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CrazyModelGuy

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So ive been into rockets since I was 10 or so. But always launched Estes and Quest rockets. I am getting a MadCow Rocketry "lil Goblin hopefully soon. First I read that It can use Reloadable motors but when I search those motors all that comes up is just the repacking stuff. Dont I need a "cannister" for it all to fit inside of? What am I missing. And lastly, the 'lil goblin ive been reading online and a few other sources the body tube is fiberglass but others say its cardboard. Im just looking for clarification.
 

ThirstyBarbarian

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Are you talking about this rocket? https://www.madcowrocketry.com/2-6-lil-goblin/

I’m pretty sure that’s cardboard, not fiberglass, so it’s not going to be very different to build than some of the rockets you are already used to. It will be similar to a larger, sturdier Estes kit.

There are reloadable motors that can work with that rockets, and you would need the appropriate motor cases, closures, hardware, etc. to use the reloads. I’d suggest starting off with some single-use motors to make it easier. You could use something like these F20 motors http://www.buyrocketmotors.com/aerotech-f20-white-lightning-econojet-29-mm-single-use-2-pack/ There are also F23, F27, F42, and F67 single-use motors sold this same way in 2-packs that will fit that rocket. You can search that vendor website for those. You would want to do a flight simulation of some kind to see how those would perform with your rocket. Some might be pretty high, and maybe you should keep it lower to start.
 

CrazyModelGuy

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Are you talking about this rocket? https://www.madcowrocketry.com/2-6-lil-goblin/

I’m pretty sure that’s cardboard, not fiberglass, so it’s not going to be very different to build than some of the rockets you are already used to. It will be similar to a larger, sturdier Estes kit.

There are reloadable motors that can work with that rockets, and you would need the appropriate motor cases, closures, hardware, etc. to use the reloads. I’d suggest starting off with some single-use motors to make it easier. You could use something like these F20 motors http://www.buyrocketmotors.com/aerotech-f20-white-lightning-econojet-29-mm-single-use-2-pack/ There are also F23, F27, F42, and F67 single-use motors sold this same way in 2-packs that will fit that rocket. You can search that vendor website for those. You would want to do a flight simulation of some kind to see how those would perform with your rocket. Some might be pretty high, and maybe you should keep it lower to start.
And what launch controller do you recommender for igniting higher power motors. I used to just use a motorcycle battery. Back in the day!
 

ThirstyBarbarian

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I think typically the igniters for composite motors like 12-volts. They will probably light with 9 volts or more, but 12 should be very reliable. So a car battery, motorcycle battery, jump pack, or combination of dry cell batteries that add up to 12 volts should work fine.
 

Scott_650

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And what launch controller do you recommender for igniting higher power motors. I used to just use a motorcycle battery. Back in the day!
The Estes #2240 Pro Series II Launch Controller is a good choice for the money if you don’t want to gin up your own - available discounted from online vendors for less than $30. There are others but they can get a bit pricey.

Nice thing about the #2240 Controller is you can power it with regular alkaline C cells or rechargeable Cs (I use NiMH rechargeables in mine) and it has a JST connector for a LiPo battery pack too.
 

mtnmanak

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The Go Box from Pratt is a classic and has been around for a long time. It is only a little more expensive than the Estes and, in my opinion, much better built. It can connect to any 12V power source you want:


Car batteries, motorcycle batteries, etc all work great, but I don't like lugging them around. LiPos are also great, but expensive. One of these cheap 12V lantern batteries lasts me a long time (last one I bought was in 2019 and it is still cranking LPR/MPRs into the air at our local park) and is pretty lightweight compared to other options:

 

samb

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So ive been into rockets since I was 10 or so. But always launched Estes and Quest rockets. I am getting a MadCow Rocketry "lil Goblin hopefully soon. First I read that It can use Reloadable motors but when I search those motors all that comes up is just the repacking stuff. Dont I need a "cannister" for it all to fit inside of? What am I missing. And lastly, the 'lil goblin ive been reading online and a few other sources the body tube is fiberglass but others say its cardboard. Im just looking for clarification.
The "cannister" is usually called a case or reload case, and yes, you will need one if you go with the reloads. Since Madcow lists both single use and reloadable motors in the recommended list for this model, you could go with the single use and defer the cost of the reload case. Like Thirsty mentioned, the single use motors are a good way to start with composite propellent.
That said, reloads are another step in the journey. The Madcow lil' Goblin lists 3 : E16W-4, E23T-5, F40W-7. Aerotech makes alot of different cases for alot of different motors so you need to get the right case for the right motor. There are several places on the web to get this info and my favorite is the Aerotech Master Motor Matrix:

Aerotech motor matrix

At first glance, it's alot. On second glance, it's alot ! :) It has everything you need to know about an Aerotech motor in one convenient place. The motors that you're looking for are under the 29mm Model Rocket RMS Reloadable subcategory. Reading across tells you that these need the RMS-29/40-120 case.

There are two ways to learn how to use the reload system. Youtube video:

Apogee video - How to assemble a reload using the RMS 29/40-120 case

Or, my favorite, find a local club and get a hands-on demo.

Hope this helps.
 

CrazyModelGuy

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thank you for all the great input. I definitely have my reading and research to do. And when I finally get the 'lil goblin built I will likely use single use at first just to get accustomed to flying it. But right now I have an Estes Hiflier and Epic 2 (2 stage) to build.
 

gldknght

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CrazyModelGuy

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Thank you again for all the input. I feel a tad idiotic not knowing what some of these "impulse" things mean. Im used to estes rockets. LOL
 

mtnmanak

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Thank you again for all the input. I feel a tad idiotic not knowing what some of these "impulse" things mean. Im used to estes rockets. LOL
Impulse is the letter rating of the motor. It is a classification of the amount of power, with the higher letters being more powerful. Each letter on the chart is twice as powerful as the letter before it, so they scale up quickly. With Estes motors, you are most familiar with the A-E classes.

Impulse is measured in Newton Seconds:

1622499086052.png


Here are a couple links explaining the motor basics:



Also, Apogee has a whole slew of videos to teach you about motors:


And many more.

Best thing to do is pick up a copy of Harry Stine's Handbook of Model Rocketry. It goes into detail about a lot of questions you will have.


Also take a look at Mark Canepa's and Mike Westerfield's books on high power rocketry. They also discuss different motor types.
 

CrazyModelGuy

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Impulse is the letter rating of the motor. It is a classification of the amount of power, with the higher letters being more powerful. Each letter on the chart is twice as powerful as the letter before it, so they scale up quickly. With Estes motors, you are most familiar with the A-E classes.

Impulse is measured in Newton Seconds:

View attachment 466741

Here are a couple links explaining the motor basics:



Also, Apogee has a whole slew of videos to teach you about motors:


And many more.

Best thing to do is pick up a copy of Harry Stine's Handbook of Model Rocketry. It goes into detail about a lot of questions you will have.


Also take a look at Mark Canepa's and Mike Westerfield's books on high power rocketry. They also discuss different motor types.
Thank you. Yeah I knew some of this. But you know being new to something I just wanted to make sure.
 
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