Let's talk nipples

[Marty_d]

That got your attention!

 

I need to put a nipple on the lid of the square plastic water overflow bottle so I can run a thin tube down to the bottom of the firewall.

 

What have people done with that?

 

The nipple needs to have a 90 degree bend because the top of the bottle is quite close to the cowl.

 

I can get something like this:  https://www.prospeedracing.com.au/products/brass-1-8-npt-90-degree-3mm-hose-barb-fitting-pro-speed-racing - but because it's NPT I can't put a nut on the inside of the lid, and I reckon the plastic is too thin to tap with a 1/8 NPT thread.

 

Any ideas?

 

Thanks, Marty

 

[Blueadventures]

37 minutes ago, Marty_d said:

That got your attention!

 

I need to put a nipple on the lid of the square plastic water overflow bottle so I can run a thin tube down to the bottom of the firewall.

 

What have people done with that?

 

The nipple needs to have a 90 degree bend because the top of the bottle is quite close to the cowl.

 

I can get something like this:  https://www.prospeedracing.com.au/products/brass-1-8-npt-90-degree-3mm-hose-barb-fitting-pro-speed-racing - but because it's NPT I can't put a nut on the inside of the lid, and I reckon the plastic is too thin to tap with a 1/8 NPT thread.

 

Any ideas?

 

Thanks, Marty

 

Make a nut from 3mm flat and tap thread. Will work.

[Thruster88]

You could drill a hole into which the plastic over flow tube would fit tightly. Can cut the tube at an angle so it can be pulled through then cut off. Some slack in the tube will allow the cap to be removed. 

[skippydiesel]

Hi Marty,

 

Is this a Rotax 912 installation?

 

If so, Why do you need an overflow tube?

 

I am on my second 912 powered aircraft - neither have an overflow tube, from the the expansion tank.

I have never experienced coolant overflowing from the expansion tank.

Assuming correct installation & filling of the coolant system, the cold level for the expansion tank should be 1/4 to 1/2. This will leave more than enough room for the hot coolant to be contained within the expansion tank.😈

 

 

[Moneybox]

3 hours ago, Thruster88 said:

You could drill a hole into which the plastic over flow tube would fit tightly. Can cut the tube at an angle so it can be pulled through then cut off. Some slack in the tube will allow the cap to be removed. 

I think Skippy could be right. The bottle has plenty of room for expansion. If you go with the suggestion of a neat fitting washer and a nut inside seal it with an o-ring so that it doesn't need to be tightened. Most plastic won't take compression very well without fracturing.

 

If I was doing it, but I won't, I'd go with Thruster's suggestion only I'd insert the hose through the side of the bottle not the top. That way it would not come near the cowl and would never have to be disturbed. Use a soft rubber hose rather than a clear plastic.

Edited February 9 by Moneybox

[rgmwa]

The square bottle on my 912 just has a small hole in the cap with moulded filler marks as Skippy said. Why do you need an overflow tube? 

[onetrack]

You should never lose coolant overboard at any time, under normal operation. Coolant lost is cooling ability reduced.

[Moneybox]

8 minutes ago, onetrack said:

You should never lose coolant overboard at any time, under normal operation. Coolant lost is cooling ability reduced.

Coolant in that bottle doesn't get to circulate or play any part in cooling the engine. It's just there to handle expansion and some may return to the cooling system as the engine cools. 

[onetrack]

Well, it does get to play a part in engine cooling if it returns to the cooling system.

[BrendAn]

Skippy is correct.

Why do you think you need an overflow hose. 

[Red]

 

Fitting a line there wont do any harm but, If the valve in the coolant cap is blowing out enough coolant into the expansion tank (plastic bottle) for it to overflow then you probably have a lot more to worry about than a bit of mess on your firewall.

The hole in the cap is really only an air vent there to prevent the expansion tank itself becoming pressurised not to as an overflow

 

Admit it Marty....you just wanted to talk about Nipples😁

Edited February 9 by Red

[Kiwi]

12 hours ago, Marty_d said:

That got your attention!

 

I need to put a nipple on the lid of the square plastic water overflow bottle so I can run a thin tube down to the bottom of the firewall.

 

Try a right angle mag wheel tyre valve, just make sure you remove the valve core.

[Marty_d]

8 hours ago, rgmwa said:

The square bottle on my 912 just has a small hole in the cap with moulded filler marks as Skippy said. Why do you need an overflow tube? 

I like this solution as it doesn't require me doing anything.

Mine has the small hole too, I had assumed it was the pilot hole for the nipple but it may just be for pressure relief.

Thanks all, the general consensus seems to be that it isn't needed so I'm happy with that.

[Red]

As an aside, a fellow Rotax user I know once priced that square plastic Bottle and was quoted about  150 aud!

Needless to say he used something else.

[Marty_d]

I was lucky, a very generous person on here gifted it to me!