What to do with an Estes Olympus kit?

SolarYellow

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Not really interested in throwing eggs around. Bought a couple Estes Olympus kits when I saw them at HL, was thinking I'd bash them into an upscaled Goblin or two. But I got them home and measured stuff, decided the nose cone isn't really very Gobliny. So I have a set of BT-65 parts to do something with. Nose cone is basically Alpha-like. I already have plans for an M-104 Patriot and have the BT-60 kit incoming. So that would be silly.

Competing ideas are:
1. A biggish Alpha (because that's always on the table). Sure, there are BT-60 Alphas out there, but how many people have built a BT-65 Alpha? :)

2. A smaller than PSII, sorta-scale Doorknob. Because I have two sets of parts, I was thinking about doing a two-stage Doorknob. Because it's 1.8 inches and not 3 inches, you could actually get decent off-the-rod and first-stage performance with reasonable motors. The Doorknob booster is essentially full length, making it bigger than I want falling without a streamer or chute. One could always do composite motors with electronic ejection of the booster recovery gear and airstart the sustainer motor, but I kinda like the idea of just running a BT-50 stuffer connecting two 24mm BP motors and doing ignition the old-fashioned way. That leads to the technical problem of ejecting the laundry in the booster. Seems like it would be easy enough to use an Apogee or Quark to do an apogee deployment, but the chute or streamer would have to be packed annularly and you'd have an annular (donut) ejection charge volume. Anyone doing that? What problems does one run into? BT-50 OD is 0.976, BT-65 ID is 1.754, leaving 0.389/side radially to package the recovery systems. Interesting problem, but seems doable...

I'm trying to think of something fun, technically interesting and worthwhile to do with the two kits, as an alternative to just returning them. Something I'm not already planning to do with something else. Totally open to whatever brainstorms the collective comes up with.
 
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eugenefl

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I bought one of these as well since the size was substantial for a model rocket. Typically, I say it's blasphemy to do something other than the face card, but I'm with you on this kit. I wasn't a fan of the original design, but figured I could bash this into something else. Perusing some of the vintage rockets, I think the Estes Constellation would be a good design to build a tribute look-alike. The nose cone profile looks to be slightly off, but this is a sporty design that I think would work well with the parts that come in the Olympus.

 

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K'Tesh

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Use it to recreate/repair an Estes Cineroc. The BT-65 body tube is the perfect diameter for the camera body of the Cineroc.
 

SolarYellow

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Typically, I say it's blasphemy to do something other than the face card, but I'm with you on this kit.

I never build any rockets the way the instructions say to build them. I mostly look at a kit as a cheaper way to get a set of parts to build what I want than buying them all as parts.
 

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This thread dovetails with something I've recently wondered: what are the dimensions of BT-65? Perhaps I've been living beneath a cabbage leaf, but I'd never heard of the stuff until I saw some egg-related products on the Estes site a few days ago.

BT-5, -20, -50, -55, -60, -70, -80, I all know. I'm even aware of -56. But -65 was new to me.
 

eugenefl

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I never build any rockets the way the instructions say to build them. I mostly look at a kit as a cheaper way to get a set of parts to build what I want than buying them all as parts.

There's no wrong or right way to enjoy a kit (or it's parts)! From my youth I RARELY got rocket stuff. Our household had limited income so any money I came across was reserved for kits, specifically ones that were great looking out the gate. The challenge for me was to build it to look just like the face card, hence the nostalgia of building to the card's design. Enjoy the build and looking forward to see what you come up with.
 

SolarYellow

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Kit bags I have are still sealed, but I dug up some numbers from somewhere that say 1.754 ID, 1.796 OD with an 0.021 wall. Or 44.6 ID, 45.6 OD in Frost Inches.

ETA: Here - https://www.rocketryforum.com/threads/weird-tube-size-of-estes-olympus.173376/page-2#post-2292631
...both Green Eggs and Olympus use a BT-65 tube. It is 1.796" in Diameter. My own measurement of the wall thickness is 0.022", but it could be single sample variance.
With a 0.022" wall, ID = 1.752"
With a more to Estes standard 0.021" wall, ID=1.754"

There's a cardboard coupler on the Estes site. https://estesrockets.com/product/030182-bt-65-tube-coupler/
Dimensions are 4 inches long with an ID of 1.684 and OD of 1.744.

