Do any of you guys remember..??

[wilga12]

 

 

Hi Everyone..............................I'm Dave,............ and I'm new here.

 

A new acquaintence of mine, Tom, at "Firefighter Boats" sent me this way to ask a question of you all:

 

Back in about 1997, (RCboat modeler) Tom felt that He'd seen an article on a "RIGGER STYLE" boat that was driven over the water by an air prop. And it is possible that this article was about a boat that existed in Japan. I "Mailed" Tom the other day,asking him if his GAS rigger would do the deed,he wasn't sure. As the engine that I explained to him that I was most interested in using, was glo fired, 30cc's,weighs 4 and a half pounds (With prop,mount and muffler) and would swing a 16 inch dia,three blade "tractor".. prop.

 

To aid you in your confusion here,I'd better also state that I'm part of another bunch of guys in an "Airboat forum" and that we're engaged in an informal competition to go (Straight line) as fast as we can without blowing over..............Of course,driven by an Airprop.

 

 

I'm really hoping that some of this will ring some bells with you guys,I'd love to find that article,

(or something in subsequent articles on the same subject).

 

I'd like not,to have to re-invent the wheel,if you get my drift..??

 

 

IF you fellas' would just take 30 seconds,lean back in your "Puter" chair,and give it some quality "think time"....................I'm real sure that I'll see that Tom was correct, to send me your direction.

 

 

A BIG Thank You,fellas............................................Dave

 

 

.............Life happens between full and empty........................NO..??

 

[missbudpilot55]

Dave, I vaugely remember the boat you are refering to. Question one is: Single or twin cyliner 30 cc engine, Two: Do you intend to mount the engine on a pylon on the rear of the boat or belt drive the prop with the engine mounted low in the hull to keep the center of gravity low?

Some considerations, Tom's Fire Fighter Gas hydro would have to be totally redesigned to accomodate your intentions of powering the boat with an air prop, ie the sponsons would have to be moved to the rear of the hull, "ala" canard style to accomodate the torque from the engine and air prop (tractor or pusher) and the forward section or nose of the rigger tub would have to have a "planing shoe" built on the front of it for forward stability.

The boat you are referring to and some other "Air-Powered" rigger type I have seen through my many years of modelling have been very streamlined simular to some of the control line speed models from back in the 60's & early 70's.

 

[wilga12]

 

 

Hey Bill ....................................Thanks,for the reply.

 

 

The engine will be a single, Likely mounted inverted, on a pylon. .................. Yes, I do realize that this configuration has its dissadvantages, But,as I said earlier, this will be a straight line speed attempt.

 

I mentioned Tom's Gas Rigger, as mostly a reference point or starting place for initial ideas. He mentioned that it's only 42 or 43 inches in length. So, I'm guessing that would make the riggers c.t.c. distance about 20 inches. In my layman's eyes, considering the punch that the motor has, I'd probably start out by scaling Tom's Gasser up by 175% and then "cut and try",from that point.

 

 

...............................Dave

 

[John Finch]

The boat you are talking about from Japan did not have an article written about it. It was just a photo in the magazine. It looked more like a plane with sponsons. The photo won't do you much good as far as designing a gasser.

 

[John Finch]

I looked thru my magazines but didn't find the photo. If I remember right the engine was on a pod like you would see on an airplane that is designed to land on the water with the engine right above the wing.

 

[missbudpilot55]

 

 

Hey Bill ....................................Thanks,for the reply.

 

 

The engine will be a single, Likely mounted inverted, on a pylon. .................. Yes, I do realize that this configuration has its dissadvantages, But,as I said earlier, this will be a straight line speed attempt.

 

I mentioned Tom's Gas Rigger, as mostly a reference point or starting place for initial ideas. He mentioned that it's only 42 or 43 inches in length. So, I'm guessing that would make the riggers c.t.c. distance about 20 inches. In my layman's eyes, considering the punch that the motor has, I'd probably start out by scaling Tom's Gasser up by 175% and then "cut and try",from that point.

 

 

...............................Dave

 

175% seems a little bit too much, that thing would be almost 6 1/2' long at that scale-up. Another thing came to mind, how are you going to steer this air boat, air rudder or water rudder or both? and what speeds do you hope to attain? 4 1/2# is a lot of weight on a pylon and the torque of the motor will definatly be a challenge to balance the boat while running so the stance of the sponsons would have to be very wide and possibly off-set a bit for torque stability. I'm guessing that double the diameter of the prop for sponson stance, = 32" from inside to inside measurement would be a good starting point. Length of the hull somewhere around 54" is where I would start at. Some food for thought, if I were doing this project I would belt drive the prop and mount the engine low in the hull and possibly under or over-drive the prop. Have you tached the engine with this particlar prop on it, if so what RPM's are you turning on nitro and what percentage are using?

 

By the way Dave what part of the country are you in?

 

[Hammerhead]

・Ｆクラス（エンジン７．５ｃｃまで、空力プロペラ使用で船型自由）

（Ｆクラス以外はスクリューによる推進方式による）

I'm not sure if you can read this, but this is the boat that you are talking about. It is a 100m time trial boat that is called the F-Class in Japan. It's engine is only a 7.5cc (.45) It has records as high as 108 mph in Japan's JMPBA. It has the engine generally mounted on a composite tripod. There are usually aerodynamic cowlings around the engines as well. Other than this, they are very similar to an outrigger.

This class is no longer very popular in Japan. I tried very hard to find photos but had no luck.

I did have the RC boat Modeller that had the pics that you are talking about in. That was a long time ago.

Hammer

 

[Ivy McNeil]

Dave, I vaugely remember the boat you are refering to. Question one is: Single or twin cyliner 30 cc engine, Two: Do you intend to mount the engine on a pylon on the rear of the boat or belt drive the prop with the engine mounted low in the hull to keep the center of gravity low?

Some considerations, Tom's Fire Fighter Gas hydro would have to be totally redesigned to accomodate your intentions of powering the boat with an air prop, ie the sponsons would have to be moved to the rear of the hull, "ala" canard style to accomodate the torque from the engine and air prop (tractor or pusher) and the forward section or nose of the rigger tub would have to have a "planing shoe" built on the front of it for forward stability.

The boat you are referring to and some other "Air-Powered" rigger type I have seen through my many years of modelling have been very streamlined simular to some of the control line speed models from back in the 60's & early 70's.

Hi

Here is some pic's of the boats from Japan.

Regards

Ivy McNeil

 

[wingnut]

you got a link for the airboat forum?