Word of advice on props, going down a pitch with more blades makes one big of a difference. Going from a 3 to 4, need to decrease 1 or 2 pitches with same diameter. Will never get out of the hole. That 4 blade is also a cleaver prop, it’s desgin to lift the back end at high speed. The 4 blade is too high of a pitch and will not allow to plane. If propped correct. A 4 will get out of the hole eaiser and stay on plane at lower speeds, hold in turns. Can be the same speed as a 3 but 2-4 mph less. 4 would be alot more stable. Just have to find the right pitch and rake
40 years ago a friend was running a 13 ft V hull FE class with a modified 3 cyl Merc putting out about. 100 hp. He ran in the early 80's on a courses. Spinelli was his prop, a two blade. I remember asking him why just two? He told me one blade was most efficient but you couldn't balance it. Looks like he was right after all these years. Great test!
I was thinking of doing a test like this myself. Thank you for saving me some money. I noticed a decent amount of cavitation with a 3 blade 1.6 pitch prop I used on my Blackjack42. Once it gets up on plane, the boat takes off like a rocket. Getting out of the hole is a little troublesome because of the cavitation. I would not have guessed a 4 blade prop made the boat practically useless as many full size boats use 4 blade props. Stern drive and outboards alike mostly use 4 blade props. Great video. Thanks
what exactly causes the cavitation? motor gets bogged down like a car in high gear having a hard time going up a hill??? i tryed 2 blade props on a boat...stock boat does 22 mph lots of power out of the hole...than i tried a much higher pitch same diameter and i got lots of cavitation but once boat got up on plane around 3 meters it took off..top speed was around 33 mph... than i found a prop that was higher pitch than stock but slightly less pitch and blade size than the second prop which had cavitation...Its works real well hole shots were still very good and top end seems to be 30 mph... this is a tiny 14'' boat so it looks as fast as a 30 '' boat doing 50 mph... thanks for any input you may have...
I've always herd a single blade would get the best bite, better than a 2, 3, 4, 5 blade, as we all know a single blade would never work due to balance issues Personally I've always had best performance from 2 blade props topend wise anyway, 3 blade out the hole.. Where in the world did you find a 3/16 4 blade? I want one! 😆 You may have better luck with the 4 blade on a different hull type? Cool test!
In aircraft use it has actually been done where a single blade propeller is used - the other side is mass-balanced so a single blade aero prop can work but I'm not sure about on a boat.
4 blade =0 dam boats really do your head in. Great test. Those detounged props you sell are great. Don't even bother using the proboat props , need to upgrade a few TFLS after this outboard boat is done.
@@RCBoatBitz would be good to show you but no time for anything these days. Have to make a windscreen channel , inner cowl and hinge pillars for the wife's impala. Never buy a car sight unseen or send my idiot know it all father in law to look at it ha,ha, . Looks like they pulled it out of a paddock, blew a coat of black 2 pack over it and new interior then sold it. Had to rebuild it, plenty of flippers doing this now. She's lucky I like big old Gms and they do drive and handle so well. Can't even work on my old Chrysler regal wagon. The Chevy was supposed to be fully restored ha,ha,
@@RCBoatBitz We bought Datsuns cheap in the 80s and bush bashed them. They were great cars and we couldn't kill them. If only we knew they would be worth so much and become rare . Just hard to weld the thin metal but well worth building one. Mates dad got a cheap 260 z t top , it went great ,kept up with a 318 valiant . Worth a fortune now.
good day to you sir, is it ok to have 3 blades of 45mm in 3670 1900kv motor? then 3s or 6s battery. won't the motor burn when set up like that?I hope you will notice. thank you
Ever been in a big power performance boat with 5/6 blade props? They do the same thing, you need to ease into it. You can't just hold it WOT and hope for the best, lol.
Obviously i was trying every way possible to get it to bite until the end when i gave up and held it flat. Its quite common that real size boat stuff doesnt translate in the scale world
@@RCBoatBitz well, is interesting, you ma may be right for deep-Vs certainly not for hydros and co. (..) the true issue with 3 blades you need to change the hight of the struts, since it needs more "air", otherwise you experience what you are saying (..) accordingly the fine-tuning is more complicated because of the related hydrodynamics (..) in reality they run smoother and push more water of a 2 balde prop (..) at least this is wat you experience at the German SAW, where people are very fast, I mean above 200km/h (..)
Word of advice on props, going down a pitch with more blades makes one big of a difference. Going from a 3 to 4, need to decrease 1 or 2 pitches with same diameter. Will never get out of the hole. That 4 blade is also a cleaver prop, it’s desgin to lift the back end at high speed. The 4 blade is too high of a pitch and will not allow to plane. If propped correct. A 4 will get out of the hole eaiser and stay on plane at lower speeds, hold in turns. Can be the same speed as a 3 but 2-4 mph less. 4 would be alot more stable. Just have to find the right pitch and rake
The whole point of the video was to show the difference running the same diameter and pitch changing only the number of blades
40 years ago a friend was running a 13 ft V hull FE class with a modified 3 cyl Merc putting out about. 100 hp. He ran in the early 80's on a courses. Spinelli was his prop, a two blade. I remember asking him why just two? He told me one blade was most efficient but you couldn't balance it. Looks like he was right after all these years. Great test!
Haha nice!
Please ask him what motor he used. I have a 1980s 3 cylinder mercury 2 stroke 60 HP that weighs around 90 kg...I want to tune it..
