Also knife edge the front of the propeller blades and smooth the front and rear almost to a polished finish….. Then you can graduate to removing material of the blade to create a mild cup to further tune the prop.
That makes sense! I bet the variables determining the proper size and pitch ratio are the weight and drag of the boat or sub, and the type of motor (higher HP vs higher torque)
Make the front of the boat narrower and sharper. It will reduce the resistance given by the water and will provide more speed. Don't forget to add little weight to the bottom of the boat to balance it or else it will flip
Yeah, nah. I'm guessing it is an issue with motor torque vs efficiency. Bigger prop needs more torque from the motor to drive, which I'm guessing is over the hump.
It's as that turque guy said. Bigger = more torque on motor = less rotational speed. He need to map out that time on a graph to get the best propeller size for that specific motor and boat.
@@paulh2981 because its not feasibly possible to have missions of propellers on the back of a ship in both resource costs and weird hydrodynamic things that make it worse than those big propellers. Its the same reason we dont have a hotel thats 20 miles long and 20 miles wide, it may be more effecient housing in terms of people per square foot but it runs into alot of other issues from resource cost, to terrain, to building stability, and much more.
Naval architecture and marine engineer here. For that scale of propeller and power on it I strongly advise to reshape the hull if possible. If not at least make it longer or thinner.
maybe use 2 contra rotating props to increase stability as it looks like the torque is twisting the hull of your boat. Its a similar fix they used in ww2 on planes. even 2 side by side props would probably mitigate it if they spin opposite directions. See the p38 lightning for that configuration
Btw the size isn’t the only thing you should change you should also see what tilt/pitch of the blades on the propeller becuase that will give more power or more speed
When optimizing pitch this thrust at speed zero experiment might not be the best idea. Propellers with a high pitch should reach their max thrust at high boat speeds. Essentially increasing the boats top speed whilst making it harder/slower to accelerate from zero. Also consider, that your propeller might actually spin to fast. You might want to consider a larger propeller driven at a slower speed by adding some form of gear box/transmission.
Toroidal propeller! That's your next upgrade. Also, I need to see these tests again with similar sizes of toroidal props. I predict the same size optimization, but significantly more thrust
You should make a graph using excel and plot the propeller diameter on the x axis and the thrust on the y axis. If you extrapolate the curve, you can see exactly what radius of propeller will give you the most force before it starts to lose power
That boat needs bilge keels and a slimmer stem for increased stability and decreased wave resistance, which ultimately makes a more stable and faster vessel
If you make the Hull sit deeper in the water, you'll get more stability. kind of like a fishing kayak compared to a river kayak. You can do this by adding some weights to the bottom to make the boat a little heavier. Another thing you can do is make some little outriggers so it can't flip
Your boat would improve by having a "underwater nose" and body it will stabilize the fourth propeler and might also help if you use two propelers instead. Which should be spinning oposite of each other. Also dont forget to put some weight underwater which should not change with the movement! Soo no water or sand or grains you need actually ballast there.
Add some small fin at the bottom to redirect the flow of water making the boat go straighter as well as a small fin to make your boat turn when you wanted to
You should add-on floats on both sides to make it float better and increase stability And on those floats on the side you could move your propellers there for better turning
Here’s what I would recommend: use a higher Kv motor, that one is wayyy too low to efficiently use one of those props. If you use a higher Kv motor, you will have less torque (you’re not even barely using the torque this motor has) but a higher top end RPM.
You should make propellers slightly smaller and larger than 3 and see which one works better. Then keep doing that until you find the most efficient propeller size. Then do it with different sized/weighted vessels. Do it all the way up to an oil tanker and revolutionize the marine industry. Good luck!
You should really print some higher quality ones for boat propellers to be efficient. It is really really important for them to be a smooth as possible and as balanced as possible for the best hydrodynamics and probably use some sandpaper
Put a tube under the center of the boat with two angled cuts on either side to let side water rush through as well. Put this in line with the front of the propeller, and it should (i think) create more of a jet like effect.
Have 2 propellers instead of one. - If you have them at the front and positioned off either side, you would have better and tighter control during movement and more stability when accelerating.
I have an idea that came from military helicopter engineering that could make the stronger rotors more stable. Twin rotors. Take a rotor place it put another behind it, flip it and make it turn in the opposite direction with the same ammount of power to make the inertial forces balance out and the thrust reach twice the normal level.
