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Takeoff Distance Table 1st Gen Ovation


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Mark,

Yes, they have...

See if you can find the Other Patrick... the one who really knows how to calculate T/O distance for His O...

Invite @patrickf

He posted his spreadsheet and the ability to use it like an app in an idevice a while ago...

It would be great if every Mooney could have such great functionality... in an App.

 

I mention this quite often, because the first Patrick didn’t have the numbers for his M20J one day... and the flight ended too soon...

DA, WnB, available runway length... a little knowledge is a powerful thing...

 

Last I conversed with PatrickF the spreadsheet was still being tested personally...  it might be really helpful having a CFI collect additional data. Got CloudAhoy and a WAAS source with that? 

Best regards,

-a-

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8 hours ago, carusoam said:

Mark,

Yes, they have...

See if you can find the Other Patrick... the one who really knows how to calculate T/O distance for His O...

Invite @patrickf

He posted his spreadsheet and the ability to use it like an app in an idevice a while ago...

It would be great if every Mooney could have such great functionality... in an App.

 

I mention this quite often, because the first Patrick didn’t have the numbers for his M20J one day... and the flight ended too soon...

DA, WnB, available runway length... a little knowledge is a powerful thing...

 

Last I conversed with PatrickF the spreadsheet was still being tested personally...  it might be really helpful having a CFI collect additional data. Got CloudAhoy and a WAAS source with that? 

Best regards,

-a-

I have his app. Interesting, but I do this for multiple types and am more interested in the underlying data. Yeah, I can do it myself, but I'm lazy. :D I forgot he posted the spreadsheet itself. I'll have to look for it. Thanks,

Yes, I have Cloud Ahoy and WAAS capability, but I'm not trying to "roll my own" numbers. Just the POH numbers in table form for easier reference.

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Mark,

The reason I point towards this app version...

1) It shouldn’t be “roll your own...” the data is there already.

2) It should result in exactly the same numbers your finger being dragged accross a paper chart should give...

3) It should eliminate any fat finger errors... (a reference to the London Whale who lost a few billion dollars...)

 

The reason I suggest comparing to a WAAS source...

1) I have no idea how well PatrickF executed the math... It is possible to have some error?

2) Having a CFI, with excellent data collection skills, and the hardware... should be able to add validity to the system.

 

Having a modern society, pulling tiny paper charts, out of an aged and ragged binder... is screaming for improvement.

Having the SAME data, available from your pocket, at any time... will help people comply with the laws of physics...

 

Some people are not using these charts for some reason...

Around MS... We have gotten people to discuss DA calculations openly.  This is the next step.

 

I picture a future that has electronic ignition, electronic calculators, and a Guy named Jim loudly proclaiming we can do better... :)

 

Our engine technology May be left over from the ice age.... but, our critical data handling should have taken at least one step forward, at least once, in the new millenium...

 

So grab that idevice, crank out some T/O data, compare to actual reality, report the success/failure...

 

Mark, If I understood correctly... you were asking for a chart to get this same data.... to handle all the possibilities it would be a book of charts...

 

I get the feeling... ‘somebody should do something’....   PatrickF did exactly that....

 

Lets get people to use the data... more often...

Lets make it so easy to use the data... we will use it because we can...

Lets find out where and when the data doesn’t work....

Let’s find out why our plane doesn’t match the fleet average... (mechanical or procedural?)

Lets eliminate the human error that took the life of MS’s Patrick....

Lets demonstrate PatrickF’s data works for the O...  then expand it to every Mooney on and off the planet...

 

I think we may be onto something...

Best regards,

-a-

 

 

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Understand completely. But here's  where I'm coming from. Once beyond some ballpark numbers, striving for super accuracy is pretty close a fool's  errand. My goal is "easy to calculate than the graph," not "get me exact numbers".

If you look at the sample calculation in the first gen Ovation manual, it comes up with 1550' ground roll and 2900' over the proverbial 50' obstacle at 17 degrees C with a 5 kt tailwind at 3250 lbs.  I don't care how good we are at graphs, there is no practical way on even a good copy to be sure one has selected 17 degrees, followed the wind line perfectly (since the angle itself changes with altitude, and then be certain that 1550 isn't actually 1600, at least not without breaking down the graph into its component data. That, of course, is still assuming out airplanes are in perfect factory condition and we, as pilots, are nailing every airspeed to the knot. And don't forget: we have also calculated the head and crosswind components to the knot and the winds are absolutely steady. 

