Quicksilver1

good question, in my experience with full size boats, it usually happens when the drive is trimmed up and theres too much weight up front. I would try moving the center of balance aft, if that doesnt work try moving it forward, if that doesnt work.........trim tabs. And by changing the balance I'm referring to moving the batteries forward or aft.

btw, the jet-villain is going to stay a jet villain, but it'll be a month or so before it's rebuilt and the new villain WILL have a surface drive. I've made my decision. It'll be neat to have two working villains.

dirtysouth31

i got a question? what about putting a jet drive in an outrigger?has it been tried or can it be done at all?doesnt seem like it would work.

headhunter23

Why wouldn't it work? Would prolly work pretty good, except if one pontoon is up high other down low etc... as going through rapids.

Hey quicksilver I moved all the stuff right to the front of the boat. The nose was almost submerged and the rear was out of the water so much that the jet couldn't start unless I forced the rear under the water to get it going. This corrected some of the porpoising until I hit 2/3 then it just came back.

Idea's to fix this? I would like to use trim tabs as a last resort, should I pull out the drive and cut more off the hull? It seems that the front is too buoyant, and maybe reset the drive so the jet is shooting lower(right) to get the hull down?


Oh yea... If I did go the trim tab route, where to stick... outter edge, middle close to centre?

Quicksilver1

I think you should mod the hull, or buy a different one, from the pics(thx for the pics btw), it looks like the mid section is way to deep, kind of like a whale shape. Getting rid of that would be tough, but it can be done with a cutting wheel and fiberglass. I think this hump is causing the problem you could try trimming the boat up. jet boat like a constant dead rise, that's a big reason I keep sticking with villains.
To fix it without major surgery, tabs could work, I would put them maybe a 1/2" from the centerline, I would try trimming the bow up and try the batteries all the way back one more then, it's a matter of fine tuning it. tabs maybe Aft I took off my trim tabs on the villain, it chine walked wildly at WOT.

here's a picture representation

DRAGONFIRE81M

I to have the same problem with hopping i can only go about 5/8 to 3/4 trottle on the mini- v hull . it has gotten a little better after flating the bottom out .

headhunter23

I think I will do the mid section mod first. Essentially tape the whole hull down evenly to a block then either have a friend with a bandsaw saw it slice it evenly or make up something here that can cut it evenly or atleat beable to check as I grind away. I have 2 weeks till batterys come anyways. Thanks for the suggestions... was thinking the same last night when I slept on it.

Dragonfire I thought you were going to trim more hull away...

Btw this is an edit to the post. Just a couple more questions to clear up before I start cutting. First the jet drive doesn't seem to sit flush on the bottom. Is there a way ... kinda difficult to get across but should the grills be pararell to the hull? Or should they be angled up a bit at the front for better suction which would then have the jet trimmed down (uh shooting lower, to get more hull into the water). Any other ideas suggestions would be appreciated.

Ivan.

DRAGONFIRE81M

Yeah i cut a lot i edit your pic to show how much i cut out . i dont have a pic of it yet but ill get one on tonight . i used a cutting wheel after drawing the cut lines on the hull. and used a sheet of alum to fill in the gapping hole and glassed it over i even bent the sheet in to a arc or channel to force the water in the inlet. you already have some downwared angel on the nossel becouse on the angel on the transom

DRAGONFIRE81M

sorry forgot the pic

headhunter23

So you think the angle of the jet drive is ok? Just leave it? I would have to cut right to the last horizontal line at the top to make it flat with the drive.

DRAGONFIRE81M

thats pretty much what did . ill show a pic of mine . after i take my son to karate .

DRAGONFIRE81M

here u go

Quicksilver1

I just got home so I have to take all this in, but didnt want you to think I was ignoring you

headhunter23

So dragonfire are you trimming more then? I notice the lines are going further than what you've cut.

I've already torn my hull all apart and all the fibre glass out, I've cut so far as specified on my photos, still contemplating wether to pull the drive and reposition it so it shoots higher out the back, if just a degree or 2. Will cut the aluminum skid plate tomorrow and glass it in, more than likely make the steering stationary, pop the motor back in and test quickly on the pond. This would entail drivin it till it hits land but should beable to determine quickly wether either more cutting will be required or to pull jet drive and change the degree.

Pita to figure this out... oh yea this should be helpful for the thread.

Look near the bottom of this page, you'll see the bottom of a decent jet drive boat.
http://www.naviaboats.com/frame.php

DRAGONFIRE81M

to be hounest if i ever got the time i would mount the drive parrelle to the hull and glass the outlet to the transom to get a streat thrust . and i wont to put in a light waght bl motor i have a 45 amp esc i would love to see some closeups on how you mounted that outrunner to the drive

DRAGONFIRE81M

thats looks great is that hull glass or abs if its abs i molded mine with a hair dryer and shaped the abs

headhunter23

Good call on the molding idea.. will have to find hair dryer, I think I have a paint stripper heat gun somewhere. The hull is abs, had lined the inner with fibre glass after seeing quicksilvers hull that looked like it was through hell and back. I was thinking it could be possible to make one long strip of aluminum like quicksilver and mount the jet drive directly to it then mount the whole thing and plug to transom.

