Aerobee conduit cross section shape?

[SolarYellow]

I've been looking at Aerobees lately. I have ROTW, and the conduits are called out as 1.9" wide and either 1.25 or 1.30 high. My question is about the actual contour.

Are they elliptical in cross section? Is it a simple 0.95" radius half-circle elevated off the airframe 0.30 or 0.35 inches with straight sides? Is it some other shape?

Haven't been able to find information that would make me confident on this.

I'm thinking about 3D resin printing them to get the size and shape right, rather than spending forever trying to sand rectangular stock to the right dimensions and form and getting three or four different parts that don't match each other and are even inconsistent along their lengths, or living with something that's vaguely suggestive of the shape so everyone will know what I mean, even if it's not right.

 

[tsmith1315]

Is it a simple 0.95" radius half-circle elevated off the airframe 0.30 or 0.35 inches with straight sides?

Pretty close to that cross section. Which Aerobee?

 

[kuririn]

Take a look at the "Top View" of each Aerobee.
It shows the contour of the conduits lined up with the fins.

 

[SolarYellow]

Looking at Aerobee-Hi, NRL-41 & 42. But in digging around for this, I learned about the cute little 100 and might need to build one of those, too. I imagine they are all relatively similar, although I did find a photo that shows a row of clips along the motor tube that obviously hold the conduit on. My conclusion is that they were a pretty simple sheet metal part, and thus could have been fabricated with a variety of shapes.

The display model photo of the 100 looks like it might be a smaller radius on the outside than a half-width, and then straight/flat sides for maybe 2/3 of the height, angling outward toward the airframe.

 

[tsmith1315]

This is the 100:

 

[tsmith1315]

 

[SolarYellow]

Awesome! That's exactly what I was looking for.

Short of making up some forming rollers on a lathe, I think 3D printing is the right way to make those. A person could spend a very long time trying to sand square stock into that cross section and not come close.

 

[tsmith1315]

Be careful, you can drive yourself crazy over stuff like this!

 

[SolarYellow]

Can? It's what I do.

 

[tsmith1315]

Can? It's what I do.

I’m in analysis paralysis over a few Aerobee models I’m working on.

I dug a long time for a little info like this to answer questions, and now don’t know when to say enough is enough.

 

[bjphoenix]

I'm thinking about 3D resin printing them to get the size and shape right, rather than spending forever trying to sand rectangular stock to the right dimensions and form and getting three or four different parts that don't match each other and are even inconsistent along their lengths, or living with something that's vaguely suggestive of the shape so everyone will know what I mean, even if it's not right.

I built an Aerobee-Hi from an Estes HiFlier XL kit, photos in the thread below. I wasn't trying for perfect scale, I made everything from parts in the original kit, so I made the conduits from the scraps of 1/8" balsa. I sanded them with a sanding block so the shape surfaces would be straight along the length of the rocket. It really wasn't that hard. I put some wood filler on spots and sanded with the sanding block, and a couple of coats of primer then sanding.

https://www.rocketryforum.com/threads/aerobee-hi-kit-bash.171446/

 

[tsmith1315]

Short of making up some forming rollers on a lathe, I think 3D printing is the right way to make those. A person could spend a very long time trying to sand square stock into that cross section and not come close.

That’s probably best. I’m still thinking over a couple methods to try. Printing would be way easier.

 

[SolarYellow]

I built an Aerobee-Hi from an Estes HiFlier XL kit, photos in the thread below. I wasn't trying for perfect scale, I made everything from parts in the original kit, so I made the conduits from the scraps of 1/8" balsa. I sanded them with a sanding block so the shape surfaces would be straight along the length of the rocket. It really wasn't that hard. I put some wood filler on spots and sanded with the sanding block, and a couple of coats of primer then sanding.

https://www.rocketryforum.com/threads/aerobee-hi-kit-bash.171446/

I saw your thread and like it. Now am thinking about doing one that size, too. I'm about to place an order that includes the NC-60 pack, which is one each of the cones from Sprint XL, ESAM-58, and Hi-Flier XL. Current placeholder plan I've been mulling over on my walk for the past hour or so, thanks to you, is a sport-scale NRL-42 and use the other NC as a better boat tail to pair with the Sprint elliptical.

Plus, your build lends support to my opinion that just about anything else you can build out of a Hi-Flier kit is probably better than a Hi-Flier.

I started this focus on the conduits because I figured I'd just make them out of square strip stock, so I looked up the size. Due to the quantum nature of commercial wood supply, it's hard to find something that is "close enough" in most scales. So I started thinking about printing them. To print it, you have to design it, and to design it, you have to make it a shape. So I wanted to figure out what shape to make it.

 

[bjphoenix]

Plus, your build lends support to my opinion that just about anything else you can build out of a Hi-Flier kit is probably better than a Hi-Flier.

I think the Estes ESAM, Estes HiFlier XL and even the Mean Machine are good sources for parts to bash into something else. I recently built an Estes Vapor so should include that one too. I built a clone of the Centuri AeroDart, I thought the Mean Machine nose cone was a little better fit so I used that kit, plus I had leftover pieces of BT-60 for other builds. I do have a HiFlier XL built stock too. I decided that long BT-60 models are fun on D12 motors on a good sized launch field, so I've got the HiFlier XL, 2 versions of the ESAM, the Vapor, the AerobeeHi, the Aerodart, and also I downsized the Wildman Darkstar to BT-60.

 

[Ez2cDave]

This is the 100:

Very nice . . . What is the source for those drawings ?

Are there more drawings availble ?

Dave F.

 

[tsmith1315]

What is the source for those drawings ?

Those are Aerojet drawings.

 

[Ez2cDave]

This is the 100:

Very nice . . . What is the source for those drawings ?
Are there more drawings availble ?

Those are Aerojet drawings.

Do you have more drawings of the AEROBEE 100, from Aerojet and are you willing to share them ?

 

[tsmith1315]

Do you have more drawings of the AEROBEE 100

Check your PM.

 

[Ez2cDave]

Check your PM.

Just did . . . Thanks !

 

[OZRoc]

I'm building a roughly 1/2 scale Aerobee for my L3 and I'm just going to go with PVC conduit split down the middle.
Cheers