Attaching the drogue parachute

[MetricRocketeer]

Hi everyone,

I would like to make sure that I understand how to correctly connect a drogue parachute.

I am planning to launch my Minie-Magg using a J-impulse motor. I have now purchased a Jolly Logic Chute Release, with which I intend to release my main parachute at a height of 300 metres above ground level. (That is as high as the JLCR will allow, and I don't think I should go lower. I would be glad to discuss that if anyone would like, but that is not the point of this question.) I also have a drogue parachute -- namely, a 15-inch Fruity Chute which I purchased from Apogee Components.

What I am asking about right now is where to place the drogue parachute.

Let's say that I were not using a drogue. Then the configuration along the shock cord would be the following: the airframe, the Nomex blanket wrapped around the JLCR-main parachute bundle, and then finally the nosecone. So far so good, right?

Using the drogue, however, I believe that this should be the configuration along the shock cord: the airframe, the Nomex blanket wrapped around the drogue and around the JLCR-main parachute bundle, and then finally the nosecone. I would connect the drogue directly to the shock cord, and this connection would occur between the Nomex blanket and the main parachute.

I am please asking my knowledgeable rocketry colleagues if they agree with this.

Thank you for your consideration.

Stanley

 

[Joe Rocket 97]

Normally a drogue isn't used with a chute release. I set my release at 100 meters

 

[MetricRocketeer]

Normally a drogue isn't used with a chute release.

Hi everyone,

First, Joe, thank you very much for your reply.

Second, do people agree with Joe? So as I understand what he says, if I am going to use the JLCR, then I shouldn't use the drogue. And If I am going to use the drogue, then I shouldn't release the JLCR.

Stanley

 

[DaHabes]

Hi everyone,

I would like to make sure that I understand how to correctly connect a drogue parachute.

I am planning to launch my Minie-Magg using a J-impulse motor. I have now purchased a Jolly Logic Chute Release, with which I intend to release my main parachute at a height of 300 metres above ground level. (That is as high as the JLCR will allow, and I don't think I should go lower. I would be glad to discuss that if anyone would like, but that is not the point of this question.) I also have a drogue parachute -- namely, a 15-inch Fruity Chute which I purchased from Apogee Components.

What I am asking about right now is where to place the drogue parachute.

Let's say that I were not using a drogue. Then the configuration along the shock cord would be the following: the airframe, the Nomex blanket wrapped around the JLCR-main parachute bundle, and then finally the nosecone. So far so good, right?

Using the drogue, however, I believe that this should be the configuration along the shock cord: the airframe, the Nomex blanket wrapped around the drogue and around the JLCR-main parachute bundle, and then finally the nosecone. I would connect the drogue directly to the shock cord, and this connection would occur between the Nomex blanket and the main parachute.

I am please asking my knowledgeable rocketry colleagues if they agree with this.

Thank you for your consideration.

Stanley

Others should weigh in, but I would be concerned that the main might tangle with the drouge if configured that way. As long as you NC isn't heavier than your airframe, you can go drouge-less. If you added nose weight and the NC is heavy, I would attach the drogue to the NC anchor with a 2-3x length of shock cord and it should have its own blanket. Keep it separate from the main and it's shock cord to avoid tangling.

 

[mikec]

What maximum altitude do you expect to reach? If it's low enough to recover on your flying field without the JLCR, then using it is just extra complexity.

I agree with Mike in general about the need for a drogue, but if you have a heavy nose cone you might consider attaching the drogue directly to the nose cone. There's a lot of conventional wisdom about attaching it 1/3 of the way down the main shock cord but personally I've found that's a recipe for tangling.

 

[MetricRocketeer]

Hi mikec,

I expect to go a little higher than 1000 metres.

Your are probably correct about adding unnecessary complexity. The thing is that I want the complexity just to experience using the JLCR. Using the JLCR is a simplified form of dual deployment, and I have never done any kind of dual deployment.

Stanley

 

[mikec]

I expect to go a little higher than 1000 metres... The thing is that I want the complexity just to experience using the JLCR.

That seems high for a Mini-Magg on a small J. I did my L2 on a 4" Madcow Super DX3 and went about that high.

