Hi mate from Australia, I have to say your Channel is really something else, the learning & understanding flight dynamics take aways have to be an absolute winner on You Tube. I dont think any one else explains this stuff quite as effectively as you as they always rush it or gloss over the theory side of things. Great to see the skywagon in action. Thank You
HAHA! I see you're a Friends fan. Thanks, I appreciate it. TH-cam and comments are almost the next best thing. I'll be at Sun-n-Fun and Oshkosh this year... maybe we can meet up and talk flying stuff!
This is interesting I’ve got a 79 185 stock wing. POH lists different speed for best glide with different weights. So it seems to me I should give this a test.
Great stuff! I would like to know how the 1.3xx ratio was derived (or reference to the pieces so I can derive it). I may add the effect of 10, 20, and 30kt headwind and tailwind to the spreadsheet as they have greater proportional effect on slow airspeeds than fast. There isn't much practical in calculating the ideal for every combination, and that would need a more complete glide-performance curve anyway, but it would be handy to know a rough approximation of the crossover between the 3 configurations/speeds. eg Just when does it become favorable(in your example airplane) to switch from best flaps10 glide, to best clean glide(headwind), or favor min sink(tailwind).
I’m not sure I understand the question. How I determined Best Glide/Min Sink in this C180 was by experimenting with descent rates. If that’s the question- empirically is the answer.
Love your videos Scott. Just curious you said you are not going to put an angle of attack indicator on your plane. Are you against them, or do you really not feel you need it?
No, I love AoA gages. I'm pretty sure I mentioned why I don't like them in GA. All GA AoA gages except for one that I know if use differential pressure and not a vane. Differential pressure is an approximation and the error rate is greatest at high AoA. So, not for me. I wish vane based AoA was available.
Great video Scott! I have a 1964 C185 (with no glide info in the original POH). I've also recently did the same wing modifications that you have (WingX, Sportsman STOL, and VGs). I intend to go out and duplicate your flight test to approximate V min-sink and calculate V range. I downloaded the spreadsheet and have been building my own to match it. The formulae for the first section on V min-sink are straight forward conversions. I'm a bit stumped however on how you came up with the Predicted FPM sink rate for Vrange. The spreadsheet you have doesn't allow me to see the formulae in the cells. Can you provide some insight on how you backed into the predicted FPM numbers please?
Great to hear you are exploring your airplane! The FPM results were straight from my data collection and not the result of a formula. There has been a recent change in Excel presentation of formulas and I don't fully understand it... I've seen several errors, on what was previously a good formula/computation. The errors aren't large, but enough to cast some doubt on how this new software is doing the math. Time is a factor here to ferret that out. As in I don't have enough right now to figure it out.
@@FlyWirescottperdue Thanks for the quick reply. I'll gather the FPM sink rate info and airspeeds to determine best configuration for minimum sink as you've described. I'll then multiply the Vminimum sink by 1.316 to determine an approximate Vrange (best glide) configuration and airspeeds. That'll get me where I need to be. I was just curious because it appeared you developed some "Predicted" sink rates for best glide that you then later went out and verified. I'll let you know what I find. Excited to see the results of my investment in wing mods!
Just turn off sheet protection. In Libreoffice it is a checkbox in the tools menu. Then turn sheet protection back on and it will give a list of options, be sure to check "Allow users to: select protected cells." then you can read formulas but the cells are still write protected.
Great video. I've been wondering how best to do this after the modifications we've made to our '60 Skywagon with Sportsman and larger tires. Now I've got to go burn some fuel!
