Always trim for best glide first! No Exceptions!

A150K said:
I think 65. I know in the 172 it is 65kts.
Click to expand...

If it's 65 on the 172 then it's 60 on the 152.

I remember when I was transitioning to the 172 my CFI telling me, "check the POH always, but generally everything on the 172 is 5 knots more than on the 152."
 
tgrayson said:
Doesn't matter, glide range is weight independent.
Click to expand...

Yes and no. The best glide ratio is independent of weight, but the speed at which that glide ratio is achieved varies with weight (faster when heavier, slower when lighter). As far as achieving the best glide range, that requires a variance in speed dependant upon both the aircraft weight and the wind conditions (faster into a headwind, slower with a tailwind).

Here is a link to a page that helps explain some of that:

http://www.jdburch.com/polar.htm
 
cmill said:
It takes a private with an IR, 4 GPSs and a knee board on each leg to be god's gift to aviation.
Click to expand...

I have quickly learned that the worst situation to be in is 2 CFI's in an airplane. Too many people think they know what's going on, and it doesn't work well. Some of the dumbest things I've seen as a pilot have happened to me recently
 
I had a old timer who was my PPL instructor teach me the ABCDE checklist.

Airspeed: pitch and then trim for it.
Best place to land: pick it and head for it or circle if you have to.
Checklist: Run your engine failure checklist or trouble shoot if you don't use one.
Declare and Emergency: if you are on center, approach, tower let them know if not flip your GPS to the lat/long page and rattle your general position off on FSS or center. If no GPS let someone know what town your are near.
Evacuate: prep you passengers, shut your fuel off, ect.

At any point you are struggling to maintain best glide or are having trouble controlling the airplane focus on flying first.

This helped me in my training and many of my students as well. For some reason it is easy to remember and can be accomplished in 30 seconds or less if you are proficient in it and don't freeze.
 
A150K said:
So today I'm flying my tuna can 150 with a friend at gross weight, and I'm doing a sim engine out landing (first time in my 150 may I add, all my others were in the 172's I did my training in, in those we were usually 4-500 below MTOW). Well I start to run my mental checklist, and when I finally get around to trimming for best glide (70-75 MPH), I notice the sob is dropping like a rock. Then When I noticed double red (dead) on the VASI, I decided to let go of my ego and go around. I did a successful one after that.

Moral of the story: A PPL does NOT make you gods gift to aviation in any case whatsoever.

rant over, now for some :beer:
Click to expand...
Not trying to pick a fight, but I'm pretty sure no checklist says to trim for best glide. I think the terminology is to pitch for best glide.

In a real scenario I could care less about trimming the a/c. Besides sometimes "best glide" puts you long and requires 360's for altidude to bleed off. In such a case just nose the thing over and get it down on the ground.
 
MidlifeFlyer said:
  • best glide-establish and trim for it;
  • best place-pick it and head for it)
Click to expand...

Word. 1) Glide established, 2) Landing site selected, then the restart or securing.

A150K said:
... I was just 30 seconds behind the airplane on this run.
Click to expand...

:eek: That, IMO is a heck of a long time to be behind the airplane at any time, especially emergency landing!

cmill said:
... Full back trim will get you pretty damn close, and give you more time to look outside and fly the plane, instead of staring at the airspeed indicator.

Just be careful when you go to add full power.
Click to expand...

I can agree its important to be outside the airplane, but it really shouldn't take much time to trim for best glide (2~3 sec). Maybe it would depend on the aircraft you're flying, but I didn't think it was that close to full back. I'll have to check that out tomorrow on my next flight!
 
Chucco said:
Word. 1) Glide established, 2) Landing site selected, then the restart or securing.



:eek: That, IMO is a heck of a long time to be behind the airplane at any time, especially emergency landing!



I can agree its important to be outside the airplane, but it really shouldn't take much time to trim for best glide (2~3 sec). Maybe it would depend on the aircraft you're flying, but I didn't think it was that close to full back. I'll have to check that out tomorrow on my next flight!
Click to expand...

Works on nearly every single piston I've flown.

I'm surprised nobody has mentioned wind direction when discussing field selection. With a touchdown speed of 45 kias and a 15kt breeze this could mean the difference of a 30kt touchdown (bike crashing speed) or 60kts (car crashing speed).
 
I know about as much as my dog does about this stuff but I knew we were in for a long thread as soon as I saw "No Exceptions".


That is all.
 
With something like the performance envelope, best glide is a relative number to the situation and isn't always the book number - We all know it's related to weight.... but in all practicality, you need to know what you're looking for... if it's over water, best glide needs to be related to distance (i.e. groundspeed) - which will change based on the winds aloft.

Say you're cruising at 12,500 and the Winds aloft are a strong tailwind - you would want to pitch for min sink to take advatage of the winds for the longest period of time and TAS to give you the best groundspeed.

To exagerate the numbers to make my point... say you have a 50kt headwind, and your best glide is 50kt... what's your GS? 0 - and that does you zero amount of good... so in that situation you would need to pitch for a higher airspeed for a higher GS than the wind. This is really more for an aircraft with slower airspeeds relative to the winds aloft.

One of the best things you can do is know your winds aloft (or at least have a general idea).

This comes from an incident I had in a 172 over the ocean on a ferry flight to Puerto Rico from FL
 
cmill said:
It takes a private with an IR, 4 GPSs and a knee board on each leg to be god's gift to aviation.
Click to expand...
:yup::yup::yup::yup::yup::yup::yup::rotfl::rotfl::rotfl::rotfl::rotfl::rotfl::rotfl:
I know that guy, pretty sure I did his bfr a few years back!!!!
 
tgrayson said:
Doesn't matter, glide range is weight independent. However, 70-75 MPH sounds a bit fast; is that what's published for a C150?
Click to expand...

Glide speed, however, is, and if you use the published Vglide when you should be flying slower or faster depending on the conditions, your range will be reduced.
 
Million said:
I had a old timer who was my PPL instructor teach me the ABCDE checklist.

Airspeed: pitch and then trim for it.
Best place to land: pick it and head for it or circle if you have to.
Checklist: Run your engine failure checklist or trouble shoot if you don't use one.
Declare and Emergency: if you are on center, approach, tower let them know if not flip your GPS to the lat/long page and rattle your general position off on FSS or center. If no GPS let someone know what town your are near.
Evacuate: prep you passengers, shut your fuel off, ect.

At any point you are struggling to maintain best glide or are having trouble controlling the airplane focus on flying first.

This helped me in my training and many of my students as well. For some reason it is easy to remember and can be accomplished in 30 seconds or less if you are proficient in it and don't freeze.
Click to expand...

FTFA. Or Fly the "blanking" airplane. If you do that, you'll be fine.
 
ppragman said:
FTFA. Or Fly the "blanking" airplane. If you do that, you'll be fine.
Click to expand...

Yeah, FTFA first. I was taught the ABCD checklist, and the C and D parts shouldn't take more than 20 seconds total...well for single engine props anyways.
 
Chucco said:
Maybe it would depend on the aircraft you're flying, but I didn't think it was that close to full back. I'll have to check that out tomorrow on my next flight!
Click to expand...
I have heard it but haven't tested it myself either.

Even if true, I like the pitch for level cruise flight better. The end result in a full engine out will be the same but moving the yoke gets you to the proper pitch faster, is more like normal flight (pitch first and trim the pressure off - I like emergencies to be made as "normal" as possible) and the level pitch works just as well for partial power losses (as I found out last year).
 
You must log in or register to reply here.
Back
Top