Never Been Done In Model Rocketry !...(?)

[sandman]

James

Great pics. I actually have the whole declassified Merc capsule design manual. There is incredible info in it. Every detail of every system and component of the capsule inside and out.

I will be starting on the maid body again today. I'm having to print off every thing at a 30% reduction through photo shop. That percentage looks like it's going to be about right.


Rocketbuilder
In response to post 23. This part of the construction in the pics is about four to five hours of work. As far as the weight , I won't know that untill I get it together and weigh it. There's so many parts, I'd have to print and cut out every thing then weigh it all. I have to make the shingles for this thing...AGAIN. There's 1,300 dimples (if I rember correctly) to cut out, on the 1/4 it was tedious enough, I can't emagine what it's going to be like at a smaller scale. Here of some pics of the first shingle build.

The amount of work involved with detail and documentation if fine, Gus and I did it on ours.

But, we did what NASA did back then. We built a boiler plate version first just to see if it would work.

I say make the boiler plate version simple at first, just to see if it even works. Make the capsule roughly to shape with cardstock. The tower on the boiler plate could be a body tube.

Concentrate on the propulsion unit design. Get that to fly and jettison a parachute.

Then make a final model with details.

 

[[POW]Eagle159]

I would say to try it out on a plane unpainted/finished prototype to see if it actually works and test it out before putting all this detail into an untested rocket...

Ahh, I see that sandman beat me to our point.

 

[sandman]

I would say to try it out on a plane unpainted/finished prototype to see if it actually works and test it out before putting all this detail into an untested rocket...

Ahh, I see that sandman beat me to our point.

Hey...I hear an echo.:smile:

 

[luke strawwalker]

Thanks Luke I konw I can cout on you'r vast rocketry knowledge. I learned this from you'r replies on PM, you were the insperation for the Atlas rebuild. My only problem is I have to read and reread you'r replies to get my brain wrapped around all the info.

You're welcome... If in doubt or you want it explained better than my meager abilities, check out "The Handbook of Model Rocketry" by G. Harry Stine and Bill Stine, or Tim Van Milligan's "Model Rocketry Design and Construction, third edition" from Apogee Rockets. Both are EXCELLENT books!

Later and good luck! OL JR

 

[luke strawwalker]

1300 dimples to cut out?! :y: Why do you do this to yourself?
Sometimes you just have to sacrifice detail for practicality. Trust me, it's worth your sanity.

Closetastronaut is a dedicated paper modeler, and one that does immaculate and incredible work, lemme tell you (if you're not a member of the papermodeler's forum, which I HIGHLY recommend!) SO this isn't surprising that he'd want to make a museum-quality build since that's what he's used to doing with his other papermodels...

BUT, a word of advice... flight models have the bad habit of getting dinged up badly or destroyed outright... you might want to build less detailed models to work the bugs out of the flight regime and do "everyday flying" and THEN, if you're so inclined, do the super-detailed uberquality build... heck take it NARAM and take the scale competition by storm... but starting out with the extreme high quality model when you haven't even worked the bugs out of the flying part, that's EXTREMELY likely to end in heartbreak...

Plus, you can incorporate whatever "lessons learned" through testing into your final high quality model, and not have the difficulty of making changes and having to incorporate them into an already constructed airframe and model...

Just a suggestion to add to your happiness and reduce frustration... Nothing's more heartbreaking than an immaculate rocket that crashes and splinters into a thousand pieces of junk on its first flight!!

Later! OL JR

 

[closet astronaut]

1300 dimples to cut out?! :y: Why do you do this to yourself?
Sometimes you just have to sacrifice detail for practicality. Trust me, it's worth your sanity.

You'r right but the dimples on the Merc are the biggest visual characteristic. It would look lame if I just wrapped it in black paper. On the plus side, the shingles are two piece giving increased structural strength. The biggest problem with paper models is crushing and denting. The larger the model, the broader the parts the easier they dent when handled. Paper mods are great if something breaks or is torn or falls off, they're easy to fix, if needed you can just print off a new part, cut, glue and install. However, when one gets a dent or crush it's usually large area of the model, a main part of the body where the only option is a complete rebuild.

As large as this thing's going to be, plus falling from an estimated hight of 80' it's going to need all the strength I can build into it.

 

[closet astronaut]

Gentlemen

I appreciate you'r advise and concern but there are a few things you need to know. I've seen the previous builds of this idea, others have already pioneered this project and did it successfully so my confidence in flight is strong.

The next thing is I've built this before at a MUCH larger complexity and scale, ( https://www.papermodelers.com/forum...13124-journey-begins-1-4-mercury-capsule.html ), this build will be a walk in the park. I took this model WAY past what the designer intended, ( https://www.spacecraftreplicas.com/ ).

Being made from paper the only thing I'll have invested is time. If there is CATO, it will be on film and what ever is dammaged or destroyed I'll just print off what ever is needed and build it again. If I wasn't building this it would just be something else. As I stated in a previous thread, for me it's all about the build.

