BAR - First project back - Aerotech G Force

skyway2k

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Hello everyone, my name is William. I'm 30 years old. I'll give just a quick background story of how I've gotten here.

I was born and grew up in the Fort Wayne, IN area. I started flying model rockets when I was in the 5th grade (about 1993). I went deep in to the hobby and built many, many rockets. Most of them were Estes rockets. I built and flew up until about the end of high school. By that time, I was building Aerotech kits and using the Hobbyline hardware and reloads. After high school, other interests took hold and I stopped building rockets. ;)

Every now and then, I'd go out with a few friends and we'd launch a few of the rockets I still had. One of the workhorse rockets I still have is the Aerotech Mustang. I must have flown that rocket at least 20 times now. (BTW - for those wondering, it was built completely stock - CA glue and I used the mesh and baffle. Never had a problem with it. I still plan to keep flying it now.)

Fast forward about 12 years... I had been promoted out of Indiana and I now live and work in Mississippi about an hour away from Memphis, TN. I decided that because of the stress of work and being away from home, I needed something to occupy my time away from home, family, and friends. I needed a hobby.

I spent lots of time on this forum, looking around websites like Apogee and Hobbylinc. Wow... so much stuff to read up on and learn that I didn't have access to in the mid-90s. I also found a club up in Memphis I plan to fly with. I got excited again about rockets - thinking back to my favorites as a kid and teen, the Estes Pro Series Patriot Missile, Photon Probe, Black Brant; the NCR Lance Beta; and the Aerotech Astrobee-D, and Mustang. I'd like to rebuild these kits, only this time as a patient adult. I never really worried much about the finish being perfect as a kid. I never primed before painting, or filled the tube spirals. I didn't do a lot of sanding or wood grain filling. These are the things I think that would make a build rewarding and something to take my time on. I'd also like to get in to some upscaling of the old Estes kits I loved, like the Photon Probe.

I decided to order some kits and I went with an Aerotech G Force and Astrobee D, the NCR Lance Delta, and the Pemberton King Kraken (love the look of this rocket!). I was also scouring around the attic of my house back in Indiana and I found my old Interceptor G kit that I never started. I picked it up on clearance at Hobby Lobby back in the late 90's for about $25 or $30 if I remember correctly! So glad I didn't build that kit back then! If anyone reading this has the old Pro Patriot (2066), I am always on the lookout for one. I check eBay daily now.

So - that's about enough of a background. I started building with the G Force first. I hope this isn't too boring for you guys, but I hoped that by sharing this, I'd learn some things from you all and make it an even more fun experience. :)
 

skyway2k

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So - first off, I got all the parts spread out on the table.

IMG_2524.jpg

I had done some planning ahead - especially after learning some things from you all. I decided that since this was a big bird, I didn't want to limit myself to only using the Aerotech 29/40-120 case. I am going to leave out the engine hook and the thrust ring. I am going to initially fly it with the cooling mesh, but I can always remove it later and add the Nomex blanket for the chute.

I bought an Aeropack retainer from Apogee for motor retention.
 

JordanT

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Welcome to the asylum!

The G-force is a nice kit. This time, though, leave out the engine hook and let the engine mount tube stick out the back a bit, and get an Estes engine retainer. If you have a vendor that comes to your club that sells CTI, go get a Pro29 case (I'd suggest 4 grain to start) and get ready to really have some fun...
 

skyway2k

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Inspecting some of the components of the kit, I was not too impressed with the fin molds and the tube coupler.

On each fin, there's a spot at the root in the middle of the fin where I'm guessing the plastic was injected in to the mold? It leaves a very ugly crater. This will surely need some love and attention to make it look smooth.

IMG_2526.jpg

Also, after reading on the forum about the nightmares and problems with failed separations in flight and the poor fitting coupler, I turned my attention there before even building. Looking at the coupler out of the box, it had a crease in it and was pretty thin. It definitely would not fit in the airframe tube during a dry fit.

IMG_2528.jpg

It's hard to see the crease in the photo, but you can see the out of round shape at the end of the coupler. I decided that since the crease only went about half way up the coupler, this end would get shoved in to the upper airframe and glued. I also took the time to remove a layer of paper from the coupler so it would fit satisfactorily.

Being that the fins don't extend below the body tube, I was afraid of hard landings killing the bottom of tubing, so I cut 1" off the tube coupler (it's 6" long) and I set it aside for later to reinforce the bottom of the body tube.
 

JordanT

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Reinforcement is good if you expect a hard surface impact. I've got one that needs a minor repair after hitting asphalt.
 

skyway2k

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The other thing I didn't really like was that the fin tangs were not in alignment with the fin. They were coming off the fins at an angle.

IMG_2527.jpg

However, once test fitted, the fins came out of the airframe straight, so I didn't worry about it.
 

skyway2k

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I built the motor mount to the instructions, sans engine hook and thrust ring. The other slight modification I made to the construction at this point was to add epoxy fillets to the centering rings and motor mount tube joints. I understand that the thrust and forces during flight are transferred through the parts and how they fit together rather than the adhesive, but I wasn't quite sure if that design was good or meant to handle flights under H power and I figured... what the heck.

