SPAD Airboat
 

Hey all, I haven't posted here in a while, been pretty busy with work. However over the past 2 days I have constructed a new hull. I did this rather hastily and any future hulls will be more refined. 4 mil coroplast was on sale for $2.99 for a 24" by 48" sheet, the CA cost me more than the coroplast!!! My hull measures 16" wide by 31" long. It has a 10" center ride section with 56 degree tapers to the edge. At the front I have over lapped the piece of coroplast so that the flutes run in the direction of travel and would create air bubbles underneath the hull. here are some pics.

RE: SPAD Airboat
 

Uh-huh ..... I see where your going ..... trying a modified/simplified version of a stepped hull ...;)
VERY good idea . Gotta make sure you let us know how it turns out and runs .

RE: SPAD Airboat
 

:Dlooks good :eek:What kind of glue did you use to hold that stuff to the foam? i used that stuff in the past for other projects i found nothing sticks well to it?

RE: SPAD Airboat
 

Talk about going back to the grass roots of boating....

The first performance hydros were single stepped hulls.

If you look at the full scale (and RC) boating scene today, you will notice that stepped hulls have made a big comeback, not in hydros, but in monohulls.

ha....there is something to be said after all, for the old ways.....:D:D now where did I stash my old Octura White Heat?

I'll be watching for updates, especially on how it runs and turns.

RE: SPAD Airboat
 

what is a stepped hull, are there any advantages of having the hull designed like this

RE: SPAD Airboat
 

Nice!! [sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif]

Yes...Keep us posted!! ....mainly with video!! :D:D

RE: SPAD Airboat
 

Look at the 3rd and 4th pic of his post.

Towards the bow (front) of the hull, on the bottom.

There is a 'step' in the hull bottom when you look at it from the side. The bow portion of the hull bottom sits lower into the water than the rest of the hull bottom. Flip it upside down and it looks like a 'step'.

When traveling over the water, this bow portion raises the front of the hull slightly to introduce air under the rest of the hull bottom. Doing so lets most of the hull ride on an air cushion, with no friction, as compared to a wetted surface. If you ever hear someone say the hull 'airs out', it is in essence riding a cushion of air.

In theory, and practice...

RE: SPAD Airboat
 

My original plan was not for a stepped hull, I had planned to use one single piece for the bottom, however cutting all of the flutes just seems like too much work for my quickie experiment, so i ended up with a stepped hull. When i talked about the air bubb;es underneath, you'll see the flutes are open at the step, if i put hole in the flutes at the very front of the bow then air would run through them and exit at the step further reducing surface drag.....i think. For those of you who don't know what the flutes are, they are the "tubes" inside the two outer surfaces. I used good old CA on this. They recommend flame treating the surface to burn off manufacturing oils for better adhesion. There is a simple water test to see if the coroplast has been pre-flamed, you just splash some on a vertical piece and if it beads up and stay it needs to be flamed if it runs off then it is good to go. Will be awhile before this hull gets its feet wet, I am trying to build an entire coroplast boat and the engine nacelle is going to be tricky.