General Hydro info.

[gooycheese]

Hi All,

This winter I will be rebuilding my .12 blazzin and will be building a FF.21 . The questions I have are :

1. I have seen alot of different types of boom tube blocks and mountings and collars for holding the sponsons on, if the hydro guys could please post some pics/links of how they are setting up the front ends of there boats that would be awesome?

2. I have seen alot of carbon fiber used in builds, is carbon fiber used as a doubler over wood ( on the tub sides) and if so how hard is this to do "will it be stronger/lighter"?

3. Vacuum forming cowls, how hard is this? Is there a link to how this can be done?

I know I will have more questions, the first 2 are my main priority now. I want to know exactly what i plan on doing before I even start to build.

Thank You,

Paul

 

[Olly]

Here are a couple of websites I have found on vacuum forming:

http://members.aol.com/KMyersEFO/vacuum.htm

http://members.aol.com/GCGassaway/vacuform.htm

Hope they help.

Olly

 

[Dan_Cousin]

Gooey,

I put a 1/2" wide strip of plywood under the boom that goes from tub side to tub side. I cut a few water/fuel passageways tunnels on thebottom of the piece so fuel and water can drain between this peice and the bottom of the tub.

Once the booms are in place and set, I drill and install two threaded inserts per boom (8-32 for .45 rigger and up) in the strip. To hold the booms, just used a socket head screw with a little blue loctite and you're set.

I design mine with a slightly high angle of attack (rear tube lower than normal) and shim during initial trimming.

 

[waltr]

Hi All,
This winter I will be rebuilding my .12 blazzin and will be building a FF.21 . The questions I have are :

1. I have seen alot of different types of boom tube blocks and mountings and collars for holding the sponsons on, if the hydro guys could please post some pics/links of how they are setting up the front ends of there boats that would be awesome?

2. I have seen alot of carbon fiber used in builds, is carbon fiber used as a doubler over wood ( on the tub sides) and if so how hard is this to do "will it be stronger/lighter"?

3. Vacuum forming cowls, how hard is this? Is there a link to how this can be done?

I know I will have more questions, the first 2 are my main priority now. I want to know exactly what i plan on doing before I even start to build.

Thank You,

Paul

Paul,

If you would like, I can mill a radius for the tubes in the boom tube block for you when your ready. I already have 1/2" marine plywood home. Just tell me how tall and wide you'll need and you're good to go. If you want to make the rear tube adjustable, I can also do Delrin blocks to sit ontop of the ply that you can shim for adjustability.

Forget about the Exterior carbon on the tub.For it to come out like my Hummingbird, I believe it should be vacume bagged.

Mike Coppolino,PHM, did some also. Don't know if he bagged them or not. Maybe he'll look at this post and reply.

 

[gooycheese]

Thanks Everyone,

I am going to start building this rigger on the 1st of January, It will be part of a build challenge on another forum. Until that time I will be trying to scrape all the pieces for it together so when its build time I don't have slow down points. I have been thinking about all different types of scenarios for this build but after seeing Marty Davis's post asking about weight my main concern will be weight. I will try an do the build and have the final weight between 3 3/4 - 4 lbs, closer to 3 3/4 if I can do it. About milling Walt if I get to a point where i figure milling will be needed I will get ahold of you thank you .

Thanks Again Everyone,

Paul

 

[Preston_Hall]

If you read other sites about how to vaccuum form with a shop vac..................forget it. Waist of time and money. I tried it. You need a vaccuum pump and a tank to use as a reservoir. The vaccuum action must be fast.

For the sponson tube block in the hull I usually use the hardwood sticks from the LHS.

Boom tubes from Lone Star Balsa.

You can go here and see how I built a boat. If you want to save weight then apply expoxy the way I describe. You should be able to sort the pics since they are numbered.

 

[gooycheese]

Thank You Preston,

I will definitely refer to your link and pics while i build my next rigger.

Paul

 

[Tofastformellow]

Gooey,I design mine with a slightly high angle of attack (rear tube lower than normal) and shim during initial trimming.

Ooooo, thats interesting , and i agree with this, i have been playing with the rear boom height (ie lower than setup ) in my sg's and am having some radical results..

but it helps older, lower powered motors more

Jase

 

[gooycheese]

Hi All,

These questions I assume would fall under the general hydro info topic

Ok I built a B hydro, FF.21 / NR .21 SS / OPS3280 7 7/8" / 1445 s/b / 60% / Flat Strut

At first I had the pipe at 8 3/8" and I had 2 - 1/16" shims under the rear boom (max speed was about 52mph). Was told remove all the shims till its gonna blow off and and to bring back to control and shorten pipe. Well I shortened pipe and remove 1 shim boat did blow off 63mph (water wasn't perfect but i don't like testing on glass). My problem is the tail of the boat looks real wet and the front is up in the air in my opinion the boat doesn't look flat on the water. Before I start adding a 1/32 shim under the rear boom I was wondering if I put a little positive angle in the strut would that raise the rear and bring the front down at all? Please Help if you see something I am doing wrong or if you have suggestions for me.................... or if I am just and idiot ................lol

Thank You ,

Paul

so far best prop is H7 or 1650, have not really tried a modded prop yet. Have tried H5,H7,H10,1445,1450,1650,1816 and a couple Aussie props don't remember the names of them.

 

[TomMoorehouse]

we could try adding 1/8" shims to both the front and rear tubes?

 

[Chris Wood]

gooy

you need in my opinon a min of 1.5 negative strut angle.. try that.. running a flat strut i believe is part of the problem.

take all you shims out of the rear tube.. put the strut 1.5 neg to whatever hight setting you have.. i would start with the strut flush with the rear sponsons and go from there.

chris

 

[gooycheese]

Hi All,

Just wanted to put a couple pics up of the boat I built this winter. I hope it does well this year.

Paul

 

[Tofastformellow]

on my FFr s i set the strut angle down with the attack of the rear sponsons , and set the strut depth so the centre line of the drive is set to the bottom of the rear sponsons ...

clear as mud ?

Jason