Rotor Sail Boat?

[@Project-Air]

What do you want to see me build next? Comment suggestions below! 🚀💥✈️🛥️

[@donovanreid427]

build a modified ornithopter

[@donovanreid427]

or build a swashplate quadcopter

[@donovanreid427]

it would be better to use two sails with dimples

[@lwebius2111]

Make IT autonome

[@ypsaj]

I want you to build a V2 of this. I’m a former sailing instructor - look up the term ‘weather helm’. It will help steer you in the right direction (pun intended). Continue with the sailboat design - just model your boat after a known working setup (international A class catamaran could be a good starting point - note the location of the daggerboards). Good luck!

[@stonelaughter]

DIMPLES! You need dimples on the magnus surface to increase the effect. About the density of golf ball dimples.Also have it lower and more squat in shape to reduce toppling moments. It may also help matters when thrusting if you actually TILT the magnus rotor; not sure which direction but I believe it will definitely help with stability.

[@daveeckblad]

Dimples limit drag by creating boundary layer turbulence. Wouldn't you want more drag and thus thrust from this smooth cylinder? Seems to be what's used on large "Rotor Ships" if you look those up.

[@NicholasRehm]

@@daveeckblad Nope, dimples add energy to the flow allowing it to 'stick' to the surface better, so in theory a dimpled magnus rotor would be able to 'hold on' to the air longer, giving it more opportunity to divert the air for the perpendicular 'thrust' force

[@Mike_Rogge]

There is less wind near the surface of the water, a squatter rotor would be slower.

[@codetech5598]

If you add dimples, is it still the Magnus effect?

[@daveeckblad]

Show me an existing large scale rotor ship with a dimpled surface. Comaxel is a good example with lots of photos available. They're all smooth far as I can tell. From Sci America: "Dimples on a golf ball create a thin turbulent boundary layer of air that clings to the ball's surface. This allows the smoothly flowing air to follow the ball's surface a little farther around the back side of the ball, thereby decreasing the size of the wake." Obviously golfball spin stil imparts a magnus effect. I believe the effect is lessed by the dimples but obviously not cancelled out. The purpose of a golfball design is to move through the air with the least amount of friction wheras a rotor design relies on as much friction as possible to create the most thrust.

[@lorenzoporciani]

Real sailboats/catamarans have big centerboards, that are simply big ass vertical fins in the center of the hull, this helps to reduce the drift caused by the wind

[@flyingfamily1203]

As well they need to be centered under the center of pressure of the "sail".

[@MattBalder]

I think if you scale up your cat hulls x2, add centerboards and maybe try a slightly bigger diameter cylinder but possibly shorter you would have a great craft! It would be cool to have your centerboards attached to standardized holes as well so you can move them forward and aft along with your cylinder to get it all balanced and keep the hulls from digging into waves. Choosing a hull design like a Hobie 16 cat may be better suited to this experiment.

[@jobob2190]

as these big rudder act like a fin, i belive the centerboard can be also in front of the center, but as they are very back, the bow will always go down wind. also i would use long and thin hulls, lenght to beam ratio at least 10, as this is very effective, for ex. like all the military vessels. plus some dimples and maybe a wider and lower drum an it should go great. but anyway big effort and awesome speed, just nice!!!

[@dropjesijs]

@@flyingfamily1203 spot on. Also this will increase the distance between the rudder and the point the cat rotates around. Now the keels are fighting the rudder since they are both behind the center of pressure. So it would also increase maneuverability.

[@MrMarapro]

@@dropjesijs Came here to say precisely this.

[@olfatskootch]

A piece of string makes a wonderful recovery device, when you attach one end to the boat, and the other to the shoreline. This is best accomplished prior to sailing

[@robertweekley5926]

Or, a Fishing line, on a Fishing Rod & Reel! 🥴

[@kennethjanczak4900]

Unless u want to get wet

[@robt8593]

Being belt driven, options to add a double rotor in tandem or side-to-side. Might assist efficiency, balance and stability...or make it all worse :( Hope you have another go! Great channel!

[@weld4200]

Could use 2 motors tho to make it equal weight . belts tend to be kinda dense

[@brandonwood8971]

definitally needs a trimaran design to stop cap sizing especially if he does 2 Cylinders

[@mitchhifi9192]

Gyroscope time

[@alexyoung9710]

Yes was thinking the same thing, if you have them close together it may create a bit of Venturi effect making it even more efficient

[@susie3702]

If you do one with a double rotor try it with one clockwise and one anticlockwise to see if they help each other.

