Chute Spool?

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neil_w

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It is an interesting concept - so simple! A fair number of uncontrolled variables but with some repeated flights you could fine-tune this close enough to keep the main chute deployment nice and low without too much risk of a crash. An ideal test vehicle would be BT-60 or bigger to keep the spool big enough to make building it easier, fairly light so when recovery is less than optimal the rocket has a chance of surviving. Worth pursuing I’d say...maybe some way to vary the speed of the streamer unrolling with a friction device...
 
I'd be nervous about adding friction for fear of having the thing jam. That said, the article does suggest rolling the chute so it touches the spool and adds friction that way.

I wonder how light the whole thing could be made?
 
Interesting idea. I have a chute release I use. I also put a mylar streamer and drouge in on top of the main. The streamer flashes in the sun light and helps find the rocket in the sky.
 
Just had a chance to look at it, it sure is interesting. It is like a more space efficient piston with the added benefit of slowed parachute deployment.

Clever idea.
 
Fellow Fox Valley Rocketeer member Mike Moran's been test flying various iterations of the Chute Spool for a couple years now. The article does a good job of explaining their design and construction. It would be a good use of your time to give it a shot, based on the flying I've seen Mike do.
 
It's an interesting, novel solution. The article stated that you get about 250 ft of streamer descent before the parachute opens. Unless this can be improved upon, I don't see the benefit of the added weight and complexity.
 
It's an interesting, novel solution. The article stated that you get about 250 ft of streamer descent before the parachute opens. Unless this can be improved upon, I don't see the benefit of the added weight and complexity.
I don’t think slightly more than half an ounce is much of a weight penalty, as for complexity...if it works reliably then the complexity is a moot point. I’m going to try it out and see what happens.
 
It appears the intent of the article is to simply reduce the length of the retrieval walk, and the possibility of a lost rocket that has drifted too far. And at a very low cost. The article also illustrates how 250' of free-fall will limit drift substantially on a rocket that flies 600'. That could be the difference between a successful retrieval and a rocket hung up in a tree. Itsays it's for low-power model rockets and is in its "infancy stage of development."
 
The article also suggests that if you build and use one, anything you experience and learn with it will be part of its development process. Kinda cool, actually.
 
Lengthening the streamer would delay the chute longer, as well, I'd think.
 
Yes, it would. However, it adds weight. Remember, the article mentions that the original design was too heavy and caused the rocket to be over-stable resulting in severe weather-cocking. I know 3 people in my NAR section that have flown with the Chute Spool (who also use the JLCR). I can sum up their observations in four points: 1. The calculated loss of altitude due to the extra weight was barely noticeable. 2. Drift and the retrieval walk are reduced (they measured the delay in seconds, not feet. The average was about 4 seconds after ejection, with three at 10, 12, and 15 seconds). 3. If your rocket is coming down ballistic (ie: by using too long of a delay) the Spool will open almost immediately due to the high velocity pulling on the streamer. 4. It's exciting watching it fall, anticipating when/if it will release the chute.😄
 
I actually have a fair video of it, but it says the file is too big to upload.
 
Thanks for posting this Neil.

Other than the streamer, which I like, isn't it basically the same concept as most rear ejection rockets, where the chute is located around the motor tube?



Red Columbine Dwg Sheet 9 of 10 Rev 02.jpg
 
I'm intrigued. Lower chute deploy and eliminating the need for ejection wadding make this a great idea for a lot of small, public flight areas.

I figure that any rocket design that can handle the wight and bulk of something like a baffle should be a possible contender.
 
Other than the streamer, which I like, isn't it basically the same concept as most rear ejection rockets, where the chute is located around the motor tube?
There are similarities, certainly.

However, a typical rear eject system is not designed to spool out the parachute progressively the way this one is. And the streamer wrapped around the parachute makes all the difference, as that is the "delay element" as it were.

I would guess that in most cases, it would be difficult to implement this in a rear eject because there isn't room between the motor and the body for all the extra streamer wrapping. In something like the Red Columbine, it could be possible, although I don't recall the body and motor mount dimensions.

The scheme in the Chute Spool of having an "axle" surrounded by a spinning sleeve would probably not be practical in a rear-eject, although I'm not 100% clear on why the same end couldn't be achieved by simply connecting the spool to the shock cord with a swivel. Would the Chute Spool design be more reliable? I assume there's good reason for having designed it the way it was, but I dunno. If just a swivel is adequate, you could definitely do this in a rear-eject model if you have sufficient space between the MMT and BT.

Finally: I'm a little curious about the streamer material that was used. What is that exactly? It looks thick and heavy.
 
.....Finally: I'm a little curious about the streamer material that was used. What is that exactly? It looks thick and heavy.

Certainly doesn't look like crepe paper... ;) Almost looks like 15# tar paper... like they use as an underlayment under roofing.
 
Thanks for posting this Neil.

Other than the streamer, which I like, isn't it basically the same concept as most rear ejection rockets, where the chute is located around the motor tube?



View attachment 433582

Going with that idea, you could possibly rig up a harness to allow the horizontal engine mount to rotate and be the spool for the chute and streamer, would actually be balanced if you have a 2 engine cluster and a straw/dowel in the middle, or use a little off center weight to balance a spent engine casing...just a rough idea here...

Screen Shot 2020-10-01 at 7.17.28 PM.png
 
Cover ribbon is 2.25 inch smooth polyester. It's the same stuff used to make bows and wrap gifts. It weighs .192 grams/inch. Same stuff for 0.875 delay ribbon (.090 grams/inch). No need for Nomex, chute protected by bulkhead and ribbons.
 
I'm going to give it a try! I just got back from Home Depot and got what I could. Have ordered the rest of the parts. The author of the Apogee newsletter made available a complete parts list. If you need it, let me know and I'll be happy to share. (By the way, the parts list includes 1.5" plastic chips. The only way I could buy them was in a bag of 250. I'll never use them all. If you want/need some, let me know.)
 
Apogee plywood coupler bulkheads also work very well. Part#'s 12258 and 12261 for the bt-55 and bt-60 applications, respectively. They come with a predrilled center mark.
 
I'm building a variation with a 'fat' core. With a Proton and battery inside. The core is 38mm motor mount and the piston is for 3" tubing. My plan is to run a pair of wires through the piston disk so that I can do my hot-wire cutter release on the chute - no guessing the release altitude.

My main goal is to reduce the length of the payload bay. I'm building a Pro Series II scale Nike Nike Smoke - and the scale payload bad is short. Pistons are a great way to reduce payload bay volume - this idea just puts the altimeter inside the piston.
 
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