Custom Mini Christmas tree rocket build

[Daddyisabar]

Lol, there was a word replacement in my previously reply which my immature sense of humor thought would be appreciated . Probably would only apply to flying REAL trees AFTER Christmas, which nobody should do anyway.

with all due respect to those who subscribe to the “In Thrust We Trust”, with the exception of tractor motors, since I started scratch building I have always been dubious about solving every problem with added nose weight and added thrust.

you add nose weight and definitely makes it more stable by pulling CG forward

but if the added nose weight precludes you from get a draggy OddRoc off the rod or rail with sufficient velocity, you have to add more motors in the tail, which brings the CG backward

so you add MORE nose weight……but then……

you can see how this may end up both literally and figuratively having your rocket design chasing its tail.

my go to solution for instability has usually been to increase the tail feathers AND the thrust. Agreed the added fin surface area does have a cost in both weight and drag, but particularly for rockets that start with a far forward CP, it seems more efficient than just throwing in more nose weight.

Oh the tribulations of silly oddrocs, forces you to think backwards, outside the box. Heck, just throw the box away.

I would always tell our old RSO that power and nose weight solved 90% of my oddrocs problems and THAT ain't bad. He replied that the other 10% of the problems were far too serious and to go launch it in South Park.

Be kind to the crabby old dudes this Christmas, they are just trying to keep you safe and sound. SINGING: CAPITAL CITIES SAFE AND SOUND.

 

[BABAR]

I would always tell our old RSO that power and nose weight solved 90% of my oddrocs problems and THAT ain't bad.

I bow to the Jedi Master.

 

[Daddyisabar]

I bow to the Jedi Master.

The RSO was the Master. I was but an ungrateful youngling headed on a road trip to launch.

 

[BABAR]

I was surprised it did imo poorly considering they had launched one last year. I feel the rear fins are too large which probably had the cg too far back. They should've tried a swing test!

i didn’t watch that closely for what the fins were made of. Agree bigger fins add more mass (and drag), so they DO pull CG back, but they also change CP. In this rocket, I think most of the fin area in her rocket is directly behind the tree boughs, so not a lot of smooth flow to become effective. Monday morning (post Christmas) quartbacking, but adding box fins to the edges of the “X” fin profile here would have massively increased effective surface area (at least they would be further outside the predominantly blocked current fins), depending on construction material would not necessarily change CG that much, would have made a stronger ”tree stand”, WITHOUT really changing the basal diameter.

i think an outer box or ring fin would be the ideal fin for a Christmas tree rocket . Ring fin would be a bit hard to make, although there are some excellent master “wood benders” here (@Rktman , @neil_w , and @lakeroadster come to mind). Box fin would be pretty easy, although less efficient, you’d probably want to make the central brace/attachment fins with a longer hemi-span to keep the box well outside the air wash of the tree. Papering with Christmas wrapping paper would be the icing on the cake, add strength, decor, with little weight penalty.




https://www.rocketryforum.com/threads/hiding-your-fins-in-plain-sight-240-calories-of-fun.47954/

 

[CoolRockets]

I had this idea a while ago, cool that you actually made it