Skunkworks Mach5 30" Cat Build [Archive] - Offshore Electrics Forums

FE_Chris

12-29-2007, 09:49 PM

Hey guys. I am building this Skunkworks cat to race in the SSLSO class with our club this year. I have not gotten very far. I installed the hardware tonight so I really am just getting started. I got my order from Steven today so I almost have everything I need

I do have a question. The two pics of the strut (1st pic and last pic) I took are differant, if you look I have the strut moved UP all the way in one pic, and moved all the way DOWN in the other. I wanted to know if you people thaught that I had enough ajustment in there. It's mounted up now so I hope so!

Also, anyone know the CG in the boat?

I need to get a tube bender....then I can get this build moving along....

This is gonna be the setup

SW's 30" Cat Hull
Mach 5 Inline hardware .150 cable
ProBoat BJ26 Brushless Motor
Hydra 120 ESC
4s1p PQ lipo

Im hoping for 40 MPH and WOT turning. :-)

obrien

12-29-2007, 10:33 PM

Sorry this is a bit off topic, but what does LSO mean?

domwilson

12-29-2007, 10:43 PM

I have one. It has a Feigao 9XL, Hex 120 and aeromarine hardware and a x637 prop. Here are some pics. It's faster than my SV27 with a X642 on lipos.

FE_Chris

12-29-2007, 10:47 PM

Limited Spec offshore. We call is SS or Super Sport cause instead of brushed 700's we are using SV27/PB brushless motors.

Thanks for the pics....Damn your strut looks high! I guess the good thing is, if I set mine a little to low, I can always trim a little off to move it upward.

How do you like the handling of the SW's Cat?

obrien

12-29-2007, 11:34 PM

what hulls are allowed in that class?

domwilson

12-29-2007, 11:49 PM

It turns real good like its on rails. Planes really nicely. I like it. The strut is up high because these have a tendency to porpoise. I'm going to install a 8XL, hydra 120 and a X640 in the next week. Probably won't get to run it or my other boats for the next few weeks, but it is definitely my favorite boat.

Fluid

12-30-2007, 01:20 AM

I need to get a tube bender....then I can get this build moving along....

What do you need a tubing bender for? Certainly not for the stuffing tube! :laugh: You can bend K&S brass tubing very well with your hands, just go slow and have the piece longer than you need, cut it to length later. I just got finished bending a new stuffing tube for my 10S catamaran - its 5/16" diameter brass and if I can bend that by hand (it was easy!), then you can bend smaller tubing just fine. I can bend 1/8" tubing into a 3" diameter circle by hand with no crimping or collapse. :thumbup1:

DO NOT ANNEAL THE K&S TUBING! I do not know where this old wives' tale came from but it is BS. It bends just fine as it comes off the rack. If you do anneal it - it will be too soft and the cable or wire will not be well supported. And don't bother filling the tubing with sand or sugar or anything - it bends fine without collapsing. Just go slow and make gradual bends.

.

domwilson

12-30-2007, 02:05 AM

Fluid is right. You should be able to bend K&S by hand as long as the bends aren't too great. If you are worried about it collapsing, put the telflon and the flex in it before attempting to bend.

Diegoboy

12-30-2007, 08:08 AM

Fluid is right. You should be able to bend K&S by hand as long as the bends aren't too great. If you are worried about it collapsing, put the telflon and the flex in it before attempting to bend.

Fluid is always right, but inserting the liner and shaft will prevent collapse, but don't think it'll guarantee a usable tube. I tried that, it didn't collapse, but the kink was enough that pulling the cable out was tight! Needless to say, I couldn't use that tube and had to try again.

SJFE

12-30-2007, 09:03 AM

I have a bender & Iv'e ruined 2 feet of tubing so far. When I get more this afternoon ima do it by hand.

FE_Chris

12-30-2007, 10:44 AM

Thanks guys you are right about the tube being easy to bend! Cause I think I am ready to glue and glass this bad boy in I want you to check the pics, I think it looks good but I wanna make sure.

I have the teflon tube running into the strut. The brass tube is right up next to it, I am going to move it away 1 mm and shrink wrap it up.

