Mercury Escape Tower Rocket

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lakeroadster

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I meant what method were you going to use to construct it. Seems like something the laser could knock out quickly, but back in the day, many people stick-built the structure. Since yours was more of a 10ft model vs a 6" model at this stage, I was just curious.

It seems that you might be changing directions with the purchase of the 1/12 model, though, so no need to get into the details if you don't want to.

Sandy.
A 3 sided box... made from cardboard, or perhaps 1/32 balsa. Then use small body tubes or straws attached to that to simulate the 2" and 1" tube that was used on the real thing.

or, better yet,

I've thought about making a plunger arrangement where a small rod runs from the cluster motor down through the capsule. The ejection charge lifts the plunger / rod, which trips a clasp on the bottom of the capsule to release the parachute. That would allow for an open tower.
 

Gus

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The MRC 1/12 scale capsule will look very undersized for 24 mm motors. It will also be very heavy.

There is a really good reason no one else has built a flyable pad abort model in the 15 years since Gordy and I built ours and documented here how we did it. To be successful you have to build strong but extremely light, and that's not something you ever read about on these forums. The Apollo Pad Abort, with four canted 24mm motors, is just barely doable. A realistic Beach Abort, with just 3 motors is probably not doable.

You really should read completely through the very long thread about the prior attempt at building a Beach Abort model. Especially posts 123 and 234. That thread is a great example of what not to do. You will not be successful without having a successful boilerplate first.
 

lakeroadster

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The MRC 1/12 scale capsule will look very undersized for 24 mm motors. It will also be very heavy.

There is a really good reason no one else has built a flyable pad abort model in the 15 years since Gordy and I built ours and documented here how we did it. To be successful you have to build strong but extremely light, and that's not something you ever read about on these forums. The Apollo Pad Abort, with four canted 24mm motors, is just barely doable. A realistic Beach Abort, with just 3 motors is probably not doable.

You really should read completely through the very long thread about the prior attempt at building a Beach Abort model. Especially posts 123 and 234. That thread is a great example of what not to do. You will not be successful without having a successful boilerplate first.
OK Gus.. I get your point. Thanks.
 

lakeroadster

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The UPS guy brought the Mercury Capsule today. The detail is awesome.

I weighed the components I'll be using and plugged the data into the Open Rocket simulation that I created. The (3) D motor's are up to the task of lifting it to a little over 500 feet.

Here are some photo's..
 

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Gus

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What was the weight?
 

Gus

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6.8 oz? That seems remarkably light. Does that include all of the capsule pieces, tower pieces, motor mount, escape rocket, parachutes, shock cord, wadding, and motors?
 

lakeroadster

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6.8 oz? That seems remarkably light. Does that include all of the capsule pieces, tower pieces, motor mount, escape rocket, parachutes, shock cord, wadding, and motors?
No Gus, that's the weight of the parts from the kit.

The total simulated flight weight, including the (3) D motors is 14.3 ounces. I'll update the simulation as I create the various parts. That's my SOP when it comes to scratch builds.

12-03-2021 Open Rocket Simulation.jpg
12-03-2021 Open Rocket Simulation Plot.jpg
 
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Gus

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If you can keep it at that weight you may have a shot. I figure for 3 canted D12s 15 oz is the max. Good luck. Looking forward to seeing the build.
 

lakeroadster

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If you can keep it at that weight you may have a shot. I figure for 3 canted D12s 15 oz is the max. Good luck. Looking forward to seeing the build.
The motor's are canted 15 degrees. While any canting affects the lifting capacity, (3) D12's can safely lift a lot more than 15 ounces. The 15 degree canting is about a 4% derating.

Per Estes:
D12-3 max lift weight is 14 oz.,​
D12-5 max lift weight is 10 oz.​
no data for a D12-7​

Using (3) motors, let's say 10+10+14 = 34 oz max lift weight, de-rated for the 15 degrees = 32.8 oz max lift weight.

Would I be comfortable with trying to launch a 32 ounce rocket with (3) D12 motors? No.

But saying 15 ounces is the max. lift weight capacity for (3) D12's, that's overly conservative, especially if we use a simulator, such as Open Rocket, to help us analyze launch data.
 
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Daddyisabar

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F
The motor's are canted 15 degrees. While any canting affects the lifting capacity, (3) D12's can safely lift a lot more than 15 ounces. The 15 degree canting is about a 4% derating.

Per Estes:
D12-3 max lift weight is 14 oz.,​
D12-5 max lift weight is 10 oz.​
no data for a D12-7​

Using (3) motors, let's say 10+10+14 = 34 oz max lift weight, de-rated for the 15 degrees = 32.8 oz max lift weight.

Would I be comfortable with trying to launch a 32 ounce rocket with (3) D12 motors? No.

But saying 15 ounces is the max. lift weight capacity for (3) D12's, that's overly conservative, especially if we use a simulator, such as Open Rocket, to help us analyze launch data.
Comfort is a rare beast when flying oddroc abominations!

Apogee website has the formula fer figurin' out the loss on da cant angle if ya have the smarts.