[@organic.seaman]

I loved your prototype. What drew me to this video is my passion for sailing boats and the idea of a rotor sail.. a few things I've learned about sailboats that could help improve its performance; in a traditional sailboat (mono or multihull), the boat moves forward using wings in the air and wings underwater acting in balance to generate a specific motion of the hull. The center of effort upon the wing in the air (sails) has to line up with the center of lateral resistance on the hull, the center of effort can be imagined as pushing a stick from its side across a table. Directly in the middle of the stick it will move straight forward, to either side it may spin on the center . For this reason , the two wings are aligned perfectly so that the boat doesn't "spin" upon those axis.or in seamans terms, go to weather or fall offwind.. sailboats are also ballasted with weight at the very bottom of the underwater wing , a keel. This is to keep them from becoming top-heavy and capsizing. On a catamaran there are two rudders that act in unison on each hull . Having only one can cause you to spin. There are also two keels on a cat. The keel and the rudder are always in line to ensure the boat sails straight (in most vessel designs). I loved this video and I hope you improve on the design and make a boat that actually sails very well with with the magnus effect!

[@lotuselanplus2s]

The bows of your catamaran should be like a normal boat hull and not have the bow sloping backward, thats whats helping to make it nose under when its underway, also move the motor etc back a bit further and maybe the carbon rods that join the hulls together should be maybe 3 inches wider so the hulls are further apart and make the catamaran less prone to capsizing .

[@Shreyam_io]

two parallel rotors(to vectorise the thrust/lift) or one flap (as in conventional wing) will be helping in further development if you are planning to approach Version 2.0 and the Sam guy is mandatory for your future project's susses

[@aurigo_tech]

Actually one rotor is enough, as the rotational speed of the rotor affects the amount of bending of the airstream. I am not sure it was considered here which might explain the control issues.

[@seanbrossard8178]

I thinking two rotors and counter rotation so lower center of gravity and no crabing

[@Shreyam_io]

@@aurigo_tech i will try to do some elemental analysis.. if I get some time after my college

[@aurigo_tech]

@@Shreyam_io Please share your results!

[@dr.johnh.watson2444]

the technical term for a such a sailing device is Flettner rotor invented by the German engineer Anton Flettner. and as mentioned a katamaran is not the optimal choice here. the boat can neglect internal volume for cargo or passengers a hull desing like the one used by J-class racing yacht would be the optimal. It features reduced drag compared to a ccargo ships hull and would have different to a katamaran self righting properties once the "sail" is "reefed".

[@tubegor]

The fact that I landed on this channel is not thanks to the KZbin algorithm, but rather the recommendation of DIY Perks. Very interesting channel with wise advice in the comment section according to the motto tinker and think along. Conclusion: subscribed immediately!

[@davidremer9468]

I think that part of your stability issues are from the rotor being placed behind the center of hydrodynamic pressure on the hull. Eg when the rotor produces a forward thrust, it is pushing behind the point at which the hull wants to naturally pivot in the water. It’s currently a positive feedback unstable system. It’s analogous to trying to drive with a trailer in reverse and keep it straight, rather than towing it, where the trailer naturally wants to stay aligned.

[@GiffysChannel]

Great video. I'm glad you're experimenting with the magnus effect. It's just one of those things that tugs at my imagination and wonders if there isn't more we can with it.

[@kshitijpatil639]

It says the comment was posted a day ago but the video was uploaded half an hour ago

[@Project-Air]

@@kshitijpatil639 Patreons get early access :)

[@dnomyarnostaw]

@Dave Doherty A cone halves the effectiveness ,for a problem that could be solved by leighter rig and better hull righting moment.

[@dnomyarnostaw]

@Dave Doherty Lower cg is good. His rotor was waaaay to heavy per scale. But whether you contra rotate in one mast or two, you STILL negate the lift from the other "spin" Its strictly one direction or the other with the spin orientation.

[@dnomyarnostaw]

@Dave Doherty Yes, the whole concept relates to the Bernoulli effect, but cone shapes are waaay less efficient than a cylinder, as the speed of the outside surface is higher at bigger diameters. Its height isnt as critical as its out of scale weight. he should be using thin mylar for the cylinder walls.

[@CooperZheng]

I think you need to move the Keel forward closer to where you want the Cp, that would prevent the boat vaning into current and keep it more on track.

[@willtaylor8904]

I see quite a few comments on putting the keel more central. They're all partially right. It's a question of center of effort and that's both with regards to effort generated by the rotor and the aforementioned keel. Clearly this can vary depending on the wind angle with respect to vessel heading etc... I hope that helps and I hope you go for MK2.. for what it's worth I think you should stick to the catamaran but with larger hulls for more buoyancy. You can maybe put them further apart for more stability...

