Improved speed documented

[ArtVandelay]

FWIW, an IFD540 and a G5 will do this nicely, too.   I hope folks can zoom on this pic sufficiently to see, but it is computing TAS as well as the current wind aloft and headwind/tailwind component.   It's pretty cool.

You can remove the taped on screen protector on the JPI, it’s not like the labels on pillows.

[Marauder]

semi related question: does the Lasar cowl closure require repositioning the oil cooler?

Nope.




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[mike_elliott]

3 hours ago, aviatoreb said:

I have timed climbs to 17 in under 13 minutes.

.and thats impressive!

[aviatoreb]

23 minutes ago, mike_elliott said:

.and thats impressive!

..winter - and we get chilly winters - and solo - but still.  That's my favorite part.

[kpaul]

10 hours ago, J0nathan225 said:

semi related question: does the Lasar cowl closure require repositioning the oil cooler?

no, it just closes off the bottom of the guppy mouth.

[JohnB]

On 8/16/2018 at 10:02 AM, MIm20c said:

I’m curious if members like @JohnB are getting similar TAS between the Aspen and TXI sitting side by side?

From my recollection, the GS on my Txi and my Aspen are essentially identical. IAS is identical,  the TAS is only different if I didn't change the barometer setting to match that of my Txi, but when i do that's the same too. the only thing different I have noticed is that the aspen displays an OAT, where as the Txi displays some other three letter abbrev representing some variant of air temperature (one of these days ill look it up), which are different numbers.

Ill look next flight to see if there is even a minute difference but from my memory, GS is pretty much the same number on the Aspen and the TXi.

[Immelman]

You all are going to hate me for this: 5 knots doesn't matter. Save your money, buy avgas, use your plane, quit worrying about true airspeed.

I fly at 450 knots for a living..... when its a long day and you're tired, that's still too slow!

Enjoy your Mooney, enjoy the view outside, the freedom of part 91 flight in your own airplane. Screw the groundspeed. Even on a long trip, that 5 knots won't mean much depending on how long it takes you to dilly-dally to get the airplane off the ground or put away.

[Mooneymite]

3 hours ago, Immelman said:

You all are going to hate me for this: 5 knots doesn't matter. Save your money, buy avgas, use your plane, quit worrying about true airspeed.

Heresy! 

How did this guy get to be on MS?  He is goring a sacred ox!

Next thing he'll be telling us is that the 5 minutes a pilot saves by choosing a quicker runway is the same as 5 minutes saved in the air.  

And only 450Kts?  That's barely .80.

[jetdriven]

On 8/16/2018 at 11:15 AM, MBDiagMan said:

Whoops!  I didn’t notice the TAS next to it.  On the 430, the TAS display is nothing more than a calculator.  You could enter whatever numbers you choose to obtain whatever TAS.  Hopefully the Aspen is more automated than that.

It doesn’t know the difference between CAS and IAS for example. That matters about 2 knots or so. 

[Dave Morris]

Hey, why doesn't someone organize a fly-in whose primary purpose is to conduct, not a "race", but a "performance run", where the aircraft take off in reverse alphabetical order (K-J-G-F-E-C-B-A) to fly a triangular course with observers at each corner, and each "contestant" entering all of their speed factors into a big spreadsheet, so we can finally see what a reversed brake cylinder with flap seals and landing light fairing and a fresh wax job with mouse milk in cylinder #3 will actually do to increase speed, and we won't have these endless conjectures.

Anybody got any experience organizing a rally?

 

[Hank]

2 hours ago, Dave N1960 said:

Anybody got any experience organizing a rally?

 

Dave! Long time no post . . . .

Can't vouch for organizing, but there are several experienced rally pilots here. Maybe they can pool their knowledge and put one on.

[MikeOH]

This thread prompted me to take a 'speed run' flight today.  I attempted to be as scientific as possible (criticize away!), here are the conditions, methodology, and data:

Aircraft: 1970 M20F,  Mods: Lower cowl closure, 201 windshield, flap, aileron, rudder, elevator gap seals, dorsal fin mod, PowerFlow exhaust, brake rotation. NOT freshly waxed

Test weight: 2237 +10/-20 pounds  (uncertainty in 'stuff' in cabin, plus fuel burn during test)

OAT = 78 F. (G3 Insight). RH = 40%. (I used an online calculator to determine the surface RH based on the temp/dew point at my departure airport and assumed the same RH at altitude where the OAT was 78 F as I had no way to determine dew point or RH directly.  I do not know what error this assumption introduced)

Pressure altitude = 6700 (I was trying, unsuccessfully to get a DA = 10,000). DA = 9,600 based upon PA, temp, and RH.

I used the GPS method described by Prof. David Rogers (Google "horseshoe method") which is completely independent of wind speed and direction and requires flying three legs of 90 degrees heading change.  I stabilized for several minutes on each leg after the GPS speed no longer was changing.

