Debunking Glider Spoiler Turns Causing Spin Thinking

Hi Dan

It obviously works for you but I'm interested in why you do this.

If you're doing a 180 to finals and opening the airbrakes at the start of
the turn are you not pointing away at this point with the landing area out
of sight behind you?



At 15:47 02 June 2015, Dan Marotta wrote:
That's a pretty good $0.02, Bill.


As to using dive brakes, I open them as I begin my final turn (a
descending 180 deg turn to final) and I use them during the turn as I
see fit. Once on final I use them less, maybe 1/2 to 3/4 until just
before touchdown when I open them fully. I pick my touchdown point on
downwind and fly to that point. Never do I fly to a landmark and then
make a turn to base, fly to another landmark and turn to final. That's
just asking for trouble.

My $0.02.

On Tuesday, June 2, 2015 at 11:48:56 AM UTC-5, Bill D wrote:

When watching the video I grimaced when I saw the spoilers open on downwind and base on every landing even though the glider was well below normal pattern altitude. In this situation, the spoilers should remain closed until the glider is stabilized on a short final approach.

It's fascinating reading about all the different ways people are taught to land gliders.

I was taught to check spoilers on downwind (so you can adjust if either the lock full open, or don't open at all), then about abeam the touchdown point, pull on 1/3 to 1/2 spoilers (depending on how effective they are) and fly the pattern, trying to not change spoiler setting until landing. BUT - If low, less or close, if high, more and slip. In my LS6, I set the flaps to landing (or less, if the wind is strong) on downwind and don't worry about them anymore until after touchdown.

I also like the military style "180" single turn pattern, especially if the pattern is low and tight (like say after a "low pass").

I also prefer a fast pattern, slowing down once on final - but again that is glider-specific.

And of course, ALWAYS adjust for your actual altitude/energy state and do what is needed to land safely!

Bottom line, I think it helps to get everything set on downwind (gear, flaps, initial spoiler setting, airspeed) then concentrate on flying a safe pattern. To me, messing with flaps and spoilers while making base and final turns and changing aircraft configuration throughout the pattern is asking for trouble (see all the ASW-20s that crashed early on with the gear cycling on final, ex-Libelle pilots thinking they were pulling the spoilers!)

Finally - I detest big, high, long final patterns. Why? The longer the pattern, the more chance something can get messed up. 1000' on downwind is absurd! Get in tight at 600' or so, two (or one) tight turns to final, land.

Because when you start landing out, at 1000' you should still be trying to thermal away (with a field picked out), and when you do have to set up your pattern, you will be low and close - so you can see what you are getting into!

Kirk
66

On Tuesday, June 2, 2015 at 12:00:06 PM UTC-5, Kevin Neave wrote:
Hi Dan

It obviously works for you but I'm interested in why you do this.

If you're doing a 180 to finals and opening the airbrakes at the start of
the turn are you not pointing away at this point with the landing area out
of sight behind you?

Kevin, Dan is just doing what he was taught as an Air Force pilot - single steep 180 turn from downwind to final.

In many ways the easiest way to land a plane - when combined with an overhead pattern (which doesn't really work well with gliders, unfortunately) results in the exact same pattern at every landing.

A shame civilian pilots are not exposed to it.

Works great in a Pawnee - 120mph at 500 agl on initial, pitch out just past the numbers, configure on downwind, pull off some power and a nice descending 180 turn will put you on the numbers in minimum time - and it looks good from the ground!

Kirk
66

On Tuesday, June 2, 2015 at 12:00:12 PM UTC-4, Martin Gregorie wrote:
On Tue, 02 Jun 2015 09:47:50 -0600, Dan Marotta wrote:

Never do I fly to a landmark and then make a turn to base, fly to
another landmark and turn to final. That's just asking for trouble.

Surely that can only work for a pilot who never has and never will land
anywhere but his home field.

UK training specifically warns against that trick.

My 2p.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

At our field, we teach "angles, what does it look like?", then again, most of our CFIG's are cross country/competition pilots.
Landmarks "can" work at a constant fixed location, but is no help in "Farmer Browns back 40". Heck, even an altimeter is rather useless (in an off airport landing) since you don't know field elevation.

On Tuesday, June 2, 2015 at 1:24:53 PM UTC-4, kirk.stant wrote:

Bottom line, I think it helps to get everything set on downwind (gear, flaps, initial spoiler setting, airspeed) then concentrate on flying a safe pattern. To me, messing with flaps and spoilers while making base and final turns and changing aircraft configuration throughout the pattern is asking for trouble (see all the ASW-20s that crashed early on with the gear cycling on final, ex-Libelle pilots thinking they were pulling the spoilers!)

