Tip tank

[Edouard]

Hello Gentlemen,
I'm thinking to install tip tank on my nipper GASXI.
Does anyone know where to found tip tanks and average cost!
Blue sky,
Edouard

[jockthenipper]

Hello Edouard,

Paul Grellier at Airweld still holds stocks of wing tank parts, he can be contacted at:

info@airweld.co.uk or,
12 New Barn Farm Cottages, Crawley, Winchester, Hampshire SO21 2PP
or,
Tel. 01962 776547
Mob. 07885 933514
Fax. 01962 776036

Having said that, you may wish to consider another recognised mod for the Nipper that was successfully incorporated by Neil Spooner that provides a similar increase in fuel capacity, but, places the new tank under the existing one. But, maybe you prefer the aesthetics of the tip tanks giving the wing a more 'finished' look?! Good luck whatever you decide .

Peter

[Neil Spooner]

Hi Edouard,
If you are set on fitting tip tanks then that is what you must do. They do look nice to some, I personally think they spoil the lines of the a/c if it has a good paint scheme.
I personally am against them (which is why I developed the mod' for the aux tank) as they are a pig to balance as any differing fuel pressure due to the vents will move the fuel from one tank to the other. The other main objection I have is that there is a strong possibility of fuel starvation if you don't switch tanks in time. If you have the Jab' engine with starter that is not an issue, but a VW once stopped is a bugger to airstart again. The aux' tank under the main transfers fuel to the main tank by a fuel pump, so you never have to switch tanks.
A better solution (one that I was working on) is to extend the bottom of the main tank with a triangular tank that fits between the brace bars under the main tank. In this tank fit vent and one-way valves to allow fuel to run into the bottom tank, but not allow it out when inverted. Fit a flop tube in this extension. With this set-up it will not be necessary to have a flop and a main feed so again saving weight. I think you should be able to fit about 15L in this tank.
Neil

[Edouard]

Peter, Neil,
Thx very much for all your usefull informations.
Of course the aim is to increase the range so now I know that there are
two possibilities.
I will think about that. I'd like to do the mod next winter then I still have a bit of
time to choose
All the best
Ed

[JimCrawford]

Does the standard mk 3 wing need any structural mods to take the tip tanks? The drawings I've seen show no reference to the tanks so maybe there is an extra set for the option. At the very least the fuel delivery tube will have to go down the wing if it is supposed to go in front of the spar then a bit of cutting and shutting to the leading edge box would be required and I wouldn't be overkeen to do that on nicely finished wing. Its probably a job for during a recover. If the tube goes behind the spar it may be enough to get access through the existing inspection panels, I'd be interested in going that route.
I think tip tanks enhance the Nipper but that's just a subjective observation. I wonder if they have a measureable effect on the wing efficiency by acting as end plates, that's just speculation on my part.
If the tanks deliver differently due to the vents, couldn't the vent lines be run down the wing and T'eed off into the main tank. That should sort the delivery.

If I remember correctly John Isaccs Spitfire had a diagonal brace in the tank bay, the aircraft is of wood construction so the brace tube was a bolt on part. The fuel tank had a clearance tube through it for the brace and would have to be assembled into the aircraft with the brace already threaded through.


Jim

[Neil Spooner]

The tip tanks have their plumbing on the fwd face of the spar, access hatches could be cut into the bottom of the LE, but would be a lot of work. It would be better done when recovering the wing.
The wing tips will need modifying to take the structural loads for the tanks.
The issue with fuel flow is entirely due to small differences in the venting of the tanks creating a small pressure difference, the tanks are connected in a T, but the issue is still a problem (ask anyone who uses them)
The tanks are made from aluminium, which will dent easily if miss-handled.
Best wishes,
Neil

[RobW]

There should also be non return valves in the plumbing, to prevent flow from one tank to the other if flown out of balance etc!

Oh and the tanks should be empty for aeros, the outboard mass has a big effect on polar moment of inertia, and subsequent spin recovery, so I'm told...

[G-ARBG]

As stated by RobW a non-return valve was fitted adjacent to each tank (type as shown) and a standard Auster 4 way fuel cock was mounted centrally in front of the pilot mounted on the spar.

David GARBG[attachment=0]non return valves IMG_0899.JPG[/attachment]

[Neil Spooner]

I have a complete set of pipes inc' valves for this set up on the unbuilt Nipper kit I have. If I do build this I will not be using them......make me an offer I can't refuse!!
Neil