I have the same wing in my 185E as you do (Sportsman cuff, WingX extensions and Micro Aero VG’s), but with flap gap seals. I even have the Canadian exhaust shroud, which is very effective in cooling the engine during climbs on hot days, BTW. Tires are 8.50x6 with a 10” tailwheel. Even though I never explored Vg to the degree you have (I will), the wing performs noticeably better than a stock wing. The flap gap seals are really noticeable in a clean climb, descent and glide. My descent planning had to be adjusted slightly, because the airplane doesn’t want to slow down as quickly as it did without the flap gap seals and the cruise speed is quicker. There was no change (in my experience) in stall speeds before or after the seals, BTW. I am particularly sensitive to this, as I normally operate out of a 1400’ runway at 5400’ MSL. If the flap gap seals interfered with that particular performance requirement they would be gone. I really like the added cruise speed they yield along with the speed benefit of the electronic ignition (ignition advance happens below 24” MAP, which is shortly after every takeoff in my part of the world). It all adds up, especially when cruising lean of peak. I’m going to run through what you did. Nice job! The glide performance with flaps 10 is intriguing to me.
Thanks! I am anxious to hear what you find out. I'm going to post the spreadsheet to compute all this on my website in the blog section, if that helps.
FlyWire- scott perdue I’ll let you know. I see you did some work for NASA. I did, too. Flew the DC-8 and 747SP “SOFIA” as a contractor out of Dryden FRC until 2015 after retiring from the airline. We need to compare notes.
@@mannypuerta5086 I didn't get to do a flying program. For NASA I worked on GPS guided flight paths, repeatable within a 10' error. A precursor to today's autonomous drones. We also worked out rules for drones operating in formation... they did that with F-18's and the pilots just watched. My main role was managing subs, refereeing ideas and putting the briefing together. This was in the early days of piezio-electric accelerometers (MEMS).... that was the fun part.
FlyBoy- I'll put the Excel Spreadsheet up on my Website Blog today or tomorrow: flywire.online . So, you can run the test yourself. I'd love to know what the L-19 does.
Cool channel, excellent experiments, worthwhile knowledge to store in glove box. I'm not a flyer... more of a wind tunnel / fluid dynamics kind of guy... but I wondered how a severely forward or backward CG... might effect these experiment findings. Maybe insignificant, maybe not. I wonder if a pilot who really "feels his plane"... could quickly "derive" best-glide... via "seat-of-the-pants" feel. Maybe engine fail with dead gauges or cockpit full of smoke. One wonders... how similar math-formula best-glide... compares to "seat-of-the-pants" (I know my plane like the back of my hand, no matter what its cargo)... best glide. :) Then let's test it again, but with pontoons. :) Do SOME brands/types of planes... sort-of seek-out their own best-glide... with hands-off dead stick? I've herd that 150's are that way... difficult to make land... sorta need to lasso a tree and winch yourself to the runway... cuz it loves to fly so much. :)
Larry- thanks for watching! Interesting comments. To some degree flying is a 'seat-of-the-pants' activity. But when you need to be accurate, the human somatosensory organs fill in the blanks with spurious information, essentially lying to you. There are times you have to use your instruments, doesn't matter how good you are.
Yeah, I understand and agree. These "preventative measure" tests give a rather handy emergency assistant. It can be plugged-in rather fast... and buy a pilot extra time to weigh/pick contingencies. It should maximize fuel usage in many situations, too. Love it. I'm still thinking about weight/cg, though. We are pitching for best-glide-speed, right? When weight/cg varies, pitch-angle needed to maintain best glide-speed... will vary, too, it seems. SO... we don't really care about best-pitch-angle, right? That could change from trip to trip, depending upon loads. We care about knowing that best-glide-speed... and always pitching for speed, no matter the load. Does that sound right? hehe (sorry) (so many questions) :)
@@wingleberry1 Weight does indeed affect Glide Speed, but the reality is that the delta, or spread, in speeds is not great. If it is a true emergency I advocate having a 'Go To' speed, we are humans and in a real emergency you won't have a lot of brain bytes left to deal with added complexity. I think its best to simplify things rather than make them more complex. Moreover, there is no simple reference for fine tuning pitch angle-- I sure don't want you looking at the attitude indicator during an engine out. Look outside and land the plane.
