Homebrew Mini V Hull with Outrunner
 

Hi there,

I’m new to boats (mostly fly slope gliders) but I’ve mean playing with this little concept …. Just something to mess around with.

Specs:
Length 14”
Beam 4”
Deadrise at transom: 11 degrees
Motor: TowPro Brushless Outrunner 2408-21 Delta
https://www.unitedhobbies.com/UNITED...idProduct=4321
ESC: A 12A
Battery: 8-Cell 1100mAh NiMH

Here are a couple questions:

1. Will a boat like this need lifting strakes or chines? See Pic. What’s the best way to make/add them?

2.What’s the best way to shim a threaded 3.2mm motor shaft to fit a 1/8” solid coupler
http://www2.towerhobbies.com/cgi-bi...p?&I=LXJ759&P=0
OR
Should I use a Dumas dog bone universal … I’ll still need to shim the shaft
http://www2.towerhobbies.com/cgi-bi...p?&I=LXE444&P=0

3. I plan to run a solid shaft surface drive; can I use any of these (I’ve got these)
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXE472
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXE471
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXE470
http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXMNM5

4. How far aft of the transom should I place the prop; I’m thinking @ 2.5”

5. How much freeboard do you need to be safe? My float test, with gear, showed that I only had a 1/4” clearance at the stern. Maybe I need some smaller batteries.

Any comments or suggestions welcome

RE: Homebrew Mini V Hull with Outrunner
 

Images didn't upload ... I'll try again .... no luck I'm getting:

There was an error saving the file to disk.

RE: Homebrew Mini V Hull with Outrunner
 

Still doesn't work ... is it a Mac thing?

You can view the images here:

http://s183.photobucket.com/albums/x...nt=outline.jpg
http://s183.photobucket.com/albums/x...&current=3.jpg
http://s183.photobucket.com/albums/x...&current=2.jpg
http://s183.photobucket.com/albums/x...&current=1.jpg

RE: Homebrew Mini V Hull with Outrunner
 

that hull looks pretty good, one thing to make sure you do is leave a defineable sharp edge on all of the transitions on the bottom of the hull. whats it made of? sounds like it might be a bit on the heavy side with only 1/4" freeboard, you might want to rethink your hull construction method, or maybe switch to lipos.

RE: Homebrew Mini V Hull with Outrunner
 

Construction: 1/8 balsa framing 1/16 balsa sheet
Finish: 3oz glass cloth

RE: Homebrew Mini V Hull with Outrunner
 

anybody have any inputs for this guy? theres plenty of people out there with craploads more experience than me.........

RE: Homebrew Mini V Hull with Outrunner
 

I wish i could help him but im new here to boats myself! I dont know to much[:'(]

RE: Homebrew Mini V Hull with Outrunner
 

Hi I will take a stab at this
Use the dumas dogbone universal. Greatly reduces the alignment problems. Last I heard 3.2mm is the same as 1/8". You probably would be ok there.
None of the dumas props will work for your boat. Not if you want surface drive. A few Octura props could work here a X431 in plastic or the X427, X430, or X432 in metal.All of them are for a 1/8" shaft. The Graupner K series CF props would work really well here and don't cost too much. They would be 4mm threaded and would need a prop shaft with a 4mm thread on the end.
Your hull looks good .For strakes you could get some balsa or spruce square rods and sand one corner down to make a triangle . That would work. I have done that several times to make strakes. n.h.schmidt

RE: Homebrew Mini V Hull with Outrunner
 

lack of knowledge on my part.

RE: Homebrew Mini V Hull with Outrunner
 

Thanks guys,

I'ts a pity about the dumas props, I'm hoping the AquaCraft Nitro Hammer prop will work ... if not I'll have to order some Octuras.

I've got the motor and drive shaft mounted without a the universal ... it feels very smooth .... no binding that I can tell. I'll post some more pics soon ..... Hope to test run this weekend.

I think I'll run without strakes etc. first .. see how it goes.

