Terrier chute idea..for TS and multi-stage designs

[Silverleaf]

Howdy,

As a scale nut, I've been mulling over a solution to the freefall Terrier booster problem over the last few months, and lack of a simple suggestion for safer recovery, outside of tumble, has kept me from building a scratch-built bird

So, though this idea isn't radical, or maybe its not even new, I think this will work for this and any two stage design.

The idea is to attach a kevlar shock cord to the Terrier section, and run it up and out normally, then attach a mylar sheet to the shock cord thats large enough to wrap around the folded and dusted parachute to protect it, then stuff it into a small dusted stuffer tube on the upper Sandhawk stage.

Thus at seperation, the chute is protected from ejection gases and upper stage flames, and should open normally.

Obviously, this needs to fit very loosely, so perhaps an end plug to keep it from falling out prematurely could be used.

Ideas, thoughts ?

Cheers,

 

[Silverleaf]

Sorry..had to switch the image format..

 

[Zippy]

Why do you need the mylar? Is it so the chute slides out easy?
There would be no ejection gases in the stuffer right? The chute would just be dragged out by stage seperation?

 

[Micromeister]

Silverleaf:
I guess my first question has to be, What scale are you working? please give the booster body tube size and stuffer tube sizes.
If I am understanding what the plan the booster chute is housed inside the upper stage? Is this in the space between the upperstage airframe and stuffer tube or directly under the motor?
To be honest I'm not following this at all, are you using some kind of upperstage elelctronic ignition? if so why not install the booster chute inside the booster between the airframe and stuffer, with an ejectable transition powered by a long delay motor 4 to 6 seconds, allowing the upperstage motor to ignite with your timer, mercury swithch or whatever, then after seperation the booster ejection deploys its chute in the usual way. This system works very well. the International US team has been using this technique on models down to 10mm sustainer Nike-Apaches in Scale Altitude for some time. Perfect-Flight has a postage stamp size time that will fit in a 10mm tube for about 10 bucks.
Hope this helps

 

[Silverleaf]

Ok,

Why do you need the mylar? Is it so the chute slides out easy?

Having done a pod-style attachment on the upper stage -attached to the lower stage in the same way - the chute was partially melted from the flame of the engine in past attempts.

Of course, I wrote this late last night, and didn't remember that many companies offer Mylar chutes now. *blush*

I've never used one before, always sticking with the Estes/Centuri plastic design. So I removed the mylar protector from the new gif image. lol

There would be no ejection gases in the stuffer right? The chute would just be dragged out by stage seperation?

The Chute would be dragged out by the seperation, and no there would not be ejection gases in the upper stage stuffer tube..


Scale:

This isn't going to be a large design, probably very close to the current Estes size - or a touch larger, so we're dealing with lower powered engines here - say - 2 C's or 2 D's total.

I might invest in a Aerotech D-in-a-C-case, but don't know if they have a booster motor/load available - and even so, thats an extra 60 bucks without fuel for just 2 engines.

Electronics:

I had been following the large Terrier-Sandhawk thread here, and saw that a few people were concerned about the Terrier booster returning safely. So this was a simple and a very low cost method to achieve that goal.

Personally, I've never used electronics in Estes designs and honestly think there is no need to spend extra money on a timer/ejection charge/battery combo for a simple Estes based design.

Besides adding unnecessary weight, there are the normal problems associated with electronics - Will the timer work, is the battery charged, did I attach the ejection charge/black powder properly..and if something does go wrong, there is the loss of the electronics - besides the rocket.

As to PerfectFlite's price, the current listing has one :

UT2A
microTimer2 digital staging/airstart/ejection timer
0.9"L x 0.7"W x 0.35"T
3.5 grams
$24.95

Nothing against timers and the like for higher power stuff mind you, but I've never used electronics, and though there are many companies out there that offer the products, I wouldn't know what to look for.

If I am understanding what the plan the booster chute is housed inside the upper stage? Is this in the space between the upperstage airframe and stuffer tube or directly under the motor?

As my gif image shows - the stuffer tube - about 10 inches in length sits IN the upper stage, and is beside the MM.

Many thanks for the feedback.8)

 

[Zippy]

Looking at it again, I think it's worth giving it a try. There's still a possibillity of the chute getting scorched on the way out though. Instead of your original mylar wrap how about an Estes wadding square?