What the Heck is Best Glide Anyway

[@myrlstone8904]

After getting my private ticket and moving on to the full deck of advanced tickets and ratings, I spent some time in sailplanes. It’s surprising how quickly one adapts to the planning required to execute a spot landing with no power available for a second try. It’s a good skill to have in one’s back pocket and I would recommend it to any aspiring pilot. This was many years ago and done through a glider club: the cost was very reasonable. Free in fact, as they were looking for a tow pilot which resulted in many hours and landings in a tail dragger. Ask around, though fair warning - towing is not fun.

[@derrickmcmaster5309]

I like the analogy to look out the window to the wingtip to the ground and that is where you can make it to land. I always learn something from your perspectives on flight. Thank you.

[@fatherdaughterflights346]

“Try it out first… before you need it for real.” Literally words to live by. Thanks Scott

[@FPVREVIEWS]

It’s also helpful to add a little speed when going into the wind for penetration and lower a little for a tailwind when trying for best glide. More of a factor for lighter slower airplanes. Great discussion 👍🏼

[@philipcobbin3172]

I learned first on a Glider years ago at Purdue and was taught a simple rule....look out the window at whatever speed you think will work and answer the following question: Is the target point rising or descending on the wind screen. If it's rising you're likely screwed. Had it happen in a glider once from from mousing up a pattern near some big sink and there's another way to look at the energy problem. Trade potential energy for kinetic energy. Counter intuitive....dive...in my case I went into ground effect over corn looking at the APT on my left for sufficient penetration down the runway. Pull stick back to convert the speed to altitude (to do base/final turn in one act) to clear power line and voila!..wings level and on the runway. Power pilots really need to understand their aircraft's dead stick performance characteristics. But the sight view method I described applies literally on the fly. That stick forward and accelerate maneuver is very very counter intuative. May not work so well on hershey bar wings.

[@FlyWirescottperdue]

Phillip, thanks for watching and sharing. Your drag polar in a glider is much different than the thicker chord wings in power airplanes and plays a larger effect. Potential to kinetic trades are not as effective.

[@christophvz]

Thank you for another thoughtful and informative video Scott! These are excellent points and I fully agree with what you said. Your previous video inspired me to practice emergency landings in the real airplane (C182) and spend several hours in my BATD (Redbird TD2). One thing I’ve realized is that I’ve always taught my students just the abridged version - i.e. follow the ABC - Airspeed, Best Place to Land, Checklist. But now I’m realizing that there are more practical considerations that ought to be thought through carefully and practiced extensively. Below are some key points that I’m writing down in my CFI notes. Curious about feedback from other fellow pilots and instructors here. Emergency landing - key points 1. Pitch for Vdmms (defined minimum maneuvering speed, 1.404 x Vs, 72 kts in Cessna T182T), trim to reduce control pressure, and fly at that speed all the way to the ground; do not go above it and do not go below it until flare. Going above it will increase your kinetic energy which will be difficult to manage. Going below it will bring you closer to a stall and loss of control. Just fly Vdmms all the way to the ground. 2. Aim for the best available landing spot, ideally an open field, a runway, a road, a beach, dense trees, or water, in that order. Prioritize not hurting anyone on the ground before saving yourself. Runway is your second best option (unless you are in a tight traffic pattern already or in a high overhead position) because it will make it difficult to consider other options. I call it runway(titis). Aim for either straight in or low key position, or downwind high key position to your intended landing spot. 3. Continuously reevaluate if you can make your intended landing spot and choose the second best option if you know it’s not going to work out; judge if you can make it using your sight picture (i.e. angular distance); do not attempt to stretch the glide. If it’s not working out, accept your situation and remind yourself that your biggest risk is losing control of the airplane. So don’t. 4. Do not make turns below 500 feet; the loss in lift will induce an urge to pull back which will be extremely difficult to resist. Better to crash wings level into a suboptimal space than lose control close to the ground. You only need 30 ft of distance to stop and survive the 9G crash (see FAA flying handbook Chapter 17: Emergency Procedures). 5. Do not put full flaps until landing is 100% assured and you’re ready to flare. Unlatch the doors before touch down. Aim to be slightly high realizing that winds can shift close to the ground. Give yourself good safety buffer (i.e. avoid aiming for the edge of the field for example). 6. Evacuate promptly; do not just sit in the airplane thinking that the worst is behind you. It ain’t over till it’s over.

