My journey towards L3

[gbecker.kc6uvm]

I thought I'd start my own thread on my journey towards L3. About 4 to 5 months ago, I recertified at L2.

Hopefully, this is the right area of the forum to post my thread.

A month later, with assistance of another MDARS member, we came up with this design in Open Rocket:

IMHO, w/o considering the weight of the phenolic tubing with a fiberglass lamination and until the assemblies are built and weighed then entered into Open Rocket, these numbers are optimistic at best.

So, I took on a smaller, cheaper and lengthier journey towards a L3 certification with a dual deployment rocket:

My thought is to build smaller with cheaper launches and build up on the skills needed as this design of an upscale Citation Patriot with 29 mm motors. Building up with smaller dual deployment designs would increase my success when actually building and launching my L3 project as time and income will determine my success.



Since this design was made, the current project is longer at the first stage to accommodate a bigger drogue chute.

More to follow tomorrow....

 

[MarsLander]

Most LPR rocket designs can handle the larger span fins.

I would be concerned with flutter, given the span of the citation fins.

Lots to consider.

https://www.rocketryforum.com/threads/flutter-tools-for-you.183681/#post-2522850

 

[cls]

Besides flutter, landing a heavy HPR airframe on big fins will break them. There's good reasons most HPR has fins that do not extend below the aft end.

 

[loopy]

Besides flutter, landing a heavy HPR airframe on big fins will break them. There's good reasons most HPR has fins that do not extend below the aft end.

If properly reinforced, rear swept fins do just fine. I have a few HPR rockets with rear swept fins (including my L3 cert rocket), and they are holding up well. So, yes - it can be done, just needs proper care taken when building.

 

[gbecker.kc6uvm]

Presently, what is being designed is meant to keep my rockets within the scope of my L1 and L2 certifications to understand how the dual deployment rocket projects work. I took an inventory of what I have for parts in stock at home and designed rockets that can launch on a full range of 29mm, 38mm and 54mm motors. What's in stock (@home) are 3" diameter thin wall (Estes) and phenolic tubing in three inch and four inch diameters. I'm designing and building from scratch. The intent of this project is keep things as simple a possible (KISS) and get the L3 certification.



I traced a fin and input the data into OpenRocket as well as a tracing of Madcow DX3 fins below:


Fin flutter can be accommodated through changes and experimentation with new designs.

I've put aside the work of a 4" diameter rocket for a L3 certification until a second TAP advisor becomes available.

And lately, other commitments have keep me away from launches at MDARS and ROC.

The intent to build smaller, launch cheaper and learn from my mistakes. If something doesn't work or breaks up during or after launch, then it will be time to get back to the drawing board and the simulation software.

Thank you always for your constructive criticisms.