Frag

I've been brainstorming on the best way to set up a fuleing sytem for my inverted Saito 1.80. The tank right now is mounted about 1/4 inch higher than the spray bar. I could use a smaller tank and get it lower but I want to use a bigger tank for this guzzler. This may be bad because of potential flooding...so, I was thinking why not use a one way valve between the tank and the carb with the flow limited from coming back into the tank. Why would this help? If you've ever used a one way valve you know that you can blow air though it only one way. And, when you blow it isn't really easy to get the valve to open initially. Once the valve opens though it seems to stay open pretty easily. So, after filling the tank you would not have the flow of fuel into the carb with flooding because the valve would prevent it (hasn't been forced open yet). But once you go to start the engine the pressure from the exhaust in the tank would force open the one way valve for your fuel to start flowing to the carb. Anybody ever try this? What do you think?

smokingcrater

most of the one ways i've dealt with open VERY easily, any small vibration would be enough to open it up, so just moving the plane would do it. it probably wouldn't be enough to hold back fuel, especially since it is well lubricated anyway.

how about a fueling valve higher then the tank. when you are on the ground, just open the fueling valve/insert probe (depending on type).

jaka

Hi!
Why don't you just lower the tank?
Regards!
Jan K

khodges

My Feedback: (1)

Just put a fuel regulator in the line. It's small, mounts on the firewall, only allows fuel to flow when the engine is running. They're designed for instances where the tank can't be mounted optimally. It will allow muffler pressure to build a little in the tank, feeds the engine as much as it requires, regardles of tank height or engine mounting angle.

Frag

Thanks for the replies-

smokingcrater, it may be the case that once lubed by the fuel it would open or seep too easily to hold the fuel back, but this valve as new is quite difficult to blow air through. I can hardly do it by mouth...I am trying to avoid using a fueling valve because I'm trying to keep the fuel lines at least 5/32 ID size from the tank to the carb. I haven't seen a fueling valve that is that big. I may have to resort to this in the end though


jaka, I can use the smaller tank and mount it lower as stated in my original post, but am trying to use this larger tank because the 1.80 Saito is known to suck up fuel quickly


khodges, your idea sounds good. Who makes them, where do I get more info? I don't want any kind of restriction in fuel getting to the engine when needed. I did a search for fuel regulator for rc on google and could only come up with a page on YS engines and how it uses a built in fuel regulator or something like it..


By the way this is for a TT Rare Bear ARF in case you guys were wondering....

Thanks again for the input-

BillS

Frag,

When I run into the ‘needs more fuel situation’ I simply use two tanks and mount the header tank in the correct relationship to the spray bar.

Information exists in the twins’ forum at:
Four Engines-One Fuel Tank Done
The wing is shown in my post is for an airplane that has five tanks.

Hope the information is helpful.

Bill

smokingcrater

it was just covered in a different thread, but a header tank at the correct height won't make a difference, or very little if any. the fuel system is sealed, so it doesn't matter if you have a header tank a foot above the engine, all that matters is where the center of the fuel mass is. (mounting it a foot above would change the center quite a bit, but mounting it inline with the engine won't)

if it IS making a difference for you, then you have an air leak somewhere...

BillS

Huh? I believe what was said was to “mount the header tank in the correct relationship to the spray bar.”

In a parallel two-tank system, a foot above header tank will drain all the remaining fuel in the header when the feeder tank becomes empty and would be a bad idea.

By the way the wing picture was taken upside down to show the tanks and the center tanks fit inside the fuselage when the wing is mounted. The tanks are mounted on the bottom of the wing to avoid connecting fuel lines during wing assembly.

Don’t have a clue what prompted the comment.

Bill