Epr 5000

[pda75]

Hi

I have started a new rigger and here are some picture of the build.

It a 1,28 meter (~50 inch) long rigger about 16 lbz. It will be powered with a lehner 3040/12 (875 kv) with lipo 10S2P. ESC is an YGE200 Navy.

EPR 5000 means in french "nuclear plant 5000" and in english "Electric Propulsion Rigger 5000 watt"

the boat is design for oval racing with 90 nitro riggers.

CDG is of course a real question. The implementation in the following:


2 lipos in front, the motor and 2 lipos in the back. The weight on the strut could be in a range of 700 gr to 1,2 kg (eg 0,9 lbz to 2,1 lbz).

My calculation based on rpm and propeller size (likely to be an octura X460) is that the right position of the CDG is obtained with a weight of 1,5 lbz on the strut.

The flex wire is about 60 cm long: Rember the the motor can move backward and forward in order to cope with flex wire length reduction. I hope that it will work well and that the flex will not blow up.



Feel free to help me as I have not found many similar projects

regards

Pierre

[pda75]

Here is the engine : it can move forward and backward in order to avoid flex cable reduction

[pda75]

For fun, the sponson compared to mono 2 (70 cm ~ 27 inch) electric boat

[pda75]

Water proofing of the hull is ok.

My assistant is checking that no water is coming !

[pda75]

the painting

[pda75]

the boat first run was this summer. Speed is fine. it runs about 110 - 120 km/h (eg 70 - 75 mph).

Some video :
http://www.youtube.com/watch?v=C32EwV5K4a0&feature=related
http://www.youtube.com/user/scyllias91#p/a/u/2/C32EwV5K4a0

The elogger (from eagle tree) is not working in this hull. it's to close from the motor and RFI from the motor reset the logger : I need to change all the wires.

I will also make some changes to put more weight on the strut in order to use bigger prop and hopefully go faster. Weight on the strut is currently about 1,1 kg (39 oz) and I need 1,4 (45 oz).

I am now starting the winter work :

1-new transmission with teflon instead of brass tube and oil. (too much noise and vibration)
2-More weight on the strut
3-improving the e-logger (eagle tree) system.

regards

Pierre

[carlcisneros]

Pierre:

what is the angle on the strut?
It looks like it has too much angle,

Carl

[pda75]

Carl,

I have tried various angles. Even with zero, the strut is "bumping" like on one of the video.

Pierre

[carlcisneros]

what prop are you running?

Carl

[pda75]

Hi

I have tried a couple : X460; X560; Y557, V955, 1657 and 1457. So far the X4 xx et Y5xx series working well.

The 14xx, 16xx provide too much lift (or I need to put more weight on the strut - that's the winter work)

I should get some propshop prop soon.

Regards

Pierre

[carlcisneros]

good choices on props.
what you can do for adding weight to the back end, is get a 2 to 4 ounce (up to 250ml)
fuel tank and put it in the back of the boat and add water to it until the back end settles down to your liking THEN put that amount of actual weight back there.

Carl

[pda75]

good choices on props.
what you can do for adding weight to the back end, is get a 2 to 4 ounce (up to 250ml)
fuel tank and put it in the back of the boat and add water to it until the back end settles down to your liking THEN put that amount of actual weight back there.

Carl

We had the same idea. :banana::iagree:
I did it and came to the conclusion that I need about 150 gr more.

I will have to make some changes (nexw antena mount, new servo moint, some pieces of carbon to remove etc... ) in order to push backward the lipos pack and stop running with a water tank on the back. : that's the winter work.

Pierre

[karolpenconek]

Hello. Really nice hydro :olleyes: Did you buy it or make it yourself?

Thanks Karol, Poland

[pda75]

It is home made : We are three friends working on it : one for the hull, one for the painting and myself to coordinate and assembly.