[@FlyWirescottperdue]

All good observations. Thanks for sharing!

[@packardexelence]

LOVE EM ALL;BUT #6 MY FAVORATE!!! AIRPLANES HAVE LIVE WIRES & LEFT-OVER FUEL!!!; I WAS A FUEL SPECIALIST IN THE U.S.A.F. ONCE PUT- OUT SMOLDERING WIRES ON A FUEL TRUCK CAB SEPERATEING THEM USING HANKERCHIEF TO PROTECT FINGERS!!!--CALLED IT IN; BUT WAS DONE BEFORE ANYONE ARRIVED!!!!--8 FEET AWAY FROM 5,000 GALLONS JP-4!!

[@malcolmovenden8557]

Any glider pilot knows this information intimately. His life may depend on it. Min sink speed is used for circling in a thermal to maximize rate of climb. Best glide speed is used to get between thermals with minimum altitude loss. High performance sailplanes are loaded with water ballast to increase the speed at which the best glide angle of attack is achieved (without any decrease in glide ratio) and hence enable faster times around a course in a speed competition. Of course, the added weight of the water ballast also increases stall speed so a sailplane will dump the water prior to landing. You gave an excellent explanation for those who have not been trained as glider pilots.

[@FlyWirescottperdue]

Thank you Malcolm! I aspire to be a glider pilot!

[@vernmeyerotto255]

Very good video, and we both agree on how to deal with an engine out. First, fly the plane, second find a suitable field. Any time or altitude spent on anything else until you have a plan is a waste. Exactly what I was taught by my flight instructors.

[@alasdaircrawford2695]

Good discussion… FWIW worth mentioning that gliding downwind rather than into a headwind will increase your range (achieved glide ratio) a bit too.

[@ivansemanco6976]

Other thing is, best glide ratio speed is different for downwind and headwind. For downwind glide ratio will increase but speed is little bit lower than in the book, in headwind case glide ratio goes down but we need to increase the speed little bit to get maximum available. But this is academic discussion, for glider you have proper data to calculate best glide speed with wind correction, which isnt case for most of airplanes.

[@SVSky]

Yeah and it depends on how strong the wind is, sometimes, if the wind is strong enough it's worth going to min sink and let the wind carry you downwind.

[@txkflier]

Dan and Juan say to put a line on your ASI at 1.41x the clean stall speed. They call it “DMMS”. On the Cherokee Arrow that I used to fly, it’s within a few percent of the best glide speed. Sounds pretty simple to me. I think those that stalled and spun in thought that slower is better. I would at least stay above 1.3x Vs until I’m lined up on where I’m landing.

[@picogang]

Yes good point. I am not sure how to calculate min sink but as it’s somewhat lower than best glide it will probably be a speed at which it is not safe to manoeuvre and therefore min sink is not a useful speed when manoeuvring to land ?

[@ivansemanco6976]

@@picogang Min sink is good to know for gliders to get climbing in thermals and for us its minimum vertical speed for hiting ground if we use constant angle aproach without flare(Im kidding of course). As you wrote, this speed is low and dangerous for manoeuvering to land, small mistake and you are part of statictics. Best glide is mostly very close to Vy, but in the POM both speeds are available. For 4seater Im flying, I have graph where best glide speed is drawn as function of weight, same as aproach speed and Vy and Vx.

[@txkflier]

Another thing you probably should do is mentally divide the field into three equal lengths and aim for the end of the first third. Once you know you have the field made, lower the flaps or slip it to land a little before that point.

