another Skylane-inspired mod? Tie-down rings?

[delusional]

now that we have the stall warning, why not some proper Skylane-style tie-down rings? Retractable, I mean.

Anybody know if this is feasible or already done it?

[N941WR]

You would need to add some structure to support the retractable tie down rings.

The Van's rings are simple and light. The doublers Van's includes in the kits supports the aileron bell cranks, provides a place to screw in the tie down ring, and is a hard point for jacking.

I'm thinking Cessna could learn something from Van's.

[airguy]

Originally Posted by N941WR

I'm thinking Cessna could learn something from Van's.

HAHAHAHA!!! That's putting it mildly!

[rocketbob]

Originally Posted by delusional

now that we have the stall warning, why not some proper Skylane-style tie-down rings? Retractable, I mean.

Anybody know if this is feasible or already done it?

Yes it is feasible. I've always thought that a more outboard location for the tiedown rings would provide advantages that would work better than the current location that attaches to the spar strips.

[Greg Arehart]

My tiedowns are already "retractable" - I simply unscrew them when I'm ready to fly. No fuss, no muss.

greg

[roee]

Originally Posted by N941WR

I'm thinking Cessna could learn something from Van's.

Originally Posted by airguy

HAHAHAHA!!! That's putting it mildly!

I agree with that general sentiment. HOWEVER, Van's tie down design does leave some to be desired.

Mechanically it is crude, as the base of the tie down ring sits against unsupported skin (there's an air gap between the skin and the threaded mount) and the skin will distort if the tie down ring is tightened down. And there is just barely not enough gap between the skin and the mount for a jam nut, so in practice this means that the tie down rings can't be tightened down properly.

Aerodynamically it is also crude, as the rings sit out there in the breeze and make drag. I don't know how much, or how significant it might be in the bigger picture. But as obsessed as the RV community is with drag reduction, it's surprising that this particular instance generally goes unnoticed.

Originally Posted by Greg Arehart

My tiedowns are already "retractable" - I simply unscrew them when I'm ready to fly. No fuss, no muss.

One could consider the tie down rings removable by unscrewing them, but that's only good for perhaps a few hundred cycles before the threads in the aluminum mounts will be toast, and they won't be easy to replace. So unscrewing them is reasonable to do for an occasional long trip or air race, but probably not something you want to do for every flight.

Not trying to be overly critical, but yes, there is still room for improvement. And that's a good thing. It means that someone here can take the initiative and come up with a better solution. And I haven't seen the tie downs on a 182 so I can't comment on them specifically, but yes, on a few rare occasions Van's could even learn something from --gasp!-- Cessna.

[arffguy]

Yeah, I have seen it done on an RV. No, I don't know the innards of the wings and I can't find my photos of the external view yet. I can tell you, after years of working in the FBO business, that the springs on many Cessnas were frequently broke and the things would not retract properly anyway.

[rvmills]

Originally Posted by rocketbob

Yes it is feasible. I've always thought that a more outboard location for the tiedown rings would provide advantages that would work better than the current location that attaches to the spar strips.

With ya there Bob...have been pretty close to my pitot tube a couple times with tie-down chains. I'm wonderin' if the location was chosen as a point of max-strength (and min-damage potential) on the wing to mount the tie-down.

Originally Posted by Greg Arehart

My tiedowns are already "retractable" - I simply unscrew them when I'm ready to fly. No fuss, no muss.

Originally Posted by roee

Aerodynamically it is also crude, as the rings sit out there in the breeze and make drag. I don't know how much, or how significant it might be in the bigger picture. But as obsessed as the RV community is with drag reduction, it's surprising that this particular instance generally goes unnoticed.

One could consider the tie down rings removable by unscrewing them, but that's only good for perhaps a few hundred cycles before the threads in the aluminum mounts will be toast, and they won't be easy to replace. So unscrewing them is reasonable to do for an occasional long trip or air race, but probably not something you want to do for every flight.

I was thinking along the same lines as Greg...but mine only go in when I need them (X-C and need to tie down, etc). Not sure if that is the norm or the exception for the fleet, or somewhere in between. Concur with the drag-averse nature of the community (as it should be!)...and dern it, I forgot to tape the those two holes before the last race!

It's been a pretty low percentage usage item though (in my case), so hopefully the threads will last a good long time (hadn't considered that...hmmm, I better be careful! )

It's an interesting idea though to be sure. Like replacing the ring mounts though, might be a tough chore in a completed airplane. Cool to think about though!

Cheers,
Bob

[Bubblehead]

One thing I like about the standard Van's tie downs is that you can back them out a little to put the pull of the tie down rope in line with the eye of the ring. The ring is stronger in that direction than if the pull were from the side.

What I like is also what I don't like. You cannot screw the ring down tight to the skin so the shoulder helps reduce the bending moment at the threads.

On the Cessna system, the high wing and wide distance between the tie downs allows the tie down ropes to pull almost straight down on the retractable "blade." I've tied my RV-8 down at a lot of airports and the low and short wing with tie downs relatively closely spaced is a disadvantage because the pull from the tie down ropes is almost always at a flat angle that puts a lot of bending moment on the tie down rings.

I would like a retractable blade if it were oriented properly to the direction of the tie down ropes. I'm not sure that can be reliably done because of the variations in the spacing of tie down ropes at airports.

[Crossbow]

Originally Posted by Greg Arehart

My tiedowns are already "retractable" - I simply unscrew them when I'm ready to fly. No fuss, no muss.

greg

Thanks! I was thinking about the same thing myself.