Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

How would you create a plane-saving parachute?

Questions and Answers If you have general RC questions or answers discuss it here.

How would you create a plane-saving parachute?

Reply

Old 01-16-2003, 11:39 PM
  #1  
ajis
Junior Member
Thread Starter
 
Join Date: May 2002
Location: Wichita, KS,
Posts: 23
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

I would like to create a parachute system that attaches to the top of my Great Planes J-3 Cub. This is more for "see-if-I-can-do-it" than it is as a real model-saving system (although I see it doing so).

This would be a small box or contraption that straps to the top of the wing, with the parachute being a) able to safely carry the weight of a 1/4 scale cub to the earth; b) attach over the center of gravity; c) immediately propel the parachute outwards.

My idea would be to have a low profile closed-box system containing a folded parachute, servo, and a propellent to eject the parachute out of the box. The parachute would be ejected over the plane's C.G. The servo would initiate the propellent. The propellent would be something like a CO2 canister, etc.

If all went well, the plane could be in a stall, dive, or even inverted and the parachute would rapidly deploy. Then just cut throttle (if not already) and let the parachute take over.

Problems: Where do I get a parachute large enough to do this? How do I get a servo to fire the CO2 canister? Would a CO2 canister be too powerful, thereby causing damage?

I don't even know if I'll actually build it, but I enjoy the challenge of, in the least, trying to design it on paper.
ajis is offline  
Reply With Quote
Old 01-17-2003, 12:37 AM
  #2  
MHawker
Senior Member
My Feedback: (16)
 
MHawker's Avatar
 
Join Date: Mar 2002
Location: San Diego, CA
Posts: 2,586
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

I don't remember where I saw this, but it has already been done. My buddy and I talked about this some time ago and that's when I discovered it. Maybe it was from this forum.

Good luck with it anyway.

Mike
MHawker is offline  
Reply With Quote
Old 01-17-2003, 12:56 AM
  #3  
CP140
Senior Member
 
CP140's Avatar
 
Join Date: Jul 2002
Location: Vancouver, BC, CANADA
Posts: 801
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

I recall small rocket or hand-thrown(?) parachutes having been developed for ultralite and small general aviation use. Unfortunately I can't tell you much more than that. If you can track them down, you might get some info that would give you some ideas.....Also, I'm quite sure I've read a thread (as an aside, that IS the extent of my poetic ability!) on this(?) board with the same theme. I don't know how practical such a device would be for model use, but do agree that it's an interesting intelectual exercise.(Even if I can't spell/type!)

A couple of questions that will need quite firm estimates before proceding...What does your plane weigh and how fast would it be moving flat-out/stall?

Some ideas just off the top of my head.... feel free to shoot them down...

Adapt the pilot 'chute from a "real" parachute...any guess as to how big they are? Any riggers out there to lend a hand?

A spring to propel the chute from it's storage compartment?

A modified retract system(using compressed air of course)... (pretty bulky)... to pop the chute out...?

A model rocketry parachute deployment device to pop the chute?

Use a tent as a source for the parachute gores(Thank-you TLC and Junk-Yard Wars!)

OOOOOPS! Is that really the time?!?!?!?!?..... Gotta go!
CP140 is offline  
Reply With Quote
Old 01-17-2003, 01:09 AM
  #4  
CAPtain232
My Feedback: (40)
 
Join Date: Dec 2001
Location: Waynetown, IN
Posts: 2,476
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

As far as the size goes, get a weight that is as heavy as the plane and experiment.

Attachment point(s)...I think you will need more than one attachment point otherwise the plane will ROCK on the way down and may still cause major damage. It is unlikely that your (or anyone else's for that matter) plane is perfectly balance side to side.
CAPtain232 is offline  
Reply With Quote
Old 01-17-2003, 01:16 AM
  #5  
ajis
Junior Member
Thread Starter
 
Join Date: May 2002
Location: Wichita, KS,
Posts: 23
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

Originally posted by CP140
Some ideas just off the top of my head.... feel free to shoot them down...
Thanks for the ideas! A friend of mine flies ultralights, and a majority use a chemical propellent. However, the spring-loaded idea sounds good (probably the easiest to do!) As for a parachute, I'm sure I could explore around. I then could experiment (throwing things off my roof with different weights).

This is sounding more and more fun... And something I can do to kill away the winter months.
ajis is offline  
Reply With Quote
Old 01-17-2003, 02:50 AM
  #6  
Johng
My Feedback: (4)
 
Join Date: Jan 2002
Location: Deland, FL
Posts: 1,922
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

An uncle once gave me a vintage Popular Science hints & tips book from the '40's. It had plans for a model aircraft recovery chute made from tissue, I think. Don't know exactly where that book is right now...

The nylon tent idea is great. You can pick up a cheapo 2-man dome tent from Sports Authority for less than $20.

I have an old 28 foot diameter chute sitting in the corner. That's a lilttle big, I think.

I am a skydiver too, and pilot chutes are generaly probably too small - although they do make them with integral springs for students. Spring loaded is the way to go. Doesn't need to be much either.

Then again, you don't need to have a "soft" landing if the plane hits somewhat level and lands gear first, which you can plan for.

