M20J: What speed do you flight plan?

[bnicolette]

Quote: Bnicolette

I generally plan on 160 kts between 6 - 8 thousand feet.  I find that I am generally 158 - 164 kts on the airspeed indicator in smooth air.  ROP

[Cruiser]

Brett, according to my POH 24.9x2600 is almost exactly 75% power at 12.3 gph.

Why is the JPI showing only 69%?

[John Pleisse]

I like the indicated on your left pic.

I guess you've heard it living in Houston, but my first night ever spent in Orlando...2am....BAM....BAM (sonic boom)!!! The bedroom door shook. I walkied into the living room to turn on the TV and the shuttle was already flaring over the runway at Cape C. What's that, a 15 second walk from the bedroom? 50 miles ORL- to Cape C?

 

Re: M20J: What speed do you flight plan?
Posted May 3, 2012 7:43 PM

Mach .88 works pretty well, unless I am flying the space shuttle simulator, then its M 25.0 !

makes a Mooney feel awful slow.

« Last edit: May 3, 2012 7:43 PM by jetdriven»

Byron
1977 M20J
KLVJ Houston, TX

Attached Images

[bnicolette]

Quote: Cruiser

Brett, according to my POH 24.9x2600 is almost exactly 75% power at 12.3 gph.

Why is the JPI showing only 69%?

[bnicolette]

Quote: Bnicolette

Cruiser, I'm not really sure.  I haven't paid that much attentionut to that number before.  Is it possible to make that number more accurate?  Anybody?

[Jeff_S]

I flight plan for 150KTAS and can usually get that in cruise with WOT and LOP, generally burning something around 9.5gph or less at higher altitudes.  I've tried the ROP route to pick up a few knots, but in my plane the best I would usually see is 155-157KTAS at 12.5gph.  Do the math...4% more speed for 30% more fuel. To me it's a no brainer.

[Cruiser]

Quote: Jeff_S

I flight plan for 150KTAS and can usually get that in cruise with WOT and LOP, generally burning something around 9.5gph or less at higher altitudes.  I've tried the ROP route to pick up a few knots, but in my plane the best I would usually see is 155-157KTAS at 12.5gph.  Do the math...4% more speed for 30% more fuel. To me it's a no brainer.

[jetdriven]

Its more like

155 KTAS 12.5 GPH ROP =  12.4 NMPG

150 KTAS @ 9.2 GPH = 16.3 NMPG

Which is a 30% improvement in the biggest line cost item.  Actually fuel makes up over 3/4 of your marginal hourly cost.  Now a 300 NM trip is a little short for a Mooney, buy you eventually must return.  So call it 600 NM. So, correcting for that,

(no wind, 3 GAL extra added for climb to 7K and taxi, per leg)

ROP  3:52 hours, 54.4 gallons

LOP 4 hours, 42.8 gallons.

You fly an extra 8 minutes and save yourself 11.6 gallons.  63$ in 8 hours.  Fly this way all the time, 150 hours a year thats 1200$ a year.   Free insurance, fly LOP.  OR, free engine, fly LOP. 

Extend that flight out past 650 NM per leg, and you have to make a fuel stop ROP, the LOP has another 150 miles of range.  That right there saves you another 40$.

 

 

 

[bnicolette]

I guess I'm really gonna have to give this LOP a solid try.  I have played with it before and know my plane will run there with no issues, but never paid much attention to the speed loss.  Mike says he loses 10 kts and Byron, you say 5 kts..  Which one is typical and what should I expect?  Thanks all.

[John Pleisse]

Check these turkeys out..... they love to fly 135kts. Check their Flightaware....... Just say'in......

 

 

[Bennett]

My last flight to Scottsdale, AZ (KSDL) from San Carlos, CA (KSQL) was at 9,500 with a True Airspeed of a bit over 160 Kts. I was running at 2520 RPM, 10.4 Gal/Hr, MP (with ram air open) above 22" (I don't recall the exact number), and oil temp was under 190 degrees, all CHTs under 360 degrees, cowl flaps closed, and I landed with 26 plus gallons of reserve fuel (took off with 64 gallons)  The route was KSQL, OSI (Woodside VOR), SNS (Salinas VOR), PMD (Palmdale VOR), Soggi intersection, User Waypoint halfway to PSP (Palm Springs VOR), BLH (Blythe VOR), BXK (Buckeye VOR), KSDL. Mooney efficiency demonstrated. The trip took about 3hrs and 20 minutes, even with all the jilling around to avoid Phoenix Class B airspace.  I wanted to enjoy a simple VFR flight in great weather. Flew back at 8500' with about the same numbers except it took about a half hour longer due to some headwinds in California. Gotta love the M20J

[Jeff_S]

Quote: N4352H

Check these turkeys out..... they love to fly 135kts. Check their Flightaware....... Just say'in......