32.8 power and 32 lift off weight...Don't be wimpy, press the dern button!
 

lakeroadster

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More weight and power up front! Cluster E12 motors (Maybe Two plugged E12 0 and the other E12 whatever to eject.) Will it look good? Damn the torpedoes!
Pretty sure I'll never launch a rocket that's a scratch built design of my own on an Estes E motor.

Comfort is a rare beast when flying oddroc abominations!

Apogee website has the formula fer figurin' out the loss on da cant angle if ya have the smarts.

32.8 power and 32 lift off weight...Don't be wimpy, press the dern button!
yep... 15 degrees = 96.5% of vertical: 32.8 x .965 = 31.65 or about 32 ounces. Chief SOHCAHTOA is a wise man.
 

lakeroadster

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How about 3x Aerotech F39T? Blue thunder propellant lights very easily for clusters.
I'd fly that.
-Ken
For real?

That wakes things up a bit! What's the characteristics of the nozzle exhaust, pretty tight - choked flame pattern, or will it melt the capsule into a black blob of sadness?
 

Daddyisabar

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For real?

That wakes things up a bit! What's the characteristics of the nozzle exhaust, pretty tight - choked flame pattern, or will it melt the capsule into a black blob of sadness?
If the cant angle ain't right it won't matter. BP has a lot of heat, flame and particulates out of that mighty D clay nozzle, AT blue thunder couldn't be that much worse...right? I have only flown a two 18mm composite cluster on the P61 Black Widow and didn't notice any difference.
 

new2hpr

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The little Blue Thunder motors have a pretty small, very clean flame. Not very impressive, except the thrust! I flew a cluster of 3 in the Hot Pink Suppository of Discomfort. That calculated out to about 40g's leaving the rod. Fun times. 3 F24 White Lightnings were more impressive visually and audibly, though.
-Ken
 

neil_w

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If we're talking Blue Thunder, you also have the single-use E30T, which be well-suited here if the goal is to get things moving as quickly as possible.
 

Gus

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I just read up on the MRC Mercury capsule. I didn't realize it is just 6.25" diameter, much less than my Pad Abort or what the previous Mercury Beach Abort thread attempted. So the drag will be much less and you won't need nearly as much power to pull it. Three 24 mm motors should be able to lift it but will look a tad outsized. But should still be fun. I'd really think strongly, though, about canting them at least 30 degrees, and that may not even be enough to prevent them melting the capsule.

I still strongly suggest doing a boilerplate. Just a 6.25" disk of foam board at the bottom, then a straight piece of BT50 or 60 at the appropriate length up to your motor mount, to test the lifting capacity and parachute deployment. Even that flat piece should give you a good idea if the motor exhaust is going to impinge on the capsule.
 

lakeroadster

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I just read up on the MRC Mercury capsule. I didn't realize it is just 6.25" diameter, much less than my Pad Abort or what the previous Mercury Beach Abort thread attempted. So the drag will be much less and you won't need nearly as much power to pull it. Three 24 mm motors should be able to lift it but will look a tad outsized. But should still be fun. I'd really think strongly, though, about canting them at least 30 degrees, and that may not even be enough to prevent them melting the capsule.

I still strongly suggest doing a boilerplate. Just a 6.25" disk of foam board at the bottom, then a straight piece of BT50 or 60 at the appropriate length up to your motor mount, to test the lifting capacity and parachute deployment. Even that flat piece should give you a good idea if the motor exhaust is going to impinge on the capsule.
You like that word... boilerplate. :awesome: I just find it a weird term. I spent my career designing and building ASME pressure vessels, some of which were used in conjunction with boilers... and using the term boiler plate (crazy heavy steel plates) in relation to anything that you want to launch, just seems nuts. I know, it's a NASA term, but it's weird.

In this case, the boilerplate, is the actual rocket.
 

Gus

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I use the word "boilerplate" because that's the word that people who actually know how to do this kind of thing use to describe the first step in getting difficult designs to work.

"In this case, the boilerplate, is the actual rocket."

Yep, same as that last thread about a Mercury Beach Abort. I expect the same result.
 

lakeroadster

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I use the word "boilerplate" because that's the word that people who actually know how to do this kind of thing use to describe the first step in getting difficult designs to work.

"In this case, the boilerplate, is the actual rocket."

Yep, same as that last thread about a Mercury Beach Abort. I expect the same result.
Thanks for the optimism, Gus. Geeze... lighten up. We all have our own ways of doing things.

You can see in the video below that the flame pattern on a D12 is pretty tight.

 
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lakeroadster

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Spent 2 days working on modeling and making drawings.

What I ended up with is a BT-50 & C-50 tube running from the cluster motor down into the capsule, and a BT-80 inside the capsule to hold the laundry. The tower is made from 3/16" dowels that run from the cluster down through the capsule through / to the centering rings. I also added some centering rings in the tower that tie the dowels to the body tube.

Should make for a pretty stout mast, and since the dowels are one piece, that should add to their strength also.

The model shows a weight of 15.99 ounces

There are 12 drawings, see post #61 for the other 3.

Updated 01-04-2022

Mercury Capsule Abort Dwg Sheet 1 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 2 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 3 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 4 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 5 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 6 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 7 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 8 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 9 of 17 Rev 09.jpgMercury Capsule Abort Dwg Sheet 10 of 17 Rev 09.jpg
 
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