Chute recommendations

Discussion on ground control/GSE and recovery equipment. This includes launch pads, triggers, chutes, streamers etc. Includes other items such as simulation and other computer software, etc.

Moderator: Moderators

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Chute recommendations

Postby strud » Sun Jun 30, 2019 10:09 pm

I'm in the midst of designing a 4" vehicle with two configurations, with dry/recovery masses of say 11 and 6kg.

After looking up a few sources of commercial chutes for these masses, it seems I could be up for between US$200 and US$300 for the likes of an IRIS from Fruity chutes and similar. This one (84") seems to pack down to a rather 'compact' volume of only 8.5" in length within a 4" tube !!
https://fruitychutes.com/buyachute/l3-elliptical-72-to-120-c-8/84-custom-parachute-23lb-20fps-p-5.html

The LOC angel chutes look more economical, but the below table shows them to be packing down to much larger volumes
http://www.b2rocketry.com/PDF%20files/SkyAngle%20Packed%20Length.pdf so between 17 to 25"

Rocketman chutes seem to be rather economical (between US$70 for 8ft and US$120 for 10ft), although their Cd is much lower hence the need for a larger chute
https://the-rocketman.com/chutes.html/
Interestingly they are packing down to a smaller volume than for the fruitychutes (ie for the chute size required to meet 15ft/s decent rate)

eg 8ft chute (for 6kg empty mass) packs down to 6.5" length, 10ft chute (for 11kg enpty mass) packs down to 8.5"

Before I consider making my own (the amount of labour in this is HUGE but I probably need to consider the alternative to be AU$800 on chutes) does anyone have suggestions on other chutes commercially available?

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2777
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Chute recommendations

Postby OverTheTop » Mon Jul 01, 2019 7:23 am

Hi Strud,
I have been a fan of the Fruity Chutes product of recent times, and I also use the Sky Angel chutes frequently. For Fruity Chutes the cost is quite high, especially going to the lightweight/small volume chutes, but quality is great too :wink: .

I am about to place an order with Rocketman for a number of chutes. He seems to be getting good comments on TRF and prices are reasonable.
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

User avatar
CATO
Mr Smiley
Mr Smiley
Posts: 2034
Joined: Thu Dec 24, 2009 6:20 pm
Location: Sydney, NSW
Contact:

Re: Chute recommendations

Postby CATO » Mon Jul 01, 2019 7:37 am

Hi Strud,

I have utilised the 60” IRIS Ultra chute for my Hyper LOC 835 https://forum.ausrocketry.com/viewtopic.php?f=6&t=4234&hilit=Iris, a great chute, very compact.

9BAB2A7C-C9CA-4B26-8746-0CEAF93AF485.jpeg
"In thrust we trust"

AMRS 21 L3 RSO
TRA 07459 L3

Impulse:
2019: 7,898 Ns (54% M)
Ns 18: 14,767; Ns 17: 5,973; 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: M1.14

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Re: Chute recommendations

Postby strud » Mon Jul 01, 2019 11:13 am

Thanks CATO and OTT

I did some late night surveying of the commercial offerings last night and there's a lot on offer but selection is not straight forward.....

For the lighter of the two vehicles, the Rocketman std chute 84" looks to be quite suitable with a cost of US$65, packed length at 4" dia of 3.85" and a 20fps load of 15lbs.

https://the-rocketman.com/chutes-html/

Since this only has 4 shroud lines I guess this helps with reduced volume, but maybe makes them a little less robust/able to survive non-ideal deployments.....

For the heaver version, keeping the packed volume down is important so the airframe length does not grow. I would need to consider one of the more compact designs such as the Iris ultra IFC-72-S
https://fruitychutes.com/buyachute/iris-ultra-compact-chutes-c-18/iris-ultra-72-compact-parachute-28lbs-20fps-15lbs-15fps-p-88.html?zenid=GD5pFmC2i3Syh6e03wKak0

or at a similar (high) price, the Rocketman high performance 72"
https://the-rocketman.com/rocketman-ultra-light-high-performance-parachutes/

with a crazy packing length at 4" dia of 1.28" :shock:

Anyway being realistic I would have very little chance to make my own chute to achieve the high Cd and low packing volumes these ones get to, so I guess that I just better save up my coins....

