Riggers from Japan

[Hammerhead]

Looking good Gene, Thanks

 

[TimD]

Hammer san,

The SG is still at the painters :'( The guy who is painting it for me got very sick and wound up in hospital! Apparently it is primer'ed and ready for the colour coats - I'll still send you the pic's as promised! Sorry for the delay.

Tim.

 

[Hammerhead90]

From the office. How's it going. I finally got to take the new Hammer head out to the pond. Did much better in the straights than the carbon fiber version. Not as much down force. I raised the sponsons in relation to the bottom of the hull considerably. This is the main reason. Now I am able to turn the 270 that I have tweeked a bit. Our radar gun is very old. And the reliability is questionable, but I got it up to 94 miles an hour yesterday. I felt that it would of stretched maybe 10 more, but I was lacking space due to low water. Thinking about putting a spoiler on the left sponson. It seems to rise off the water just a little too much for comfort. Especially when I hook out before I attack the 3rd bouy. I decided to try the spoiler first, because I'm afriad that if I angle down the strut, I wont be able to turn my 270 like it does now. Doesn't look like I can post pics for a guest status, so I will post some when I am not at work.

Happy as can be, Hammer

 

[Hammerhead]

Here are some pics of last Sunday. Unfortunately there were no pics of it on the water. The first pic is of it with it's cowling on just after a run.

 

[Hammerhead]

I'm sure a lot of you are interested in what the bottom looks like. I know this is against security regulations, so don't tell anyone.

 

[Hammerhead]

In the previous pic you can see that the turn fin sponson is clearly wider than the other side. This really has an effect on the torque pull. I think it effects it more than bending your strut mount.

The last pic is of the out drive. I made this strut out of stainless steel. It uses dry metal pipe instead of roller bearings. My theory is: wet roller bearings actually are worse than having none at all. You can tell by looking at the wear on the shaft after a long run on each type that there is a lot more friction imposed by the roller bearings. Prove me wrong if you don't believe me. After all this is my opinion, not a scientifically backed statement.

Get some vids on here next Sunday, if the vid guy comes.

Hammer

 

[TimD]

In the previous pic you can see that the turn fin sponson is clearly wider than the other side. This really has an effect on the torque pull. I think it effects it more than bending your strut mount.

Hammer, I'm interested to know more about the different size running surfaces on the sponsons. I hope I'm not asking you to reveal any secrets here - but how wide is the running pad on each sponson on the 90 rigger? Was this achieved from trial and error or is it a known factor?

Tim.

 

[TomMoorehouse]

another sponson question

Hammer.... I am trying to understand the sponson design as well.... i was expecting the cut up to have a sharp angle... like an eagle sg. what is the idea there..... is it more like a step than the end of the running surface?

did you build this one out of wood?

 

[Hammerhead]

Hi Tim! Just joking about the secret stuff. If you want the detailed measurements. The total width of each sponson is 7.4 cm. The turnfin side is angled down to a running surface of 6 cm and the other side is 5cm. The sharpness of the angle is on the outer sides of the sponsons is less on the turn fin side. Actually, you don't need any angle at all on the turn fin side. Even if you do have one it has absolutely no effect what so ever. Remember, these boats are designed to turn left. The only reason I put one in it, is because it gives the looks some balance. Looks kind of corny with out it.

To answer your question Tom, The extension you are seeing is not a step. It is just an extension to accommodate space for the sponson arms. If I would have made it lower, closer to the same level as the running surface, it would have messed up my center of balance. I think it looks cool, too. ( imitation step) No effect on the running characteristics.

If you look at the side view of the boat, you will notice that it angles up and away to prevent water from churning up under the turnfin stablizer. This will cause problems. If you remember the vid of the other hammerhead, you will know what I mean. This is one of the major changes I made with the new version.

Thanks for the inputs.

Hammer.

 

[Hammerhead]

Sorry Tim, I got this idea about 8 or so years ago. I tried it with one cm difference on a .45 hydro, and it worked well. I have use the same measurements ever since. You could say it was trial and no error, because I was impressed with the effects the first time I tried it. I've never tried it before, but I think if you made the difference anymore drastic, it would probably give you an opposite pull. That would make it really fun trying to trim your boat.

Hammer

 

[Hammerhead]

Right now I'm turning a 270. It has been tweeked, so it is probably somewhere between a 265 and a 270 (stock).

Haven't met anyone over here that is keen on Octura, and I am a little paranoid about spending a lot of money on a bunch of props so I can hit and miss until I get the right one.

