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.

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strud
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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 !!


The LOC angel chutes look more economical, but the below table shows them to be packing down to much larger volumes
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?

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OverTheTop
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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.
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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 , a great chute, very compact.

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strud
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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.



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


or at a similar (high) price, the Rocketman high performance 72"


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.

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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.
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Re: Chute recommendations

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

Ask for "Buddy" :)


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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

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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....

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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

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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...



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.

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Re: Chute recommendations

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

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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

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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:



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 .

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.


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