What helps even more is starting with the POH before developing your own type specific procedures :-).

For instance: Landing flaps in the 20 are reserved for final approach, per the POH, for a whole bunch of very good reasons.

-Evan Ludeman / T8

Bruno, thanks for a thought provoking post and video.

You made me think about what I do when in the landing pattern. I fly a standard pattern, flaps in landing configuration, spoilers cracked on downwind, spoilers adjusted to achieve the right angle on down wind, base and final as required. I'm fairly certain I don't adjust the spoilers during turns.. I don't remember ever hearing anything about no spoiler adjustments during turns. However ---never really thought about it, but moving the stick, and adding rudder during the turn seems like enough workload without adjusting the spoilers too. BTW I use 1.5Vso + 1/2 gust speed. I'm going to try, at altitude (like you) turning near Vso (stall) and adjusting the spoilers to see the effect.

Chuck Zabinski

On Tue, 02 Jun 2015 10:37:23 -0700, Charlie M. (UH & 002 owner/pilot)
wrote:


At our field, we teach "angles, what does it look like?", then again,
most of our CFIG's are cross country/competition pilots.
Landmarks "can" work at a constant fixed location, but is no help in
"Farmer Browns back 40". Heck, even an altimeter is rather useless (in
an off airport landing) since you don't know field elevation.

Yes, that precisely how I was taught.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Monday, June 1, 2015 at 11:09:34 PM UTC-4, wrote:
Either a large majority of us are unaware that we are on the verge of death every time we adjust our spoilers while landing, or some people are being taught this and causing them to unnecessarily fear spoilers and using them to their full degree of helpfulness and effectiveness.

Here's a video I made trying to demonstrate what happens when you use spoilers while turning...nothing! I was a little bit of a punchy mood while taking the video - sorry for being a little bit snarky.

https://youtu.be/tC-Yqp-uHo0

Here is the description of the video:
I had been flying gliders for almost 20 years before someone on the internet wrote to me that adjusting spoilers while turning to land can kill you. What?!?! Supposedly, because your inside wing is flying so much slower than the outside in a turn, a little spoiler can spoil the whole day. I have been freely adjusting my spoilers as needed during landing my entire flying career. Why have none of the glider manuals I have ever read warned about this?

I've asked multiple CFI-G's (glider instructors) and they are also baffled this is being taught to students. I've now heard from 4-5 different people (all pilots outside of USA) that have been taught this by their instructors. Time to try to debunk this. Glider is an ASW-27B flown dry at the time of this video out of Cedar Valley, Utah.

Thanks for your insights and comments to try to help clarify the confusion.

On Tuesday, June 2, 2015 at 1:37:48 PM UTC-5, Tango Eight wrote:
On Tuesday, June 2, 2015 at 1:24:53 PM UTC-4, kirk.stant wrote:

Bottom line, I think it helps to get everything set on downwind (gear, flaps, initial spoiler setting, airspeed) then concentrate on flying a safe pattern. To me, messing with flaps and spoilers while making base and final turns and changing aircraft configuration throughout the pattern is asking for trouble (see all the ASW-20s that crashed early on with the gear cycling on final, ex-Libelle pilots thinking they were pulling the spoilers!)

What helps even more is starting with the POH before developing your own type specific procedures :-).

For instance: Landing flaps in the 20 are reserved for final approach, per the POH, for a whole bunch of very good reasons.

-Evan Ludeman / T8

Obviously, type-specific procedures specified in the POH take precedence. In the case of the LS6, it pretty much just says "for landing, put flaps in L". Having flown the 20, I totally agree with the POH procedure!

My point is that it's possible to make a landing pattern procedure so complicated that the pilot's attention is distracted "by doing everything in the right sequence at the right time" - forgetting that the most important thing is to arrive on short final at a suitable airspeed and height, and at the desired location!

Kirk
66

On Wednesday, 3 June 2015 01:37:42 UTC+2, Bruce Hoult wrote:
I think you'll find that's more like 58 knots.

In a 45 degree turn, the G loading is 41% higher, but it only takes 20% more speed to produce that G loading, not 41% more speed.

You're right.
G-loading would be 1.41G in a 45 degree bank but the stall speed would increase by 1.19 so that would make it 58 knots (107km/h).