And that sample calculation is an easy one. 5,000' has its own line. Make the numbers different, say 6500 pressure altitude, and we can have some fun. The performance numbers have, to me, always been fudgy. Something you want to calculate, but with an appreciable safety margin. Trying for exactitude is like trying to measure a football field with a micrometer. 

BTW, Patrick's spreadsheet gives us 1521' and 2907' for that sample calculation. If he's really broken down the graph, he's probably right, but IMO it doesn't matter. I like what he did. A lot. I'm not poo-poohing it. Actually, the numbers I'm looking for are to put in a spreadsheet I've been using with multiple makes and models over the past 10 years or so. But it is subject to the same practical errors as the graph. 

It's one of the reasons I've always preferred the Cessna tables to the performance graphs. Just more realistic and much easier to use..

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1 hour ago, midlifeflyer said:

It's one of the reasons I've always preferred the Cessna tables to the performance graphs. Just more realistic and much easier to use..

I sure don't miss the speeds and ranges of my former Cessna, but I thought the performance tables were way easier to use.  And if my numbers got close to bumping into the next cell, it was a sign....

High resolution is both useful and satisfying, but I miss those tables.

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What I find challenging...

We often use two adjustments... one in the calculation, and the next for safety...

By the time we add two adjustments... the T/O roll is calculated out to 4k’ adding a typical factor of safety gets us 6k’...

Starting with the tight numbers provided, that are laws of physics based... doesn’t need to be so fuzzy...

Sooner or later, an O driver wants to use a 2k’ runway...

Start with the exact numbers, then add a single factor of safety...

 

I was pleasantly surprised to see how well my plane conforms to the data... provided by Rocket Engineering...

T/O roll is essentially a 0 to 65 kias drag race... mostly a temp, altitude and weight dependent calculation... F=ma :)

 

crank in the numbers, get the exact detail, then use the appropriate factor of safety...

 

Then have the back up numbers memorized...

An O1 can be off the ground in 1200’ lightly loaded, cool day...

An O3 can be off the ground in 800’ under the same conditions...

 

one thing for sure... a chart is better than a list... and a list is better than not checking the data at all...

if it gets too hard/complicated, people stop using the data....

 

I’m trying to promote making it easier and sensible to get real data...   oddly enough, the WAAS gps actually measures accurately to the foot... might as well start the calculations with that level of accuracy...

 

 

The factor of safety can also use some update based on available Mooney MS experience...

 

I lean more towards science and technology for this... my primary training left a few topics not very well covered....

Best regards,

-a-

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17 minutes ago, Two Oh One said:

I sure don't miss the speeds and ranges of my former Cessna, but I thought the performance tables were way easier to use.  And if my numbers got close to bumping into the next cell, it was a sign....

High resolution is both useful and satisfying, but I miss those tables.

That's basically what I am looking for. The Mooney graph converted to Cessna-style tables.

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With all the apps floating around for anything in the world, wouldn't you think that someone would have designed a program that asks for model, weight, temperature, airport altitude, wind speed, wind direction, runway direction, and obstacle height. Then it would spit out takeoff and landing distances.                                            

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6 hours ago, carusoam said:

T/O roll is essentially a 0 to 65 kias drag race... mostly a temp, altitude and weight dependent calculation... F=ma :)

When I repainted the numbers at my previous airport, I took the opportunity to compare acceleration between my hot rod 5-speed Honda Accord and my M20-C. Tires spinning, redlining and speed shifting, I was about 60 mph in the Honda by the point the Mooney  usually lifts off, and I pull the yoke passing through 70 mph.

At least my old Owners Manual doesn't require squinting or magnification to read the Takeoff Distances. On the other hand, it doesn't provide much detail, either. But I was based my first seven years at a 3000' field with tall trees off the preferred runway end, and visited a nearby 2000'grass strip (2 people, half tanks limit) with no problems. Ain't many places a Mooney can't go.