[@megadavis5377]

That's interesting, your mention of an AOA indicator. I have been flying the same type airplanes (Merlins and Metros) on and off again since 1983, and I can honestly say that I have never so much as glanced at the things other than occasionally in cruise flight or when I'm bored while waiting to copy a clearance... At the locations I would need an AOA indicator - takeoff, approach and landing - I am too busy to even remember that they are there. And they sit right in front of me. However, in the case of the loss of both engines, I can certainly understand the urgency of "white-eyeing" the thing all the way to the ground.

[@christoerasmus8068]

Thanks a lot Scott! One of the most valuable lessons I was taught relating to being ready for an engine failure, was exactly this: No matter what the altitude you are at, the field you need to select will not be further than your wingtip, no matter what you fly. I've practiced this in Bonanzas, Cessnas, Jabirus etc. Sure there are many variations with regards to speeds, approach angles etc but I think your advice on 'through the wingtip' is solid! Love your work!!

[@914va]

I have landed a high wing and a low wing with engine out...(emergency landings) ...I picked out my field..set MIn. sink and had two very successful landings. FLY IT!!

[@FlyWirescottperdue]

Thanks for sharing!

[@robertmailer4978]

Scott, The eye through the end of wing work really well, in my aircraft minimum manoeuvre speed is the same as best glide, and approach speed, love the channel

[@tomblack9401]

Good video, Scott. I didn't have any trouble with the first video because I understand the GFC500/600 ESP. Also, I teach this stuff in some of my Aerospace Engineering classes. I do have an Alpha Systems AoA system in my A36 and love it, but I did the calibrations on it and I understand how it works and - more importantly - its limitations. It is more like measuring a length with a ruler which is marked only in 1-inch increments: it is ACCURATE but does not have the RESOLUTION for the precise airspeed management needed for something like a short-field landing. Like Tom Turner, I use it for getting on the rough condition quickly then cross check and fine adjust as needed using airspeed.

[@willhibbardii2450]

My rule of thumb is the best place to land a single engine piston aircraft in an emergency catastrophic engine failure scenario is generally underneath and strait ahead especially on takeoff. You are already heading into the wind and tracking the lowest ground speed. Learning how to perform short field landings builds confidence that you don't need a big field to land a light aircraft. The plan to glide to the big field most times isn't the best option. Proficiency to land on a dime with almost no roll is a skill set of experience and practice. I was initiated to this by the instructors that crop-dusted in the old Agg Cats. Your milage may vary finding such guys today.

[@MrCobb-rq8iv]

To clone the hearing aid sales pitch, "I heard you the first time". I'm not there yet, but Min-sink makes sense to me and give me the longest miles to the ground. I like the looking over left wing. Kinda back to flying by the seat of your pants, isn't it? Thanks, I'm eager to keep learning.

[@FlyWirescottperdue]

Mr Cobb, I think the ability to keep learning makes us better pilots! Just a reminder- Min-sink is time, Best Glide is distance.

[@MrCobb-rq8iv]

@@FlyWirescottperdue Without the actual experiene my first guess is distance is the best. Regards.

[@farmerbobross]

Maybe you could comment on the advice in "Stick and Rudder" about the imaginary cone underneath the aircraft that gives you an area where you can get to in a forced landing situation. Once you figure out the angle it's always the same. The area of useful landing area on the ground gets bigger with altitude. That has served me well for years. It might help others too. Great work as always! Thanks.

[@FlyWirescottperdue]

That is exactly what I suggest in this video.

[@alscustomerservice187]

Thanks! great discussion.

[@dallasC822]

As a student pilot I had a misconception that I hold the best glide all the way to touch down. You hit it on the head that once you are committed to the landing site, you need to transition to manipulating your speed/sink to hit your landing point at the slowest ground speed you can manage. The FAA has a great illustration on page 3 chapter 17 of the Airplane Flying Handbook of the difference distance between 50 mph and 100 mph ground speed deceleration at 9G's. Thanks for the video!

