Aerotech G-Force Build

[dgreger]

This kit arrive Friday afternoon, I picked it up from Hobbylinc on sale for $62. I'm making quite a few modifications to the build. Mainly foregoing the Labyrinth ejection system and using tubular nylon with a nomex cover and blanket. I am a little disappointed at the flimsiness of the NC that came with the kit, it is very thin and easily mis-shaped. if its a hot day on the flight line, this one will need to be kept in the shade until launch. I'll probably use it until I decide on a suitable replacement. Will have to be careful with it once its painted! I am also not going with the stock paint job. This one is going to play off the G-Force name, but I'm going to keep the final scheme a secret til its done. I will be sending Mark an email at Stickershock!

 

[dgreger]

Also going with 1/4 ply CRs vice the ones that came with the kit since I'm not using the motor hook in favor of an Estes 29mm motor retainer.
This is the forward ring drilled for the eyebolt, and the entire MMT epoxied after making all the measurements for the retainer so it sits flush with the aft end of the BT. I figured with the fin-lock system there was no need to do internal fillets, but I will smear some epoxy on them when I install them.

 

[dgreger]

Also switching out the launch lugs in favor of rail buttons. Can't remember who suggested it but I left the small strip of cardboard in the BT and drilled the hole for the rail button, then I'll fill it over and smooth it out when I fill the spirals. You can see the Patriot airframe and Nosecone in the background that I am also doing a build thread on.

 

[dgreger]

MMT complete and epoxied in place with retainer, I also cut and epoxied a length of tube coupler into the aft BT to give some added strength in case of any hard landings. As an after thought I could have added another thin CR to the MMT but the retainer was already glued in.

 

[dgreger]

Spirals filled and drying. I have a crap ton of sanding to do since I am building this alongside my 4" Patriot!

 

[qquake2k]

MMT complete and epoxied in place with retainer, I also cut and epoxied a length of tube coupler into the aft BT to give some added strength in case of any hard landings. As an after thought I could have added another thin CR to the MMT but the retainer was already glued in.

That's odd that Aerotech would design the aft centering ring in that far. Looks like it would be prone to damage, even with your strengthening.

 

[dgreger]

That's odd that Aerotech would design the aft centering ring in that far. Looks like it would be prone to damage, even with your strengthening.

It is, but remember there is about 3+ inches behind the trailing edge of the fins, and the aft CR is against the TTW tangs/finlock ring. Hopefully with the 42" chute it should come down fairly well and slow. Only fear I have is that nose cone. It flexes almost by gripping it hard enough to pick it up. I am contemplating filling it with foam. have to see what RockSim says with the added weight. I think it should balance out since I added weight to the MMT with the heavier CRs.

If I could get another MDRM NC from Estes I would use that. Or I might just swap it between the two rockets.

 

[qquake2k]

It is, but remember there is about 3+ inches behind the trailing edge of the fins, and the aft CR is against the TTW tangs/finlock ring. Hopefully with the 42" chute it should come down fairly well and slow. Only fear I have is that nose cone. It flexes almost by gripping it hard enough to pick it up. I am contemplating filling it with foam. have to see what RockSim says with the added weight. I think it should balance out since I added weight to the MMT with the heavier CRs.

If I could get another MDRM NC from Estes I would use that. Or I might just swap it between the two rockets.

Unless it comes in ballistic, I wouldn't worry about the nose cone. If it does come in ballistic, all bets are off anyway. I've used quite a few Mercury Engineering nose cones, which are thinner than LOC cones. Haven't had any problems.

 

[neond7]

MMT complete and epoxied in place with retainer, I also cut and epoxied a length of tube coupler into the aft BT to give some added strength in case of any hard landings. As an after thought I could have added another thin CR to the MMT but the retainer was already glued in.

Great build thread, if I ever build another G-Force to replace my original one (R.I.P) I'll use some of these modifications. The tail on mine did take lots of beatings. Because of that, I did use a cut down section of body tube to reinforce the tail of the Mad Cow Frenzy I built last month.

If I do build another G-Force (very likely), I will coat the coupler and inside of the body tubes with CA and sand them well so they will slide more consistently. The coupler had stuck and it came in ballistic on its last flight, the coupler gets pretty worn after about two dozen flights. I'll also try the Estes screw on ratainer, I use Aeropack's so I like the screw on design.

One tip, if you mix a filler with your epoxy, it won't run. Mix some colloidal silica in with it, and then use the back of a plastic spoon and you can really make some nice internal fillets around the centering ring/body tube connection.

 

[qquake2k]

On my zipperless builds, I flood the coupler with CA then mount it on the lathe to sand and polish it.

https://www.rocketryforum.com/showthread.php?37489-Upscale-Alpha-III&p=349134#post349134

 

[fyrwrxz]

Also switching out the launch lugs in favor of rail buttons. Can't remember who suggested it but I left the small strip of cardboard in the BT and drilled the hole for the rail button, then I'll fill it over and smooth it out when I fill the spirals. You can see the Patriot airframe and Nosecone in the background that I am also doing a build thread on.

FWIW- the cardboard 'plug' is die cut/punched to be removed for fitting the plastic do-hickey Aertech calls a 'lug'. I would re-enforce that area if you drilled thru it for a button. Also- I used a section of coupler on the bottom to double up the body tube as it does get 'crunched' on landing. Flooded the inside with thin CA after bonding it to the B/T for added rigidity. just my 2 cents. I threw a removable tailcone on mine and call it the "Blackout" Good flights to ya!

