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Change in idle today..
Maybe Im going nuts, But I don't think so. I noticed that while taxiing and doing brake tests today, At about 1/4 fuel left the idle increased slightly. Barely noticable but the plane would not stop without the brakes. Only thing different about todays run was the turbine oil percentage. I used 2.5% instead of 4-5% like the last batch, Something tells me that's not the cause. Any suspects come to ind? Anything I should check on the data terminal?
Thanks! Pete |
RE: Change in idle today..
the ECU is the only thing that can cause an increase in RPM like that and typically that's because of an input from the TX. at XXX stick position on the TX the receiver gives XXX pulse to the ECU and the ECU knows that's idle and it'll lower/raise the pump voltage to keep the RPM at the set idle RPM.
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RE: Change in idle today..
Pete,
What engine are you using? |
RE: Change in idle today..
he's a jet central owner i do believe there Harley
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RE: Change in idle today..
I have a JC falcon. I mean the change was so small Im not worried just curious. I dont know why something like this would happen during the run as opposed to the whole time.
Thanks! Pete |
RE: Change in idle today..
I'd guess your wheels/brakes got warmed up and looser is why you noticed the rolling more. you can plug in the data terminal and watch the RPM
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RE: Change in idle today..
ORIGINAL: KC36330 I'd guess your wheels/brakes got warmed up and looser is why you noticed the rolling more. you can plug in the data terminal and watch the RPM Pete |
RE: Change in idle today..
Could it just be the weight? If you have 25% of fuel left, the plane is significantly lighter than before a flight.
Arnaud |
RE: Change in idle today..
Ok weird, It wasn't my imagination, The HDT says user off idle was 40k for the last data available. The falcon is supposed to idle at 32k.
Pete |
RE: Change in idle today..
Pete, I have noticed your increased posting here and your questions are very good ones so please don't take this the wrong way. Are there any regular turbine guys in your area?
There are a lot of real experts here on RCU, and really two of the more trusted in my opinion have even posted in this thread. But I fear as your big day approaches you might be saturated from differing opinions here. I would sincerly suggest if there are local turbine guys to you that you have them go through your airplane and give you a hand on your big day. OK, off my soapbox. I have had a couple of falcons and they can from time to time make a revving sound. Because I've heard about 10,000 turbine runs, I'm usually looking to hear something more sinister than idle changes before I'm giving up on some flying action. There are some here that might remind me of my first big day "Is that Normal" [sm=bananahead.gif] ???? You're in good company, but again, nothing was more helpful to me than digesting what those in my local area were helping me accomplish as they had been down the road before. Good Luck! Sean |
RE: Change in idle today..
My money on a fuel pump getting ready to go away.................been there done that 3 times...................
John |
RE: Change in idle today..
John, it could be the stabilization parameter that sets the PID to idle amongst a dozen other things including the pump. If it's running on the highside, I think the newer ECU's have a requirement to run to full throttle for a minute and then back to idle over a minute then sit at idle, etc. I think this is discussed somewhere like the manual or in the turbine clinic, or call Eric.
Still wouldn't stop me from flying, but I'm a bit carefree! :D Light them suckers with a bic lighter and let's go fly! |
RE: Change in idle today..
Pete
Hi I have a Wren MW54 that did the same thing. The ECU is a Fadec the idle was set to 45,000 RPm. What happened to me was it would come down to about 50,000 to 52,000 and stay there. I found out from Wren USA that the Deceleration delay needed to be increased to let it come down to the 45,000 RPM setting. This was actually happening to me in flight and making it harder to land the plane with the residuale thrust. I also found out that snapping the throttle from full to idle quickly would cause this same thing to happen. After increasing the the deceleration delay the issue went away. I was also told that on some of the earlyer FADEC ECU's that this condition is an actuall program in the ECU to allow the idle to reset at a higher setting to prevent an engine shutdown from quickly pulling the throttle from full power to idel. Don't know if this helps but good luck. Joe |
RE: Change in idle today..
ORIGINAL: Pete737 Maybe Im going nuts, But I don't think so. I noticed that while taxiing and doing brake tests today, At about 1/4 fuel left the idle increased slightly. Barely noticable but the plane would not stop without the brakes. Only thing different about todays run was the turbine oil percentage. I used 2.5% instead of 4-5% like the last batch, Something tells me that's not the cause. Any suspects come to ind? Anything I should check on the data terminal? Thanks! Pete 1 . Change in fuel system? filters replaced? new UAT? the FADED runs auto calibration , if the pump runs "lighter"after a filter change or Tubing replacement the ecu needs time again to adjust. this seesm to be your case start the engine let it run in idle . go slowly from idle to full throttle leave it at full for 10 seconds , come down again to idle. problem should go away. |
RE: Change in idle today..
ORIGINAL: cactusflyer My money on a fuel pump getting ready to go away.................been there done that 3 times................... John Ditto, same thing happened with my sim jet 3000... higher idle, and sometimes it would surge +/- a few thousand rpms's at idle... any smoke coming from your fuel pump on start up? |
RE: Change in idle today..
Thanks guys! No smoke coming from the pump. The pump and engine altogether has less than 2 hours on it, Id be disapointed if it was going. only new thing today was the fuel (less oil). I do sometimes bring the throttle down quickly from full power.
Today Ill run it again and excercise the throttle slowly like you said and see what happens. Seanreit, yes I have some guys to meet up with the day of the maiden. Thanks! Pete |
RE: Change in idle today..
Hello Pete
The idle speed for the falcon is 36k regards Juan |
RE: Change in idle today..
Pete, i agree with Sean......get some hands on help with your questions, it will save you the confusion later when you go to advance the throttle. Nick
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RE: Change in idle today..
ORIGINAL: monjet Hello Pete The idle speed for the falcon is 36k regards Juan Pete |
RE: Change in idle today..
ORIGINAL: seanreit Pete, I have noticed your increased posting here and your questions are very good ones so please don't take this the wrong way. Are there any regular turbine guys in your area? There are a lot of real experts here on RCU, and really two of the more trusted in my opinion have even posted in this thread. But I fear as your big day approaches you might be saturated from differing opinions here. I would sincerly suggest if there are local turbine guys to you that you have them go through your airplane and give you a hand on your big day. OK, off my soapbox. I have had a couple of falcons and they can from time to time make a revving sound. Because I've heard about 10,000 turbine runs, I'm usually looking to hear something more sinister than idle changes before I'm giving up on some flying action. There are some here that might remind me of my first big day "Is that Normal" [sm=bananahead.gif] ???? You're in good company, but again, nothing was more helpful to me than digesting what those in my local area were helping me accomplish as they had been down the road before. Good Luck! Sean How much can you prepare?:) |
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