J2Ski Forum Posts and Replies by Dave Mac

Duelling again Tony?

Idavies wrote:

Dave Mac: where did you get accom after all? L.

With Herbert at the Harf. It's a great ski-in/out location, but the beginners will need to walk down to the village or catch the ski-bus. It's also close to my second home, the Bichlwirt.

We are planning a trip to the Schiwelt, since Hopfgarten is only 10 minutes away from Grafenweg. And much as I don't go up to Auffach that much, for sure a couple of our group like it a lot.

We met with old instructors, Sepp, Tony Niedererfriniger, Hansi Dummer, and Konrad Gwigner, when we were there in July. Also, I gave a water-colour painting, (view of Oberau church and Kellerwirt), to an Oberau friend, Hans Gruber, ~ he plays music with another guy, all over the Wildschoneau, but quite often in the Bichlwirt.

I need to contact Sepp Schellhorn or someone to get the lessons organised, do you know what date the ski school opens?

Tony-H wrote:

Apologies for sounding like a plane nerd.

Tony, I think you'll find the spelling is "plain" nerd. :lol:

Forgot to say, great picture, beautiful technique. I'm not a carving fan, but when it's done as well as that .....

Trencher, I don't know if you're going to enjoy this, I'm sure that some people will lose the will to live. I think I have the following right, but if anyone can do better, let us here it.

Firstly, I don't know what a riser is, but from what you say, it must raise the fulcrum that the boot operates on.

So here goes. I am using my body measurements, but they will ratio to other heights. I am 6' 2" tall.

Data & Assumptions:

For skiing dynamics, the body momentum passes through at the metacentric height. On the human body, the MH is at the centre of the chest. Height to my solar plexus is 1400mm. With a riser, MH would be 1425.

Height to centre of my knee, with boots on is 575mm. With a riser, knee height is 600.

So you hit a bump, the body momentum (F) is forward, there is an opposite force (f) on the knee.

So without a riser, we have F1 and f1. With a riser, we have F2 and f2.

Using the principle of leverages,

No riser, 1400 x F1 = 575 x f1, With riser, 1425 x F2 = 600 x f2

So, F1 = (575/1400) x f1 and F2 = (600/1425) x f2

but F1 = F2

Hence (575/1400) x f1 = (600/1425) x f2

And, change in knee force f2/f1 = (575/1400)/(600/1425)

= 0.975

This indicates that in the riser condition, there is 2.5% less force on the knee.

It may be that the fulcrum should be measured from the bottom of the ski. (I'm not going to do that, I am already in my dressing gown, wearing ski boots and a tape measure, desperately hoping that my OH doesn't come into the room.)

However, in that case, the force on the knee would be even less.

It may also be that in using a riser, the fulcrum remains as the base of the boot, actually at the toepoint. In which case, there would be no change in knee leverage.

Simple innit?

You are right to be cautious Adele, but this stresses the importance of paying for flights with a credit card, not a debit card. Adds about £4 to £8 per ticket, but good insurance.

That's a good early start, Jan.

Will be in Niederau, 27 December for New Year week, and also for last two weeks in Jan. Almost certainly another one to two weeks in March.

Just trying to fit in another "biggie" off the hit list. May be St Anton in late Feb. Will let my OH decide where. She can decide anything she likes as long as I get to skialot.

It's going to be another great winter.

You won't need a guide for Niederau.