Also, as far as epoxying the stuffing tube in......I was thinking I would use some small pieces of fibre glass cloth AND epoxy. Thats a big hole to fill it looks like epoxy will just run right out!

Im gonna wait for some replys before I procede.

Also, I was gonna glue the tube....THEN glue the motor mount with motor and flex cable/collet installed that way EVERYTHING is lined up all nice and perfect. Well, actually, I would like to set the mount like this with some epoxy, then remove the motor so I have room to work and start glassing it on real good with the cloth and whatnot.

How's that sound?

FE_Chris

12-30-2007, 10:49 AM

Thanks dom. I guess i'll start with the strut all the way up when I go to test and lower it as I see fit. Looks like you have your batterys quite far back in the boat too.....COG needs them that far back?

Looks good man!

It turns real good like its on rails. Planes really nicely. I like it. The strut is up high because these have a tendency to porpoise. I'm going to install a 8XL, hydra 120 and a X640 in the next week. Probably won't get to run it or my other boats for the next few weeks, but it is definitely my favorite boat.

domwilson

12-30-2007, 10:54 AM

I had them further forward and it ran too low in the water. With Lipos, it seemed to run better there. Chris at Fine Design recommended thats where I should start. He was right. As far as the stuffing tube. Maybe some electrical tape on the underside might work to prevent the epoxy from "bleeding" thru. Maybe someone has a better idea?

Fluid

12-30-2007, 11:23 AM

I have the teflon tube running into the strut. The brass tube is right up next to it, I am going to move it away 1 mm and shrink wrap it up. I don't use the teflon, haven't for about ten years. But it is fine to do so, just remember you still have to use a good lube.

Also, as far as epoxying the stuffing tube in......I was thinking I would use some small pieces of fibre glass cloth AND epoxy. Thats a big hole to fill it looks like epoxy will just run right out!
I always put pieces of tape on the underside of the hull to keep the epoxy from running out. A few pieces of cloth are a good idea too, or use something like MarineTex or JB Weld.

Also, I was gonna glue the tube....THEN glue the motor mount with motor and flex cable/collet installed that way EVERYTHING is lined up all nice and perfect.
I usually mount the motor first, then move the stuffing tube around so that there is a perfect alignment between the drive cable and the motor....but I have done it both ways. Use whichever you feel most comfortable with, but just make sure the alignment is perfect. Sometimes I take an hour or more moving the motor or tube around, cutting the hole bigger if needed, until everything is just right. It makes a difference in the final performance of the boat and the life of the driveline.

Fluid is always right...
Not hardly - but I have made enough mistakes and seen enough mistakes over the years to know what usually does not work best. :blushing: If the K&S tubing kinks, then you are trying to bend it too sharply. Use both hands and your thumbs to make the bends. I have bent enough tubung over the years - many many dozens - to know that the method works well without anything inside the tube when you bend it. :smile:

.

FE_Chris

12-30-2007, 12:38 PM

Thanks fluid! I went ahead and grew a set, and epoxyed this bad boy in. I used a few pieces of cloth as shown on top, and I did so on the bottom too, just not as much. The epoxy is quite thick, and although it does run through the hole it's not a huge issue now with the cloth.

I have everything lined up pretty good. I am more comfortable doing things this way for sure.

Thanks guys. More to come....Im gonna have to finish the epoxy on the bottom later, than after that dries I am gonna do the mount. seeya!

FE_Chris

12-30-2007, 01:26 PM

Top is done. Bottom is now done. Stuffing tube is complete. I am going to get some food, and when I come back and after I eat, the motor mount is gonna get set...........

Rex R

12-30-2007, 01:53 PM

a few comments...1) last few holes I've plugged(stuffing and others), I use vynel electricians tape to keep the epoxy from running through. 2)looks like the glass on the inside either has air under it, or didn't 'wet' thouroughly(only a comment I'm reasonable sure that your technique will improve with practice, hint thinner epoxy works better when fiberglassing). 3)jolly good! :), there that wasn't so hard was it?(nerve wracking maybe :))

FE_Chris

12-30-2007, 06:20 PM

Thanks rex, I actually took the pic before it was dry, it has disapeared into the glass more now, looks better. But yeah maybe I did let soime air under it :smile:

I just finished installing the motor mount. I covered the balsa wood (could'nt find bass) with epoxy, and I used some strips of cloth on the bottom. I cut the stuffing tube a bit short...kinda on purpose...kinda not. I wanted it short....But not this short! O well, It works and it is about as low as it can be without making some real big bends in the tube....right now the cable spins nice and free...it's not hardly bound at all by the slight bends in the tube.