[@UncleKennysPlace]

See the January 1984 issue of _Popular Science,_ I remember this from reading that issue, and looked it up. Extremely cool.

[@flyfishyfred8730]

Great video. It looks like there is some promise using the magnus effect in place of a sail. The hull design really should be a catamaran or trimaran. With the amount of surface area and the need for the rotor to stay near vertical, a cat or tri is your best option. You need to look at your center of effort for the rotor and try to balance the keels and rudders(make two) so that the underwater resistance matches(but a bit toward the back of the boat to ensure rudder authority) the rotor generated side forces.

[@vovanikotin]

Swath

[@gormauslander]

I don't particularly see how spending energy in rotation nets any gains over a traditional sail

[@ThereAreNoHandlesLeft]

I don't have anything to contribute, but I love to watch your creations. I'm loving wherever curiosity takes you.

[@benosborne7890]

Perhaps a vane to direct the airflow coming off the rotor could be used to enhance directional control

[@dnomyarnostaw]

That would work, but adds complexity and weight to the rig. Better hull direction, and slowing the rotors as the wind moves off the beam, would be the most efficient method.

[@benosborne7890]

@@dnomyarnostaw I would have thought a vane fixed at top and bottom and driven by a servo wouldn't be any more complex than a water rudder fixed at one end

[@dnomyarnostaw]

@@benosborne7890 It more complex because it would hsve to be adjusted for every little change in wind direction, snd boat course. It would potentially be and difficult to cope with ad a 360 degree boom on an ordinary yacht. A rotor alone handles wind change automatically because its is perfectly round. A shroud or vane may be useful when the wind is more in front or behind, but then you might as well make it a sail, as the windflow to the rotor would be all broken up and sliwed down.

[@the_shadow_11]

I’m so glad you’ve uploaded again- I’m really looking forward to the next super speed boat video too.

[@Project-Air]

Thanks! It's currently on my workbench and is being rebuilt for the winter months.

[@kenwebster5053]

What you call a keel is in a fin centre board and is like an under water (symetrical foil) wing. It is there to counter the leeway force vector generated by a sail or rotor in this case. The fins needs to be placed in a fore/aft position that lines up the foils centre of pressure with the rotors centre of pressure. So basically in a similar fore/aft aft position as the rotor. Where you have the fins, is just inhibiting the rudders from being effective. Sails are designed to reduce healing moment in strong winds but to use the wind gradient effect in lighter winds by exploit the faster wind aloft. Sailors make adjustments to sail shape, camber, twist and effective area to match the conditions. It's complicated, Your rotor, can't do that but you could make it conical so that you have more area down low than aloft. This would lower the magnus reaction force reducing the heeling moment (reduce risk of capsize). Also make the top of the rotor very light weight so that it doesn't overbalance the boat like it is doing when it heels. Also, your fore/aft weight distribution needs to be on the centre of buoyancy. Even with moving the rotor aft, it isn't aft enough this is causing the boat to capsize by tripping over the lee bow. Better success next time.

[@NH-vf4se]

Nice prototype, the simplest way to gain stability would be to use a truncated cone instead of your cylinder. Using a small slope, the bigger base downward will produce a differential in the thrust pushing the down side (bigger base) stronger than the top both against the wind and using the magnus effect.

[@keithbrown2458]

Absolutely one thing you proved to me, that you have a good friend any friend that would jump in a lake with nothing but a nickers (I think it’s you call them) is a friend indeed

[@csf6614]

Really enjoy your films man... just remember it's not failing its learning and funny ....

[@thysl]

Put the keel further forward, the water pushes the nose in the wind atm. I sail myself, and i think that might fix your problem. Keep going! 👍

[@dnomyarnostaw]

Also, the lift on the Rotor tend to pull the short hulls towards the wind.

[@emily36130]

This little rotor produced way more thrust than I expected

[@msbealo]

You need; two rudders, two centre boards or keels, further aft placement of cylinder to reduce pitching moment and enough righting moment to counter-act the roll moment of the "sail". The cat is a perfect platform but the height and width are issues. Less height to reduce roll and pitch moment, more width to increase righting moment (stop it getting blown over) and more length to increase pitching stability (stop it nose diving) - or a smaller cylinder. Centreboards (well placed) are essential otherwise you'll mostly be blown downwind. Happy to talk.