 

 

[jetdriven]

Too many steps.  And he is going to slow down some with that 21" of MP.  So he could add 2" of MP to recover the power loss, or simoly leave the throttle WOT, and lean to 7.1 GPH. Done.   Its that easy at 1,500'.   That would be about 55% power. 

[Bolter]

Quote: Bnicolette

I guess I'm really gonna have to give this LOP a solid try.  I have played with it before and know my plane will run there with no issues, but never paid much attention to the speed loss.  Mike says he loses 10 kts and Byron, you say 5 kts..  Which one is typical and what should I expect?  Thanks all.

[scottfromiowa]

Quote: M016576

That is a beautiful airplane!

[scottfromiowa]

Quote: jetdriven

Its more like

155 KTAS 12.5 GPH ROP =  12.4 NMPG

150 KTAS @ 9.2 GPH = 16.3 NMPG

Which is a 30% improvement in the biggest line cost item.  Actually fuel makes up over 3/4 of your marginal hourly cost.  Now a 300 NM trip is a little short for a Mooney, buy you eventually must return.  So call it 600 NM. So, correcting for that,

(no wind, 3 GAL extra added for climb to 7K and taxi, per leg)

ROP  3:52 hours, 54.4 gallons

LOP 4 hours, 42.8 gallons.

You fly an extra 8 minutes and save yourself 11.6 gallons.  63$ in 8 hours.  Fly this way all the time, 150 hours a year thats 1200$ a year.   Free insurance, fly LOP.  OR, free engine, fly LOP. 

Extend that flight out past 650 NM per leg, and you have to make a fuel stop ROP, the LOP has another 150 miles of range.  That right there saves you another 40$.

 

 

 

[scottfromiowa]

Quote: Cruiser

166 KTAS @ 12.5 gph = 13.28 mpg

150 KTAS @ 9.2 gph = 16.3 mpg

about 3 mpg difference. On a 300 nm trip that 4.2 gallons of fuel .... about $25 for 11.5 minutes longer flight time.

[scottfromiowa]

Quote: N4352H

I like the indicated on your left pic.

I guess you've heard it living in Houston, but my first night ever spent in Orlando...2am....BAM....BAM (sonic boom)!!! The bedroom door shook. I walkied into the living room to turn on the TV and the shuttle was already flaring over the runway at Cape C. What's that, a 15 second walk from the bedroom? 50 miles ORL- to Cape C?

 

Re: M20J: What speed do you flight plan?

Posted May 3, 2012 7:43 PM

Mach .88 works pretty well, unless I am flying the space shuttle simulator, then its M 25.0 !

makes a Mooney feel awful slow.

« Last edit: May 3, 2012 7:43 PM by jetdriven»

Byron

1977 M20J

KLVJ Houston, TX

Attached Images

[scottfromiowa]

Quote: Bnicolette

Followinng is a video that I made this morning on the way to work.  It's only a :20 flight so even going up to 5000' is a waste but that is generally where PIT APCH will send me:  Also attached is the nav page from fltplan.com for this mornings flight.

5000', temp was +19c, 2600RPM, WOT, ROP = 166KTAS (Indicated).

G/S was showing 145kts and fltplan was showing approx 19kts headwind.

[201er]

Quote: Bnicolette

I guess I'm really gonna have to give this LOP a solid try.  I have played with it before and know my plane will run there with no issues, but never paid much attention to the speed loss.  Mike says he loses 10 kts and Byron, you say 5 kts..  Which one is typical and what should I expect?  Thanks all.

[jetdriven]

Ours doesnt peak at that high of a FF.  Just a week ago I did a flight, and logged the results.  At 5500', 55dF OAT, 29.99 the density altitude was 6,500'. 

Full throttle 24.5" MP, 2400 RPM, IAS 137 KT, TAS 150 KT. 

At 10 LOP, the FF was 8.9.   Thats 67% power.

 

 

[scottfromiowa]

Quote: jetdriven

Ours doesnt peak at that high of a FF.  Just a week ago I did a flight, and logged the results.  At 5500', 55dF OAT, 29.99 the density altitude was 6,500'. 

Full throttle 24.5" MP, 2400 RPM, IAS 137 KT, TAS 150 KT. 

At 10 LOP, the FF was 8.9.   Thats 67% power.

 

 

[jetdriven]

Quote: scottfromiowa

And it's FREE speed.  N.I.C.E!  Nothing like going downhill.

[xftrplt]

Deleted. 

[xftrplt]

Sorry for double deletions; (I give up trying to post pics.)