Enlarging the Water Pickup Hole on the Rudder...

[Capt. Crash]

....anyone done this?

It's getting hot here again and my stock UL-1 motor is running a little warmer than I like at 120+ degrees after a 1 mile run. Everything else is very cool...using the stock routing....in to ESC to Motor back to ESC then out. I need more motor cooling and already drilled out all the fittings on the stock cooling can and ESC and went to a little larger ID tubing. The only place I can still improve is the rudder. I can't change the motor in/out postion and still get my cowling on (this is not in my UL-1), so I have to improve water flow where things are.

Has anyone drilled the rudder out to get a bigger hole with better flow? Did it help? If so...how did you do it?

BTW...I just added a small 5V electric fan powered off the receiver to blow into the front of the motor...but haven't had a chance to test it yet. It doesn't push much air but may help some. Maybe at least it will help to keep the motor from cooking off in the first few minutes it's trying to cool after pulling it from the pond. That's when I tend to see/smell motors get cooked the most often.

Crash

[JimClark]

What prop?

[longballlumber]

I haven't tried this yet, but make sure the cooling line "path" thru the rudder is clear of burrs left from the machining process. I have found the Aqucraft brass fittings have alot of burrs, I would suspect the rudder could be the same...

Later
Mike

[Capt. Crash]

What prop?

Jim it's the X442 on the Bardahl. I like the performance but am running a tad warmer than I like.

[JimClark]

Is it just stock sharpened and balanced?
No cupping?
How long does it take you to run a mile?
how and when are you measuring the temp?

[Capt. Crash]

Is it just stock sharpened and balanced?

Yes...just sharpened and balanced

No cupping?

No

How long does it take you to run a mile?

About 2 min.

how and when are you measuring the temp?

Temp gauge at esc, connectors, multiple readings outside can & cooler and inside can as soon as i can get her unbuttoned....usually with 1- 2 min of the end of the run.

Here is a video of a typical run just over a mile. 6 laps is one mile at this pond. Speeds top at about 40ish....best is 42.8mph.



I added a pic of the temp gauge.

[JimClark]

she still looks a little nose down to me. I would check the following.
1. Burs in the cooling system and make sure tere is nothing pluging the system up.

2. Make sure your shaft is lined up well with no binding and if you are running bearings they are lubed.

3. I realize it was windy in the video but I would move the CG back a little to get a little more air under her and free it up a little more.

4. looks like you are slowing down a fair amount in the turns also.

Jim

[Capt. Crash]

I've done all the above. The video was of an early run ...I've freed her up some since. The air and water temps are rising here...90 out today....so the rest of the temps go up too. Maybe the fan will help. Here are some pics of the stock setup...i've not done anything to the rudder other than run a drill bit down the fitting.

I really want to know if I should and how to drill out the intake hole with out messing things up.

[detox]

Sharpen your rudder.

capt,

Dont file the hole. better yet make sure the leading edge of the rudder blade meets the front tip of the hole.. You can do this by sharpening the starboard side of the blade (the right) until the water pickup hole meets the leading edge.

Or

You can use a burr and elongate the hole to the leading edge..

Did any of that make since to.. cuz it hardly did to me and I said it!

Grim

[mdunham]

Diesel 6401 has an sv and a ul-1..check his posts on this issue!!

[scoota]

I had the same heat issues & by running the pick up behind the prop & running copper tube thru the hull to eliminatethe chance of the water tubing being restricted & by doing this i cut my running temps in half

temp 1 - caps

temp 2 - ecs

temp 3 - motor

[Capt. Crash]

I had the same heat issues & by running the pick up behind the prop & running copper tube thru the hull to eliminatethe chance of the water tubing being restricted & by doing this i cut my running temps in half

temp 1 - caps

temp 2 - ecs

temp 3 - motor

Thanks Scoota...but that won't work for me as my strut is internal and I have no wiggle room to reroute the intake there. See pics....I need to improve the flow of what I have in place. I can't move any fittings or tubing. I already tried 90 fittings on the can cooler too... and I still can't rotate my cooler and get my cowling on with them on the top of the can. I want to keep the appearance of the tubing as clean looking as possible too.

I forgot about the post by Grim....he is saying to NOT file out the hole but then says to make it bigger (longer) to meet the leading edge of the rudder or sharpen the rudder till it meets the hole. I will try to sharpen the rudder and do that.

Why would it be bad to make the hole bigger in diameter?

[Grimracer]

File the starboard side of the rudder blade until the water PU oval meets the leading edge of the blade.

Your not really making the rudder overall thinner, you are just removing material at an angle.

do you understand?

The oval becomes elongated.

Grim

[Bajasickness]

I had the same heat issues & by running the pick up behind the prop & running copper tube thru the hull to eliminatethe chance of the water tubing being restricted & by doing this i cut my running temps in half

temp 1 - caps

temp 2 - ecs

temp 3 - motor[/QUOTE]

Hey Scoota,
What a great idea of the water pick up behind the prop...where did you get that bracket for the pick up?

[scoota]

I had the same heat issues & by running the pick up behind the prop & running copper tube thru the hull to eliminatethe chance of the water tubing being restricted & by doing this i cut my running temps in half

temp 1 - caps

temp 2 - ecs

temp 3 - motor

Hey Scoota,
What a great idea of the water pick up behind the prop...where did you get that bracket for the pick up?[/QUOTE]

Its cut down blackjack 26 pick up ...

[larryrose11]

IM facing a similar issue. The pickup is the smallest diameter of the cooling circut, not good. My solution was to fit a square brass tube on the back of the rudder. I found stock at the LHS that was the dame thicknedd as the trailing edge of the rudder. I have yet to try this, but I will next time I run this rigger.