Typical M20C speeds (TAS)

[kevmor]

I did a lot of searching but wasn't able to find it for C models. What are you guys seeing for an early M20C model ('64-66) for TAS and fuel burn? On purchasing a used one, do you think I could expect at least 140 kts on 10gph?  This would be stock, no speed mods. I think this is what the POH says, but I thought it was on the high side.

[Z W]

140-145 KTAS with all the speed mods @ 10 GPH. I plan 140.  YMMV.

 

If you're shopping, lots of good examples on the market with speed mods.  I'd put them high on the priority list, in particular the 1-piece windshield and front cowl closure which also helps cooling.

[TTaylor]

Stock 63 I used to plan for 135 KTAS and 9.5 GPH.  That was always 2500 rpm, full throttle and leaned as far as I could.  That was for 8,500 to 11,500 feet.  You might go faster lower with higher fuel burn. 

[Oscar Avalle]

140-145 KTAS with all the speed mods @ 10 GPH. I plan 140.  YMMV.

 

If you're shopping, lots of good examples on the market with speed mods.  I'd put them high on the priority list, in particular the 1-piece windshield and front cowl closure which also helps cooling.

My M20C is a 70 model, it has many speed mods, including the 1 piece windshield and the cowl closure and I also see 135-140 kts @9.0 gph at 11000 and 12000 feet.

[BigTex]

I flight plan for 144 knots @ 10gph.

[kevmor]

I flight plan for 144 knots @ 10gph.

 

Is that with any speed mods? What altitude and MP/RPM? Thanks

[lahso]

1966 C, with speed mods. 148KTAS with 10 GPH. Generally fly between 6-8,000 ft.

[Openwheeler3]

I see 142-144 KTAS at approx 9 GPH between 8,500 and 11,500 in a '65 C with no speed mods. 20 in MP or full throttle, whichever is less, and leaned until just prior to engine roughness.

[gregwatts]

I think some of you guys are stretching it a bit......my first Mooney was a 68 C model with several mods.......140kts was best I ever saw!

[Sabremech]

I flight plan 148 TAS and my numbers are spot on for my 1966 M20C. Every speed mod except for flap fairings installed. Full throttle at 2500 rpm up to 9500 at most and a little over 10 gph.

[N33GG]

68C all stock except prop which is 2 blade Scimitar. I fly 6-8kft 143-145 kts TAS with WOT 2400 rpm and close to 11 gph. One of my cylinders peaks and goes lean well before the other 3. Otherwise, I could be closer to 10 gph, but that's just the way it is with my engine. The prop helped my TAS significantly. Before the Scimitar, I was in the 135-137 range with a 3 blade, and never saw 140 TAS. FWIW and YMMV, as always.

[jrwilson]

63C, 3 blade prop, cowl enclosure, aileron gap seals, brake rotation.  144 KTAS mid to high weights at around 8,000'.  10GPH.

[Hector]

67C with most of the speed mods. I see 142 Kts between 7-9k, WOT, 2400 RPM, around 10 GPH

[rob]

148kts at 7-9000 with about 650lbs onboard. Brake reversal and cowl closure only speed mods. 2500 and WOT. Leaned aggressively gets me down to 9 gph or so.

Not overestimating at all, been checked six ways from Sunday and countless flights on flightaware confirm.

[jetdriven]

The only way to actually verify TAS is a 3-track GPS verified groundspeed put into an NTPS excel formula.  Further, in the M20J, the CAS is 2 knots less than IAS, before corrections for density altitude.  PM me for the excel spreadsheet.

[stevesm20b]

I have a "B" model with all the speed mods except one piece belly. I have 3 blade prop and I do 150+kts at 6000 to 8000. I average 10gph for the entire flight including startup, taxie, runup and flight. Most of the time I run FT and 2400 to 2500 leaned till rough then rich till it smooths out. Check flight aware for my speed and alt. 

[Lood]

Mmmm, it seems that I should've bought a C instead. I haven't done a speed test with my new engine, but just about all the above mentioned C models are faster than my F. Some are WAY faster...

[Hank]

My M20C is a 70 model, it has many speed mods, including the 1 piece windshield and the cowl closure and I also see 135-140 kts @9.0 gph at 11000 and 12000 feet.

 

I also have a 1970 with 201-windshield and wingtips, the cowl closure and a 3-blade. I typically see book speed [160-165 MPH] at 9.0-9.2 gph block fuel burn, cruising 8-10K. Short food runs at 3000 msl, 23"/2300 are typically slower [135-140 indicated + 6% = 143-148 mph]. I have a single-point EGT, no fuel flow, fly ROP, and when high run closer to peak and generally 2500. At 10,000 msl, I often indicate around 135 mph [+20% = 162 mph]; here's a picture of that. Ground speed, of course, varies significantly--my sustained level-flight ground speed envelope is currently 68 knots to 183 knots, in the 6000-10,000 msl range.