Assuming this is your L2 flight (I think I saw that in other threads but perhaps I'm wrong, in which case ignore the following)

My advice, take it or leave it, is to keep your L2 flight as simple as possible and save the complexity for the future. But if you have a constrained field and/or it's windy, and you really go to the altitude you expect, then the JLCR could be useful.

 

[MetricRocketeer]

... I would attach the drogue to the NC anchor with a 2-3x length of shock cord ...

Hi Mike,

When you say 2-3x length, that is two to three times what, please?

Thank you.

Stanley

 

[MetricRocketeer]

That seems high for a Mini-Magg on a small J. I did my L2 on a 4" Madcow Super DX3 and went about that high.

Assuming this is your L2 flight (I think I saw that in other threads but perhaps I'm wrong, in which case ignore the following)

My advice, take it or leave it, is to keep your L2 flight as simple as possible and save the complexity for the future. But if you have a constrained field and/or it's windy, and you really go to the altitude you expect, then the JLCR could be useful.

Hi mikec,

I may do an L2 attempt -- you remember that correctly -- or I may just do some experimenting. I am yet not sure which one.

Stanley

 

[thzero]

Why not target 400-500' feet for the JLCR?

I wouldn't wrap the drogue chute with the main; use two blankets if you are going to wrap the drogue. Drogue attached to the nose cone (or upper stage) is usually where I put mine.

Using the drogue, however, I believe that this should be the configuration along the shock cord: the airframe, the Nomex blanket wrapped around the drogue and around the JLCR-main parachute bundle, and then finally the nosecone. I would connect the drogue directly to the shock cord, and this connection would occur between the Nomex blanket and the main parachute.

I agree with the other member... avoid unnecessary complexity on your level flights, other than what is required. If you don't have experience with a JLCR prior to your level 2, don't try it on the level 2.

Level1->Level2 should have lots of experience flying bigger rockets and if you are intersted in the JLCR then flying with it on smaller rockets (mid-to level 1 high) is a stepping stone.

e Nomex blanket and the main parachute.


Your are probably correct about adding unnecessary complexity. The thing is that I want the complexity just to experience using the JLCR. Using the JLCR is a simplified form of dual deployment, and I have never done any kind of dual deployment.

 

[MetricRocketeer]

Hi thzero,

Why not target 400-500' feet for the JLCR?

Here is what concerns me. The JLCR directions write on page 3: "Depending on how you fold your chute, it may take 50-125 feet below the release altitude to open and slow your rocket; keep that in mind as you select a release altitude."

So keeping this in mind, if I target as little as 400 feet, don't I risk going too low?

Drogue attached to the nose cone (or upper stage) is usually where I put mine.

OK. So how long should I make that shock cord be -- the one from the nosecone to the drogue?

Thank you.

Stanley

 

[AHansom]

Why not target 400-500' feet for the JLCR?

Because he's the Metric Rocketee!!!!

Go with your 100 meters and see what happens. Have fun.. Its just an experiment while fine tuning your combination..

I usually had my drogue on the nosecone/payload section or a couple feet back. Its about how your rocket reacts during the fall. A Minne Mag will fall completely different than a 3"x 72" rocket

 

[MetricRocketeer]

Hi AHansom,

Thank you for noticing that I am the MetricRocketeer!

OK. I will take your advice -- and the advice of all of you nice people -- into consideration.

Stanley

 

[thzero]

Because he's the Metric Rocketee!!!!

Go with your 100 meters and see what happens. Have fun.. Its just an experiment while fine tuning your combination..

I usually had my drogue on the nosecone/payload section or a couple feet back. Its about how your rocket reacts during the fall. A Minne Mag will fall completely different than a 3"x 72" rocket

[/QUOTE]

Depends on the size of your chute, etc. plus as mentioned the way the rocket is falling, etc.

 

[DaHabes]

Hi Mike,

When you say 2-3x length, that is two to three times what, please?

Thank you.

Stanley

Length of the rocket....

 

[DaHabes]

As for JLCR, I've never set mine lower than 400 feet. I've had the chute fully open as little as 100 feet above ground level when set at 400.

