In France you rarely find anything to tie to so the best you can do if you are parked on grass is to use those corkscrews. In Norway, Sweden and Denmark on the other hand you either find eyes flushed into the concrete, or tyres filled with concrete.
On the DA40 the eyes are located at the outboard extremity of the wing. Should the airplane become airborne, or even pull on the tiedowns, I wonder whether that could actually damage the wing given the 11 m arm to the point of attachment to the airframe.
Edit: The arm is actually about 5 m on each side
Peter wrote:
Neither are the blocks of concrete or car tyres filled with concrete – a good number of UK pilots have got airborne with them still attached.
I recall a Swedish AAIB report with a laconic comment about the unsuitability of concrete-filled tyres: “Aircraft are designed to take off with load.”
yep, it depends on the weight of the aircraft. But I never believed weight is so relative. Pictures below are not random, this is procedure at both airports for years…
this is heavy aircraft no need to tie down
make sure to tie down this small aircraft…
It’s not only weather that can be a problem.
A friend was hanging of the wing of his Cessna when the heavy Merlin rescue chopper suddenly arrived and landed close to the parked GA aircrafts.
The other day I was parked close to An ATR42 that I was told was not going to get pushed out but would turn 180 degree on it’s own power.
I always carry quality rope, big aluminium spikes and a rubber mallet.
On a hard apron I also use the car tyres with concrete. Even if the the aircraft is designed to take of with a load, any add on to the weight will also require more force to lift it.
I suppose there are two concerns with the concrete blocks. 1) will I forget it’s there and take off with it and 2) will it do the job of stopping the aircraft from blowing away?
It seems to me possible that the answer to 2) may be ‘yes’ even if the answer to 1) is ‘yes’ too. If you can stop a wing lifting a little bit, you may be able to stop it lifting a lot, such that the wind really gets under it and lifts it away. I’m sure the concrete blocks will provide some protection. The question is ‘how much’? I’d be interested to know the answer.
Incidentally you can hold a hang-glider quite happily with 1 hand in quite strong winds, despite them having as much wing area as a Cessna 152, by holding the front wires and letting the glider fly itself into the wind. If the wind tries to lift the wing, because you’re holding it at the nose, the angle of attack is decreased. All you really need to overcome is the parasitic drag and the induced drag of lifting 30kg – neither of which will amount to that much.
My daughter had one of the corkscrew things for tethering her horse to stop him eating the whole field. Very soon he took exception to this and very gently lifted his head. The corkscrew just uncoiled and came out of the ground as a straight if wobbly piece of wire! Obviously aviation quality ones are made of better grade materials. The one in this photo attached to a 152 is much stronger and only opened at the top, allowing the rope to drop out.
I carry and use occasionally the ‘claw’, a thing with 3 angled pins. I’ve no idea if it would actually work with a potentially 1T load, but it ensures that you get plastered with mud on damp days and hopefully would look good on the claim form. I’d rather someone else’s plane blew into mine than mine into theirs. There is obviously a finite risk with the claw and other gadgets that the tools used to install and remove them will somehow spring up and puncture a fuel tank.
You might be able to fly with a tire filled with concrete, but there is no way you will be able to taxi with it and not recognize something is terribly wrong, or able to taxi at all. A microlight (Zenair CH 701) in Alta used to be tied down. It was tied under the wing at the strut/wing interface. It took off, flew to 2-300 feet before the wing folded. Both killed. The reason was fatigue fracture at the tie down point. The struts are not designed for the hard sudden pulls from the rope (they tied it wrong, just to be precise).
You might be able to fly with a tire filled with concrete, but there is no way you will be able to taxi with it and not recognize something is terribly wrong
http://news.bbc.co.uk/1/hi/england/tyne/6643891.stm – though it was only a cubic foot and not a whole tyreful (30cm).
Holy sh!t !!!
LeSving wrote:
You might be able to fly with a tire filled with concrete, but there is no way you will be able to taxi with it and not recognize something is terribly wrong, or able to taxi at all.
There was a tale I was told at ENKJ when I trained for the PPL about a Saab Safir that taxied and took off with a concrete blocked tied to the tail, did one circuit and landed again. So, if you believe that tale…
LeSving wrote:
The reason was fatigue fracture at the tie down point. The struts are not designed for the hard sudden pulls from the rope (they tied it wrong, just to be precise)
That is a good point. The way you tie it down, and the type of rope you use. I’ve seen aircraft tied down with nylon ropes. I would think that cannot possibly be good and that it would be better to use something more elastic?
