To avoid disaster... check your fuel tank seal regularly!
 

I just went out to fly my Avistar today (first time since last summer) , it was perfect outside (minnesota weather) 73 degrees out, and NO WIND!. I did my usual pre-flight checks, and everything seemed to be in order, except it seemed like it took an unusually long time to fill my tank, although at the time I thought nothing of it. But when I started up the engine, something was wrong. The engine bogged a lot even after needle tuning, and there was a little air bubble in the fuel like occasionally. Finally, after some more tweaking, and a new plug my engine was running well. I start down the runway noticing that it was handling oddly. I pull back on the stick after i had sufficient speed, and it climbed out... like a dog... For a second. It suddenly dove down, and i only had enough radio control to slightly pull up just before slamming into a curb. When i brought it back to my "pit" i took off the wing to see why my elevator was acting up. To my surprise, when i looked inside, the plane was full of fuel, and there was smoke coming from my elev. servo. I unplugged the battery as fast as i could, took out the radio tray, sucked the tank dry, and dumped it out. I had a towel and dried it as much as I could. Problem? The screw-type fuel tank seal had come out completely! It then dawned on me why it took so long to fill the tank... i was filling the whole plane! I am still drying and cleaning, and havent yet assessed the damage. Hopefully my radio gear will still work!

Total structural damage besides the fuel damage: a puncture in the wing coating, bent nose-gear, demolished prop, various scuffs and scraped to coating, and my vertical tail-fin snapped off. not too bad i suppose, considering...

RE: To avoid disaster... check your fuel tank seal regularly!
 

that is... especially if you have one that can loosen easily, such as this one with screws tight.

RE: To avoid disaster... check your fuel tank seal regularly!
 

Same exact thing happened to me recently with my Super Sportster ARF. Luckily, the rubber stopper sticks out through a hole in the firewall into the engine compartment. The fuel all dumped out into the engine compartment in front of the firewall. I was about 60 feet up and upright when it dead-sticked. I brought it in without any problems and there was no fuel-soaked wood. I've since replaced the stock Great Planes tank with a Hayes.

Jesse

RE: To avoid disaster... check your fuel tank seal regularly!
 

Dan, many of us have been there. This has been a regular topic on RCU. There have been many post about not using stock tanks that come with ARF's. I had the same thing happen when I first started flying though I had to have it happen twice before I realized there must be an issue here with stock tanks. I now use Dubro, Hayes or Sullivan and have never had a problem since. I honestly like the stopper set-up on the Sullivan tanks the best. IMHO.

Use KR-2 spot lifter to get the fuel reside out of the wood. It's a messy job, but this is about the best thing you can use after a spill. Let the KR-2 dry and then brush and vacuum out. Check your electronics closely to make sure no fuel got into the Rx. If it did you should send it back to the mfg. to have them check it out.

Once you have the fuel cleaned up and the airplane dried out check your glue joints to make sure the fuel didn't weaken. Add some epoxy where you have concerns. Just in case you are wondering, it will happen again if you use stock tanks. ;)

RE: To avoid disaster... check your fuel tank seal regularly!
 

I had that happen to me many years ago. Hayes tanks are now retrofitted in everything I own. I'll throw away the fuel tanks that come with any ARF. I used to have fuel tank related premature landings, headaches, and nightmares. I developed an allergic reaction to rubber stoppers. Now I install the tank and forget about it and have no problems. I just wish Hayes made a tank bigger than 16 ounces.

RE: To avoid disaster... check your fuel tank seal regularly!
 

For larger tanks try Tettra, great tanks with a metal ring clamp around stopper.
Very popular with pattern fliers , won't burst under presure , has small bubble at
top so fuel filler vents can go all the way to top and tank fills all the way. Got mine
from Central Hobbies , but I'm sure other places have them.

tommy s

RE: To avoid disaster... check your fuel tank seal regularly!
 

Exact same problem here (loose stopper) on my first Avistar flight for the year. I first noticed a problem when the aircraft pitched up sharply when I increased power in flight (fuel sloshing back in the cabin, I later concluded). I decided I had better bring it in to see if the wing bolts (recent mod) were loose or something, and it deadsticked during approach. Landed fine.

Everything seemed okay in terms of controls, wing, etc, so I started to fuel her up again.. I got suspicious when after a 3-minute flight it took the normal length of time to fill the tank again, then gasped in horror when I saw fuel dripping down through the landing-gear mount point. No smoking servos, but it was a big mess in there. Given what fuel does to balsa/glue the plane's days are probably numbered... You cant fuelproof the ENTIRE inside of the plane, and when that much fuel is washing around it gets everywhere!

-Greg

RE: To avoid disaster... check your fuel tank seal regularly!
 

I just took my UCANDO3D out for the firs time tis year last weekend and had a perfect flight. No problems at all. After the flight I noticed that it was real wet under the cowl. I have a Saito 100 in my 60 size one and the Saito has a vent nipple ont he crak case so I figured it must have had excess oil in the the engine. I got to looking and it couldn't have had that much. Turns out my tank leaked around the stopper and got the inside of the fuse wet a little and luckily most just got the engine and cowl wet inside. Easily cleaned up. The stopper shrunk back since the end of November and it is teh stock GP tank. The stopper was a loose and I had it tight. Very tight.

