cat samich

so i have been running an octura x472 on my 57 apache. i called abc and asked for there advice. from our conversation they were convinced a 3015/3 would be perfect.

so i head out to the pond armed with new prop and this is what happens

i put the boat in the water and start heading out kinda slow, all is good. so i start to add throttle and the noise goes up and the spray goes all over and the boat goes no where.

so i get pissed and start revving the crap out of it well it starts to move and i say what the hell and floor it. well all of a sudden it jumps out of the water and is really hauling the mail.

well if i back out of the throttle in the turns and it falls off plane it takes a bunch of reving and throttle work but then all of a sudden it will take off again.

well at this point im confused so i bring it in and check the drive dog, collet and clutch and all looks ok so i switch over to the x472 and it jumps out of the water at any throttle with no hesitation.

heres the other thing, when the 3015 is on and it is up on plane its easily faster than the x472 but you can tell its really loading the motor. it doesnt sound like its getting anywhere close to the rpm it does with the 472 prop.

what in the world is happening!!?

cat samich

nobody? im so confused about this. i have been doing some google searching and have come up with no explanation.

Nosedragger

3015 is bigger diamter and much more pitch.

martno1fan

You may need to alter the depth to help the prop loosen up but a lot depends on the engine your running,stock or modded etc.To be honest id go with a 7015/3 that seems to be the prop of choice on these boats with a decent engine.What engine are you runnning?,also another good prop would be the 6717/3 from propshop or elsewhere.
Mart

cat samich

its a 55cc shindawia chainsaw motor heavily modified maybe 7 to 8 hp and gobs of torque

Dockman

I'm no expert but, I would drop the strut and try it.

Justaddwata

My Feedback: (3)

You started another thread asking for advice for a prop to run and got good complimentary advice regarding a prop recommendation/s from Scott and myself. You never acknowledged that advice (so perhaps you read it [sm=rolleyes.gif]). I know I went to some trouble in posting there - I even took several photos for you to compare the props.

You then buy a different prop than what was recommended and start a new thread asking why a prop that was recommended to you by the prop manufacturer does not work. Why not ask the person who sold it to you since it was their advice alone that convinced you to buy it?

While asking advice in no way obligates you to take that advice - not acknowledging it and then expecting everyone to jump at your next question is a stretch.

Your prop is cavitating. First thing I would do is try adjusting your strut (as mentioned by others) since you already have the prop. Might be that you have to deal with some cavitation to get up and running with this prop.

cat samich

i appreciate the advice you gave in the other thread, i did read it, the shop i deal with didnt have a wide variety but did have what the guy from abc props told me should work. i was looking for something for over last weekend without ordering and waiting. again i am super appreciative of any and all advice. i apologize for the lack of acknowledgment in the other thread. i suppose i could have posted this in that thread, i wasnt thinking due to frustration. again i apologize



will it help to get the prop farther away from the transom? or is getting it lower the way to go?

martno1fan

You may need to raise the strut to help with unloading the prop on takeoff but then you may find the boat runs a tad wetter,basicly its a case of testing and retesting different setups untill you find what your boat likes with that prop ,Theres no short cuts its all about getting out there and just trying things but making notes about what you do so you know what did what etc etc.Cavitation out of the hole as they say is something you will get with certain props,some of it you can live with because as you may find out it will be a fast prop,some props wont cavitate as you found out but then will be a tad slower at the top end.Maybe find someone local whos willing to lend you a few props to test till you find one that works best for you.
Mart

cat samich

thanks mart, i wish i had a friend close by that would lend me a few. unfortunately the only person who will owns the lhs and wants 20 to 80$ every time i "borrow" one haha


i was stuck on using a 3 blade due to someone telling me that 3 blades were better for "take off" because they had more bite on the water. seems like i might give up on that and try some more of the 2 blade variety. they seem to work better for this boat. also do you guys think this hull would run better with a different motor or twins? i was thinking about building a cat but i just love the apache hulls, id be happy to just get this boat faster/better handling.

