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-   -   tiedowns (https://www.pprune.org/private-flying/560193-tiedowns.html)

flyingscotsman99 20th Apr 2015 19:12

tiedowns
 
The latest advice I hear for overnight parking in strong wind is 'tail into wind'.
OK, so the plane is tied down at 3 points; then, I am told, the stick is fixed forward, ie down elevator. But I feel uncomfortable with this; it means a lot of force on the elevator towards the hinges. Not sure about the ailerons, or flaperons in my case, either.
I am talking about a Light sport aircraft in, say, up to 30 kts of wind. Can anyone offer an authoritative view on this?

Mach Jump 20th Apr 2015 22:14

Conventional wisdom usually says that taildraggers should be tied down tail into wind and ailerons/rudder locked neutral, elevator locked in the 'down' position. Nosewheelers tied down facing the wind with all the controls locked neutral, or elevator 'down'.

The above is ideal, If you know what the wind direction is going to be. The fact is that it's more important to make sure that the tie downs are secure, sufficient in number, (wings and tail for a taildragger/wings, tail and nosewheel for a nosewheeler) and strong enough to withstand a force at least equal to the weight of the aircraft.

External control locks are better than internal ones.


MJ:ok:

piperboy84 21st Apr 2015 06:31

I use this device, has worked pretty well

The Claw - C-100 Aircraft Anchoring System - The Advanced Aircraft Anchoring System - The Claw Tiedowns

flyingscotsman99 22nd Apr 2015 15:39

tying down
 
Thanks for the responses. Yes, I have used the Claw and it could probably hold down a Sherman Tank. Bit chunky for a Eurofox at 10 lbs, so I am making a simplified version based on Camping nails and aluminium tube. I have an external elevator clamp which would hold it neutral, but I am not clear how an external device would hold an elevator in the Down position. Fortunately the Fox lends itself to having the stick held forward, and I do not plan to be out in more than a strong breeze, so I think I am happy now. Thanks again.

9 lives 23rd Apr 2015 00:33

I am opposed to internal control locks in all but the most dire circumstances. They will allow flight controls to be forced through the enitre control mechanism against the cockpit control lock. It is a certainty that fatal loss of control accidents have occured because of hidden control system damage from cockpit control lock use. THIS is the serious safety of flight risk the pilot CANNOT detect during a walk around. Danger danger! I have found myself airborne in a 182 with hidden aileron damage, which was not detectable during the walk around.

in an older Cessna POH, Cessna recommends that each tiedown point be able to withstand a 700 pound pull. This kinda makes sense, in that your average GA plane is 1200 to 1800 pounds empty, and like to fly at 40MPH, so at that 40MPH wind will create around 700 pounds lift per wing. Story:

back in the day, I was the custodian of a 172, which shared the apron with a Seabee. Each were tied to a few hundred pounds of concrete slabs. A paniced phone call from the non pilot farmer very early one morning; the two planes had been blown into each other over night. I was respnsible for the 172. I rushed to the airfield. The 172 was exactly as I had left it. The Seabee (a rather heavy, unaerodynamic plane, had bumbled it's way a few hundred feet across the apron. It was at rest with it's wing shadowing the 172's, but having not contacted, and those concrete slabs on the rope were now swinging off the ground, suspended by the tiedown rope, still tied to the Seabee wing, but now passing over the aileron of the 172. I bent back out that curled train aileron edge. I moved the 172 away, for it's safety, the Seabee was badly damaged. i learned about tying down from that.

I have seen planes lying on their backs, with ropes and anchors still attached.

There is something to parking taildraggers tail down into the wind, but I would rather tie them down really well, into the wind. If I have to leave a taildragger untied, then I will try to tail it into the wind.

I have made effective exteral control locks for both of my planes. I do not apply cockpit control locks. I do like the Cessna Caravan external rudder lock - Cessna hsa learned!

c100driver 23rd Apr 2015 01:35

Never tail into wind!

Aircraft are designed to take 100 mph plus airflow from the front, that is how they fly!

I have seen photographs of cubs, auster etc in rows but back to back after a huge storm front passed. Most the the aircraft tail into wind had substantial damage with broken rear spars and bent tail surfaces. Aircraft into wind were damaged by the tail into wind aircraft, but were undamaged by the storm itself.

If you are in for a big blow then bury the nose wheel in a hole for a tri gear or bury the mains in a tail wheel aircraft.

piperboy84 23rd Apr 2015 04:25

Heres an interesting story about an air crash that was caused by a smaller aircraft being subjected to jetblast while parked up which frayed the control cables.

Air Moorea Flight 1121 - Wikipedia, the free encyclopedia

BroomstickPilot 23rd Apr 2015 05:07

Useful NZ CAA Document
 
Hi Guys,

Some years ago the New Zealand CAA produced a document called 'Secure Your Aircraft'.

This was available on the NZCAA website.

I dare say it is probably still there and available to anyone who wants it.

Regards,

BP.

c100driver 23rd Apr 2015 05:59

https://www.caa.govt.nz/Publications...5_Sept-Oct.pdf

CAA Vector magazine on aircraft tie down is still available.

Car RAMROD 23rd Apr 2015 11:26

Here is an interesting fact for those that think control locks will hide damage caused by jet blast.

Control surfaces, hinges, mounts etc subjected to the same jet blast but left unsecured can also have hidden damage when you do your preflight!

Don't believe me? Well, Beechcraft communicated recently to owners and operators specifically about damage to the B200 rudder attach bolt (which cannot be seen unless you remove the rudder) due to jet blast slamming unsecured rudders against stops.

Control locks by nature are designed to take the force and prevent the forces being transmitted to the linkages and cables.

And for my money it's (don't do tail draggers personally so my comments do not relate to them) always parked into wind (well, as far as is practical). After all, the air was designed to go over the surfaces that way.


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