DLE 20 throttle problem

[my1stflight]

I have just installed my new DLE 20 in my Extra 300. I have a full range on the throttle servo but when I start the plane it seems to hit full throttle when the servo is at half throttle. I am unsure what is causing this, as when I take the cowl off and look at the travel on the throttle arm it moves properly.

[Bdegan]

This is quite normal with gassers.
They reach full power before the throttle butterfly is fully open.
So it often feels like the last 1/4 to 1/2 of the throttle stick movement makes no change in the rpm.
What most people do is go into the servo travel function. Run the engine at full throttle, then start lowering the servo travel at full throttle.
Do this until you here the motor rpm drop slightly.
Now start adjusting back up and stop when you here full throtle.
It make take a couple of times going back and forth.

This should now give you full throttle stick movement, with full throttle comeing as the throttle stick reaches the top, not in the middle.

[luv2flyrc]

As Brad says, this is normal. If your radio supports a THROTTLE CURVE, you can use it to create a curve that makes your throttle response linear to your throttle stick.

Mike

[kip51035]

When you load the engine down with a larger than normal prop, it limits the RPM the engine will turn. The engine at that RPM will only suck so much air. Therefore your engine runs out of suction at a little over half throttle. It is like driving your car up a steep grade in high gear. No matter how hard you press on the gas it will only go so fast. Try a smaller prop or less pitch.

[my1stflight]

I am using a 16x8 prop which is the middle of the prop range for this motor. It is also recommended by many people to use the 17X8 prop, but I can not due to clearance issues.

[kip51035]

What RPM are you getting? is it the same as the other people with this engine. Look in the intake and make sure that the throttle butterfly is going wide open. Adjust the main jet for optimum performance, than richen it a little to protect the new engine. Check for loose parts and contamination at the pickup. Check for a cracked carb spacer. I found one where the spacer was in backwards and the pump would not work. Make sure that the pressure bleed port from the engine through the spacer and into the carb is not blocked. If this all checks out I would suspect the the automatic advance in the ignition module is not working. Find one you can borrow and see if it makes a difference. It is possible that the pump in the carb is not working properly yet. Try pressurizing it with your refueling pump. Try a new plug. Thats all, the bin is empty, if it does not work now you got me.

[Bdegan]

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[MikeCam]

Completely normal for a gas engine, your pretty much at full RPM at 3/4 carb opening, the last little bit of opening will not make a difference. As long as your pulling the RPM's your expecting then NOTHING is wrong with the engine.

I use expo on the throttle, set throttle to half stick and dial in expo with engine running (could be + or - depending on set up) to get the engine to run at half throttle at half stick. Easiest way to make a curve.

Also, don't run it rich, set the high speed on the rich side of peak. It's not a glow engine.

[jc30955]

Also as a side not to MikeCam, "also, don't run it rich" if you do there is going to be a lot of carbon build up till the point at which the motor won't even start again. this happened to me and i disassembled the motor and found about an 1/8" of carbon on the crankcase head. I am also going to try a different oil and go with lawn boy.

[Dennis Pedersen]

Here is what you do with the gasser helicopters to make a more linear feeling throttle by making the linkage none linear.I would sure think it would help with throttle managment hovering ect.Hope this link helps you out some.

http://www.helifreak.com/showthread.php?t=154844

[atc666]

When setting your throttle curve up use a tach and measure your idle rpm and full throttle rpm.

With the throttle stick at half throttle the engine should be spinning at:

Idle RPM+(Full Throttle RPM-Idle RPM)/2

Keep adjusting the curve until you have the proper rpm at half throttle.

This will give the most linear feel across the range of the stick movement.