Jolly Logic’s Chute Release and HPR

[John Beans]

Old info; Apogee updated their site.

 

[crossfire]

Here I thought john was going to announce the new Alt/CLCR device in time for X-mass. That's is what I asked Santa for.

 

[jahall4]

With a couple of "near" L2 flights under my belt I'm starting to answer my own questions about the JL CR. To date it has never failed to release the chute. I have had a 70" chute fail to inflate, but this flight of the same rocket using a 60" was picture perfect. I want to thank John for his help on this project: https://www.facebook.com/TheMarvinWrightRocket/posts/1242946265800375

 

[RocketPro]

I've used a JLCR on a 75mm minimum diameter rocket using an M1315 to 21,200 ft. I did not use a drogue, but just bound the main with the JLCR. Apogee deployment of the burrito and then 20,000 feet of drop. It worked great and based on the altimeter readings deployed at just the right altitude (1000'). Due to some fin misalignment, this rocket coned significantly but the JLCR worked flawlessly. Good product.

 

[BDB]

I've used a JLCR on a 75mm minimum diameter rocket using an M1315 to 21,200 ft. I did not use a drogue, but just bound the main with the JLCR. Apogee deployment of the burrito and then 20,000 feet of drop. It worked great and based on the altimeter readings deployed at just the right altitude (1000'). Due to some fin misalignment, this rocket coned significantly but the JLCR worked flawlessly. Good product.

Holy crap! Impressive!

 

[kevinkal]

Earlier this month while retrieving my rocket about 3/4 mile from launch, I heard a faint approaching rushing noise in the sky nearby... Before I could spot it, I heard a loud flapping/popping noise and then saw a separated airframe falling fast below a now failed main parachute. I later learned that the rocket was a 4" diameter fiberglass rocket that deployed the main with a JLCR at a 9,000+ ft apogee without using a drogue. Unfortunately, as the nosecone was heavy, the separated airframe and reefed chute came down too fast. When the chute release opened, the parachute failed due to excessive speed. The rocket survived the fall.. but the lesson learned here is to make sure that the separated airframe components and reefed chute don't fall too fast. A small drogue would have been appropriate in this case.

 

[jahall4]

When the chute release opened, the parachute failed due to excessive speed.

How do you know that? Was the chute damaged? I have experienced what I suspect was just the reverse that it did not inflate because it was falling to slow, but really that is just a guess.

 

[kevinkal]

When the chute release opened, the parachute failed due to excessive speed.

How do you know that? Was the chute damaged? I have experienced what I suspect was just the reverse that it did not inflate because it was falling to slow, but really that is just a guess.

I spoke with the owner of the rocket over dinner that evening and he both explained that the nosecone had a fair amount of lead in it, and likely helped pull the booster into a down pointing orientation allowing the system to fall too fast. I could see that the chute was failed after I heard the noise of it opening in the sky. The chute looked like a streamer after the failure, and the whole system fell quickly to the ground.. with enough drag to slow it down enough that the fiberglass airframe escaped damage. I had no idea what I had witnessed until speaking with the owner.

 

[jahall4]

...the noise of it opening in the sky.

So you think it opened, but so violently it became a streamer?

I have heard talk of flights where the rocket ended up in a ballistic type trajectory because the nose was so heavy that it became "stable" dragging the tail behind it. Far from that in my case where the nose and tail where hanging on the oversize drogue revolving around each other, but the main simply never inflated. Here is what it should have done...
https://www.facebook.com/TheMarvinWrightRocket/posts/1242946265800375

 

[grouch]

If you deploy the chute at excessive speed, something will break. Either the chute, airframe, shock cord or shock cord mount is going to meet their maker. This would not be a failure mode of the CR, it would be a flight profile failure. Wanna test it? Drive down the highway at 80/90 and stick your arm out the window while holding the bit of a 36" Fruity and report back.

 

[crossfire]

I fly a LOC Mini Magg with a fair amount of weight in the nose. 1st flight with the JLCR the nose was falling way a head of the booster. Some told me to put a drogue on the nose cone. I have a 15" drogue on the nose cone and I place the main chute Jolly package about 3' down from the nose cone. Has worked perfect for 5 flights now. MG fly's great on DMS H-550ST

 

[jahall4]

I fly a LOC Mini Magg with a fair amount of weight in the nose. 1st flight with the JLCR the nose was falling way a head of the booster. Some told me to put a drogue on the nose cone. I have a 15" drogue on the nose cone and I place the main chute Jolly package about 3' down from the nose cone. Has worked perfect for 5 flights now. MG fly's great on DMS H-550ST

Yep

 

[tim cubbedge]

I fly a LOC Mini Magg with a fair amount of weight in the nose.

How much weight did you add?

 

[crossfire]

Not really sure how much weight added. I can tell you with the weight the N/Cs weight is 1.75lbs It fly's very straight no matter what the motor is.

Gary

 

[Handeman]

Earlier this month while retrieving my rocket about 3/4 mile from launch, I heard a faint approaching rushing noise in the sky nearby... Before I could spot it, I heard a loud flapping/popping noise and then saw a separated airframe falling fast below a now failed main parachute. I later learned that the rocket was a 4" diameter fiberglass rocket that deployed the main with a JLCR at a 9,000+ ft apogee without using a drogue. Unfortunately, as the nosecone was heavy, the separated airframe and reefed chute came down too fast. When the chute release opened, the parachute failed due to excessive speed. The rocket survived the fall.. but the lesson learned here is to make sure that the separated airframe components and reefed chute don't fall too fast. A small drogue would have been appropriate in this case.

That's what I call a ballistic recovery. The rocket doesn't have to be together to come in ballistic like that.

I'm a little surprised it happened with a JLCR, but it's a fairly common happening with drogueless DD where the heavier payload and nosecone drag the booster section down ballistic. Most fliers get congratulated on a "good flight" when the main opens and everything comes down in one piece. I don't think most even realize how close to a failed recovery they got.

 

[dhkaiser]

I fly a LOC Mini Magg with a fair amount of weight in the nose. 1st flight with the JLCR the nose was falling way a head of the booster. Some told me to put a drogue on the nose cone. I have a 15" drogue on the nose cone and I place the main chute Jolly package about 3' down from the nose cone. Has worked perfect for 5 flights now. MG fly's great on DMS H-550ST

No concern with the NC falling into the main?

 

[crossfire]

I have never had a problem with main drogue set up

 

[RocketPro]

My 20K falling without drogue experience was with an 8 lb (with motor case & electronics) CF rocket. Note that I use 30 ft of paracord between the nose and fincan and the parachute bundle only a foot from the nose. In addition, my fincan is not stable by itself...this is important...so it tends to flat spin. Given this system, you don't have to worry much about the separated system getting into a streamlined configuration. My descent rate prior to deployment was about 100 ft/s just fine for a 48" fruity chute Iris with over the top shrouds. It did show some signs, despite my swivels, of spinning the cord a bit. YMMV!