Hi there,
cheers again from Italy.

Yesterday the blokart of Alessandro "Gassa" reached 75.4 kph on a flat surface - our "little Ivanpah" - in Sardinia, one of the main islands, together with Sicily, in Italy. The blokart was naked (no pod) with a 4 squared meters sail . The wind was about 30 kn, with gusts at 40 kn. Actually, the pilot was so oversailed that just after the record, sailing on free wind, a gust made him capsize. Well, the blokart needs some fix... the pilot is ok. Some pics on www.spazioforum.it/forums/tractionkite-about795-0-asc-0.html. On the same spot we're going to have a meeting on September. Now the challenge is on, so I'm thinking about some modifications to my Seagull MC.

Now my questions are:

- Don't you find pretty boring that FISLY has only an "unlimited" landspeed record? Wouldn't be better, interesting, challenging and funny to have different classes?

- A technical question. I've followed the Greenbird issue and I find one of the most interesting detail of the thing is the downforce generated from the upwind axle. Do you believe that at high speeds having mobile surfaces on the trailing edge of the axel - a sort of ailerons, differential, generating lift on the downwind wheel and downforce on the upwind wheel - could be an efficient way to prevent the yacht from tipping over at a very low cost in terms of drag? Silly question?

Thank you, cheers

Enrico

- A technical question. I've followed the Greenbird issue and I find one of the most interesting detail of the thing is the downforce generated from the upwind axle. Do you believe that at high speeds having mobile surfaces on the trailing edge of the axel - a sort of ailerons, differential, generating lift on the downwind wheel and downforce on the upwind wheel - could be an efficient way to prevent the yacht from tipping over at a very low cost in terms of drag? Silly question?

About a year or so ago when Greenbird was doing its thing I had similar thoughts, the conclusion I came up with was for a yacht of approx 2m wide (outside) class5 size by the time you take off the width of the wheels, seat and wing controls the size of each wing would be approx 500mm wide by 200-300mm deep, the whole set up may add 5kg to a yacht and would really only come into best effect at high speed 40+km/h, but yachts seem to get more stable at these speeds anyway and would the additional weight be counteracted by aerodynamic smoothness be worth it? A wing over the front wheel giving downforce might be good though.

BUT for a big yacht it would be interesing to try

Does anyone have acess to or want to build a wind tunnel

Something like this. In my opinion it could work only at high speed and with a very wide axle to avoid turbulences from the hull.



As regards the weight, well, I just don't know. Must a pure record breaker be light or heavy? I don't know the weight of the Greenbird, the Ironduck it's not a feather and Millett Denning didn't care at all! Coronations were sheer heavy metal. Strange things happens when we're talking about speed record. The flight speed record of the racer Macchi MC 72 lasted 55 years (I'm talking about prop single engine aircraft) despite it was a seaplane. And it was a seaplane mainly because it needed an endless surface to get speed and take off.

@ test pilot 1 In those speed trials did you sail the same yacht you usually sail for fun or in a regatta? Wouldn't be nice and challenging to have, for instance, an international Class 1 for landspeed record with a maximum weight up to 40 kilos, and see a Potty! or a Ludic with a tiny wing sail and the pilot dressed like a superhero? I absolutely don't want to collect a megabudget and spend 10 years of my life to put my name after Bob Schumacher and Richard Jenkins! Give me a chanche with a smaller size!

Cheers - Enrico

sn said...

veladaterra said...
the pilot dressed like a superhero?

Cheers - Enrico

where has that photo of landyacht in his lycra suit gone?

I would do a new one , but its a tad chilly outside
on the blokart speed bit, youve just about got to the realistic max for an uncovered blowie.
The really dedicated blokart racers recon that adding the pod make a big difference, especially downwind.
with the trials Ive done with my minis at 80-82kph the air starts to affect the underside, and you lose all traction. with the blowie, the shape of the pod kicks in and pushes you down.
so its not all just bling afterall
with my first promo there was a similar problem at 88kph, regardless of sailsize. with my new promo I cleaned up the airflow underneath, whilst raising the ground clearance, and the new configuration is good right up to 100kph.
that is the speed that the unbalanced wheels start to complain, so theres a next thing to start working on
The lake lefroy speed trials , last year were aimed at regular yacht types, to encourage people to get a cheap GPS and see what there regular yachts can do.
nobody brought a purpose built speed machine
most importantly we recorded the wind conditionsas well as peoples speeds , so we were able to get some great comparisons to NZ beaches

sn said...

veladaterra said...
the pilot dressed like a superhero?

Cheers - Enrico

where has that photo of landyacht in his lycra suit gone?

You mean this one

Thats being brave !

I agree - speed records for each class is a good idea 0 but lets not start an arms race, it is supposed to be fun !

IPKSA said...

Thats being brave !

I agree - speed records for each class is a good idea 0 but lets not start an arms race, it is supposed to be fun !

Thats the danger I think The Irish mini rules though should keep things reasonable
ie 5.6 M rope and wheelbarrow wheels for the minis

nebbian said...
I don't think that you need any lift on the leeward side -- that force is provided very efficiently by the wheel. A wing would just create drag.

On the windward side however, now that's a different kettle of fish

Right nebbian. I believe the leeward control surface should be neutral. But on high speed, a little lift on the leeward side will create a sliding wheel without any control or will reduce an excessive drag on it? Or maybe I'm still impressed by this It's real, preserved in Owls Head Transportation Museum, Maine. Built by Domenjoz, for sure a former Bleriot test pilot in 1930 and probably a merry prankster too... It deserved also a cover on Popular Mechanics.