Jump to content

Recommended Posts

I've started thinking about my planned 1/48 "Special Duties" Lysander, and I ran across something in Hugh Verity's We Landed By Moonlight which has puzzled me. I'm aiming to model an aircraft as it would have appeared on the ground in France during a pick-up, and had assumed that this would involve wing slats extended and flaps lowered. But in Peter Proctor's appendix on "Modifications to the Lysander" he says, "I also remember the pilots telling the passengers to push back the automatic flaps as they left the aircraft."

I think this means that the passengers in the rear compartment lifted the flaps into the horizontal position (thereby also retracting the inner slats) once they had the rear canopy open. I've certainly seen photographs of parked aircraft with the flaps raised, so presumably this was possible to do, despite the entirely automatic operation in flight--I just can't puzzle out why they would do this, minutes before a short-field take-off.

Link to post
Share on other sites

It would be (generally) unusual to take off with full flaps, this actually reduces acceleration a d climb performance.

 

Similarly, taking off with no flaps at all actually gives an overall better performance, albeit a longer take off run.

 

I know the lysander flaps were automatic but I don't know if the flaps had multiple stages.

 

It is possible they pushed the flaps back to half flap, which would give improved short field performance without affecting climb performance too much.

  • Like 1
  • Thanks 1
Link to post
Share on other sites
57 minutes ago, wellsprop said:

It would be (generally) unusual to take off with full flaps, this actually reduces acceleration a d climb performance.

 

Similarly, taking off with no flaps at all actually gives an overall better performance, albeit a longer take off run.

 

I know the lysander flaps were automatic but I don't know if the flaps had multiple stages.

 

It is possible they pushed the flaps back to half flap, which would give improved short field performance without affecting climb performance too much.

Thanks for this. The Pilot's Notes for the aircraft seem to imply that slats and flaps deployed smoothly, rather than in stages, driven by air flow. The Haynes manual says that the pilot could lock the flaps (though I can't seem to find the relevant control in the Pilot's Notes cockpit diagrams). This explains the photographs of parked aircraft with inboard slats stowed and flaps raised. But asking the passengers to find an appropriate flap position for take-off, in a rush, in the dark, seems fairly fraught. But likewise, locking the flaps fully raised (an easy position for the passengers to find), then unlocking them at some point during take-off when speed was sufficient to stop them fully deploying, also seems like a way to complicate life.

Link to post
Share on other sites


It does seem counter-intuitive (and almost suicidal), to trust any passengers to put the flaps up prior to performing a rough field take off at night. Not what I’d call good drills - unless agents were thoroughly instructed in aircraft ground handling procedures as part of their training.

 

Could it be that the Lysander’s flaps obstruct some kind of entry/exit from the rear cockpit when they are down? If so, could it be that the pilot was simply reassuring passengers that it was okay for them to push the flaps out of the way prior to exiting (you know how some passengers can be terrified of touching bits)?

 

  • Like 1
Link to post
Share on other sites

On the flap/slat system in general, this thread is worth a careful look:

https://www.key.aero/forum/historic-aviation/91151-westland-lysander-auto-slats-flaps

 

And what I think is a "follow-up" from Andy Sephton to the article linked to in the above thread.

Edited by gingerbob
  • Like 1
  • Thanks 1
Link to post
Share on other sites
6 hours ago, Blimpyboy said:


It does seem counter-intuitive (and almost suicidal), to trust any passengers to put the flaps up prior to performing a rough field take off at night. Not what I’d call good drills - unless agents were thoroughly instructed in aircraft ground handling procedures as part of their training.

 

Could it be that the Lysander’s flaps obstruct some kind of entry/exit from the rear cockpit when they are down? If so, could it be that the pilot was simply reassuring passengers that it was okay for them to push the flaps out of the way prior to exiting (you know how some passengers can be terrified of touching bits)?

 

The agents who were being ferried out certainly got a fair amount of training, including practice at exiting the aircraft--there was a well-established drill to get people in and out in the shortest possible time. So it would seem possible that they also practised whatever it was they were supposed to do with the flaps.

The flaps were certainly easily accessible from the rear compartment, but do look like they'd be more of an exit hazard in the "up" position rather than "down". Here's an illustrative photograph from the Haynes manual:

lysander-rear-compartment.jpg

That does look as if the corner of a raised flap would catch you right in the back of the head as you tried to get on to the exit ladder (out of sight in this image, on the opposite side of the aircraft).

  • Like 1
Link to post
Share on other sites
6 hours ago, gingerbob said:

On the flap/slat system in general, this thread is worth a careful look:

https://www.key.aero/forum/historic-aviation/91151-westland-lysander-auto-slats-flaps

 

And what I think is a "follow-up" from Andy Sephton to the article linked to in the above thread.

Very useful, thanks. It's interesting that the flap lock (with options for up and 3/4 down) is described as having been removed in later aircraft. This is borne out, to some extent, by the labelled photo of the port side of the Lysander III cockpit in the Pilot's Notes, which shows the curved slot for the flap lock (just behind the throttle), but doesn't attach a label to it, and doesn't seem to show any kind of control knob. But if there was no flap lock in the French SD Lysanders, what would be the point of the passengers fiddling with the flaps?

The flap lock slot is also visible in photographs of the Shuttleworth Lysander, and seems to be unoccupied by any sort of control knob. So I guess that means the take-off run is actually started with full flaps, which retract as speed increases.

Link to post
Share on other sites

If you want a good overview of what it is like to actually fly the Lysander, Dave Hadfield who flies the Vintage Wings of Canada Lysander, has a video up on youtube, which in part covers the operation of the slats and flaps and also the trimming of the tail for take off and landing.  A great perspective from the pilot's point of view.

 

 

  • Like 7
Link to post
Share on other sites
On 10/19/2020 at 3:04 AM, Hamiltonian said:

That does look as if the corner of a raised flap would catch you right in the back of the head as you tried to get on to the exit ladder


Doesn’t it just!

Something to be wary of when attempting a fast exit before Jerry arrives on the scene!

  • Like 1
Link to post
Share on other sites

Thanks all. I feel I can make a very marginal case for flaps up and inboard slats retracted, but I'm leaning toward slats out and flaps down.

The deciding factor will really be how well I can manage to make a set of inboard slats (I have the outboard slats and the flaps from CMK). A bit of experimentation required before I start sawing, I think!

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...