[@mytech6779]

Thats basically a typical short field landing, come in at a preferred approach speed (in this case best glide) then slow down for the round out or to avoid overshooting the aim point. I don't know why a pilot would think they need to plow into the ground at full approach speed just because they have cut the power; other than being locked up in a blind panic, but not much can be done at that point any which way you try to slice it.

[@Joe_Not_A_Fed]

I kinda just ignored the autopilot stuff from the 1st because I figured you knew what you were doing...which was not using autopilot since that would negate the entire experiment. What I got from the previous vid is that it was a graphic representation of how different single engine prop planes react to similar inputs. I have never tried it but perhaps best glide can be achieved in a 172 by full up trim. Obviously, a Bonanza is a different cat. For me, the lesson is that you better read up on the plane you are flying today because whatever you flew yesterday, might not be all that relevant. Best takaway...you don't have as much time as you think if it gets really quiet in the cockpit.

[@FlyWirescottperdue]

Joe, by george, I think you've got it!

[@richardfischer9811]

The whole subject of engine failure emergencies is a complex subject that could use a lot more verbal and in-flight training. First off, there's drilling the thought sequence into the student's head. I always taught that it's an alphabetical checklist that needs to become automatic. "A" is for AIRSPEED. That's what needs to come mind as the highest priority. Don't stall and spin ! "B" is for BEST PLACE TO LAND. Second on your checklist. Turn toward that place. "C" is for CAUSE. Make a quick check of fuel, incorrect switch or handle positions. Especially items that you recently moved. "D" is for DECLARE. Make a Maday call if you can do it quickly. That's fourth down the line because A, B, and C are life saving actions and have higher priority. You only need to make a Mayday if you don't kill yourself by neglecting the first three.

[@nickxidis9571]

Great follow up. I felt the use of the auto pilot in the previous video distracted from the point you were trying to make, this one cleared it up. Also, liked your advice on flying the plane in the actual emergency, there’s enough stress without straining at nats. If you don’t stall/spin your very likely to survive an off airport landing.

[@Saltlick11]

Very helpful. Been practicing a lot of engine out's (heavy HP single) and two things are noteworthy and unexpected: 1) Airplane descends much more quickly than anticipated 2) In Base and Final turns, 1500FPM is a major altitude loss component of the process.

[@emergencylowmaneuvering7350]

Those speeds are supposed to be marked on AS indicator. I used to have them marked on my Cherokee i taught from in the 1990's. Blue line on full gross Vglide speed. I put other markers too.

[@gregedwards5608]

I'm a glider pilot, we live by the distinction of the 2!.

[@dermick]

To drill the right number in my head, I trim for Vbg on most of my flights when I get near the airport. Then I look at the glide ring on my EFB and see if it stays consistent with reality. I have some very conservative numbers in the EFB. Sure hope I never need to use that info in a real situation. Key thing if you have an engine failure is to fly it all the way to the crash site. Gear up in a field if you are RG. Roads mean wires, cars, bicycles, trees, fenceposts, people - go for a field. Find some corn. Be safe!

[@FlyWirescottperdue]

Bravo, Dermick!

[@JWH-01]

Great video! Thank you for the lesson. Connecting the math to the real world sight picture looking down the wing is key. There won't be time to crunch the numbers in the heat of the moment if the situation occurs in the real world.

[@richardfischer9811]

When your engine quits or for some other reason you need to get it on the ground ASAP, remember that plane is no longer your best buddy. It has let you down and put your life in danger. The only thing you want out of the plane now is to get you down one last time and then the insurance company can have it. If you are flying day VFR, you should try to have a succession landing spots in mind as the earth rolls along beneath you. Always keep the next good spot in mind as you pass by. That will give you more time to consider the merits of each spot before it all gets quiet. Gives you time to consider wind direction, terrain, landing surface, distance to emergency assistance. Always nice to land near a house so you don't have to walk so far for help. Try not to go for a landing spot that tests the gliding performance of your plane. Pick a spot that you know you can make and if your airspeed has to be a little on the high side, so what ? You can slow up as you approach touchdown.

