Don't Try This
 

After a flying session it's routine for me to disconnect the fuel line, put the lead on the plug and hit it with the starter to burn all residual fuel in the crankcase. I was out flying with my son this evening after 4 flights earlier in the day. Two additional flights then the ESV meter says it's time to stop so we start breaking things down for the night.

I announce I was going to pump the remaining fuel out of the tank then run the residual fuel out of the engine. My teenager says, "No, just run it dry now. I want to finish wiping off the plane." So I comply and disconnect the fuel line. I have a fuel filter between the tank and carb and disconnect the tank tube from the filter. Put the lead on and hit it with the starter. Engine fires up but with fuel still in the tank and the muffler pressure line still attached...

See where I'm going?

Sure enough, we start spraying fuel out unplugged line. But the engine doesn't lean out and die. Seems that all this excess fuel being sprayed out the line still attached to the tank is being sucked in by the line still attached to the carb. This is a gap of about 3/4" open air and the darned engine doesn't think anything is wrong - it just keeps running! My son is getting raw fuel and exhaust all over his hands and arms. So I say, "Now what?" There's still over ½ of a tank left.

My brain finally starts working again so I reached down and plugged the carb line with my finger which stops the flow of fuel across open air and the engine finally dies.

I think my son understands now why we empty the fuel tank before doing this. Also wouldn't hurt to disconnect the muffler pressure line.

Luckily all we had happen was a lot of raw fuel to clean off the plane. I wear eyeglasses so I have "some" protection against raw fuel getting into my eyes but my son does not.

Electrics are starting to look more inviting all the time. :)

RE: Don't Try This
 

seems like you learned a routine, so just stick with it. lucky nothing happened, don't get discuriged. just teach your son the right way(your way), and have him stick to it. it would be nice to see that young man grow up into the hobby. happy flying

RE: Don't Try This
 

I dunno. Try that with an electric plane and you'll have extra electrons leaking all over the place. And they're hard to clean up.:D Is it really worth the risk??

RE: Don't Try This
 

Bruce88123, why do i get the impression you are not particularly fond of electric powered aircraft? Don't worry , they are not my cup of tes either, i am a glow power man
Bill

RE: Don't Try This
 

Who me? Hey, electric is better than Vegemite.[:'(] HeHe:D

RE: Don't Try This
 

Nobody ever taught me to disconnect BOTH lines when draining the tank. Maybe that's wrong, but seems to me the air will get sucked in through the muffler, along with any residuals which will just gunk up your muffler.

And as far as electrics and human danger: I've read too many stories about accidentally bumping the throttle and turning the Tx on with the throttle not at zero, or reversed and causing bodily harm. At least with glow, you have to put in a little effort to start that saw.

Now having said all that, it's so cool that you have your son at the field with you. I'd give anything to have my 5-year old boy get the bug from his dad and want to fly RC. He loves airplanes, but at this point it's all combat flight simulator on the PC. I read so many posts from sons who's dads turned them onto this hobby. :DVery cool.

RE: Don't Try This
 

:D Yep, I saw where you were going. The best way to dry out the engine is to run it at full throttle and pinch the line closed then wait for it to die. The high revs will soon sweep out any fuel that's enough to actually fire and the run down to a stop sweeps out the remainder that's too lean for ignition. But learning from your experience, keep the fuel line pinched for a few seconds after the engine has stopped to allow the residual pressure in the tank to flow back through the muffler or it'll just push some fuel back into the carb. Then drain the tank.

RE: Don't Try This
 

When I'm finished flying for the day I open the throttle wide open, connect my fuel pump to the muffler line, put my thumb over the carb openning and crank my six shooter to draw fuel out, then release my thumb. The very small amount of fuel actually left in the crank case holds the lube to keep everything from rusting and all of the liquid fuel from the carb back is sucked into the tank. Then I pull of my fuel line from the carb and six shooter the leftovers back into my can. Its just as clean coming out as it was going in to the naked eye and I go though a can of fuel about every three weeks or so and haven't had a problem with contamination or anything. My EVO starts on the first flip by hand after priming every time.

