This Electric Stuff Is FUN!

[Propjockey]

Got bored yesterday and swapped out the Mabucci in my retrieval boat for a LeMans 05 race motor. Pulled the V937 off Hydro-plow and stuck it on the shaft. Already had the 2400 Nicad pack.

This thing took off like a scalded cat! I know, I know...it's not LOU's 40 MPH Villian, but still!

Since I was just testing, I didn't have the hatch on. Yup, you guessed it. First hard right it dug in and swamped! I stood on the shore and watched the back end sink till there was about 6 inches of the nose bobbing straight up in the water.

Hmmmmm...what to do? I figured, it was already wet so, what the heck! I goosed the throttle and it actually pushed itself up out of the water and back to shore! (they don't go as fast when they're full of water)

Dumped the water out and got stupid..."Run it some more!"

(well, I had to dry the motor out...right? ;D )

About two minutes later, it quit. I could hear the motor running, but no go. Brought it in with the fishing pole and the plastic U-joint was MELTED OFF! Battery pack was warm, but the motor was too hot to touch!

My question is this--

The prop is under the hull, completely submerged at about a 15 degree down angle on a solid shaft. (remember, this was a low buck retrieval boat)

If I water cooled the motor and ran a flex shaft out the back to a strut so the prop is surfaced at 0 degrees, would it run even faster?

Is the V937 too much?

The running attitude was decent...nose up about 5 degrees (amazing, considering the angle of the prop!)

 

[Finne]

well mathematicaly speaking, you would aim all of the thrust backwards, instead of sending some of it downwards. So you probably would gain a bit of speed yes.

But then you would at the same time have the thrust pointed a bit below the CG.

That should make the boat dig in more at the back adn lift the nose alot more.

....and then you have the "prop helping lifting the boat out of the hole" thing.....

it goes on and on.... ;D ;D

try it and see what happens?

 

[Climate Boatworks]

V937 + direct drive 05 = smoke

Thats a prety big prop for a little motor. Probably the only thing that saved it was that you are only running it on 6 or 7 cells. Any more would have burned it up good.

Try an X432 or X435. A better sized prop will let the motor unload and will give you longer run time and much longer motor life.

Peter

Visit www.climatemodels.com

 

[Propjockey]

Thanks Peter. What do you think about the strut idea?

 

[Andrewg]

PropJ.

the surface drive wont work as well for as a retrieval boat. The V937 is too high a pitch. The prop depends on the can - is it an ap36L ? that motor likes a X435 at least but the v937 is simply too much load except for saw

The surface drive will probably work ok if the hull is flat from about 50% of the keel to the transom and you remove the skeg

Depending on the wind and can length watercoling and a prop between x427 and X632 in a submerged configuration will get you good speed runtime and good thrust for a pickup boat

Andrew Gilchrist

fastelectrics.com

 

[Propjockey]

Heck, it's too much fun to use as a retrieval boat now!

I WANT SPEED! (cheap)

What setup will give me the most speed with the motor and batt I have now?

Sanyo 2400 6 cell

Kyosho LeMans 05 Stock Racing motor

(I also have a Kyosho Mega Monster in a 4WD that could be sacrificed)

 

[Propjockey]

This looks like a whole lot more motor than the LeMans.

Same prop recommendation? Or will this be able to swing a bigger prop?

 

[Propjockey]

end bell

 

[Andrewg]

proabbly withthe lemans which is a stock motor - 27 turns - which is simply indicative of he rpm and power output a x432 or x632 would work well

to go fast get another hull if you like kits the electrified from Air Age ie Radio Controlled Boat Modeller would make a nice first boat and suit the Kyosho mega

A word of caution - the car motors youar eusing a ok in cars but in boat where current draw are cnsistently high the fall down particularly in relation to wear rates. Yur motors are mild turns and should be ok for a while.

However there are better longer lasting motors around which are well worth the effort.

Also micro baots - less than 20" are growing in popularity and are the cheapest way to go 30 mph with a tiny baot - a real bast

Andrew

fastelectrics.com

PS How long is the hull you are using or what type is it.

 

[Propjockey]

Don't know who made it...bought it off eBay.

22" long

 

[LOU]

Looks like a surface drive would work good and be faster. Is the transom straight? How much did you get the hull for? Probly cheaper to stick with the submerged drive. I would also say your the first person Iv'e ever heard try a V937 subsurface Man I wish I would have tried that ;D

LOU

 

[Dennis Whitt]

That hull is a Ware house Hobbys hull made some 8 years ago.He originaly made it for a MRP outboard.But they became unavailable after MRPs demise.

 

[Propjockey]

LOL...Thanks LOU.

I paid $19.95, new. Had to do some trimming to get the deck on right, but it wasn't hard.

The transom is a bit more than 90 degrees from the keel, but nice and flat. If you think surface drive will get more speed, I'll scratch built the hardware.

(I don't think the motor liked the prop under the hull ;D )

Will the Mega pull the V937 if it's run on top?

BTW...here's where I got it...the price went up, but the shipping is free now.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...&category=19166

 

[Andrewg]

Propj surface setup will work fine

937 seems too big for the mega - but try it - watch the heat - its unlikely you will get good handling or long run times

y536 is proably more like it better blade shape

Andrewg

www.fastelectrics.com

 

[Propjockey]

Thanks everyone! Looks like I've got MORE hardware to build. I'll keep ya posted!

 

[Andrewg]

Prop J just a rudder

you can simply extend the stuffing tube and run a couple of teflon bushings in it and it will be very effective. Just run it flat.

Andrewg

www.fastelectrics.com

 

[Propjockey]

Should the stuffing tube come straight out from the lowest point on the transom, or from underneath the hull?

 

[TRUCKPULL]

Straight out from the lowest point on the transom.

This was a Kyosho Viper.

 

[Ron Olson]

The boats I have built have the flex cable mounted slightly above the bottom but that's me. had less handling problems that way, especially with chine walk.

TP, how strong is that extension that you made? I'm thinking that it might twist the first time that you make a hard turn. It's not that clear in the shot. I would have put the water pick-up on the right to get more water flow.

 

[AValentine]

A picture to give you ideas on home built hardware. The pic shows a Hughey strut and Fuller's wedge rudder. While this is for a 27" Electro Vee it will give you some idea's.

I'd try a smaller prop submerged first however. Pick up a couple plastic x431 or y531's to try if you have an 1/8" shaft. $1 vs $10-15 for Berylium and they won't need to be balanced.