twin motor cat motor suggestions

[ozzie-crawl]

i have brought another 32" cat and would like to try a twin motor setup. was thinking two ammo 2300s on 4s as they will be easier to mount than xl motors. any advise appreciated

[ReddyWatts]

Be sure and use different cables for the counter rotating props.

http://www.offshoreelectrics.com/proddetail.php?prod=oct-oc150L-24c

http://www.offshoreelectrics.com/proddetail.php?prod=oct-oc150R-24c

[kevinlew211]

Mega Acn22/45/1e, 6poles, 2100kv, 60+mph with right prop, :buttrock:

[ozzie-crawl]

thanks reddywatts thought about the left-right hand props but not the cable. i have seen some pics of cats with both props the same would that be for oval or have they stuffed up. i already have a 32" cat with a single 7xl on 4s that is around the 100klmh mark but want to do a twin as i like to build. do you think 2 ammo 2300 on 4s will be enough or should i go L-xL. ammos will be easier to fit as the sponsons are low profile.

[bonewar]

Ozzie mate, best way to go is, figure out what battery's you are going to use , then match a motor to the batts, then esc to that. props come later. have a look at this pic , sort of explains what I'm trying to say. :rockon2:

[ozzie-crawl]

yea have that graph saved in my computer for awhile very handy. batteries will be 4s 20c 4500s. have just been reading your twin cat thread must be one of the nicest builds ive seen.is there any formula as to motor placement/ % from transom. thanks scott

[bonewar]

thanks Scott, mate my motors are about 15cm from the transom, I've placed them there to give myself 2 options for lipo placement, in the spoonson or up on the tunnel section of the boat. the steps in the hull are a good place to start , forward or back, it's really up to you. good way to sort it all out is get everything together and place it in the hull, figure out where the cog is and go from there.cheers rick:rockon2:

[Simon.O.]

Is there any formula as to motor placement/ % from transom. thanks scott

This might be a big hole that I dig for myself.

As far as any setup is concerned I would place the motor as far forward as I can within practical limits to ensure that the drive line has a smooth a run as possible.

Look at an OB with the motor vertical and then a 90 deg bend to the prop, I have one so I know that it is not optimal. For an OB Tunnel there is no option.

For a Cat on twins I would suggest that you will have some room to move these motors well enough forward to get a nice relaxed drive line and get good efficiency.

The whole argument of counter-rotating props is long and inconclusive to me, especially if you are going for oval running.

Flex is good if you have to go for an aggressive bend but you may want to look at wire drive especially if you can get a smooth run from the motor to the prop.

Your boat
Your money
Your call

My suggestions.

[ozzie-crawl]

bonewar: yea was thinking of putting everything in and seeing were cog was and going from there just thought i would ask just incase there was some magic number.hopeing to put the lipos in the sponsons to keep the weight down low. i havent got all the parts for this project yet will be acouple of months till i finish it but i have motors and escs so i can make up motor mounts and work out cog. simon.o. will be running oval. what i was thinking was if the boat rolls in a bit as u turn and the out side prop comes out of the water a bit would the inside prop if going in the opposite rotation cause it to try and push the boat in the opposite direction ( if that makes sense) will be going for flex as i will be useing sv27 stingers because they have a small mounting area and will give me the distance i need from the prop to transom. thanks scott

[Tony]

i have brought another 32" cat and would like to try a twin motor setup. was thinking two ammo 2300s on 4s as they will be easier to mount than xl motors. any advise appreciated

There is a member on this forum with a 32" cat like mine, but his with twin motors setup. A10 - 4S1P config. Twin Ammo 36/56/1800 motors. Maybe he could give you some more infos. Take a look here .

http://gallery.offshoreelectrics.com/displayimage.php?album=lastup&cat=0&pos=1

[ozzie-crawl]

thanks tony: had a look at that picture and it is the same hull i have although mine came just as a bare hull and i have one of these with a single xl.