1
$\begingroup$


I am using a RC Fuel tank which looks like:
enter image description here

Is there anything special about the cap? The problem is I opened the cap. Should it never be opened? There are a few drops that leak in intervals when I put it back from the circled region.
enter image description here

Should I buy a new one? Or should I just tighten the cap hard enough or put some seal on the lid?

EDIT1: On a website selling the fuel tank the following is stated: "High quality and durable shatter proof tank of 1000ml. This fuel tank has 3 openings. One for fuel, another for fuel refill and another for compression from muffler." What is meant by "for compression from muffler"?

Thanks

$\endgroup$

1 Answer 1

3
$\begingroup$

My experience with glow engine models is that the tanks are made to be opened and resealed; the user needs to be able to replace the tubing inside the tank (which deteriorates over time due to methanol and nitromethane exposure) as well as in some cases change the length of the flexible "clunk" pickup tube to optimize for tank position and type of flight regime (trainer, sport, aerobatic, or pattern?).

Additionally, this appears to be a metal cap, so it should be capable of handling enough tightening torque to slightly compress whatever seal is inside the cap. When the tank pressurizes (assuming you're running pressure), the tank pressure will slightly push the cap away from the tank body; there needs to be enough compression on the seal to stay sealed in this state.

Prompted by comments and the edited question: tank pressure, also sometimes broken down to "muffler pressure" or "crankcase pressure" is a method of pressurizing a model fuel tank to ensure high G maneuvers (tight loops, for instance) don't starve the engine for fuel exactly when you need power the most. By pressurizing the tank (typically to only 0.1 bar or so) the tank pressure can force fuel up some distance, even against, say, 20 G. For trainers, it's unneeded; for most sport aircraft, very optional, but for aerobatic or pattern flying it's almost a necessity (last time I flew a lot, pattern models were starting to use actual fuel pumps for this).

$\endgroup$
3
  • $\begingroup$ Hey, thanks! Yes, It's a metal cap. I am going to put liquid fuel in it. By pressure, I believe you were talking about gaseous fuel? What do you mean by "running pressure"? $\endgroup$
    – Atharva
    Jun 28, 2022 at 3:35
  • $\begingroup$ Hey, I have also added an EDIT. Please have a look. Thanks! $\endgroup$
    – Atharva
    Jun 28, 2022 at 4:13
  • $\begingroup$ Whatever seal is inside the cap. This seal may have deteriorated as well, and is no longer seating correctly. The seal may have also fallen out and gone unnoticed. Note teflon tape is a bad idea in this case $\endgroup$ Jul 18, 2022 at 16:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.