Riggers from Japan

[Propjockey]

One word of warning--carbon fiber is electrically conductive where fiberglass is not. If you use a Dremel (or any motorized tool) to cut carbon fiber, don't let the dust/fibers get sucked into the end of the tool. It will short out the motor.

Guess how I found out.............. :-[

 

[MikeP]

Tom,

The .21 is awesome, I practice with a guy who has a SGMAC. We are pretty even, I have a bit more speed in the straights. I still have 2 props that I didn't get to try, I am using a 1445 pitched 3.1 and have 3.2 and 3.4 still to test. I know I can get more speed, It's fast enough for heat racing now, I will find out this spring when I go up against Al Hobbs, Erick McNeil and others.

I use a dremel with a flexable shaft attachment , the flex shaft is much better to work with. I cut all the CF using a cutoff wheel.

I got the tape from Hammer with the 2002 JMPBA nationals. I will have the converson done today and get it to you.

-MikeP

 

[TomMoorehouse]

sounds good mike!

cant wait for the videos!

 

[Hammerhead]

Hey Tom! I ordered an O.S. .12TZ today. I want to put it in an FF. Can you help me out? If you have a prototype laying around or get me started scratch building it.

Hammer

 

[_laxmasta2039]

hammer,

my redneck buddy [matt aka bubba] is pretty close to being done w/ his, im sure he could give you pics or something if Tom doesnt have any around......

tom,

i've got a quastion about that same lil' rigger- using the

program you recommended, the plans came out with the boat being 25" or 26" long [cant remember which], and a pretty solid 25-26 since he beefed up the transom, sponsons, and some other stuff- now matt's hungry to try a .21 in the thing. with a long strut bracket [to set the prop off alot] and one of hammer's mild OS engines, do you think the boat could run on a .21 without being impossible to drive?

joe

 

[TomMoorehouse]

well.... i guess it could work...... but it might get hairy at speed and want to blow off.

 

[Ian Inverarity]

Hey Hammer,

I recently weighed my 90 rigger and it was 3.6kg dry. What was the weight of your carbon Hammerhead 90's? I'm trying to get an idea if that weight is okay.

Ian.

 

[Hammerhead]

Hey Ian! With no fuel, my CF Hammerhead weighed about 4.5 kg

It was 1.3 meters long though.

I don't have it anymore. I gave it to a guy at the pond. He is practicing with it now. He will enter his first race next season.

Hammer

 

[Ian Inverarity]

Hammer,

I guess 3.6kg is not too bad then!

Mine is not 1.3m long tho, I am actually not sure what the size is! I hope it stays on the water!

Do you still have the wooden boat you built? Was that any lighter?

Ian.

 

[Hammerhead]

They pink wood one, I just gave it away yesterday at the races. Some guy wanted to race .90 riggers next season, so I gave it to him. It was exactly the same length at about the same weight. Can't remember. but I really made my CF hefty. It had 8 ply sidewalls on the tub. It would probably take a bullet.

Hammer

 

[Ian Inverarity]

Gee Hammer!

You put a lot of work into boats only to give them away so fast!!!

I have read on other forums that at least for riggers there is little or no weight advantage to using CF for hulls insted of wood. My hull is CF over wood! It wont take a bullet tho....

Ian.

 

[Hammerhead]

Well Ian, there are several reasons that I give my boats away. The biggest reason is; my wife refuses to let me make our house into a warehouse for boats that I will probably never use again. Other reasons are as follows. Having no boat, gives me the inspiration to build another that is better. By giving boats away, I am giving people a chance to get a feel for the hobby that they would have otherwise given up on, due to the price. And last of all, it just feels good to someone enjoying something that I made.

I will come up with something more spectacular for next season. Just you wait. " No Left hooks though" I prefer the standard type. I learned some interesting turn fin tech stuff. I'm looking forward to incorporating it into my next hydro and sharing the results in this forum.

Hammer

Hammer

 

[Ian Inverarity]

Hammer,

You are a very charitable man! I try to get rid of my old stuff too, but I generally sell it to make it easier to get the next boat!

I was talking to a friend at the races on Sunday about the principles of the left hook boat and why I thought it was a very good idea. He agreed with me. He is a very experienced boat racer, he still uses a rope to start his motors, and I have seen him start a K&B 21 outboard by hand and start his 40 mono by flipping the prop!

I have an idea how to use a variant of the design to build a good twin, so I am trying to track down a pair of small motors like 21's or 45's so I can build a quick-n-nasty prototype before getting serious and building a proper one with two 90's.

I also have some ideas on sponson geometry and unusual turn fins that I want to try too...

I look forward to seeing your ideas!

Ian.

 

[Hammerhead]

Ian! I was talking to Rocky about the left hook at the nats. We were saying that it would look pretty seductive if it had both a right and left hook. Put the transom in the crotch. Guess what! He is in the process of making one. It will have one engine turning a double gear up box. It will have to props counter spinning. It will be a 4 point. with the props close to the CG. Can't wait to see what it looks like. I thought he said, but I can't remember for sure, he was talking about an A 90 this time. I ran against an A90 in a Microburst last Sunday, but I blew him away. His engine was screamin' nicely, but he needs to think about gettin' a Kingcraft before he messes with me again. ;D

Hammer

 

[Ian Inverarity]

Hammer,

Wow, that sounds different! The idea I had for a twin was to have the tub wide at the front, but stepping in narrow in the middle and having the props either side of the tub where it narrows down. For a single engine boat my idea was to have the left sponson extended to incorporate the rear sponson as well, have a short engine pod in the middle and a normal right hand sponson. I am more interested in doing a twin tho, I am pretty sure a twin 90 of this principle will be unbeatable in any water.

The stock A-90's are a bit funny. They keep changing the spec on them, but the inlet duration should be increased to 215 degrees closing at 65 ATDC. Also the inlet passage behind the carb into the motor should be enlarged and smoothed out. They keep changing the cylinder timings so I cant give any recommendations there. Also the head volume is very large on some motors which might be a problem unless a lot of nitro is used. Correctly modified and they are awesome..... ;D I have a new one that I have just finished modifying that will be runing in my current rigger very soon.

Ian.

 

[Hammerhead]

Hey Ian! If you want to see the Left hook in action, it's video is posted in the JMPBA 2002 Vid thread. Check it out.

Hammer

 

[Ian Inverarity]

Hammer,

If I get the time I will download that video, but it is pretty big!!!

I ran my A-90 powered hummingbird this weekend. The engine is still very new, but the boat was quick. My setup was wrong tho, it was too loose and it blew off in the first corner I tried to take at full speed! It barrel rolled and smashed the sponson booms! Oh well, that's racing! : Welcome to the world of CF booms!

Ian.

 

[TimD]

Tim,

I think I have one of those blanking screws from when I bought a couple of 9B remote needles. It's of no use to me....

Ian.

Ian,

If you still have one of them can I get it from you b4 the nat's? The Carb is going onto the Picco tonight and the BVM needle valve is going into the tub close to the carb, but space is pretty limited with the stock 9b needle still mounted to the carb.

Cheers,

Tim.

P.S thanks Hammer for the carb!

 

[Ian Inverarity]

Tim,

Email me you address, I have to go to the post office tonight anyway.

Ian.

 

[TimD]

Thanks Ian,

You got mail!

Tim.