@@crashtestdummie67 Sorry bud. I haven't heard from him in 40 years. I moved 3000 miles away from him.
I was thinking of doing a test like this myself. Thank you for saving me some money. I noticed a decent amount of cavitation with a 3 blade 1.6 pitch prop I used on my Blackjack42. Once it gets up on plane, the boat takes off like a rocket. Getting out of the hole is a little troublesome because of the cavitation. I would not have guessed a 4 blade prop made the boat practically useless as many full size boats use 4 blade props. Stern drive and outboards alike mostly use 4 blade props. Great video. Thanks
what exactly causes the cavitation? motor gets bogged down like a car in high gear having a hard time going up a hill??? i tryed 2 blade props on a boat...stock boat does 22 mph lots of power out of the hole...than i tried a much higher pitch same diameter and i got lots of cavitation but once boat got up on plane around 3 meters it took off..top speed was around 33 mph... than i found a prop that was higher pitch than stock but slightly less pitch and blade size than the second prop which had cavitation...Its works real well hole shots were still very good and top end seems to be 30 mph... this is a tiny 14'' boat so it looks as fast as a 30 '' boat doing 50 mph... thanks for any input you may have...
So the four blade was a no go. Good to know , thanks for sharing bro
No worries
I've always herd a single blade would get the best bite, better than a 2, 3, 4, 5 blade, as we all know a single blade would never work due to balance issues
Personally I've always had best performance from 2 blade props topend wise anyway, 3 blade out the hole..
Where in the world did you find a 3/16 4 blade? I want one! 😆
You may have better luck with the 4 blade on a different hull type? Cool test!
I have another one like the one in the video listed on the website if youre serious
Thank you very much.
In aircraft use it has actually been done where a single blade propeller is used - the other side is mass-balanced so a single blade aero prop can work but I'm not sure about on a boat.
Wow id love to give that a go!
4 blade =0 dam boats really do your head in. Great test. Those detounged props you sell are great. Don't even bother using the proboat props , need to upgrade a few TFLS after this outboard boat is done.
Id love to see pics of youre twin outboard build, you should consider doing a you tube series on each step of the buikd, i would watch it
@@RCBoatBitz would be good to show you but no time for anything these days. Have to make a windscreen channel , inner cowl and hinge pillars for the wife's impala. Never buy a car sight unseen or send my idiot know it all father in law to look at it ha,ha, . Looks like they pulled it out of a paddock, blew a coat of black 2 pack over it and new interior then sold it. Had to rebuild it, plenty of flippers doing this now. She's lucky I like big old Gms and they do drive and handle so well. Can't even work on my old Chrysler regal wagon. The Chevy was supposed to be fully restored ha,ha,
That sucks, i bought a datsun 1600 project sight unseen a few months back, but all datsuns are full of rust haha
@@RCBoatBitz We bought Datsuns cheap in the 80s and bush bashed them. They were great cars and we couldn't kill them. If only we knew they would be worth so much and become rare . Just hard to weld the thin metal but well worth building one. Mates dad got a cheap 260 z t top , it went great ,kept up with a 318 valiant . Worth a fortune now.
so are all these the same dia and pitch??? did the 3 blade have better punch out of the hole than 2 blade... i can't tell from the video...thanks
Yes all the same dia and pitch. 3 blades will always get out of the hole better
That's bizarre. Most full size boats have multi blade props.
What is the model of GPS you use please.
garmin etrex
I would of liked to kno what the battery voltage was at the change of each prop but good experiment
6s
good day to you sir, is it ok to have 3 blades of 45mm in 3670 1900kv motor? then 3s or 6s battery. won't the motor burn when set up like that?I hope you will notice. thank you
3s battery could run that setup but not 6s, it will burn your esc
I would think you need to use a smaller diameter with the more blades on the prop.
The experiment was purely to see the comparison between same size props
Ever been in a big power performance boat with 5/6 blade props? They do the same thing, you need to ease into it. You can't just hold it WOT and hope for the best, lol.
Obviously i was trying every way possible to get it to bite until the end when i gave up and held it flat. Its quite common that real size boat stuff doesnt translate in the scale world
That's the way to run it last longer less power
IS THAT SPEED MPH OR KMH???
Ks
That is strange....not enough tourqe to pull it?
Cavitation
@@RCBoatBitz then cup it...
What is the boat brand
Proboat
I thought a 48mm prop was to big. You should have been testing with a 42mm.
It was just a test to show how 3 identical dia props compare
There is s golden rule: uneven props run the best …
Ive never heard that but 95% of hulls run fastest with a 2 blade prop, 3 blades are best for low speed acceleration
@@RCBoatBitz well, is interesting, you ma may be right for deep-Vs certainly not for hydros and co. (..) the true issue with 3 blades you need to change the hight of the struts, since it needs more "air", otherwise you experience what you are saying (..) accordingly the fine-tuning is more complicated because of the related hydrodynamics (..) in reality they run smoother and push more water of a 2 balde prop (..) at least this is wat you experience at the German SAW, where people are very fast, I mean above 200km/h (..)
The more blades less diameter
The video wasnt about finding the right prop for this boat, its a direct comparison between the same size props
Interresting... 4 blade that doesn't work at all...!
Maybe on a different style hull things would be different
Why did it go so slow on 4 blades???
Cavitation, blades too close together i guess, 2 blades always fastest