OTT, please let me know what you think of the Rocketman chutes when you get them, will hold off my orders until then.

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2777
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Chute recommendations

Postby OverTheTop » Mon Jul 01, 2019 12:23 pm

I would suggest you email rocketman and ask any questions. Chutes can be customised and they are very helpful with answering any questions you might have.
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

User avatar
CATO
Mr Smiley
Mr Smiley
Posts: 2034
Joined: Thu Dec 24, 2009 6:20 pm
Location: Sydney, NSW
Contact:

Re: Chute recommendations

Postby CATO » Mon Jul 01, 2019 12:32 pm

"In thrust we trust"

AMRS 21 L3 RSO
TRA 07459 L3

Impulse:
2019: 7,898 Ns (54% M)
Ns 18: 14,767; Ns 17: 5,973; 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: M1.14

User avatar
Wingnut
Engineer
Engineer
Posts: 1025
Joined: Mon Nov 12, 2007 9:39 pm
Location: Brisbane

Re: Chute recommendations

Postby Wingnut » Thu Jul 04, 2019 12:51 pm

I have two Rocketman chutes; 6-foot (72 inch) and 8-foot (96 inch). I can't fault the quality or operation of my Rocketman chutes. However, I wish they could pack down a bit smaller in a 4 inch airframe. I can do you some packing volume tests on my two chutes if it will help.

Bye,
Mike

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Re: Chute recommendations

Postby strud » Thu Jul 04, 2019 3:05 pm

Hi Mike

Are they the 'std' 4 line chutes?

Very interested to know what you think their packing length in a 4" tube is since on their website the packing length for those is quite small. I figured that was because of the low number of lines....

User avatar
Wingnut
Engineer
Engineer
Posts: 1025
Joined: Mon Nov 12, 2007 9:39 pm
Location: Brisbane

Re: Chute recommendations

Postby Wingnut » Fri Jul 05, 2019 8:58 am

Yeah, both of my Rocketman chutes are the "Standard" grade 4-line chutes. I'll perform a couple of "pack" tests and post the results on this thread.

Bye,
Mike

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Re: Chute recommendations

Postby strud » Fri Jul 05, 2019 9:56 am

Hi Mike

That would be most appreciated

Here is their packing instructions, you may already have seen...

https://the-rocketman.com/packing/

If you look at their specs for packing volume, these std chutes are meant to be quite good with the 84" (7ft) into 3.85" length for a 3.9" ID tube.

I have contacted them for comment and further information on total size required with a deployment bag.

User avatar
Wingnut
Engineer
Engineer
Posts: 1025
Joined: Mon Nov 12, 2007 9:39 pm
Location: Brisbane

Re: Chute recommendations

Postby Wingnut » Fri Jul 05, 2019 8:47 pm

Hi,

I've just completed a couple of "pack" volume tests with my standard 72" and standard 96" Rocketman parachutes.

Here is roughly the procedure that I followed for each test:
  • I folded the parachute chute and shroud lines in a fashion similar to that recommended in the instructions provided on the Rocketman web site.
  • During the folding process, I compacted the chute as tighly as I could possibly achieve.
  • In each case, the diameter of the chute package was narrow enough to slide easily inside a 3.9" airframe under the force of gravity; no manual force was required push the package to the bottom of the airframe section. Chutes that are jammed into airframes will not eject in flight. So, there was not point cramming a wide diameter chute package for these tests.
  • A blulkplate was inserted into the airframe on top of the chute package. I measured the length of airframe tube from the top of the bulkplate without applying any force to compress the package inside the airframe.
  • This measurement represents the linear length of 3.9" airframe tube that was occupied by the packed parachute.