IMG_2529.jpg
 

skyway2k

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I had put off this chore for a while.... and I figured it was time to learn. I went to Wally World and bought some Bondo Spot Putty to fill the tube spirals. I just used my finger to work it in to the spiral. I tried to scrape off the excess using a razor blade perpendicular to the tube, but it ended up taking the majority of the putty out of the groove as well. So, more sanding it is, I guess. If there's a better technique, let me know. :)

IMG_2530.jpg

This was the first time I've ever done this on a rocket. I was really striving for a smooth cylinder for the airframe. I wanted to never see those spirals on a rocket ever again.
 

86mustang408w

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My stories about the same as yours. And I hope to get my Gforce build on the way shortly. As for now I'm working on a Pro Leviathan/Mega Der Red Max and am doing some sort of a scratch build between a Big Bertha/Super BB. Welcome back good luck with your build!
 

skyway2k

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Next up was installing the motor mount assembly in the lower tube. I did this with 5-minute epoxy on the forward centering ring to give me time to get the location set right by snapping a fin in to the FinLok rings. Then I used some CA on the mid centering ring to the body tube to lock it in place. I pulled out the fin and flipped the tube around and set it right side up so the epoxy would settle on to the top ring.

I spent some time to fill the nasty mold marks on the fins with spot putty and sanded it smooth after it dried.

Then it was time to attach the fins. I used CA on the fin tangs that snap in the locks and also on the root edges of the fins. After they were installed, I noticed there was a sizable gap between the root and the body tube. I guess this wasn't going to be much of a problem as I planned to add epoxy fillets. However, for anyone building it to the plans, they don't mention fillets and this would leave an ugly joint.

IMG_2539.jpg

I used the masking tape method for the fillets, which I learned on this forum. Thanks! :)

IMG_2540.jpg
 

skyway2k

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People mentioned not gluing the nose cone to the upper body tube and using plastic rivets or securing it with shock cord. I decided that since the nose cone is ugly and of poor quality in my opinion... I decided to glue it in and use putty to hide the joint. When you look at the nose cone head on, it's not round. It's more of an oval as it gets sharper towards the mold marks and flatter 90 degrees from the mold lines. Plus, the nose was pretty flimsy. So, that's why I didn't mind gluing it in. I couldn't think of a reason I'd ever want to use it in the future for something else.

I just used a thin application of 5-minute epoxy on the inside of the tube and slid the nose cone in twisting it as I went. I tried to find a spot that it would blend the best with the tube. After the epoxy set, I used some spot putty on the joint.

IMG_2541.jpg
 

skyway2k

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After sanding the bondo at the nose cone and I was satisfied with the surface, it was almost ready for primer.

I tested the Aeropack retainer on the motor mount tube. It looks like I ordered the wrong one. I ordered the smallest of the three 29mm retainers. It looks like if I would have spent a little more time reading descriptions, it said the middle of the three would have been the right one with a little sanding. The largest leaves a gap.

So - after lots of sanding on the end of the tube with 80 grit, the retainer fits snugly. I removed the retainer and masked off the end of the tube for the JB Weld.

Took the rocket to my paint booth..... the back yard. :lol: Sprayed a nice coat of primer, sanded, primer, sanded.... and I was left with this:

IMG_2548.jpg

I was pretty satisfied that the rocket was ready for paint at this point.
 

skyway2k

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The next dilemma was paint. Sure, the gloss black was the easy part. However, the sea foam green was a little harder. Apparently, this color from Krylon is no longer available. I started doing some research online looking for a substitute. I finally got frustrated to the point where I just headed down to the local Home Depot and started up and down the spray bomb aisle.

I settled on some Rustoleum American Accents Aqua (#223610).

I went to work cutting out the decals. I'm still trying to build up my "shop" supplies and I don't have a metal straightedge yet. So, I used a substitute...

IMG_2573.jpg

It looks like on the artwork of the rocket, the transition between the black and green / aqua / whatever color that is happens further up the airframe than the break point. However, the instructions just say to paint the lower section black and the upper section the sea foam green. This is what I decided to do to make things easier. And I cut the main decal in the location I thought was close to where the color transition happens in the artwork.

I then cut out the G Force emblems for the fins.

IMG_2574.jpg
 

skyway2k

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The final product:

IMG_2581.jpg

It was hard to get a good picture inside.

A few impressions... I hate the decals Aerotech provides for this kit. I was thinking that the yellow would "pop" more than it did after looking at the decal sheet. It seems like the decal material is more of a translucent material. Once peeled off the packing and applied to the black paint, the yellow loses a lot a of its brightness. Very disappointing.

What would have been better to do about that given the decals that we have to work with from Aerotech?

