head of the river cat hull thread

[Spot Me 2]

My setup is :

Motor, Feigao 540XL9
Esc , ETTI 125amp
Lipo , 2 x Zippy H 5000Mah 3s
Speed , 58mhp with 42mm K prop hope to reach 60+ with a 42mm metal prop
Time of fun . 6 to 7 min.

I think its best to put all the head of the river cats in one place so i`m in and if you need help just ask.

grtz

Michiel.

Your boat looks great!!! I think you are on barrowed time though. Accourding to FEcalc, that setup is pushing 150+ amps.

[focused]

Your boat looks great!!! I think you are on barrowed time though. Accourding to FEcalc, that setup is pushing 150+ amps.

Thanx,

The ETTI can handle a lot more 150 burst is no problem so i`m not worried about my setup , i have a smaller boat with a 540S7 on 8 cell Nimh and 37m prop on the same esc and also no problem .

I also do not calculate with FEcalc but trust my experience and do al ot of trying with almost no errors and never pussing the limits the first time.


I did a quick calculation with FEcalc and ended at 114 amp so no overheating the Esc.

grtz

Michiel.

[rockwerks]

just curious what is the running weight of these boats?

what does the hull weigh empty

[Fluid]

Accourding to FEcalc, that setup is pushing 150+ amps.

Don't put much faith into FECalc. It was designed at a time when BL motors were just starting and LiPos were not on the horizon. Then it worked pretty well, but today it is only a very rough guide. From personal experience, if the boat is set up well it will draw considerably less than 150 amps. One dead giveaway is the run time: if he runs his packs down to 25% capacity - considered a safe stopping point - his average amp draw is about 40 amps. Peak draws would obvioulsy be higher.



.

[Spot Me 2]

Good to know. I am building one currenty and have the same motor. I guess I will be running 6s.

[Fluid]

Keep to the smaller diamter props and you'll be alright, I'd start with an x637. A 9XL will work great on 4S too, in fact you can use a bigger high pitch prop for more efficiency. In my Mean Machine I ran a 9XL on 4S with an m645 prop and if I aired the boat out enough it would almost hit 50. Actually with today's power a narrow 32" boat is a better 4S boat than a 6S boat anyway (and cheaper too). I hit the mid-80s on 6S in my wider 34" SprintCat at the SAWs, and an even longer boat would have been better.


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[rockwerks]

I have that custom hull of Lonewolfs that I plan on putting in a lehner 6xl, 4s or 12 cells 4600, 200a himodel and start out with a 440/3 33" hull and 10.5" beam balsa hull about the same weight as this FG hull. Im very interested in the setups

[Fluid]

Lehner doesn't make a 6XL (their Basic XLs use a different nomenclature), perhaps you mean Hacker? If so, a Hacker or Feigao 6XL is too much for 4S and that prop - you will be buying new ESCs often. That is really a SAW setup, you won't get much run time while you overheat everything. If you insist on doing it - not recommended - use an x438 or y536 prop.

Really, so many others have tried the 6XL and met with disappointment - why bother? Get a more appropriate motor - an 8XL or 9XL makes a lot more sense.

If you did mean an LMT Basic XL, what Kv do you have?



.

[rockwerks]

Lehner doesn't make a 6XL (their Basic XLs use a different nomenclature), perhaps you mean Hacker? If so, a Hacker or Feigao 6XL is too much for 4S and that prop - you will be buying new ESCs often. That is really a SAW setup, you won't get much run time while you overheat everything. If you insist on doing it - not recommended - use an x438 or y536 prop.

Really, so many others have tried the 6XL and met with disappointment - why bother? Get a more appropriate motor - an 8XL or 9XL makes a lot more sense.

If you did mean an LMT Basic XL, what Kv do you have?



.

one glass of red too many I guess, you are right hacker b50 6 xl, which I would need to run on 6s correct? and I did just buy a lehner basic 3100xl to play with also. going to be an 8 cell stepped mono motor. I do have a nemesis 7xl also. Im new to the boat thing so its all learning to me. I have props from 438 up to 645...about 10 now so I have lots of room to play, and any info is always welcome.

[focused]

you are right hacker b50 6 xl, which I would need to run on 6s correct?

NOOOOOO , dont a B50 XL6 on6s is way too much you`ll end up in 60.000 revs , you`ll need only between 32.000 38.000 for a 32" cat .


grtz

Michiel.

[Tunda]

How does this hull handle in the turns? can you hold it wideopen in the turns?..........

[focused]

How does this hull handle in the turns? can you hold it wideopen in the turns?..........

No not possible , its a cat it will slide away, break out and flip over on full throttle .

grtz

Michiel

[Fluid]

No not possible , its a cat it will slide away, break out and flip over on full throttle...

How much experience do you have racing catmarans? While this particular hull may not like WOT turns (I don't know), all of my current cats thrive on it. A catamaran's forte is excellent turning, I have raced against hydros and won by cutting inside them in the corners. Most - not all - decent cat designs can be made to run fast through the turns without flipping over......if you know what to do.



,

[focused]

How much experience do you have racing catmarans? While this particular hull may not like WOT turns (I don't know), all of my current cats thrive on it. A catamaran's forte is excellent turning, I have raced against hydros and won by cutting inside them in the corners. Most - not all - decent cat designs can be made to run fast through the turns without flipping over......if you know what to do.



,

I`m just answering his question with my experience witn this particular hull ,

How does this hull handle in the turns? can you hold it wideopen in the turns?..........

You just cant go 50 to 60 mph and make a turn at that speed, if so i like to see that on video , you have to step of the throttle and slow down .
Maybe a twin-drive handles it better then a single drive i dont know but believe me i smashed my cat arround the corner and it didnt like it .



Michiel,

[rockwerks]

NOOOOOO , dont a B50 XL6 on6s is way too much you`ll end up in 60.000 revs , you`ll need only between 32.000 38.000 for a 32" cat .




grtz

Michiel.

LOL I guess I needed to use this