First build .... Hydro

[stubbs]

I surfed the site quite a bit and figured out almost everything I need to know to get myself in trouble , I mean started We're not out for comp just bragging rights so perfection is out the window

Just a couple simple starter questions and the build will begin.

1st..Where to mount the motor ? Midway or more twards the front ? This is what my first guess is , lol. More forward , back ? Am I looking for a balance point ?




This is where I'm thinking the hardware should be ..... Not sure if I need the stabilizer thing on the left or not. It's all just stuck on with servo tape , once I mount them they will be straight .... somewhat maybe.




After I get it all mounted up I desided I'm gonna do some body work. It's been awhile since the high school rot boxes & gallons of bondo but I think I'm up for this one.

[Dr. Jet]

Turn fin goes behind the right sponson, not on the transom. The Graupner fin you have may be a bit "light" for that hull. You want it to balance about 1" to 1-1/2" behind the sponson.

[Ub Hauled]

The Doc knows what he's talking about...
that particular boat (red one) is owned
by a mutual friend now and I clocked it at 56mph!
Use metal turn fin and the rudder setoff to the right,
it'll give you better cornering.
The placement of the motor boils down to how you want the batteries to
sit in there. I find it easier to move the motor aft a little bit and place the
batteries a bit deeper under the "hood". It makes plugging and unplugging the
motor cables much easier... if you tuck it under too far, you'd have to remove the
motor every time you needed to unplug. CG is about 1" behind for me... given your prop does NOT have too much lift it should be a good starting point like Doc said.
Another thing, make sure your turning fin is SHARP! As well as the rudder and the trailing edges on the sponsons it makes a good difference.

[Dr. Jet]

Stubbs,

I used that same motor mount in the red boat in the photos, but I found it did not place the motor in the optimum angle, plus it was a bit "wimpy". Fast hydros take a bit of pounding and with a long motor cantelevered off the faceplate of the mount, it can flex quite a bit. I sanded my mount to a better angle and epoxied carbon fiber sheet onto it to stiffen it up. Were I to do it again, I would add a support under the forward end of the motor and use a zip-tie to hold it down. You don't want any flex in the motor installation. A rigid motor is a happy motor.

[stubbs]

Funny you mention that , I have done the same thing onone of my ground RC's with the XL can in it. That's a long motor to have just one end supported. I didn't think it would thrash around as much in a boat so never gave it a thought.

I have a list of items that are in my cart for off shore electrics , some extra stuff and some to fill the gaps that were forgotten about with the first order (not from here)

Should I just get another mount that will work out better ? I'll still support the front of the motor in any event. Should that be a straight run from the motor shaft to the prop or will I end up with a bit of a bend in the tube ?

Also I was going to get this turn fin to replace the plastic one that was in my kit , good choice ? I'm into this thing so I may as well do it right the first time instead of making swiss cheese out of it messing with different stuff as I go.

http://www.offshoreelectrics.com/pro...od=dh-aqub9516

The hacking is going to start tonight better check the cooler first though . I want to get all the hardware mounted up & the holes drilled so I can start on the body work. It may get put off now if I should upgrade on the mount.

BTW , thanks a million for the pic's of your hydro & advice. I wanted to ask if anyone had some pic's but figured Id'e surf first being the new guy. I hate getting yelled at to use the "search".

[Dr. Jet]

The way my H&M Viper worked out, I had a very gentle bend in the drive. Look at the photos. It would have been simple to replace it at any time with a wire drive. I used the Fuller’s turn fin on the Viper, but my most recent hydro of the same size (Campbell Classic) used the HSX turn fin from Korea (http://www.toughracing.com/). I’m quite pleased with this fin. Very stout! Sharpening required.

As for the motor mount, you can adjust it to suit your needs as long as you do something to support both ends of the motor. Steve sells a nice mount on this site that is fully adjustable. Take a look at that one as well.

