Model Forum / Radio Controlled / Air Models / August 2004

Not familiar with the exact tank you are using, but you might want to
run a knife blade or file around the inside lip of the fuel tank to
develope a slight bevel on the opening of the tank.  Sometimes the
hole is too small because of the flashing remaining when the tank is
molded.

Good luck.

OS

Well...

*I* use a small (1/8") screwdriver blade to push it in one small part at a
time being careful not to cut it since I will be depending on it to seal the
tank.

   I think that water just makes it stick all that much more.
   Try using a shot of spray silicone. That always works for me.

MJC

Hi David.

When I read your term of endearment, I just knew you were an Oz. :)

Mate, unless WM have changed their fuel tank or bung design or sourced
same elsewhere (Vietnam?) for the cheapie Sky Raider, you simply
shouldn't be having a problem unless induced by the proverbial "finger
trouble". ie: Don't take offence, but that you're putting together a
Sky Raider implies you might just be a newbie?

Can you fit just the bung alone without any of without the plates and
screw in place? If so, you just need to loosen the screw some more.

If not, on balance of probability there might just be a minor defect
in manufacture of the tank neck or a bit of flash obstructing the
bung. Have a look. You might have to remove the flash with the blade
of a hobby knife, of if the neck itself has a minor deformation,
attack it with a Dremel or round file. A lot quicker and more
practical than sourcing an exchange replacement unless the LHS has
another Sky Raider box in stock. If it's seriously deformed, just
return it to your LHS. WM offer a replacement parts warranty, and the
Oz distributor of WM, HobbyHQ are much more supportive of LHS customer
complaint than that opposition crew in Melbourne.

My recommended World Models bung insertion and testing technique.

1. Have the expansion screw as loose as possible, but still inserted
sufficiently as to just retain the inner plate.

2. Preferably using *rubber* grease, apply an ultra thin coat both to
the bung and to the tank neck.

3. Insert bung and tighten screw. Don't overtighten and distort bung.

NB: IME you have to finesse the tension a little better with WM bungs
due to the lack of a secondary fitted cap over the neck a la DuBro or
Sullivan units. However, *provided you tension the bung right*, the
std WM unit proves itself just a reliable in practical service IME.

4. Seal vents with silicon fuel tube and test tank in water filled
sink for leaks. If bubbles are seen, tighten bung screw some more with
incremental finesse until air stops leaking from tank.

If that doesn't work for you, then either the unit IS porked OOTB or
you should find another hobby.

Good luck. WM are the best ARFs in the marketplace today and their
hardware including tanks stands up to the in-service reliability test.
I appreciate the Sky Raiders are their budget priced offering, but I
couldn't see WM allowing their reputation to slip on what is
essentially a intro to the hobby model targeted at newbies.

I have found that a small hole in the fuel tank aft area on the bottom
with a short piece of brass inserted flush inside in said hole will help
drain the tank area quickly before it reaches the other parts aft. Tanks
will split when you least expect it. Epoxy the tank area too. I pressure
test tanks yearly .