Crash

PS: when mounting trim tabs should they placed flush with the bottom running surface or slightly higher? I think I've seen examples of both setups.

RE: Homebrew Mini V Hull with Outrunner
 

Lack of knowledge on my part.

RE: Homebrew Mini V Hull with Outrunner
 

Not to offend but the only two v hull plans I could find online were for the “Gas Mono”

http://new.intlwaters.com/FreePlans/gasmono.htm

and the Cobra.

http://jeanlouis.vivrat.free.fr/Cobra.PDF
http://jeanlouis.vivrat.free.fr/Cobra_P2.PDF
http://jeanlouis.vivrat.free.fr/CouplesAH.jpg

They don’t have strakes …. So as a newbie I figure some boats have ‘em and some don’t and if I can get away without the extra work well hey!

It’s not a matter of disregarding valuable advice I appreciate the input ….. Cheers

RE: Homebrew Mini V Hull with Outrunner
 

Hi me again,

Things have been a bit slow in the workshop ... but I'm getting there…

She’s pretty much sorted…. scratch built hardware, electrics, velcro batt. straps etc. all in place. I must admit that after reading about Proboat mini-v mods and MHZ Geckos this thing’s going to be a real snail.

Anyway, I’ll finish up and give her a go ….. But I’ve got some Octra x430 and x432’s on the way so I hope that will solve the surface drive issue.

In my quest to produce a homebrew quickie, I’ve already drawn some new plans and I’ve got my eyes on some Feigao 380’s or 540’s.

Anyway… here are some pics!

I've had no luck uploading images ..... any ideas .... they're jpg what's the prob .... mac?


http://s183.photobucket.com/albums/x...&current=c.jpg

http://s183.photobucket.com/albums/x...&current=b.jpg

http://s183.photobucket.com/albums/x...&current=a.jpg

RE: Homebrew Mini V Hull with Outrunner
 

Can you guys see the pics?

RE: Homebrew Mini V Hull with Outrunner
 

Yes they are very nice:D

RE: Homebrew Mini V Hull with Outrunner
 

So nice that I'll have to demand you to give it to me! :D I'm waiting to hear how it runs [8D]

RE: Homebrew Mini V Hull with Outrunner
 

Well I got her wet!

Took her to a little pond over the weekend … she planes! I was kind of shocked as she only has a 1000kv motor and sits real low at the stern. Speed wasn’t impressive but she was did manage to climb out of the water and throw a bit of spray … after a bit of cavitation … burble, burble.

I ran an unbalanced, kinda cleaned up Octura X432 and even after a few min at full throttle the motor wasn’t even warm.

I’m tempted to just wait for my new Feigao 380-14S 2820kv and strap it in, but there are some problems with the hull that I’d like to remedy. So Looks like I’ll go back to the building board.

Issues:

Like I said she sits real low in the water at the stern (about 1/4” clearance or less) As you can imagine it’s a bit scary when you drop of plane and watch this “big” wake catch up with the boat. I’ve already drawn plans for a boat with more freeboard, but I’m concerned about the amount of vee I’ve incorporated (currently 11 degrees: new 20 degrees) The ponds pretty protected so chop isn’t really an issue …. Flatter = faster?

The bow wave at half throttle is pretty impressive … viewed from the side, the wave is easily three times the height of the boat. Luckily, if you’re going in a straight line, the wave doesn’t fall on the deck. Once you get past 3/4 throttle the hull rises and the wave dissipates. I’m not sure how I’ll remedy this, ideally some chines …. But with the way I’m building these things, it might be easier to do a highish strake that reverses toward the bow.

The hull is very small and with balsa construction lots of space is lost to stringers etc. As things stand, I'm about a 1/4" away from achieving the suggested 33% balance point. I’m thinking I can increase the size of the boat a bit… an inch wider 2 inches longer… and still come in at a similar weight. Hey the battery pack accounts for 40% of the boat mass.

Here’s a question, how much should a boat like this weigh? With a 1100mah NiMH 2/3a pack mine comes in at 16oz.

Anyway, I’ll keep you posted