[@nikonaumann3457]

add another rudder on the other hull if you go with the catamaran design again

[@Taverius]

I wonder if you can gain efficiency by also having a bearing up at the top of the rotor and holding it in place with some carbon fibre rods. Certainly if you decide to ever scale this up I'd recommend it, those bearings are probably losing a lot of efficiency dealing with torsion.

[@stanleydenning]

I wonder is a dimpled surface along the tube, like a golf ball, would improve its efficiency.

[@mdramirez0001]

The hydrodynamic forces under a sailboat should match the aerodynamic forces above to be stable and controlled. Right ?

[@dnomyarnostaw]

Right. But they change as speed changes. just needs longer hulls and two rudders like every other catamaran in the world.

[@piersbowlan]

Full sized catamarans have a rudder on each hull working in tandem. A keel on each hull will also help with directional authority. More hull volume forward will also be of benefit (as someone else suggested). Nice project. 👍

[@bradleydenhollander4401]

A few notes about the lack of direction control. I am a young man in Canada that does a fair amount of sailing, on primarily a prindle 18. The hull designs firstly are a-symetrical, therefore meaning that in theory that would eliminate your need for daggar boards. The real issue I see here is that you dont have your center of pressure in the right spot. from the looks of it the boat keeps moving straight into the wind, therefore meaning that your center of pressure is too far back. Also It seems that the issue was worse the second time after you had moved the rotor back, supporting this theory. Theres a lot of science behind this, but looking into exactly where the center of pressure is might be a helpful idea. I have a feeling that making the boat longer to counteract the torque applied by the forward force at the top of the rotor while simultaneously getting the rotor in the right spot might help. On a side note adding another smaller rotor toward the front might do the trick similar to the way a jib or the front sail on a boat generally works. Just my thoughts. Anyways, great video, keep it up!

[@newmonengineering]

How does the diameter effect performance? Would a larger diameter cylinder create a larger effect?

[@dnomyarnostaw]

Yes, it makes a huge difference. i will put a link in my next comment to the XL spreadsheet formulae for Rotor lift.

[@5alm0n]

Awesome work. Go for a bigger boat 🦈

[@ThorLarsen]

Was there some reason why you didn't do a direct drive? Otherwise, it seemed (despite a few small difficulties) a fantastic project.

[@dnomyarnostaw]

You get more performance of the wind in the rotors than trying to drive a propeller by the wind, in the water.

[@ThorLarsen]

@@dnomyarnostaw I meant, drive the cylinder directly, rather than a belt drive. There would be fewer moving part, less parasitic drag, and probably longer run time, too. Obviously, if a propeller were used it would just be an odd looking traditional boat.

[@dnomyarnostaw]

@@ThorLarsen Oh, I see. Yes, true, lack of gearing makes for efficiency. In this model, the economy of operation is hardly critical, but on large ships it is a big consideration. The MV Estrada Rotor Ship used heat from her Diesel exhausts to run the four Rotors, that's how little actual energy is required.

[@GeographyStuff420]

Yes make a version 2!

[@rjung_ch]

Sam's the man, well done you guys, bet a sequence will follow in the near future.

[@danielfreytes8297]

The boat was fine. It just needed to be wider, so the boat won't topple over. Maybe add a flywheel spinning opposite the rotor to oppose the spinning force.

[@Andre_Thomasson]

or add a second rotor

[@keyper555]

I have been into RC's all my life, grew up on the water and had many rc boats, the one thing most important if your going to be on the water is this, have a chase boat, like a blowup boat or rowboat, very important, especially if the water is to cold to swim in, or a chase rc boat with grapple hook on a fishing line and float, therby eliminating having to watch your boat float away and not being able to retrive it. have fun and good luck on your project, very interesting, I once had a cat sailboat, was very fast and fun, went like a bat outta hell lol

[@CalToxReaper]

For V2 Add a second rotor, rotating in the opposite direction it should help stablilty and direction catrol, a lot of the ships disingles i seen this on always had two.

[@Superwoodputtie]

"I've see other people struggle a bit with their 3D printed hulls." Haha, a cool shout out to RC testflight.

[@Robot_Child_Productions]

Haha, yeah he has some pretty cool stuff. Especially the autonomous aircraft

[@dogefort8410]

@@Robot_Child_Productions solar catamaran tugbot isnt all bad either.

[@Robot_Child_Productions]

Fair

[@jamesbrett9537]

As a sailor, I think what you need is to move the keels forward so they are directly in line with the rotor when looking from the side of the boat. The purpose of them is to counteract the lateral forces produced by the rotor which try to drive the boat sideways. Also if the boat ever points directly into or away from the wind, stop the rotor as it's force will be directly sideways causing the boat to capsize.

