barkin_bob

Doe's anyone know if the hayes fuel tank o-ring seal will work with gasoline? also, whats the best way to set up a tank for gasoline (venting) I'm thinking a one way check valve to allow air in . Also will the engine stop like a glow engine when the carb is closed off ? should I install a kill switch ? shure would would like all's input on this Thanks Bob

coony2787

My Feedback: (33)

As for setting up the tank i just run the vent line out the bottom of the fuse , preferably in a place that you can see fuel come out of it when your fueling so you'll know when the tank is full. You dont need any check vavle or anything.

Just set it up the same as your glow tank and run the vent out the bottom of the plane instead of to your muffler.

Unless your tank says in the instructions that came with for use with gasoline you will have to buy a conversion kit for it.


The engine will stop when the carb butterfly is shut all the way, however you still need another way to shut that thing down. I use a servo on the choke for this purpose this gives me 2 remote ways to stop the engine. You dont want to try and fly that thing out of gas if your throttle servo deciede to quit for some unseen reason. So yes you need a cut off of some sort other than the throttle servo!

Chad

Tall Paul

You MUST have an ignition kill switch. It should be both manually and remotely controllable.

coony2787

My Feedback: (33)

I dont know if you must have an ignition kill switch ? I think that either and or will work just fine! As long as you have 2 ways to remotely kill the eninge.




Chad

Stick Jammer

Nope, can't do that or you will never fill the tank. Just leave it open and dump it out the bottom somewhere. As mentioned above, the info supplied with the tank should tell you if it's compatible with gasoline. If it doesn't say so, don't use the rubber parts. I also agree that a Tx operated ignition kill switch is an option but not a must, just be sure you have two ways of shutting the engine down from the Tx. Your throttle servo is one, and I use a servo on the choke.

Tall Paul

I've the pile of junk not having an ignition kill switch created with a Ziroli P-38, when one motor stuck at 1/2 speed, and the other motor quit.
The throttling option is only second best to a guaranteed shutoff with a kill switch.

Stick Jammer

Really sorry to hear about that one, that does suck. With multiple problems working against you it definitely sounds as though that just wasn't your day. Did you have servos on the chokes? I can kill my gassers from the Tx with the throttle servo or the choke servo. If both of those fail I guess it was meant to be.

bentgear

Ignition Kill Switch = must have item.

Lets check the compression, BAM, oh s@#$ - help, anybody got any bandages?????????

or maybe

Kid comes walking thru pits. Nice big prop to flip. You later ..... Judge, that thing never has started on the first flip before in its life.

Simple to install and cheap, no reason not to have one.

Ed M.

coony2787

My Feedback: (33)

Well of course you have to have a switch on the outside of your plane to turn the ignition off on while it is in the pitts or strorage , but you dont have to have a remote ignition switch.

I think it would be common sense to have a switch on the battery! And while your at it go ahead and put one of those nice JR charge switch jacks so you have a convient place to charge.


Chad

Stick Jammer

If you are talking about a Tx operated kill switch I don't see your point.

bentgear

No, Stick Jammer, talking about a switch on the side of the plane to kill anything related to letting the engine run.

Ed M.

Stick Jammer

I believe part of this thread was in reference to methods of killing the engine from the Tx. I would think a manual battery switch for the ignition is common procedure.

Tall Paul

Wasn't my plane. MOF it was on it's first (and only) flight, when the throttle (servo?) jammed or disconnected with the motor at 1/2 power. When the 2nd motor quit, it went in.
The builder made up another one, and it too went in due to power asymmetry.
That was his 3rd in a row. The first one, a smaller version, dove in on its first (and only) flight.
P-38s are not good airplanes, either model or full-scale.
Were I to build a large gas twin, I'd have both the ground reachable ignition cutoffs on both motors, and the remote cutoff.
Scale twins are just nasty airplanes unless they're very carefully chosen.

Stick Jammer

Well, that depends on the skill and knowledge of the pilot but that's a whole 'nother thread. At any rate, the P-38 doesn't seem to be a good choice for that fella.

Mitty

Hiya Bob.
The ignition coil on your engine will have a wire ,single wire coming out.Thats the kill switch .If you groud it against the cylinder or any other part of engine(except carburetor) yoru engine will die.-thats an ignition kill.Possibilities are endless.You can rig the switch to the gear channel or just have a sitch outside the cowl.As for closing buterfly it will work as well.You can either close the butterfly or close the choke-both will kill.
Hows the weather in WA?

barkin_bob

Hey mitty got a kill switch on its way guess i will set it up to kill both ways seams to be the way. now to figure out the fuel tank system Seams to me if you leave the vent line dangling flying inverted will cause a serious fuel leak problem. Maybe I just don't see the picture yet.

chris77

My Feedback: (1)

hey bob i'm new to gas planes aswell, and i asked that same question and the answer i got was that the engine pulling fuel from the tank which would keeep a steady airflow into the air vent to displace the fuel being removed from the tank, they told me a little might come out, anyway sounded good to me.

Tall Paul

With a 2-line tank. one for fill-vent, the other to the motor, the motor drawing fuel sucks air into the tank via the fill-vent line. There can't any outflow with the motor running.
With a 3-line tank, 1 for fill, 1 for vent, 1 to the motor, the fill line tube inside the tank goes to the bottom of the tank. The vent line goes to the top. When fuel comes out the vent line while filling, the tank is full.
In flight, both fill and vent lines will supply air to replace the fuel the motor draws from the tank. Spilling out either line in flight is unlikely, and in any event, plugging off one or the other makes that impossible.

barkin_bob

I see the picture now Thanks all for the lesson.

Stick Jammer

How can you have a fill-vent line? If you use the vent line to fill the tank there is no way for the air to escape. The only way to have a two line system on a gasser is for one of the lines to be strictly a vent line. The second line is the fill line which must have a tee fitting, one side to the tank and the other side to the carb. A three line system doesn't need a tee. In either case the fill line must be plugged after the tank is filled.

mikeboyd

Okay guys, call me paranoid, but I still use two receivers on my big gas birds. If it is mag fired, I use the Great Planes switch unit. it has two switches in series. If either is opened, the engine dies. One mounts to the side of the plane for manual use, the other gets connected to a mini or micro servo for transmitter electrical kill. I usually use the retract channel on my computer radio to set it up on the spring loaded trainer switch, and plug it in the left receiver. The right receiver powers the throttle servo and the throttle kill percentage rate is set for the same sping loaded switch on the transmitter. Now, if I have a battery or switch failure on either receiver system, I still can kill the engine. A big gas plane can do allot of damage if it becomes uncontrollable, so being a former safety engineer, I get a little carried away. But better safe than sorry.

Stick Jammer

Two batteries and two switches into a single receiver will do the same thing.

mikeboyd

Okay, but what about the bus current through the receiver to those 8-8611's?