[@SW-be8zm]

Thanks for the fact based common sense approach towards getting us on the ground safely in engine out situation.

[@dcannon1]

Plug for glider rating. Better yet primary training in glider.

[@billcraig]

Absolutely GREAT video, Scott!

[@nightcrawleroriginal]

Opened up a can of worms with this topic, I did think you had the Auto-Pilot engaged because you mentioned it in the video, the machines I flew didn't have it (helicopters) so I have no idea what sound I was suppose to hear that disengaged it. Personally, I use the KISS method, it makes life a whole lot simpler that way. Thanks for the update. :)

[@SkylineBaronPilot]

Great video Scott! This was awesome. Thank you.

[@user-iw3mr2lv6f]

Scott What is the min sink for your F33 and old A36. Another great video! Looking forward to the video on the Garmin autopilot. Thanks for what you do.❤

[@FlyWirescottperdue]

76 kts in the A36. About 68 in the F33C

[@user-iw3mr2lv6f]

@@FlyWirescottperdue Thanks Scott. Question I Use 80 knots crossing runway in A 36 (1988) what did you use in yours? As always thanks for what you do.

[@txkflier]

@@FlyWirescottperdue But when you’re going that slow, how much banking and turning can you do without stalling?

[@davidwhite8633]

@@txkflier Probably more than you think ( as long as you keep the ball in the center ! ). The lower the A/S the lower the turn radius so fine tuning the turns closer to the ground is easier.

[@Vmaxfodder]

You're awesome Scott!

[@wicked1172]

Great discussion !

[@josephsener420]

Hey, I really enjoyed the first video. Best glide in a Dakota is 85 kts! That’s where I am going.

[@iflycentral]

For reference; I tested the full up trim technique in my Sundowner a couple years ago, and got the same results. Airspeed well below best glide. Dangerously slow in fact.

[@davidwhite8633]

It’s good for an IA (immediate action). You get roughly minimum descent speed which means staying as high as possible as long as possible. Time to tell ATC where you are . Then , adopt Vbg and look for a field .

[@iflycentral]

@@davidwhite8633 No. Not in a Sundowner. It will take you right into a stall. Best to just put in enough trim to get roughly to best glide. Arbitrarily going full up in a Sundowner will more than likely get you killed. Might work fine in some planes like 150s, but that was Scott's point. You need to know how the type you are flying is going to react.

[@davidwhite8633]

Perhaps I worded it incorrectly. The trim wheel deal obviously would be different in different aircraft , but I was commenting on your last two sentences. Vmd ,speed of minimum descent, can be useful when a field is well within range and diagnosis of a problem is more important . Some pilots use it all the way down , but it depends on initial altitude and layout of available landing spots.

[@glennwatson]

There's a story we have in Australia in training. You are flying in the outback over land with lots of crocodiles with a copilot. Your engine fails. You see a nice landing spot without the crocodiles underneath. You decide to open the door and throw your copilot out so you can reach the land. Unfortunately both yourself and your copilot are now crocodile food.

[@peterbrown6224]

Drop bears will get you if the crocodiles don't.

[@Dilley_G45]

???

[@glennwatson]

@@Dilley_G45 changing your weight doesn't affect your glide distance. Just potentially your best glide speed. So it's a story that sacrificing your copilot won't help you glide further. Handy during your ground theory exams since the question has come up a couple times for me.

[@Dilley_G45]

@@glennwatson ah I see.. But you live a bit longer 😆

[@kurtak9452]

Great lesson.

[@nancychace8619]

Thanks for sharing. Interesting about the auropilot. I've noticed people tend to assume a lot these days. Is it b/c of a lack of attention span? The math is interesting. I'd need a little more input on that one. I liked your final conclussion, though - just fly the airplane. Hope things go well.

[@FlyWirescottperdue]

There is a LOT of rounding up.

[@skydive1424]

This is basic glider pilots knowledge. I’m surprised how few power pilots know this. Head and tail wind affects your best glide speed which may deviate from the best L/D. May not be a whole lot different for GA a/c but for high performance glides it makes a big difference

[@mamulcahy]

Do I detect some emphasis in your delivery?

