.12 hammerhead (project speed)

[TomMoorehouse]

ive used them on .21 and .12 riggers and they work fine. Dont worry about it Hammer.

 

[TomMoorehouse]

posting for hammer

 

[topfuel443]

Hammer, did I say 2.9lbs???....... : : ..........after the drugs wore off, what I meant to say was 3pounds 9ounces W/ fuel. I started thinking about that and it didnt seem right for a .21. I rewieghed and came up with the 3lbs9oz. on a digital postal scale. still pretty light with fuel ;D ;D

Interesting sponson design, I have a similar outer step in my tunnel. Have you used that design on a riiger before??

 

[Don Templeton]

Hammer:

This is really interesting-Great design!

What material and thickness did you use for the inner and outer

sides of the tub. Also do you use any dihedreal angle on the bottom

of the sponsons or are they at 90% to the inside.

Thanks,

Don

 

[Hammerhead]

The frame work is 3mm white birch, and the the outer decking is made of 1mm plywood. It is from Norway.

I didn't use and dihedreal on the sponsons. They are at 90degrees on the inside. The turn fin side's running surface is 4cm and the right side's running surface is 3cm. The boat is a little bit different than my other riggers, but this is a typical hammerhead sponson design. Just really small.

 

[Hammerhead]

Has anyone ever used carbon rods for linkage. I got my hands on a meter length of 2mm carbon rod. I was thinking about using it for my rudder linkage. I cut of a piece about 2" long and gave it the Hammer stress test. I ended up poking it into the tip of my ring finger on my left hand,.OUCH!!! :'(. I don't think it will have any problems with strength. Give me your ideas. Will it create interferance because of movement?

Hammer

 

[MikeP]

Hi Marty,

I know the airplane guys use them, and you wouldn't think they would cause any more interference the metal rods. The only thing I have noticed is carbon doesn't hold up well to wear. I think if it is rubbing in the same spot on a radio box seal it might wear down. Do you have any ideas for linkage?

-MikeP

 

[Hammerhead]

I will use linkage that are made of brass. They have grub nuts to hold them to the rod.

Hammer

 

[MikeP]

Brass linkage on carbon rods? If so I was wondering how they attach.

-MikeP

 

[Hammerhead]

I haven't got them in yet. Maybe tomorrow. I will send you a pic. These clevises are available for 1.5, 2.0, 2.5, rods. They don't need to be threaded or soldered. You can dye the threads into carbon rods. I have tried it before with pipe, too. I don't know if I would trust it with linkage, though. If you want to try a set, I will throw a set in with the tank.

Hammer

 

[Hammerhead]

These are some of the latest pics of my progress. I have completed the upper deck, radio and tank room covers, and I have made a 4mm thick carbon fiber turn fin spar. It has taken shape! Now I'm gettin' excited.

Hammer

 

[Hammerhead]

The sponson spar is on the right sponson. I bought some 5mm w/ 3.5mm thread Photo album binder expanders. I will cut the head of and insert them into holes drilled into the right sponson. They are 40mm long. They will make good anchors for the turnfin spare.

The next pic is of the radio box area.

 

[Hammerhead]

It's time to weigh in folks. I weighed everything. The tank, the engine all the radio and hardware stuff and the boat. Everything less the turn fin, paint, and fuel tubing. The score stands at 732 grams(2lbs 2oz). Looks like 1.7 is an unrealistic target if you want a boat that will last. I think when it is ready to run, it will be in the neighborhood of 2lbs 6-7oz. Not bad for a bullet proof boat.

Get some pics of the rear sponsons posted as soon as It stops raining. The trip from the shed to the house will leave it soaked.

Hammer

 

[Hammerhead]

This is a picture of the sponson boom set up I decided to use.

The booms are 5mm solid carbon rods. They slide into 6mm aluminum tubes. The 2 really short pipes will be used for the pushrod guides.

And the 4 medium sized tubes will be the outer pipes for the sponsons.

 

[Hammerhead]

This picture is a picture of my rear sponsons. Many people have asked me why I liked to keep them under the tub. Well, a long time ago, I had a tidewaters hydro. It was the same. I copied it with a .46 Rigger, and I liked it, so I have been doing it this way ever since. As far as technical reasons, without getting scientific about it, I believe it gives you a mixed characteristic of a 3 point and a 4 point.

Hammer

 

[MikeP]

Hammer,

Can you explain why you have the piece down the center of the rear sponsons? I like your carbon rods and aluminum tubes. Your whole boat is looking nice.

I like the rear sponsons under the hull to. Less drag like a 3 point, handles like a 4 point.

-MikeP

 

[Don Templeton]

Hey Hammer:

What size flex flexshaft are you planning? Are you going to use teflon?

"Great" Thread!

Don

 

[_laxmasta2039]

hammer,

lookin' great!!

jeez, i started my .18 rigger 'bout a month ago, and i'm only about halfway through making the hull/sponsons, havent even started on the booms or back sponsons, and your almost ready to load that sucker up with a .21......i like the back sponsons......IMO, riggers look better when they appear to only have sponsons in the front [back sponsons under the hull]. Tom's firefighter plans have the rear sponsons exposed though, and i'd really like to stick to the exact plans before i go off on my onw, especially since it's my first 'rigger. it seems like having the back sponsons so close might make a big change in the stability or prop walk or both.......your .02 Yen please? ;D ;D

joe

 

[Don Templeton]

Hammer:

In your latest hull pictures, it looks like you have an extra layer

of wood in the rear part of the engine compartment. Is this to stiffen the bottom or am I seeing things? What is the thickness of your

bottom?

Don

 

[Hammerhead]

Hey Don! That piece of reinforcement that you see is part of the stuffing box. That is where the pipe will go through the bottom of

the hull. I will use a 4mm flex cable without a ferrule. The prop shaft is welded onto the cable.

Lax! my 20yen on the rear sponsons. The reason I make them this way is, I have been making them like this for years and I'm used to this method. As far as Tom's fire fighter, He put a lot of thought into the design of his boat, so I think his set up will prove to be the better way for you to go. When I build Tom's FF.12. I will go by the book.

Hammer

This is a picture of my tank and propellor. This is a V937. I had to make a collar for the prop, because it is an American size. Octura hasn't made any of the V series in millimeters yet. You can see the brass collar sticking out the back of the prop. It will slide in to where it wont be visible.