Could someone tell me one prop from Octura that will be compatible with what I'm running now. I have tried the V series stuff. I borrowed some from my freind. They had to much lift. My boat's transom was flying all over the place. Any info appreciated.

Hammer

 

[TimD]

Hammer,

I would reccomend the octura 1667 to start. Great prop. Not as savage as the V series.

Tim.

 

[Hammerhead]

Guess what Tim, I was heading down to the boat parts shop yesterday. Nobody had answered my request for help at that time, so I searched for some prop charts on the net. I went MartysRC's They also recommended the 1667 and the X670. I bought both of them yesterday, and just finished polishing them. I will give you the results on Sunday. I also bought a X665 just for kicks. Just incase the others are too heavy. I wish that the barrel on the 670 wasn't so darn fat though. It is larger than my strut case.

Thanks. Hammer

 

[TimD]

Sorry Hammer - I wasn't on-line yesterday.

Some other prop's worth considering are the ABC H32 & maybe the H38. Both are for 1/4 shaft's.Motor's with needle roller rod's like the MAC's and CMB's seem to prefer the 1662 Octura, But I think this might be a little small for your O.S. Keep a close eye on your conecting rod bushing with the smaller prop - My O.S. 91VRM spun the bushing in the rod.

Please keep us posted with your results.

Tim

 

[Hammerhead]

The O.S I use is custom made. It has a completely different sleeve, and it has an RPM connecting rod. Do you think that will help? Everybody here pitches their stock rods and replace them with RPMs before they even mount them in their boat. Never have used a stock rod myself.

What do you think. Are the RPMs popular over there? Both my piston and sleeve are tuned AAC. I think that is the same as the MAC engines. They are a B##%ch to break in, but I have never had one seize up on me. I'm pretty good about breaking my engines in.

About my last post. After sliding the X670 onto the shaft, it's barrel is exactly the same diameter as my strut shaft. It looked awfully big in the package though.

Thanks. Keep you informed on the results.

Hammer

 

[Hammerhead]

Hiya all. Well, Today went great. Got the speed I wanted. and the Octura X670 gave me the lift I needed. Guess I'm ready to go. the 1662 and the 670 were almost the same, but the 670 seemed to lift more. I was able to scream along with no worry. The boat was just much more stable. I'm no pro on the octuras, so I have no idea why this is so.

Thanks for your help Tim. The vid guy didn't come today. Sorry! No vids. Maybe next time.

Hammer

 

[TimD]

Hi Hammer,

Very interesting posts lately!

The X series prop's are supposed to give less lift than the 16 series!

I still think the 1667 prop will be the one to try - As long as the motor will pull it of course!

The RPM rod is much better than the stock one - but are starting to get rare. I have one in my Picco.

Can you tell me some more about the AAC Piston and liner as this is the weak area of the motor. Who makes it - how much $$ - available to buy etc. etc..

Tim.

P.S the MAC's have an ABC liner!

 

[Hammerhead 90]

Hello! I will check on the AAC piston and liner. I know that they are made in the states. I don't think they are that expensive. It costs about 110 dollars over here to replace them. I think that it would be even cheaper in Australia or the states. Anyway I will check when I'm at home and mail you the info. About the rods: If you are having trouble getting RPMs, Check out the RC.com forum. There is a thread about another company that is making titanium rods. They are 80-100 dollars. There aren't any O.S rods listed, but if you ask for one, they will make it. Check it out.

Hammer at the office.

 

[Hammerhead90]

Hey Tim, I spent about an hour looking for info on AAC pistons and liners. I found a lot of info about them and some pages that sell engines with them installed, but nothing on where you can buy them seperate. ???

I called the guy who sets up my engines, and appearantly, he also gets the whole engine with the AAC components already installed. When I send my old engines in to get them replaced, which I haven't for ages, because the just don't go bad. He is sending them on to the dealer who does the replacement. DEADEND there too. Hmmm. Somebody out there have any info? Let us know. I did get confirmation that they are made in America.

About the previous post, There is a Typo. I didn't use the 1662. It was a 1667. I was having needle problems, which turned out to be garbage in the carb, when I had it on. I will have to try it again next week. You seem pretty sure that this is the prop, so I think I better take your word for it, and give it another shot. Maybe I can lower my strut. Anyway, we'll see.

See ya around,

Hammer at the office

 

[TimD]

I think they are made by Nelson? There was also aplasma coated P&L sold by Saturn Hobbies.

The 1667 is a pretty common prop with the larger engines - you may need to tweak it a little to get it right.

Tim.