Sprint Cat40 twin

[drwayne]

I will post pictures, and add details as time permits.
Im a busy bloke !

Bought mid June from Australian importer.
Had slight transit damage to tip one sponson which I knew of before buy, but the sh ite gel on cowl was a disappointment.

Intent is as follows
twin 1518/1800 swapshop OSE
HRC 1518(rib) coolers OSE store
6S2P shared, or 6S1P to each single.. finished with 6S1P to each
200+A per side finished with 2 x SF240HV swapshop OSE
stingers 2x1/4 modded to 3/16 full rollers with oil feeds eBay and local bearing supply
ext LVC dimension engineering from OSE
ext UBEC Turnigy 3S10-15A HC at HK
L&R hughey 3/16 flex OSE store

Fresh from box
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Engine mounts 75x50x4mm 90' drilled to suit.
a basic shape first up
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And then the shape for sponson insets
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And next, the sh it gel finish on cowl
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at top centre this pic is the gel issue.
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[drwayne]

I scoured for these, and found a pair 1/4 stingers where center was able to take 3/16x11/32 roller bearings.
I drilled out 1/4ID teflon bushes and stinger to 11/32, and then fit the rollers. ( get in ya bastard ! )
secured with 603
27062011329.jpg

Laid CF through tunnel, and engine mounts
( more cf when h/ware established )
18062011317.jpg

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Mock up of stinger and rudder locations
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Stingers are oil fed..
Manuf says the rollers prefer oil >25k rpm

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[drwayne]

'God' pokes his head in ....


Engines + coolers attached .
5/32 water lines ( brass ) L+R from rear to engines epoxied under deck lip
SF240HV Escs are approx location

[Steven Vaccaro]

Had slight transit damage to tip one sponson which I knew of before buy, but the sh ite gel on cowl was a disappointment.

He builds some boats capable of very fast speed and good handling, but the gel isnt always the best.

[JCAustralia]

Love the oiler

[mm123521]

drwayne:
I just ran my twin Sprint Cat an hour ago, it did 70.6 MPH (113 KM) .
I am running CC 1520 motors (1600 KV) on 6S.
6S1P on each side -- this thing requires 40C batteries -- lesser batteries result in lower speeds and hot batteries.
447 Right and left props.


With your 1800Kv motors, your going to be running more RPM than me -- buy good batteries!
I am running GenAce 5300 MAH 6S -

Mark

[millzee]

looking very nice, love the strut set up

[Rumdog]

You are going to LOVE this boat. I'd mount the stingers a tad higher than your mock up position though.

[Rumdog]

Also, I am anxious to see how it handles with the long rudder bracket. I used a very short bracket and it worked great.

[drwayne]

drwayne:
I just ran my twin Sprint Cat an hour ago, it did 70.6 MPH (113 KM) .
I am running CC 1520 motors (1600 KV) on 6S.
6S1P on each side -- this thing requires 40C batteries -- lesser batteries result in lower speeds and hot batteries.
447 Right and left props.


With your 1800Kv motors, your going to be running more RPM than me -- buy good batteries!
I am running GenAce 5300 MAH 6S -

Mark

Hiya
I have 6S45c5000 nominal

OSE speed calc suggests.
yours 6S 1600 x447 = 87.09mph (single)
mine 6S 1800 x442 = 87.47mph (single)
or as 6S 1800 x447 = 97.88mph (single)
here's hoping the twin setup makes it that fast .
go figure !

Jay (fluid) .. any numerics on twin Vs single re fecalc speeds ?

thx

Wayne

[mm123521]

Wayne,

442 were too small to hook up -- they cavitated for the first 20 feet or so.
All those speeds dont account for slip.
447's and 6S and 1600KV = 87MPH x 20% slip = 69 MPH
I am doing just a little less slip (19%) when I get 70.6 MPH.

With your 1800KV you should get about 77 or 78 MPH, but youll have trouble keeping it from blowing over at that speed.

My setup will cook low C batteries.
Wires are quite warm after a run.
ESC's are quite warm, but not hot.

Acceleration is incredable!!!!

Mark

Mark

[drwayne]

Mark.

end of day, it would be best on water to calculate speed/losses.

However IME the slip loss of a single FECalc setup is canceled in a twin.
FECalc is a great estimator,. with a wide gap for dockside debate !.

see Maritimo link in sig re FECalc estimate
2 x 1512/1800, x442LR, 1x6S45C5000 =

W

[carlcisneros]

hey drwayne,
here is some footage of rumdogs twin aeromarines sprintcat running.

will get an idea of how it should run once set up properly.

http://www.youtube.com/watch?v=wW5O3sMSBkE

[drwayne]

I think the USPS truck was hijacked by Martians ... still waiting after 3+ weeks for my last bag of bits to arrive .. holes in deck need filing !

roller stingers insitu
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steer servo and stinger oil feeder
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same again ..
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Holes for external safety loop .. disconnects battery from esc ... for 'justin case ' .. mandatory in Au rules book.
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[drwayne]

Oh my goodness ( profanity kept in check )
Big pussies are definitely more fun.
Took her down to the bird sanctuary late this arvo,, sun settling down for the niight.. the doof doof doof noise from the adjacent micro concert ( 600 ppl ? ) drowned out by her ecstatic scream of enthusiasm as I applied the GO finger.
A field of curious onlookers teleported in .. there will be 70+ new junior members at our local club, if they can convince their father the benefits of a battery powered pussy....
Id be there still, but the pond monster swallowed a prop.. the daft bullet nuts just dont do the same as nyloks ...