joegoersch Posted June 17, 2014 Report Posted June 17, 2014 I was just wondering what other people see in terms of fuel flow at takeoff in a M20J (sea level, wide-open throttle, full rich). Is 18.5-19 gph too rich ? Is it reasonable to lean before 3000 feet if CHTs are low ? say leaning to 15-16 gph... joegoersh Quote
Marauder Posted June 17, 2014 Report Posted June 17, 2014 I have the same question for an F model with an IO-360 A1A. Just changed out my fuel flow transducer and I am seeing 16 GPH with the same conditions (sea level, WOT, full rich). My cylinder temps never get above 380. Am I running too lean? I am in the process of looking at my old flight data to see what it was on the old transducer but I think it was still below 17. Sent from my iPad using Tapatalk Quote
1964-M20E Posted June 17, 2014 Report Posted June 17, 2014 As best I can recall I'm about 16 to 17GPH +/- during takeoff and climb out and I'm at sea-level. CHT looks good through 3000 feet. I'll start backing off on FF as I'm approaching 3000' watching CHT and EGT target temp leaning ops as discussed in other threads. I do not want to get into a discussion on LOP vs. ROP. About the only other thing I’ll do is back off on RPM to just under 2600 during climb out. Quote
PTK Posted June 17, 2014 Report Posted June 17, 2014 I was just wondering what other people see in terms of fuel flow at takeoff in a M20J (sea level, wide-open throttle, full rich). Is 18.5-19 gph too rich ? Is it reasonable to lean before 3000 feet if CHTs are low ? say leaning to 15-16 gph... joegoersh I'm seeing 20 +/- some change gph on t.o. from ~55 ft msl. At 1000 agl 2450 and start leaning via target EGT all the way up to cruising alt. WOT from t.o. to maneuvering for approach and landing. I climb at Vy+10 or 15 or so, shoot for ~115 KIAS. Hottest CHT 380 or so. I'm convinced that the best blend for efficiency, speed and engine longevity in my J is 60-65% power LOP. Quote
wishboneash Posted June 17, 2014 Report Posted June 17, 2014 I use the target EGT method which is about 1380 deg in my J. That results in about 16-17 gph near sea level. Quote
Bob_Belville Posted June 17, 2014 Report Posted June 17, 2014 IO360A1A Pressure alt 240'(Greenville MS) Take off roll: 29.0/2690 (95% indicated) = 18.1 max flow. earlier that day, from Kerrville alt ~1600' 27.8/2690 (94% indicated) = 18.5 max flow Quote
N201MKTurbo Posted June 17, 2014 Report Posted June 17, 2014 I usually see about 16.5. I burned up my turbo once leaning in the climb, so I don't do it any more. Cost $2200.00 Quote
KSMooniac Posted June 17, 2014 Report Posted June 17, 2014 Our 200 HP Lycomings should be in the 18-18.5 range for full power, full rich takeoff near sea level. Jim's explanation of the Target EGT method for leaning is best practice too, but not for Turbo engines which should stay full rich until the cruise power reduction. Generally speaking, fuel flow in GPH should be in the ballpark of 9% of the rated power at takeoff. (I think I got that figure from APS long ago) 2 Quote
larryb Posted June 17, 2014 Report Posted June 17, 2014 I see 18.5 GPH at sea level. I use Target EGT method in the climb. 1 Quote
aaronk25 Posted June 17, 2014 Report Posted June 17, 2014 17.5gph but I pull it back to 16gph at 1000agl which is about 80 egt hotter than the full rich roll at 1,300 msl. As long as your at least 125-150rop and you don't bust the 380cht, my advice would be to lean. Id rather use more cowl flap and lean more to keep CHTs in line. Cleaner and less fuel and slightly more power. Full cowl flaps are a bit draggy but I'll set mix as lean as possible during climb as long as I don't bust the CHT limit of 380. Obviously I don't go any leaner than 100rop, because it will bust temp limits quick and after 80rop power drops off. I got about 1700 hours on the cylinders too. Quote
Alan Fox Posted June 17, 2014 Report Posted June 17, 2014 I burn 18 plus on initial climb out , at 1000 feet I will pull back to 2500 24 inches , I don't pull back on the mixture until I level off...... Quote
