Estes Skylab Saturn V kit: observations

[prfesser]

Opened the box to check off all the parts and read the instructions. The motor is recessed over 3" into the body tube. Why? Wild guess: to move the CG forward somewhat, perhaps? If it was even with the aft end of the BT they'd have to add even more nose weight for stability.

The box says an altitude of 200 feet with an E16, while OpenRocket says 487 feet. For the F15, 400 feet (box) vs. 752 feet (OR). I hope that difference isn't due to the Krushnic effect.

I'm going to move the MMT aft and add nose weight as needed. Will probably fly it on full F or even G motors anyway so the extra weight won't matter much. And the BT is pretty thin-walled so a few balsa gussets will be added between the MMT and the BT for strength. I'm toying with the idea of adding four more MMTs, 18 mm or maybe 24 mm.

It comes with eight chunks of clay---60 grams. Think I'll install a bolt and some washers for nose weight instead. Even more nose weight if I do a five-motor cluster.

Molded parts look very good indeed! I'll have to brush up on my attaching-styrene-wraps technique.

Overall it doesn't look as complicated to assemble as I thought it might be. Need to finish Big Bertha and clear off the workspace first.

Terry

 

[neil_w]

@hcmbanjo is just finishing up a build of this on his blog right now. https://modelrocketbuilding.blogspot.com/

 

[SecondRow]

The motor is recessed over 3" into the body tube. Why? Wild guess: to move the CG forward somewhat, perhaps?

That’s not so wild a guess. I’m pretty sure that is the reason. Krushnic’s not an issue because the mount is recessed less than the BT width, which is where I understand that the Krushnic effect comes into play.

I have the older model with the 24mm mount. I fly it on E15/20s and E30s regularly. No Krushnic issues from what I’ve observed. It’s a great flier.

When you fly it, be sure to follow the directions and keep it about 8” off the pad. Regardless of Krushnic, Bernoulli Lock is definitely an issue.

 

[James Duffy]

Nothing of significance to add, other than to note that "The Krushnic-Bernoulli Lock" would be an awesome band name.

 

[kuririn]

Opened the box to check off all the parts and read the instructions. The motor is recessed over 3" into the body tube. Why? Wild guess: to move the CG forward somewhat, perhaps?

Also to provide enough room for the display nozzle coupler to slide in.

 

[lakeroadster]

Any updates on this rocket?

 

[Pappy]

gus·set
/ˈɡəsət/

noun
noun: gusset; plural noun: gussets

a piece of material sewn into a garment to strengthen or enlarge a part of it, such as the collar of a shirt or the crotch of an undergarment.

a bracket strengthening an angle of a structure.

@prfesser i did not know that. thank you for the education