mjderstine

Hey guys, this should be an easy one. I have a practically brand new OS 1.08 and dont know the best fuel tank size. I know it can play a role in the performance of the motor.

I was planning on a 16oz tank.

what are your suggestions?

w8ye

My Feedback: (16)

The 16 oz will be fine

mjderstine

thanks for the answer so quickly!

w8ye

My Feedback: (16)

Tank selection is sometimes confined by the size of the fuselage.

You could get by with a smaller tank but your flight time may be more limited.

Flight times for individuals vary because of flying styles

kenhiraihnl

i plan to use my 1.08fsr in a venusII, which comes with a 14oz tank...the review article in tower gave good rating for the 1.20ax and the stock tank...you might be concerned with fuel feed problems (tank position, muffler pressure, engine position, fuel lines, etc.)...i'll try to use the stock muffler, and keep the rpms high for adequate muffler pressure...btw, i have a giant ss w/ 1.60fx mounted 45-degree invert, 17x10apc, w/ stock muffler...starts on the first back flip, pulls like a horse, and taxi's back to the flightline every time...ken

Kweasel

My Feedback: (29)

The 108 has a big carb that makes fuel draw marginal. It may have difficulty at the top of uplines.

kenhiraihnl

a friend of mine is doing me a favor, and giving my 1.08fsr the antifreeze cleaning job...after that, i'll install new bearings, crank, conrod, wristpin, and a performance specialties abc piston/sleeve...hopefully, i'll be able to do multiple rolls on my uplines and downlines for spectacular humpty-bumps...lol...ken

mjderstine

i have no issue with fitting any particular fuel tank. i was concerned with having adequete fuel pressure with the correct size tank. the tank is only going to about 3 inches from the motor. with a maximum of 5 inches of fuel line.

kenhiraihnl

i think you'll have no problems with that setup...imho, muffler pressure is the key...one of my engines is an os.37szh, mounted on a 10 pound heli...the carb has a 10mm bore...despite having a main tank, header tank, and lots of fuel line, fuel flow is amazingly constant...the engine uses high nitro, runs at high rpm, and is set a little on the 'fat' side...once, the muffler pressure line had an air leak at the muffler nipple...the engine leaned and quit...with that kind of experience, i've never had to use a perry pump on my planks although using a pump might improve fuel flow even more...ken

Kweasel

My Feedback: (29)

Dont try to apply helicopter tuning specs to an airplane application unless you are using very small props. Heli carbs are too for the rpm most airplanes can use.

kenhiraihnl

great observation and advice!!! funny you mentioned that, though...a friend just gave me a nib jett sj50, which i'll be breaking-in tomorrow...according to the break-in instructions, jett already ran it at 17,000 briefly on a 10x6 master airscrew before shipping...now that's the rpm's i'm more used to hearing!...i'll stick it in an arf kaos40, which was going to be powered by a os.46sf converted to diesel, but i think the sj50 will make it a better 'sleeper'...i noticed that the motor mounting hole spacings of the .46 and sj50 were identical...sorry for hijacking this thread on fuel tanks...nice chatting with you guys...ken