[@jamesbrett9537]

Also, the keels and rudder on a sailing catamaran would normally be significantly larger than what you are currently using.

[@teamseacts]

the center of lift of the rotor and the center of lift (resistance) from the combination of keel and rudder need to be in roughly the same lateral position on the boat in the direction of travel. With the keels so close to the rudders, the force of the rotor easily overpower it. The keels should be in front of the rotor. while the flat plane of the keel and rudder will work, you would really benefit from a true foil shape as they will generate relatively free lift to overcome the side force from the rotor. Last point....the further you place the combined center of underwater lift (resistance) behind the rotor, the better the boat will tack into the wind but at the expense of controllability at slow speed until the underwater lifting surfaces get enough speed to overcome the offset forces.

[@bob2161]

When you undertake experiments on the water, a bit of pre-planning is in order. Namely, a recovery device for the experimental craft. Here in the states, what I have used in a very similar situation, is a children's fishing pole. It is only about 1 meter long, and it comes complete with a preloaded reel and a casting weight. IIRC, it was only about $10 at Walmart. On it's first outing, I used it 4 times, big success. Truthfully, it was the only success on that first outing. On the second outing, I simply attached the fishing line to the boat and set the casting release. The line just spooled off the reel as the boat made headway. When it needed to be recovered, it was a simple matter of picking up the fish rod and working the reel. I do not know if fishing is as popular there in the UK as it is here in the US, so I don't know if a child's fishing rig is easily obtainable over there. However, I'm sure you could print up a simple reel on your magic 3D printer. Just make sure it has a provision for holding enough mass (perhaps a stone) to keep it on the shore as the line pays out. About the magnus rotor, I would like to offer some suggestions. How about a dimpled surface, like that of a golf ball. I seem to remember reading somewhere about that improving the performance of the rotor. Also, you might like to experiment with rotors of different diameters. I believe there may a correlation between diameter and efficiency at different airspeeds. Think larger diameter for lower speeds, thinner for faster speeds. I've also seen a drawing in which the wind was also the driving force that spun the rotor. There was a vertical windmill arrangement deployed around the center of the rotor, at a considerably larger diameter. There was a means of reversing the pitch of the paddles in order to reverse the rotation of the rotor. I only saw the drawing, I do not know if such a thing ever came to be tested. I'm just offering up some ideas here. I really enjoy watching you tackle the different designs that you do. Oh, and don't forget your Wellies next time! 😀

[@Sembazuru]

How are you countering the torque of the spinning rotor? I didn't watch that carefully to all the tests, but the couple that I watched the direction the boat was trying to turn in relation to the spinning of the rotor it seemed to me that the boat heading change was counter to the rotor spinn direction. Or is that what you were hoping the rudder and the vertical fins that you glued on would do? At a risk of adding too many more moving parts, maybe a driven flywheel mounted to the underside of the deck spinning counter to the rotor, along the same rotational direction would help act as a reaction wheel.

[@macrumpton]

Having a quick swappable module with a regular sail and another with the rotor would allow an interesting comparison.

[@roydengillies]

If you build another catamaran hull, you should consider making the hull much wider to give more stability. Remember, when you have that large cylinder spinning, you have to consider gyroscopic precession. When you have the wind coming in from the side and your cylinder generates its forward pulling force, gyroscopic precession will occur and your boat will try tip over into the wind.

[@Zilahi-Branyi_Laszlo]

Boats are intended to rotate around their keel, as that part resist the hardest to sideway movements. You put the keel at the back of the boat that cause its rudder is barely effektive due to the very small leverage, however it give very high leverage to the wind to turn it away. If you want good control and stability, move the keel about to the center of gravity, or a littlebit even further to the front!

[@Robot_Child_Productions]

That's so cool! It's similar to the ones being tested for full scale ships

[@MCsCreations]

Awesome work, James! 😃 Looking forward to see the improvements you come up with! Stay safe there with your family! 🖖😊

[@markbrake7337]

A wider beam would help counter the toppling effect of the rotor. The rotor is basically too big for the beam and has made the boat "tender". Larger fin keels more centrally positioned along the lengths of the hulls would also help with directional stability. The rudder will work fine if you have more speed. It would help being centrally positioned between the hulls, but its efficiency directly correlates to the amount of water flowing past it. A tiny rudder would work just fine if the boat went fast enough, and a huge rudder would be fairly ineffective with very little forward motion. Hope this helps. Good luck.

[@MichaelMcFearin]

Version 2 please, I have always been interested by the magnus effect.