I would think a 6-8 foot diameter would be fine and pack to a size that would fit inside your shoe or smaller.

The triangular gores should not be cut so the natural shape of the canopy is flat, like pieces of a pie. One of the ways to build a round canopy is to build it as if it were going to be a cone. That is, if you were to take a round, flat surface and divide it into 30 gores, then take 27 of those same gores and build the parachute, That gives a cone that's a bit closer to the flying shape of the canopy. I'm not recommending any particular number of gores or anything though. Also, clip the very top to leave a hole. It stabilizes the canopy and reduces swinging.

You would probably want to shock mount the canopy to the plane as well, so a hard opening at high speed does not blow the plane apart.

One other thing would be to keep the chute inside the plane and actually separate the wing for recovery. wings flutter down, and the canopy would lower the rest safely. That would require a servo control for the wing to stay on. Yikes!

There was a commercial product like this only a few years ago. ..
Johng is offline  
Reply With Quote
Old 01-17-2003, 02:52 AM
  #7  
ilrcflyboy
Senior Member
My Feedback: (5)
 
Join Date: Oct 2002
Location: Bloomington, IL
Posts: 308
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

Wildcat fuels a few years ago had an airframe chute that they advertised on top of one of those airvistas. I was going through some older RCMs and found it. They, I don't believe, make it any more. I don't recal if they were the manufacturer or the distributor.
ilrcflyboy is offline  
Reply With Quote
Old 01-17-2003, 03:06 AM
  #8  
CP140
Senior Member
 
CP140's Avatar
 
Join Date: Jul 2002
Location: Vancouver, BC, CANADA
Posts: 801
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

I don't know that you'd be able to build a system that would prevent all damage upon landing... I think the best you could hope for was to turn a disasterous "crash about to happen" into a "..well it could have been a lot worse.."
CP140 is offline  
Reply With Quote
Old 01-17-2003, 04:10 PM
  #9  
banktoturn
Senior Member
 
Join Date: Aug 2002
Location: Bloomington, MN,
Posts: 762
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

ajis,

I might be inclined to have the chute come out a small hatch at the very tail end of the plane. It seems as though you would have more positive deployment, regardless of the attitude of the plane. Also, I would be inclined to use a smaller chute. You don't need to slow the descent too much to prevent damage, and I would be concerned about the thing drifting far away in a strong wind. I have seen planes take pretty hard slams on the spinner with no major damage. I would think that a small chute at the back would give almost the best possible angle of impact, since we don't need to worry about the little plastic pilot's health.

Good luck,

banktoturn
banktoturn is offline  
Reply With Quote
Old 01-17-2003, 09:27 PM
  #10  
Carlos Murphy
My Feedback: (72)
 
Join Date: Dec 2001
Location: Gardnerville, NV
Posts: 1,813
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Balistic Chutes

"ParaCat Recovery System" was the name of the unit that was made for R/C about 5 years ago but I can't remember who made it. One of the model mags did a artical on it.
I have one and have been looking for the instruction sheet (lost it) but I really don't think I need it. The system was designed to mount on top of a trainer using the same rubber bands that hold the wing on.
The system includes a beautiful main canopy and a drouge chute, both are round. They are stode in a heave, streamlined ABS container with a "flip" top that is released at the front by a servo. The airstream pulls the top up and back (it's hinged) and the drouge chute comes out pulling out the main chute which has a slider ring over the shroud lines to keep it from opening with a bang. I'm planning on using mine on a trainer of some kind just for fun, air shows and fun flys.
Carlos Murphy is offline  
Reply With Quote
Old 01-17-2003, 10:05 PM
  #11  
Johng
My Feedback: (4)
 
Join Date: Jan 2002
Location: Deland, FL
Posts: 1,922
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default ring

Yes, of course - a ring slider. you just put the ring on around all the lines and push it up right under the canopy when you are folding it. The smaller the ring, the longer it takes the chute to open. The ring should slide freely though.
Johng is offline  
Reply With Quote
Old 01-18-2003, 02:24 AM
  #12  
mulligan
Senior Member
 
mulligan's Avatar
 
Join Date: Apr 2002
Location: Sanford, FL
Posts: 1,147
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

You might not need propellent to deploy the chute- simply opening the container with the parachute stuffed inside it should allow it to quickly "drag" out and deploy naturally.

The "door" of the container might be linked to a servo which is in turn on an isolated channel that throws during fail-safe on a PCM (along with throttle kill and gear down).

- George
mulligan is offline  
Reply With Quote
Old 01-19-2003, 01:26 AM
  #13  
Ted Farmin
Member
 
Join Date: Mar 2002
Location: ID
Posts: 92
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

have the door open into the airstream like the old suicide car doors pivoting 180* and the airstream will pull the shut out.
Ted Farmin is offline  
Reply With Quote
Old 01-19-2003, 01:53 PM
  #14  
rcalfred
Senior Member
 
Join Date: Dec 2001
Location: Elk Grove Village, IL
Posts: 391
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default How would you create a plane-saving parachute?

Ajis: There was a how-to article on drag-chutes in the Jan/Feb issue of Flying Scale Models (page 10+) that could help in your quest. Email me your snail mail address and I will make a copy and send it to you. Regards.
rcalfred is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service