bebopin64

My Feedback: (2)

the only answer is twin jet drives. it would scream.

SJN

They are in series
6 cells on the 9,6V sp 700 hardly turns the motor.

I think better batts. wil help some

The prop is only about 8mm (0,31" ) from the bottom of the hull. I was scared it would cavitate agin like the other motor.
I found a picture of the Graupner Taifun which uses the same prop and shaft, and eyerballed it form the pic


Thanks for the tips. Still got the filling/painting to do at least.....

SJN

hehe....maybe in another lighter hull....... it weighs 1850g (65.2 ounc) without batteries

Not the lightest

bebopin64

My Feedback: (2)

dats pretty heavy

Crabstick

Hi Sonnich,

Does the hydro stay on the plane when turning ? what speed controller are you using ?

Matt

SJN

I have only done soft turns at speed with it, and it does not slow dwon.

Im using a schulze 50 amp speed controle for an airplane.

Crabstick

generally with a hydro, the prop will cavitate at first quite a bit before biting and jumping up out of the water

http://www.drcwebservices.com/ffe/hardware.htm

have a look at the hydro hardware here, will give you an idea of what the strut angle is and you can move the prop out from the back of the boat so it wont touch on the transom, also have a bit of a read on Surface Drives.... it will help you understand how they work which also helps in the setup, the basic principle is only one blade of the prop is in the water at once, which allows for a much larger, higher RPM prop, with reduced drag because none of the hardware hangs down below the boat causing drag

SJN

Im looking forward to seeing you Hydro being built.....and your friends.
When do you think yours will be ready ?


With the other motor, I applied throttle slowly, and it began to pick up a little speed, but then suddanly, you could hear the water cavitate, and it almost came to a dead stop in the water.

SJN

Ill try some different prop sizes.

A little vid from today: http://www.putfile.com/media.php?n=NQD2

hellomynameisdookie

Looks like a lot of fun!

What motor is in it now, and on how many cells? What prop?

SJN

Its a graupner speed 700 Neodym 9,6V
12 cells
40mm prop included in the graupner Hydro drive set in the previous pictures

hellomynameisdookie

It looks like it's running pretty good! I bet it's a lot more fun now than before.
If you want some more speed out of it, try stepping up the prop to a 42mm and see how she runs. That 700 can handle a 42 no problem.

SJN

Its WAY more fun than stock.......stock was just walking pace.

The temp. of the 700 is hot with no cooling at the moment, but it can certinly take more abuse.

Maybe I should find another motor mount that would alow a cooling coil around the motor.....its not nescesary as it is now.

I think ill make a duct from the huge air intake, and lead it down to the motor. That should help a little too

Got to get some more props next week.

Crabstick

here is the progress i have made, i hope to have it ready to run tonight

http://noonhost.com/mmpbc-about2.html

SJN

Looks very nice !
I cant wait to hear the results.

properchopper

Hi Sonnich,

Here's some pix of the scoop & cooling duct I put on my Twinstorm. These really help & it's a natural concept to take advantage of all that cool air passing over the boat !

Tony

ps; hope my photo upload worked

SJN

Looks good Tony.....might as well use all the cooling you can get

Crabstick

Hi Sonnich

first test wasnt very good, pushed a lot of water and didnt get onto plane, i was going to try an 8 cell pack but the receiver got wet so thats on hold for now although i dont think i will bother with the 540 anymore i will just put the 700 neo 9.6 in tonight and 12 cells will also be going in

Matt

SJN

Sorry to hear that.........

I have been thinking a little about mine, and what everybodey has mentioned.......

My CG is too far back, and I cant realt see how I could move it further forward. Also, I have to raise the prop a bit, and I think ill try that next. But there may be no point in doing that, if the CG isn`t correct []

SJN

To acheive the correct CG at 5-6cm instead of the 10-11cm now, the batteries have to be moved here:

SJN

ok, I can solve the CG issue a little easier........if I can do this:


I can move the engine and batteries forward about an inch or 3 cm, but because the prop shaft isn`t longer, the prop would also be moved 3cm further under the boat towards the front.
Is this a bad location for the propellor?
Will this effekt performance ?


I can also move the engine 3 cm`s back, and place the batteries infront of the motor.
This would make the prop stick out about 3 cm`s behind the boat, and the steering fin would have to be moved to one of the sides.


What do you think about these idea`s ?

SJN

ok.....now in the mix of plan E

One cool thing about buying a crappy bout, is you learn a heck of a lot rectifying the problems
So far, thanks for all the advise...I still hope to improve this boat.


I have moved the batteries into the nose section, and the motor aft. I have also raised the propshaft.....letts see how this works :-)
CG is MUCH better now than before.

gulfstreamI

I think you're on the right track with the mods for your hydro.

My Kyosho E.P. Hydrojet has a similar set up for higher speeds

Crabstick

Hi Sonnich well its been a lot of trial an error but i finally got mine to plane, one battery in the nose, and one beside the engine, i have my prop angle completely flat now, and also a ride plate on stuffing tube and i have modified the rear ride surfaces - ill post up pictures when i get home from work. My boat will not get onto a plane by itself and i have to throw launch it at the moment, then it actually quite fast!! ... because of your prop angle you have plenty of lift to get the rear out of the water, but it will cost you top speed. mine i am relying on the air and hydro lift from the hull to get the boat up out of the water

the rear wings are what is keeping the back of the boat under from breaking out onto a plane, thus i am going to chop the buggers off tonight, test run in the morning.

Matt

SJN

Looking forward to the pictues Matt.


I tried my new setup today. Im not too pleased with it.
I think it is working as it should.

The prop cavitates in the beginning, but when you advance the trhottle slowly, it comes up to speed, and planes. But as it is more nose heavy now, I can see the front pontoons are deeper in the water now, and creating more drag.
I can hear that the engine has alot more rpm when planing now, but I think it needs some more water to make this barge go

It is only slightly faster that the previos setup when the batt packs are fully charged.
When the peak charge has ben used in the packs, the boat slows a bit, and drag from the front realy slows it down alot.


I dont know what to try now......I think ill go back to the previos setup as the boat performs smoother through the whole battery pack span.

Also, because of the offset rudder, it now veers to the right the faster it goes, requireing trim.