Always check things like this if it has si up a while. It pays too. a lot less work to pull the tank then to pull the tank and clean everythign up and I was luck not to have a fuse full of fuel. Balsa and fuel just love each other[:-]

Scooter Ross
Robbe-Schluter Field Rep.
Minicopter Factory Field Rep.

RE: To avoid disaster... check your fuel tank seal regularly!
 

Nothing new, I've been there.

When I assemble a new tank, the last thing I do is to run a bead of " Zap Goo" all purpose adhesive and sealant around the stopper to seal it against the tank. Works for me.

RE: To avoid disaster... check your fuel tank seal regularly!
 

ALL my tanks are glued to the backside of the fire wall with silicone caulk and the stopper stuck through a hole in the firewall. If the stopper comes out or starts to leak the only thing that gets fuel soaked is the engine compartment. I broke this rule once and paid for it with a soaked fuselage on a brand new plane. 'Nuff said!!

RE: To avoid disaster... check your fuel tank seal regularly!
 

make sure its tight.. ive never had a prob;)

Mettler1
 

I mount my float plane tanks the same way to keep out water.

RE: Mettler1
 

Same EXACT problem here on 2nd flight of the Avistar for the new season. Acted like it was tail heavy at first, then would act like it was nose heavy. Repaired tank, only to find out the SAME thing happened to my H9 CAP after the first flight of the new season. Must be something that happens to the rubber seal when it sits for a long period of time.

funflyer50
 

The rubber stopper "relaxes" over time loosing it's elasticity.
I had one come out completely in a combat plane.

RE: funflyer50
 

This is amazing how common this is. I had the same thing happen with my UCD last weekend. First time out this year and the stopper popped. In all of my years flying I never had a single fuel tank/stopper related problem and I guess I took it for granted. I didn't bother to check the fuel tank as part of my pre flight. I definately will from now on.

RE: To avoid disaster... check your fuel tank seal regularly!
 

Can I join the stopper poper club.:):) I had my Spectrum out for the first time this year this past weekend and I went to fill it up and I stopped when I saw the fuel pouring out of the front of the fuse. Luckily I had the stopper through the fire wall and sealed with foam tape. My stopper did not come out, it was cracked so bad it was in 4 pieces so there was no way it could seal.

With the Spectrum I need a round long fuel tank so I will just get a new Sulivan stopper and put it back in. The stock stopper material looks like it turned from rubber to hard plastic.

Dru.

RE: To avoid disaster... check your fuel tank seal regularly!
 

after assembling the tank. scuff up the area around the stopper and the stopper itself and apply "GOOP" sealant around and on the stopper. Tanks will now go several seasons before you have stopper problems, Works equally well with gas and glow. Being doing that for many years on boats using high nitro fuels and all my planes and no stopper problems since.

zonk

RE: To avoid disaster... check your fuel tank seal regularly!
 

I'm running my UCD with a Tower Hobbies 75. My problem is that every time I fill the tank it floods the engine, I can see drops of fuel coming from the carburetor. I was told that the fuel tank was too high but everything was installed as per instructions, there's no much space for improvisation or changes here. Any suggestions?

RE: To avoid disaster... check your fuel tank seal regularly!
 

[&o]I'll weigh in on this!

I had the fuel pump humming along for what seemed like a longer amount of time than usual........ I was filling my Great Planes Pitts ARF and gasoline started to pour out from the leading edge of the bottom wing. When I took the wings off the fuse and pulled the supplied tank I found that the stopper had literally "shrunk" and was loose in the tank. This was one of the Dubro stoppers that was reddish brown in color. I called Dubro and they helped me identify it as one of their own. (Dubro Gas Stoppers are reddish brown in color and have a letter "o" embossed in the front side.) The man told me he had never had a problem with his stoppers doing that but I told him I would return it to him so he could see it for himself what had happened. I definently know it was a Dubro because I had the old package still in my box, the "o" was still legible and I personally retro-fitted the tank because I was going to run a G-45 gasser in the Pitts. Now I am scared to trust any stopper but will look into a metal cap plus some silicone to go along with the stopper to do the job a stopper is supposed to do! Not bashing anyone's product but I don't want to fuel my front end of my plane any more than I have to!! (BTW... the stopper was only in the tank for a couple of months.)
Terry

RE: To avoid disaster... check your fuel tank seal regularly!
 

Roger, I just found this thread. You referred to KR-2 (maybe K2R), where do you find it? I used to find it here at the Publix Supermarkets but they stopped carring it. I have looked all over town without luck. That is one of the best products I have used. It will suck fuel and oil from very badly soaked balsa wood.

RE: To avoid disaster... check your fuel tank seal regularly!
 

K2R works great and was very hard for me to find. I also found a product called Abzorbit that is a fine powder made for soaking up liquids. Sprinkle it in the fuselage and let it set a while. Vacuum or blow it out after it does its thing. Repeat as needed. Learned this after the stopper came loose in my Ultra Stick 40.

RE: To avoid disaster... check your fuel tank seal regularly!
 

Flylow,

Abzorbit, I have to look for it. Anyone out there has any ideas where to find it in South Florida?

RE: To avoid disaster... check your fuel tank seal regularly!
 

Vicarh,
Check Lowes. The Abzorbit website says Lowes still carries it. It comes in a gallon size plastic bottle. Seems like it was less than $10.