Nod, yeah, when low altitude, that makes sense. But if you have altitude, or have an engine fail above the cloud layer... you want to get into best glide as soon as possible... so you get maximum number of restart attempts and fuel valve checking, etc. Even after you break thru cloud layer, you want max glide... to give max decision-making time, yes? Say, at 3000 dead engine, there's still no hurry to get onto the ground (in a 182-like floater), right? I guess it all depends upon the type of terrain beneath, and a hundred other factors. Just thinkin. Let's say, under empty load... 10-flaps is nice. In emergency dead-engine, with family and luggage on-board... pilot might think "I need best glide NOW for max thinking/restart options." So they apply flaps-10... and don't re-visit that decision. But really, because of different weight/cg than testing day, pilot needs 15-20 flaps for best-glide in the emergency. Has his/her "pre-tests"... fooled them into thinking that they are in good shape with 10-flaps... when actually... they are hurting the emergency best-glide... because they forgot about the load differences? hehe I dunno. Scott, it's very very kind of you... to talk with me... I'm totally honored... thank you. Too good. I'm not experienced enough in real flying... to know what/how to ask things... sorry. Darned interesting, though. I bet you never expected your best-glide/min-sinkvideo/tests... would generate so much continued curiosity. :)
"at 3000 dead engine, there's still no hurry to get onto the ground (in a 182-like floater)" (There, I mean you still have what? About 90 seconds to make a landing game-plan? Many factors to that, and I could be WAY off).
Hi mate from Australia, I have to say your Channel is really something else, the learning & understanding flight dynamics take aways have to be an absolute winner on You Tube. I dont think any one else explains this stuff quite as effectively as you as they always rush it or gloss over the theory side of things. Great to see the skywagon in action. Thank You
Thanks a bunch Equal, I appreciate it!
Man I wish I had a mentor pilot like you in my flying club. Your passion is unbelievable and only overshadowed by your humble flying knowledge.
HAHA! I see you're a Friends fan. Thanks, I appreciate it. TH-cam and comments are almost the next best thing. I'll be at Sun-n-Fun and Oshkosh this year... maybe we can meet up and talk flying stuff!
Heck yeah, I’m planning on flying in for that. Hope to see the bonanza there.
As always, great material! My C-180 is down for annual but when we finish I'm going out and doing this. Have a great day Scott!
Great Information on Best Glide speed. Fantastic to see you demonstrate this ! Loved it ! from Australia
This is interesting I’ve got a 79 185 stock wing. POH lists different speed for best glide with different weights. So it seems to me I should give this a test.
Great stuff! I would like to know how the 1.3xx ratio was derived (or reference to the pieces so I can derive it).
I may add the effect of 10, 20, and 30kt headwind and tailwind to the spreadsheet as they have greater proportional effect on slow airspeeds than fast. There isn't much practical in calculating the ideal for every combination, and that would need a more complete glide-performance curve anyway, but it would be handy to know a rough approximation of the crossover between the 3 configurations/speeds. eg Just when does it become favorable(in your example airplane) to switch from best flaps10 glide, to best clean glide(headwind), or favor min sink(tailwind).
I’m not sure I understand the question. How I determined Best Glide/Min Sink in this C180 was by experimenting with descent rates. If that’s the question- empirically is the answer.
Love your videos Scott. Just curious you said you are not going to put an angle of attack indicator on your plane. Are you against them, or do you really not feel you need it?
No, I love AoA gages. I'm pretty sure I mentioned why I don't like them in GA. All GA AoA gages except for one that I know if use differential pressure and not a vane. Differential pressure is an approximation and the error rate is greatest at high AoA. So, not for me. I wish vane based AoA was available.
Great video Scott! I have a 1964 C185 (with no glide info in the original POH). I've also recently did the same wing modifications that you have (WingX, Sportsman STOL, and VGs). I intend to go out and duplicate your flight test to approximate V min-sink and calculate V range. I downloaded the spreadsheet and have been building my own to match it. The formulae for the first section on V min-sink are straight forward conversions. I'm a bit stumped however on how you came up with the Predicted FPM sink rate for Vrange. The spreadsheet you have doesn't allow me to see the formulae in the cells. Can you provide some insight on how you backed into the predicted FPM numbers please?
