[Canberrauav] Parachutes

Bernard Davison bernard at gondwana.com.au
Thu Feb 19 21:55:00 EST 2015


G’Day Guys,

I’ll be heading up from Candelo so it will take me about 2 - 2 1/2 hours to get to CMAC.
I guess I can be there around 12:30 - 1.
I’m happy to meet elsewhere also.

I can’t see anything in the discussion / desired results that makes it sound hard/impossible/made of unobtainium. All the parameters “seem" reasonable.

I look forward to meeting you on Sunday.

Cheers,
Bernie.


> On 16 Feb 2015, at 10:45 pm, Andrew Tridgell <andrew at tridgell.net> wrote:
> 
> Hi Bernard,
> 
>> I think I can be in Canberra after noon on the 22nd.
>> I hear your airframe is ~5kg
>> What's your expected airspeed? 100km/h?
>> What's your desired descent rate? 
>> How stable do you want the descent? Swinging is okay, slight swing, vertical descent..what's you're desired pack volume?
> 
> As Chris said we're just really wanting to gain experience. My guess is
> we'll start with 3 test airframes, the RangerEx, the Talon and a
> Boomerang.
> 
> We expect the aircraft will be under 4kg, but it will vary a bit with
> payload. Cruise speeds will be between 30 and 40 knots. We would lower
> the airspeed a lot before releasing the chute, so I'd expect the chute
> release to be at below 25 knots.
> 
> We're not really sure what a good descent rate will be for these
> aircraft. Jack did some drop tests with the Boomerang that indicate that
> 5m/s may be acceptable, but the Boomerang has a tough undercarriage. I
> think we'd like to get under 4m/s, but we're really need to judge it by
> trying it and seeing if we get any damage in our tests. We may need to
> change the undercarriage a bit to make it better for vertical drops.
> 
> As far as stability goes, we don't mind if it swings a bit as long as it
> isn't enough for it to catch and damage a wing on landing. The foam
> wings aren't very tough.
> 
> We haven't thought about pack volume. We plan on buying a 62 and 70 size
> fruitychute to start with, then learning by experimenting:
> 
>  http://fruitychutes.com/buyachute/drone-and-uav-parachute-recovery-c-21/fixed-wing-bundle-c-21_22/fixed-wing-recovery-bundle-12lbs-5kg-15fps-p-114.html
>  http://fruitychutes.com/buyachute/drone-and-uav-parachute-recovery-c-21/fixed-wing-bundle-c-21_22/fixed-wing-recovery-bundle-15lbs-68kg-15fps-p-115.html
> 
> It would be great to chat to you about parachutes if you are out at CMAC
> on the weekend! We can show you the planes we're planning to test
> with. What time do you think you will be there?
> 
> Cheers, Tridge



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