RE: Don't Try This
 

True. I'm doing this hobby today because my dad bothered to take the time to "play" with me back when I was a young teen. I built and flew a McCoy 35 redhead powered Sterling Ringmaster for C/L then built and flew a Sterling Minnie Mambo R/C trainer on single channel and escapement power for the rudder back in the 1960's. I still build and fly C/L and R/C today. Belong to a C/L and R/C club as well. I lost my dad to cancer about 6 years ago. I really miss him.

I did a thread w/pictures nearly 2 years ago of my boy and I soloing our trainer - http://www.rcuniverse.com/forum/m_3477988/tm.htm and got some very nice replies.

Yeah, this hobby is cool but spending quality time with you kids is priceless.

RE: Don't Try This
 

Dad's are Cool!

My stepfather has built for 25 years and flew for the first 5. He gave me a plane last fall to start me off. Now he is out flying with me and his 10 year old grandson. We all had our planes out yesterday from 8:30 to 5:00. We burnt up about 3/4 of a gallon of glow fuel and now I am waiting for a call and off we go again.

As far as what happened with the fuel line. I don't run my engine dry. I use a 2 line setup to the fuel tank for filling and emtying. I fly at least once or twice a week so I don't feel it is necessary to run it dry. With the 2 line system I don't get anything in the fuel tank other than fuel. After emtying I use a small piece of brass fuel line and join the carb and exhaust lines together. Than if I stand it nose down fuel doesn't run out the carb.

Just me.

Del

RE: Don't Try This
 

When I'm done flying for the evening, I empty my fuel tank,(As Usual) then I put my thumb over the carb and prime the carb with the fuel I have left in the fuel line... connect the Glow Starter and start the engine. While keeping the Glow Starter on, I let the engine idle until it dies. (Runs out of Fuel)

Then I know I no longer have glow in the lines or engine.


Some people say we don't need to do that unless we don't plan to fly in a month or so. Personally, I do it anyway because it keeps our tank, fuel lines and engine clean. It's a good habit to have, I love my planes and I take good care of them so they last me for a long time. :D


Luftwaffe Oberst
Radio Aero Modelers Club
AMA District II
Pulaski, NY

RE: Don't Try This
 

The reason behind running the engine (particularly the crankcase) completely dry of any fuel is because methanol will suck any moisture out of the air until it reaches half methanol and half water. The water causes rust and then your bearings are shot.

RE: Don't Try This
 

Exactly! Well said. :D


Luftwaffe Oberst
Radio Aero Modelers Club
AMA District II
Pulaski, NY

RE: Don't Try This
 

i was going to mention water absorbtion un itl i read the last post but ill mention it anyway :D

as most know methanol in nitro fuel is hydroscopic - meaning that it will absorb water/moisture from the air, and this obviously not good for the engines bearings etc.

oh this water in engines thing reminds we of sumthing off topic but it has slight relvanc eto planes :) - in WWII the germans were running up to 50% water and 50% fuel in their planes for more performance. The water would boil in combustion and expand causing more pressure. but of course the engines were wornout easy, but hey it was war! this is also why your car might have a bit more "oomf" when you drive in the fog - added water content to the combustion....

well that was completly irrelivant but i couldnt help :eek:

RE: Don't Try This
 

I run my engines dry in the air and deadstick in everytime....Rog

RE: Don't Try This
 

Better you than us... especially a Scale Warbird. :eek:



Luftwaffe Oberst
Radio Aero Modelers Club
AMA District II
Pulaski, NY

RE: Don't Try This
 

Water injection
http://en.wikipedia.org/wiki/Water_injection_(engines)

RE: Don't Try This
 

Well truth be told I fly mostly 1/2a and most of my planes dont even have landing gear , but I do it with my .15 trainer too...Rog

RE: Don't Try This
 

It's funny you should say that because that's exactly what every control line plane does on every flight (barring crashes :)) and we never have a rust problem. There's a clue there somewhere :D.