Great to hear you are exploring your airplane! The FPM results were straight from my data collection and not the result of a formula. There has been a recent change in Excel presentation of formulas and I don't fully understand it... I've seen several errors, on what was previously a good formula/computation. The errors aren't large, but enough to cast some doubt on how this new software is doing the math. Time is a factor here to ferret that out. As in I don't have enough right now to figure it out.
@@FlyWirescottperdue Thanks for the quick reply. I'll gather the FPM sink rate info and airspeeds to determine best configuration for minimum sink as you've described. I'll then multiply the Vminimum sink by 1.316 to determine an approximate Vrange (best glide) configuration and airspeeds. That'll get me where I need to be. I was just curious because it appeared you developed some "Predicted" sink rates for best glide that you then later went out and verified. I'll let you know what I find. Excited to see the results of my investment in wing mods!
Just turn off sheet protection. In Libreoffice it is a checkbox in the tools menu. Then turn sheet protection back on and it will give a list of options, be sure to check "Allow users to: select protected cells." then you can read formulas but the cells are still write protected.
This was a really great video, much appreciated
You would get a longer glide without flaps, more time to select a landing spot.
Your comments are great! You would sound and be more understandable if you could put a foam cover over the mike!
Great video. I've been wondering how best to do this after the modifications we've made to our '60 Skywagon with Sportsman and larger tires. Now I've got to go burn some fuel!
Glad I could provide you with an excuse to fly;)!
I have the same wing in my 185E as you do (Sportsman cuff, WingX extensions and Micro Aero VG’s), but with flap gap seals. I even have the Canadian exhaust shroud, which is very effective in cooling the engine during climbs on hot days, BTW. Tires are 8.50x6 with a 10” tailwheel.
Even though I never explored Vg to the degree you have (I will), the wing performs noticeably better than a stock wing. The flap gap seals are really noticeable in a clean climb, descent and glide. My descent planning had to be adjusted slightly, because the airplane doesn’t want to slow down as quickly as it did without the flap gap seals and the cruise speed is quicker.
There was no change (in my experience) in stall speeds before or after the seals, BTW. I am particularly sensitive to this, as I normally operate out of a 1400’ runway at 5400’ MSL. If the flap gap seals interfered with that particular performance requirement they would be gone. I really like the added cruise speed they yield along with the speed benefit of the electronic ignition (ignition advance happens below 24” MAP, which is shortly after every takeoff in my part of the world). It all adds up, especially when cruising lean of peak.
I’m going to run through what you did. Nice job! The glide performance with flaps 10 is intriguing to me.
Thanks! I am anxious to hear what you find out. I'm going to post the spreadsheet to compute all this on my website in the blog section, if that helps.
FlyWire- scott perdue I’ll let you know. I see you did some work for NASA. I did, too. Flew the DC-8 and 747SP “SOFIA” as a contractor out of Dryden FRC until 2015 after retiring from the airline. We need to compare notes.
@@mannypuerta5086 I didn't get to do a flying program. For NASA I worked on GPS guided flight paths, repeatable within a 10' error. A precursor to today's autonomous drones. We also worked out rules for drones operating in formation... they did that with F-18's and the pilots just watched. My main role was managing subs, refereeing ideas and putting the briefing together. This was in the early days of piezio-electric accelerometers (MEMS).... that was the fun part.
I'm curious...did you play with prop pitch while calculating min sink? Thanks.
Yes, I think I talked about that. Pull the prop back!
@@FlyWirescottperdue I binged a bunch of your vids and I lost track. Thanks.
@@Joe_Not_A_Fed No worries Joe! Thanks for watching!
Enjoyed your video
What is the equation, do you have the spreadsheet available? I would love to figure this out on my L-19 Birddog.
