Hammerhead .21 Build

[moparbarn]

Good to know, Walt and Larry. I haven't figured out the exact size of tank I will need, but when I do, I will get my order in.

I'm with Tim for now. I want to use the original sleeve if possibe. If it doesn't work out, I will get the RC car P&S.

I bought some West Systems 105 epoxy resin, and 205 fast hardener. What kind of hardener do most people use to seal the wood?

Will the 205 be fine? In the past, I have used poly-urethane sanding sealer, but I can't get it in the US.

i've been using DEFT brand lacquer based sanding sealer, with great results. get it at lowes .

 

[Hammerhead]

I have to go to Lowes today, anyway. I will check it out. Thanks for the tip mopar!

 

[Hammerhead]

I drilled and tapped the holes in the turn fin spar. I will have an inch each way to adjust the turnfin position. I also piped a 1/4 inch piece of graphite tubing in to the end of the spar to put a bolt through to hold the collar and rod that stabalizes the turn fin. I also reinforced the transom with carbon kevlar.

I still need the strut before I can skin the bottom of the hull. Jim Mamiril is making me the ultimate strut assembly for me as I type. Can you say ROCKET?

 

[Michael Costanzo]

looks really,really nice. good luck with it. mikie.

 

[Hammerhead]

I made a saw horse type stand for my .12 rigger. It works okay, but I thought that with my .21 I would try to make one that was a little more the norm.

I had some burly Big Leaf Maple boards that I harvested from my property a few years ago. They were just sitting in the garage, so I milled them down with my table saw. I got all the pieces cut out and rough sanded. It will look really cool when I get the clear coat on it.

 

[Hammerhead]

I usually do most of my boat building at my shop. Being that it is the Christmas holiday, I'm stuck playing around with stuff that I have in my garage. As I mentioned earlier in this thread, I would be making a 24V pit box. I started on that and I got my boat stand all put together. This burly maple is sure nice. The finer the grit the more the character comes out. And to think that my better half wanted me to make a jewelry box out of it. Now that would have been a waste Hopefully I will get some more done on my rigger this week.

 

[Hammerhead]

After all the flack I got last season in district 8 for not having a 24V pit, I'm almost there. It will have 2 12V 7amp batteries, a toggle to switch polarity, a toggle to break the series so I can charge, and a toggle to select individual batteries to charge. I think it will work nice. Now I guess, all I need to do is get a Mike Hughes turn fin for my rigger. Then I'll be set.

 

[Hammerhead]

I got all the switches in. I put in banana plug recepticles for the starter and brass posts for charging the batteries.

 

[Jim Mamaril]

I got all the switches in. I put in banana plug recepticles for the starter and brass posts for charging the batteries.

Very nice Marty, Look for a package in the mail any day now.

 

[Hammerhead]

I can't wait :lol: Also Jim., If you can email me the numbers to you 1452, that would be cool.

 

[Hammerhead]

In the last week or so, I have received a lot of hardware for this project. I have been able to make quite a bit of progress.

I skinned the bottom, and installed all the control rod tubes in the radio compartment. Tomorrow I will install the engine mounts,engine and strut. Hopefully, I will be able to put in the stuffing tube. After that comes the rear ski.

 

[RodneyPierce]

Looks great!!!

 

[Hammerhead]

I didn't quite finish putting in the stuffing tube, but It's close. I found one problem; my 18" 3/16 Zippkits flex shaft is an inch too short. I wonder if someone out there makes a flex shaft longer than 18" in 3/16" that has the prop shaft already attached. I could probably do it okay myself, but I would prefer it done right. Any advice on where to look would be appreciated. I'm using one of Jim Mamaril's struts. He sure makes nice struts.

 

[MattHench]

Marty, contact Timothy Jones on here, he has Hughey shafts in 24" lengths. Lookin at your pic with the engine installed, it may be the pic but is there enough room for your header? Lookin good, Matt

 

[RodneyPierce]

Hammer, I have a question for you. I assume this boat is going to have a ski, correct? Do you think your motor placement might be too far forward? Seems the ski boats need alot more tail weight then a standard shoe'd rigger.

 

[Jim Mamaril]

Marty, I think Rodney has a good point your motor may be too far forward.

 

[Hammerhead]

I don't think the pictures depict the engine position well. The engine is only 2" foward of the tub center. In my .12 it is 1.5" foward of tub center. As far as the relation to the sponsons contact with the water, the distance is 1.35 times larger than my .12. This boat in general is scaled 1.35 times my .12. Of couse, I made some changes, for example the tub height is lower than scale and my ski will be deeper than scale. I made this decision based on the posture of my .12 when it was running. In my opinion, the ski on my .12 should have been slightly deeper.

 

[RodneyPierce]

I think there is a rule like "70%" tail weight on a ski boat. But dont hold me to that number. As I dont remember exactly.

 

[Hammerhead]

Rodney, What degree of AOA do typical riggers run the ski at? I run mine at a half degree less than the sponsons. Just my personal rule of thumb when I build. Seems to work well with my designs. This might have a lot to do with the tail weight calculations.

 

[Hammerhead]

This is what the ski looks like. I haven't glued it down yet. I will when I seal the inside.