Estes rocket cover sheet: estimated weight---- with or without engines?

[BABAR]

Okay, so finishing up my Estes MIRV.
I am at 4.6 oz or about 132 grams. WITHOUT ENGINES
I am at 6.25 oz or about 172 grams with a quest C-6 (wrapper removed) and 3 A10-3ts.

The little card on the cover that comes on the rocket lists
Estimated Weight: 4.7 oz (134 g)

Is that weight listed on the package supposed to be with or without the engines?

When I go to the Estes engine chart for Estes C6-0 (and I was planning on using a Quest, since I bought a whole bunch of them mainly because they came with the quest igniters which are hard to get)
https://www2.estesrockets.com/pdf/Estes_Engine_Chart.pdf
Lists 4.0 oz or 113 grams as max lift of weight for C6-0, C6-3, C6-5
(interesting as even if package weight is WITH engines the listed package weight is still over what the C engine recommended max lift off weight is)

Any ideas?

Thanks

 

[EXPjawa]

I'm pretty sure that the official weights are sort of idealized without motor(s). Weight with motor would depend on what motor you chose, so it'd be a bit of a variable. As such, I think that the numbers are for something of minimal build situations (going easy on the glue & paint).

 

[neil_w]

I'd assume they just weigh their prototypes, and would guess that they generally build light, but not crazily so.

 

[Rex R]

I once weighed all the parts as they were supplied, the fins still in their matrix and the total weight matched the card/catalog weight. it is possible to build lighter...but not likely . that said there is a bit of wiggle room in the max liftoff weight. for the mirv I would expect it to stage kind of low (which makes booster recovery easier). you will want a full 36" launch rod though.
Rex

 

[dhbarr]

My Big Daddy says five and change on the cover, but is actually seven plus in parts.

Bigger NC & bigger fins = more variation. BTs are fairly consistent, as are chutes etc.

 

[ayryq]

Not exactly answering your question but I build pretty heavy (extra long center rod, added streamers) and my MIRV flew fine this weekend with a B6 for the booster.
[video=youtube;2tlsOAMtVoE]https://www.youtube.com/watch?v=2tlsOAMtVoE[/video]
Edit: Mine was 6.5 oz with engines. It staged pretty low as you can see, but that's what you want isn't it? Both times I've flown it I've found the booster nearly on top of the launch pad.

 

[BABAR]

Not exactly answering your question but I build pretty heavy (extra long center rod, added streamers) and my MIRV flew fine this weekend with a B6 for the booster.
[video=youtube;2tlsOAMtVoE]https://www.youtube.com/watch?v=2tlsOAMtVoE[/video]
Edit: Mine was 6.5 oz with engines. It staged pretty low as you can see, but that's what you want isn't it? Both times I've flown it I've found the booster nearly on top of the launch pad.

THANX!
Very helpful
Extra long center rod? If I read you correct, we think alike. I have extended the center rod to nearly the length of the sustainer tubes. I also moved the internal launch lugs as far forward as possible.
I think I may get some Estes c6-0 s rather than the QUEST. Looking at Rocket Reviews engine data, looks like a little more net oooomph from Estes

 

[gna]

I once weighed all the parts as they were supplied, the fins still in their matrix and the total weight matched the card/catalog weight. it is possible to build lighter...but not likely . that said there is a bit of wiggle room in the max liftoff weight. for the mirv I would expect it to stage kind of low (which makes booster recovery easier). you will want a full 36" launch rod though.
Rex

My Big Daddy says five and change on the cover, but is actually seven plus in parts.

Bigger NC & bigger fins = more variation. BTs are fairly consistent, as are chutes etc.

Well, I feel better now. All of my low power kits (Estes, Semroc, Custom Rockets) have been heavier than the instructions say, and several of my scratchbuilds are heavier than OR says.

 

[ayryq]

THANX!
Very helpful
Extra long center rod? If I read you correct, we think alike. I have extended the center rod to nearly the length of the sustainer tubes. I also moved the internal launch lugs as far forward as possible.
I think I may get some Estes c6-0 s rather than the QUEST. Looking at Rocket Reviews engine data, looks like a little more net oooomph from Estes

I did a build over at Rocket Reviews: https://www.rocketreviews.com/estes-mirv-1127.html
I initially made the center rod too long; you need at least a launch-lug-length between the end of the rod and nose cones to make putting it together easier.

 

[EXPjawa]

and several of my scratchbuilds are heavier than OR says.

If you're coming out heavier than OR is predicting, you aren't adding enough mass for glue and paint into your sim...

 

[BABAR]

I did a build over at Rocket Reviews: https://www.rocketreviews.com/estes-mirv-1127.html
I initially made the center rod too long; you need at least a launch-lug-length between the end of the rod and nose cones to make putting it together easier.

Ahh, that was YOU! I didn't make the link between your TRF and RocketryReview. Personas.
Nice review. I have been taking pics as I go and hope to congeal them into something helpful later.

 

[gna]

If you're coming out heavier than OR is predicting, you aren't adding enough mass for glue and paint into your sim...

Finishing/paint is a choice I see, but not glue. But I have weighed parts before I built and they weigh more than OR thinks, so I have to override. I usually have to adjust weight after I'm done.

 

[EXPjawa]

Admittedly, I'm using Rocksim rather than OR. The predicted masses are usually close, but there's a bit of variation in the densities of materials from wood to wood, etc. When I want to make an accurate model, I do weigh the parts and make adjustments is the model accordingly. I try to do it playing with thicknesses so that the CG isn't overridden (by simply plugging in the mass), especially for cones. So, with that, the total mass of the actual components is accurate. I usually add glue and paint as a mass object, based on how much I've used in the past for that sized rocket. If you do all that correctly, you should be able to trim the glue/paint mass and location and fairly accurately reproduce the real rocket's mass and CG.