R-42 Twin Beast

[srislash]

I have had this on the shelf for awhile but I am really excited to get on it. I have here an AC Boats R-42 that I would love to rip up the course with the gas guys and Especially Andy.

So here is what I have:

R-42 Hull
A pair of Castle 1717's
A pair of FighterCat 300 amp 8s ESC's
UBEC
Two MBP 5mm-.250 Collets
Speedmaster Short round bottom struts(yes,,, STRUTS)
Right and left .250 cables stepped to 3/16
Assorted Speedmaster rudder parts.

[Ken_NJ]

Two projects at one time? You have the mono going with the twin drive as well!

[srislash]

I started playing with things for layout and CG. So some have put twin motors in hulls like this on the tunnel but I want to run them in the sponsons. You know, a 1717 is a healthy sized motor but when I put it in the sponson...



I am running struts and flood tubes so that I can change the prop height in the water for a change in a twin cat. I am also going to try to take advantage of the hooked right sponson which Andy designed into these hulls. The inside running sponsons last step is 1/4" deeper in the water than the outside one.

So there will be no CF inlay or anything in this one. Andy has done such a nice clean job I would hate to cover it up and it DOES NOT need the strength.

[srislash]

Two projects at one time? You have the mono going with the twin drive as well!

That thing just needs some tuning and paint now Ken. Time to start on another.

[Fluid]

I am also going to try to take advantage of the hooked right sponson which Andy designed into these hulls. The inside running sponsons last step is 1/4" deeper in the water than the outside one.

Neither of the R-42s I've owned had the right sponson deeper in the water than the left - they are both exactly the same depth from the tunnel bottoms. And both sponsons had a slight amount of hook designed into the last step. Has Andy changed the boat's design in the last two years?


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[oscarel]

I have 2 as well and they also are not deeper on the right. One of them the right sits on the middle of the pad and the left sits on the inside corner looking from the rear. I have a video posted pointing rearwards and you can see it rides light on the right side and starts bouncing side to side when it gets moving.

Twin 1717's is going to be FAST!! Are you planning on 6S per?

[srislash]

I will check it further on a table tonight guys but all the last three I have seen (one being mine) local here have been like this. I do recall asking Andy about it and he said it helped 'stick it in the corner'.

Oscaral, I am planning 6s as that is what I run my 1717 mono on but it runs good on 5s too, Probably a fairer contest against gassers.

You two are the guys I was hoping would poke in here as I know you've had a couple. Thanks

[oscarel]

I had an RC Boatworks Stryker 2 with twin 1717's on 6s and it was a blast. Good luck, I'm watching!!

[RCKong]

what cha gonna do for the hatch ?
It'll be interesting to see what a pair of 1717's will do in a large twin. Are those motors green or black ?

[srislash]

what cha gonna do for the hatch ?
It'll be interesting to see what a pair of 1717's will do in a large twin. Are those motors green or black ?

Hey Brian, how ya been? They are green cans and the hatch will start as a sheet of ply and maybe my formed styrofoam for a capsule/cockpit. I don't like the closed in one that is available.

[RandyatBBY]

I have one too. It is a blast hooks a little at high speeds I push it at 60 to 67MPH.
My start. I have a cool cowling that I am going to mold.

[RandyatBBY]

My cowl

[srislash]

That has a good look to it Randy.

[RandyatBBY]

I will post more pictures is you want me to.

[Fella1340]

Looks good, really like the strut/flooded tube in the sponson idea. I look forward to seeing the hatch design take shape

[srislash]

Looks good, really like the strut/flooded tube in the sponson idea. I look forward to seeing the hatch design take shape

I will be a little 'unconventional' on this one. That tunnel section may end up empty. I am still brainstorming.

I will post more pictures is you want me to.

Your thoughts/ideas are always welcome Randy.

[srislash]

Neither of the R-42s I've owned had the right sponson deeper in the water than the left - they are both exactly the same depth from the tunnel bottoms. And both sponsons had a slight amount of hook designed into the last step. Has Andy changed the boat's design in the last two years?


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So this is where I eat CROW. I put the hull on a sheet of glass after work and Jay and Oscar are correct. Both sponsons are even with each other and the last step is 'hooked'(for lack of a better term), just like the famed Cheetah hulls.

There is a pic either on here or in a private e-mail of one of the hulls which I stated had a deeper step and this one in particular was what came up in discussion with Andy and perhaps he thought I was talking about the 'hook'.

Anyway, my apologies for misleading the thread and Jay and Oscarel. So here are pics of the said 'hook:

[srislash]

I needed to make up a couple transom doublers. Though there is some beefy FG for the rudder mount there was nothing at the rear of the sponsons. Some 4mm CF/FG plate I had here made a nice fit:



So now they are epoxied in

[flraptor07]

This thing is gonna be a beast! And Crazy fast, can't wait to see it run!

[high-tech]

I think you gonna wanna be down in the sponsons and as close to the inside as possible

[flraptor07]

I think you gonna wanna be down in the sponsons and as close to the inside as possible

I agree, this is the way I setup my Cheetah.

[srislash]

I think you gonna wanna be down in the sponsons and as close to the inside as possible

Flood tubes guys, flood tubes are the plan. Versatility is what I am after here. But I will keep things as low as possible including the motors. Still brainstorming there. Thinking half tall mounts but with rear supports.

[Fluid]

Vertically adjustable struts can be a big advantage. Too many twins mount their stingers too low on the sponsons, ending up with either too much lift or the inability to unload big props. Saw this again today at the SAWs, the lack of vertical adjustment limits potential boat speed. Good plan Shawn!




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[srislash]

Vertically adjustable struts can be a big advantage. Too many twins mount their stingers too low on the sponsons, ending up with either too much lift or the inability to unload big props. Saw this again today at the SAWs, the lack of vertical adjustment limits potential boat speed. Good plan Shawn!




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Thanks Jay, oddly enough I think I have been doing the opposite. I was happily running 5017 props on my Shocker(my first brushless twin build) with good temps and amp draw.

I have had same with my Fantasm but recently got it aired out better and now need smaller props as now they dig in more.
These are the issues I have run into with 'fixed' stingers and here had the chance to try something different.

[oscarel]

And you'll save a little money going with struts. I also had the problem of not being able to move the stingers up. Good call.

[srislash]

I made a template so that I can take it to the drafting table to lay out the rudder/struts



And you can see I have a motor template stuck in there. I am waiting on those till the hardware is mounted to get a better fix on motor location. I am very close there as I did a previous CG layout.

So here is my blank slate:



And the question is; Whether or not to splay the struts to match up to the top deck curvature or do the whole layout 'square to the world'?

[flraptor07]

I'm thinking splayed, for this reason. It will give you another slight dimention in adjustability, being side to side. Weather it makes any difference or not, who knows?

[RCKong]

Hi Shawn,
What if you put spacers on each side of the strut in between the mount bracket ? You could get side to side adjustments on the strut also.

[jj2003]

Flood tubes guys, flood tubes are the plan.

Hi Shawn,
Please post pic's of your flood tube setup when you get there. This idea is new to me and I'm not sure how it works. I've seen Rockstar's pic's of his set up on his big mono but I believe he did a quick write up and there were no detailed pic's of how to set it up and I'm not sure I understand advantage/disadvantages of it. Thanks JJ.

[RCKong]

LOL Chris and I posted about side to side adjustment at the same time...