martno1fan

The Apache and Navaho hulls i build run great with a single modded zenoah,the one in this vid belonging to a friend and customer is running 50 mph with the 470 prop,shes faster now with a 7015/3.Nothing wrong with 3 blades once you find the right adjustments etc so dont give up on it just yet .
Mart
http://www.youtube.com/user/riptigary#p/u/3/S2nQzZWz8dc

cheesewizz69

Mart, what do you think about giving that prop a bar cut or texas cut. Should that help his prop unload a bit? Just putting it out there not sure if it would work for him or not.

tropheus29

I have a brand new prop shop sharpened and balanced 6719 3 blade prop for sale. 25 bucks and I paid 55. Beautiful piece if you are experimenting and want to add to your arsenal. shoot me a PM

cat samich

what motor is he running in that hull mart? i was looking at motors tonight and i think i can benefit from a swap seeing as how my motor weighs 21lbs! (i pulled it and weighed it tonight again its a fairly large chainsaw motor that still has alot of the saw still attached to it lol)

im assuming the whole boat should weigh about 20lbs. mine comes in at a fuzz under 40!

dont crucify me just yet for the piggy of a motor, it was in the boat when i got it.

im assuming a pair of stock zen 260s with surface drives and the right props will run circles around what i have now?

here is a video of the boat running the x472, at the end the Colette let loose and i had to tighten before i could keep running, tomorrow i will load the video of it running the 3015. dont mind my friends goofy dog and daughter lol. btw both him his daughter and his english mastif were soaked by the end of this because of my "fly bys" haha


http://www.youtube.com/watch?v=rtaTPRCeJ3M

martno1fan

Hes running a fully moded zenoah 260pum called the zen7 from Prestwich here in the uk its rated at arround 7.3 hp according to the builder and his dyno .Yours doesnt seem to go too bad to be honest but yea a lighter motor like a good zen or even two would def get her moving better.Personally id keep it simple and opt for a single modded motor.
Mart
ps nice dog

Doubledog

My Feedback: (48)

You know a fun solution is to find a buddy that has a prop box full & try them after going through different setups.

cat samich

please explain what these cuts are you speak of

cheesewizz69

It's really too much for me to type out but if you look at FAQ section you will find lots of info that should get you started. In particular http://rcboat.com/prop.htm Backcutting Props as you will see I misspelled "Bar Cut" it should be "Barr Cut" LOL

here is the link to faq page in the RC Boats General Discussion section;
http://www.rcuniverse.com/forum/m_3120686/tm.htm

martno1fan

The simplest and easiest way to cut a prop is to simply remove material from the traling edge of each blade ,this reduces the surface area without changing the diam thus loosening up the prop a bit as theres less blade area so the motor finds it easier to spin .Leos ideas will do the same kinda thing,but remembr if you ever do alter a prop it needs balancing again .
Mart
ps Leo whats a texas cut is it anything like a Glasgow Kiss

cheesewizz69

LOL..... As soon as I type this I'm sure someone will correct me... (cut and past from some notes I saved)

A Texas-Cut, is sharpening the leading edge/ > More specific/ > Remove blade material along the leading edge/ > Contour or cut-back the leading edge, from the blade tip > hub. Instead of a gradual blend in the leading edge, cut it at a straight angle from the hub. This reduces the overall size and Dia. of the prop. without removing pitch! This generally improves prop efficiency, and helps to un-load the motor; while not greatly changing the Aspect-Ratio > Pitch divided by Dia.

martno1fan

Thanks for clearing that up for me mate [sm=idea.gif]

cat samich

what kind of speed/performance could i expect from a single rcmk?

martno1fan

I would think arround mid to high 40s maybe more,im sure theres guys on here running them in these kinda boats that can chime in with there experience with the rcmk evo.If the rcmk inline twin has had its teething problems sorted out then that would be an ideal choice in my opinion,the price is very good for the power your getting.
Mart