Scratch Built P Sport Hydro from CAD

[detox]

I hope it has enough height to hold one Hyperion 4s 5000mah pack.

[Shooter]

I hope it has enough height to hold one Hyperion 4s 5000mah pack.

I don't have any Hyperion packs anymore, but I would imagine so. It was designed around the Dinogy 4S 5000. I wanted it to be as low profile as possible and still fit batts way up in the front....

[Shooter]

By the way....that middle cross member frame gets removed. In the sketch (post #1), it is shown running right thru the batts! The 4S 5000 batts are in yellow.

[sean450]

Do you plan on sharing the files for the ones who would like to build your hull. If so I'd like a file in dwg or dxf format. The hydro looks cool. Is it the one in your avatar?

[Shooter]

Hi Sean. Yeah, I can share files, however, I'm going to wait until I complete it and tweak it a little first with some help from our club members as well. I'm not even sure it will float yet! lol!

The boat in the avatar is a Phil Thomas Stealth, with a custom formed cowl that I made to use flat tape.

I've been dragging on this project. I finally ordered wood last night.

[Shooter]

OK, finally received the wood. I was somewhat disappointed with the tolerance of the 1/8" spruce pcs. They are measuring as much as 0.146" on one side! I started measuring other spruce pcs I had laying around and they are running 0.128" x 0.125". I know it sounds like fly $hit, but when they sit higher in the slots, it's not good!!!

Also, talked to Mike the other day about dyhedral. Say what? I thought I was working on a boat not a plane!!! Anyways, it currently has ZERO degrees on each side. Seems to be common to put a greater angle on the outside sponson....maybe to give an airgap so when she leans to the outside in a turn it's still riding on the pad instead of forcing the side of the sponson into the water?? I dunno.... Not sure what I'm going to do yet about this.

[longballlumber]

Leave it alone and build it... It may work, it may not. You won't know until you run the boat... test test test, change change change

Later,
Ball

[siberianhusky]

A while ago I was playing with designing one, got a lot drawn out in cad actually then kind of lost interest.
The one thing I was trying to implement was removable ride pads so I could try different designs with out a complete rebuild.
Maybe something useful, no idea.

[olwarbirds]

Wood, I noticed same thing at hobbyshop on an order we had just got in (basswood) seems the standards (tolerances) dont matter anymore. Ive been reading about dyhedral, we blueprint our hulls etc...then add dyhedral, offset drivelines ........... ? wont adding dyhedral slow the hull down in the straights. wouldnt the hull want to turn inward all the time ? or crab...I am still learning, but ive been a RC nut for 46 yrs .....build straight, then adjust was the way ive done fast planes for yrs....DJ

[Shooter]

Leave it alone and build it... It may work, it may not. You won't know until you run the boat... test test test, change change change

Later,
Ball

Yep...eventually I have to get this thing going. Been stalling a lot.

A while ago I was playing with designing one, got a lot drawn out in cad actually then kind of lost interest.
The one thing I was trying to implement was removable ride pads so I could try different designs with out a complete rebuild.
Maybe something useful, no idea.

That is a really cool idea. I think one of the guys in our club had bolt on sponsons at one point. Ken maybe?

[Shooter]

wont adding dyhedral slow the hull down in the straights. wouldnt the hull want to turn inward all the time ? or crab...

I agree. If it behaves anything like a plane, the dihedral helps maintain stability (that's with equal angle on each wing). You would think only having it on one side would make it lean (better for turns?), but I don't know. Hopefully somebody will chime in.

I remember adding ailerons to a plane with a huge amount of dihedral in the wing and the dihedral really faught the ailerons when trying to bank....dihedral always tried to center it.

[Fluid]

Sponson dihedral controls hydrodynamic lift. More dihedral = less lift. It also can improve turning and rough water handling by having an edge which can dig into the water. Most modern hydro designs do not use dihedral in the sponsons, if they do it is a minimal amount. They get improved performance with more lift from flat bottoms and use the modern 'hooked' turn fin to control turning.

Actually dihedral is probably the least important feature to worry about. Angle of attack and bottom surface area (width) have much more impact on performance. One of our club members has designed about a dozen successful sport hydros from N-2 to T sizes, and at first he often had to change the width or aoa on his designs to fine tune them. Now they usually perform great right off the building table - his last one didn't because he was focused on reducing drag and he used a turn fin which was too small for the hull. After several months of fighting the boat and changing the bottom he finally took suggestions and bolted on a bigger fin. Voila, boat fixed.


.

[Shooter]

Sponson dihedral controls hydrodynamic lift. More dihedral = less lift. It also can improve turning and rough water handling by having an edge which can dig into the water. Most modern hydro designs do not use dihedral in the sponsons, if they do it is a minimal amount. They get improved performance with more lift from flat bottoms and use the modern 'hooked' turn fin to control turning.

Actually dihedral is probably the least important feature to worry about. Angle of attack and bottom surface area (width) have much more impact on performance. One of our club members has designed about a dozen successful sport hydros from N-2 to T sizes, and at first he often had to change the width or aoa on his designs to fine tune them. Now they usually perform great right off the building table - his last one didn't because he was focused on reducing drag and he used a turn fin which was too small for the hull. After several months of fighting the boat and changing the bottom he finally took suggestions and bolted on a bigger fin. Voila, boat fixed.


.

Good info on this. Thanks. The angles on the boat are on par with other boats out there, however, the bottom non vented surface area (i.e. everything in front of the backs of the sponsons) is something I am worried about. This boat has quite a bit. Could make it more susceptable to blow overs. I was hoping the extra length would help me there (dragster approach). I suppose we will see.

[Shooter]

Been putting some time in on the model. The sponson side walls will essentially go all the way to the tips. The center support pc will need to be sanded with the appropriate angles to fit snug. The props we've been running seem to get the boats to jump out of the water quickly, so I'm hoping planing won't be a problem, but again....we'll see what happens when we get it out there! The cowl was sort of a 20 minute joke at first, but I'm really starting to dig it.

[Shooter]

Nothing like coming home smelling like a campfire.

Tried something different. I thought I could cut 1/4" for the center frame, but the curve of the laser is just too much when you get that thick and the kerf was near 0.30mm anyhow. I'm just going to just glue (2) 1/8"pcs.

Trying to figure out how I got this deep into boats. Never ever been this deep.