G-FORCE Build

AfterBurners

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Some how I was persuaded to do a build thread on my G-FORCE so why not. Anyway first set of pictures of all the parts laid out. I already have a few ideas of how I'm going to build this. Since this will be my Level 1 rocket I'm debating about using epoxy to apply fillets to reinforce the fins. I might use epoxy clay since it's easy to work with and I could do all the fins at once without having to wait. For those of you who used it, you know how hard it sets up. It's like concrete after it dries 24 hrs.

The quality of the fins are ok at best, but they could use some work to get rid of the spots where they molded them. I want to build it strong enough, but not bullet proof and keep it somewhat light.

I might go with an I200W-10 for my Level 1 flight.

I'll be eliminating the thrust ring and mesh and going with an Aeropack retainer.

011.jpg 012.jpg 013.jpg 014.jpg 015.jpg
 

fyrwrxz

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Good show! Check your all up and you may have to adjust the delay on that I200. Have fun!
 

fyrwrxz

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I'll be joining ROC as I get closer to completing this build. I'll get my Level 1 with them.
Gimme a shout when you're ready- i need a road trip. Missed two really nice local launches due to wife's injuries since November.
 

n3tjm

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Make sure you bond the entire root edge of the fin to the body tube if you plan to fly that on an I200. Most I ever flown my H-Force on was a H180. Was scared to do anything more with it.

I'm not sure if it was a bad luck of the draw, but the last couple Aerotech kits I built seemed to be less quality than the ones I built back in the 90's. The tab on the motor hooks snap off easily, and the parachutes are a frayed mess... still useable... but feels cheap.
 

Scott Evil

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Secure your fins to the motor mount, the external fillets are more or less a cosmetic fulcrum (pivot point). Dry fit/snap it together and wiggle the fin tips around, you'll see what I mean.

Maybe invest a couple dollars on an extra centering ring for the top of the motor mount. What this does is seal off unused airspace/volume and direct the charge forward where you want it.

Luck to your L1, you'll get er dun!

-S
 

JP Morgan

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Watching this one closely!
I just like the 4" body rockets and this one being 29mm makes it easier
on the pocket book too.
Thanks for taking the time to post your build.

JP
 

chadrog

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Maybe invest a couple dollars on an extra centering ring for the top of the motor mount. What this does is seal off unused airspace/volume and direct the charge forward where you want it.

The kit should have a third centering ring included for that, you got gyped if it didn't.
 

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With an I220 in there, light in weight is not the issue. I would suggest taking the coupler and gluing to the top of the find can and reinforcing the inside with something so that it is zipper less. I frequently take heavy card stock and glue that to the inside, to make the walls thicker. You can take screws to secure the nose cone, and do not forget the vent holes, or it might come apart on the way up. I might also ditch the plastic launch lugs and put some wood reinforcement on the inside of the fin can so I can put rail guides on it. Have you simmed it out to determine the altitude you will reach? You might consider a tracker or a transmitter for direction finding, and you might consider dual deploy. If it is going over about 3000 feet, I would certainly consider that. You might want to figure out a way to reduce the volume of the tube that has to be pressurized to help insure the ejection charge will deploy the chute(s). I can check the simms when I get home tonight and test that motor is you want. Just let me know. I am not trying to tell you how to build your bird. I am merely suggesting some additional thoughts if you have not considered them. I do hope this helps. BEAR
 

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I was curious about the i200 so I ran a sim. it says 2200' but that is before adding weight to the nose to make it stable, which will be necessary.

edit:

4 oz of nose weight didn't change the altitude much and is stable.
 

BEAR

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I was curious about the i200 so I ran a sim. it says 2200' but that is before adding weight to the nose to make it stable, which will be necessary.

edit:

4 oz of nose weight didn't change the altitude much and is stable.

I am a bit confused. I just ran RockSim on a stock G-Force using a AT I200W; I came up with about the same altitude, but it showed it was stable with a margin of 1.68. Now when I did it with a CTI I243, also stable, I came up with an altitude of 3108. Maybe my simulation is incorrect, or my masses are wrong.

Since I built mine to accept 38mm 6G-XL, on a CTI "J", it remains subsonic and it sims out to 6300'. I think I will have to fly it on dual deploy, either way just to keep it from drifting a few miles.
 

Derek

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I had to fiddle with the cg in the openrocket model to match my finished rocket, however I've never gotten close to that stability number. with 2 oz of nose weight in mine, a h90 has a stability of 1.22. with the i200, it was .9 something.
 

AfterBurners

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Thanks for the great suggestions guys and I will definitely take all of them into consideration. At this point I'm not sure how much I plan on investing in this project with all the changes in upgrades. I'll start on it this week and let you know of my progress. I want to build a good solid rocket, but within a reasonable budget so I need to think through some of this before I get started.
 

