Need recommendations for fiber glass, dual-deploy L2 certification rocket

With those restrictions, you will be hard-pressed to find a 4" FG rocket that will stay under your waiver limits. I suggest you download Open Rocket (free) where you can lay in a design and simulate flights to see what you can use to keep your altitudes down. As far as motor tube goes, There is nothing wrong with using a bigger hole and an adapter, so that if you go to a field with a higher waiver you can let her rip.

Also, you can fabricate a removable dead weight to attach into your rocket to limit its altitude. You just have to make sure your impulse at launch is sufficient enough. I had to do that with my L3 attempt because I was flying on a field with a 9,000' waiver and my rocket was simming to 10,000'. I made a 5-lb. weight that attached to the threaded rods inside the AV bay, which brought the sim down to 8,000'. The rocket flew to 7,900'.

As far as kits go, I'd look at 5.5" kits like the Wildman Jart or Gizmo. The Gizmo is fun as heck to fly and it is rugged. Madcow has a 5.5" Nike Smoke and V-2 that are reasonably priced. With all of these, however you would need to either buy a DD add-on or get creative with a less conventional configuration. My 5.5" Gizmo separated normally with the nose cone and booster at apogee, but I should out the main with a chute cannon in the nose. It worked pretty well. These all have 54mm holes so you can either use a 2-grain 54mm J or use an adapter to fit in a 38mm J motor, which will be just as strong, but longer.

The nice thing about 54mm motor tubes is that depending on the size of your rocket, you can fly up to baby L motors, which can be flown with an L2 certification. 38mm motor tubes limit you to a nearly full J.

This is my Gizmo with a chute cannon main for DD. The launch is with a CTI K454 Skid. Flew to 4,400'. With a small J, it should stay well under 3,000'.

Rex R said:

sorry Jim no kit reccomedation here. I will however say that doing a dual deploy for the 1st time as part of a cert attempt is asking for trouble. I will however mention that Madcow is not the only fish in the pond.
Rex
*edit*
the rocket listed in my sig. isn't the same as the current version.

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10-4 I would get your feet wet on DD with L1 rockets...My first DD was using G64 and alot o fun. You want confidence with dual deploy before using it in a cert launch...unless your going with the JollyLogic chute release...you dont need much smarts to use it.lol

EeebeeE said:

With those restrictions, you will be hard-pressed to find a 4" FG rocket that will stay under your waiver limits.

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What? There have to be a dozen J motors that will stay under 3K in a 4" FG rocket.


And there are two K motors for 38mm

You could check out my hedgehog rocket. I could do an extended version for DD or a chute release work. I can make a custom one in 6" too. Lead time would be about a month though. The 6" one I can't do the 3d printed tailcone though. I could make you a fiberglass one, but that would be a bit extra.

https://binderdesign.com/store/page2.html. Nothing more to say.

good luck on the L2!!!

I must say that I really don't get why people are in such a hurry to spend major bux to learn that which can be learned for the equivalent of ice cream money.

Newbies don't yet realize it, but the learning curve in HPR is a BIG son-of-a-biscuit. That's why we have cert levels. Give everyone an opportunity to learn as they go.

Personally, my very first accelerometer-based dual-deployment flights were on F-52's. My first composite two stage flew an H238 to an F40, 100% success with dual-d in the sustainer. Cuz it wasn't my first flight using electronic deployment. And it didn't cost me a house payment.

Gee, do you mean I can learn to use electronics without spending $160 on a K motor? Jeepers, maybe I can get in several flights at a few launches using inexpensive motors, then when I do go for my dual-d L2 cert, I'll have experience and know what I'm doing, because I'm familiar with the possible failure modes, and have learned to mitigate those possible failure modes, to make my L2 cert 100%! (Not to mention that there will be a much higher possibility that I WON'T be dropping a chunk of hardware on someone's head.)

