Sue and Bill Sisley
-------- Original Message --------
Subject: Re: Europa-List: XS Fuel Tank
Date: Fri, 21 Mar 2014 16:35:46 +1300
From: bill <bill.sue@orcon.net.nz>
A very happy day as ZK CHV is now back in the air complete with a new
aluminium fuel tank.
After much deliberation I settled on 2mm aluminium to a design that
eliminated all the complexity of the plastic tank but increased the
volume to 85Ltrs. The structure was formed by a continuous fold from the
rear bottom and over the top to front bottom. The sides and bottom are
one fold each side and one piece tunnel all flange welded for strength
with cut-outs and inserts to clear controls.
I made the tank narrower that the previous to allow it to drop straight
in without having to stretch the fuselage and 100mm taller for extra
volume. No internal baffles were required as the tunnel and cut-outs
provided sufficient rigidity.
The outlets and breather are all AN fitings with provision for separate
water drains and fuel outlets left and right and the fuel return back to
the inside of the starboard tunnel.
The tank sits free with the bottom rear of the tank sitting on a flange
off the rear wall of the cockpit module and the front sitting on a full
width flange off the front wall (seat-back) of the module. A rubber pad
is glued to the tank at all contact points preventing chaffing. The
original spacers are retained to prevent fore-aft movement.
I raised the sides of the cockpit module to just level of the door sills
and continued the same angle for the head rests so they are now slightly
further to the rear.
Fuel is measured with a capacitance probe calibrated in 1 litre increments.
Reserve fuel on the starboard side is 14 litres.
Some pics attached.
Sue and Bill Sisley
On 12/11/2013 10:38 p.m., nigel_graham@m-tecque.co.uk wrote:
> Hi Bill
> If you are serious about constructing your own alloy tank, here are
> some of the issues that I considered carefully before embarking on
> what turned out to be a lengthy project.
>
> Capacity
> If you want to maximise capacity, the tank shape will be complex to
> take advantage of the available space. I went "full span" and put
> seamless tubes through to accommodate pitch control and rudder cables.
> Since you have sawed off the top of your cockpit module, there is now
> room to extend the tank vertically up by about 100 mm (to the door
> sill), this should give you an extra 18 litres. Restore the strength
> of the CM joint using standard "good composite practice".
> This should not compromise the seating or baggage-bay access.
>
> Mounting
> The tank cannot sit on the bottom of the fuselage but should be clear.
> Incorporate supporting brackets to spread the (considerable) load to
> the front and rear of the cockpit module (seat back). Design in some
> method of allowing the tank to expand and contract - sitting it on a
> rubber or cork mat for instance.
>
> Breathing
> Use considerably larger breathers than were originally fitted - to
> prevent pressure build-up and blow-back while filling. If possible use
> two, one on each side of the tank. I routed mine up and then down,
> venting under the fuselage, to prevent siphoning or fuel dumping in
> the event that the aircraft ever flipped over.
>
> Fuel Return
> I pondered the ideal configuration for the fuel return line (discussed
> ad-nauseum since!) and opted to return it to the top of the tank. A
> vertical cross-drilled pipe inside the tank allows the fuel to dribble
> down without vapourising or having to contend with the back-pressure
> of a full tank.
>
> Fuel Level Monitoring.
> There are now far more options available to accurately monitor the
> fuel contents. Capacitance level sensors work well but are sensitive
> to fuel type, if you only ever use one type of fuel, this won't be an
> issue. They can be used with a "lookup table" to linearize the readout
> giving an accurate indication of fuel contents. Float switch stacks
> are the next option, (as supplied by Europa) they are reliable and not
> fuel sensitive but give a non-linear indication. I opted for the
> former but included four optical sensors to give an independent
> indication of fuel contents at "Full", 2/3 1/3 and "Reserve" and chose
> to delete the standard "stand pipe", which, without any method of
> isolating, I considered a safety risk.
>
> Maintenance
> Now is a good time to include an inspection hatch. Machine a large
> diameter "weld-in" ring with matching cover, tapped for at least six
> bolts. Include a groove to accept a Viton "O" ring to seal the joint.
> This cover also makes an ideal mount for the fuel level sender.
>
> Good luck and keep us informed of progress.
>
> Nigel
>
>
> On 11/11/2013 22:43, bill wrote:
>> Thank you Nigel,
>>
>> Having got the top off now I can see that the leak is at the shelf on
>> the front of the tank where it sits on the mount. It appears that the
>> fibreglass had bonded to the tank and with movement caused a fracture
>> due to the stress. Having looked at the tank now which is very
>> deformed and reducing capacity, I am sure a "metal" one will be much
>> superior. Fortunately there are some very good craftsman around here
>> so fabrication will not be a problem. Not sure we will get to the
>> same volume as you have but will certainly look for more than I have
>> now. Will send some pic,s when all done.
>>
>> Regards
>>
>> Sue and Bill Sisley
>> On 12/11/2013 8:55 a.m., nigel_graham@m-tecque.co.uk wrote:
>>> Hello Bill,
>>>
>>> I'm a bit late getting back on this one but as others have said, I
>>> built a tank out of 5251 quarter-hard magnesium alloy.
>>> It weighs 7850 grams and has a capacity of 110 litres.
>>> I incorporated internal baffles, and breathers with proper AN
>>> fittings to accommodate alloy pipework. It is also fitted with a
>>> full length capacitive probe and four solid-state optical fuel level
>>> sensors.
>>> http://www.europaowners.org/main.php?g2_itemId=28719
>>>
>>> The only advice I would offer is: allow yourself a long time to make and
>>> perfect
your cardboard templates - the fuselage is partly conical in section so
the development will be an interesting shape. Choose a welder based on his
ability
to weld alloy and don't fall into the trap I did of restricting yourself
to a CAA approved welder whose self-belief exceeded his ability!
>>>
>>> Nigel
>>>
>>>
>>> On 08/11/2013 21:37, bill wrote:
>>>>
>>>> After 1100hrs I have suffered a failed fuel tank on my XS Mono. Not
>>>> sure exactly where the fault is other than it is high up on the
>>>> tank. Will know more when I get it out.
>>>>
>>>> My question to the forum is, has anyone tried fabricating a metal
>>>> (aluminium) tank rather than using the Polyethylene plastic one as
>>>> supplied with the kit. If so, were you able to obtain the same
>>>> volume and any other advice you may be able to offer.
>>>>
>>>> Many thanks
>>>> XS Mono
>>>> Kit 456
>>>> 914 and Airmaster
>>>> 1100hrs
>>>>
>>>>
>>>> Sue and Bill Sisley
>>>>
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