[Hank]

Mmmm, it seems that I should've bought a C instead. I haven't done a speed test with my new engine, but just about all the above mentioned C models are faster than my F. Some are WAY faster...

 

They don't say that C-models are "the best bang for the buck" for no reason! 

[carusoam]

Byron, PM coming your way... -a-

[Marauder]

That does it, I'm selling my F!! Sent from my Nexus 7 using Tapatalk HD

[rob]

The truth (4-way gps run) will set you free

 

Simply flying the cardinal directions and then averaging the speeds on the GPS is only accurate in a zero wind situation. A three way GPS run with some trig will give a more accurate number. Of course, if you add a fourth leg in there, the accuracy will improve, but either way, there is some trigonometry required to get accurate results. This is covered many times over on aviation forums across the Internet.

[triple8s]

147kts @ 8000 - 10000 wot and 2500

[Lood]

There aren't many Mooney's in South Africa and even less participate in our annual Presidents Trophy Air Race, which is a handicapped race held over two days and about 600nm. Every year, there's a lot of debate with regards to the handicap system and many pilots are rather unhappy with the handicap speeds given to their specific airplane.

Anyhow, in this race, everybody fly balls to the walls, low level and they try to get every last bit of speed out of their airplanes. Depending on the accuracy of their navigation, of course, the speed of the front pack over the two are pretty much representative, in my opinion, of what a specific airplane is capable of. All airplanes carry loggers to capture the relevant speed, altitude and track data. In a non-navigation and along a straight line situation, the top speeds will thus be higher than in this race.

Just for interest sake, I worked out an average speed for the few Mooney's that have participated over the last 15 races or so and here are the results:

 

M20J - 159 kt (average of 10 results)

M20F - 148 kt (average of 6 results)

M20E - 148 kt (average of 5 results - not representative in my opinion)

M20C - 143 kt (average of 11 results)

 

I must add that very, very few Mooney's here have any mods and apart from avionics and instruments, most are stock standard. It also seems that our E models lack something serious as they are normally on par with the J's in terms of speed.

Please, note that I'm not insinuating anything about anybody's claimed speed, I just did this exercise for fun and to compare the local Mooney's to those in the US.

The conclusion that I tend to come to is that speed mods are most certainly worth it.

[TTaylor]

There aren't many Mooney's in South Africa and even less participate in our annual Presidents Trophy Air Race, which is a handicapped race held over two days and about 600nm. Every year, there's a lot of debate with regards to the handicap system and many pilots are rather unhappy with the handicap speeds given to their specific airplane.

Anyhow, in this race, everybody fly balls to the walls, low level and they try to get every last bit of speed out of their airplanes. Depending on the accuracy of their navigation, of course, the speed of the front pack over the two are pretty much representative, in my opinion, of what a specific airplane is capable of. All airplanes carry loggers to capture the relevant speed, altitude and track data. In a non-navigation and along a straight line situation, the top speeds will thus be higher than in this race.

Just for interest sake, I worked out an average speed for the few Mooney's that have participated over the last 15 races or so and here are the results:

 

M20J - 159 kt (average of 10 results)

M20F - 148 kt (average of 6 results)

M20E - 148 kt (average of 5 results - not representative in my opinion)

M20C - 143 kt (average of 11 results)

 

I must add that very, very few Mooney's here have any mods and apart from avionics and instruments, most are stock standard. It also seems that our E models lack something serious as they are normally on par with the J's in terms of speed.

Please, note that I'm not insinuating anything about anybody's claimed speed, I just did this exercise for fun and to compare the local Mooney's to those in the US.

The conclusion that I tend to come to is that speed mods are most certainly worth it.

 

 

This matches the data in the Mooney Pilot's review:

 

http://www.mooneypilots.com/mapalog/M20J%20Evaluation/M20J_evaluation_report.html

 

Altitude Ram Air GPS Derived Cruise Speed (KTS)     M20J M20E M20F M20C 10000 on --- --- 145.25 --- 10000 off 158 145.5 144 139 7000 on --- 153.75 150.5 --- 7000 off 162 149.5 147 143.5 4500 on --- 151.5 151.25 --- 4500 off

160.75

149.25 148 146.75

 

 

Depending on altitude the 20J is about 10 knots faster, the E and F are within one knot and the C falls off a little more as altitude goes up.  Also depends on how rich you want to run and fuel flow.  I tend to fly LOP so lose a little speed for the better economy.