More discussion of the kit here: https://www.oldrocketforum.com/showthread.php?t=18149

The kits include 24mm MMTs and retainers. I have a couple 29mm retainer packs inbound; maybe I'll like it with these tubes and do something for the 29/40-120 case. As you say, it would be cool to have the knurled bit partly recessed, neatly nesting as a just-clearance fit in the ID of the airframe. Maybe cool enough to just do a simple 3FNC clipped-delta just to capitalize on that little elegance.

44mm is frustratingly too big to be a flush-fit tail treatment on BT-60.
 
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BEC

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As a reminder, the plastic parts in Green Eggs and Olympus are dimensionally identical — they only differ in color — so what applies to one applies to the other.

The nose cone is not at all "Alpha-ish", though if you stood way way back you might mistake it for a stretched Alpha III nose cone (elliptical rather than a tangent ogive). Actually, after doing a direct comparison, not all that stretched. This is a Green Eggs, but as I say, the plastics are the same in the Olympus except for the color.


IMG_6202.JPG

I have recently used this Green Eggs for multi-altimeter comparisons involving the new-to-me Eggfinder ION.


added: The 29mm Estes retainer ring almost fits inside the body tube of these models. This is the retainer from my Super Big Bertha, laid on the aft end of the Green Eggs.

IMG_6203.JPG IMG_6204.JPG

further added: I thought of upscaling the Constellation, too, as @eugenefl suggests. The nose cone on Green Eggs/Olympus is a little short to be an upscale BNC-50X....but with a little creative painting one could fake the look easily enough, I think. Hmmmm....... a ~2.5x upscale Constellation. Would need a longer clear payload tube.....
 
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K'Tesh

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If I can find 10" of the plastic BT-65, I've got a plan to build the Estes Eagle SCRV Space Camp Research Vehicle as an upscale.
 

SolarYellow

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Played with the camera vehicle concept a little. G64, electronic deployment with hot wire chute minder in the payload bay and Eggfinder Mini in the nose, clipped delta 3/32 ply fins. Guess on the weight for a tiny 1080P Chinacam. Sim is ~4100 feet. Stability factor is ~1.7, which means lots of room for things to change as it gets built. That could be fun and interesting. Guess I'll keep the kits. :)

The motor retainer is pasted in from (probably @K'Tesh's) Doorknob.ork file. Clearly, it's not quite accurate in size.

Estes Olympus 7293 outfitted 29mm.png
 

bad_idea

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added: The 29mm Estes retainer ring almost fits inside the body tube of these models. This is the retainer from my Super Big Bertha, laid on the aft end of the Green Eggs.
That's perfect, thanks. I don't actually want to waste diameter by sinking the retainer into the body, I just want it out of the airstream. I might have to pick up some of these parts sometime to help me dispose of my overbuy of Estes retainers. The other candidate is 1.88"/1.9," which is slightly larger (actually large enough to swallow the retainer) but has better coupler availability (can buy it 34" at a time from BMS) and may (or may not) have more choice of nose cones.
 

Scott_650

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That's perfect, thanks. I don't actually want to waste diameter by sinking the retainer into the body, I just want it out of the airstream. I might have to pick up some of these parts sometime to help me dispose of my overbuy of Estes retainers. The other candidate is 1.88"/1.9," which is slightly larger (actually large enough to swallow the retainer) but has better coupler availability (can buy it 34" at a time from BMS) and may (or may not) have more choice of nose cones.
People have sanded those retainers smooth - can’t recall who or when but it’s been discussed here on TRF - looks like that would be a viable option with the BT-65 tubes.
 

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I have sanded the Estes retainer smooth so it was the same diameter as the BT.
Think I started with a course file then used sand paper.
 
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KenECoyote

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K'Tesh

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If I can find 10" of the plastic BT-65, I've got a plan to build the Estes Eagle SCRV Space Camp Research Vehicle as an upscale.
Hey, I found my long plastic BT-65 fragment. It's 25.5 cm long, true scale would be 25.2 cm. I am not inclined to cut of a mere 3mm. However... it's a *TIGHT* fit. I'm thinking to heat it when trying to apply it to the other parts.
 