[@Iflyagrasshopper]

Hmmm I fly a biplane… what is glide ratio? 🤔😂 humor aside I glance at the asi and then set an angle and try to maintain the angle until I have my landing spot in reach.

[@bernardc2553]

Measure with a Micrometer, then make the Cut with an Axe, LOL

[@marc-andremuller1954]

I think your aircraft has CAR 3 or FAR 23 at a very early amendment level as a certification basis. 23.2140 came into effect only a few years ago and wouldn’t be retroactively applicable to your aircraft. Your reference would be 23.161 or the corresponding CAR 3 standard. This doesn’t take anything away from your argument though. (actually per tcds 3A15 the certification basis is Part 3 of the Civil Air Regulations as amended to May 15, 1956, and Amendment 3-8. the trim standard is CAR 3.112 and requires a specific envelop within which the aircraft can be trimmed; it would be pure coincidence if the best glide speed would happen to fall on the exact limit of trim travel.)

[@FlyWirescottperdue]

23.161 specifies a zone the bottom of which is .9Vh or 1.4 Vs1. The original Bonanza was certified under Car 3…. But they are ALL about force in the zone. Nothing about a specific speed. A coincidence indeed, but Best Glide would be well within the zone. Thanks for commenting.

[@azcharlie2009]

Question: If you trim to full up with no power, and then suddenly applied power, or the engine came to life, wouldn't the airplane pitch up further and cause a stall? I know you can apply nose down pressure and override that pitch up attitude, but what if it was too late to do so?

[@FlyWirescottperdue]

Yes. That is known as a Trim Stall.

[@robstanton9215]

I’m with you. Shoot for the closest suitable spot and FLY THE DANG THING ALL THE WAY UNTIL SHE STOPS!!

[@JSFGuy]

Aight... Got a notice from screw tube this time. Clear prop.

[@michaelwilliamsd.o.5006]

Good discussion

[@MalcolmRuthven]

As I said as a comment to your prior posting on this, how hard is it to remember the indicated airspeed for best glide? Answer: Not hard at all, and it's simply something every pilot should know about the plane they're flying, period.

[@FlyWirescottperdue]

Agreed!

[@ph5915]

I wonder why you don't install an AoA system on your plane?

[@FlyWirescottperdue]

Good question. Do you remember me saying in the video that AOA for light GA is pressure differential? That is an approximation of AOA and not accurate at high AOA. You need a vane AOA sensor and they are in compatible with single engine airplanes.

[@ph5915]

@@FlyWirescottperdue Ah, yes, I recall you saying that. I understood that for light planes like my old 172 they really don't add much value, the airspeed is a close approximation, I just thought the Bonanza class it would have more value, but it seems they don't. Thank you, Scott!

[@tomblack9401]

@@ph5915 I do have an AoA system on my A36 - Alpha Systems. As Scott says, it is pressure differential. It is accurate, but does not have the resolution of a military-grade system. I use it to "rough in" the AoA for landing then fine tune it with the airspeed. Even the rough in is good enough for normal operations, but if I want short field performance I need to be spot on. The AoA is a good system and I like it, but you have to know its limitations.

[@ph5915]

@@tomblack9401 Thank you Tom! Love yo hear new information, which I often do on this channel!

[@ericsd55]

Excellent! I was screaming at the screen reading the comments in the other video. Drove me nuts. :) I hope this clears things up for everyone.

[@txkflier]

Prior Proper Planning Prevents Poor Performance. Mark your ASI or add a placard, practice emergency landings, and be thinking about what you’d do if the fan quits.

[@iheart545x39]

FedEx md11 uses aoa for landing speeds. Far superior

[@Andre.D550]

😎

[@johnfitzpatrick2469]

"My nickel on the grass" What's wrong with a glide speed ratio checklist for your plane? Engine out altitude+airspeed ∆ = time to LZ (flat and long) optimal solution. 🛬