new high-speed drogue design.

[AndyC]

Thought I'd share this, and see if there's any interest.
I've designed built, and tested this new design for a drogue chute (see atteched pic).
It looks complex, but actually comprises just 3 pieces of fabric, and 6 - 8 shroud lines. The benefits are very slow inflation (ie low opening shock) and high stability.
I've tested it at 50mph, attached to my car, and it takes between 5 and 7 seconds to fully inflate. Due to the short shroud lines, tangling is virtually impossible. Once fully inflated it is very stable. However during inflation it is prone to spin a little - so a swivel fitting would be a good idea.
The prototype is 18" diameter.

Any thought and comments appreciated

Andy.

 

[powderburner]

These things are also used on the tail end of some aerial bombs, to retard the weapon and let the parent aircraft get clear.

While it is interesting to hear that your ballute design is 'slow opening' when towed behind a car (effectively, infinite mass pulling the device forward), I would be much more interested in learning how reliably it opens when towed behind a model rocket.
Keep us posted?

 

[AndyC]

Yes - basically a ballute - although ballutes tend to be inflated by valves around the circumference rather than an opening at the bottom. I did this to simplify construction. Logically, the drogue should open even more slowly with the rocket - as even the partially-infalted chute will begin to progressively decellerate the rocket. The drag is somewhat less than a traditional chute, due to the shape, but still plenty to stabilise a falling mass. Since tangling is virtually impossible, reliabilty should be high.

I'll keep you posted.

 

[edwardw]

Would it be possible for the lines to twist and shut off airflow to the ballute?

Edward

 

[AndyC]

I guess that's possible - but hasn't happened yet
Like I said in my earlier post, fitting a swivel ought to ensure this doesn't happen.

 

[edwardw]

I like the design. I had a ballute and then decided to go for a long three line option. Less material and had about the same inflation time. Keep me updated.

Edward