How Does Hydrofoil Pumping Work?

Рет қаралды 6,160

Күн бұрын

Unlock or improve your ability to pump by gaining a through understanding of the mechanism involved.
Becoming a more efficient pumper will make every foiling discipline better: catch more waves surfing, stay up longer when wing or SUP downwinding, steal wakes from passing boats on the lake, or just have a fun afternoon with friends practicing off your local dock when betrayed by nature.
If you’re struggling with getting the timing right, a skateboard and pump track is a great way to figure it out, as well as hurt yourself in the process!
▬ Contents of this video ▬▬▬▬▬▬▬▬▬▬
0:00 - Introduction
1:03 - Pump Track Analogy
2:25 - Creating Your Own Virtual “Pump Track” For Your Foil Underwater
3:45 - Timing & Common Mistakes
5:30 - Keeping the board “Flat”
6:32 - Complicating Things
8:10 - How a Board Shim Can Make Low Speed Pumping Easier
9:29 - Conclusion
Check out our gear at www.omenfoils.com

Пікірлер: 26

@kirstanschmidt3351 Ай бұрын

Greg you make me want to be an engineer!! Thanks for your write up's on all the micro nuances - absolutely love it and will be using it on the water 🤓

@omenfoils Ай бұрын

haha, thanks Kirstan :) Please let us know if you notice improvements after playing with the technique - great to have the feedback!

@BigDawgzWingFoilReviews 4 ай бұрын

Great explanation! Lovin your Omen boards/foils. Some magic sauce in the content and gear Omen is providing.

@omenfoils 4 ай бұрын

thanks Chaz!

@dcmackintosh 7 ай бұрын

Nice video, but I think the most basic and important concept is missed. When the skateboard or foil is pointed down, and you press down to generate additional force by extending your legs, the reaction force (from the pavement, or foil's lift) has a forward component that accelerates the rider. When traveling back up, we retract our legs to reduce the load and rearward reaction force that would otherwise slow us.

@omenfoils 7 ай бұрын

Appreciate your comment @dcmackintosh, what you're saying depends on the frame of reference taken though. I’m describing pumping mechanics in terms of speed relative to the path traveled. In this case the normal force from the ground is perpendicular to velocity and the acceleration is due to the vector of the increased downward force which can be resolved in the direction of travel. Similarly, the decrease in rolling resistance/drag combined with reduction in downward force along the path traveled during the unweighting phase is valid and. In my opinion, these are more intuitive ways to look at the acceleration and climb phases. It’s just as accurate to think about it in terms of straight line velocity as you've descrived - in which case the normal force from the ground could be resolved along this straight line path and would affect velocity. Doing the math in either frame of reference would ultimately lead to the same result, but in my mind it is less intuitive to explain and think about a changing ground normal force rather than a changing downward force which is why I elected to use the latter. Perhaps I’m missing something though and interested to hear if you think I am making a mistake in logic here.

@dcmackintosh 7 ай бұрын

@@omenfoils Interesting discussion, thank you. Yes, any frame of reference could be used, including an observer on the sun, and calculations would work out the same. Most people should understand that when they point a skateboard downhill, they accelerate due to the pull of gravity, and people that have studied any physics know that it's the horizontal (perpendicular to gravity) component of the reaction force that is pushing them forward. If we push down against the slope with a force greater than our weight, by extending our legs, we can briefly increase the forward acceleration. I think using the board, or anything other than gravity, as the frame of reference is less intuitive and adds complication, but others may disagree. When foiling, I think a rider is also more interested in how fast their cg is moving forward across the water than the instantaneous velocity of the foil (following roughly a sine wave path) through the water. Because the instantaneous velocity and path of the foil when pumping is not the same as the more constant velocity and path of the rider, it does make sense to use the foil as the frame of reference if we want to actually calculate instantaneous lift and drag. (Of course, hydrodynamic lift and drag increase with the square of velocity, unlike what we experience with bearings and wheels on a hard surface.) I still think it will be helpful for most people if we use the gravitational reference when explaining how the varying lift and drag forces are helping propel us forward across the water, though.

@omenfoils 7 ай бұрын

Likewise@@dcmackintosh always informative to get into the details! The reason I was thinking about the foil speed as a point of reference is because it is ultimately what drives how long we continue to glide vs. stall. I agree most foilers would care more about their forward velocity or let's say VMG in general, however I do think pumping (at least when connecting waves in the surf or while downwinding) is a unique situation where the top priority is to stay on foil (avoid stall) more so than hit a max VMG.

@skobichevskii 7 ай бұрын

I was thinking the same thing. Something has to provide the overall horizontal thrust and its the increased horizontal (normal) reaction force on the downswing.

@FoilPatrol 7 ай бұрын

I like the visual simplicity of your videos. Makes it easier to concentrate on the technic.

@omenfoils 7 ай бұрын

thanks @FoilPatrol!

@skobichevskii 7 ай бұрын

I like your explanation better than others and looking forward to more videos.

@IRWE905 7 ай бұрын

Good explanation: One tip I give new Pumpers is to clap your hands over your head during the unweighting phase as this forces you to lift off the board and get the muscle memory. It's a weird feeling at first

@omenfoils 7 ай бұрын

That's super interesting! Never tried but will give it a shot. Have you ever watched a nordic skiier moving at maintenance/max efficiency speed? They have a really similar arm swinging technique to help the push and glide phases.

@nbaquizmasters1 7 ай бұрын

I love your Explanations! Waiting the next Video!

@omenfoils 7 ай бұрын

Thanks @jbcrespo6598! The video explanations are very new thing for me - feeling rather awkward in front of the camera so really appreciate the positive feedback. Will keep working on improving delivery and production value. Lots more content planned!

@gwendal5620 5 ай бұрын

Great video. I watched the video about the foil position on the rail, but it's still not clear to me where to place the foil. I would tend to say that centering the foil would be best to minimize the torque, as the torque depending on the center of gravity position of the board would penalize either the ascent or descent.

@JC.V 7 ай бұрын

Excellent !

@omenfoils 7 ай бұрын

thanks, glad you like it!

@sadorno 7 ай бұрын

Sweet.

@kountchev1 5 ай бұрын

excellent! "they" say HA foils are not to be really pumped as this disturbs the coming on the foil. so rather pushing the foil forwards while pumping rather than a up and down motion. thank you for sharing!!!!!!

@omenfoils 5 ай бұрын

When getting going on a wing with light wind it is very easy to stall a high aspect foil by pumping too hard like you say! What I like to focus on instead is to unweight the board while I am pulling in on the wing, this way when I get my maximum speed it is easiest for the foil and board to lift and when my weight comes back down on the board I am pushing forward to try and glide back down and gain more speed. Usually I skip off the surface a couple times, I can use this technique (along with the right equipment) to get up in super light wind with my 5m, 60L board, and 1050cm2 foil which ends up being way more fun to ride than big heavy gear!