h&m fast cat

[Fluid]

why??? i think i will try!!!!!

And you should try. Don't listen to those who have not set any speed records, all they know about is "GPS speed". 77 mph is plenty fast but that hull can do it with the right setup. I went almost that fast four years ago on an official race course with an 12-cell cat that was only 26" long. The Agitator looks like it can handle that speed, although it may not be easy.

On 5S your 1950 will need a prop like a v937/3 to reach it's top speed. Don't listen to those who say a 2-blade is fastest - they just read it in some book. It is simply not true and many SAW records prove it, including my own.

The Lehners need high advance to reach top speeds. Again, this is proven on the race course, not in someone's back yard pool with a GPS. The higher the amp draw, the more advance is required with the 2-pole motors. Your amp draw will be over 100 amps to reach your speed goal. Start with medium timing and go up if required.

Set the boat on a flat table. Raise the strut so the bottom of the strut is 3mm above the tabletop and parallel to the table. Run the boat and see how it runs. Keep raising the strut 2mm at a time until it either blows over or the speed drops. Set the CG at 33-34% from the sponson transoms. The boat should run on the back 8-10cm of the sponsons at a small positive angle of attack.

You have to realize that if you want high speeds then you will have to limit the way you run your boat. No more than 3 passes, the bring the boat in and check for high temperatures. DO NOT RUN THE BOAT LONGER unless you have proven it is safe to do so. Otherwise you can overheat your motor, ESC or cells and damage them. That is an expensive mistake.



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[Simon.O.]

"Fluid" aka Jay Turmer IS THE man to listen to when it comes to cats. I know this as he helped me design a very nice cat and set it up to run well given the brushed power that I use. He may not know this but his writings helped me do so.
He has a demostrated history and knowledge of fast cats and will provide real world data of how to get one to run well.
Many people would do well to listen to him.
I have, and will continue to do so as long as he is keen to offer his advice.

[Ub Hauled]

"Fluid" aka Jay Turmer IS THE man to listen to when it comes to cats.

Antonios... try it just like Jay suggested... I think you'll find that it will go over 100km/h
and probably close to your target.

[roussos.p.antonios]

Thank you all for your replies,i realy need them.

[bonewar]

antonios mate what is the size of this cat (length,width,height) thanks mate bonewar.

[roussos.p.antonios]

Antonio's what was the fastest 2 blade prop you use, maybe go back to it and try advancing the timing on the motor to get the speed your chasing , just a thought , as you get to the top reaches of advance the motor and esc become less efficient , the idea being two go back and bump up the prop diameter and pitch to use up your spare amps on low timing, then wind up the timing to give you extra kick. this might help you with a little more speed. bye the way nice boat mate.

the fastest prop i use is x442 and low timing.

[bonewar]

how about trying that prop (x442) with a little more timing, i really liked what fluid had to say about the 3 bladed props(v937/3), so i think that would be another good place to start, be good to compare the 2 props. the maritimo cat i'm building has 2 neu motors with 2000kv each i,m running 2-x442 s,b detongued and cupped, i tried 1 of these props on my sv27 it was faster then the normal x442 s,b. so hope this helps bonewar

[roussos.p.antonios]

And you should try. Don't listen to those who have not set any speed records, all they know about is "GPS speed". 77 mph is plenty fast but that hull can do it with the right setup. I went almost that fast four years ago on an official race course with an 12-cell cat that was only 26" long. The Agitator looks like it can handle that speed, although it may not be easy.

On 5S your 1950 will need a prop like a v937/3 to reach it's top speed. Don't listen to those who say a 2-blade is fastest - they just read it in some book. It is simply not true and many SAW records prove it, including my own.

The Lehners need high advance to reach top speeds. Again, this is proven on the race course, not in someone's back yard pool with a GPS. The higher the amp draw, the more advance is required with the 2-pole motors. Your amp draw will be over 100 amps to reach your speed goal. Start with medium timing and go up if required.

Set the boat on a flat table. Raise the strut so the bottom of the strut is 3mm above the tabletop and parallel to the table. Run the boat and see how it runs. Keep raising the strut 2mm at a time until it either blows over or the speed drops. Set the CG at 33-34% from the sponson transoms. The boat should run on the back 8-10cm of the sponsons at a small positive angle of attack.

You have to realize that if you want high speeds then you will have to limit the way you run your boat. No more than 3 passes, the bring the boat in and check for high temperatures. DO NOT RUN THE BOAT LONGER unless you have proven it is safe to do so. Otherwise you can overheat your motor, ESC or cells and damage them. That is an expensive mistake.



.

Thank you for your reply. the pitch of the v937/3 prop is not to much.
with that prop the esc is in danger.
so it is better to use 3blade prop?
i have set the strut with the same way but only 1mm from the tabletop and almost parallel to the table.thank you for your help!

[roussos.p.antonios]

how about trying that prop (x442) with a little more timing, i really liked what fluid had to say about the 3 bladed props(v937/3), so i think that would be another good place to start, be good to compare the 2 props. the maritimo cat i'm building has 2 neu motors with 2000kv each i,m running 2-x442 s,b detongued and cupped, i tried 1 of these props on my sv27 it was faster then the normal x442 s,b. so hope this helps bonewar

i will try the x442 with more timing but i will try also x642 with low timing.all the props i have are sharpened and balanced .

[roussos.p.antonios]

antonios mate what is the size of this cat (length,width,height) thanks mate bonewar.

the size of that cat is:
Length: 810 mm
total length 910 mm
broad: 245 mm

[bonewar]

thanks for the measurements , the hull is not far off the maritimo in size ,and i do think you will be able 2 reach your speed goals . the x642 is a good prop maybe up the timing on that prop as well . you have got me very interested in the difference of speed of these props so please tell us what happens when you test them. thanks mate bonewar

[roussos.p.antonios]

thanks for the measurements , the hull is not far off the maritimo in size ,and i do think you will be able 2 reach your speed goals . the x642 is a good prop maybe up the timing on that prop as well . you have got me very interested in the difference of speed of these props so please tell us what happens when you test them. thanks mate bonewar

i will try also x642 with timing .the only think that i'm afreied is the esc i don't want to burn it.i have burn c.c240 but i don't know how.i run with it more than 10 times with temps. less than 40deg.
i will tell you everithing when i test them.

[Fluid]

...the pitch of the v937/3 prop is not to much. with that prop the esc is in danger. so it is better to use 3blade prop?...

It depends on whether you want to go 77 mph or not. The x642 will not get you there, and the boat will blow over. You cannot run for more than 3 one-way passes (not laps) or the ESC will overheat. Take my advice - or not....


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[roussos.p.antonios]

It depends on whether you want to go 77 mph or not. The x642 will not get you there, and the boat will blow over. You cannot run for more than 3 one-way passes (not laps) or the ESC will overheat. Take my advice - or not....


.

I will try the v937/3.I want to go 77mph.Please tell me do I have to careful samething special when i try?
thank you.

[bonewar]

fluid , can you suggest a 3 bladed prop for my maritimo cat , i 2 would like to go fast , neu 2000kv 2- cc 120amp esc's, 2- 5s1p lpos the boat will be around 3-3.7 kg when finished . thanks mate sorry to jack your thread antonios but i think we both should listen to fluids comments.