Help! More gas questions

[Space Bat]

Hi Joe/Jim....

I am getting back into engines/gassers and wonder if 3D flying there are different thought processes involved....

Am currently breaking in an engine...and currently have an idle just under 1600 but the engine has yet to fully break in and needs more work ...is this too low? - for 3D is it better to have a higher than normal idle?

Also with throwing a plane about - is the standard tank and clunk setup sufficient....or do you perhaps put two feeds in and 2 clunks to guarantee fuel pick up - or is this overkill?

I currently have a combined filter and clunk....but when fitted into a plane not sure thats the way to go - possibly better to put inline filters rather than a tank filter what do you guys recommend/use?

On the Carb I heard for 3d you should consider putting a fitting and run some tygon back from the metering plate hole to the tank??

Is there anything else I need to look at for a good reliable setup for a gasser performing 3D

Any help advice much appreciated...

 

[Joe's Dad]

We use a idle up switch. When performing 3d maneuvers we have the idle set higher. Only when we are coming in for a landing do we let the engine idle down. Controlled by a switch.

Tanks, I have never used a standard tank. I have always made my own. But there are some nice tanks out there and some really nice custom fittings from PSP MFG and Fox.
#1 If the clunk line does not stay in the end/bottom of the tank, you will have problems. I use a heavy duty Clunk from TowerHobbies, drill a 1/8" hole in it and solder in about 4" of solid brass tubing. Then about 2" of tygon up to the cap fitting. There is no way the clunk can get caught up front in the tank.
#2 We always have a good filter up close to the carb to catch anything that made it that far. The Combined Clunks and filters are okay, I just don't prefer them. And I have my reasons. But lots of people run them with no problems.
#3 Please don't run a line from the meter plate to inside the fuse. Just make sure the air has plenty of exit space from the engine area. You'll be fine.
#4 leave the spring on the throttle butterfly shaft. Use a good quality servo. The throttle servo gets more use than most people think.
#5 Zip tie all tubing connections. Inside the tank and outside the tank.
#6 Put a loop in the over flow line on the gas tank.
#7 Use a good oil and don't go over a 50:1 ratio.
#8 Tie stuff down and keep all gas lines away from the headers and mufflers.
#9 Read my gas engine tuning guide.

 

[Space Bat]

Many thanks Jim...much appreciated..

The servo is something I didn't appreciate and didn't figure in on getting better quality and spending more...but makes sense.

I will base my tuning on 1600 idle and try to get as much as I work in bigger props...I can then use the TX to put in a idle up to place it around 1800-2000 depending on what keeps the plane from rolling too much.

I guess the rest will be trial and error....its a long way from the circle flying I did with fuel setups...so pretty apprehensive on how it fairs doing 3d...

Much appreciated for your tips and advise...and I my first step was to read you tuning guide...

Now off to wake the neighbours with some more tinkering

Chris

 

[chadcan]

Where can I find the Jim Smith Gas Engine Tuning Guide?

 

[gyro]

Where can I find the Jim Smith Gas Engine Tuning Guide?

http://www.3drcforums.com/content.php?132-Carb-Tunning-101-for-Gas-engines