Pierre

[pda75]

A new motor mount
http://www.offshore-rc.com/forum/uploads/post-246-0-04510800-1297608538_thumb.jpg
http://www.offshore-rc.com/forum/uploads/post-246-0-79677200-1297608544_thumb.jpg
http://www.offshore-rc.com/forum/uploads/post-246-0-29866000-1297608585_thumb.jpg

Regards

Pierre

[Brushless55]

any updates on this sweet ride!

[pda75]

Some video from last fall. Since I have upgraded the transmission with teflon and an oil tank.

the fall run
http://www.dailymotion.com/video/xieay5_epr-5000-17-octobre-2010-daumesnil-1-2_sport

The oil circuit in duty (see the bubbles). An oil pickup in the strut and the oil goes back to the front of the teflon tube
http://www.dailymotion.com/video/xi0acy_mvi-0553_sport

[Boaterguy]

I think the prop is running a bit low, try raising it a little bit (remember, as little as possible, don't want to break a prop or over-rpm anything) that thing is sexy though

[pda75]

You' re right. That's the next step.

Pierre

[pda75]

I have create an oil tanker : there is an oil pick up in the strut. The oil goes back to the front of the tube, just with the pressure.

I have made some oil pressure measurement,by measuring how high the oil goes in a pipe when getting out of the strut : At 30 000 rpm, 1,4 meter, eg a pressure of 0,13 bars, e.g. 15 PSI

Regards

Pierre

[pda75]

60665

60666

60667

60668

Some more pictures running on water in my gallery
http://forums.offshoreelectrics.com/album.php?albumid=344

[pda75]

I am wondering what prop should be the next one.

The set up is 10S2P lipo
motor : Lehner 3040/12 (Kv = 875)
Esc: YGE 200 Navy

With an octura Y557, it runs at 130 km/h (81 mph)
With a propshop 6017/2, it runs at 133 kmh (83 mph)
With an octura X460, it runs at 124 km/h (77 mph)

According to the e-logger from eagle tree, the rotation speed is about 30 000 rpm at full speed.

Which prop would you suggest ?

Regards

Pierre

[Boaterguy]

depending on temps maybe trying an octura 655 or 657, never run the setup so I can only guess.
What are your temps like?

[pda75]

I have tried many prop. Here is a table with most of the results.

60681

When it states bumping, I mean that I have tried several angles for the strut and try to move the battery back and forward and did not get any way to avoid the bumping of the back of the rigger (I hope "bumping" is the right translation - it shows that the prop has too much lift).

Regards

Pierre

[pda75]

Any idea regarding the best prop ?

Pierre

[RaceMechaniX]

Pierre,

You might try some of the ABC props with a 20Deg rake. These tend to have low lift. Or for the tail hopping props try adding some cup to the tips. This will helo reduce the lift.

Tyler

[pda75]

thanks.
Have you tried propshop large pitch propellers like 5022, 5521, 6019 prop ?

[mm123521]

Pierre,

Just curious, how are you measuring your speed?

Mark

[RaceMechaniX]

Pierre,

I have tried the 19 series, but none of the 21 or 22 series props from the Propshop. The 19 series was OK, but I found better performance from modified Octura and ABC props.

Tyler

[pda75]

Mark

I measure the speed with two GPS. one on the top of the hull (in the back) and the other one is from eagle tree also on the top of the hull (in the front). Why two ? I have seen from very strange data with GPS (few years ago, I was measuring my own speed while skiing in the moutain. The GPS was on my arm. Once I stopped to have coffee. The max GPS speed of my arm while drinking was 622 km/h (eg 450 mph). I am not a heavy drunker ... but the story became famous !

Therefore, if the two GPS speed are very different I make a new run. With the eagle tree logger, I can also check that there is regular speed increase.

They get very closed data. (usually less than 1 km/h difference)

622310

[pda75]

some news.
After testing many props, I came to the conclusion that I need more rpm : I will exchange the motor for a 3040/11 and get new lipos

Regards

Pierre

[jaike5]

on my rigger, same size as yours , prop m62 x 80, sch 40/160 , 3060/8t I have no data for you , but you can spank the 90's doing laps on the out side. Jay