Think it'll hold? Let's all please try to remember this is the first actual boat I have built on my own :D the 1st!

and uh.....welll I guess it's not so low but it's the only mount I had here that would work!

txboatpilot

12-30-2007, 07:19 PM

Boat is looking good!! Where did you find that hardware ??

Rex R

12-30-2007, 07:30 PM

1st boat or 9th I still agonize over where and how to drill that hole for the stuffing tube till I finially grab the drill and just do it :). off hand I'd say it looks like it should hold...I'd keep an eye on it though(as part of an after run check, deffinatly after a colisition). at least your motor is comparatively low mass, which should keep the stresses down. low? I've had to notch the decking under the motor to get it low enough :). time for you to drill the rudder mount holes and prep the hull for paint.

FE_Chris

12-30-2007, 07:40 PM

Thanks Rex. But actually it is a inline system. The rudder is already installed. As far as the Motor mount....O yeah, she's gonna hold! Now that the glass is dry, man it is in there! Gonna take one hell of a crash to tear that mount out..... The wood covered well with the glass too....So hopefully no chance it's gonna rot or anything like that.

TX.....The hardware is from Mach5 Racing. Ken Joye is the owner, he is in my our club MMEU also. He can be reached through RRR.com

Next I need to install a servo mount, linkage, boot, on/off switch, water outlet, inlet bulkhead, I still need a few things......

Rex R

12-30-2007, 08:04 PM

was thinking fatigue would be a factor... I do reccomend a 'simple' easy to touch up paint scheme for race boats(hi-vis is good :)). thinking that my Mean machine will be day-glo pink for the underside w/ a day-glo green upper(I want no confusion about whether it's a buoy or spray(yellow, white))

domwilson

12-30-2007, 08:19 PM

Looking good. What prop are you planning on using?

domwilson

12-30-2007, 08:22 PM

Here is a pic of a high speed turn. This would tumbleweed an SV27.

FE_Chris

12-30-2007, 09:29 PM

Ditto. Thanks! Thats what I wanted to see!

Here is a pic of a high speed turn. This would tumbleweed an SV27.

domwilson

12-31-2007, 12:37 AM

Here is a video of Scott's first outting with this hull.

http://www.rcflix.com/photopost/data...k_Works_30.wmv

Diegoboy

12-31-2007, 01:02 AM

It's a broken link...

Diegoboy

12-31-2007, 01:05 AM

Is this (http://www.rcflix.com/photopost/showphoto.php?photo=2604&cat=all&si=skunk) the link you intended to post?

domwilson

12-31-2007, 01:06 AM

Try this one.

http://www.rcflix.com/photopost/data/500/Skunk_Works_30.wmv

domwilson

12-31-2007, 01:07 AM

You got me...I was slackin'...

Diegoboy

12-31-2007, 01:09 AM

It's cool. Just tryin' to help.

domwilson

12-31-2007, 01:24 AM

Hey Diego,

Have you tried one of these? What would you recommend? I'm trying to make mine faster. I followed your Miss Bud conversion and I liked what you did there. I converted mine and I'm happy with it.

Diegoboy

12-31-2007, 01:26 AM

The Skunk Works hull?

domwilson

12-31-2007, 01:28 AM

Yes sir. That's the one.

Diegoboy

12-31-2007, 01:34 AM

I would have gotten one of the Skunk works, but I didn't. :unsure:
I do miss my Miss Bud though. I wonder what Chonburi is doing/has done with her?
You converted a pro boat hydro hull too? Cool!
As for this cat? I'm kind-of new to cats. I still have yet to run my BJ with the ammo in her. Finally got the parts I needed, now it's the weather holding me back! :cursing:

domwilson

12-31-2007, 01:39 AM

I have a Blackjack26 too. I'm going to get rid of that steerable outdrive before I put it in the water. Got the ammo and the hardware. It's just a matter of getting the time. That and I like my Skunkworks Cat. It runs great. Would like to go faster tho'. I run just for fun. Not into racing yet.