[@colleenforrest7936]

Looking really cool! Definitely need a bigger boat though. It's top heavy. Your boat has to have the right dynamics to countermand the effect of the mast leaning so it rights itself. Lots of ways to do that. Maybe put the outriggers out farther on each side than the mast is tall and give them a little ballast... and a bit bigger. The idea is that when the boat tilts, you want the downward force on the outrigger out of the water plus the upward force on the outrigger in the water to be greater than the downward force on the mast.

[@fuba44]

Skip version 2, go for version 3. Loved it.

[@guytrout7101]

Well done. The boat swamped over because the catamaran hull was not large enough to handle the effect of the wind on the vertical cylinder. Maybe weighted keel fins would also help keeping it upright.

[@bry29bry]

This is pretty cool! The real world applications are already happening! Large bulk carriers and cargo ships are starting to be outfitted with the Magnus effect masts to make the vessels more fuel efficient. Great video as usual!

[@LemmingGoBoom]

They're called "Flettner rotors" en.wikipedia.org/wiki/Flettner_rotor

[@SawDustMakerRJM]

Version 2. Yessssssss!

[@kevinlind4640]

"Ohh, no, my rudder's just fallen of"... Best summary of this channel that I've ever heard!

[@Barillaa]

Sam is the real hero of this video! That look very cold!

[@jommeissner]

With two separate Rotors not only the drag would be more directed, but you could also provide steering by different rotation velocities or directions.

[@Fistrike]

Is there a reason to not try 2 parallel rotors with opposite spins one in each side of the boat, to avoid the spinning momentum from tipping the boat and possibly even use different speeds in each rotor to steer?

[@austinsatoskar8151]

Your channel just showed out of nowhere kind of like stuffmadeheres did and I see huge potential. Your explanations and overall ability to keep the video entertaining is extremely professional. Love the stuff you're doing. I will be once work dies down starting a channel on lasers much like the legendary StyroPyro

[@alanicus6969]

I might be missing something here, but is there no defined 'direction of thrust'? Maybe use the tube for the effect in conjuction with a sail or two, rather than exclusively?

[@MichaelTeeuw]

ProjectAir seems to become the channel of failed experiments. “Oh no! The rudder fell off!”. But somehow it makes this channel stand out. I love it. Keep up the fun stuff. 👍🏻😬

[@angrymario8259]

I really like the channel because it doesn't just shows the finished and functioning project but also the fails

[@PortCharmers]

From a pure scientific point of view an experiment is not failed if it produces a clear outcome and the procedure is sound and not compromised by outside circumstances. The success of an experiment is not dependent on whether the outcome is expected or favourable. Hypothesis: clamping the rudder on with a maggot screw without filing a flat surface into the rudder shaft will do. Results: rudder falls off Conclusion: Nope! Not failed at all.

[@f.n.schlub]

Decades ago during a global energy crisis some ocean freight companies mounted something similar on huge cargo vessels. These were unpowered. The wind caused the cylinders (with variable vertical blades) to add as much as 25kts to the ships' forward velocity. A huge financial savings. I don't know why they fell out of fashion.

[@StainlessMessenger]

I did not know that anyone was clever enough to add vertical blades to make the rotors self spinning. Neato.

[@fredrickdakine]

Very cool! I'd love to see a profile for a kite driven "sail boat".. If you have a with spreaders at the top of a mast (so that the lines are spaced apart appropriately and don't tangle), you could run the kite on a very short retractable tether, so have good control over it.. Then all of your "sail" is in the higher loftier winds.. Should be much more efficient. It would be interesting to attach the mast to a slide circling the boat so that it's always pulling from the leeward side of the boat, instead of the centered, which should decrease heeling, though that would effect any plans for routing the lines.

[@AdventuresofGraywolf]

The magnus effect is going to be strongest at 90 degrees from the wind. If you could direct the wind into the cylinder so it's hitting at 90 degrees from your desired heading, it should be much more efficient. This would theoretically allow you to travel in any direction, regardless of wind direction

[@bobododoo3925]

Hi. I'm looking for an answer. the force arising from rotation tends to overturn the sail, just as it happens with a conventional sail, or is it directed strictly horizontally?

[@aurigo_tech]

Always great to see Flettner-Rotos popping up again. Anton Flettner would be proud! Also good to see more and more commercial applications for them. You didn't mention it so I don't know if you did consider this: the optimal speed of rotation depends on the direction of the wind (and perhaps windspeed as well?). As it essentially bends the stream of air more or less. So considering this could solve the control issues and provide more thrust. I don't know about the math behind the optimum rotational speed, but a series of tests for different angles of attack against the wind could give insight.

