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Fuppylodders

Aircraft recovery chute?

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mrubin

... Have you researched spin recovery parachutes? I know those are sometimes used in aircraft testing. It might not be exactly what you are looking for, but it might be a good place to get started.

"

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Sure, use a mortar to deploy a spin recovery chute, wait a few seconds (or until velocity has fallen below 200 knots) then use the spin recovery chute as a pilot chute to deploy the landing chute.

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" ... Another challenge you have is dealing with fire. It happens a lot around aircraft emergencies. Those chutes and there attachment points would have to withstand high heat while aircraft descended under canopy(s) with passengers breathing fire feeding oxygen? ...."

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There are plenty of materials that resist fire better than nylon ... cotton, wool, Kevlar, Nomex, etc.

To reduce the risk of spinning propellers cutting bridles/risers, BRS installs Kevlar risers.
I have also packed a recovery chute for an ultra-light airplane that had the risers attached to a steel cable ... again to prevent the propeller from cutting the risers.

Back when the century-series fighter planes were fashionable, they used to make landing drogue chutes out of Kevlar. The y used Kevlar primarily because the air is so hot behind jet fighter engines.

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I think what he means is that there have been a couple of saves. I recall the first one which was on the north side of Dallas. It was a control failure, I think an aileron. It was unlandable. The chute let him down softly in a field. No injuries and virtually no damage to the plane. There have been a few since then but I don't recall how many. In short it's proven it self to be a workable system. Which is a good thing. The Cirrus in not a plane that you can land off field. It's like a lot of the smaller experimentals. It's a fast little thing with a smaller economical engine. They're able to get that speed by reducing the drag. Like a lot of the experimentals they do it by cutting off any thing that sticks out into the wind... like the wing. It was not able too meet the stall speed requirements for certification. The only way they could get it certified was to argue that they had an "alternate means of compliance" in the event of a off field landing. Hence the BRS.

Not saying it isn't a nice plane. Not saying I wouldn't like to have one. But it is what it is.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Doug_Davis

How would a fabric/material like cuben stack up in use for a purpose like this versus nylon?



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Cuben fabric is a composite of Kevlar,carbon, UHMW polyethelene, etc. Some of those materials (Kevlar) have better heat resistance than nylon, while polyethelene quickly distorts under heat. The proportions vary with the intended use of the final fabric.

The challenge is to define exactly which combination of yarns you want in your cuben fabric????????????

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RiggerLee

The chute let him down softly in a field. No injuries and virtually no damage to the plane.



I recently took a ride in a Cirrus with a friend. He told me about the CAPS system -- apparently pilot is required to brief all passengers on how to use it -- and naturally I had questions... The most interesting part to me was that, if the CAPS is deployed, the airframe is essentially totalled; it is sacrificed to absorb some of the shock of the parachute. I don't know for sure that this is the case, it could be true that it doesn't really damage the plane much, but this is what I was told.

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RiggerLee

I think what he means is that there have been a couple of saves. I recall the first one which was on the north side of Dallas. It was a control failure, I think an aileron. It was unlandable. The chute let him down softly in a field. No injuries and virtually no damage to the plane. There have been a few since then but I don't recall how many. In short it's proven it self to be a workable system. Which is a good thing. The Cirrus in not a plane that you can land off field. It's like a lot of the smaller experimentals. It's a fast little thing with a smaller economical engine. They're able to get that speed by reducing the drag. Like a lot of the experimentals they do it by cutting off any thing that sticks out into the wind... like the wing. It was not able too meet the stall speed requirements for certification. The only way they could get it certified was to argue that they had an "alternate means of compliance" in the event of a off field landing. Hence the BRS.

Not saying it isn't a nice plane. Not saying I wouldn't like to have one. But it is what it is.

Lee



I am aware of the requirement for the recovery chute for certification. Gary Douris was making the canopy for a number of years. His shop was next to Elsinore. I was jumping one Saturday and he wandered over and we started shooting the shit. I asked him how business was doing and he said great. There had been 4 saves in the last few days.

