Model Rocket out of Styrene?

[Macdaddy4738]

Im talking about one that uses an Estes engine and actually launches. Is building it out of styrene possible? If so...how?

[naoto]

Folks have built plastic model conversions. Typically you end up having to use the higher power motors due to the weight (not only will the styrene be heavier than the usual paper and balsawood, but typically plastic models require extra noseweight).
http://members.aol.com/GCGassaway/PMC/PMC.htm
http://www.cybertravelog.com/qcr/model.html

Some Estes rockets are mostly plastic
http://www.ehobbies.com/est0807.html
http://www.ehobbies.com/est1890.html
http://www.ehobbies.com/rk-est-1203.html
http://www.ehobbies.com/rk-est-1202.html

Havent bought any of the Quest Micro Maxx stuff so I'm not sure what kind of plastic they're using
http://www.ehobbies.com/rocketry-rocket ... -sale.html

[Andrew Gorman]

MPC made a styrene Titan IIIc and maybe an R-7 that could also fly, if that's any help. Put a carboard or wood layer between hot gasses and plastic and anything is possible!
Andrew

[Macdaddy4738]

ah cool thanks!

What about multi stage rockets? How could i get 2-3-4 engines going at the same time? or is it possible..

[naoto]

ah cool thanks!

What about multi stage rockets? How could i get 2-3-4 engines going at the same time? or is it possible..

Using multiple engines that are lit simultaneously is known as "clustering". The old Saturn V kit from Estes used to use a cluster of 18mm engines (the later release uses a 24mm engine). The greater the number of engines, the tricker it can becomes, as you run a higher risk of asymmetric thrust profile because all the engines don't light. Staging has been done as well, and there are several kits currently available that use this. You could also mount the engines at an angle so the line of thrust for each engine goes through the CG of the model -- though this again becomes tricky. Considering that one the heaviest component of a model rocket tends to be the engine itself, multi-engine configurations tend to have the CG shifted toward the rear, resulting in a stability problem. Usually you offset this with bigger fins (more drag), or noseweight (more weight). Although one might think that moving the engine to the front (sort'a like Goddard's first liquid fuel rocket) would resolve the problem because it's "pulling", that's not really the case (and yes, it's been tried and was found to be unreliable).

Considering that you're asking these questions, it sounds like you've never built nor flown a model rocket. If that's the case, I'd strongly advise you to build and fly a few "simple" ones first before you try getting into PMC, staging or clustering. Trying to combine all of these into your first model rocket is a sure recipe for disaster.

[Matt2893]

With enough power, anything can fly!!!
http://www.scifi.com/masterblasters/

"*DON'T TRY THIS AT HOME*"

[Macdaddy4738]

how is it that i could launch multiple engines? what would have to be done?

[publiusr]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

[Macdaddy4738]

how do the cluster engines work? what do i need to do to get them to work?

[naoto]

Basically clustered engines are lit the same way single engines are lit -- with an electrical ignition system -- minimally it's a 12' ~ 15' electrical cord, a battery (e.g. 6V lantern battery), a switch, a pair of clips to hold the igniter (either the type included with engines or a length of nicrome wire). Igniters for two-engine clusters are typically wired up in parallel. When you get into 3 or more engines you generally have to use a "clip whip" which increases the number of leads to wire up the igniters (basically these things look like a hydra). Basically you don't want to be wiring up the igniters in serial. Typical ignition systems you find with starter sets using 6V battery work OK up to 2 or maybe 3 engines, and beyond that you'll need something that'll put enough current to heat up the igniters (but not to the point of overpowering them -- otherwise the igniters will simply burn through w/o igniting the engines).

As for staging, typically you see variations on the "pop-n-go" type, where the upper stage engines are either butted up against the lower stage engines, or separated by a short tube. Basically the lower-stage engines lack a delay and ejection charge that the single and upper-stage motors have. When the lower stage engine burns through, hot gasses and particles of burning fuel get blown into the nozzle of the upper stage engine. This in turn ignites the upper-stage engine. When butted together, the upper stage and lower stage engines are taped together, so that there is enough tiime for the upper engine to be ignited (otherwise the pressure after burn-through of the lower stage will blow apart the stages before the upper stage engine can ignite). When separated by a short tube, there is often a pressure relief vent (basically a small hole) so that the pressurization doesn't blow apart the stages before the upper engine can ignite. Although electrical systems can be used to ignite the upper stage, they carry a weight and complexity penalty (the added complexity could also pose a reliability problem).

A minimalist approach to a staged model rocket is the "rack rocket". The tail end of the rocket consists of a frame-like assembly where the fins are attached. The engines are simply stacked on top of each other, so that the lower stages get ejected out the back. Though quite effective, the practice of ejecting engines w/o some recovery device is frowned upon (they do pose a safety hazard).

[naoto]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

Hmm.. PMC in reverse. Plastruct does offer various sizes of tubes as well as sheet plastic. We do end up with an extra pair of nacelles from the PL kit too...

[Matt2893]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

how 'bout a USS Atlantis Refit?!?!
http://www.siriusrocketry.com/sirius00.htm

[Macdaddy4738]

if i where to use the tube method with the relief hole, and had 2 regular motors, both with ejection charge, is it possible to rig up a system where the ejection charge will ignite the second engine AND blast itself out from the back of the rocket taking the first stage with it?

[publiusr]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

how 'bout a USS Atlantis Refit?!?!
http://www.siriusrocketry.com/sirius00.htm

A bit steep--and a bit big. But it looks to be in about 1:350 scale as well. Its more chunky nacelles might make for a good bash of the Refit.

[naoto]

if i where to use the tube method with the relief hole, and had 2 regular motors, both with ejection charge, is it possible to rig up a system where the ejection charge will ignite the second engine AND blast itself out from the back of the rocket taking the first stage with it?

