maverick4you

Hi to all you, I and my friend have bought a Hydro R8 boat, R.T.R. this is equipped with a 540 class motor and can run with 7.2 to 9.6 battery, the only info about the prop is a 40mm diameter, is there some body that have already modified this boat? We want change the motor with a class 600 about the prop i don't have experience about it.
thank to all for some suggest.
Bye Rocco Pietro & Roberto From Rome
(exscuse me for my bad english)
at this link some photo and two little films where tha boat run with a 7.2 battery:
http://www.piazzaletto-team.com/fotoboat1/page_01.htm

pompebled

Hi Rocco, Pietro & Roberto,

What a lovely place to run your boats!

Judging by the films, the boats hardly get on the plane and the sound of the motor is way to low pitched.

The 40mm prop is too large for a 540 in direct drive.

Changing it for a Graupner K-series 34,5 or 36mm will improve the performance.
That's where the problems start, as I think the 40mm is dogdrive and the small Graupner props are 4mm threaded.

Could you post a picture of the prop (on the boat)?

Running this boat with a 600 motor on 6 cells won't make much of a difference, the 600 motor will have more torque, but what you need is one or two extra cells (running on 7 or 8 cells), to wake this motor up.

I'll see if I can find the thread about modding this boat, if I do, I'll post it here

Regards, Jan.

maverick4you

Hi Jan, today i have add other two cells to the battery, now 8 elements, the photos that you have required i posted now.
Bye and thanks for all.....to the next time
ps we will buy the prop that you suggest.
Rocco

maverick4you

hi Jan , how are you? all ok? well... i have changed my old prop 40mm with a 37x1,4 graupner i have change the shaft too with a graupner m4, tomorrow we try the boat with this new configuaration, if we take photo or films a send you a message.
Bye, Rocco.
ps i will change tha 540 motor with a speed 600 7.2v graupner, know you how many ampere take this motor?

pompebled

Hi Rocco,

It's hard to say what the ampdraw will be, this depends on the boat set-up and propsize.

On our seven cell boats with surface piercing prop (36 0r 37,5K), the average ampdraw of the 8,4V 600 Race is 25 A with a 7-8 minute runtime.

As your boat has subsurface drive, be careful with a 37mm prop, in my experience it's too large and will fry the motor, no matter if it's a 540 or a 600 motor, check the temperature every two minutes, minimal!

If nothing gets too hot, run the boat with a full battery, flat out until the speed drops, measure the runtime.

Using the formula: 60 x battery capacity in A, devided by the runtime in minutes, you'll know the average ampdraw of your boat in that set-up.

If you take a look at the Graupner website (www.graupner.de) you can find data on all motors.

You can find a lot of info on how to make this hull really fast by going to www.rc-raceboats.de and use the search function ( "Suche" ) on "Trimmung", author: M3rl1n.
You'll find a long thread with a number of photos, showing how to go about it.
I added a few I have on my harddrive.

Regards, Jan.

Ron Olson

My Feedback: (1)

It's embarrassing when your English is better than those who have it as a native language and your spelling is much better.

pompebled

Sory, ill try less hart.

regart, jan.

Ron Olson

My Feedback: (1)

Hey pompebled, it wasn't pointed towards you, I can read yours with no trouble. We just have some that are U.S. citizens that I'm embarrassed for. You ought to see my postings before I hit the "OK", my spelling is fine, I have fat fingers so it seems. I just corrected this one 4 times already. Oops, five.

maverick4you

Hi Jan, i have read the post of Ron, if the problem is my english language i'm sorry i don't write any more.... bye

pompebled

Hi Rocco,

Your English is no problem to me or to Ron, just keep posting!

Ron was referring to people who speak English as their "mother language", as you've called it.

So, no stopping, just go for it!
If there's something, I don't understand I'll ask you to explain.

Regards, Jan.


P.S.:

In my post above I was just kidding with Ron, NOT making fun of you, no way, I would make fun of people with the intention to hurt their feelings.
My appologies if it felt that way to you.

maverick4you

Hi Jan & Ron, i misread Ron's message i think that there was problem with my english language, exscuse me.... i will continue to inform about the change on Hydro R8.
Yesterday i have make a new hole for the shaft... see photos.... i will order the new shaft and prop, for new prop i have select this cod of graupner 2327.39 series S prop, is ok for you?
Bye, Rocco.
ps: on photos there is always old prop too, i dismantle it when modified is ended
PS2 (not play-station2) i have post other photos and two little films of sunday 4 september, if you want you can see it at this link
http://www.piazzaletto-team.com/TDQ/page_01.htm

MikDee

Whats a Hydro R8 ???,,, and where can I get one, It looks like a renamed Kyosho Viper, A great little boat, once converted to surface drive, and all the hardware drag removed from the bottom.

maverick4you

hi, we have bought this boat in R.T.R. configuration offert, the boat is like a kyosho viper.
We are modifing the shaft architecture, we will remove the shaft from down site of the hull and put it in orizzontal position using an appropriate prop of graupner... if you see the photo that i posted is all most clear.... my english is very bad, sorry.
You can see the Hydro R8 at this site http://www.elleemmeshop.com/model2/m...modinamico.htm
bye Rocco
(Rome)

pompebled

Hi Rocco,

The distance from the transom (back of the boat) to the prop should be about 8% of the hull length.
In the pictures it looks too close to me.

