DRAGONFIRE81M

are you full trottle on that run .thats like 35000 rpm

headhunter23

Motor is still cold under that one run, just not out long enough to heat it up. 11.1v X3200 rpm =35520 less 20% for load, so 28416 rpm. But I'm sure it's running lower rpm due to jet drives seeming to max out around 20 000 rpm.

Really wish graupner had numbers posted and testing done other than saying uhh 500-600 brushed... what kind of data is that?

Oh yea that was full throttle.

Ivan.

DRAGONFIRE81M

your not telling me nothing there im asking all this becouse im not sure if ill put bl in big blue or rip the drives out and put them in a 22" hull thats on ebay. it seems that 25a motor works fine so ill go with 30a on blue and im going with a 40a esc and the ammo 28-35-2700 in the mini-v i dont need the rpm on that boat just less wight.

headhunter23

What's "bl'? And what didn't i answer? Ya know what drives me crazy? How there is such a wide range of motors, rpms etc and no general guidelines. If I were putting a motor in the 22 or larger, I would try to have the rpm/v around 2000 or under, the smaller boats seem to beable to handle 3000 to 3500 just due to the lower weight and normally smaller props.

Personally I wouldn't put the mini-jet in anything bigger than 22", i would get 28mm or 29mm jet for the larger size. But this is all general guesses from threads and personal experience, seems someone needs to be guinea pig for every combo.

Ivan.

DRAGONFIRE81M

bl mines brushless. i sow acouple people on here useing it so it kinda stuck . ill try to get some vid of my big blue 31" deep v with two mini jets and two 15t brushed motors on 7.2v youll see i really dont think im anywhere near the rpm range it needs to be in . the mini-v if you have seen the vid on it . has perfict rpm for its size . its just to top heavy becouse of the 550 12t motor im running in it . its fine on 2s but when i put 3s in it . it wil flip 180 bearle rolls

headhunter23

I actually had a very small bit of the rotation that you were talking about. I think its from the torque more than anything. When I gunned it, the one time the boat went 1/4 over to one side on a straight away, kinda neat, I don't see it spinning right over like you had said in a previous post.

Personally if I were to rebuild this exact same boat I would get the same motor, just a higher rpm/v and run at 2s lipo's. I would say 3500-3600 and I bet it would be the same speed as it is on 3s just a better setup and hopefully more efficient at max speed. I like your setup on the mini-v, the whole vid and everything made me try this setup, just because I wanted a small boat that I could leave in the truck and run streams that I come across. Plus I think i will put in a wireless fish finder transducer in this boat too just because it would be great to throw in pack and check out spots on the fly.

Ivan.

MORE SPEED

Can I ask you how much this project has cost?

MORE SPEED

Quicksilver1

purely comparing it to a normally propelled boat, it doesnt really cost anything. My jet-Villain cost me just as much as my current build, the 700 powered surface drive villain. Jet drives are cheap, setting them up has proven to cost more........emotionally at least.

DRAGONFIRE81M

yeah they are alot cheaper your looking at $40-80 for a grupner drive . thats your drive line prop and steering system all for one $ you could spend 40-80 just on one peace of a prop driven boat

headhunter23

12.5" hull from bbyracing $20 bucks plus shipping $20 plus F$&ing bs brokerage fees $13.26
Gruapner mini jet $35 I think, plus another 15 shipping, plus 13 for damn brokerage fees
radio reciever all that already had
lipos were 25 bucks for 11.1 at 1200mah with 5 dollars shipping from hong kong no brokerage fees.
Steering cables etc 5-8 bucks
steering clamps 5 bucks
Motor 22 bucks plus 5 bucks shipping from hong kong
esc 25 amp i think was 15 bucks plus 5 bucks shipping.



so total less radio receiver and servo $239, wow those shipping charges really rack up. anyways yea was expensive but unique fast fun and i love the size.

If I lived in the states or we didn't have such a retarded shipping system between the two countries it would of been a lot cheaper.

