New Builder: DYMotorshop 750mm Mono - High Deep V "Jack"... watch me learn!

[autolex]

Hello everyone.

I decided it was time to pull the trigger on a hull-up build; I wanted to build a real carbon self built monster.

I researched quite a bit: I wanted something that could crash through light waves here on local lakes in Saint Louis, and still capitalize when it's flat.
So, I figured enough playing with plastic hulls and buy into a real world "all 'rounder". I selected this hull and plan on running it with 6S power that I already have great batteries for and chargers for.

Meet "Jack". as in; "Jack of All Trades".

This is a DYMotorshop 750mm "High Deep V" Carbon Kevlar Hull. I'll be taking setup guidance from builds like the (OSE Carried) Delta Force 29.

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Goals:
60-70mph in SAW/6S mode
40-50mph in "4S Basher" mode (aka "choppy water mode")/5min runtime per 4S (graphene) Pack

Parts already decided:
6S LiPo Power (existing EC5 Fitted 3S 50C 5200mah packs)
4S Graphene Power (existing EC5 Fitted 100C 5000mah packs)
36mm "power" motor (ordered a SSS 3682 1650kv this morning)
OSE 36mm fully adjustable carbon motor mount (ordered this morning)
OSE 150A Raider ESC (ordered this morning)
Spectrum STX3 Radio/Reciever (already have)
Carbon Battery and ESC Trays (ordered this morning)

What I need help with:
How do I decide on a flex shaft? how do i measure this? what parts do i need?
How do I decide on a stinger setup? or should I do a strut?
Should i consider a flood tube?
How do i determine motor placement?

I've never built a RC Driveline on my own, how do i decipher shaft size and prop shaft size and teflon tube size vs stuffing tube size and more!?

How do i pick prop sizes? I figure i'll have a basher type prop and a top speed prop, how do I pick these? (I have some CNC props in 40mm, 42mm and 43mm to start)

Thanks in advance!

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Alex Narconis
(background in electronics/computers and fiberglass, mostly new to the drivetrain part)

[koen]

for flex shaft 3/16 ,stinger and or struder(that's a stut and rudder in one) OSE has it all and propshaft also 3/16 for a big choice of props (stick to ABC or prather and octura)start with 43mm and then go a bit bigger

[LibertyMKiii]

How do I decide on a flex shaft? how do i measure this? what parts do i need? Based on the power and speed you are talking about 3/16 sounds like the best option.
How do I decide on a stinger setup? or should I do a strut? Stinger seems to be the way most go with Mono's. I'd look for one that has vertical adjustment if possible. Struts ultimately allow for more adjustment.
Should i consider a flood tube? I would do a sealed flood tube/box setup. Should be able to look at some other builds on the box design.
How do i determine motor placement? Use the 1/3 center of gravity method. Place the motor, ESC, and LiPos in there. the other consideration is the flex shaft/tube angle. Generally putting the motor further forward will help allow a mild angle for your flex shaft. You also want to check with the boat manufacturer and see if they have any sort of setup sheet to help guide you... Make sure to setup the boat in a way that you can move the LiPos forwards or backwards to further adjust the center of gravity.

Octura X series props have been really good on my Mono and that is what I would recommend. I have a Dasbota x series prop and it is extremely efficient.

[jkflow]

You can always take a peek at Oxidean marine to get a general idea and probably some details. I believe it's the identical hull.

[LibertyMKiii]

JkFlow's advice above is a great point.
Looking at the pictures of the Oxide marine Dominator in carbon (that model had better pics)
It appears he uses this setup butted up against the transom https://www.offshoreelectrics.com/pr...rod=tfl-523b69
Then has an battery tray in front of that down the center.

[autolex]

Great point jkflow! thanks! I'll be taking a look at oxidean and other DF Builds (here too!)

is there a set of guidelines for how to make a stuffing tube and how to bend it and how to make a flood tube/mount a strut?

[LibertyMKiii]

Could buy the dominator components from oxide marine and then follow his guide video https://www.youtube.com/watch?v=YAMU_ZfsqWM

For a good adjustable flooded stuffing tube setup on a mono this one from Tyler is a great example with some good pictures.
https://forums.offshoreelectrics.com...-Target-100mph

[jkflow]

Stuffing tube is very easy to do but even easier to get it wrong.
On a mono, it ends at the hull, the stinger takes over from that point. Needs to come out straight if you extend it indefinitely.
I would bend it before you cut it to length.
Do NOT kink the tube, buy some cheap tube benders in the correct size. I suggest checking OSE store for tube size utilizing a teflon tube.
Bend a little, dry-fit and bend some more until it's great, not just 'good enough', it will never be perfect.

My experience, measure, eyeball, dry-fit, sleep it over and so on. 2 days of prep for 2 min of work is about the right amount of prep.

[autolex]

Well I went ahead and ordered a driveline based on all of the collective advice i've gotten here: let me know if you see anything amiss.

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[koen]

looks good

[autolex]

Motor and mount along with ESC and mount showed up today. going to have to play around with where I think the batteries need to go to get some adjustability around the 1/3 CoG guideline.

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Need to cut off the too-small 4mm SSS factory connectors and put on some OSE 6mm connectors.

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As seen above waiting on servo and mount and driveline parts before much progress will occur.

[jkflow]

Nothing wrong with your list but a couple lessons learned, use a motor mount where you can change the motor from the top, worth the extra coin. Else, invest in a flexible screwdriver. Money wise, that equals out.
The hatch nuts/bolts will not work well, and might not want to use them at all.

[autolex]

that's good advice, i'll take it, thanks!

I have a pretty serviceable fully-adjustable TFL mount, so i can slide the rear ring completely off and then even point the front of the motor up if need be. Hoping this is enough!

[autolex]

It looks like all the parts came today but i'm going on a (real world) raft fishing expedition tomorrow through sunday in lower MO/upper AR. Should be fun!

I'll put some pictures up here next week as I start mocking things up.

Thanks for the help everyone!

[autolex]

I think that I have everything that I need now except for a servo shaft through-hull seal.

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I mocked up where all the stern hardware needs to go: I think the trip tabs need to move further away from the strut, correct? is there a guideline for setting this up? (using carpet tape here, can move easily)

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Also: I mocked up the hatch bolts I picked and I think that I can make them work with a bit of carbon plate backing that I have sitting around. I already marked up a stern doubler as well and my roll of carbon-kevlar will be here this week for my inlay.

Any guidance on having the motor forward of the esc? should I move the motor VERY far forward for any reason? (to get batteries lower, lower CoG?)

Any overall "Layout" guidance anywhere?