Gust lock

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ememic99
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Re: Gust lock

Post by ememic99 »

Rich wrote: Thu Jan 06, 2022 5:04 pm How about a gust lock where the stalk goes down and pushes against the base of the rudder adjustment bracket and leaves the rudder alone. This provides something for the straps to push against without involving the pedals themselves and it preserves the notion of the stick not being held against a full aft or forward stop but in a specific position.
That’s close to what I do with factory gust lock but in windy conditions it doesn’t hold and ailerons movements simply unlocks it.
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Rich
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Re: Gust lock

Post by Rich »

Soareyes wrote: Thu Jan 06, 2022 3:32 pm
ememic99 wrote: Wed Jan 05, 2022 10:07 pm Does anyone have an idea how to lock the stick without locking the pedals? I tried just strapping it but it doesn’t seem strong.

I saw this at an airshow last year. I don't think there is enough room around the stick in a Diamond but I thought it was clever:


IMG_2762.JPG
Some variation on this would seem promising. It would fit down in the well in the seat. Some obvious tweaks:
- Make sure it's held in place in the well so it doesn't pop up with gusts. Maybe an extension upward so it's wedged against the bottom of the stick grip?
- Some kind of stalk/flag so the pilot can't get in without removing it.
A wrinkle is the danger of using it in the co-pilot seat and the pilot inadvertently leaves it in place. This is a realistic scenario. I've read accident reports where control locks are left in place due to astounding feats by pilots.
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dmloftus
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Re: Gust lock

Post by dmloftus »

For quick stops on somewhat windy days, I keep a couple of cargo bands (basically oversized rubber bands) in the back that I can quickly wrap around the seat and the stick. Takes about 10 seconds to install and holds ailerons and elevator stable. When I'm trying down outside my hangar, I usually use the factory gust lock on the copilot side. I usually leave the copilot pedals fully back to avoid continually running the pedals back and forth.

https://www.amazon.com/US-Cargo-Control ... s9dHJ1ZQ==
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Rich
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Re: Gust lock

Post by Rich »

The needs of the DA40s and DA20s are obviously different with respect to locking the rudder.
- Free-castering nose wheel: good :thumbsup:
- Coupled nose wheel: bad :thumbsd:

There is a weakness in what Diamond supplies for each. For the 40 (and presumably 20), the control lock is designed to work with the rudders pedals pulled to the rear. Most of us fly with the pedals well forward. An illustration was posted very early in this thread about modifying the lock to work with the pedals full forward (or nearly so). Leaving the co-pilot pedals fully back has never been a workable solution for me. This picture shows my modification alongside the one originally supplied. I ordered a second one years ago and modified it as shown. (Naturally I retain both - did I mention I have 10 headsets :D ). Note that Diamond made changes at each end of the device between the two versions.
Control Locks.jpg
Whenever leaving the airplane outside no matter how short the stay, even in calm winds, I always lock the controls. Why? Propwash from taxiing aircraft and, especially, helicopters :scream: .

I had an idea to suggest regarding the retracts, but it wouldn't have worked for the electrically adjustable implementations. It also appear to me the way the straps are installed on the retract locks have an innate weakness. In the photos above note that each side's strap is independently rigidly attached to the device. That means that lateral movement is not possible without some sort of strap failure. From what I can glean it doesn't seem to be that way for the straps of the DA42 control lock. Pictures would help.
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slowbird
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Re: Gust lock

Post by slowbird »

On collecting a DA42 at the factory in Austria a few years ago, a very helpful Diamond instructor used the seatbelt to lock the controls, and pointed out that aircraft with the yaw damper and the nosewheel steering don’t need the rudder lock anyway. On windy days at the base of the Austrian Alps, that rudder is not moving, and the aircraft can still be towed.

All I do on both the 42 and 62 is pull the stick full aft and place the seatbelt over the base of the handle and pull tightly. Nothing moves with that. The ailerons won’t budge and the rudder is fine, plus the aircraft can be towed in and out of the hangar easily. Give it a try, and see what you think.
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Re: Gust lock

Post by Colin »

But then if there's a stiff breeze the plane wants to go nose-up, correct?
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Re: Gust lock

Post by Boatguy »

snow-on-cessna.jpeg
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Colin
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Re: Gust lock

Post by Colin »

That looks like it's going fast even standing still. I'm convinced that's the proper gust lock position.
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Re: Gust lock

Post by slowbird »

Colin wrote: Wed Jan 26, 2022 1:31 am But then if there's a stiff breeze the plane wants to go nose-up, correct?
Logically yes, but I wouldn't be sure the force is enough and I took the view if its good enough for the folks in the Austrian Alps, its probably ok. Aircraft is always hangared, but I have had it parked outside in 60-70kts and not encountered any issues, any stronger than that and I'd want the aircraft in the hangar anyway.

Plus, with 40kgs of TKS fluid in the nose, another 20kgs of excess weight in the nose baggage and full tanks of fuel - what wind strength would be required to lift the nose from the tailplane force alone?

I'm more concerned about the ailerons flapping about in a wind and the elevator going back forth with wind while the aircraft is parked on the ramp for a couple of hours - and in those conditions the seatbelt method works a trick.

I shall report back if I ever find the aircraft nose up :lol:
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Re: Gust lock

Post by photoSteveZ »

Colin wrote: Wed Jan 26, 2022 1:31 am But then if there's a stiff breeze the plane wants to go nose-up, correct?
You're right, Colin: the optimum positioning for a control lock is to hold the stick forward of neutral, i.e., somewhat nose down. That way, a stiff headwind while tied down tends to keep the wing's angle of attack low; with a taildragger, it will actually lift the tail off the ground, unloading the wing...which is a Good Thing (see below); and a stiff tailwind while tied down will tend to keep the tail low (also a Good Thing). A stiff crosswind may put a lot of strain on everything, but that can't be helped.

I live in a place famous for strong, west, downslope winds: the Front Range of Colorado. For many years I flew gliders and taildraggers out of Boulder (KBDU). You could say, why don't you tie the airplane down with the nose pointed into the prevailing wind? Well, when the wave is working and the rotor is directly overhead, I've seen the wind switch from 60+ knots out of the west to 60+ knots out of the east (and back again) in a matter of seconds.

We got pretty good at tying things down, but there was one time when the winds were so squirrely that a Super Cub towplane tied down (facing south) between two gliders (facing west) ended up in a heap across the road to the north. The tiedowns didn't fail, the airframe did: the Cub's wing struts were still attached to the ropes, which were still tied to the ground, intact. And the gliders on either side were untouched.
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