BEC

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Hey, I found my long plastic BT-65 fragment. It's 25.5 cm long, true scale would be 25.2 cm. I am not inclined to cut of a mere 3mm. However... it's a *TIGHT* fit. I'm thinking to heat it when trying to apply it to the other parts.
Just the opposite of the fit of the kit parts — adapter and nose cone to the payload tube — on the Olympus and Green Eggs — which requires some tape wraps to be tight enough (though the adapter fits the paper body tube nicely). I remember Will Marchant commenting on these different actual diameters on "BT-65" parts in the vNARCON 2022 Arduino project build, which includes using a Green Eggs or Olympus (or in his case, a hybrid, with the clear tube from an Olympus used on a Green Eggs) as the carrier rocket.
 

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Bought an Olympus at Hobby Lobby today for the cone and tube. Will design some rings and fins and have them laser cut.

Next time I have reason to buy from Estes, I'll order a coupler or two.
 

gldknght

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Not really interested in throwing eggs around. Bought a couple Estes Olympus kits when I saw them at HL, was thinking I'd bash them into an upscaled Goblin or two. But I got them home and measured stuff, decided the nose cone isn't really very Gobliny. So I have a set of BT-65 parts to do something with. Nose cone is basically Alpha-like. I already have plans for an M-104 Patriot and have the BT-60 kit incoming. So that would be silly.

Competing ideas are:
1. A biggish Alpha (because that's always on the table). Sure, there are BT-60 Alphas out there, but how many people have built a BT-65 Alpha? :)

2. A smaller than PSII, sorta-scale Doorknob. Because I have two sets of parts, I was thinking about doing a two-stage Doorknob. Because it's 1.8 inches and not 3 inches, you could actually get decent off-the-rod and first-stage performance with reasonable motors. The Doorknob booster is essentially full length, making it bigger than I want falling without a streamer or chute. One could always do composite motors with electronic ejection of the booster recovery gear and airstart the sustainer motor, but I kinda like the idea of just running a BT-50 stuffer connecting two 24mm BP motors and doing ignition the old-fashioned way. That leads to the technical problem of ejecting the laundry in the booster. Seems like it would be easy enough to use an Apogee or Quark to do an apogee deployment, but the chute or streamer would have to be packed annularly and you'd have an annular (donut) ejection charge volume. Anyone doing that? What problems does one run into? BT-50 OD is 0.976, BT-65 ID is 1.754, leaving 0.389/side radially to package the recovery systems. Interesting problem, but seems doable...

I'm trying to think of something fun, technically interesting and worthwhile to do with the two kits, as an alternative to just returning them. Something I'm not already planning to do with something else. Totally open to whatever brainstorms the collective comes up with.
Maybe get some super bright LEDs and make a night flyer?
 

techrat

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The Olympus is a "tall" rocket, as the BT-65 tube is decent length compared to Green Eggs. Dispense with the clear plastic, widen the payload bay with a BT-70 Tube section, and build yourself a semi-scale Falcon 9. Or since you mentioned having more than one, make a Falcon heavy and make a 3 motor cluster.
 

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I put some bright LED's in mine and used it for a night flight, on an AT E28-5. Worked great, although I broke a fin on landing and the clear plastic cracked where I had drilled holes for retaining push-pins.
 

bad_idea

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The Olympus is a "tall" rocket, as the BT-65 tube is decent length compared to Green Eggs. Dispense with the clear plastic, widen the payload bay with a BT-70 Tube section, and build yourself a semi-scale Falcon 9. Or since you mentioned having more than one, make a Falcon heavy and make a 3 motor cluster.
You could semi-scale the propulsion too. Sadly nine motors won't fit, but BT-65 can comfortably hold seven 13mm tubes.
 

Jacktango22

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I have purchased a few of these at HL for kit bashing purposes. Have designed them for various payloads such as video cam, altimeter, and the like. Shortened the tube and added 29 mm motor mount to latest version in process. Good fun.
 
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