Sparky
My idea of a fair fight is clubbing baby seals

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I think there are too many variables to predict the level of damage that you might see on landing. Was there one person on board or four? Was it full of fuel or empty? Was there wind. Was it over hard rocky ground, 50 ft. trees, or a deeply plowed muddy field in north TX? Then comes the legal issue of whether they would ever let it fly again. I have no doubt that they state that any airframe saved is grounded forever. The liability to do other wise is just too high.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Hey guys, sorry I am only just popping my head in now, I've had a busy weekend.
It's great to see the responses that are coming, as well as the different ideas, and the knowledge that is coming out that I would not have been able to find/understand otherwise!

Yes, I have already exhausted my questions with BRS, they were the first company I spoke to. Already not knowing anything much about parachutes, my questions were more directed around theories of ideas rather than the parachutes themselves, so I can't say I noticed what you (RiggerLee) mentioned of them. However, the answers I did get led me to believe that ram air recovery systems isn't impossible, but very possibly possible (does that even make sense?). Unfortunately, I'm not getting much of a response from other parachute companies, hence me finding somewhere I can converse to ask opinions and such (here)!

Currently reading the website mrosparky linked (I'll get to the others as well ), a very interesting read, and no doubt helpful in allowing me work out things I couldn't before.

I do not personally believe it would be 'too' difficult in implementing a guidance system, automated or controlled through semi automated/wireless receivers controlled by the pilot, as they are already available. So the technology is already there, perhaps just some tweaking/adjusting/advancement may be required to adapt it to an aircraft.

Should I need to, I will look at an even smaller aircraft than a Learjet85, until I find a suitable candidate... or not...

@RiggerLee
That video... the sound of the rocket going up!
Then seeing the rocket parachute into vision like that, something comical about seeing it glide in from the side of the screen like that, had a chuckle watching it! Reminds me of Thunderbird 3 :D
That clearly was guided, but was it automated, or was it controlled by a person with a receiver? (I read something about software, so I assume it was automated?)

Do you think it may be possible to use a slider to reduce the opening of the canopy by so much, alongside using a drogue chute to help slow it down enough that allows the opening of the ram-air chute at a safe speed?

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It was an autonomous guidance system built by Waymore. Its the same AGU and software used by the military for their precision drops. It can be flown manually from the ground. or left on automatic. We never had to take over manually. The soft ware always brought it back right to the landing area even when the canopy was damaged on opening. Even if you break a control line it will reconise that and bring you home in a left or right hand pattern. Assume. It doesn't really give you a since of the scale. That rocket is 34 ft. long and 20 in. in diameter.

I'm not sure I understand your other question. There are a number of techniques with rounds that can allow you to control the openings even at high speeds. Like multiple loops holding the throat of the canopy to a certain diameter. They are cut by timers allowing the canopy to open progressively over say nine sec. Even then the stresses at the top of the canopy can be harsh. It can be better to use a drogue or smaller canopy to slow it down to a more reasonable speed before trying to open a large light weight, that's relative, canopy. The fundamental design fo the first canopy, the drogue, is fundamentally different from the final main canopy. Think ribbon canopy vs. G12. Look them up.

Ram airs are fundamentally not as for giving. Or lets say the technology has never been developed in that way. If you want to open a ram air your best bet is to get the speed down to some thing reasonable. Say 150 or less. The slider is the standard method of reefing and those numbers kind of represent the limits of it. People have tried to cheat by using cutters to hold up the slider and other things of that nature but it really interferes with the natural progression of the opening. It just doesn't translate to a ram air that well. Airborn systems has a patent on a technique for using multiple cutters to open a large ram air canopy in stages with out the use of a slider. They actually made this work on some very large canopies. It might be your best chance to push the speed limitation of a ram air. But even then it's going to be hard on the canopy. Ram airs are also more finicky about being stable during opening. I think you would need a two stage system in ether case.

The easiest and most certain way to do this would be to mortar deploy a fairly large conical ribbon canopy to reduce the airspeed and stabilize the plane. And then use it to deploy a cluster of one or more G12 round canopies or something similar depending on the weight.

This is off the shelf technology. There is prior art on this. You don't have to reinvent the wheel. There is data available for this technology. All the answers to your questions are there for the taking. There is a lot of interest in ram airs for cargo but this is still in development. If you want to try to push that into the kinds of weights and speeds that you're talking about then you are blazing a brand new trail out over the horizon into unknown lands. Now I like that shit. I think it's fun. But you're not going to sell that to a aircraft manufacturer.