Screenshot_20190221-212602.thumb.jpg.5068b916492a2e6017be32b3d7779a73.jpg

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11E9F07B-2F9B-47EA-BBCB-2BD9124E48ED.thumb.jpeg.c3ba101c10d32845ad246fe1176ce8ea.jpeg

 

That is the type of table Mark is probably looking for... @midlifeflyer

The long body has a complex four part graph that includes... actually two graphs... (hard and grass surfaces)

  • all possible OATs
  • all possible MGTWs
  • Head winds and tailwinds from 0 to 20...
  • all obstacles from 0 to 50’ tall...

The graph is so tiny, following it with a finger becomes a bit silly....

in the accompanying pic...  that is an ordinary finger on the Take-off Distance for a Grass Surface for an O1...

Having an official resource on a smart phone would be brilliant...

Wondering what @mike_elliott thinks about this method of deriving book numbers for take-of and obstacle clearance...

If this makes sense to Mike... we may have a method of refining and taking the idea a bit further...

Best regards,

-a-

 

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1 hour ago, Hank said:

When I repainted the numbers at my previous airport, I took the opportunity to compare acceleration between my hot rod 5-speed Honda Accord and my M20-C. Tires spinning, redlining and speed shifting, I was about 60 mph in the Honda by the point the Mooney  usually lifts off, and I pull the yoke passing through 70 mph.

Yeah, but how much distance did it take to get your Honda Accord over the 50' obstacle? 

B)

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Sense the the steering wheel bend as the runway end approaches....  :)

I got a ride in one of those Teslas.... 0 to wow! Going down the runway....

It is an amazing heavy four seater with gobs of torque... something that electric motors are good at...

Best regards,

-a-

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16 hours ago, midlifeflyer said:

That's basically what I am looking for. The Mooney graph converted to Cessna-style tables.

Guys,

just caught up on this one. Thanks for the heads up @carusoam

@midlifeflyer I am happy to generate a set of "Cessna style" tables. Will be pretty easy to pull automatically out of my sheet, and you are right  they would be useful.

My sheet just does the calcs on digitised versions of the charts, and draws over to confirm visually that results make sense. It is at least as accurate as doing it with a pencil, or thumb.

I am working my way through the various models but am way behind on my promise to complete the set - dam work.

I've just looked at the POHs I have and my M20J one has the table version rather than the chart. I've attached.

Is it an earlier version ? 

PatrickF

M20J_TO.jpg

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3 hours ago, patrickf said:

Guys,

just caught up on this one. Thanks for the heads up @carusoam

@midlifeflyer I am happy to generate a set of "Cessna style" tables. Will be pretty easy to pull automatically out of my sheet, and you are right  they would be useful.

My sheet just does the calcs on digitised versions of the charts, and draws over to confirm visually that results make sense. It is at least as accurate as doing it with a pencil, or thumb.

Looking at your sheet I figured that's probably what you did. That's why I'm so impressed!  

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On 2/22/2019 at 7:04 AM, carusoam said:

 

I’m trying to promote making it easier and sensible to get real data...   oddly enough, the WAAS gps actually measures accurately to the foot... might as well start the calculations with that level of accuracy...

 

 

I like where you are heading here @carusoam - start with the book numbers and check against reality given the info we now capture.

It was something I remember doing with the instructor in the C150 on about my 4th hour - check short field takeoff against the book. We used the cross runways and taxi entrances as the check points. Having said that a 150, 2 up, in summer in Canberra at 1800 ft elevation gave us plenty of time to check the lift off point !

You've prompted me to check the M20R against the book more carefully. We have a cyclone off the coast so no flying this weekend but I've done a quick desktop check.

Our home strip YCAB only has 250m (780ft) of tar before the grass. If I'm one up and only 30 gal of fuel I can just get the wheels off before the tar ends (without doing a static full power, release brakes etc. short field takeoff).

The book number on a typical day with 5kts of head is 628 ft. Given that I probably waste 40 ft rolling on and 50 ft with the rolling "soft start" the book numbers look close but a bit wishful - you'd want a good margin on these.

PatrickF

YCAB_12.jpg

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