The biggest problem I'm facing now it where to put it when it's done. This is why I've moved from static model building to mods that fly, and rockets take up less room. Here are some pics to give you an idea of my delima, and scale size of the first build. Any one interested in a 1/4 Merc capsule?

 

[skybuster]

It's ironic you bring up this idea, the next project I have on the slate is a 1/48 scale third stage Sat-V flying model.

That is awesome! I'd love to build one that has all the stages like the real one, just need the skills!

 

[WaldoT]

Great thread. Subscribed!

 

[closet astronaut]

A quick update. The second build, at 30% reduction of original files. I think this is going to give me what I'm looking for. I will continue on from here.

So.. for you mathamaticians out there, a 1/4 scale Merc reduced 30% = ?

 

[mbauer]

CA

Another great build in progress! You ask about the 1/4 scale Mercury, ever thought about donating to a museum? Or a Challenger Learning Center?

Once Ken West's Apollo is available, my plan is to make two, one for the local Challenger Center here in Kenai. The other will be mine.

If I understand this right, you want to deploy a chute from the capsule after the LES seperates? Have you checked out a Texas Timer? i.e.-small wind up toy motor that the water rocket rocketers use to deploy their chutes.
https://www.texastimers.com/ lower left hand side menu bottom button called plastic clocks.

Testing one now for use in my air powered rockets. Have had luck using one in some ground tests, now in process of modifying/correcting issues for an actual test flight.


Mike

 

[luke strawwalker]

CA

Another great build in progress! You ask about the 1/4 scale Mercury, ever thought about donating to a museum? Or a Challenger Learning Center?

Once Ken West's Apollo is available, my plan is to make two, one for the local Challenger Center here in Kenai. The other will be mine.

If I understand this right, you want to deploy a chute from the capsule after the LES seperates? Have you checked out a Texas Timer? i.e.-small wind up toy motor that the water rocket rocketers use to deploy their chutes.
https://www.texastimers.com/ lower left hand side menu bottom button called plastic clocks.

Testing one now for use in my air powered rockets. Have had luck using one in some ground tests, now in process of modifying/correcting issues for an actual test flight.


Mike

Apogee rockets sells a staging timer (electronic) that would be perfect for use in just such an application. You don't even have to use black powder to eject the parachute... a simple spring-loaded mechanism with a burn-string to activate it, with the burn string burned through by the staging timer's circuit when the timer fires an ignitor to burn the string, can eject the parachute when needed. Rocket electronics are truly tiny nowdays and the price is coming down all the time...

Later! OL JR

 

[closet astronaut]

Made some decient progress today. Finished the main and recovery section. Next phase will be the main body tube the diameter of the recovery section, it will run from top through the heat shield into the retro pack.

 

[Scotty Dog]

Reminds me of when I was a wea lad.
I Uued to get books of paper cut-out projects.
Anywhoo-

 

[Rocketbuilder]

Wow, excellent work once again! How long did that take?

Scotty, those look kinda like marshmellons to me... :wink:

 

[Fred22]

Gentlemen

I appreciate you'r advise and concern but there are a few things you need to know. I've seen the previous builds of this idea, others have already pioneered this project and did it successfully so my confidence in flight is strong.

The next thing is I've built this before at a MUCH larger complexity and scale, ( https://www.papermodelers.com/forum...13124-journey-begins-1-4-mercury-capsule.html ), this build will be a walk in the park. I took this model WAY past what the designer intended, ( https://www.spacecraftreplicas.com/ ).

Being made from paper the only thing I'll have invested is time. If there is CATO, it will be on film and what ever is dammaged or destroyed I'll just print off what ever is needed and build it again. If I wasn't building this it would just be something else. As I stated in a previous thread, for me it's all about the build.

The biggest problem I'm facing now it where to put it when it's done. This is why I've moved from static model building to mods that fly, and rockets take up less room. Here are some pics to give you an idea of my delima, and scale size of the first build. Any one interested in a 1/4 Merc capsule?

Man that stuff looks awesome.
Cheers
Fred

 

[closet astronaut]

Wow, excellent work once again! How long did that take?

Maybe six hours, it's kinda hard to be acurate, the build time is broken up by life.

 

[closet astronaut]

More progress. WOW I forgot how scratch building and making every part from imagination slows the build process. Main tube done I'll need to extend it abit more to reach the end of the retro pack but that will be done later.

I used card board for the centering and structuring rings, they make the whole structure incredibly strong. The next phase will be building the antenna cap and fitting it, after this is complete, before building the LES I will be working on the deployment of the cap as it will be part of the LES.

 

[[POW]Eagle159]

NICE, You do some pretty good cutting there!

I cut out cardboard centering rings from scratch also, but they arnt that good! (but Im getting better)

 

[closet astronaut]

Getting down to brass tacks now...where the rubber meets the road. At this point I'm going to have to figure out the mechanics of secure attachment, release, and chute ejection. No point in going any further untill this bit of engineering is done. There's plenty of space inside the cap for mechanical parts and electronics.