FlyBoy- I'll put the Excel Spreadsheet up on my Website Blog today or tomorrow: flywire.online . So, you can run the test yourself. I'd love to know what the L-19 does.
Cool channel, excellent experiments, worthwhile knowledge to store in glove box. I'm not a flyer... more of a wind tunnel / fluid dynamics kind of guy... but I wondered how a severely forward or backward CG... might effect these experiment findings. Maybe insignificant, maybe not. I wonder if a pilot who really "feels his plane"... could quickly "derive" best-glide... via "seat-of-the-pants" feel. Maybe engine fail with dead gauges or cockpit full of smoke. One wonders... how similar math-formula best-glide... compares to "seat-of-the-pants" (I know my plane like the back of my hand, no matter what its cargo)... best glide. :) Then let's test it again, but with pontoons. :)
Do SOME brands/types of planes... sort-of seek-out their own best-glide... with hands-off dead stick? I've herd that 150's are that way... difficult to make land... sorta need to lasso a tree and winch yourself to the runway... cuz it loves to fly so much. :)
Larry- thanks for watching! Interesting comments. To some degree flying is a 'seat-of-the-pants' activity. But when you need to be accurate, the human somatosensory organs fill in the blanks with spurious information, essentially lying to you. There are times you have to use your instruments, doesn't matter how good you are.
Yeah, I understand and agree. These "preventative measure" tests give a rather handy emergency assistant. It can be plugged-in rather fast... and buy a pilot extra time to weigh/pick contingencies. It should maximize fuel usage in many situations, too. Love it. I'm still thinking about weight/cg, though. We are pitching for best-glide-speed, right? When weight/cg varies, pitch-angle needed to maintain best glide-speed... will vary, too, it seems. SO... we don't really care about best-pitch-angle, right? That could change from trip to trip, depending upon loads. We care about knowing that best-glide-speed... and always pitching for speed, no matter the load. Does that sound right? hehe (sorry) (so many questions) :)
@@wingleberry1 Weight does indeed affect Glide Speed, but the reality is that the delta, or spread, in speeds is not great. If it is a true emergency I advocate having a 'Go To' speed, we are humans and in a real emergency you won't have a lot of brain bytes left to deal with added complexity. I think its best to simplify things rather than make them more complex. Moreover, there is no simple reference for fine tuning pitch angle-- I sure don't want you looking at the attitude indicator during an engine out. Look outside and land the plane.
Nod, yeah, when low altitude, that makes sense. But if you have altitude, or have an engine fail above the cloud layer... you want to get into best glide as soon as possible... so you get maximum number of restart attempts and fuel valve checking, etc. Even after you break thru cloud layer, you want max glide... to give max decision-making time, yes? Say, at 3000 dead engine, there's still no hurry to get onto the ground (in a 182-like floater), right?
I guess it all depends upon the type of terrain beneath, and a hundred other factors. Just thinkin. Let's say, under empty load... 10-flaps is nice. In emergency dead-engine, with family and luggage on-board... pilot might think "I need best glide NOW for max thinking/restart options." So they apply flaps-10... and don't re-visit that decision. But really, because of different weight/cg than testing day, pilot needs 15-20 flaps for best-glide in the emergency. Has his/her "pre-tests"... fooled them into thinking that they are in good shape with 10-flaps... when actually... they are hurting the emergency best-glide... because they forgot about the load differences?
hehe I dunno. Scott, it's very very kind of you... to talk with me... I'm totally honored... thank you. Too good. I'm not experienced enough in real flying... to know what/how to ask things... sorry. Darned interesting, though. I bet you never expected your best-glide/min-sinkvideo/tests... would generate so much continued curiosity. :)
"at 3000 dead engine, there's still no hurry to get onto the ground (in a 182-like floater)" (There, I mean you still have what? About 90 seconds to make a landing game-plan? Many factors to that, and I could be WAY off).
Which airport is this plane landing at for this video?
Bourland Field. I mention it several times.
😎✈ N46173
ThanQ