Riggers from Japan

[Hammerhead]

Hey Tim, isn't Nelson the Pylon engine maker. I used to have one of those about 6 or so years ago. It was a .90, and, it had tons of power, but it had rear exhaust like the .21s do these days.

I had trouble with mounting the pipe, so I gave up and sold it. Right now I'm thinking about making a O.S .46 into a .47, so I can run C-Hydro with it. It has been done, and the results are unbelievable. How it is done is by milling down the crank shafts connecting rod pin and replacing the connecting rod with a custom made one. It will give you just enough exhaust volume to bump you up to the next class. Then you will be able to use a smaller and lighter boat with about 6000 more RPM. Another thing a lot of people are doing over here, that Dennis Cessna might be interested in, is air cooling. It seems that water cooling makes the expansion of the liner and piston inproportionate. What do you think? One of my buddies made a custom head for his .81 O.S.. It looks like a Racng car cooling finned head. He seems to have an easier time getting good needle settings, and he can run a race with the boat at full throttle, using a third channel to control the speed in the straights by leaning it out, and riching it out in the corners.

Very interesting. He said that he tried the same technic with water cooling, but couldn't get the distinct response. He said, he thinks it is because of inconsistant expansion of the moving parts at unbalanced temperatures. I think I will try it someday. Wow! SOunds a little too technical coming from the mouth of someone who is retarded when it comes to engine tuning.

Hammer

 

[TimD]

Hey Tim, isn't Nelson the Pylon engine maker.

Yes Hammer, it is! see this link. http://www.pspec.com/

[quote author=Hammerhead link=board=1;threadid=216;start=135#2264

Right now I'm thinking about making a O.S .46 into a .47, so I can run C-Hydro with it. It has been done, and the results are unbelievable. How it is done is by milling down the crank shafts connecting rod pin and replacing the connecting rod with a custom made one. It will give you just enough exhaust volume to bump you up to the next class. Then you will be able to use a smaller and lighter boat with about 6000 more RPM.

Hammer, those o.s 46's are rear exhaust right? why not put it on a gear drive setup with a super short pipe - gear the thing in reduction and swing a bigger prop! I'm doing this with a 21 mono and it hauls A$$ .

[quote author=Hammerhead link=board=1;threadid=216;start=135#2264

Another thing a lot of people are doing over here, that Dennis Cessna might be interested in, is air cooling. It seems that water cooling makes the expansion of the liner and piston inproportionate. What do you think?

Hammer - been doing that too on 21's - works VERY well, but I'm not so sure about the bigger motor's - might get too hot! I'd like to hear more results before I'm sold!

[quote author=Hammerhead link=board=1;threadid=216;start=135#2264

Very interesting. He said that he tried the same technic with water cooling, but couldn't get the distinct response. He said, he thinks it is because of inconsistant expansion of the moving parts at unbalanced temperatures. I think I will try it someday. Wow! SOunds a little too technical coming from the mouth of someone who is retarded when it comes to engine tuning.

Hammer

Reducing the cooling amount by rstricting the water is another way of achieving similar results and easier than making a finned head.

 

[MikeP]

Hammer,

What do you use for tape on the sponson tubes?

-Mike

 

[Hammerhead 90]

Hi Mike!

I use electrical tape. It has some elasticity, so it it can really hold well. It also sticks to its self well and it is easy to take off as well.

By the way, I will try to send you another can this weekend. I was too busy with work to get to the post office. I hope I can get it to you before you need it.

Hammer from the office.

 

[TimD]

Hammer,

What tuned pipe are you using on the 90?

Tim.

 

[Hammerhead]

Hi Tim!

I'm using a Macs 13cc pipe with a TRK silencer on it. They pipe isn't a quiet or super quiet type. Just a straight tuned pipe. It is cut to 27.5 cm from the plug to the widest piont of the pipe. I also use K&B HP plugs. For fuel I use Odonnel 45% usually, or sometimes, when I can get my hands on some, I use one of my buddies home made brews. It is 43%, but it has just a little more oil in it. I think he said it was 21% oil. Where I think Odonnel is 20%. I really can't tell the difference in performance , but I think Odonnel makes my fuel hosed age fast.

Have a good weekend. I will be entertaining the family this weekend, so no boating for me.

Hammer

 

[Hammerhead]

Well Tim,

here it goes. Air cooled .81 got 18.7 seconds in the 4 lap time trials. The .47 which ran in the same class got 17.2 seconds. Each lap is 100meters for a total of 400 meters. They were using infra red to start and stop the clock. Looks like if I ever get involved in the time trials, I will go with the .47. For now, I have too many other projects on my mind. Number one is Electric SAW. I already started designing the boat. It will be made of 1mm 3ply yellow birch.

I have to beat 72 mph. The record got bumped up this year. I think I can do it with 18 cells.

Thanks for your comments on the .47 and the air-cooled .81

Gearing down cost too much money for the results you get. The unit also weighs a bunch. That is my opinion. I have seen tons of them here. None of them have ever impressed me to the point where I felt that I had to go out and get one.

Have a good one.

Hammer

 

[TimD]

Hammer san,

I see what you mean about the time difference from the .47 to the .81.

Did the aircooled .81 get very hot??

Tim.