Throttle: WOT.

RPM = 2500 +/-20 throughout test (Horizon digital tach).

FF leaned to 10.3 +/-0.1 gph. (Based on many fuel fills being accurate to 0.5 gallon vs. fuel totalizer this should be an accurate fuel flow)

Drum roll, please.....

TAS = 168.4 mph

[jetdriven]

That’s a very accurate method of measuring speed. 

[David Lloyd]

Like what MikeOH did, The '65 C POH performance charts are pretty basic: Standard atmosphere, 2200 pounds, full fuel, pilot, and what seems to be a best power mixture. Let's use 7500' pressure altitude, light weight, GPS "horseshoe method speed, 2500 RPM and mixture to go as fast as possible.  List your mods, we could make charts for the C, E, F.

[ArtVandelay]

Like what MikeOH did, The '65 C POH performance charts are pretty basic: Standard atmosphere, 2200 pounds, full fuel, pilot, and what seems to be a best power mixture. Let's use 7500' pressure altitude, light weight, GPS "horseshoe method speed, 2500 RPM and mixture to go as fast as possible.  List your mods, we could make charts for the C, E, F.

Need to use DA, otherwise you northerners will be faster.

[Stephen]

For what it is worth this is a data point for an m20F, pause the video to see specific indications ...fuel flows and indicated speed and temps (scenery is over Lake of the Ozarks on my way home from to MO from AR.

 

 

 

 

[0TreeLemur]

On 8/29/2018 at 10:10 PM, MikeOH said:

This thread prompted me to take a 'speed run' flight today.  I attempted to be as scientific as possible (criticize away!), here are the conditions, methodology, and data:

Aircraft: 1970 M20F,  Mods: Lower cowl closure, 201 windshield, flap, aileron, rudder, elevator gap seals, dorsal fin mod, PowerFlow exhaust, brake rotation. NOT freshly waxed

Test weight: 2237 +10/-20 pounds  (uncertainty in 'stuff' in cabin, plus fuel burn during test)

OAT = 78 F. (G3 Insight). RH = 40%. (I used an online calculator to determine the surface RH based on the temp/dew point at my departure airport and assumed the same RH at altitude where the OAT was 78 F as I had no way to determine dew point or RH directly.  I do not know what error this assumption introduced)

Pressure altitude = 6700 (I was trying, unsuccessfully to get a DA = 10,000). DA = 9,600 based upon PA, temp, and RH.

I used the GPS method described by Prof. David Rogers (Google "horseshoe method") which is completely independent of wind speed and direction and requires flying three legs of 90 degrees heading change.  I stabilized for several minutes on each leg after the GPS speed no longer was changing.

Throttle: WOT.

RPM = 2500 +/-20 throughout test (Horizon digital tach).

FF leaned to 10.3 +/-0.1 gph. (Based on many fuel fills being accurate to 0.5 gallon vs. fuel totalizer this should be an accurate fuel flow)

Drum roll, please.....

TAS = 168.4 mph

I thought that was crazy fast and I gotta do some serious mods, until I re-read and noticed your speed unit was mph.  Converted to kts, your TAS is a very ballparkish for a pre-J Mooney 146 kt.

[MikeOH]

16 minutes ago, Fred_2O said:

I thought that was crazy fast and I gotta do some serious mods, until I re-read and noticed your speed unit was mph.  Converted to kts, your TAS is a very ballparkish for a pre-J Mooney 146 kt.

You are correct; and, I was a bit disappointed to find it pretty much the book number.

However,....and I wasn't going to admit this until now,....I realized a day later that I didn't CLOSE THE COWL FLAPS!!!

Not sure what that took away, but I'm going to have to run the test again; or, more likely, just stabilize at the same power setting, at the same DA, note the speed...then close the cowl flaps, and look at the rise.  Then, just add that to my 168.4 mph number.

[0TreeLemur]

13 hours ago, MikeOH said:

You are correct; and, I was a bit disappointed to find it pretty much the book number.

However,....and I wasn't going to admit this until now,....I realized a day later that I didn't CLOSE THE COWL FLAPS!!!

Not sure what that took away, but I'm going to have to run the test again; or, more likely, just stabilize at the same power setting, at the same DA, note the speed...then close the cowl flaps, and look at the rise.  Then, just add that to my 168.4 mph number.

After climbing from 9,500 to 11,500 on one leg of our recent trip around the Wild West I leveled out, trimmed, and leaned the mixture.  After a few minutes I realized that I hadn't closed the cowl flaps.  My thought was "AHA! we'll really go fast now!".   I closed them and really couldn't detect the increase within the precision of the AS indicator and noise of the GS reading on the GPS...   Disappointing.   I'll  be interested to hear how that changes the results in in your next test.  Looking at the  Flight aware trace of that flight leg, I think I closed them about 54 minutes into the trip after I climbed from 9,500 to 11,500.  The speed plot really shows no difference in reported GS.  That result suggests that closing cowl flaps at 11,500' (DA about 13 kft) in a C with a LASAR lower cowl mod. represents a sub-kt speed increase.

