My new Datum skis arrived, finally, not delay on the supplier, just the freightline, 9 days out of Quebec. Customs only cost a day, the rest of it was US time, must been a slow truck, meanwhile the snow is melting every day!

After buying these I had about 2 weeks to experience buyers remorse, I was really taking a lot on faith and a few pictures on a website, one of the more major purchases I've made with the least info but hey that's all part of flying I guess. My first look at the boxes they arrived in was reassuring, very heavy cardboard, with everything secured inside with foam, zero wear and tear and everything there.
I DID think they'd be bigger....

Oh, that was just the wheel penetration tail ski! Here's the main ski:these move the ski via a 12 VDC linear actuator and stragetically placed link arms, as the ski moves it rides into a wheel well that is molded in the top of the ski, this has the effect of securely engaging the ski/wheel junction, and also nicely streamlining the tire. When the opposite is done the ski is pulled up and the tire is exposed through the ski slot. He has been making these for 12 years, started off with ultralights and has now grown the design to up to 2500 lb gross planes. His big market is Europe, and he is supplying some of the big LSA builders there, as he is French Canadian, there was just a little confusion at times with the details (on my part concerning the dollar exchange rate, he got it right and I had to send another few hundred bucks, my bad) but all in all he did what he said when he said he would, nice when that happens.
These are the 2000 lb skis, and ought to provide mucho surface area for my 1300 lb gross/720 lb empty bird. I see the skegs on the bottom are skewed, I guess that provides something like toe-in on a car, helping things track straight ahead. From what I could tell from exhaustive research on websites etc, this designs seems to give some real life wheel options, and will be workable on more then smooth concrete. I was more worried about that then the ski action, I need to deal with my gravel driveway and turf runway along with the concrete hanger floor and deep snow
I am installing NOW, and should be testing mid week, snow is forecast for Tuesday! On a long breakfast flight yesterday, I flew over a lot of higher altitude sites that still had plenty, and just like when I got 26" Airstreaks (and learned to capitalize on what they could do) it really changes your perception on what is "good" terrain. In fact, the Bushwheels, once winter came and the deep snow, are the reason I felt the need for the skis:all of a sudden I was limited to airports, and all the sites I played on in the summer were now unreachable, with the skis I have them, and lots other, back.
Note the T-Craft spar saw horse legs, they were not airworthy anymore, but the have been great for other uses!

Thanks for putting this up.
Since the tire moves onto the ski and carries the weight to provide shock absorption and support when in the ski down position, an inner axle attachment is not needed. I like that design. It is the only experimental class ski that I found that does this. Rosti-Fernandez uses this principal too but I could never afford them. Can't wait to hear how they perform for you. Have fun.

Those look sweet Tom! You've seen Mike Wiley's install, yes?

BTW, I just picked up a "re-treaded" set of ABW's to try out. They are big - 29", but the plan is to fly them around a bit to "convince myself" that I need new ones, then sell these (which I got cheap) and my GY 26", and buy a new set. We'll see.

Look forward to some great ski pics!

You been down to see Joel at all?

I've stopped by Joels place a couple times now, it's right on my way to a lot of places I go to. Again, a GREAT setup!I installed some 6:00's to fit the skis, and the first time I pushed it out of the hanger (no skis. just the small tires) the difference in rolling resistance was substantial, it felt like the plane weighed 100 lbs less, BUT I've been running 3,5 lbs pressure. The drawback is when I pulled it back in a few hours later, the little bump getting into my hanger that the Bushies just glom on over, STOPPED the 6:00's. Got another day or so and then test fly!

Those skis look awesome, CG. I think this winter has few inches left in 'er still.

Great looking skis...so how much ?? and I love the sign in the window !

I've been looking at those for a while myself, looks like a good setup. I will be very interested to see how they hold up. I'll need the heavier model for my 2+2. It sucks when there's snow all around and none on my strip.
How rugged does the motor look?

Tim

The motor and entire linear actuator is an industrial type unit, a permanent magnet motor, and real torquey. I doubt I'll wear it out. Forty some hundred bucks depending on whether you get the tail wheel or not, and the exchange rate/ shipping etc. That's on top of my 2 K Airstreaks I bought last year, this explains why I drive a 600 dollar car (but it's a 4 wheel drive Toyota wagon with only 130 K miles and runs perfect), it's all about priorities
I have the axles at the machine shop getting bored for the axle inserts, that puts me at a stand still for a day or so. I have the breakers and switch mounted in the panel (the usual gymnastics getting to that black hole, to look at the finished job you'd think it took an hour or so, try damn near all day). Figuring where and how to enter the wiring from both sides took a while, I ended up drilling two good size hole in my glass boot cowl, sized to fit large rubber grommets that will stay there, in the winter the wire harness (2-conductor with a tough outer sheathing, I had it laying around from some other use) goes through a short length or rubber tubing where it goes through the grommet, then small hose clamps around the tubing are tightened just enough to keep the wiring located. Any electrical quick disconnect device would have been tough fitting through the grommet, so I just used crimp on fittings (not a spade type, but the type with about a 3/16" round hole) a small machine screw and nut, a little electrical tape, and 10 minutes or less when going from season to season installation was the keep it simple solution. The grommet hole with the wiring removed will be covered with a short AN-4 bolt with a fender washer, or maybe left open for some extra summer venting....
I also had to find a solid attach point for the front rigging, which required drilling 2 more holes in the boot cowl. Rather then just randomly butcher my boot cowl, I thought about it long and hard, for sure measure twice cut once applies here! I'm using a 4130 gusset that is already at the firewall, and a 5/16" bolt with a machined aluminum standoff to get the stainless bracket, that the cable and bungee go to, out a bit from the cowl. I needed to engineer the size and strength of the gusset, the load put on the bolt and standoff, and how the dynamics would work under load. Lacking the expertise to do that, I eyeballed it, and I feel pretty good about it:P Another several hours of hard work that looks like maybe an hours work when completed. You who have built your own planes know what I mean! In the summer the aluminum standoff bushing, which is 1 3/8" long, will be replaced by a shorter one, just long enough to fill the hole in the glass boot cowl but not stick out in the airstream. The rear cable attach points were easier, using existing bushings in the airframe and the lift strut attach bolt, which I replaced with a slightly longer one. I'll post a few pictures when I get my axles back.

glaciercub wrote:Great looking skis...so how much ?? and I love the sign in the window !