Seat Tank Vacuum?

[Screw]

Screw-In

After my 60 mile x-country home I filled the seat tank with what I had left. Didn't even get it half full. Sunday (a weeks later), I got more fuel and went to wash "DaScrew-Driver" and noticed that just below the upper seat tank support was sucked in like a kid eating lemon drops.

I relieved the pressure thinking it would pop back into place, but it didn't. I filled the tank and put the cap back on, and I'm currently waiting for someone to tell me what to do?

It may have bent the upper tank support and I don't know if I should unbolt it to see if it'll go back into shape.

Oh Great Gyro Gods, please speak and set me free from this worry. :D

Screw-Out

[GyroRon]

Sounds like your vented cap isn't venting. That would be bad news if it happened while flying. My advise to make darn sure you fix the problem with the cap, and fill the tank and park the gyro in the sun to let the tank warm up and hopefully reshape itself.

[Chuck Irby]

My tank has a vent hole in it just under and behind the cap.

[GyroRon]

The Brock tanks use a vented cap only. The converted dune buggy seats on our Dominators use a vent hole in the back of the tank up at the top.

[Screw]

Screw-In

Well, I don't know if I need another seat tank or not. I cranked up the air compressor and shot some air in the tank. Of course I had a full tank of gas too. The seat expanded and the bottom of the seat started to get out of shape so I quit.

I think all is ok the way it is, but that area that is sucked in at the brackett is really pissing me off. I'll probably have to unbolt the seat from the top support and drain the tank. The try the air think again.

Or I'll leave it alone until after ROC.

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[automan1223]

John,

I dont want to sound condensending but we covered this IN DETAIL about TANKS BEING VENTED. DO YOU HAVE A DEATH WISH ?

Dont go getting pissed off at me but your little fuel pump cannot pump from a sealed container.

Whos gyrobee had the tank problem ?
Go back and re read that thread. PLEASE....

2. Have the tank half full. Get an old towel cover the lower part of the tank with it. Roll the seat into the 11 am sun set it so it can get hot. In about 1 hour it will be extra hot and SOFT. Hopefully the vapor pressure will come up and the plastic with be like taffy. when it is back into shape, it has a " memory" pop the cap to release the pressure. Roll it back into the shade and let the tank cool slowly.

YOU WILL put a tank gromet and fitting with a separate vent hose at the top of the tank run a tube up the mast.
Make sure you dont overfill the tank because when you sit on it the seat will compress and spit fuel up out of the vent hose.

Who else can I yell at ? Who looked at your gyro and did not spot this ?

Scott Essex ...Did you have a vent on your tank ?

Looking forward to ROC !

Jonathan

[scottessex]

YES I did! Had a 1/4" hole right in the top of the cap. But I am changing to a seat tank.

Hey john, could you get your cap tested at an emisions inspection station? just for the sake of knowing it's the cap.

[GyroRon]

Johns tank is a standard Brock seat tank, just like the ones on about 75 percent of all the gyros out there flying. It uses a VENTED cap. I believe the cap failed. I talked to John on the phone on how to fix it, so he knows what he needs to do. He needs to vent it just like Automan1223 suggested, but it would be even easier cause the type of cap Johns tank has already has a nipple on the top of it for a vent hose. He just needs to modify the inner part of the cap to make sure the vent nipple will always be able to vent. Drain the tank partway and park the gyro out in the hot sun, that might help reshape the tank.

[Aussie_Paul]

John, a heat gun used carefully can help control the softer areas to manipulate back into shape.

Aussie Paul.:)

[jawbrey]

I have used a heat gun to reform a plastic tank with good results heat control is very good james

[Screw]

Screw-In

I drilled the cap to ensure venting. Don't think sitting it out in the sun will help at this point because the cap is very vented now. I aslo think the bracket being bolted to the mast is preventing it from popping back into shape.

I would never get pissed at you Johnathan. Your always a big help. No! I don't want to die. I see you at ROC. I just don't know if I can fix it by then.

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[automan1223]

I bought a new tiny electric air compressor last month for use at the home. I have used it to pump up tires maybe 3 times. This past weekend I fired it up but no pressure was building in the tank, the motor sounded funny. I cursed it then decided to pull off the air filter. I could not. I shut it off and it came off. There was a hole in the air cleaner housing that got plugged up good with a mud wasp gook. The compressor had no air to suck. The other vent on the housing had spider web material closing off the air vents. I pulled the air filter and housing had to blow them all out. I was amazed how much gook got in the new unit.

I would have 2 vents on my fuel system. 1 on the cap, one on the top of the tank. Look out for mother nature.

[Screw]

Screw-In

I think I fixed it! I took the day off from work to fix my gas tank and get more fuel.

No Fuel? Went to Home Depot to get 3 maybe 4 more 5 gal gas can. They had none. Sent them all to Fl. Oh well. I'll just have to live with what I have.

About the tank itself. As suspected I had to unbolt it from the upper motor mount and with a little air she popped right back into place. Now the upper seat mount doesn't fit under or over the upper motor mount. I unbolted the seat tank and the bottom and raised it above the motor mount and bolted it back down, and then tightened the bottom again. I think all is well.

As you can see from the photo, the upper seat tank mount was bolted under the upper motor mount. Now, the upper seat tank mount is bolted over the upper motor mount. I did have to move the upper motor mount down about 1/4 inch to make it work and all seems ok.

I'm ready for ROC provided the hanger survives these hurricanes.

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