General discussions - FAST RC boat

[jkflow]

Here is an inside view of that boat. He was pushing 1500A if I read that right.
Self-made batteries.

 

[rotauq]

Here is an inside view of that boat. He was pushing 1500A if I read that right.
Self-made batteries.

The main 'leads' where 1500A capable

 

[Speed/267]

This is just my experience.

 

[Sloclone100]

All the boats are running with water cooling, I wonder if that is even needed at times. Some ESC don't even break a sweat in a car and motors stay fairly cool as well. There must be some other magic that I'm not aware of, the last boat I ran was scale and had a resistive 'ESC". Some new stuff to learn.

Boats are not very innovative, and some people might not even realize these things.

Well, My brother has several R/C submarines, all fully. In fact, they were using gyros way before us. Back in those days, they managed to take a helicopter gyro and put it on its side. Of course, when the surface gyros came along, it was a whole new game. Using pressurized air, going up or down is easy. Stabilizing control is every sub-makers task. To be able to go a certain distance, underwater, with just your periscope cutting the surface, an inch or two. You know, since submarines are considered "boats", and surely deserving the term "innovative", which means you do not 'realize' some things. My brother owns fully operational television subs like "Voyage to the Bottom of the Seas", "Fantastic Voyage", and even Captain Nemo's "Nautilus". Most of his collection is modern-type nukes. Some of his modern-era subs fire compressed air-powered torpedoes, with a surprising range. Yes, sir, these "boats" are very innovative.

 

[LibertyMKiii]

Slowly getting this mono hull setup. It certainly has more steps than I had realized.
Plus there is lots of waiting periods of 24-48 hrs for the epoxy to setup.

-Fiber glassed the inside of the hull to fill the hole on the bottom and rear from the old gas/nitro setup.
-Followed that up with some epoxy over the holes from the outside. (still need to sand it smooth and re-paint.)
-Mounted the new stinger setup and rudder.
-Stuffing tube sized and cut + epoxied in place.
-Cut some carbon fiber plate to make a tube brace, then epoxied in place.
-Epoxied in the motor mount and have it aligned with the 3/16" flex shaft for minimal bend in the shaft.
-Setup the drive dog placement and prop.

To Do List:
-Mount the servo
-Setup servo push rod
-Mount the Receiver water proof box
-Mount the ESC
-Make some tabs for the hull hatch lid.
-Battery holder
- Trim Tabs
-Turn fins
-stuff the nose with pool noodles

 

[LibertyMKiii]

Met up with some locals that race RC boats. They were doing a practice session before this Saturday's race.
They are expecting 120+ boats at the race. I am going to try to make it out there, but will have the baby as my wife is out of town and no telling how that will go

Snapped some pictures while out there.
Really nice group of guys.... I can see myself getting into this although I don't care for circle tracks or racing.
Another plus is they bring out a small fishing boat for fetching your dead RC boat.

One of the 2 stroke gas hydroplanes was doing 70+ mph I would estimate.

This guy's boats were all about scale realism. Some very nice looking boats:

He said pictures were a dollar each so I took off running...

 

[Doom!]

Nice, I don't need any more hobbies, thankfully there is no water near me that is convenient!

 

[LibertyMKiii]

Nice, I don't need any more hobbies, thankfully there is no water near me that is convenient!

I honestly don't need any more either, but this one is paying for itself. Paid $150 for the lot of 12 boats and various nitro motors and have now cleared around $1,000 selling most of them off.

 

[jkflow]

This one takes the cake. I'll see if I get a heads up on the maiden and be there in person. It will be Epic.

 

[LibertyMKiii]

This one takes the cake. I'll see if I get a heads up on the maiden and be there in person. It will be Epic.

Never seen a RC boat perform well with a turbine motor.
Should be interesting to see how it does.

 

[Doom!]

How does the turbine work with propulsion? I see a prop but not sure how it all connects. Wouldn't it be better to use something similar to a jet ski? I really have no clue how these things work....hey! stop laughing!

 

[jkflow]

No idea either, need to see this in action though.

No, jet ski etc is very limited in speed, you will get something called 'stuffing the prop' at high speeds and that will kick you off like a bucking bronco. By all means, it's very good up to ~ 90mph or thereabout. You probably have to design some fancy nozzle that dynamically allows more or less water into the inlet but not worth the effort.

 

[LibertyMKiii]

How does the turbine work with propulsion? I see a prop but not sure how it all connects. Wouldn't it be better to use something similar to a jet ski? I really have no clue how these things work....hey! stop laughing!

Turbines have an extremely high rpm...
My assumption is some gear reduction output to drive the prop.

Like idle speed is 85k rpms and max is near 250k!!!!!

 

[Sloclone100]

Met up with some locals that race RC boats. They were doing a practice session before this Saturday's race.
They are expecting 120+ boats at the race. I am going to try to make it out there, but will have the baby as my wife is out of town and no telling how that will go

Snapped some pictures while out there.
Really nice group of guys.... I can see myself getting into this although I don't care for circle tracks or racing.
Another plus is they bring out a small fishing boat for fetching your dead RC boat.



One of the 2 stroke gas hydroplanes was doing 70+ mph I would estimate.


This guy's boats were all about scale realism. Some very nice looking boats:



View attachment 157597

He said pictures were a dollar each so I took off running...

That looks like a great afternoon. How are the deep-vs' doing against the hydros and cats? Thanks for a great share.

No idea either, need to see this in action though.

No, jet ski etc is very limited in speed, you will get something called 'stuffing the prop' at high speeds and that will kick you off like a bucking bronco. By all means, it's very good up to ~ 90mph or thereabout. You probably have to design some fancy nozzle that dynamically allows more or less water into the inlet but not worth the effort.

The saying 'stuffing the prop'. I that caused by cavitation?

 

[jkflow]

No, at a certain speed, you are pushing too much water into the jetdrive. From what I understand, you are creating a shockwave inside the tunnel once that shockwave reaches the prop, it is no longer able to expel the water fast enough and the intake flow will stop completely for a brief moment. Keep in mind that the water intake is aided by forward motion. I'm sure there is some better physics behind it but not an expert on it.
This is what happens, and many people have found out that it is real. It does vary between pump design, but they all have an upper limit.

 

[jkflow]

Now this is the way to go!

My Talion and @Uplift-RC 's BlackJack (black). Swapped with another one (white) on the owners self-build trailer.

Pick one!

Video of Insane turbine boat spool-up test coming shortly.
Some fun facts, Turbine @850k RPM down geared to 35k RPM at prop. Currently propped to do roughly 120mph. Maiden run next weekend!
8oz fuel per minute

 

[jkflow]

Video is up on @Uplift-RC youtube site. Suggest subscribing, next week will be the actual run.

 

[LibertyMKiii]

Our 42.5" v-hull is nearly ready.
I decided to buy the kids a WL-Toys RC boat to learn on now that we have some $$$ invested in this beast.
That little WLToys boat goes around 20mph and is really fun for $36.00 shipped to your door!

 

[jkflow]

Just finished my rescue tug from Zippkits, back to actual building some stuff! (never again even though this was simple).
Build was ok, but painting in Florida is impossible, paint won't dry unless humidity is below 50% and below 90F. Stinking up the house didn't go over well

It's a little beefed up over stock (1000kV vs stock 650kV), and it moves, but not 20mph. For retrieval, you will need good steering and this one turns quickly. I'll probably add a fork to it.

 

[Doom!]

@jkflow Gonna need some rescue stickers!