Mounting for a funnel

Mounting for a funnel in order to fill water tanks

There is always a need to use a funnel if you intend to fill a water tank in a sailplane.
You probably know that you should never insert the water hose directly into the wing. The wing has to withstand a pressure of 0.3 bar – according to manufacturing rules and regulations. The water that comes out of a water hose is at up to about 6 bar. You would not be the first pilot who would manage to wreck a wing if you’d decide to use a water hose in the described way.
Well, but there’s a question: Who can hold on to the funnel once you intend to fill up your tanks? Here’s a small construction for you to help you out. You simply apply (as described) a rubber band to the wing and the mounting will work on both – double and single seat sailplanes. Take a look at the drawings of that mounting. If you like you can also enlarge the plan (Click!) and feel free to build the mountings yourself. Have fun!
By the way: The best method for filling up the tanks would be the use of canisters  – that would enable you to have an equivalent amount of water in both wings.

Did you know:

A water pipe is commonly set to carry water at a pressure of 6bar? A wing will burst at 0.3 bar!
Therefore – do never attempt to fill a wing by means of a water pipe.

Water Refilling System by DG:

The refilling by use of two submerged pumps is no doubt a save and comfortable way compared to the use of a funnel. We have developed a system which is available for sale by now. But we’d like to describe the set up in detail in order to enable you to build a similar system by yourself.

The system is derived off an idea by Ch. Hostettler, which is common knowledge among most pilots. The first system describes a simple refilling solution. A standard hose can be attached to the funnel. A late closure of the water tap can only result in an unwanted shower.

This system is suggested for LS8 or DG-808 gliders equipped with integral tanks. The reason fort he long standpipe is the requirement of the wings being leveled in order fort he funnel at the leading edge of the wing to develop enough water pressure in a reasonable amount of time. The use of water bags does not require a sophisticated solution.

The easy version is good enough. Nice and effective water clocks are available by now – giving you a means of measuring the amount of water in each wing.

An other option is the refilling by means of submerged pumps. The upwards facing pipe in the picture is a relief pipe for the pressure.

The two technical drawings should enable you to build such a system by yourself.

Water refilling System with
Pumps – Standard Version

The system in use for the DG-808S (and LS8/ later also LS10) will be slightly different (you’ll see it when you look at it a bit closer).
The pumps in use for integral pumps require a unidirectional restrictor valve. The water will flow out of the tank if that valve is not put into place.

Refilling System for Integral Tanks

– friedel weber –
– Translated by Thiemo Gorath –