STG

My Feedback: (26)

I would like to hear from IMAC people as they fly the long slow down lines. Please add any words of wisdom. Thanks

krayzc-RCU

My Feedback: (31)

gas or glow?

at idle u use so little gas that i have never seen or had a fuel issue with long down lines u can put the plane at idle and disconnect the gas line to test this theory. should run for over a minute @ idle with just what is in the line.

STG

My Feedback: (26)

I agree. For both gas and glow I have been keeping clunk at back of tank. Never had a problem with a down line until now. My gas run is short, though, and I am only running a 10oz tank--flexible black silicone line and a filtered clunk. I was thinking about tilting the tank up to time how long it runs at idle this way and how it handles air bubbles in the gas line.

See here for more details: http://www.rcuniverse.com/forum/m_58...tm.htm#5815365

STG

My Feedback: (26)

Can't believe 21 hits and only 3 votes. People must be thinking this is a stupid question.[&:]

krayzc-RCU

My Feedback: (31)

people are looking & maybe do not know the answer so that are not voting....

did u run into a deadstick?

STG

My Feedback: (26)

Yes, in a down line with motor in high idle (about 2,300 on the ground) my motor goes quiet (like it is not firing?) as RPM increases & engine is being turned over against compression by the prop(Down line breaking). I was a bit concerned that the motor was going to quit and about 10 down lines later it did.

I am trying to understand what is happening with fuel mixture on a walbro carb when this wind milling happens at a low idle setting. Could this cause the mixture to go too lean and & motor to quit?

Motor is a B46 and prop is a Xoar 20x8 on an E.F. 74" yak. It is 12.75pounds on take off.

krayzc-RCU

My Feedback: (31)

i would def look at the carb to see if you are lean on the low end along with looking to see the spark plug color. how is the transistion in the air any other mssing or bogging while moving the stick (thorttle)?

STG

My Feedback: (26)

Other than sounding like it goes dead on a full down line when braking(and finally quitting then), it runs great. A 45° down line or a long elevator the motor sounds and acts fine. My throttle pick up at the end of down line was always very gentle.

The Down line braking is very good with the Xoar 20x8 on this 12 pound plane. My guess is that I could go with a prop that does not brake as well and the problem would go away.

krayzc-RCU

My Feedback: (31)

Hopefully someone will chime in here to help us out with this issue. I run most of my high idles about 1800 and my motors never quit on down line and I am the type of flying that does a lot of down line I do the on both end of the field with center moves being stuff like slow rolls or loops and long down line doing 1/2/4/8 pt rolls on the down line. For a motor to die at that RPM is strange as we both know. What is your normal idle RPM?

What I was referring to is how does the motor transition on the ground from low to full any missing or burbling?

STG

My Feedback: (26)

Low Idle is 1,700. I set high at 2,300 for flying.


Motor meters fuel very well. Only slight burbling at low(1/4 throttle) power. I 3D about 1/2 the time and fly IMAC 1/2 the time. I am very happy with the way the motor is metering fuel as my throttle stick is continually on the move.

STG

My Feedback: (26)

Now 100 hits and only 8 votes. Looks like 1 out of 8(voting) are plumbing to have clunk fall forward.[&:]

3dd

My Feedback: (6)

plumb it the regular way and make sure you have about 3 clicks on high idle and it shouldn't ever quit running on your down line

STG

My Feedback: (26)

About what RPM do you think your 3 clicks of high idle is?