slowflyin Posted January 29, 2015 Report Posted January 29, 2015 I've been trying to refine my "flying by the numbers" and have found this forum and the MAP manual invaluable. However, I'm having trouble implementing all the great info regarding IFR approach settings while respecting my 2000-2350 rpm restriction. It seems anything below 14.5-14.75" of MP puts me in the red. Any advice? Thanks in advance. PS-M20F Quote
MooneyBob Posted January 29, 2015 Report Posted January 29, 2015 What phase of the flight / approach you are under 15" of MP? For how long? What is the speed? Quote
slowflyin Posted January 29, 2015 Author Report Posted January 29, 2015 During an IFR approach while running down hill on the GS. 15 yields around 95-100 kts with flaps at approach. The MAPA manual and others have suggested 13 inches while on the glide slope. Quote
MooneyBob Posted January 29, 2015 Report Posted January 29, 2015 I don't remember exactly what my place card says but I think the RPM restriction applies over 80 knots and for longer period of time. I might be wrong. Quote
N201MKTurbo Posted January 30, 2015 Report Posted January 30, 2015 Do you have the wheels down? 2 Quote
HRM Posted January 30, 2015 Report Posted January 30, 2015 I've been trying to refine my "flying by the numbers" and have found this forum and the MAP manual invaluable. However, I'm having trouble implementing all the great info regarding IFR approach settings while respecting my 2000-2350 rpm restriction. It seems anything below 14.5-14.75" of MP puts me in the red. Any advice? Thanks in advance. PS-M20F I believe the wording is avoid continuous operation. That means, stay out of there during cruise. Landing, which other than taxi puts the least strain on the aircraft, is not a place to worry about being in the red. Quote
N201MKTurbo Posted January 30, 2015 Report Posted January 30, 2015 I personally think that case cracks are caused by operating in the red zone. I would avoid it. Torsional vibration is insidious it can't always be felt but puts tremendous stress on the crank and case. Quote
carusoam Posted January 30, 2015 Report Posted January 30, 2015 90% of power input comes from MP the other 10% comes from RPM... While trying to select speeds and settings that work for the situation... Consider using an rpm that is outside the limitation, then adjust the MP to get the performance you are looking for. With the O1... 2500RPM is the key setting. Adjust MP to get the speed you are looking for... Does that cover what you are asking about? Best regards, -a- Quote
Bob_Belville Posted January 30, 2015 Report Posted January 30, 2015 @ 15" I assume the gear is down otherwise the gear alert should be blaring. And with the gear down I would be very surprised that the prop is in the restricted zone unless you're practicing approaches with a big tailwind. Quote
Marauder Posted January 30, 2015 Report Posted January 30, 2015 I fly approaches in my F at 100 KIAS, flaps at 15 degrees. Try 16" 2400 RPM leading up to the FAF. This will keep under the 104 VLo. At FAF, gear down. This should keep you stabilized at 100 with around 450 FPM decent. At the DA with field sighted, I drop in 33 degrees of flaps and reduce MP to 12". Did you make out a power setting chart? If so, post it please. Some of the mods on an F will change these numbers. Be curious to see how mine compare. Based on what you spot above, I'm wondering if your flaps are out. If they are not, good luck getting the numbers too work. You would need to drop the MP to keep the speed under control. Quote
Ratherbflying Posted January 30, 2015 Report Posted January 30, 2015 I believe the wording is avoid continuous operation. That means, stay out of there during cruise. Landing, which other than taxi puts the least strain on the aircraft, is not a place to worry about being in the red. I was talking to a Hartzell technician about this just the other day. "Avoid Continuous Operation" means you can traverse the red zone but don't let the needle stop. Cruise, landing, whatever. Keep the needle moving until you get out. 3 Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 Do you have the wheels down? Yes Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 @ 15" I assume the gear is down otherwise the gear alert should be blaring. And with the gear down I would be very surprised that the prop is in the restricted zone unless you're practicing approaches with a big tailwind. Yes, gear down, red zone below 14.5. I'm fine at 15" but I'd like a slower approach for some fields. Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 90% of power input comes from MP the other 10% comes from RPM... While trying to select speeds and settings that work for the situation... Consider using an rpm that is outside the limitation, then adjust the MP to get the performance you are looking for. With the O1... 2500RPM is the key setting. Adjust MP to get the speed you are looking for... Does that cover what you are asking about? Best regards, -a- With the prop full forward RPM drops with MP when you get in the lower MP ranges. For my bird anything below approximately 14.5-15" MP and the RPM drops below 2350 into the red zone even with the prop full forward. Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 I fly approaches in my F at 100 KIAS, flaps at 15 degrees. Try 16" 2400 RPM leading up to the FAF. This will keep under the 104 VLo. At FAF, gear down. This should keep you stabilized at 100 with around 450 FPM decent. At the DA with field sighted, I drop in 33 degrees of flaps and reduce MP to 12". Did you make out a power setting chart? If so, post it please. Some of the mods on an F will change these numbers. Be curious to see how mine compare. Based on what you spot above, I'm wondering if your flaps are out. If they are not, good luck getting the numbers too work. You would need to drop the MP to keep the speed under control. No chart yet, that's what I'm working on. I'll try the 12" and see if it gets my RPM out of the red on the other end. Thanks Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 No chart yet, that's what I'm working on. I'll try the 12" and see if it gets my RPM out of the red on the other end. Thanks I meant to say, 12" on the end of the approach. I'll post the numbers as I get them worked out. My F does have the 201 front end and most of the 201 mods. Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 Thanks for all the input gents. As always, lots of knowlege. Quote
Marauder Posted January 30, 2015 Report Posted January 30, 2015 No chart yet, that's what I'm working on. I'll try the 12" and see if it gets my RPM out of the red on the other end. Thanks If I get some energy today, I will run over to the airport and pull the card I made 20+ years ago and the one I hang in front of the co-pilot's seat when I do IPCs with a non Mooney proficient instructor. It might get you some starting points. I hit the red range but not on an approach, it usually a pass through as I am slowing to final landing speed. 1 Quote
carusoam Posted January 30, 2015 Report Posted January 30, 2015 Questions that come to mind... If the MAPA book suggest one thing... And an individual plane wants to do something else... It may help to review what the governor limitations are... What governor do you have? When was it OH'd last? There may be newer designs that could help with your situation? I remember doing an OH on my O360’s governor, but none of the details that went with it... 1-2 amu (hardware cost) for a new one? Or maybe this...? http://mooneyspace.com/topic/14066-fs-pcu5000-ath-1/?hl=governor Best regards, -a- Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 Questions that come to mind... If the MAPA book suggest one thing... And an individual plane wants to do something else... It may help to review what the governor limitations are... What governor do you have? When was it OH'd last? There may be newer designs that could help with your situation? I remember doing an OH on my O360’s governor, but none of the details that went with it... 1-2 amu (hardware cost) for a new one? Or maybe this...? http://mooneyspace.com/topic/14066-fs-pcu5000-ath-1/?hl=governor Best regards, -a- Thanks for the input, I'll track it down in the logs. I know the prop is around 400 hours since new but don't recall the gov. Quote
RobertGary1 Posted January 30, 2015 Report Posted January 30, 2015 Or just get the A3B6 engine. I have no limitations other than the 2700 RPM red line. -Robert Quote
Hank Posted January 30, 2015 Report Posted January 30, 2015 I generally have to add about 3" MP when I drop Takeoff flaps to hold altitude. The gear goes down 1-1/2 dots above glideslope and I come right down all centered unless I screw up. Quote
Bob_Belville Posted January 30, 2015 Report Posted January 30, 2015 I did not even sleep at a Holiday Inn Express last night but I would bet that the rpm restriction is not applicable when the rpm is being controlled by the throttle as contrasted with the prop governor. IOW, 25" and 1900 RPM is surely stressing the drive train where 15" & 1900 rpm is not. Quote
Ratherbflying Posted January 30, 2015 Report Posted January 30, 2015 I did not even sleep at a Holiday Inn Express last night but I would bet that the rpm restriction is not applicable when the rpm is being controlled by the throttle as contrasted with the prop governor. IOW, 25" and 1900 RPM is surely stressing the drive train where 15" & 1900 rpm is not. Bob, it's not about engine power, it is about harmonics. You can read about it at: https://answers.yahoo.com/question/index?qid=20070619132438AAJJFTG The actual restriction is contained in the Propeller Type Certificate. You need your Hub model (e.g. C2YR-....) , blade model (e.g. F7666), and engine (e.g. O-360-A1D). For Hartzell, go to http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/802f367a21c7e7fc86257d00004d5d82/$FILE/P-920_Rev_34.pdf and look up your information in the table. Bob, there are some combinations that take MP in to consideration, but on my C the restriction is RPM range based. Period. 1 Quote
slowflyin Posted January 30, 2015 Author Report Posted January 30, 2015 I generally have to add about 3" MP when I drop Takeoff flaps to hold altitude. The gear goes down 1-1/2 dots above glideslope and I come right down all centered unless I screw up. That's how I've been managing the approach. Many advised no flaps but the only way I can keep the speed down with 14.5" MP is flaps to approach. Quote
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