jcaz72

After about 8 flights the metal backing of my Avistar's fuel tank became loose and flooded the whole front of the plane. I was flying with my instructor yesterday and none of us noticed the problem even when the engine had problems running and actually had 2 deadsticks landings. As soon as I arrived home I made a a detailed inspection of the plane and then I found the problem.

The firewall and the fuel tank's area were soaking wet. Is there any additional rework that I should do to that area (out of just drying it)?

Is it a common task to tighten the fuel tank metal backing frecuently? [:@]

CrashBurn69

My Feedback: (1)

I would just relace it with a Dubro or Sullivan tank. I think it was in the RC Review last month when they tested stock stoppers vs the other two. And they were suprised with the results. I replaced mine with the Dubro and have almost 30 flights on it with no problem. KNOCK ON WOOD!

hookedonrc

Crashnburn is right. I had the same thing happen to my Avistar. I see it happening over the Winter when the cold seems to shrink the plug and it begins to leak. Happened on two of my planes, and just tightening the stopper brought them back.

raideron

My Feedback: (1)

Sorry to hear of your tank problem!

I'm working on my 6th gal. of fuel on my Avistar with no problems
to date since 2/10... After about my 15th flight I did remove all from
the plane just for a look see.. All looked good and tank had no leaks.
At that time I did recoat the cowl and tank area.. Just incase..

I'm up too around a 10 second hover with the Avistar and LA 46
with an 11/6 prop.. If I can move the sticks right on the first move
I may be able to extend that time... Then.. doing it lower...

My flying time with the Avistar will be cut down now since I just was
given a .40 Dazzler/w tower .40 engine/reciever and servos and Dan
my trainer has ordered a crystal for my radio.. In exchange for me
watching his watering system while they leave this Arizona "HEAT"
for the summer... Man... Did I ever meet a GREAT trainer and
Friend!!! Oh, he also said I can use his shop and any parts/tools I
may need to finish my other project a 4*60:-) Then to top it all off
Dan tells me if none of the plants/trees die for the three months he
will be gone I get a FREE can of fuel for each month..
What a Friend and Great Guy!!

grumpE

My Feedback: (6)

I learned this the hard way too. Always check your tanks in the spring. Mine was a SuperStar 40. Was flying with an instructor and we noticed that the engine started to cough on climb out. Ran fine in level flight and then again got rough when I climbed. Evenutally died. We speculated that the pressure tube may have popped off. Walked over and everything "looked" fine. Picked it up and switched off. At this point I tipped the aircraft and fuel drips on my feet. Looked at my instructor and he said I really had better open her up and start pulling electronics. I asked why and he got that knowing dad-like look and said trust me.

Off comes the wing and sure enough there is almost a full tank of fuel sloshing around the bottom of the fuse.

This was my first day out of the spring and I store my planes in a garage in Nebraska. The plug had shrunka nd the threads on the retainer cap slipped ever so slightly.

Next leason learned. Always put your receiver and battery ina baggy before you wrapp them in foam. Luckily we discovered the problem before any of the electronics had a nitro/oil bath.

Happy to hear it was not a bad outcome and thanks for sharing with everyone. Made me think back over my experience.

GrumpE

a65l

My Feedback: (17)

Nice thing about the Avistar is Hobbico does a GREAT job fuel proofing the tank compt. and former. My Avistar's fuel tank is having a second life in my Spacewalker II, albeit with a Sullivan stopper! Avistar's stopper is in the Super Sport's tank, as I didn't really like the stopper World models included with the kit... I never even noticed the stopper screw getting loose, but I SLIGHTLY damaged the threads on the back of the stopper to give a sort of a "self locking" feature.

Andy

fourthearth

had the same problem with my 40T trainer plane. I didn't notice that the tank was leaking until before a flight I was checking my control surfaces and found that the ailerons were not working. After removing the wing and checking the connections (they started to work again) I put it back together and then found that the throttle wouldn't work. So I opened it up again and noticed this time that the foam on the receiver was soaked in fuel.