[Raptor05121]

On 8/25/2018 at 11:05 AM, Immelman said:

 Even on a long trip, that 5 knots won't mean much depending on how long it takes you to dilly-dally to get the airplane off the ground or put away.

 

It is so true. I followed my friend down to South Florida to get his Comanche 260 painted. I took off first, he followed 2-3 minutes behind me. We both leveled off at 8,500 and I watched my ADS-B as he slowly inched past me with him having 20 knots on me. I was 145kts over the ground, he was doing 165kts. After we traveled the 130 miles to Okeechobee, he landed 2-3 minutes before I did.  20 knots seems like a lot of speed, but overall, 4-6 minutes is a pittance in the grand scheme that is GA flying. This is especially resonant to Cherokee-owning friends who are looking at spending several AMUs for speed pants that claim a measly 2-3 knots.

[Hank]

1 hour ago, Fred_2O said:

After climbing from 9,500 to 11,500 on one leg of our recent trip around the Wild West I leveled out, trimmed, and leaned the mixture.  After a few minutes I realized that I hadn't closed the cowl flaps.  My thought was "AHA! we'll really go fast now!".   I closed them and really couldn't detect the increase within the precision of the AS indicator and noise of the GS reading on the GPS...   Disappointing.   I'll  be interested to hear how that changes the results in in your next test.  Looking at the  Flight aware trace of that flight leg, I think I closed them about 54 minutes into the trip after I climbed from 9,500 to 11,500.  The speed plot really shows no difference in reported GS.  That result suggests that closing cowl flaps at 11,500' (DA about 13 kft) in a C with a LASAR lower cowl mod. represents a sub-kt speed increase.

Maybe that's why cowl flaps in later Cs, like my 1970 model, are fixed . . . .

[Mooney-Mark]

On 8/29/2018 at 11:10 PM, MikeOH said:

This thread prompted me to take a 'speed run' flight today.  I attempted to be as scientific as possible (criticize away!), here are the conditions, methodology, and data:

Aircraft: 1970 M20F,  Mods: Lower cowl closure, 201 windshield, flap, aileron, rudder, elevator gap seals, dorsal fin mod, PowerFlow exhaust, brake rotation. NOT freshly waxed

Test weight: 2237 +10/-20 pounds  (uncertainty in 'stuff' in cabin, plus fuel burn during test)

OAT = 78 F. (G3 Insight). RH = 40%. (I used an online calculator to determine the surface RH based on the temp/dew point at my departure airport and assumed the same RH at altitude where the OAT was 78 F as I had no way to determine dew point or RH directly.  I do not know what error this assumption introduced)

Pressure altitude = 6700 (I was trying, unsuccessfully to get a DA = 10,000). DA = 9,600 based upon PA, temp, and RH.

I used the GPS method described by Prof. David Rogers (Google "horseshoe method") which is completely independent of wind speed and direction and requires flying three legs of 90 degrees heading change.  I stabilized for several minutes on each leg after the GPS speed no longer was changing.

Throttle: WOT.

RPM = 2500 +/-20 throughout test (Horizon digital tach).

FF leaned to 10.3 +/-0.1 gph. (Based on many fuel fills being accurate to 0.5 gallon vs. fuel totalizer this should be an accurate fuel flow)

Drum roll, please.....

TAS = 168.4 mph

That' a pretty impressive TAS Mike!

[0TreeLemur]

Just now, Hank said:

Maybe that's why cowl flaps in later Cs, like my 1970 model, are fixed . . . .

Hank, are they the same size, but fixed in some open position?   Or are they spayed and neutered ?

[Mooney-Mark]

40 minutes ago, Raptor05121 said:

It is so true. I followed my friend down to South Florida to get his Comanche 260 painted. I took off first, he followed 2-3 minutes behind me. We both leveled off at 8,500 and I watched my ADS-B as he slowly inched past me with him having 20 knots on me. I was 145kts over the ground, he was doing 165kts. After we traveled the 130 miles to Okeechobee, he landed 2-3 minutes before I did.  20 knots seems like a lot of speed, but overall, 4-6 minutes is a pittance in the grand scheme that is GA flying. This is especially resonant to Cherokee-owning friends who are looking at spending several AMUs for speed pants that claim a measly 2-3 knots.

Yes, but speed "feels so good"!

[Hank]

7 minutes ago, Fred_2O said:

Hank, are they the same size, but fixed in some open position?   Or are they spayed and neutered ?

I've got a picture showing how far they open somewhere. This is what I can find right now. 

They are the same size on both sides of the nose gear.