 

[teepot]

I don't use a drouge when I'm using a JLCR. The blanket and chute bundle act as the drouge. I would suggest that you Z fold your chute and Z fold the shroud lines. Then put the shroud lines between the folds of the chute. Roll it up tight. Make sure the band on the JLCR is tight. Then roll the bundle up in the blanket. A parachute folded this way inflates rapidly. I would replace the rubber band on the JLCR with a silicone band. I set my JLCR for 170 meters or lower depending on the wind.

 

[Ez2cDave]

Normally a drogue isn't used with a chute release. I set my release at 100 meters

It sounds like the OP may be using Motor Ejection to deploy the Drogue. He wants to deploy the Main, using the Jolly Logic release.

Dave F.

 

[Brian Ditmer]

I would think that the nomex blanket, along with the undeployed JL-chute, would provide a pretty good streamer-type slowdown that negates any need for a drogue chute.

 

[Powderman]

I was in the same boat as you about a year ago. I was researching drogue chutes and streamers to be used in conjunction with a JLCR as I was concerned with airspeed as the rocket was descending. With 20+ flights successfully under my belt on various airframes from 2.2" - 3.0" I can tell you I don't see any need for a drogue. The separated airframe coming down is in the 23-30fps range before the main opens. I have always had my JLCR set to open at 500ft and had great results with it.

I will tell you we put a modified Formula 75 up over 4000' and used a 65' Rocketman streamer as an added visual just so we could see it...it worked great.

 

[dr wogz]

Teddy from OneBadHawk & I had a good (but lengthy!) discussion about the use of drogues.

Its seems many use a drogue because they think they need to, not because they actually require one.

The basic premise of his comments are that the drogue will help a falling rocket maintain a certain attitude so that the main will blow out in a predictable manner. That it wont blow out with the rocket body point up or pointing down. That the separated rocket in this attitude, is enough of a drag to allow things to open & unfurl. The drogue is used to ensure you rocket is separated, but also that is it falling "flat" (the rocket parts are falling and their attitude is horizontal, or close to it..)



Now, a little chute attached to the end of the nosecone is a good idea, as it helps pull out the laundry should teh charge not be enough..

 

[billdz]

I have 3 chute releases and have flown them with several J motors. A few thoughts:
* Remember to turn it on (90% of fails are due to failure to turn on)
* The band must be tight around the chute
* The band goes around the chute, not around the nomex blanket (the blanket goes on top of the bundled chute)
* The ring that connects the pin to the band has a sharp end that can get stuck on the chute and prevent full opening. Wrap some tape around that end to avert this.
* I have almost always set the release height at 500 feet, except for a couple of windy days when I dropped it to 400. I have seen others successfully go as low as 300, but that's too low for me. I don't believe there is ever a need to go more than 700. I would say 300 meters (900 feet) is too high for a Minie-Magg on a J motor.
* Remember to turn it on.

 

[dr wogz]

And tether it!

• Tether it to the chute attachment point, not to a single chute shroud line (it can be lost / can slide up teh shroud line) I find the supplied tethers too short. I made some for myself, from Kevlar, in a few different lengths. You want absolutely no tension on the tether!
• Don't use a 'snap link'!
• use the right sized band for the chute!
• Practice folding the chute & attaching the JLCR. It is a bit of an art, but once you find 'your' method, should be fool-proof! the chute bundle should be fairly tight, but with no loose flaps or 'pockets' tuck in all in, like a nice burrito!
• Make sure the pin can & will release freely (don't bury this side 'in' the chute bundle!)

I have flown my numerous times, on numerous rockets, all set to 300'. 300 ft seems to be the standard at our club!

 

[Devin Batten]

My L2 was a 4" squat on a J450DM with a JLCR. Alt was about 1.5k meters. No drogue and contrary to other posters, release set to 60 meters. The winds were picking up and didnt want it to drift. Chute opened within 50ft of release using the mentioned "Z-fold". All in all Successful flight. I agree with the others on using it on other flights first. I built my confidence with it on a 29mm Big Daddy using G80s and a couple H's playing with the set release to see how my chute unfolded. Allowing me to have the confidence to set it so low for my L2.