Branching from my up-scale and two-stage tendencies, and building one to fly on an "E". Any advice? Minimum balsa fin thickness? Is there such a thing as "too light" for an "E"? Body tubes joined with coupler to achieve desired length, any thoughts on that?

I know I could probably dig some of this stuff up, and will if necessary, just thought I'd see if anyone on here had any thoughts.

Thanks in advance for any input.

It depends a lot on the E motor.

I have an old aerotech E50 that would rip a lightly built rocket up.

An Estes E9 is very "gentle" and do fine with the moderately built rocket, but the thrust is too light for some models that a D12 will "lob" nicely.

An Estes E12 is a nice step up from the D12. You can use it in *most* models that fly with a D12, although you'll likely need a little nose weight.

Did you have particular types of rocket in mind? If you're talking sport models, 1/8" balsa and standard Estes tubes will do just fine!

Through-the-wall fins are Good Thing with D and E models, especially if you want them around for flight after flight.

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NAR #27085 - Oregon Rocketry - SAM

Exactly the kind of things I needed to hear. I appreciate you taking the time to respond.

I used BT-60, and the rocket is about 34" I would say not having it next to me to measure right now. Based on what you said, the E12 sounds like a fit, and I will also take your advice with 1/8" balsa and through-the-wall fins. As far as style, it is just a personal creation probably closest resembling an AMRAAM style.

Thanks again for the help.

The unique thing about the Estes E motors is the extended burn time compared to C and D motors; 3 seconds of "up" for the E9 and 2.5 for the E12. But the "gentle" initial thrust spike of the E9 cannot be emphasized enough. For example, models that have a tendency to weathercock can go into full "cruise missile" mode in even moderate winds.

How about a picture of your scratch build ?

Thanks to you as well "samba". I'll be happy to put up pics when complete before painting and after painting. Right now its just a body tube with an engine mount and fin lines drawn on it and a nose cone.

No worries, I just like pictures . I'm guessing both motors will be fine in this puppy. Just watch the winds and don't build it too crazy heavy.

Through-the-wall fin mounting is not needed for any 'E' motor, even an E50.
Use EPOXY to bond fins and to fillet them to the tube.
Use at least 1/8" Balsa or better yet Basswood or Aircraft Plywood for the fins.
3/32" would be plenty if using Ply or Basswood.

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ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

Sounds a bit like this: http://www.estesrockets.com/rockets...07221-stm-012tm


Bill

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"Samb": I hear ya on the pics. Maybe when I get the fins cut I'll throw some up. Thanks again.

"ghrocketman": Thank you. Helpful info. Looks like I can go several routes.

"Bill": Well, that is pretty close, a little different fin shape that I was thinking of both top and bottom, but definitely the same style. I've had a bunch of tubes, cones, mounts, etc laying around just wanted to build one scratch, so I haven't even been looking at what's out there much. I do want to build a Dr. Zooch kit and a "Phoenix", but that's about all there is in my purchase queue right now.

Thanks guys.

I agree with gh, but (while I love epoxy) most good, wood glues would be up to the task as well.

Surface prep (sanding the area to be bonded with 120 grit sandpaper, followed by alcohol-on-paper towel to clean the surface) is your friend when you surface mount your fins.

Greg