You generally wouldn't want to have any delay on the booster engines -- otherwise your rocket will be pointed downward by the upper stage lights! The pressure of the gasses generated upon ignition of the second stage is enough to blow apart the first and second stage. The taping of the engines when you butt them together is done to delay the separation. When you've got the short ducting tube between the lower and upper stages, the pressure relief hole does a similar job by delaying the separation. In either case, the sudden pressure buildup from the upper stage ignition is what blows apart the stages. The stages are built in a way so that they come apart fairly easily (though not loose to the point that the lower stage will fall off by itself).
Again, as I had stated earlier, you probably want to get some experience in building and flying single-engine and single-stage rockets before you try to venture into clustering and multi-stage. You don't want to attempt plastic model conversion without having a good idea of what makes a model rocket stable.

[naoto]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

how 'bout a USS Atlantis Refit?!?!
http://www.siriusrocketry.com/sirius00.htm

A bit steep--and a bit big. But it looks to be in about 1:350 scale as well. Its more chunky nacelles might make for a good bash of the Refit.

The kit shown on that page is 1/3 the size of the high-power model. Described as 37" -- so it's a bit less than 2x the size of the Estes kit (I'm assuming it used a standard 18" length of BT-50). Still kind'a big.
Personally I'm thinking about building a mini version of the original for the 13mm engines. Amongst the other mini versions I'm thinking about include a mini version of the classic Interceptor (basically works out to around 70%). Making a micro version for the Quest MicroMAXX engines might prove to be an interesting challenge.

[M3]

I would have liked to see small plastic replicas of actual flying rockets--a 1/1000 USS Atlantis TOS

Hmm.. PMC in reverse. Plastruct does offer various sizes of tubes as well as sheet plastic. We do end up with an extra pair of nacelles from the PL kit too...

I'm still working on mine... She's currently in first coat primer, and after a bit of sanding, painting, decalling, and sealing, she's going to be part of a refueling dio- with a Connie parked on the top of her flight deck, and a Saladin attached to the bottom of her ventral "fin".

More pics soon.

[Macdaddy4738]

ok, so do i still need a booster engine?

What i wanted was a total of 3 engines, each with 2 stages...

i wanted a main center tube, with 2 smaller tubes on each side...if you can picture it...how would i rig up a system to ignite all 3 engines at the same time?

[Umi_Ryuzuki]

Unbend a paperclip and then form it to match the outside diameter of your rocket bodytube. Insert the three engines so that one end of each igniter wire faces into the center of the cluster. Twist the three centered wires together. Bend the other end of each igniter wire out and then around the paper clip. Be sure to wrap them tightly or use an alligater/micro clip to secure the wires to the paper clip.

Now clip one microclip from the launch system to the three twisted center wires, and the second microclip of the launch system to the paperclip.

[naoto]

ok, so do i still need a booster engine?

What i wanted was a total of 3 engines, each with 2 stages...

i wanted a main center tube, with 2 smaller tubes on each side...if you can picture it...how would i rig up a system to ignite all 3 engines at the same time?

Typical model rocket flight profile:
http://www.estesrockets.com/Flight_Profile1060.html

See the following link regarding Estes rocket engines
http://www.estesrockets.com/Engine_Facts1062.html

BTW, I strongly advise reading the Handbook of Model Rocketry if you're new to model rocketry. Pretty much the "Bible" for model rocketeers.
http://www.amazon.com/exec/obidos/tg/de ... 9?v=glance

Yes, there are technical reports and software I can point out that'll help in a scratchbuild model rocket, but I'd hesitate as it seems like you're just starting out with model rocketry (judging from the questions you're asking).

[Macdaddy4738]

ive done alot of model rocketry, but this is my first foray into multi stages and multi engines...

[naoto]

Interesting... From the questions you were asking it seemed like you weren't familiar with "standard" references like the Handbook of Model Rocketry. Had you read this text or the Alpha Book of Model Rocketry, you would've had some idea about how clustering and staging. Haven't bought a starter kit recently to see if the Alpha Book on Model Rocketry is included (it used to be included in the starter sets back when I got started in the mid 1970s). My guess is that such materials are no longer included.

Anyway... If you don't already have the Harry Stine book, go out and pick up a copy! Lots of useful info in there. Admittedly I hadn't owned a copy until recently (though I did check it out often from the local public library back when I got started).

Yep, I still have the cardboard box that my original starter set came in (it became my range box). It's seen a bit of usage, and has a lot of patched-up areas (like where the plastic handle went into the cardboard top).

[publiusr]

how 'bout a USS Atlantis Refit?!?!
http://www.siriusrocketry.com/sirius00.htm

A bit steep--and a bit big. But it looks to be in about 1:350 scale as well. Its more chunky nacelles might make for a good bash of the Refit.

The kit shown on that page is 1/3 the size of the high-power model. Described as 37" -- so it's a bit less than 2x the size of the Estes kit (I'm assuming it used a standard 18" length of BT-50). Still kind'a big.
Personally I'm thinking about building a mini version of the original for the 13mm engines. Amongst the other mini versions I'm thinking about include a mini version of the classic Interceptor (basically works out to around 70%). Making a micro version for the Quest MicroMAXX engines might prove to be an interesting challenge.

I'd love to see Atlantis and the interceptor in plastic. I wonder if they still make the clear see through educational rocket over at ESTES...

[naoto]

The Phantom is not listed in the catalog. I would assume it's out of production.

[Jediguy]

darn , model rockets arent allowed in my country. sounds like im missing out on a lot of fun.

[naoto]

Gonna have to try these out one of these days.
http://antigravityresearch.com/

[publiusr]

The ring fin set is good scratch material.

I can't believe they had a two-stage water rocket there.