I ran a hair dryer on a very low power in the fuse for awhile and on the receiver, seems to have worked because everything is working great now. Patched the tank using a hot glue gun.

Dennis

SarDog

The fuel leak problem has happened to me twice. Didn't notice until I put the Avistar nose low and fuel dumped out. The second time I pulled the tank out I notice the the top seam had cracked. For those who have replaced the tank, did you have to do any modification to get the new replacement tanks in? Trying to figure out what to buy.

jcaz72

Went to fly this past Sunday and the engine of my Avistar start running unconsistently after months of not giving any problem... I was afraid engine would fail... I did not... just had some strange up and downs when going fm iddle to high on the throttle... as soon as I could I opened the plane and found AGAIN traces of fuel on the inside... 5 months after I started this thread it just happened again...

Well, I guess I deserve it... everybody said I should either tighten the backing screw frecuently or change fuel tank... I just did not do anything[]

Nas19320

I'm glad I got to read this thread because now I'll know to keep an eye out for any leaks. What other fuel tank will fit in this plane if I need to replace it? I looked at the Tower Hobbies site and the tank they say matches to the Avistar under comments it says "this tank will NOT work on the Avistar without modifications to the fuse." It looks the same as the stock tank, so what modifications are needed? Thanks.

jcaz72

Nas,

It took 5 months fm one leakage to other so I guess if I had followed the advice of tightening the stopper screw every once in a while this could never happen again. So even when I have been burn twice I will not change the fuel tank but rather tighten the screw once every 2 months at least...

You maybe need to know also that I am about to move out of this trainer (great trainer!) to a more advanced low wing aircraft, therefore my feelings towards the Avistar are not as strong as when just starting...

Montague

We just had an Avistar get filled with fuel last night. When we pulled the tank, the stopper was so loose it pratically fell out of the tank on it's own.

Crashem

If the Tank compartment was properly fuel proofed just drying it out should be fine. if you think that the fuel soaked into the wood try applying some baking powder to the area I tried this once at it seemed to "pull" some of the fuel out of the wood.

raideron

My Feedback: (1)

I never(to date) had a problem with my stock Avistar/planes fuel
tank or any other screw/linkage... Yes some did work loose etc.,
But I did re-tighten/check before the next day's flying... I made it
a habit to check all accessible screws/bolts/linkage after 1-2 days
flights, this along with preflight checks.. And on the screws that
was inaccessible, I would remove what ever needed to be removed
and check those items i.e. fuel tank stopper screw after about 5-6
flying sessions.. It will save you on those rare occasions, Not to
mention a safer platform.. And on the few ARF's that I put together,
I've added more epoxy to the firewall, painted the tank area, and
cutout/drilled a drain hole aft of the tank compartment to minimize
the spread of fuel and it's eaiser to see problems.. Our hobby put's
on our flying platforms, high stress...vibration and flex. So we need
to keep all in "check" best we can.. As with wiping your plane down
after each flying session work in a schedule to check fasteners etc...
........ Now watch.... Something we happen to me.. Now :-(..........

Chazon

Please forgive me for 1) dragging up an old post and 2) for being a newbie but . . .

How do I need to go about checking my tank and tightening the cap screw? I am new to the hobby and purchased my Avistar as an ARF. I've had about 8 flights with an instructor on it so far, but would really like to check this so I don't have the same problem. I'd also like to change one of my fuel lines so I have a different color leading to the engine for fueling purposes. Would I remove the engine or go through the top cavity to check the tank? Any help would be appreciated.

Chazon

Ugo Ferrari

My Feedback: (1)

You're gonna have to pull the tank out, tighten the cap screw, place the tank under water, (an old coffee can works here). Pinch one fuel line, and blow in the other to pressurize the tank. Check for air bubbles around the fuel tank neck. No bubbles? replace the tank . Don't forget to change the FUEL line to identify it ! Oh yeah. add that 1/4" drain hole to the bottom(under tank compartment) of the fuselage to see any leakage before it does any major damage.[]
By the way, Cat Litter does a great job of drying up a fuel leak !

Good luck !
Ugo