Prop size on a 8XL and Hydra 240 ESC?

[10gauge]

I know that a Hydra 120 ESC is not up to the challenge of running an Feigao 8XL on anything above a 440 prop. However, what if a Hydra 240 ESC was used on an 8XL motor, up to what prop size can one use and still keep within the temp and current limits?... x442, x445, x642?

[Mich. Maniac]

I could be wrong but, feigao xl 540 motors cannot even handle 120A continous. They should be run around 70A max. At least that is what I have read. I have even read they should be run at 60A cont. I see no reason to run a hydra 240 on a feigao motor.

[Mich. Maniac]

Steven has posted some simple numbers here, I even think his numbers on max ratings are a little high. They will take abuse but only for soo long. here is what I am talking about.

http://www.offshoreelectrics.com/fei...tors-chart.php

[Raydee]

I run a 7XL in my rigger and one in my Whiplash both on Hydra 120 controllers and have no problems. If you do plan to use big props just watch your temps or for less than $100 more just get the 240 and have some head room.

[Mich. Maniac]

I run a 7XL in my rigger and one in my Whiplash both on Hydra 120 controllers and have no problems. If you do plan to use big props just watch your temps or for less than $100 more just get the 240 and have some head room.

How many amps do you think your rigger is pulling with 7xl? prolly not too many. I guess it doesnt matter what the specs say. Push 160A through a feigao. its your money!

[10gauge]

Thanks Mich and Ray! I have burned a new Hydra 120 in a Mean Machine Cat with 8XL, 4S2P, and a x445 prop. That's why I thought perhaps a Hydra 240 could give me a safety margin. From now on I am going to delegate my 8XL only to hydro setups.

[Raydee]

How many amps do you think your rigger is pulling with 7xl? prolly not too many. I guess it doesnt matter what the specs say. Push 160A through a feigao. its your money!

My EagleTree logger says I am in the 85-90 amp range with peaks of about 110.

[Mich. Maniac]

Really? that just doesnt seem right. I know your not new to this but sounds like their maybe something wrong with you setup. IMO a 8xl and hydra 120 should be perfect for MM hull. save some money and just use a 9xl with the same voltage and get your 120 repaired. should spin x445 ok.

[Mich. Maniac]

My EagleTree logger says I am in the 85-90 amp range with peaks of about 110.

Then you are right where you should be. As far as HIS setup. pushing a feigao motor anymore than 120A just isnt good for anything. I wouldnt think even on MM hull that amps would be over 100A. Again I guess it would come down to getting it logged as you have done.

[Raydee]

Well in any hull if you are running wet you can draw way to many amps. Cats have a lot of drag in my opinion and unless the boat is up and out of the water you can easily pull some serious amps.

[Jeepers]

I may be wrong but I think even a 445 is to big even for a 9xl now a 442 thats a better choice IMO

[Doug Smock]

FWIW
I ran a wc 8xl in a Titan 29 on 4s2P while my 1515 1Y was in for bearings.
Ran the same prop (640) and the temps were nearly identical. Cells 117, esc and motor around 125. The load on this setup is 128 amps. per Eagle Tree.
The boat was not quite as fast but did well.
NOTE: This is a free running mono!!!

Doug

[properchopper]

This is a good thread; it also lends support to Mr. V's suggestion to start a Setup section where we can share our trials & [costly ] errors

Fwiw, I've run a watercooled CC 80 with a 8XL for over a year now in a OM26 with no prob's [ 12 & 14 cells, lately 4S. ] Keepin' the props small : X637, P 215, lately a X640. The big factor for me is runtime; I keep it short for fun running. Usually never over 3 minutes[ I use a timer]. Heat builds up exponentially so I've learned to limit my "hot setup's" runtime drastically.

I have other Hydra/Feigao setups to share; let's get the "setup section" going !

[ReddyWatts]

I know that a Hydra 120 ESC is not up to the challenge of running an Feigao 8XL on anything above a 440 prop. However, what if a Hydra 240 ESC was used on an 8XL motor, up to what prop size can one use and still keep within the temp and current limits?... x442, x445, x642?

I agree 10gauge. You will need a controller larger than a 120 amp in a cat, if you use a prop bigger than the X440. These motors are rated at 800 watts, but have been run successfully to around 1800 watts. Watch your max watts and temps.

[Jeepers]

also note that a bound up driveline will pull more amps regardless of prop size or how loose the hull is.

Today a club members hydro running a SV27 motor, motor came in at 220 running a x440 2 blade prop.
I think its cause the drive/builder opted to use a S bend in the driveline.

[Doozie870]

"Today a club members hydro running a SV27 motor, motor came in at 220 running a x440 2 blade prop."

[kburrows]

Hey guys, after reading this i relized a few people are running a similar setup that i have, I NEED HELP. I got a brand new Hydra 120 and 8xl setup with two 7.2 nicads' 4500s in series and it is very weak. It works but this system barely got my BJ on plain. batteries are live and prop is x642.

Anyone with this problem and how to fix it.

[Steven Vaccaro]

Hey guys, after reading this i relized a few people are running a similar setup that i have, I NEED HELP. I got a brand new Hydra 120 and 8xl setup with two 7.2 nicads' 4500s in series and it is very weak. It works but this system barely got my BJ on plain. batteries are live and prop is x642.

Anyone with this problem and how to fix it.

Ken please start a new thread.

[SweetAccord]

So here is a hypothetical setup (properchopper) if you may advise or anyone:

Boat: SV27
Motor: Fiegao 8XL
Batts: 12 cells of 4600Mha
ESC: Hydra 120
Coarse: None oval corse, simple back and forth straights.

Would the Hydra be underrated for this setup? I know the prop is the last culprit to determine the setup, so what would be the ideal max prop?

[Stealth Assassin]

What Is the smallest prop you guys run? Any 3/16" stub shafts turnned down to 1/8" for smaller blades???

[Mich. Maniac]

Watts = Volts X Amps. I guess I dont get it. If you should only run a feigao 8xl @ 90 Amps then multiply X 14.8 =1332 thats recommended and still over 800 watts they are rated at. So why run more than 120A esc? if you are running period of what prop @ 120A 14.8V you are running 1776 watts. Thats a ton of power and should spin a reasonable size prop. If you are running too big a prop for that then you should chose a larger wind motor with more voltage to increase watts, and or power.

[10gauge]

Thank you everyone for all your input!

I wish I had used a data logger when I ran an 8XL / Hydra 120 / x445 combination a while back - well, I was only 2 months into this hobby at the time. There were other issues I realized afterward which may have contributed to it's demise, but at that time, the boat was running wet, as Ray suggested. In any case, the "sweet spot" for this hull is having the bottom of the strut at least 1/4" above the sponson. Raising the strut has made a huge difference in temps, current, and speed.

Moreover, I think the MM with 2P might be too heavy for a high kv motor like an 8XL, and that's why I thought that the LV240 might be safer. In any case, I have shied away from jinxing a Hydra 120 ESC with an 8XL in my MM and will save my 8XL for a low hull slip design like a hydro or rigger.

I've been recently running a 9XL/4S2P setup where my temps have been slightly warm on everything. Speeds are as follows: m440 = 41mph, x442 = 44mph, and x445 = 48mph. Ultimately I want to hit 50mph with this setup, and hopefully a m545 or a x642 will get me there...