KSMooniac Posted June 18, 2014 Report Posted June 18, 2014 I burn 18 plus on initial climb out , at 1000 feet I will pull back to 2500 24 inches , I don't pull back on the mixture until I level off...... Why do you pull back the power? It is now widely considered to be the wrong action to take... Quote
bnicolette Posted June 18, 2014 Report Posted June 18, 2014 I used to see 18.3 all the time during the takeoff roll. I would lean to target egt which was about 1250 Quote
aaronk25 Posted June 18, 2014 Report Posted June 18, 2014 I burn 18 plus on initial climb out , at 1000 feet I will pull back to 2500 24 inches , I don't pull back on the mixture until I level off...... I'm curious to to here why?, if you care to share..... Are you operating a turbo? I'm guessing you are or I'd like to follow behind with a bucket and catch the extra fuel your blowing out..... Quote
Bob - S50 Posted June 18, 2014 Report Posted June 18, 2014 We see about 18 GPH at takeoff. As for reducing RPM after takeoff, that will increase peak pressure and stress on the engine and works against the reason we run so rich for takeoff in the first place. I too pick an EGT (usually #4) and lean in the climb to keep it about the same all the way to level off. For me, that's usually in the 1250 to 1300 range. Bob Quote
marks Posted June 18, 2014 Report Posted June 18, 2014 I see 18.5 on my J every time. When I had my Sierra with virtually the same engine I also saw 18.5. My field is just about at sea level. After 1,000 ft I climb at 110 kts and lean to 16. Temps always seem cooler than in cruise. Quote
joegoersch Posted June 18, 2014 Author Report Posted June 18, 2014 O.k. so a lot of side discussions. But it seems like 18.5 is fine and doesn't need to be looked into at next annual... thanks. Quote
carusoam Posted June 18, 2014 Report Posted June 18, 2014 Joe, Are you familiar with the official document for your engine and plane that defines the FF during T/O? It's good to get pilot's opinions to back up the "required" settings. I believe the document may be the TCDS? http://www2.anac.gov.br/certificacao/produtos/Espec/EA-8701-02i.pdf I'm only a PP, not a mechanic and my memory is incredibly aged..... Can anyone verify the document name? Best regards, -a- Note: I was unable to find FF data in the document. It must be somewhere else....! The TCDS is a good read.... 1 Quote
Guest Posted June 19, 2014 Report Posted June 19, 2014 A good general run of thumb is just less than 10 %of rated horse power, so just under 20 GPH for a 200 HP Mooney. Usually 10% or more for a turbo charged engine. If in doubt the engine PoH will have the correct values. Clarence Quote
Hank Posted June 19, 2014 Report Posted June 19, 2014 I would suggest checking the Performance Tables in the POH. YOUR j should be recent enough to have one of these; even those tables in my Owners Manual give fuel glow, but our engines are very different so my numbers don't matter. Quote
Alan Fox Posted June 19, 2014 Report Posted June 19, 2014 As for why I don't pull the mixture back until I level off , there are two ways to keep an engine cool , Air over the cylinders , and rich fuel mixture..... 1 Quote
PTK Posted June 19, 2014 Report Posted June 19, 2014 As for why I don't pull the mixture back until I level off , there are two ways to keep an engine cool , Air over the cylinders , and rich fuel mixture..... I burn 18 plus on initial climb out , at 1000 feet I will pull back to 2500 24 inches , I don't pull back on the mixture until I level off...... Why pull back power in climb Alan? Quote
Alan Fox Posted June 19, 2014 Report Posted June 19, 2014 I cruise climb at 75% , 300 FPM , just what I do , not telling anyone else to do the same..... Quote
OR75 Posted June 23, 2014 Report Posted June 23, 2014 If you needed another data point ... 18.2 gph on takeoff for me this afternoon Quote
jetdriven Posted June 23, 2014 Report Posted June 23, 2014 As for why I don't pull the mixture back until I level off , there are two ways to keep an engine cool , Air over the cylinders , and rich fuel mixture..... but the mixture gets richer with altitude, hence the target EGT method. horsepower goes down with altitude also, which is why the target EGT actually is still a bit rich at higher altitudes 3 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.