 

[dgreger]

Thanks for all the tips guys, I taped the fins to make the epoxy fillets last nite, havent done it yet. And I did reinforce where the rail buttons are installed, I used the standard 1010 buttons from Madcow ordered from Apogee, and epoxied the weld nut backing to the inside of the BT.
The tube coupler definitely needs some work, the edges on Both ends are chewed up so I might be sawing off about a 1/4" to clean them up, then as Quake said, flood it with thin CA. It will definitely need some serious sanding to get it to slide free enough.

 

[dgreger]

As an after thought for anyone building or planning on building this rocket, there is always the option of cutting one or two inches of the BT, and MMT thus shortening the damage prone tail section. It would however add to the possibilty of Fin damage but it does seem these things fly fairly well and recover...........
So I guess its a toss up

 

[neond7]

Ok, this build thread got me missing having a G-Force in my fleet, so I ordered one last Friday from Hobbylinc. They had a good $66 sale that I couldn't pass up. It shipped Monday, I'm hoping it will be there when I get home from work.

I'll definitely be using an Estes screw on motor retainer and Aerotech rail buttons. Hopefully I'll have a section of 4" body tube laying around that I can cut down to reinforce the tail end with. I didn't have any 4" centering rings with 29mm holes, so I'll stick with the big fiber CR's, they seem to work ok.

Instead of CA, I plan on using Aeropoxy 6209 structural to internally connect the fins to the fin tab keepers. Because of the width of the plastic base of the fins, I don't think I'll be using external fillets, I don't think it would add anything to the plastic fins.

I'm sure the kids at the local park will enjoy seeing me launch there again, it usually draws a pretty good crowd of curious onlookers.........

 

[dgreger]

Ok, this build thread got me missing having a G-Force in my fleet, so I ordered one last Friday from Hobbylinc. They had a good $66 sale that I couldn't pass up. It shipped Monday, I'm hoping it will be there when I get home from work.

Thats the same sale I hit when I bought mine, I'm still a little concerned with the nosecone as to how easily you can squish it. Not so much for it not holding up to flight but not cracking the paint when handling it.

 

[dgreger]

Ok, fillets are done and its in primer, still some sanding and touching up to do but hopefully get it into final color this weekend if the weather holds out.

 

[dgreger]

A little out of order, but sustainer/fin can primered and ready for first sanding

 

[neond7]

Looking great! I was a little disappointed mine didn't show up yesterday, maybe it will arrive today.

The wife is out of town this weekend, so I'll get plenty of free build time. :dark: Just wish it wasn't so hot in the garage!!! I'm still finishing up my LOC Magnum and LOC Hyperloc 835, the Aeropoxy light filler showed up a few days ago so I can get back to work on those builds. Nothing like having three rockets in work at the same time..... Oh, what?? ADHD? Me?? LETS GO RIDE OUR BIKES!! Oh, a squirrel. I saw a rock. Hi.

 

[qquake2k]

Oh, what?? ADHD? Me?? LETS GO RIDE OUR BIKES!! Oh, a squirrel. I saw a rock. Hi.

:lol:

 

[46u]

I am working on the same model right now. Nice job. I have had my kit for about 7 years and just now getting around to it.

 

[TheSamurai]

I took out the labrynth from mine as well. Going with a nomex blanket instead. Haven't flown it yet. Still finishing up on the paint and then all I have left to do is attach the elastic shock cord and Kevlar. I'm using about 2 feet of Kevlar along with the elastic. And I also went with 1/4 inch eye bolts instead of the tiny ones that it comes with and using quick links as well.

 

[46u]

I took out the labrynth from mine as well. Going with a nomex blanket instead. Haven't flown it yet. Still finishing up on the paint and then all I have left to do is attach the elastic shock cord and Kevlar. I'm using about 2 feet of Kevlar along with the elastic. And I also went with 1/4 inch eye bolts instead of the tiny ones that it comes with and using quick links as well.

I am using the pieces in the kit is there a reason not to?
Thanks
Jeff

 

[TheSamurai]

I'm sure the kit will work just fine as it is. I'm just being extra pre-cautionary because it is going to be my L1 and I am making this thing solid.

 

[46u]

Thanks,
Jeff

 

[AfterBurners]

Its a good kit for the money. I had issues with warped fins, but AT replaced them. The tube coupler needs a layer peeled back to get it to fit. I bought and extra one to reinforce the aft section of the body tube. Yeah it was a PITA sanding that thing and painting it. I ordered a SUMO which I'm looking forward to building.

 

[46u]

I got my kit about 7 years ago and just now putting it together. I have been messing with rockets off and on for over 44 years. I sure wish I had all I throw away over the years.
Thanks
Jeff

 

[Nathan]

I am using the pieces in the kit is there a reason not to?
Thanks
Jeff

The labrynth ejection baffle works as advertised. Others on this forum have said that after many flights it can get clogged up with carbon residue which can cause it to catch on fire. Also, make sure that the red ejection charge caps don't get stuck in the mesh.

If I ever build another Aerotech kit I'll probably not use the labrynth baffle either. Dog barf is cheap, effective, and idiot-proof.

 

[46u]

Have a PML I am all most done with it is much better made. It is not as big. I have never launch a mid rocket yet. I have to buy or make a launch pad for it.
Thanks
Jeff

 

[dgreger]

Well, here it is on the left next to L1 Cert Patriot. Both ready for paint. At some point you just have to put the sandpaper down and slowly back away! I mean that little imperfection won't be seen when its on the pad or 2k feet up!

 

[qquake2k]

Well, here it is on the left next to L1 Cert Patriot. Both ready for paint. At some point you just have to put the sandpaper down and slowly back away! I mean that little imperfection won't be seen when its on the pad or 2k feet up!

They both look great! I never worry about minor imperfections. I go for 50ft paint jobs.