MHZ Mystic 1380mm build

[Alfa Spirit]

That is what I told you before, don' t be afraid to run high RPM.
You must have 35000 RPM unload for a good acceleration and high speed, especialy with a catamaran. And don' t forget that the motors you choosed are heavy.
Forget 10S batteries and go for 12S, but I think it won' t be enough...
On my 50" FOUNTAIN P1 the setup will be 4092 - 930kV motors and 10S for each one, The motors are on the way, the weight of one motor is 500 grammes.

If you order the SKYRC Proteus X520 The setup can be ok with 3D wiring - 1280kV and 8S batteries, 37888 RPM unload.I hope this is what you order... not the X524? So why 10S?

[MrUnlimited]

I have been racing 1/8 hydroplanes for many years: our gas engines and nitro engines turn only 20k-25k rpm. Not fast huh? These boats run over 85mph! Why? Because of the pitch on the prop. It is not like the more rpm the faster you go like rc cars but we turn a LOADED 10k-11k rpm on the prop and play with the pitch. By using lifting props we achieve high speeds. So 730KV on 10s gives me more the 30k rpm unloaded with the right prop it gives me enough speed. A full lipo cell delivers over 4 volts, so 10s delivers over 40volts

[MrUnlimited]

Didn't make any cuts before gluing. I just glued them in, and then cut to size after I measured the distance. I used a flex cable to measure. Feed it up till it hits the motor shaft, then apply some tape on the prop end and use that as a guide.

Kent I run square drives L&R in my mhz138. That is why I have to cut them first but I am gonna look where the cg and the dtermine how much I have to cut.

[drwayne]

I have been racing 1/8 hydroplanes for many years: our gas engines and nitro engines turn only 20k-25k rpm. Not fast huh? These boats run over 85mph! Why? Because of the pitch on the prop. It is not like the more rpm the faster you go like rc cars but we turn a LOADED 10k-11k rpm on the prop and play with the pitch. By using lifting props we achieve high speeds. So 730KV on 10s gives me more the 30k rpm unloaded with the right prop it gives me enough speed. A full lipo cell delivers over 4 volts, so 10s delivers over 40volts

Hi. I run twins... 12S to 730Kv, after batt/esc/motor efficiency losses expect <80% down the shaft.
Higher voltage equates lower amp draw....high amps will cause grief quicker than high voltage to the electrics
I note here that US have 10S voltage limit for racing.

Kent I run square drives L&R in my mhz138. That is why I have to cut them first but I am gonna look where the cg and the dtermine how much I have to cut.

You've lost many forum experts now.... sq drive ? haha
High rpm sq drives get induced vibration that's "hard to shake".
Rarely seen sq collets for FE motors at OSE . the threaded claw / grubscrew type are all the norm.. relocate thrust face from stinger to eng mount...
You would most certainly need extra buttressing at the stinger faceplate for a sq drive setup.
regs
DocW

[MrUnlimited]

Wayne,

I drive in my other boats squares without problems, also my fellow competition boaters swear by them and they run their boats on National, European and Worlds Championships.

[nata2run]

Ok, wow. Ditch the square drives and invest in a high quality MBP collet. You will never regret it. Also you ca t load up an electric motor like a gas. You can load up a gas motor till it stalls. You do that an electric and it will light on fire!!!! An electric motor don't know it's limit, it will simply go on pulling till it burns. That's why we take some pressure off with smaller props. But smaller props need more rpm. So there it is in a nutshell.

[nata2run]

For this size cat a 457 is very common, how ever for very serious setups you can run bigger but also spin them faster. 457 in mid 30k is a good sport setup. To go past 80mph you'll have to be late 30k. 100mph can be achieved in the 40's. I have spun my 457 cut to 52 @ 43k

[drwayne]

Wayne,

I drive in my other boats squares without problems, also my fellow competition boaters swear by them and they run their boats on National, European and Worlds Championships.

Certainly, I qualified my comment by "Rarely seen sq collets for FE motors at OSE".
I used sq for 28+ yrs in nitro ( never ran gas )

For this size cat a 457 is very common, how ever for very serious setups you can run bigger but also spin them faster. 457 in mid 30k is a good sport setup. To go past 80mph you'll have to be late 30k. 100mph can be achieved in the 40's. I have spun my 457 cut to 52 @ 43k

Are you serious ?

I thought this was a serious thread .

sorry.

[jkr]

Question:
A pair of 1527 850kv 12s?
Do you thing it could go fast?

[nata2run]

Question:
A pair of 1527 850kv 12s?
Do you thing it could go fast?

Yeah not bad speed, but super fast you might want a motor that's really up to it. Like a 56 or lehner 3040

[nata2run]

Certainly, I qualified my comment by "Rarely seen sq collets for FE motors at OSE".
I used sq for 28+ yrs in nitro ( never ran gas )



Are you serious ?

I thought this was a serious thread .

sorry.

Yes I'm serious, please remind me again how it works in a 54" hull

[jkr]

My thought
Twin 12s 1527 90+
I thing it is possible also 1kg lighter.

[jkr]

I know lehners but i don't really like them.

[nata2run]

My thought
Twin 12s 1527 90+
I thing it is possible also 1kg lighter.

Yes most likely possible, in a 54" could be risky.

[Chrisg81983]

Kent said:::::
For this size cat a 457 is very common, how ever for very serious setups you can run bigger but also spin them faster. 457 in mid 30k is a good sport setup. To go past 80mph you'll have to be late 30k. 100mph can be achieved in the 40's. I have spun my 457 cut to 52 @ 43k

You said:
Are you serious ?I thought this was a serious thread .sorry.[/QUOTE]

DOC WHAT SO HARD TO TAKE SERIOUS ? How come you are always taking shots at kent ? from what I see he is very knowledgeable, and how I see it he has a faster or actually several faster boats. So how I see it you should be listening to him rite ? Please don't take this personal but I just been seeing you kinda be a **** to him in many posts so I was just wondering what the deal is. You are both smart men lets keep it at that. Thanks