Help me tune my stock Motley Crew please

[Crusty128]

Hi

I ve a stock MC, it is running with 2 lipo's 2s, I just upgraded the flex and the coupler since I lost the stock one in a lake...

My concerns are about the strut height (if strut is the right name for this part), and how far I should install the batteries to the rear.

Here are some pics, I hope you could help me, I ve done some research but all the answers I could find are experimented users oriented...

First, does it make any difference to put the batteries to the inner position or to the outer position?

ImageUploadedByTapatalk1368659020.551171.jpgImageUploadedByTapatalk1368659039.088762.jpg
Should I install them a bit more to the rear ?

ImageUploadedByTapatalk1368659112.332291.jpg
How about the alignement of this driveline ? I have nothing to compare since I am new in this hobby.

ImageUploadedByTapatalk1368659166.107504.jpg
ImageUploadedByTapatalk1368659196.564503.jpg

And what about the strut height here ? Is it ok? I ve just raised it a bit since I ve seen that the boat could be faster.


Thank you for your help guys

[Heaving Earth]

yeah raise it up man. when you put it on the table the bottom of the strut should be 1/8 - 3/16 gap between the table and strut. you are keen, most people wouldnt have figured that out. batteries about 30% lenth of the hull but try em both positions.

[Crusty128]

Something more like this?






Thanks !

[Heaving Earth]

Yup

[Crusty128]

Thank you! And what about this driveline alignment ? I have heard that this matter on overall performance

[sanyijr]

Crusty, you need to align that better. Bend the copper tubing a little up so you don't rub on the drive line. Straighten to vertical the rudder as well. And move the packs back. i run my 5000mah packs all the way back to the little bulge rx ridge... Also, I have about 2-3-degree tilt on the strut, so the boat rides a bit looser... Do not be surprised though if out of the hole, you are a bit slower, but once your prop bites, you take off! Having your rudder tilted that much will give you more bounce in the turns. If you have only a few degrees tilt, you are ok to give slight lift up, but too much and you will introduce bad bouncing...

And if i recall correctly, I have about 1/3 inch clearance on the strut... I started at 1/4 and kept raising it, till top speed declined.... (this is with a X640 prop)

[Crusty128]

great help ! MAAAAAANY THANKS guys,

I tried the boat this morning, just set up like you can see on the pics I posted yesterday (I did not see your post SANYIJR...) and just before I flipped it () I can tell you that it did not go faster than before.
Everything look pretty much the same except acceleration when trying to get it out of the hole. it was slower, like cavitating for 2 seconds.

So I'am going to raise the strut a bit more, move my packs more to the rear (this morning I did so but just 3/4 inch from stock, I understand thaht I can do much more), straighten to vertical the rudder as well, bend the brace tubing, and I should be all set right ?

What prop would you advise me? I'm using the stock one at the moment.

[sanyijr]

Crusty,

How did you flip it? Did it blow over or roll sideways and catch a sponson? As for props.... It is advisable to have a few... But for recreational setups, typically a X642, X640 (as I have it) and the Grimm Racer equivalent or some have gone with the X442 or X440... Most common however is the X642 and the Grimm Racer (42X55) I believe....

That cavitation is typical till it gets on plane... And make sure your strut angle is neutral to +2 or 3 degrees (plus indicates that you are angling the thrust from the prop to raise the bow. So 0-3 degrees at most. Otherswise, too much air under the boat and you blow over....) But if all you did was move the packs back and no strut height change from above, i would not expect more speed really. Have to loosen up the hull, i.e. raise the strut to reduce the resistance and contact surface area on the prop. Other thing is the plastic props deflect and bend at high rpm and under load, so your speed increases are somewhat limited. Still definitely do it, but your "sweet spot" will be hit when COG and strut height/angle are ideal...and then topped off with a well sharpened and balanced (S&B) prop... Check through this forum and see the props most often used with your esc/motor... But I would NOT go with the M series props as some do... Just my opinion, but this is really pushing the limits and if you are still on the learning curve of setting up the boat?..... Looking for trouble...

But also remember, if/when you change the prop, you may have to re-adjust the strut height...probably different diameter and pitch prop from stock, so different behaviors.... With the metal props, you can usually go a bit higher on the strut, since you have no deformation of the blades, but you are talking a mm or 2 at the most....

Do read the furum though... tons of great do's and even the don't's... GL HF..

Sean

[Crusty128]

You re so helpful to me! Thank you for taking the time to explain me how things work together.

Again, thank you Sean.

[sanyijr]

No worries... But please....read the MC forum... so much info to see and read....and have fun :)

[sanyijr]

Oh and I just noticed...your picture with the tape measure showing the strut height: that picture looks like you have negative angle on the strut... Might not be the case, but the pic looks like it.... This will push the nose down and make your run the hull wet. (so slow and ...well, slow) And it will make you hook the nose in turns. So make sure it is at least flush with the bottom of the hull if not a bit with the front of the strut up (prop end down) this would lift the nose a hair and keep the hull up out of the water a bit in turns....

[Crusty128]

Mmmh not sure to understand very well. Can you draw a line on my picture to show me how my strut should be ?

Thank you !

[Crusty128]

How and it flipped while turning, it flipped really easily ! I was going slow... I did just a u -turn and flip!!!

[mtbenjamin77]

I just setup a motley crew for one of the local guys. Batteries all the way back start with the strut at 3/16 above sponson bottom with 0 degree trim. Run a detounged x645. Move the strut up 1/16" at a time till speed decreases then back down 1/16. After you set the strut at the first setting mark the strut at the bracket with a sharp awl or any tool to use as a reference point. If you need a prop I have several that work good on the MC. Happy boating my friend! Feel free to pm me if you need any thing. The motley is a fast and fun boat right outta the box with simple tuning. Cheers

[sanyijr]

MTB,

You are running a 645 on stock esc and motor? Seems big... (and I know...that is what she said...)

Crusty,

the MC tends to roll over at sorta slow speeds, the inner sponson catches and then the boat rolls outward... This is also more probable if your CG is too far forward and your stut angle is negative, so the thust of the prop pushes the nose down.... Moving the batts back is a must... Strut angle? do a search for it... I will post a pic if I have a few more free minutes...

Sean

[mtbenjamin77]

Yes a modded x645 on the stock setup runs near 50 mph

[Crusty128]

Hi guys !


What would be the better option:

replace my prop by a X6.. metal one OR try "soft" 3s batteries that are 20C-40C 5000mah ? or do both.

My guess is ESC won't take 6s, even if discharge rate is not very high.

[Crusty128]

Bump to the top

[bmd2k1]

We just acquired a used MC for our Elks lodge from a local RC Boat racing club...that run's on our lake.

Wondering what the best prop choice would be? I see x645 or 42x55 (which we bought previously - sharpened and balanced for our SV27).

Boat is stock..except the water intake was moved to the rudder.

thanks in advance...

-Brian