There's only one thing wrong with the idea, it would require the aluminum strip to be wider than if I do it the way I am now. Because it would have to go completely around the drive and I'm sure I would want a few (3mm) thickness on the edges. The mounting of the motor is just a strip of aluminum with the holes in almost the right location. Done by hand and drill press, really really need a clamp for the drill press. Verner (measuring tool) is invaluable for this stuff, 7 bucks at princess auto.

Ivan.

Oh for images for mounting bracket... A quick way that I made this...

Get strip of aluminum (mines 1" wide a meter long, do all the drilling before you cut your bracket off the main piece)
Drill main hole, ie find drill bit as large as needed for motor, then get verner, measure the mounting holes for motor. Drill on both sides of main hole in aluminum.
Then test, if it works great, then continue to step three, other wise start drilling process again a little down strip.
measure mounting holes for jet drive.
use verner to scratch where holes should be. (oh yea you want to start the hole so the drill bit knows where to go, get a hammer and a punch, I used a screw, works just as well)
drill holes, I drilled mine the same size as the screws and ran the 2.6mm screws in and out a few times to create threads (love aluminum just wish I could weld it)
after everything seems to work out, cut the plate from the rest of the aluminum.

mount motor to plate, mount plate to drive.

Also just a note, the motor shaft was way to small, I think it was 3mm or smaller, luckly I had some hobby aluminum that was 3.2 outdiameter and the inner diameter just fit over the shaft. used dremel to make indent for set screw, cut alumium by laying it on the ground and getting a box cutter blade and rolling the aluminum tubing back and forth on the blade where I wanted it cut. You can get surprisingly accurate for cutting aluminum tubing this way, just check to see if it needs to get cleaned up at all. pop on shaft, tighen.

Also I gotta say this shaft for the mini jet is a little f'd up because the set point on the prop shaft is way too far forward. Actually I noticed a few things they could certainly improve on this drive. LIKE THE WASHER THAT SITS BEHIND THE PROP AND INFRONT OF THE MAIN THRUST AREA, WHY IS THE WASHER SO BIG!?[:@]

DRAGONFIRE81M

What kv is the motor your going to use. i would like to know how hot it gets after a good run ? i have a 6600 kv 1/18 motor and the shaft size is 2mm i have a grumpner u joint just like the one that comes with the drive that fits that motor when i was going to put the bl in the stock mini-v i was talking about the outrunner motor not the inrunner . did you use this bracket?

DRAGONFIRE81M

here that u-joint i used GR355 2mm to 3mm Universal Joint ..... $ 9.70
IN STOCK

headhunter23

oh the outrunner... that was easy, just drilled three holes in the jet drive mount where I wanted the screws in, made the holes the same size as the screws and just screwed them directly in, had enuff bite.

This was done in the boat so the holes were off, used a 20cm long flexible drill bit.

Your using a 6600? Geez a bit overboard? If these drives are similar to the kehrer drives, the jet would run on 15000-20000 loaded. I'm now going to use a 3200rpm/kv 25 amp (the red motor in the pics) at 7.4v, I bought another 11.1 to replace the lipo I messed just to see if I can get the boat to run at that speed without the porpoising.

just rough calc, 7.4X3200= 236800 * .80 (rough of rpm underload and running at motor efficiency) equals 18944 so I am in that zone.

at the 11.1X3200 = 35520 unloaded * .80 =28416 loaded optimum running

So on the 11.1 I should be running hotter because it will be pulling more amps to try and get the motor to the running speed (these are all rough, im sure someone else can get these numbers a little better).

Not sure on heat yet as I haven't run the 3200 on the single 11.1 lipo long enuff because it runs at 12 amps constant and bursts to 20, and because the esc is set for 25 and prolly bursts higher I only did very short runs and very gradual build up. When other comes will let ya know. I would like to try no cooling to see if at 7.4v the motor is ok, for the times I did use it, I actually noticed no heat build up at all, infact the motor was cold.

Here's short vid I took yesterday to see power of 3200 on 11.1v http://www.youtube.com/watch?v=CG8XScOJ4CA, way quicker.


Also as a note, the 1600rpm/v outrunner running on 10 amps, I could feel heat building up for the same run time, but not overly hot, just noticed it was heating up.

The point where it stops the shaft from turning is for cooling?? I gotta get my german up, these plans are a pita to read.

DRAGONFIRE81M

ok this is hard to explain first you know where the reverse flap mounts to the nossil you drill the center of the pin in to the pump just in front of the impeller . drill on the red line you can do this on eather side

headhunter23

Yea I got it after looking at your other photos... does the bucket work if you do this? I would assume not. So really these weren't designed for cooling right? But work just as well?

DRAGONFIRE81M

you can still use the reverse youll need to press in a pease of brass in the hole you drill to move the tubeing i plain on doing this just havent and i dont intend on useing it anyway . ill see what size bit i used tomarrow . yes its not inteded to be used as cooling but it scurts out a stream 4-5 " long after going threw the motor coil . and 6-8" just in and out

headhunter23

Coool So cooling isn't an issue! Sweet. I still hate making the cooling coils around the motor though.

Quicksilver1

your boat looks familiar now

DRAGONFIRE81M

this is going to be the new home of the jet drives thats in big blue . its a 22" deep v on ebay . any idea about big blue i thank i mite go prop and bl