Hi all, I'm relatively new to the glow side of things and am wondering if bubbleless clunks are a necessary item. My first glow installation is OS-52FS with the head of the engine is at the 7-8 oclock position. Thanks in advance guys.

I'm guessing you mean a felt clunk like those popular with the gas engine crowd? Not needed with your .52FS, balance the prop well and pack your tank in foam, should be good enough keep that fuel from foaming.

Mike

I don't use the bubbleless clunks on my glow engines but Saito and OS sell them.

7 or 8 O'Clock is fine.

Properly set up fuel system, they are not needed, something else you don't need to spend money on.

W8ye, forgive my ignorance but what does 7 or 8 O'Clock mean? Thanks in advance.

The engine is mounted at an angle with the cylinder "down". There are 12 hour positions on a clock. Standing in front of the plane looking rearward, the cylinder would be pointing at 7 or 8 O-clock. This is usually done to position the exhaust outlet at the very bottom of the plane.

As I'm s head scrolling down to read your answer and come across 7-8 O'Clock term, the light bulb flashes in my head what a nimrod moment I've had, brain far*! In June's edition of Fly RC, they had a timely article in their HOW TO section titled "Optimize Your Fuel System for Best Engine Performance". After thoroughly reading it over and over, I've determined I would benefit from the 3-line pressurized system. I be using conventional clunks in my system and would like to also like to thanks you guys for you input and help. If you feel I'm moving in the wrong direction please advise me, as I can never learn enough. Thanks again and be well.

I have used the OS bubbleless clunk in my pattern airplanes and consider them a neccesity. Now all of my sport planes have regular clunks and i have never used a bubbleless clunk in them. The OS clunk is about 15 bucks. what i usually do in my sport planes is take a dremel cut off wheel and grind another slot on the pick up. so it is an X not just the one slot.

Dennis

Unless your doing something fancy, a 2 line system works just fine. Keep it simple and it will run, don't make something more complex then it needs to be. A properly placed tank wrapped in foam will never let you down.

Dennis, thanks for your input, can you tell me what the purpose of the slot is to begin with and what your gaining by adding another.

Blue, if the clunk gets close to the end of the tank it can still get fuel through the slots. I've never seen slots that were small enough to need additional slots.

the slots are just 90 degrees apart just makes it easier in a low tank to gain fuel.

Dennis

Wow, what precision. I too read the article on the RC magazine using double clunks and a separate fill line. I could see no advantage except for the use of a check valve in the pressure line. That would ensure pressure stays in the tank at all times and ensures a positive feed - sort of a close circuit set up - no venting back through the muffler at low RPM states.

It sort of reminds me of the YS set up.

Cheers,

Chip

Chip, given the position of the head on my setup, would the three line system be just what the doctor ordered or is this then overkill. I don't want to overcomplicate things, however, I don't want do take shortcuts because its easier.
Thanks in advance.