How low was your level 2 certification flight

[John_461]

AMW Der FiberMax. ~2300' on a J250SK

 

[KenECoyote]

~2,000 on a J landed nearby

 

[grouch]

7,360 some off feet for me.

 

[DrewW]

It turns out my goals for an engineering challenge (https://www.rocketryforum.com/threa...el-2-certification-flight.162931/post-2094578) at my L2 cert flight will in fact be challenging.

I've done a fair amount of simulations and searching for K motors in production, and found I will need to take some creative steps in order to meet my goals. The combination of available K motor thrusts/impulse make it hard to get a rocket on the order of 20-25 pounds off the rail fast enough yet also limit the expended energy.

I really want to do this for my L2, but it's seeming less certain with my other projects in work...oh and my actual job.

 

[Bob in Phoenix]

A Very interesting rocket. Was this a kit? Is it still available?
Thank you.
Bob in Phoenix
It came in at 14lbs. The J-415W is my go to motor for all of my 7.5" builds for low and loud flights that stay in the 2000' range. Great size and motor combo for a cert 2 attempt.

Here's the J-415W doing it's thing on a similar weight 7.5" CBU-97 Cluster Bomb:

View attachment 440537

 

[PSLimo]

Hi Bob,

It was a scratch build with dual deploy using a chute cannon.

Phil

 

[Tommie D]

I did mine level two back in 2001. A PML 1/4 Scale Patriot on a J350. No electronics just motor ejection. Landed about 100 feet from the pad. Perfect day that was at the Rocket Pasture.

 

[DrewW]

Hi Bob,

It was a scratch build with dual deploy using a chute cannon.

Phil

@PSLimo could you explain what a chute cannon is?

 

[FlyBy01]

Loc Goblin 2,800 ft. Motor ejection with chute release. I built it like a tank. J281SK in my profile picture, I maybe off on the motor nomenclature.

 

[Zeta]

~2,000 on a J landed nearby

Looks like a jet ! very cool

 

[PSLimo]

@PSLimo could you explain what a chute cannon is?

It's how you can have dual deploy in a single body tube. It's just a smaller tube inside the body tube that has the main in it with a separate ejection charge.

That method has been 100% reliable for me.

 

[prfesser]

My L2 was 20+ years ago. A scratchbuild like the PML Io but 4" diameter; lightweight, about five pounds. J350 with motor ejection, no altimeter on board but an old-fashioned program called wRASP said it should clear just about 3000 feet.

 

[ZEDL1]

Like Terry, my L2 flight was a long time ago. November 9,1996. It was at Three Oaks MI, as I lived in Toronto then and we had no HPR launches north of the border in those days. I flew a Dangerous Dave's (some will remember his kits) 4.1" fiberglass Mad Dog 40/40 using a K550W-L. Altitude was over 6,000'. Motor ejection only. The current amazing availability of electronics was in its infancy back then, but, and I don't want to mess things up for myself, I've never had a motor-only ejection failure.

 

[Philip Tiberius D.]

Stock built (wood glue) EZI-65 on a J275w with JLCR at 500’ hit 4181’

 

[SILVERFOX]

May 15, 2021 - MDRA - Madcow DX-3 Loki J-326 LR Apogee 3,200 feet with good DD

 

[TXJeff]

It's how you can have dual deploy in a single body tube. It's just a smaller tube inside the body tube that has the main in it with a separate ejection charge.

That method has been 100% reliable for me.


View attachment 521815

The chute cannon is fascinating!
So the engine ejects the drogue conventionally... and electronics fires the separate ejection charge up the cannon? Where are the electronics?

 

[JackC]

I used a Hawk Mountain 4 inch diameter, FWFG Jumanji on a Cesaroni J330 motor using a 54 to 38 adapter. Around 1,500 feet. Flight was way back in 2004.

 

[Glasspack]

My L2 flight was 2148' on the AT J315R in my Tyrannosaur.
Second flight was on a Pro54 K600 to 6400'.

Very cool Mike

 

[loopy]

LOC Expediter with the transition modified to be an altimeter bay for dual deployment. Flew it on a J500 for my cert flight on April 9, 2017. I think the altitude was just a bit over 4100'.

 

[PSLimo]

The chute cannon is fascinating!
So the engine ejects the drogue conventionally... and electronics fires the separate ejection charge up the cannon? Where are the electronics?

The electronics eject both the drogue and the main. I put the electronics in a hatch which is sealed off by the centering rings and the fins. Here's a pic of a 7.5" diameter with the electronics mounted to the hatch:




Here's a 5" Gizmo with the electronics mounted to a sled between the fins:

 

[Zeta]

It's how you can have dual deploy in a single body tube. It's just a smaller tube inside the body tube that has the main in it with a separate ejection charge.

That method has been 100% reliable for me.


View attachment 521815

I would love a few more details, does the main tube ride loose ?

 

[PSLimo]

I would love a few more details, does the main tube ride loose ?

The cannon tube needs an attachment point to the forward bulkhead along with the drogue shockcord and can be taped or velcroed to the main tube to keep it from moving around.

Simple way to add dual deploy to a stubby rocket that only has a single bodytube.

I've used them in every size rocket from a 5.5" Mini Magg to the 11.5" diameter scratch build below with the same type side hatch for the electronics.



Going back to the OP's original question. That rocket flew single deploy on a test flight and only reached 986' on a K-1100T, which would make a very low and loud level 2 cert flight you can view here:

 

[cbrarick]

7,360 some off feet for me.

you forgot to mention the 6 mile recovery walk. Being your wing man on that, I can vouch for the walk, getting back when it was dark!

 

[b.wieting]

The electronics eject both the drogue and the main. I put the electronics in a hatch which is sealed off by the centering rings and the fins. Here's a pic of a 7.5" diameter with the electronics mounted to the hatch:

View attachment 521976
View attachment 521977

Here's a 5" Gizmo with the electronics mounted to a sled between the fins:

View attachment 521979
View attachment 521978

Mounted to hatch—clever!!

 

[Zeta]

The electronics eject both the drogue and the main. I put the electronics in a hatch which is sealed off by the centering rings and the fins. Here's a pic of a 7.5" diameter with the electronics mounted to the hatch:

View attachment 521976
View attachment 521977

Here's a 5" Gizmo with the electronics mounted to a sled between the fins:

View attachment 521979
View attachment 521978

"Cut the red wire" !