Diegoboy

12-31-2007, 01:48 AM

Here's some good reading, if you havent already found this... (http://findarticles.com/p/articles/mi_qa3918/is_200502/ai_n9477872)
Someone took the time to do that to my H&M M1 supercat S

domwilson

12-31-2007, 02:01 AM

Did it help? I would think on a relatively small surface area and contact patch, that this would not be an issue.

Diegoboy

12-31-2007, 12:47 PM

M1 Supercat S has just arrived a few days ago. She's still waiting in line for build time...

http://www.diegoboy.com/misc/100_2043-sm.jpg (http://www.diegoboy.com/misc/100_2043.jpg)

FE_Chris

12-31-2007, 04:24 PM

Hey Dom, you run 4s1p and a 9xl right? I think that was it...man your SW's cat should fly dude! I mean 40's anyway I would think....maybe 50...Maybe?

Ohh and I also drilled the two holes and installed Aeromarine water inlet and outlet fittings. Smoooooth lookin for sure! Nice and clean! I'd take pics, but there just fittings so, you know.....

domwilson

12-31-2007, 05:56 PM

Yep. It moves pretty good with a X637. I'm going to try an 8XL with a X640 prop soon... Ok when I get a chance.

Fluid

12-31-2007, 07:58 PM

Did it help? I would think on a relatively small surface area and contact patch, that this would not be an issue.Actually, blueprinting the sponson bottoms can make a significant difference on some boats. A flat smooth surface is the first thing to try to get, with a 400-600 grit finish - NOT shiny poished. Sharp trailing edges are the most important, and flat surfaces are critical too. On one of my SAW cats, blueprinting the bottoms added over 4 mph, and that was with a pretty good molded bottom to begin with. :smile:

,

domwilson

01-05-2008, 01:31 AM

Hey FE_Chris,

How's the build coming along? Anxious to see how yours performs.

FE_Chris

01-05-2008, 08:15 AM

Well, I have'nt got much else done sence I last took pics. I've been SUPER busy plowing snow, and salting...heck, I put in a 26 hour day/shift the other night!!!! Not complaining just saying :-)

I need a servo mount, linkage, linkage boot, and a few other misc things. Maybe i'll get some building done tonight if the LHS has what I need.

FE_Chris

01-06-2008, 09:09 PM

got some forward progress made.... servo mount installed and glassed, antenna mount, linkage boot, water inlet and outlet, blocks for ESC and RX to sit on.....

I still need to bend the linkages, install them, install rx, servo, ajust strut for 1st run.....

Good thing the ponds are froze for the next few months :cursing:

domwilson

01-06-2008, 09:40 PM

Looking good! What powerplant and prop are you going to run?

txboatpilot

01-06-2008, 10:14 PM

Looks great!! What esc and batteries are you going with??

FE_Chris

01-06-2008, 11:28 PM

prop is gonna start with a worked over x442.

ESC is a hacker 77 I have laying around. Or a hydra 120.

All my batteries are Polyquest 25-30c, I have a set of 10000Mah 2s1p Tanic packs 10c, and I have a set of Dualsky 5000Mah 2s1p 22c cells.

Kinda a mix of lipos. I run mostly PQ, but I like to try others when the price is right. The tanic packs work great! nice cells for sure! I have not tested the dualsky packs...they should be pretty good I hope!

domwilson

01-07-2008, 12:24 AM

Is that a bj26 motor?

FE_Chris

01-07-2008, 08:34 AM

Dom, Yes. I find out on sunday at our club meeting wether or not they are going to be deemed legal like the SV27 motor is. The SV27 motor really is the stock motor of choice for clubs, but ours wants people with a BL BJ26 to be able to come and run also! But I dunno, cause the motors are NOT the same. IMO the BJ motor has a little more oomph then the SV27 motor, runs cooler IMO too.....