I then sprayed a few coats of clear and removed the masking from the motor mount tube. I mixed up some JB Weld and attached the Aeropack retainer. This bird was all set to fly on December 15th, but the weather didn't cooperate. :cry: I guess it will have to wait until January.

Builds up next: NCR Lance Delta (already done) and old NCR Interceptor G (in process).
 

skyway2k

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I just may do that, thank you!

I hear there's high power flights in Winchester, also?
 

skyway2k

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Here's how it turned out...

Second launch here on a G64-4W. First launch was on a G76-4G but a friend recorded the video and I don't have it yet. Two perfect flights today, never even a hint of trouble at separation. Fun rocket!

[video=youtube;bGQb-4fdqQ8]https://www.youtube.com/watch?v=bGQb-4fdqQ8[/video]
 

AfterBurners

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You did a great job on your G-FORCE. I just started mine today and I agree with you on the fins and the way some things fit. I really like that color scheme you used. I love the blue!! It's too bad the decal don't pop like they should...I might leave mine off or have Mark @ Stickershock make some up for me.

So you just used the stock recovery system? It seems to work pretty well. I was going to upgrade mine and get a bigger chute.
 

skyway2k

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Yeah, I used the stock recovery system as per the instructions. The only thing you have to be really careful of is the fit of the tube coupler at the separation point. Out of the box, it was downright tight. I had to peel off a layer of the paper on the outside for it to even start to go in the tube. To get a good fit, all the white colored paper was peeled off and I was down to the brown. Just make sure it slides alright.

Also - I went with the included amount of BP in the reload kit - and it separated fine both times. I don't think you need extra BP to separate with a G reload. There really isn't THAT much volume you're trying to pressurize. There's only about 4 inches in the bottom end, and another 4 inches in the top end, plus the length of the motor tube.
 

skyway2k

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I really like that color scheme you used. I love the blue!!

I forgot to mention, if you like that blue color, I got it at Home Depot. It's Rustoleum Painter's Touch - Satin Aqua. It was the closest thing I could readily find to that Sea Foam Green color Aerotech used.
 

jsargevt

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Nice rocket, nice flight.

A tip for the cameraperson: Looks like an iPhone or similar is being used. Hold it "landscape" style" rather than "portrait" style and it will fill the YouTube box rather than being 1/3 of the viewing area. It can be a little more challenging to keep in the frame, but once you get the hang of it you might prefer the output online.

Unless, of course you like just using the middle 1/3 of the youtube frame. Then carry on....
 

skyway2k

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Nice rocket, nice flight.

A tip for the cameraperson: Looks like an iPhone or similar is being used. Hold it "landscape" style" rather than "portrait" style and it will fill the YouTube box rather than being 1/3 of the viewing area. It can be a little more challenging to keep in the frame, but once you get the hang of it you might prefer the output online.

Unless, of course you like just using the middle 1/3 of the youtube frame. Then carry on....


Yes, it was an iPhone. :) Thanks for the tip!
 

JP Morgan

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The final product:

View attachment 109218

It was hard to get a good picture inside.

A few impressions... I hate the decals Aerotech provides for this kit. I was thinking that the yellow would "pop" more than it did after looking at the decal sheet. It seems like the decal material is more of a translucent material. Once peeled off the packing and applied to the black paint, the yellow loses a lot a of its brightness. Very disappointing.

What would have been better to do about that given the decals that we have to work with from Aerotech?

I then sprayed a few coats of clear and removed the masking from the motor mount tube. I mixed up some JB Weld and attached the Aeropack retainer. This bird was all set to fly on December 15th, but the weather didn't cooperate. :cry: I guess it will have to wait until January.

Builds up next: NCR Lance Delta (already done) and old NCR Interceptor G (in process).

Great looking colors William!
Yup, I've got to have one...

JP
 

skyway2k

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I forgot to add pictures of the first launch. They are much better than my pictures I took in my house. Here goes:

On the pad before the first launch... builder was holding his breath.
IMG_0270.jpg

First launch on a G76 Mojave Green. Turns out... not my favorite propellent. I thought it would be cool, but it was just okay.
IMG_0278.jpg

Second launch of the day on a G64 White Lightning. My favorite. Big flame and lots of smoke.
IMG_0465.jpg
 

samb

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I'm impressed by/jealous of your launch pics; a skill I'm struggling with. What equipment, tip/tricks can you share ?
 
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86mustang408w

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How far did it go from the launch site? I'm still worried about launching mine in the space I have. Looked good for you anyways.
 

skyway2k

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I'm impressed by/jealous of your launch pics; a skill I'm struggling with. What equipment, tip/tricks can you share ?

Sorry, I didn't take the pictures. Roger Cotton of Mid South Rocket Society took the photos. From the looks of it, he had a really nice camera.
 

skyway2k

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How far did it go from the launch site? I'm still worried about launching mine in the space I have. Looked good for you anyways.

It didn't go far at all. I'd say maybe 1,000 feet down range or so. It comes down pretty quickly on the stock parachute. No damage at all though, just a paint chip on one fin corner.
 
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