Smooth the propeller, Add some sand for weight, ajust the pitch of the motor up a tad. If your eager enough, Make the frount of the boat more if a tringale shape
That’s not the only problem. The thrust-measuring rig doesn’t give the thrust at the prop, it reads approx 3x the actual thrust. Principle of Moments and all that.
There is a motor power to prop size ratio. P4 was bigger but the motor didn't have the power to turn P4 at the same RRM as R3 to push the water. NOW THEN... P4 MIGHT go faster as momentum is generated. This is not examined in your test.
the biggest Improvement you can make to those impellers is improving the geometry and the print quality cuz currently those things are going to have more drag than a gay bar in Vegas so either send them down and put a filler primer on it and do all that stuff or buy a resin 3D printer or use a service to have them printed in resin
give it a piston engine, using hydrazine as fuel, and an even bigger propeller and increase the hull size to support the added weight, also more length to make it more stabile. trust me, its going to go like a rocket on water :)
You should put some small weights not to many though just to balance it.
or make a keel
basically ballast
@@panzer.kampfwagenyeah
@@panzer.kampfwagenlike the cargo ships with "indoor pools" to simulate ocean behavior?
@@gameseeker6307 that but much much smaller
It’s not just propeller size. It’s also propeller pitch. Depending on the pitch, it’ll have more acceleration/torque or more top speed.
Also knife edge the front of the propeller blades and smooth the front and rear almost to a polished finish….. Then you can graduate to removing material of the blade to create a mild cup to further tune the prop.
I wanted to post this to you so maybe you can further this info with your comment
Will do 👍😁
Make propeller smooth
That makes sense! I bet the variables determining the proper size and pitch ratio are the weight and drag of the boat or sub, and the type of motor (higher HP vs higher torque)
Make the front of the boat narrower and sharper. It will reduce the resistance given by the water and will provide more speed. Don't forget to add little weight to the bottom of the boat to balance it or else it will flip
Doesn't have to be sharper
@@yuanfurbaxyes it does due to the high resistance and pressure of the water compared to air with low resistance and very low pressure.
Longer hull will also give stability. But I agree, too long and it'll capsize easily.
Bigger boat + more smooth design and more ballasts for better stability
@@skyfallback but why sharper? Why isn't narrower enough?
For those wondering why 4 wasn’t the fastest, it is pretty big so it creates drag
Yeah, and the boat is too light so the control would be wild
aren’t cavitations also an issue with 4?
Yeah, nah. I'm guessing it is an issue with motor torque vs efficiency. Bigger prop needs more torque from the motor to drive, which I'm guessing is over the hump.
Maybe it conpromises volume moved with weight?
It's as that turque guy said. Bigger = more torque on motor = less rotational speed.
He need to map out that time on a graph to get the best propeller size for that specific motor and boat.
Welcome to the world of Fluid dynamics.
Bigger is not always better.
Then why do big ships have enormous propellers instead of millions of #3 here
@@paulh2981 because its not feasibly possible to have missions of propellers on the back of a ship in both resource costs and weird hydrodynamic things that make it worse than those big propellers. Its the same reason we dont have a hotel thats 20 miles long and 20 miles wide, it may be more effecient housing in terms of people per square foot but it runs into alot of other issues from resource cost, to terrain, to building stability, and much more.
Naval architecture and marine engineer here. For that scale of propeller and power on it I strongly advise to reshape the hull if possible. If not at least make it longer or thinner.
gotta fill and sand that propeller, the smoother the surface the better it will work
Yes!
Yep
You got shouted out so congratulations!
“1 is the smallest and 4 is the biggest. Lets do a thrust test”
You need to design a hull that allows the boat to glide and exceed its hullspeed.
A lead keel would be very helpful for stability although you will slow down a bit
Interesting, I've never heard of that!
You could add a small gyroscope btw
@@makermandan lead as in the metal not as in the adjective
You could try making it a hydrofoil boat...
Real life boats use lead in their keels
Next upgrade: "Add a fin on the back so it's more aerodynamic."
Get a mini version of yourself either doing titanic or paragliding ☺️
maybe use 2 contra rotating props to increase stability as it looks like the torque is twisting the hull of your boat. Its a similar fix they used in ww2 on planes. even 2 side by side props would probably mitigate it if they spin opposite directions. See the p38 lightning for that configuration
Btw the size isn’t the only thing you should change you should also see what tilt/pitch of the blades on the propeller becuase that will give more power or more speed
That's true, but I wanted to control for pitch in this experiment.
