Hydrofoils-quadrofoils and retractable or foldable foils

[maj.klancnik]

Hello. I'm trying to make a hydrofoil with retractable foils (using hydraulics). Can anyone confirm that the slovene quadrofoil has in fact retractable foils? Why hasn't anyone used this idea?/And if the idea simply wouldn't work, can anyone tell why?

Thanks for your advice

 

[kerosene]

for something like the quadrofoil (http://www.dailymail.co.uk/sciencet...n-flies-water-25mph-without-making-noise.html)
to be possible it has to be extremely light. It can really do one thing and that is impressive enough if claims are true. You add hydraulics and power needed for those etc. and you lose the primary feature.

 

[rwatson]

Foiling is just a function of power. This 'thing' is under 10 hp.

For hydraulics and foils, you don't have to have an amazingly big engine. It would not be a huge ask.There are plenty of smaller retractable 'foil craft.

eg
http://www.diseno-art.com/news_content/2014/10/hydros-hy-x-retractable-hydrofoil-boat-prototype/


You would definitely need a bit of engineering advice for hull design. foil design and weight allocation.

 

[Skyak]

Hello. I'm trying to make a hydrofoil with retractable foils (using hydraulics). Can anyone confirm that the slovene quadrofoil has in fact retractable foils? Why hasn't anyone used this idea?/And if the idea simply wouldn't work, can anyone tell why?

Thanks for your advice

I only watched a few videos but it does not appear possible that the quadrafoil could possibly have 'retractable' foils -they appear detachable.

Regarding why nobody makes a hydrafoil with hydraulically retractable foils, I would say it is difficult to justify the complexity of the gear. The hydraulics are a fix for a problem that manufacturers (or their salesmen) would prefer to simply overlook or downplay. I don't see any reason it can't be done, I see a mountain of reasons it might not be a commercial success. Hydrofoils have a limited performance advantage and adding the weight and complexity of the deployment just brings them to an apples to apples comparison that is not favorable. It is easier to sell a shiny sweet blabla fruit (attractive unknown) than it is to sell an overpriced ugly apple.

One other note -the quadrafoil uses the efficiency advantage of foiling to overcome the cost disadvantage of battery energy storage. An electric boat with a conventional hull and the same speed and range would cost the same or more.