Ivan.

joccee

I think my jetsprint is about 280$ with shipping. And the stuff I got for that money was hull and jet, 60A esc, feigao 380 9XL, 2x 1600mah 11.1v lipos, 10 deanstyle conectors, 10 3.5mm goldplugs and a cable for connecting 2 batterypacks in paralell to the esc.

but thats a pretty expensive hull if you compare to the micro patriot (jetsprint+jet-135$, micro patriot+jet-55$)

DRAGONFIRE81M

mini-v $79, jetdrive $34, sec rx $49 servo $15. had the motor,esc,tx,batterys around $177 + tax no shipping got to love liveing 35mins from hobby lobby . it would have been cheaper if i had just got a bear hull for $25 but im putting in bl so add $22 for a bl esc 40a and an ammo motor $ 32 so $231

headhunter23

Well lucky me, batteries and new esc made it. Will be cutting her all apart again to make her stronger, faster and more aggressive. Will update pics tonight depending on progress.

Ivan.

headhunter23

Well it's been a while. Boat is actually done and running. Essentially got caught up on a bunch of stuff, for example the screws for the steering weren't stainless and were rusting, along with the motor mount stuff and the steering rods themselves. Converted all, and changed rods to brass, so no more rust. Bellow is all the photos of the progress. I had converted the esc to one with forward and reverse, which works fine as long as the batteries are all the way in the back of the boat allowing the jet to be fully submerged, but then that changes the way the boat runs, ie skipping across the water. Another issue I noticed when I rebuilt is chine walking, for those of you that aren't familiar as I was, it is an imbalance or poor hull that allows the boat to sway left and right. This can be helped with tabs but I didn't have any luck through that solution. I might try strakes along the bottom or whatever ya call em later. I was able to reduce the chine walking by rebalancing the weight, essentially I had to move the reciever up to the front centreline and also add some pennies to the left side of the boat to balance out the extra weight on the right from the cooling coilsl. Also to improve cooling, essentially to add cooling to the ESC I actually put the back right on the coils. I like the look of it, sprayed everything with silicon so i can run the thing filled with water except for the receiver, which I think I will put in a balloon.

The antenna kinda worked out the way it is due to moving the receiver to the front, but I still had the hole in the back. Popped the other end in, voila no holes. On top of that it's actually great in that it works like a plug so if I have water in it, tip back and pull antenna out. I've already used it once like that. But for some of the stream stuff I can see it being a pita because of going under logs.

Right now I'm pretty much running 2s lipos, it actually isn't neccessary for the increased speed from the 3s lipo because in the stream it just hops so much just by the rapids themselves that more power just means pumping water to pumping air and back. Which actually doesn't increase the speed anyways.

The boat handles not bad in the rapids but it does have a tendency to dive under. If the nose gets caught for any reason, for example going over a rapid then points the boat down, she'll submarine. I actually submarined it a few times, the first few freaked me out but am now much more comfortable with it. I actually had it caught 3 times for 3-5+ seconds underwater, once I thought it was just stuck tumbling in this one rapid, and it just wasn't coming out, so I gunned it and it popped out 4 feet down stream from where she went under. I gotta say this has been a fun project and I'm happy with the outcome but I think I will be changing the hull to try and correct some of the issues that I've been having. Anyways have fun looking at pics and videos.

headhunter23

Whoops more fotos!

headhunter23

Final photo and videos...

First river run, missing the better rapids but wasn't possible to video and use camera at same time. Plus lost light really quick.


first run http://www.youtube.com/watch?v=9z_3H1SNyMo


Second run


Missed you tube second run first video attempt http://www.youtube.com/watch?v=T8WOhJHkE0M
first vid http://www.youtube.com/watch?v=N3k3lXLFQGM
second vid with flipover at end http://www.youtube.com/watch?v=MIrSgZC0Q_0
third vid http://www.youtube.com/watch?v=ae7NryACEvQ
final http://www.youtube.com/watch?v=U1ZV1kn9lRc

The last two videos you can really see the diving I was talking about, will have better ones once I get a video man out, can drive much better.