@@makermandanI don’t understand what your saying?
@@makermandanalso a extra wide catamaran style hull could help with stability
When optimizing pitch this thrust at speed zero experiment might not be the best idea. Propellers with a high pitch should reach their max thrust at high boat speeds. Essentially increasing the boats top speed whilst making it harder/slower to accelerate from zero. Also consider, that your propeller might actually spin to fast. You might want to consider a larger propeller driven at a slower speed by adding some form of gear box/transmission.
you can use a smaller propeller but with steeper wings
Toroidal propeller
Chafe the hull shape for a better drag coefficient
Maybe make the boat more hydrodynamic and lower the center of gravity to make it less likely to flip over
Toroidal propeller! That's your next upgrade. Also, I need to see these tests again with similar sizes of toroidal props. I predict the same size optimization, but significantly more thrust
You should put 2 propellers symetrically identics to compense the forces made by the motors
A bump in the front of the boat to break the water
You should use a resin printer for bigger propellers that way they come out smooth and work faster
In my opinion i would choose the 2nd propeller 2 because it balances the speed and enough handling making it unique and impossible to flip itself.
This is the guy in all science questions we did when they carried out an experiment
Ngl I'd really enjoy seeing you add British naval cannons from the 1800s
Also play with prop pitch. it will help with either low end acceleration or top end speed
It's about matching the pitch and diameter of the prop to make the motor operate at the optimum RPM to make maximum torque.
Use Turbine instead of propellers. They're way more efficient.
Use a keel to control the direction
Multiple propeller set up means the two rotating forces will nullify each other, that helps with stability
You should make a graph using excel and plot the propeller diameter on the x axis and the thrust on the y axis. If you extrapolate the curve, you can see exactly what radius of propeller will give you the most force before it starts to lose power
But two propellers and do like a tank and use each one to move to one direction and both to go straight ahead/ try making it more aerodynamic
Those propellers are great they would work better if they were just smooth down a little bit more. that's some great work
That boat needs bilge keels and a slimmer stem for increased stability and decreased wave resistance, which ultimately makes a more stable and faster vessel
Bro my UA-cam is crazy it goes from wholesome to horrid ahh temu ad to this dude making a boat
Can you try printing toroidal propellers? They're a recent kind of innovation and they're quiter, produce less wake, and are more efficient.
they are quieter, not more efficient. they create less thrust than regular props
If you make the Hull sit deeper in the water, you'll get more stability. kind of like a fishing kayak compared to a river kayak. You can do this by adding some weights to the bottom to make the boat a little heavier. Another thing you can do is make some little outriggers so it can't flip
You should balance the props with an rc prop balancer and the blades need a more aggressive angle.
Your boat would improve by having a "underwater nose" and body it will stabilize the fourth propeler and might also help if you use two propelers instead. Which should be spinning oposite of each other. Also dont forget to put some weight underwater which should not change with the movement! Soo no water or sand or grains you need actually ballast there.
Add some small fin at the bottom to redirect the flow of water making the boat go straighter as well as a small fin to make your boat turn when you wanted to
You should put a v12 and a twin turbo in that thing
Consider some shaping to allow more waterflow to the prop
You should add-on floats on both sides to make it float better and increase stability And on those floats on the side you could move your propellers there for better turning
A propeller for each float
A great example that bigger doesn't always mean better. Good job liked the video.
Here’s what I would recommend: use a higher Kv motor, that one is wayyy too low to efficiently use one of those props. If you use a higher Kv motor, you will have less torque (you’re not even barely using the torque this motor has) but a higher top end RPM.
You should zero the scale right before thrust test on each propeller so you only get the thrust not the weight of the wood
You should make propellers slightly smaller and larger than 3 and see which one works better. Then keep doing that until you find the most efficient propeller size. Then do it with different sized/weighted vessels. Do it all the way up to an oil tanker and revolutionize the marine industry. Good luck!
You should really print some higher quality ones for boat propellers to be efficient. It is really really important for them to be a smooth as possible and as balanced as possible for the best hydrodynamics and probably use some sandpaper
Its depending.small prop is for faster acceleration while big prop is for higher top speed
Use Is tubes on the inSide So that any water that gets inside can be emptied out and create Slight propulsion Automatically
Put a tube under the center of the boat with two angled cuts on either side to let side water rush through as well. Put this in line with the front of the propeller, and it should (i think) create more of a jet like effect.