BEAR

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Here are a few pictures of my G-Force in primer with the 38mm long motor mount in it, piano wire shock cord anchor, long motor hook and zipperless coupler. The long white tube is my extension tube, so that I can make it dual deploy and have plenty of room.
G-Force Stock in Primer with extension next to it (1).jpg G-Force Stock in Primer with stock extension next to it.jpg

G-Force Stock in Primer, bottom showing 38mm motor mount w-long motor hook and piano wire anchor.jpg G-Force Stock in Primer, Fin Can by itself.jpg

G-Force Stock in Primer, top of fin can with zipperless coupler, top bulkhead and top of motor h.jpg
 

86mustang408w

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So what's the benefit of the Aeropack retainer(not even sure what it is..) over the mesh? I just bought a Gforce myself, so far its the biggest rocket I will have flown. I'm only launching on a G right now, I'm not so sure I really can go bigger around here.
 

Derek

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they are two separate things. motor retainers (like the aeropack) keep the motor in the rocket when the ejection charge fires. the mesh is used to protect the recovery gear from the hot ejection gasses.

the aeropack retainers are nice, but pricey. I put a $5 estes retainer on my g force and it does the same thing, but is way cheaper and weighs less.
 

AfterBurners

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So what's the benefit of the Aeropack retainer(not even sure what it is..) over the mesh? I just bought a Gforce myself, so far its the biggest rocket I will have flown. I'm only launching on a G right now, I'm not so sure I really can go bigger around here.

The retainer has nothing to do with the mesh it's a method of securely the rocket motor instead of using the standard engine hook that comes with the kit.
 

AfterBurners

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they are two separate things. motor retainers (like the aeropack) keep the motor in the rocket when the ejection charge fires. the mesh is used to protect the recovery gear from the hot ejection gasses.

the aeropack retainers are nice, but pricey. I put a $5 estes retainer on my g force and it does the same thing, but is way cheaper and weighs less.

I never actually weighed each one, but I would say that there's not much difference between the two. You are though they are pricey
 

86mustang408w

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The retainer has nothing to do with the mesh it's a method of securely the rocket motor instead of using the standard engine hook that comes with the kit.

Oh, ok. So what do you use then to protect the recovery equiptment(bare with me I'm new to these rockets). Are you using rail buttons on yours? Thanks for the help, Michael B.
 

Derek

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I use a little bit of dog barf (cellulose insulation) and a kevlar blanket. I put the launch lugs and rail buttons on mire, but have only used a rail to launch it.
 

AfterBurners

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Oh, ok. So what do you use then to protect the recovery equiptment(bare with me I'm new to these rockets). Are you using rail buttons on yours? Thanks for the help, Michael B.

You can used what is call a "NOMEX" blanket. You would wrap the chute in the blanket like a burrito making sure to completely cover it and then pack it into the airframe. The blanket is attached to the rocket by threading the shock cord through a slit in the blanket. The Nomex blanket is made from fire resistant material to protect the chute from any hot burning particles of the motor ejection charge. They have different size blanket for different size airframes. They also make shock cord protectors too...

Visit Topflight's website

https://topflightrecoveryllc.homestead.com/index.html

Pictures below

IMG_1513.jpg IMG_1514.jpg
 

Atlasboy

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I put an H165 in mine with no issues. I also have a H250 that I'm going to give a whirl in the next month or so. I just used some dog barf. Worked fine.
 

86mustang408w

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You can used what is call a "NOMEX" blanket. You would wrap the chute in the blanket like a burrito making sure to completely cover it and then pack it into the airframe. The blanket is attached to the rocket by threading the shock cord through a slit in the blanket. The Nomex blanket is made from fire resistant material to protect the chute from any hot burning particles of the motor ejection charge. They have different size blanket for different size airframes. They also make shock cord protectors too...

Visit Topflight's website

https://topflightrecoveryllc.homestead.com/index.html

Pictures below

View attachment 114443 View attachment 114444

Ok...Does the included mesh "system" that comes with the kit fail often? I'm just wondering if I should make a few upgrades. Its not a super expensive rocket, but I don't wanna add it to a scrap pile either. Thanks for the help, and good luck with the launch. What color scheme you looking to do? Mike B.
 

AfterBurners

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I've heard mix comments about the mesh. It does work, but you need to take it out frequently and clean it or replace it when necessary. For me the Nomex blanet is a simple and inexpensive upgrade. I also don't like the chute that comes with the kit...has a cheap feel to it.
 

86mustang408w

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I may look into what you did, I agree the chute does seem a bit cheap. What all comes the the Aeropack retainer? Do you have a link you mind sharing?
 

Rex R

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I weighed an aeropack & an estes retainer...as I recall the aeropack was 0.2g heavier(iirc 13.8g vs 14g) the Estes retainer does take up a bit more space though.
rex
 

AfterBurners

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I may look into what you did, I agree the chute does seem a bit cheap. What all comes the the Aeropack retainer? Do you have a link you mind sharing?

Check out their website

https://aeropack.net/motorretainers.asp

They have different retainers for different size tubes and materials. Make sure you buy the proper one or ask anyone here for help.
 
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