If you want to learn all about big ram air cargo call waymore in Phoenix Az. See if you can get a hold of Mark if he's in country. He's a really nice guy and is in the center of all of this. Tell him hi.

Sorry it's Wamore. these guys.

http://www.wamore.com/News--Events/Wamore-s-JPADS-2K-AGU-Featured-at-Smithsonian.aspx


Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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evan85

***The chute let him down softly in a field. No injuries and virtually no damage to the plane.



I recently took a ride in a Cirrus with a friend. He told me about the CAPS system -- apparently pilot is required to brief all passengers on how to use it -- and naturally I had questions... The most interesting part to me was that, if the CAPS is deployed, the airframe is ... totalled ...

................................................................................

First, you burn out the rocket motor.

Secondly, you tear off the cover strips that protect the risers, where they wrap around the sides of the cabin.

Thirdly, the canopy has to go back to the factory for repack.

Fourthly, you probably damaged the undercarriage by landing hard, on steep terrain, which might also damage the wingtips, etc.

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mjosparky

***I think what he means is that there have been a couple of saves. I recall the first one which was on the north side of Dallas. It was a control failure, I think an aileron. It was unlandable. The chute let him down softly in a field. No injuries and virtually no damage to the plane. There have been a few since then but I don't recall how many. In short it's proven it self to be a workable system. Which is a good thing. The Cirrus in not a plane that you can land off field. It's like a lot of the smaller experimentals. It's a fast little thing with a smaller economical engine. They're able to get that speed by reducing the drag. Like a lot of the experimentals they do it by cutting off any thing that sticks out into the wind... like the wing. It was not able too meet the stall speed requirements for certification. The only way they could get it certified was to argue that they had an "alternate means of compliance" in the event of a off field landing. Hence the BRS.

Not saying it isn't a nice plane. Not saying I wouldn't like to have one. But it is what it is.

Lee



I am aware of the requirement for the recovery chute for certification. Gary Douris was making the canopy for a number of years. His shop was next to Elsinore. I was jumping one Saturday and he wandered over and we started shooting the shit. I asked him how business was doing and he said great. There had been 4 saves in the last few days.

Sparky

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Yes!
Gary told me about some of the test-flights that he flew in a Cessna 150. Gary described how they deployed the BRS at high altitude, rode it for a few thousand feet, then cut-it-away for a normal landing pattern and wheel landing.
"It was quite the E ticket ride!" laughed Gary.

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Sarcasm alert!

What do you mean by saying that reefing ropes don't work on ram-air canopies?????
I have dozens of jumps on a Strato-Cloud equipped with ropes-and-rings reefing.
It was a bitch to pack!
Holy "pack volume" Batman!
My fingers bled after every pack job!
Something about stuffing an extra 64 feet of rope into a container originally designed for a slider-equipped Strato-Cloud.
64 feet was not quite long enough for a rope, because it had a bad habit of pulling the end-cells closed multiple times during the canopy ride.
The only saving grace was that it opened soft enough to deploy in a full track!
If I never have to pack another ropes-and-rings canopy in this lifetime, it will be soon enough!

Hah!
Hah!
Hah!

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Thank you RiggerLee, this is again, exactly the kind of information I am after.
I was able to tell the size of the rocket from the ladder (looked like a ladder?) next to it. Certainly impressive!

My problem is I always aim (too) high and have to work my way back down to earth... so, yeah I was kind of secretly hoping to produce something that may have had some sort of skeleton to the idea... but I know what I am like, so I will settle for what I can realistically achieve given the timescale.
Being in the UK, it'll be an expensive phonecall! So I may just email them and ask to speak to Mark saying who sent me.

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The parachute on a cirrus is designed to save the passengers and NO I have not used mine. Using it generally totals the airframe. It is for use in an Emergency when the pilot believes he has lost control of the plane and/or is contemplating an off airport landing (such as might occur in an egine out scenario).
The same is true of all BRS installations, as far as I know. The purpose is to save passengers, not necessarily save the airplane.
The track record of "saves" when cirrus airplane pilots have opted to use the chute is impressive. If pulled, it has worked probably greater than 95% of the time.

dwh

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That was awesome. Not only did it land right there in front of you but it didn't even fall over. That's the coolest thing I've ever seen.