The reason for this is that, once on the plane, there's a "dent" in the water behind the boat, if you position the prop in this dent, the prop will lose it's grip on the water and the boat will slow down.

For a 600 motor, a 39mm prop is too big, it will fry your motor.
On our seven cell monohulls with a 600 motor, we run a 36 or 37,5K prop.

What you need to do, is sharpen the transom, the rounded edges create a lot of drag you can do without...

Did you have a look at the German forum, I gave you the link to?
If you did, you'll know that a 600 motor is not going to be enough to make this hull fast...

The boat will steer better, if the rudder if positioned offset to the right, it will stand in the undisturbed flow.
Behind the prop you'll need a longer rudderblade (=more drag) to get the same rudder response.

Let me know if you need pictures or measurements.

Regards, Jan.

maverick4you

Hi Jan, my photos show only the prop not fixed, only for demostraction, i have take the photos and send it to my friend expert on hydro boat, he have say that the prop must stay at 5 cm from the back of the boat.... this evening we have had a problem... the shop of modellism called me for inform that the shaft and prop we need not are available![] i'm searching shaft e prop by another shop i believe to find all the material i need....[&o]
....Huston?! we have a problem! we don't have the need hardware to modify our boats!!!

I notice you asap if i find the hardware...

bye Jan.

pompebled

Hi Rocco,

You and your friends might consider to get a flexshaft with seperate rudder from Hopf in Germany.

www.hopf-modelltechnik.de

Take a look.

Let me know if you need help selecting or translating things.

Regards, Jan.

maverick4you

Thanks Jan, i'm seeking other shop in italy... preferibly in Rome for quickly resolve the problem...
know you if the site you gived maybe ship in italy?
Bye, to the next time..... che vita!

maverick4you

Hi Jan, how do you do? all ok ?
Last saturday we have put 12 cell in our Hydro R8, now with speed 600 8,4 motor and prop 37.5x1.4, the boat was very fast but after few minutes the electronic go out[].
We want change the original electronic with a good radiocontrol and a ESC, maybe a good choice the Jeti Navy 600?
This ESC can accept 8 to 30 cell and can use it with 600 and 700 motor, we don't want use other motors or brushless motors.
I wait your precious reply.

Thanks and bye bye, Rocco.

pompebled

Hi Rocco,

Did your motor survive the 12 cell adventure?

When you run a big hull like yours on 12 cells, you need a 700 motor, or you will keep burning things up.

The Jeti 600 Navy is a good ESC, I don't know how much it costs in Italy.

You could also check out www.cti-aichtal.de and see how much the MIMIR esc would cost you, this 30V-50A should work fine in your set-up. (if I'm not mistaken 34,50 Euro's ex. shipping, order for your friends aswell, lower the shipping costs)
We (my son and I) run four or five of these ESC's in our various 12-14 cell boats, no problem.
I made them watercooled, as a precausion, but this is not really necessary.

Helmut Marchall from CTI is a nice guy, mail him and ask what his advice is.
The CTI service is excellent, if a ESC should fail (shi..happens), mail CTI, send it back and receive a new one, no questions asked.

Regards, Jan.

maverick4you

Hi Jan you are a friend, thanks for the fast reply.
In italy we buy the Navy Esc at 57,00 euro.
Good the joke on " 12 cell adventure for speed 600" this is like a film " The Speed 600 and 12 cell.... will remain one only!"
Our 600 8.4 can run max 16 volts, the next step maybe the speed 700.

I notice you about the next result....

Bye Rocco.

maverick4you

Hi Jan, i post some photo about the modify of my Hydro R8, i believe to have some good results...
next sunday, if don't rain, i will go to lake to test the new configuration... bye.
Rocco

pompebled

Hi Rocco,

Nice work on the modifications!
I'm impressed!

Please give some details: what motor, how many cells, what prop?

And please, post a picture showing the boat from the side, so I can see what angle the propshaft makes in relation to the keelline.

I can imagine you're exited to get her on the water..

Regards, Jan.

maverick4you

Hi Jan, well, the motor is a Graupner 600 speed 8.4 volt powered with 12 cells (if survive..) the prop is a Graupner 2318 40.5x1.4
the e s c is a Jeti navy 600.
Yes, i'm very impatient to put in the water...

Little thing off of this discussion:
Last week a friends, that work at our marine engine division, have gif to me a poster with a true Hydro powered with two Caterpillar's Diesel Engine, is fantastic!!!
Bye, Rocco.

pompebled

Rocco,

Watch the heat build-up with that 40,5mm prop, if you have one, start with a 2318 37,5K.

It might be wise to change the Tamiya connectors to goldplated bullit style ones, or Deans, before the 25 A average wll fuse them.

Regards, Jan.

BTW: nice poster!

maverick4you

Hi Jan, thanks for your suggest i will change the connector ASAP, our dealer not have other prop i will try the model with the 2318 graupner size 40.5x1.4 i will search other dealer for change the prop too.
What do you this about the graupner prop S series with?

bye Rocco