Endbell Heat Sink

[Shooter]

To me adding 9oz is adding 9oz.

You're right. 9oz is still 9oz in the vertical downward direction (1G), but it's the horizontal force that's acting to pull us out of the turn that's killing us.

9oz in a 12lb boat is only 5%. My boat is more like 6lb, so it's 10% which starts becoming significant. Every little bit counts.

[T.S.Davis]

Kinda irrelative, by the same math a 12lbs boat would b 50.4lbs. To me adding 9oz is adding 9oz. I could b wrong...

Jason sims

That is correct. 12 pound boat is 50 pounds in the turn.

9 oz is 9 oz......in a straight line. Once you turn it becomes more than 9oz. It's 9 oz x G force. If that 12 pound boat weighed 9oz less it would only be 48 pounds on the turn fin. That's 2 pounds less to accelerate out of the turn. It's still only in theory. The boats don't make an actual 40 ft radius. Their sliding all the way through the turn. If they were really on rails like some of us claim is would be 48 pounds.

Another way to think about it is the less weight you add to your fin the smaller that fin could be. Less fin is less drag. Less drag needs less power to maintain speed......or use the same power and just go faster.

The fin on my Whip is gigantic and thick. Plus it's anchored to the tub at the trailing edge. The boat turns in around 60....ish. At 60 the numbers get even more stupid. That's 6.05G. Like I could really pull off a 40 ft radius with that boat. At 15 pounds or so I've got 90 pounds hanging from my turn fin at the apex. Yikes.

All theory though. So many factors that aren't constant in this silly hobby of ours.

Tangent. Sorry guys.

[line6]

All good points. I think your theory is correct. It cant NOT weigh more in a turn. I just look at it as adding the weight your adding. because the % off weight added stays the same.

Jason Sims

[Shooter]

Right. A 6lb boat still weighs 6lb. What Terry is talking about is the additional force that is exerted opposite of the acceleration in a turn.

The acceleration is towards the center since the velocity is changing direction and the resulting force is opposite of that acceleration. The force is essentially on the turn fin holding the boat.

6lb boat. Mass = 6/32.2 = 0.19slugs

In a 4g turn, the theoretical force on the turn fin is 4*32.2*0.19 = 24lb

See you out at practice!

[Shooter]

Back to the endbell sink...

I ran an H5 S/B prop last night. It was approx. 85° ambient temp. Ran 7 laps. I pulled the tape off immediately after the run and I could easily hold my finger on the endbell. That's a good sign. I will have to look into other ways of attaching it, or possibly making it integral to the cooling sleeve.

Oh, and apparently this rigger was pulling some serious g's whilst the driver was sawing some serious z's. Right through me in the turn!!! Unbelieveable!

2012-08-08_17-59-08_556.jpg2012-08-08_17-55-26_477.jpg

[monojeff]

What about a larger diameter cooling jacket meaning more volume would this help with temps?
I am running a blue SV motor in my 1/10 scale vintage boat and my temps are around 135-140 at the moment with a cupped 447 running mid 40's boat weight is about 5.5lbs.

Tony where did you get the fan from if you can pm me with the info and wondering how much it actually helps??

[Alexgar]

I have one on my slash 4x4 slash rev and it works great

[Alexgar]

Do a search for 30 mm dc fan they are readily available at computer stores like radio shack or frys

[properchopper]

What about a larger diameter cooling jacket meaning more volume would this help with temps?
I am running a blue SV motor in my 1/10 scale vintage boat and my temps are around 135-140 at the moment with a cupped 447 running mid 40's boat weight is about 5.5lbs.

Tony where did you get the fan from if you can pm me with the info and wondering how much it actually helps??

A larger cooling jacket wouldn't hurt - I've had that same thought. Two things to consider however : Cooling the can isn't all that effective in reaching the wire entry point or inner workings, e.g. the rotor. Setup and runtimes are of primary importance in heat management.

I get my fans from a friend who dissasembles computers. They're available at most electronic supply stores. One prob is that most of them are rated for 12V so 4S can burn them out. I'll see if I can find links.

I honestly can't tell how well the fan does; by the time I untape the fan's already cooled down the wire-end (which is the most frequent burn spot). Still, like Saturday's race where the local temps are sizzling I'll use a fan (most likely).

[properchopper]

I've used the second one down the page; it'll blow the feathers off a duck !

http://www.smcelectronics.com/fan.htm

[Alexgar]

Tony I run mine off the voltage output or 3 rd channel of my rx

[oldnfat]

Pete, I knew you were going to post those pics; I cannot express how guilty I feel about taking you out with the rigger.

It is hard to handle that boat, different speeds require different amounts of steering input, its all over the place.

And so everyone else knows, I did offer my brand new un-built Phil Thomas as a replacement, I know it doesn't make up for all the hard work and nice paint job you did on yours but that offer will stand forever. :)

I will get you whatever you would like to pay you back, minus hookers or a trip to Hawaii, but anything else is your bro. :)

Sorry again.

[MassiveOverkill]

I get my fans here: http://www.performance-pcs.com/catalog/index.php

Of course it doesn't hurt that they're located 5 miles from me.

[Shooter]

Mr Fab - Don't worry about the boat! Appreciate the offer though!

So, here is my first stab at an integral sleeve/endbell cooler. A cap will be tig welded to the end and water will flow from bottom up over the fins (separate from the sleeve flow). Might even get some additional cooling on those wires everyone talks about. Who knows. Any advice/comments are welcome. I'll hit the lathe/mill when I get some time.

sleeve.jpgsleeve2.jpg

[LuckyDuc]

Want to make your head hurt some more? The prop you can get away with on our pond might not work on the next pond you run on. Different crap in the water. More iron? Water dye? Elevation above sea level? Beats me. I don't know how to quantify it but it's real. You have to test on the pond you're going to race on. Makes open water actually matter. Tom burned up some stuff in Canada that he races on our pond with no trouble. How come? IDK!!

There is a lot of truth in this statement. I keep a little note pad listing what props I can run based on water temps/conditions.