Propeller three seems like it's a perfect middle ground.
Add a flamethrower
Have 2 propellers instead of one.
- If you have them at the front and positioned off either side, you would have better and tighter control during movement and more stability when accelerating.
Prop 4 will have the highest top speed as water resistance gets less the faster you go 😊
Next upgrade: put ww2 landing forces inside
Honestly it depends on the KV of your motor, not the size of the prop. Also, nice boat
Add Wings/flippers to the sides for move flow and add fans on the wings for minimum dragback
I have an idea that came from military helicopter engineering that could make the stronger rotors more stable. Twin rotors. Take a rotor place it put another behind it, flip it and make it turn in the opposite direction with the same ammount of power to make the inertial forces balance out and the thrust reach twice the normal level.
Add a curved roof for aerodynamics, but make sure the tol of the curve is very flat, then add 40mm cannon
I advise you to use propeller 1 but with a sharper blade. You also need to make the front of the boat so the boat doesn't have resistance.
now you need to make the front end more streamlined, should help with control and flipping issues as well as speed
you should add a second propeller that is spinning in the opposite direction so that it will be more powerful and wont flip over
Smooth the propeller, Add some sand for weight, ajust the pitch of the motor up a tad. If your eager enough, Make the frount of the boat more if a tringale shape
Make it have control surfaces so it will help you turn better
The boat's look reminds me of a Higgins boat landing craft
y'know the small weight thingy at the bottom of yachts? yeah, use that to balance the boat
Thrust is a force (as much as i have studied physics) so it should not be stated in grams. 2800g=2.8kg now, F=mg
Thus, F≈2.8×10N=28N
That’s not the only problem. The thrust-measuring rig doesn’t give the thrust at the prop, it reads approx 3x the actual thrust. Principle of Moments and all that.
You should put jack and rose at the front when rose goes, "jack im flying."
The force is actually 1/2 what the scale is reading, because the boat has torque
The roughness of the 3d print is also a big factor here I'm certain
Make it use a tiny 2 cylinder 2 stroke boxer engine for power. And maybe water jets?
Now we need the smallest propeller
Use buoyant materials on the bottom and maybe on the sides to make it harder to flip
Maybe look and sanding and smoothing propellers for better air vortex so it pushes more straight
Make it have stabilizers like in ships to make it ease out in waves
There is a motor power to prop size ratio. P4 was bigger but the motor didn't have the power to turn P4 at the same RRM as R3 to push the water. NOW THEN... P4 MIGHT go faster as momentum is generated. This is not examined in your test.
You should swap out the 3-blade prop for a 4-blade prop. 4-Blades are more efficient and make better use of the available horsepower.
This is the most insightful comment section I've ever seen
If jou put the propeller horizontal with the water surface jou will have more control
Try more propeller wings or some hydrodynamic improvement in the front of the boat
Maybe it flipped cuz of the shape, it’ll probably go faster and be easier to control if it’s more streamline and aerodynamic
You could try making it a hydrofoil boat...
Try adding a frictional less layer at the bottom of the rv boat and if possible add a small hydrofoil
Give it some ribs on the bottom, they help keep it straight until you want it to turn
Thrust is usually measured in Newtons
You should do two propellers. It will make it stable.
Awesome armor and some more sodas and some fishing gear
You can smoothen the propellers for better efficiency
the biggest Improvement you can make to those impellers is improving the geometry and the print quality cuz currently those things are going to have more drag than a gay bar in Vegas so either send them down and put a filler primer on it and do all that stuff or buy a resin 3D printer or use a service to have them printed in resin
you should use s co2 canister as a nitro
You gotta add more blades to the propeller so you can generate more thrust at lower RPMs
use a 4 bladed propeller, it has less cavitation and should be more efficient
Sand down the propellers so there isn’t as much friction with the water as they’re spinning. This should free up some torque
Miku Miku, You can call me Miku
Blue hair blue tie
hiding in your wifi!
Motors have a power curve. Propellers need to be matched to that curve.
give it a piston engine, using hydrazine as fuel, and an even bigger propeller and increase the hull size to support the added weight, also more length to make it more stabile. trust me, its going to go like a rocket on water :)
You should ad a fin at the bottom that stabilizes the boat
could add a top and weights to stabilize the boat and prevent water from getting in
a v style hull and some more length would go a long way to making the boat more controllable