[@CraigLandsberg-lk1ep]

Would you not need two counterrotating drums to make symmetrical thrust?

[@onbedoeldekut1515]

Could you give it one extra outrigger, which moves like a sail boom around the spool mast to whichever degree wants to sink itself? Being 3D printed, you could even print-in-place an axle of sorts that turns the outrigger pontoon to always be pointing in the direction of travel as it rotates around the central spool.

[@MissionaryInMexico]

Years ago I used to have an "RC Aircraft" group in an international website, before I handed it off to another member. Being the son of a scientist, this channel is extremely interesting to me.

[@alisioardiona727]

You should widen the gap between the hulls and put long heavy keels at the longitudinal CG of both hulls.

[@ftsang2776]

good job man! and some suggestion, 1. shift the centerboard close to the c.g. of the boat. 2. possible to have some sort of flap/rudder down stream the sail to have some wind steering? (the reason need centerboard to balance lateral force). 3. how about a conical sail to improve stability?

[@Kepe]

A Finnish cruise ship was the first passenger ship that had a Magnus effect sail installed. It had it on for a few years as a test to see if it improved fuel efficiency. Apparently it does improve fuel efficiency "up to 20%". You can google "Viking Line Grace Magnus" to find some info on it.

[@frederickdvorak6502]

Possible improvements: a) 2 rotors on either side of the mid-ship position? b) Shorter rotors to drop the centre of gravity, and reduce the risk of capsizing? c) 2 dagger boards, mid-ship, to help with pointing and going upwind, and with reducing risk of capsizing? d) 2 dagger boards with foils might give the hulls more lift, thus reducing friction and increasing speed? e) 2 rudder, as in real-size catamarans, to reduce drifting and going in circles? 2 rudders are also more efficient.

[@themadscientest]

Please stop using WD-40 in bearings, use grease or oil.

[@aiki6378]

Why?

[@baraki808]

​@@aiki6378because WD-40 is a degreaser. You need grease in the bearings to increase it's lifespan. By applying WD-40 you remove that grease.

[@aiki6378]

@@baraki808 ah, much thanks

[@boxlessthinker1973]

It is? I’ve been doing that wrong for decades it seems…

[@williamrobinson7460]

​@@aiki6378I heard wd stands for water displacer. WD 40 is excellent at getting in every nook and crany and drive out moisture. WD 40 is bad at hanging around, has no long lasting protection against exposure and poor physical protection.

[@ro-ce8vg]

did you put wd 40 in skate bearings? wouldn’t that wash away the lubricant already in them?

[@CAMacKenzie]

My wife and I were talking about your video and she asked about a collapsible rotor. The thought occurred to me that it could be built sort of like the old Tunnel Fun toy, a coil of springy material (maybe fiberglass) covered with fabric, set on end, with a rotating mast inside to drive it.

[@CAMacKenzie]

Another thought I just had is that if the rotor were tapered, there would be less lateral force aloft, where the moment arm is greatest, and the boat would be stabler. Also, slightly less weight aloft. Somebody must have thought of this, as it seems so obvious. Regular sailing vessels have sails that taper upward, either approximately triangular sails or, on square riggers, smaller sails aloft.

[@1337fraggzb00N]

A wind-powered boat. What a splendid time to enjoy modern technology.

[@PeterKNoone]

Bigger catamaran hulls for more floatiness?

[@rendrakw7103]

What is used to rotate the rotor? If still engine/baterai, isnt it still cost fuel?

[@AxeMurderer2222]

Need to be able to tilt the mast a few degrees remotely. If you want it to behave like a sail you need the ability to vary the relationship between the thrust vector from the cylinder/sail and the hull axis. Or maybe just slide the whole thing side to side outboard might work. Or add another mast/sail and offset both of them. Then you can run them at different speeds or directions or put them on a rotating platform to achieve some control over it. The way you have it designed where the angle is always fixed & centered & aligned with the hull axis, as soon as the hull turns away from the wind, so does the sail and it goes limp. You will never get that thing to turn around. Also add a deep keel onto your hull so it isn't so top heavy. I think choosing a dual hull design is good. Single hull tends to run with more of a list which might overcomplicate things having the cylinder tilting a lot in stronger winds. The catamaran stays more flat so I think that makes it easier. It just needs more bulk under the water line. Maybe make it a bit wider & longer too for better. stability. You could even add outriggers. I think one of the problems you have is the hulls are just a little bit too small to support the contraptions you're putting on top. The hulls ought to be longer than the mast is tall. Instead of using straight cylinders, have you done any experimentation with other shapes like tapered more cone-like sails? With traditional sails the weight is not evenly distributed. Sails are very light at the top and very heavy at the bottom where the bulk of the material is. The material captures the air, more material at the bottom = more air at the bottom too. Seems like a conical cylinder would be a better choice to replicate that weight distribution...if it works. Likewise with the thrust. Using a cylindrical shape the effective thrust will be halfway up the mast. With a cone shape this gets lowered closer to the hull. When the thrust is higher, there is a greater force driving the bow underwater and the stern out of the water. Lowering the thrust vector helps to reduce that force and redirect it into pushing the hull forward more. Moving it more towards the stern does the same thing. The position of your mast should favor the stern of the ship. If you could make the profile of your cylinder look like the profile of a sail...

