Roundnose attributes

[SayMikey]

Before I start working on this comming winters round nose project, I thought I would askaround for the best attributes of a successful 1/8 scale shovel. I'm interested in ride pad design

tunnel design and weight distribution or anything to help it stay on the water and perform well.

Thanks, Brent

The beach debate will rage through tthe ages, but in my view the best attribute of a roundnose hydro is substanbtially reduced induced drag. That is pretty much the only advantage a roundnose is ever going to have over a pickle. You just punch a smaller and cleaner hole through the air. That’s why you see the occcasional roundnose bullet up the backstretch. The prop is simply pushing less stufff throughh the air. Aerodynamic drag counts for about 60% of the overall induced drag.

Oh yeah, and they look cooler too. That counts for something, right?

marc

Just curious Marty did you just detoungue the props ? I am currently running a 1460-1462 stock the boat seems to like it,but as you know we all keep looking for more............Mike

 

[Wesleys Custom RC]

So nobody wants to play? How about I get more specific. Is a wide tunnel better than a narrow one? Should I build to the maximun tunnel width or the narrowest? Should I use the standard 3 degrees angle of attack on the sponsons or make it around 1? How much prop weight should I shoot for? Some one must have some experience I can draw from.
Brent

Brent:

You have asked some really good questions.

I should assume from your questions that you have the ability to change the Newton Plans.

I ran a fairly successful Roundnose Miss Vernors for several years and the boat that I had ran about 2 degrees of attack angle and was at the limit on width. As for strut weight, I would suggest that you use as little strut weight as possible. My boat actually balanced only very slightly behind the front sponson ride pad. I ran X Style props so they would hook up well. If I tried to run 1400 series props it would blow the back end of the boat out of the water because of the lack of strut weight.

No need to get carried away trying to save a ton of weight as the round nose boats have a tenancy to blow off and a little extra weight is not bad. I did try to save weight and the boat would sometimes instantly blow off if I was pushing it.

Be sure to put the rudder on the left and make the strut as wide as possible within the rules. You should run a couple of degrees of shaft angle to help the boat lift the transom coming out of the turns.

Hope this is what you are looking for....

Marty Davis

I run a Phil Thomas hull but have come to the same conclusions as Marty. I keep pushing my cg forward and I still use alot of weight. I can rocket my boat down the straight aways but the slightest puff of wind will make it look like a f 16 on take off. Drop the strut a little and it will make a submarine except when it comes back up your beautiful fake motor will be in pieces. If you really want a challange driving a boat that is it. Oh ya, I had Dick Tyndall make me a special turn fin......Made a BIG difference. Call him, he will hook you up :blink:

 

[Marty Davis]

Before I start working on this comming winters round nose project, I thought I would askaround for the best attributes of a successful 1/8 scale shovel. I'm interested in ride pad design

tunnel design and weight distribution or anything to help it stay on the water and perform well.

Thanks, Brent

The beach debate will rage through tthe ages, but in my view the best attribute of a roundnose hydro is substanbtially reduced induced drag. That is pretty much the only advantage a roundnose is ever going to have over a pickle. You just punch a smaller and cleaner hole through the air. That’s why you see the occcasional roundnose bullet up the backstretch. The prop is simply pushing less stufff throughh the air. Aerodynamic drag counts for about 60% of the overall induced drag.

Oh yeah, and they look cooler too. That counts for something, right?

marc

Just curious Marty did you just detoungue the props ? I am currently running a 1460-1462 stock the boat seems to like it,but as you know we all keep looking for more............Mike

Mike:

Some props that I ran, I did remove a lot of the tongue. I found that the best prop by far for my 1/8 Scale was a 62x80 ABC. It seemed to run fast enough that I didn't have to remove the tongue. If I would have gone much faster, I would have had a LOT of trouble keeping it on the water. It was fast enough IF I drove on the buoys and got a good start.

I ran a pitched up 1465 at the Internats for SAW, but launch was really iffy. Would really go fast and that prop tended to keep the rear end up high enough to not allow it to easily blow off. Ran mid to high 60's with that prop.

Marty

 

[WikiWiki1]

This is great information! Thanks everyone.

Brent

 

[SayMikey]

This is great information! Thanks everyone.
Brent

Marty I have a 62x80 and a 60x76 given to me by Brian Schymik. I will try them this weekend as im tuning for The Indiana Governors Cup,im sure your name is on the cup. With a few concourse awards im now after some final wins,this Cup could be my first real win. I need to hone my milling skills and learn to stay in lane 1-3 unless deadwood is there.. Glad to see you hitting the oval again.........Mike

 

[Marty Davis]

This is great information! Thanks everyone.
Brent

Marty I have a 62x80 and a 60x76 given to me by Brian Schymik. I will try them this weekend as im tuning for The Indiana Governors Cup,im sure your name is on the cup. With a few concourse awards im now after some final wins,this Cup could be my first real win. I need to hone my milling skills and learn to stay in lane 1-3 unless deadwood is there.. Glad to see you hitting the oval again.........Mike

Mike:

Work on the turn fin and ability of the boat to go through the turns without losing much speed. That is something that I worked with Brian Schymik on a couple years ago and it had really paid off for him.

I might be on there under the Probe and Miss Vernors. (BOTH Round Noses)

Marty Davis

 

[SayMikey]

This is great information! Thanks everyone.
Brent

Marty I have a 62x80 and a 60x76 given to me by Brian Schymik. I will try them this weekend as im tuning for The Indiana Governors Cup,im sure your name is on the cup. With a few concourse awards im now after some final wins,this Cup could be my first real win. I need to hone my milling skills and learn to stay in lane 1-3 unless deadwood is there.. Glad to see you hitting the oval again.........Mike

Mike:

Work on the turn fin and ability of the boat to go through the turns without losing much speed. That is something that I worked with Brian Schymik on a couple years ago and it had really paid off for him.

I might be on there under the Probe and Miss Vernors. (BOTH Round Noses)

Marty Davis

A HUGE THANKS MARTY the 62x80 woke my boat up. I ran it today with a fresh Greeny and WOWZERS. Mills good and Accels all the way down the straight. I can smell the Governors Cup but can i keep my wits ,we will see next weekend. Again Thanks for the tip...........Mike Schindler 73 RedMan