Ivan.

headhunter23

Well this is a little different than last post. [:@] I decided to rip the boat apart yet again, the reason was I wasn't happy with the performance. At speed, it would hop, I can correct it with a tab out the back, the other I could improve but never eliminated the chine walking or left and right at speed which made it unstable and unable to turn. Also dragonfire had mentioned that the boat appeared to be overweight, a buddy who's been following it agreed, and after using the mini jet to fish out my hammer (what's with the rubber between the couplers, like who's the fricken genius that decided to put such a weak link and ship em with the kehrer jet drive (hammer too!)) I noticed that at slow speeds she really was pushing too much water. So what to do? Rebuild again! But stronger, faster and more aggressive!

So got a bunch of photos for ya guys, essentially the first is before she's torn apart. I noticed in photoshop that the aluminum plate I had made earlier didn't seem to be straight in the way it was layed. It was close but still off. So decided to remedy this with better planning. I also decided to add fins to the bottom, the one thing I wished I did now was to make them more flat for a bit, instead of what they are, fins. I foresee it possibly getting caught up on stuff a little more but also this should help the chine walking. So took a 1" square tubing did a bunch of measurements and found that the jet drive would fit just inside. Amazing luck.

Anyways cut the plate, and ground out the holes and plate, fins etc. Took hours, broke it up to 2 days. After very very careful grinding managed to get it to fit in the plate. Another thing with rebuilding again, the transom was getting chewed to hell because of the adjusting the jet up and down to try and correct the porpoising. So cut it out and replaced it with aluminum. I don't know how these machine shop guys line up the screw holes but I only lucked out in getting 2 correct. So will have to mess with the drive to get the other 2 to work still. Both plates and drive will be glued together. Ummmm... what else, oh yea the grate. When I was driving the boat in this one river I managed to bash one side of the grate and it pulled out of the one side. Decided to correct this deficiency in design by putting carbon fiber rods in, same size as original but had to dremel out he holes so it poked all the way through etc.

Anyways that's about where I am. My buddy is coming sunday so need to get it done by then.

Oh yea a few other things, flipping back to outrunner, but running it at 14.8v, screw the cooling. This was the original motor, never really got hot running the boat, hope it stays that way because theres not really an effective way of cooling except putting a small prop on the motor to function as a fan (which I have and will use if neccessary). Doing this alone will save me 50-80 grams I'm betting (electric scale is on way care of ebay, which I would be using for making jerky, mmmm...) because no more cooling, copper, water, tubing ESC, etc. Also I'm going to try and get rid of the screws for the servo and steering and reduce the 2 rods to one, put the servo right at the back but haven't quite figured this out yet. So overall hoping to shed atleast 100 grams (oh less glue this time too).

Well take a look at photos... more on way plus hopefully video of running on sunday.

headhunter23

More...

headhunter23

Whew that's it for now.

alloutcustom

very nice. i know its tempting but try not to tear this one apart too

headhunter23

Well if it works the way i want it too, neither of us will have a problem with eachother.

DRAGONFIRE81M

[X(] that looks sweet love the alum and i thank the inlet skirts will work great for the 180 and the kick out behind the outlet will act like a trim tab. looking good cant wait to see some vid

headhunter23

Yea, it's actually a combo of your idea and quicksilvers plate that was on his old villian jet drive.

wave waker

hey headhunter23,,that's really impressive project...i like the videos man!! keep posting more,,hope u can get a camera man for a close up shot in action[sm=thumbup.gif]..keep it up..

headhunter23

Yea got it done today, a couple minor things but one new problem from the fins, it grabs like hell on rocks, going to try smoothing it out and such wax it etc, because previously it would just skim across them with just the plate. Little frustrated, will update with photos and videos in a bit. Funny but crappy at the same time and seems to happen often, got screwed by the set screw. And didn't bring any allen keys when I went out, so it was litterly a 6 min run of getting half stuck on rocks.

Ivan.