[stubbs]

Normal night going on , about 6:30 I pack up my 2 1/2 year old and hit the local Walmart for some sand paper , filler & goldfish (for him). 8pm comes and I put him down for the night and head for the workshop. I'm grinding away at the seams with the Dremil , hitting them with sandpaper , back to the Dremil the whole time thinking this really isn't so bad. A few times thinking it's more relaxing than than the messy nitro ground RC's. I get done what I need to and clean it off so I can put the filler in the rough spots and let it sit overnight then hit it some more tomorrow. So now the hull is covered with dust so I fire up the compressor to blow it off and find a few cracks (now that the dust got in them)

I can feel underneith that it's splintered, there's also another one behind my thumb about 1/2 the lenght but that one's not splintered underneith. I had to push down a bit for it so show in the pic. Not pushing down you can just about see it.


This one is heading 45 degrees away from the corner , you can see it but you really have to look , the oppisite corner has the same thing also.


LMAO , any ideas on this one I was thinking slap a decal over it and call it a day ............ sealed & hidden :)

[Dr. Jet]

Two years from now, these cracks will be insigificant. FG boats take a lot of abuse. You will find a lot of stress cracks in the gelcoat of any well-used hull. Either spend the time to make it pretty, or just call it good enough. The choice is yours.

You could add epoxy-soaked CF cloth to the underside of the blemshed areas and sand/fill the cracks, but why? It does not look like a structural blemish, just cosmetic. Build you first hull to run, the next can be for looks after you have sorted-out the important running details

Hammer down and turn right.

[stubbs]

All the hardware holes are drilled , mounts in place & bodywork is done. I'm just waiting on a prop & bullet connectors now. I put down the first coat of paint tonight. I'm going two tone so I had to back the boat in white first but the main color will be the color of the hatch. It'll be a few day's before the paint is done then I want to give it a clear coat so I guess it won't be going for the weekend.

When I get the paint finished I'll post some more before & after the decals.

[stubbs]

Todays work ......... Is it better to host the pic's myself or use the attachment so they are thumbnails at the bottom or don't it really matter ?

[banzilla]

Looks pretty dam good. Cant wait to see it go.
Sunday? or am I relegated to goin to a B-Day party?

[stubbs]

Did the maiden voyage over the weekend and it didn't sink

It's cavatating (sp?) awfull. It's taking me forever feathering the throttle to get it to catch and take off. If I drop down to about 1/4 or less of it's top speed it start's all over again. I messed alot with the pitch & angle of the prop and batt placement and saw big differences on top speed & how it would plane out but nothing helped taking off. I'm using an Octura x640 sharpened and balanced as of now. Will a prop with 3 fins @ the same size help me out at all or stay with the 2 fin and go bigger ?

Is trying out different stock props till I find the right one worth it then get it sharpened & balanced at that point ? I hate to keep throwing darts at 35 bucks a toss till I find the right size.


........... TY

[kck741]

What type of batteries are you running

[Rex R]

it has been said that; hydros are not for the timid(since you pretty much need to do a full power start to avoid having a submarine ). sounds like you need a bigger prop...like maybe one of the graupner carbon props(k-series). for testing purposes they work nice, methinks a 'k-42' or a 'k-45' should launch your boat.

[stubbs]

What type of batteries are you running

2-2S LiPO's in series for a 4S total on a 9XL motor.

it has been said that; hydros are not for the timid(since you pretty much need to do a full power start to avoid having a submarine ). sounds like you need a bigger prop...like maybe one of the graupner carbon props(k-series). for testing purposes they work nice, methinks a 'k-42' or a 'k-45' should launch your boat.

I did notice that , the water just rolled up and over the front for a good 50-60+ feet till I was able to get it going.Seemed kinda slow to me but maybe not. There are only 3 of us running boats around here and between all of us we make a whole if we're lucky. Not to much hands on advice around these parts, lol. My buddy has a stock brushless SuperVee 26 on LiPO and we were pertty much dead even with speed. Not sure if they can compair or not but it's all we got