[@btdarterschannel112]

What about associating a vertical "wing" with the rotor? When the effect is used to create lift, I've always seen it in association with a wing. 🤔⛵📹❓

[@SterremanWillie]

You also need a keel/centre-board to stop of from going sideways.

[@williamestep5473]

Perhaps use a small tube on the front instead of vertical. Possible to use magnus effect to give lift to boat enough to just skim water without foils?

[@taattataattataattata]

Keel needs to be at center of pull from the sails to increase sterling. Move keel forward to turn easier. Great video. thanks mate

[@boomfiziks]

I sail a wind rider sailboat, which is a trimaran. It’s highly stable (nearly untipable. You may want to consider a trimaran design. Thank you for the content! I’m going to show this to my science students. Thank you.

[@Project-Air]

Thanks for watching!

[@TrCic]

May i suggest you look into set screws? I'm sure it's not much but having screw heads sticking outside spinning parts is sure to be throwing the balance of the spinning parts off some what? Also makes builds looks cleaner, imho.

[@Bill-lt5qf]

I wonder if the Magnus effect works with water, i mean, it's just another fluid. Maybe a machine that uses the flow of a river to travel up the river?

[@egeoeris]

I'm worried if water's viscosity would act as a surface anchor, perhaps rotating the boat by accident. Perhaps a higher rpm thinner rod would be sufficient...

[@Bill-lt5qf]

@@egeoeris I wish i knew the answer. But the Magnus effect is so counterintuitive that my uneducated brain can't even theorise on an outcome.

[@whiss42]

Magnus effect does work in water the same way as in any fluid, there was this company active some years ago who was using it to stabilize boats : kzbin.info/door/MZ-fm15L52HwAZjNuukxKQ However I'm not sure I understand how you could get a shape & orientation to counter the drag of a hull and its own and use the lift to travel up the river ?

[@Bill-lt5qf]

@@whiss42 Thanks for the link, looks like a stabilizer is a more logical use of the effect underwater. Still got the feeling that a propulsion device should be possible though. Maybe two cylinders, rotating counter to each other (avoiding yaw twist issues), creating a high pressure zone between the two, with some sort of fin/fins to redirect the high pressure zone backwards. Just wish i was smart enough to know if that would work... would that work in air?

[@whiss42]

@@Bill-lt5qf Yeah I think I'll look into it further tonight, but so far I couldn't find a way... It would be amazing, maybe with multiple cylinders or coupling a cylinder & a foil something is doable... Usually what works in water can work in air at "not crazy" Reynolds numbers, not necessarily with the same efficiencies tho (Magnus effect is somewhat proportional to the density of the fluid it happens in)

[@Wolfgang-the-Gray]

So how fast would it go if the motor spun a prop in the water instead of the rotor drum?

[@ZzHasbrozZ]

How would two tubes improve it? Spinning same or opposite directions?

[@Lecandotnet]

Can you attach a nylon string ( fishing line) for easy pull it back?

[@alwiesbauer3117]

what would happen if you used a Paint Brush Roller for the wind device, would the fuzzy's help, maybe used a scuptured one or with hairs on it???

[@ajpbknex4117]

Look promising. Thanks for sharing what you use to seal you boats.

[@mybackhurts7020]

You have to use to like they do on the big ships

[@jannepoikonen9388]

Could magnus effect work with low flying boat? Ekranoplan? Ground effect-magnus effect combined?

[@honewaatamokepumipi8135]

Really impressed. Definitely outside the square innovation. Well done sir

[@scottsample9681]

Would the spinning rotor work better if there were several smaller ones rather than one big one? That would resolve center of gravity issues. Also by having several of them, you can have more surface area than 1 large one would have, which I would assume more surface area, better effect.

[@maskpsychoses4761]

What would happen if you put some texture or small blades on your cylinder ?