You're gonna have to spill more details. Did the rocket have any kind of guidance system? Was 600 lb. the empty weight? If so what was the initial weight? What kind on nozzle? What size canopies were you using there? Altitude? Did it carry any thing?

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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RiggerLee

That was awesome. Not only did it land right there in front of you but it didn't even fall over. That's the coolest thing I've ever seen.

You're gonna have to spill more details. Did the rocket have any kind of guidance system? Was 600 lb. the empty weight? If so what was the initial weight? What kind on nozzle? What size canopies were you using there? Altitude? Did it carry any thing?

Lee




I wasn’t there when it launched. I built the system for Gates Brothers Rocketry. I ended up building 3 or 4 systems from them.

It had no guidance system and the empty weight was 600 lb. When it reached apogee the nose cone blew off deploying an 18 foot modified cross form. Apogee was about 5,400 feet and I wanted the smaller chute to allow it to come down fairly fast and not get lost to the winds. At 1,500 feet an ARRD device released the nose cone and the cross form deployed the 2 mains. They were 26’ canopies I made using the templates for the R-4 reserve. It was doing 12 ft/s at touchdown.

Sparky
My idea of a fair fight is clubbing baby seals

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theonlyski

... Rounds get you to the ground, are very reliable (when equipped with anti-inversion netting) ...



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Anti-inversion netting works great during military, static-line deployment, but is less-effective during straight-line, free-fall deployments.
The big problem with static-line deployment (from a C-130 airplane) is the relative wind hitting the skirt CROSS WIND as it deploys. The canopy still tries to partially invert, but the net prevents it from inflating on the other side of the skirt.

Another way to reduce the incidence of inversions is to spread the skirt earlier in the deployment process. You can spread the skirt with a spreader gun (widely used on zero-zero ejection seats), by inverting the apex or hanging an extra pilot chute in the middle of the skirt.
Inverting the apex and an extra pilot chute serve the same function by increasing spreading force at the skirt much earlier in the deployment sequence.
An extra pilot chute was first used on Irvin Canada's AIM canopy back during the 1980s, but the quicker inflation forced them to add the world's largest cat-eye apex, etc. to reduce opening shock.
By the end of the 1990s Manley Butler sewed the extra pilot-chute onto a slider to make his patented "Sombrero Slider." See videos of test-drops on Butler's HX series of round canopies installed in pilot emergency parachutes.

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Follow the logical sequence of concept design.

Start by defining the speeds of deployment (fastest airspeed and slowest airspeed).

Then define how heavy your load will be (zero-fuel weight and gross weight).

Then define how high you need to deploy (maximum cruise altitude and whether you can afford a zero-zero system).

Then define how many stages you will need (drogue?).

Then define maximum landing speed (save crew? save cargo? save entire airframe?)

Then size parachute canopies based on desired landing speed. Will it be cheaper to use medium-sized canopies, but depend upon braking rockets or air bags for the last stage of deceleration?

Then start detail design ...
Where should you attach your parachutes to the airframe?

Where can you stow parachutes inside the airframe?

How strong (tensile strength) does the fabric need to be?

How strong do the suspension lines need to be?

How strong do the risers need to be?

Then you start to define which type of material you need for each component. For example nylon may be the best for canopy fabric, but you might need Kevlar or steel risers to resist cutting by hot jet exhaust.

Once you have a rough out line of sizes and materials, review parachute volume and compare it with the volume available to stow it inside the airframe. Then do a rough analysis of the system weight.

You will find yourself looping back through many of these variables repeatedly.

In the end, your professor will probably not care whether your system is commercially viable, as long as you can prove a logical design sequence and accurate estimates of speed, weight, opening shock, volume, etc.

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Hi guys,
Just wanted to give a quick update just so you know I haven't ignored you all!
Just wanted to say a big thank you for all the information posted here, and the guidance, links, suggestions, and recommendations.
It has enabled me to progress on my project (one way or another) and I do believe I have enough info to carry it through to completion (again, one way or another).
So, again, thanks guys!

Kind regards,
Sam

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