spinning sling loads?

[Boudreaux Bob]

Conex Boxes ride just fine.....

[spinwing]

Mmmm ...

... Conex Boxes ride just fine.....

Yeah under a 'hook' ... speakin of which .,.. where is 'sasless' ??

[John Eacott]

Sometimes the chacons flew just fine, sometimes they spun a bit. No worries unless the doors weren't secured properly and the rating's luggage departed into Mount's Bay



Quite why the military tend toward short strops in conditions where most civilian operators would use long lines, I've never worked out. I've generally found loads on a long line less inclined to spin than those on shorter lines, although a pendulum swing is then more likely.

[aerodoug]

Ant T
thanks - that sounds like a similar size and behaviour to the CONEX?

[aerodoug]

... Conex Boxes ride just fine.....

isn't that a MILVAN container?

[aerodoug]

Sometimes the chacons flew just fine ...

Thanks - that's consistent with some wind tunnel tests the Royal Military College at Shrivenham did inthe 70's, where I think they described the behaviour as 'erratic'.

[John Eacott]

Originally Posted by aerodoug

that's consistent with some wind tunnel tests the Royal Military College at Shrivenham did inthe 70's, where I think they described the behaviour as 'erratic'.

I never had any report of 'erratic' flying characteristics of a chacon, but certainly they sometimes developed a spin (as per the thread subject) without any instability.

Smooth and balanced flying is always the key: I've even done a GCA with a load which flew (as much as we could tell in IMC, according to the crewman watching out of the door) without any problem.

[aerodoug]

I think the report meant 'erratic' as in spinning vs not spinning, rather than its general flight characteristics.

Looking at your photos, I'd seen a comment on an old thread about landrovers spinning, but I wonder whether that depends on the cab configuration?

[brett s]

We usually carried 2 or 3 CONEX containers at a time with CH-47C's (single cargo hook) but I don't remember singles wanting to spin more than anything else.

MILVAN containers were a different story though, didn't work so well until we got D models & multiple hooks.

[Cornish Jack]

I've generally found loads on a long line less inclined to spin than those on shorter lines, although a pendulum swing is then more likely.

Back in the 70s at Boscombe, we did some trials with 'jungle penetrators', heavy, anchor-like devices with strop attachments for crew and SF recoveries. It was attached to the underslung hook on a 300' nylon rope, with 3(4?) dummies attached. Took them out on the Plain and tried increasing speed points. IIRC, we got to 40 kts (load now trailing way behind the t/r) and the load and rope developed what I can only describe as a 'sinusoidal whip'!! Shortly thereafter, it went solo! Not too enamoured of the principle but, I suppose if the baddies are after you it MIGHT offer an option ... but then again!!

[jimf671]

Originally Posted by aerodoug

jimf671

good points - I hadn't though about onboard torque reaction devices.

Still, I'm with you on simple ... putting sensors, actuators and control systems on a load looks good in theory, but I can see all sorts of practical problems in the field.

Currently all about how big a force can you generate and how well you can control it. The target market is clearly for big loads and big cranes. Maybe one day that will be sorted and the attention can turn to helicopters. There is an engineering solution to everything.

Torquer 2 - YouTube