Saturday, January 7, 2017

Skiis, Hardpoint and Stabilization Success


Got out and up yesterday. Cold 30 deg in the sun, calm with mild variable gusts. It was time to test the skiis, the newly revised wing hardpoint and the stabilization system on the 10cc BigbStik.


A light snow in the morning, but most of the deeper snow has melted off. At this side it's shallow with grass poking through, on the far side about 6". I walked across to fly from the other side as is my new preferred side. It's that hard to walk on iced over snow




The new hardpoint addition. I redid the post on the wing, and added this extra piece to secure the anterior edge of the wing. That wing post hard point takes a lot of forces and I didn't want to depend on it alone. Worked perfectly, even in wind and aerobatics.



Wing attached. You can see how the wings snugs up under that new piece.



Today's tarmac. Using the wing bag to kneel on, trying not to make footholds in front of the plane so it can slide out for takeoff.

One of the issues with the skiis is that they offer virtually no resistance to thrust, so even at idle the plane wants to scoot off at high speed. This also makes roll out after landing a bare knuckler. This was a problem today. I gave it some thought when I got home and decided to use some of the L-rod I have for making vortex fences and CA'd some Vs to create a little resistance.


Tail ski. The hollow hardpoint twists against the Shea of being used as a tail wheel, so I filled it with epoxy.



Mains. Trying one set each side.



In flying with the skiis for the first time she flew a bit tail heavy, and there is a bit more drag. I pulled the few oz of weights off the tail and will recheck CG. I didn't do a CG check before this flight, which I realize was a mistake I got away with. Clearly the tail ski is heavier than the tail wheel.

Also on my last flight I toggled the stabilization system with the mechanics gloves I fly with in the cold. I use the F-mode switch on my DX8-orig, right above the ignition kill switch, left side. My finger usually rests between the switches, but with the gloves I have to keep my finger below the kill switch. To toggle the stabilization system I simply slide my finger up (on) or lift it over the switch and pull it down (off). Yup. Killed the ignition mid turn in a tail wind 10 feet AGL. Landed fine but in the middle of footprints in the snow without any slowing (skiis remember) so she was still shooting across the ground and she eventually tipped. That snapped the ceramic top off the spark plug which hangs under the cylinder which hangs under the nose, which was probably quite brittle and cold, despite the engine heat.

I had tried not using a gasket on the muffler header. It sprayed post combustion oil all over the place aft of and around the header. Got some gasket material today and will cut a gasket for it today. Back when I replaced the cylinder I noticed that there isn't a gasket between the cylinder and the engine block... I wonder if that is where some or all of this oil is coming from?

Replaced the spark, made the "ski draggers", new gasket. Waaaaay too cold today with heavy snow, but maybe tomorrow we fly.