a 'B' so maybe I got excited with my 'B's....