Or, there's the other option. One week after certing L1, I can drop $200 on a kit, another $500 on recovery gear and electronix, buy a $100 motor, and then I can roll the dice and pray that my lack of experience doesn't eventually come up snake-eyes and take out someone's SUV... Or their child.

cherokeej said:

I must say that I really don't get why people are in such a hurry to spend major bux to learn that which can be learned for the equivalent of ice cream money.

Newbies don't yet realize it, but the learning curve in HPR is a BIG son-of-a-biscuit. That's why we have cert levels. Give everyone an opportunity to learn as they go.

Personally, my very first accelerometer-based dual-deployment flights were on F-52's. My first composite two stage flew an H238 to an F40, 100% success with dual-d in the sustainer. Cuz it wasn't my first flight using electronic deployment. And it didn't cost me a house payment.

Gee, do you mean I can learn to use electronics without spending $160 on a K motor? Jeepers, maybe I can get in several flights at a few launches using inexpensive motors, then when I do go for my dual-d L2 cert, I'll have experience and know what I'm doing, because I'm familiar with the possible failure modes, and have learned to mitigate those possible failure modes, to make my L2 cert 100%! (Not to mention that there will be a much higher possibility that I WON'T be dropping a chunk of hardware on someone's head.)

Or, there's the other option. One week after certing L1, I can drop $200 on a kit, another $500 on recovery gear and electronix, buy a $100 motor, and then I can roll the dice and pray that my lack of experience doesn't eventually come up snake-eyes and take out someone's SUV... Or their child.

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Good points!

EeebeeE said:

With those restrictions, you will be hard-pressed to find a 4" FG rocket that will stay under your waiver limits.

Also, you can fabricate a removable dead weight to attach into your rocket to limit its altitude. You just have to make sure your impulse at launch is sufficient enough. I had to do that with my L3 attempt because I was flying on a field with a 9,000' waiver and my rocket was simming to 10,000'. I made a 5-lb. weight that attached to the threaded rods inside the AV bay, which brought the sim down to 8,000'. The rocket flew to 7,900'.

Click to expand...

Design and use a removable "Drag Plate" . . .

That way, you descent rate will not increase, possibly resulting in landing damage.

Dave F.

cherokeej said:

I must say that I really don't get why people are in such a hurry to spend major bux to learn that which can be learned for the equivalent of ice cream money.

Newbies don't yet realize it, but the learning curve in HPR is a BIG son-of-a-biscuit. That's why we have cert levels. Give everyone an opportunity to learn as they go.

Personally, my very first accelerometer-based dual-deployment flights were on F-52's. My first composite two stage flew an H238 to an F40, 100% success with dual-d in the sustainer. Cuz it wasn't my first flight using electronic deployment. And it didn't cost me a house payment.

Gee, do you mean I can learn to use electronics without spending $160 on a K motor? Jeepers, maybe I can get in several flights at a few launches using inexpensive motors, then when I do go for my dual-d L2 cert, I'll have experience and know what I'm doing, because I'm familiar with the possible failure modes, and have learned to mitigate those possible failure modes, to make my L2 cert 100%! (Not to mention that there will be a much higher possibility that I WON'T be dropping a chunk of hardware on someone's head.)

Or, there's the other option. One week after certing L1, I can drop $200 on a kit, another $500 on recovery gear and electronix, buy a $100 motor, and then I can roll the dice and pray that my lack of experience doesn't eventually come up snake-eyes and take out someone's SUV... Or their child.

Click to expand...

If you want to be even safer and more frugal, just fly Estes BP motors ( you can still fly "electronics" ) . . . All the same principles apply except, perhaps, supersonic flight.

Dave

I just bought a Mad Cow IQSY Tomahawk and I think that would be an excellent L2 kit. Standard wall FG airframe, molded color parts, 1/8" G10 fins. That rocket will be practically indestructive if you build it right. Use RocketPoxy and make strong internal fillets as well as external. You'd have to fabricate your own AV Bay, but it comes with coupler and a pair of coupler bulkheads, so it's just a matter of buying hardware from Home Depot and making your own sled. The first thing I do with any kit I buy is to weigh the parts and create an Open Rocket sim. It is attached, and includes different motor choices and a finished 3D look.