L2 low altitude rocket

[ThirstyBarbarian]

I flew a Warlock for my L2. It went to around 2,000’ on a CTI J290. The Doorknob is another great L2 rocket. It’s basically a longer version of the Warlock and will stay lower on the same motor.

Another thing that I and a few of my rocket buddies have done for lofting payloads is to make a removable payload section or even just a tube extension for our Warlocks. It can be as simple as a length of body tube and length of coupler. That can extend the warlock so you are getting in the range of the 10:1 fineness ratio, if you are concerned about that. It also adds a bit of drag, and can bring your stability margins more into line with the rule of thumb 1 caliber.

A typical extension might be a 15” piece of tube and 15” coupler. Glue them together with 7.5” of coupler sticking out the tube extension. When you want the longer rocket, just add the extension. You can simply tape it in place, or most likely friction would hold it. Remember to boost your ejection charge — it about doubles the volume you need to pressurize.

 

[ThirstyBarbarian]

ok, i can increase drag on my rocket and maybe add enough mass to not cause coasting distance to be affected.
maybe i can add something to my LOC IV fins to cause some drag haha or to the BT

I would recommend not modifying your LOC IV for L2. It’s not the right rocket for the flight you are trying to do. Start off fresh with a 5.5” to 7.5” kit (probably 7.5”) that is made for L2 motors and low flights.

 

[techrat]

maybe i can add something to my LOC IV fins to cause some drag haha or to the BT

Ways to increase drag on the fins:
#1) Cut holes in the fins
#2) Add "Feet" or landing pads to the fins
#3) Add right angle "Square" (see Estes Photon Disruptor) fins to the fins
#4) Add "streamers" to the outside of the rocket (attached to the fins)

 

[AlexBruccoleri]

As a reference point. I recently built a LOC I-ROC and used their modular nose weight system to add roughly a pound of weight. I flew it on an I284 to 1500 feet. A baby J such as a J270 would not go much higher. It is a nice rocket, a trivial build and a fun flier in fields with low waivers.

 

[MidOH]

A 5.5" Loc Goblin is my choice for this.

Kept as light as possible. Add a ply tracker bay to the nose cone.

 

[tsmith1315]

maybe i can add something to my LOC IV fins to cause some drag haha or to the BT

I really dig the shag carpet treatment suggested by @BDB but keeping a LOC IV under 2k sounds like a project for a different time. I must agree that a larger diameter airframe is the best route. A rough or fuzzy finish will only help.

Check out this adjustable drag design that @Rocketjunkie has been working on, for a lesson on how drag can affect altitude:

https://www.rocketryforum.com/threads/variable-drag-project.157027/

 

[techrat]

I've got it! I've figured it out. You just have to get your LOC IV really, really depressed. Then it will say "life is a drag".

 

[Lt72884]

I've got it! I've figured it out. You just have to get your LOC IV really, really depressed. Then it will say "life is a drag".

I like this idea. thanks for the input. I used to have alot of chemistry jokes myself, but all of them argon..

 

[Lt72884]

I really dig the shag carpet treatment suggested by @BDB but keeping a LOC IV under 2k sounds like a project for a different time. I must agree that a larger diameter airframe is the best route. A rough or fuzzy finish will only help.

Check out this adjustable drag design that @Rocketjunkie has been working on, for a lesson on how drag can affect altitude:

https://www.rocketryforum.com/threads/variable-drag-project.157027/

I was actually thinking of putting carpet on my fins haha.
Im thinking a lvl 2 kit such as the warloc or gizmo xl will be the option. This is just to get us certified to lvl 2 so we can then build our actual capstone rocket

 

[gdjsky01]

It won't help now, but I did my L2 on a 4 inch Public Enemy Gladiator with about 2kg of lead in the nose and J275. Motor eject. It was an easy peasy to watch flight.

 

[JackC]

I was actually thinking of putting carpet on my fins haha.
Im thinking a lvl 2 kit such as the warloc or gizmo xl will be the option. This is just to get us certified to lvl 2 so we can then build our actual capstone rocket

One way to keep it low and super stable is to adapt the rocket into a ring fin rocket. Basically, if the rocket is a 3 inch diameter rocket, make the ring a 7.5 inch body tube that is 3 inches long and use your fins tips to attach to the ring. To see an example of this, do a Google search on “emrr Galadriel”.

 

[techrat]

One way to keep it low and super stable is to adapt the rocket into a ring fin rocket. Basically, if the rocket is a 3 inch diameter rocket, make the ring a 7.5 inch body tube that is 3 inches long and use your fins tips to attach to the ring. To see an example of this, do a Google search on “emrr Galadriel”.

That's what I was forgetting in my list of ways to add drag to the fins. Thanks!! Yes, making a Ring Fin will add a ton of drag to the rocket.

BTW: I have another idea to add drag, and a ton of it, guaranteeing a low and slow flight -- don't use paint.

Instead, spray on that "Rubberized Undercoating" they sell at automotive stores. It sprays on like paint, but will make the rocket all lumpy instead of smooth. It will also look ugly, but it will be practically indestructible as well. But all those lumps will make for a draggeriffic finish that will keep you under 2000 feet no matter what motor you fly.

 

[tsmith1315]

Instead, spray on that "Rubberized Undercoating" they sell at automotive stores.

Many ideas here!

I like the ring fin, because of my first rocket, the Astron Sprite.