TEST #1 - standard 72" Rocketman parachute
    The first test was made with just the 72" parachute by itself. The ripstop nylon cloth used on these Rocketman chutes is very slippery. Folding the plain chute into a tight package was quite challenging and even more difficult to keep it compressed while feeding it into the airframe.
    Linear length of airframe = 165mm

TEST #2 - standard 72" Rocketman parachute plus Nomex Blanket
    The second test was the 72" parachute wrapped in a 600mmx600mm Nomex blanket. This size blanket was absolute overkill for the 72" chute, but it's the standard set-up on my BSD Thor rocket. The blanket make compressing and holding the chute package a lot easier.
    Linear length of airframe = 175mm
    There was only a minimal increase in package size with the blanket because the package could be compressed a lot more in the blanket.
      72 wtih blanket.jpg
      72 wtih blanket.jpg (225 KiB) Viewed 240 times

TEST #3 - standard 72" Rocketman parachute plus Nomex Blanket plus shock cord
    The third test was more of a real-world scenario with the 72" chute and 8 mentres of 9/16 inch (0.56") tubular nylon shock cord wrapped in a 600mmx600mm Nomex blanket. This is the standard set-up for my BSD Thor.
    Linear length of airframe = 245mm
      72 with blanket and cord.jpg
      72 with blanket and cord.jpg (233.71 KiB) Viewed 240 times

TEST #4 - standard 96" Rocketman parachute
    The fourth test was just the 96" chute by itself.
    Linear length of airframe = 200mm

TEST #5 - standard 96" Rocketman parachute plus Nomex Blanket
    The fifth test was the 96" parachute wrapped in a 600mmx600mm Nomex blanket. This size blanket was generous for the 96" chute. You could safely use a smaller blanket if space is tight.
    Linear length of airframe = 225mm
      96 with blanket.jpg
      96 with blanket.jpg (248.19 KiB) Viewed 240 times

TEST #6 - standard 96" Rocketman parachute plus Nomex Blanket plus shock cord
    The sixth test was the 96" chute and 8 mentres of 9/16 inch (0.56") tubular nylon shock cord wrapped in a 600mmx600mm Nomex blanket.
    Linear length of airframe = 310mm
      96 with blanket and cord.jpg
      96 with blanket and cord.jpg (250.06 KiB) Viewed 240 times

I hope this feedback is helpful.

Bye,
Mike

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Re: Chute recommendations

Postby strud » Sat Jul 06, 2019 7:47 am

Hi Mike,

Super helpful indeed, many thanks for going to that effort.

The results you have are practical and are somewhat larger than stated on the manufacturers site so good to know and will be very helpful in planning the recovery bay dimensions.

CS

strud
Engineer
Engineer
Posts: 957
Joined: Thu Oct 02, 2008 7:37 am
Location: Central Tablelands, NSW

Re: Chute recommendations

Postby strud » Sat Jul 20, 2019 8:05 am

So based on real feedback and my best analysis, I've gone ahead and ordered one of these with a deployment bag:

https://fruitychutes.com/buyachute/iris-ultra-standard-chutes-c-29/iris-ultra-72-standard-parachute-28lbs-20fps-p-143.html

Plan is to get this in hand shortly and mock up the recovery harness etc to work out lengths required etc. The main will most likely be retained by a device such as the ARRD or Tender Decender eg https://fruitychutes.com/buyachute/recovery-tethers-line-cutters-c-9/anodized-aluminum-l2-recovery-tether-up-to-60lb-rockets-p-50.html.

Next point of focus for the recovery is the drogue.

From the reading I have done so far, it seems aiming for about 5% the area of the main is a good starting point for the drogue. In addition to this, aiming for a decent rate in the 100fps range is recommended, although this depends on the mass distribution and fin size since falling too fast can tend to make the rocket fly tail first and head off into the next state.... (have seen this in action).

I likely have a suitable cross form drogue on hand for an early 'PoC' flight, but will take my time to determine a very robust drogue system for the higher speed higher altitude flights which are much more likely to have high speed drogue deployment.


Return to “Support & Recovery & Misc.”

Who is online

Users browsing this forum: No registered users and 2 guests