 

[closet astronaut]

Ok..so here's what I got so far. This is the vision I keep seeing. I built up a proto type today from toung depressors, lolly pop sticks and card board. It does work but these materials aren't strong enough. There's a few bugs that still need to be worked out. It's going to need some type of star and worm gear with a shaft to extend out side the cap to extend the locking tabs and then some type of triggering mechinism to retract the locking tabs in flight.

 

[luke strawwalker]

Ok..so here's what I got so far. This is the vision I keep seeing. I built up a proto type today from toung depressors, lolly pop sticks and card board. It does work but these materials aren't strong enough. There's a few bugs that still need to be worked out. It's going to need some type of star and worm gear with a shaft to extend out side the cap to extend the locking tabs and then some type of triggering mechinism to retract the locking tabs in flight.

Looks good... now put a bellcrank on it powered by a rubber band to retract the "locks" and held stretched out to keep the locks engaged until the burnstring is severed by the ejection charge, and you're there... Might need a light spring to push everything apart... a rubber band pulling a small dowel downward through a hole to push everything apart might work wonders...

Later! OL JR

 

[closet astronaut]

Looks good... now put a bellcrank on it powered by a rubber band to retract the "locks" and held stretched out to keep the locks engaged until the burnstring is severed by the ejection charge, and you're there... Might need a light spring to push everything apart... a rubber band pulling a small dowel downward through a hole to push everything apart might work wonders...

Later! OL JR

Wish I could see what you have pictured in you'r head.

 

[luke strawwalker]

Wish I could see what you have pictured in you'r head.

I'll see what I can cook up... Later! OL JR

 

[luke strawwalker]

OK here we go... here's a quick diagram I drew up in MS PAINT. This should help explain what I'm thinking.

Basically you extend the "axle" with the latch bellcranks at the center of your latch assembly to include another bellcrank directly above (or below) it. This bellcrank will have a rubber band, stretched to provide sufficient force to pull the bellcrank around and retract the latches when released. The other end of the rubber band is attached to a post or hook, probably the easiest would be a wood dowel sticking up from the baseplate that the latches are attached to. This provides an anchor point for the rubber band to pull the bellcrank when the burn string is released.

The mechanism is held "locked" against the rubber band tension by the burn string. Basically this is a piece of thread that is run up over the top of the rocket motor which, when the ejection charge fires, is instantly burned through or severed by the force and heat of the motor's ejection charge, releasing the rubber band to then pull the bellcrank over, and retract the latches, allowing the two components held by the latches to separate.

Make sense??

Good luck! Later! OL JR

 

[luke strawwalker]

Here's a picture of your latch mechanism doctored in MS PAINT... maybe that will show the simpler way of making the mechanism...

Later! OL JR

 

[closet astronaut]

Here's a picture of your latch mechanism doctored in MS PAINT... maybe that will show the simpler way of making the mechanism...
View attachment 91324
Later! OL JR

CLICK

Now I see how it works. Thats a pretty cool program you got there.


The burn string system I'm not sure would work in this application, it would have to stretch a long way, from the bottom of the cap to the engine placements.



The engines will be tucked up inside the bells.



The cap (antenna) will be double liped, one sliding down around the outside top of the recovery section and the locking mechenism will be inside the cap which will slide down inside the recovery section.




This is the original build for the 1/4 scale, this will be redesigned for this model. I'm almost done with the second proto type locking mechenism using balsa for the plate and styrene for the tabs, so far I'm not happy with the operation. Mike mentioned on the other forum not using four tabs, at first I wasn't sure it would work with two but after a little thought I might be able to go with two if i enlarge them. Looking at you'r first photo has given me an idea on how to change what I already have and simplify it, and possibly make the whole thing work better.

Thank you for the photos! These have got my brain churning in a new direction.

 

[luke strawwalker]

You're welcome... MS Paint has been on every computer AFAIK... (well, running Windows anyway). Think you can get shareware equivalent.

There's no specific REASON why a burn string wouldn't work... it might take a bit of engineering and you want to use string that won't stretch. The other alternative that jumps to mind is just to use a model airplane R/C setup with a microreceiver and microservo controlling the latches... but of course that will be heavier and more expensive... and require you to actually move the control to separate the two parts at the correct point in the flight... but then again, RC activated recovery isn't really anything new... John Pursley used it on his NARAM Saturn V a few years back, and I've heard of lots of other folks using it.

I'm interested to see what you come up with...

Later! OL JR

 

[closet astronaut]

Heres the second proto type, I couldn't get this operate smooth enough.



I tried to keep the amount of parts to a minimum but adding the extra arms shortening the tabs made it all operate smoother.



So...I've got the system worked out, theres a few minor bugs in this to be worked out later, but from this point I can continue the build of the cap and the mounting of the locking plate.

 

[Rocketbuilder]

Wow, that looks complicated! I hope it works for you.
Also, where did you get the screws in the first pic? I've been looking for some like that, but haven't been able to find any.