 

[Hammerhead]

I've seen him run the .81 at the place where we practice. The entire head is exposed, so it didn't get very hot when I saw it run. I'm not sure, but maybe having so much of his engine exposed created the second or so that he lost in the time trails. ( Bad aerodynamics). On the 4th of August, I'm going to take my Hammerhead to the pond where they have the time trials. They are having Newbee Day. Anybody can go and see how fast there boat is. I don't think I will break 20 seconds, but it will be interesting to see just how much difference there is in my hull and a Time Trial Hull.

(Officially that is) This weekend I will try the 1667 again. The weather is supposed to be nice, with little wind, so I will be able to make an honest judgement.

Hammer

 

[Twin_k90]

HammerHead,

Have you tried ABC Props?? if your running a 1667 try a H38 you will pick up lots of speed if thats too small try a H48 you should run over 90mph with the 48 at good revs

Dale

 

[Hammerhead]

Hey K90, Thanks for the tip. One problem. It is really hard to find a good selection of ABC props over here. I tried one of my friends H38s before with a different boat than I'm using now. It was about the same as the 470. I can't really tell the difference. We don't use a radar gun at our pond often. I've gotten over 90 with a 270 and the 470 before.

I have a prob with lift. How do the ABCs lift?

Thanks Hammer

 

[Twin_k90]

Get them straight from Jim at ABC thats what i do.

the h38 has about the same lift as a 1667 and is pretty much the same prop but the h38 is a lot faster. the H48 has more lift again and they work a treat on my twin, im waiting on some h50's to arrive soon, if you are having lift probs drop the strut a bit to raise the back of the tub up,

 

[Hammerhead]

Hey K90! I tried dropping the strut a bit. When I did this, the engine wouldn't turn the 270 in the straights. When I would come out of the corners, it would dog down the engine. I raised the strut and it stopped dogging down. I lowered the strut, and dropped down to a 265 and it handled perfect, but I lost the desired speed. One of my buds said, " Octuras have more lift. I tried the 470. It has more lift than the 270, but TimD says, that the 1667 has more. I tried both, but the 470 seemed to have more. Hmmmm! Maybe I need to have the balance of my 1667 checked. I did it myself. That might be the problem.

Thanks for the info. I know a guy who has a lot of ABC props. I think I will take your advice, and borrow a few and see if I can find a good one.

Without the lift. It seems to run like it is on the edge of blowing over, but it doesn't. Maybe it will be okay just the way it is. This weekend I will get it into the water with some of my buddies and have a mock race. This way I will be able to see if it will stay on the water in a heat. If it stays put, I might just leave it the way it is. All my friends say it should be fine. Just a little nervous, I guess.

Let you know what happens.

Hammer

 

[Mike]

Very interesting thread.

Im interested in those monos. Wings and all wow Can you give any details on rules, speeds, etc?

Thanks

Mike

 

[Twin_k90]

If it bogged down with the 270 it is a bit big to run lower, the prather props are not much chop on a good hydro, the H48 running up high shouls still give you good lift and you should be able to pull it. another thing to try is putting some rear sponsons on the boat to take the load off the prop a bit, i had rear sponsons on my old eagle with MAC 84's and i couldnt pull h38's then again some motors just dont want to pull props.

Generally if you pitch a prop up you will loose lift, so try not to pitch them up too much.

There are also H31 (big prop), H32, H38, H45 (im waiting on some to try on the twin), H48, H50 there is heaps there to try, usually a CMB 100 will run a H50.

Dale

 

[Hammerhead]

Mike! (Guest Mike)

Don't want to get you mixed up with MikeP .

Thanks for the compliment on the thread. I haven't really talked too much about monos in my thread. Did you look at a Japanese homepage or something? Are you interested in the rules for offshore, time trials, or heat racing. I'm strictly a heat racer at the moment, but I have staffed some of the other events so, I'm familiar with the rules. Could you be more specific on what you want to know.

I can tell you that the monos in off shore use wings. They are connected in sequence with the throttle in most cases. Don't see too many these days. A lot of the offshore guys are using helicopter gyros to control trim tabs. If the nose lifts up to much, the gyro tells the servo to lower the trim tabs. Simple application, but very pricey. I know of one guy who uses it in heat racing with a hydro. If his sponsons bounce up, the rudder will counter instantly, so it will come right back down. It has saved him more than a few heats.

Mike! Become an INTERNATIONAL WATERS GUY, and enjoy the fun! We are a bunch of good guys.

Hey Dale! or do you prefer K90?

I'm all charged up and ready to go. I got a hold of the ABC freak. He will bring a whole mess of them tomorrow for me to try. I looked at the charts. It looks like the H38 is the way to go!

See ya tomorrow.

Hammer

 

[Mike K]

Thanks Hammer..

Tried to register but could not..

Im interested in gas mono racing, so the heat racers , and how they run is what im interested in. I run a gas seaducer in the mid 50's. The picture of that low profile V catching major air on rough water got me interested because stability in heat racing is a must. The seaducer looks popular there and the other V's have a very similer shape. I like the low almost nonexistant transoms but taller bows for rough water. Do they build alot of those V,s like the riggers, or are most of those available in Japan?

Thanks!

Mike Kolder

 

[Hammerhead]

Hey Mike K! Could you give me the URL for the pic you saw?

If I see it, I will know what you are talking about.

Thanks, Hammer

 

[Mike K]

http://members.jcom.home.ne.jp/rc5t-anzi/

If that link does not take you there, its a page with only monos and the first pics have wings.

So gyros control the wing angle? And tabs? Which kind of gyro would you use?

Thanks

Mike

 

[mikek]

third link from the bottom.

Mike