I’d prefer more legroom!Quite a bit lighter. I''ve seen a figure of 350 lbs. For a model A without the bell housing etc. Not sure if that includes flywheel. Piets are often flown with Corvair engines. Those are over 200 lbs. With a VW it might need a longer motor mount.
It's about 3 feet from the front seatback to the firewall already. How much legroom do you need, and won't you be flying from the back anyway? I suppose you could move both people forward a bit to make up for the light engine. How does one see where you're going when turning a Pietenpol? Doesn't the wing really get in the way?I’d prefer more legroom!
If my legs are flat on the ground with my back on a wall, I would require 4‘ 3“, but as the legs are bent a bit I spoke that 3‘ 10“ would be about fine.It's about 3 feet from the front seatback to the firewall already. How much legroom do you need, and won't you be flying from the back anyway?
Even if this one goes with its precision into the world of a child, I’d like to build a cnc router out of wood.This is an interesting CNC machine (only $350) that might work for this project...
The figuring out isn't so hard but the hardware to make it ridged will make it more expensive. Feedback servo rather than stepper would help.Maybe someone really clever will figure out how to make it accurate. Maybe some kind of optical feedback?
No matter what you build you will want more accuracy in harder/stiffer materials. Wood routers can work for wood and light cuts in aluminum. 4x8' requires something other than ball screws for the 8' direction so it gets a little more tricky. Belts can work. There is nothing magic about building a CNC router out of wood. It is just limited by its stiffness. All of the bearings and linear rails are pretty cheap and available on ebay.Even if this one goes with its precision into the world of a child, I’d like to build a cnc router out of wood.
The size I’d like to build my self is 8x4, so big enough to work on standard size sheets.
So far I haven’t found a gantry cnc router made out of wood, that is firm and sturdy enough, that looks like it could withstand solid wood working.
there is at least one professional built series of wooden cnc routers:
it doesn’t have to look this good, but the direction, as it looks really solid to me.
such a beast would for sure enhance the precision to build any kind of wooden airplanes even a Volksplane :gig:
I think part of the point of feedback would be to reduce the required rigidity.The figuring out isn't so hard but the hardware to make it ridged will make it more expensive. Feedback servo rather than stepper would help.
I'm kind of surprised that no one has built a single arm router with software to convert G-code to polar coordinates. Such a hobby CNC would still have rigidity problems but would be super simple to build and compact to store.
Probably correct. :cry:You can't send corrections back to the stepper/servo fast enough to make up for how incredibility slowly and unpredictably the flexible cable can handle those correction.
There's room for some clever guy to make it work but we've been playing with these things for years and nobody has come up with a reasonable way (so far) to handle the necessary forces with flexible cables. Using a polargraph to control a router dates back to, at least, the day after the first Ardiuno hit the market and probably goes back a century or two before that. ...you can make a hammer drive a screw but you'd just be making a f@^%ed up screw driver....Solutions:
That's the "Magic Feedback System" I mentioned in post #157