As for surface treatment, another idea is to use flocking. Spray it with Super 77, sprinkle with flocking, and you have a luxurious velour-textured spaceship. Soft and fuzzy!

My granddaughter would love it, maybe that's another one to put in the build pile. It would have to be purple...

https://www.flockingunlimited.com/collections/rayon-flocking

 

[Lt72884]

That's what I was forgetting in my list of ways to add drag to the fins. Thanks!! Yes, making a Ring Fin will add a ton of drag to the rocket.

BTW: I have another idea to add drag, and a ton of it, guaranteeing a low and slow flight -- don't use paint.

Instead, spray on that "Rubberized Undercoating" they sell at automotive stores. It sprays on like paint, but will make the rocket all lumpy instead of smooth. It will also look ugly, but it will be practically indestructible as well. But all those lumps will make for a draggeriffic finish that will keep you under 2000 feet no matter what motor you fly.

Oh yeah, that plastadip stuff is great. I was hoping this would cause enough drag. If done correctly, it would look pretty cool too.

 

[Lt72884]

One way to keep it low and super stable is to adapt the rocket into a ring fin rocket. Basically, if the rocket is a 3 inch diameter rocket, make the ring a 7.5 inch body tube that is 3 inches long and use your fins tips to attach to the ring. To see an example of this, do a Google search on “emrr Galadriel”.

Thats a nice design feature. Maybe ill add that to the LOC IV for my lvl 2 or buy a lvl 2 kit and add that to it. thanks

 

[JackC]

That's what I was forgetting in my list of ways to add drag to the fins. Thanks!! Yes, making a Ring Fin will add a ton of drag to the rocket.

BTW: I have another idea to add drag, and a ton of it, guaranteeing a low and slow flight -- don't use paint.

Instead, spray on that "Rubberized Undercoating" they sell at automotive stores. It sprays on like paint, but will make the rocket all lumpy instead of smooth. It will also look ugly, but it will be practically indestructible as well. But all those lumps will make for a draggeriffic finish that will keep you under 2000 feet no matter what motor you fly.

That’s true! I used it to paint the inside of one of those truck bed tool chests to creat a non-sparking surface for a motor storage box. You must have seen the Mythbuster episode where that stuff practically made a building indestructible.

 

[techrat]

That’s true! I used it to paint the inside of one of those truck bed tool chests to creat a non-sparking surface for a motor storage box. You must have seen the Mythbuster episode where that stuff practically made a building indestructible.

Yeah, I've used Herculiner and other rubber coatings to save a lot of old VW Beetles. If you prep the surface properly so it sticks well, it really creates a tough coating that saves a lot of wear and tear. And yes, Mythbusters did a test of "Rhinolining" to make a cinderblock structure somewhat bomb-proof. It's amazing stuff.

 

[SDramstad]

Just remember 1 thing about ring fins. They will not survive the transonic range. Fly it too fast and you will shred the ring.

 

[techrat]

Just remember 1 think about ring fins. They will not survive the transonic range. Fly it too fast and you will shred the ring.

I think an L2 LOC IV isn't going to go supersonic, or even close to it. The design is too fat, and the fins are too wide. But that's just my opinion.... The OP is aiming for "low and slow", so I doubt he's going for Thrusty McThrustface.

 

[SDramstad]

I think an L2 LOC IV isn't going to go supersonic, or even close to it. The design is too fat, and the fins are too wide. But that's just my opinion.... The OP is aiming for "low and slow", so I doubt he's going for Thrusty McThrustface.

Yup. But sooner or later he will put something bigger in it. Just because......

 

[techrat]

Yup. But sooner or later he will put something bigger in it. Just because......

Yep, I agree. But that'll be an interesting flight.

 

[Off Grid Gecko]

Just wondering, would a ring fin be appropriate for a cert flight, or does that fall under "non-standard" designs?

 

[JackC]

Just wondering, would a ring fin be appropriate for a cert flight, or does that fall under "non-standard" designs?

It would NOT fall under a non-standard design! Non-standard would be spools or saucers.

 

[MidOH]

If you want to fly level 2 rockets, just fly a level 2 rocket.

There's no point in gaming the system, with a rocket that'll only fly once.

 

[Hobie1dog]

If you want to fly level 2 rockets, just fly a level 2 rocket.

There's no point in gaming the system, with a rocket that'll only fly once.

+1 .......end of discussion.

 

[DaHabes]

I used my LOC Minie Magg for my L2 with a chute release. 3,200 feet on a J270W. Easy peasey.

 

[jmasterj]

It falls under a non-standard design.

Really? Tube fins are allowed, why is a ring fin any less normal than that?

 

[DaHabes]

Really? Tube fins are allowed, why is a ring fin any less normal than that?

Tube fins will survive transonic, ring fins won't. At what length does a ring become a tube? Not sure, but I suspect it's when the length of the tube fin exceeds the diameter of the tube.

 

[techrat]

This is confusing -- So you are saying that if I have a 5" diameter body tube and I use three 6" tube fins, that's not allowed, because they are now ring fins rather than tube fins? Holy cow.

 

[DaHabes]

This is confusing -- So you are saying that if I have a 5" diameter body tube and I use three 6" tube fins, that's not allowed, because they are now ring fins rather than tube fins? Holy cow.

What is the definition of a "ring"? A circular band. What is the definition of a "tube". A long hollow cylinder. Length to diameter is the defining difference.