Aeroforce G-Force 4

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1974_Trident

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I am planning my first BIG rocket. My Aerotech G-Force 4 should arrive sometime this week along with a Big Bertha, a Der Red Max and a pair of Alphas all for the kids.

I am brand new to re-loadable motors but I have experience handling things that go, "boom." I am considering the Aerotech (or Rouse Tech) 29/40-120 hardware and an assortment of G impulse loads; G64-4, G71-4, G76-4 and I even see possibilities with a G53-5 which seems like it would give a nice slow liftoff for my viewing pleasure. I may even get a few F loads.

For the near future I will be launching at the local school athletic field so I want to keep altitude within reason. Are there any factors other than field size which would limit my target altitude? My New York Sectional shows my launch area is just outside DXR's class D airspace but within Class E airspace with a 700 foot floor. Does this mean I need to keep my flights below 700 feet?

I took a quick look at pictures of kit components of the G-Force 4 and immediately I want to use an engine retainer other than the flimsy little metal hook. I've read a lot on these forums which advocates simply friction retaining my engine. On the Apogee website I saw a nifty looking little engine retainer, the AeroPack, which looks like a really secure device. Has anybody here used one? I see that the G-Force kit also comes with a pot scrubber which promises to cool off ejection charge gasses. I've read nothing favorable about this pot scrubber thingy here and in fact I am under the impression that this device is best left out and its function replaced with wadding. Am I thinking along the right lines? Will I have to add additional protection for the shock cord i.e. Nomex or Kevlar sleeve for the few feet closest to the bulkhead? While I expect to find out for sure when the kit arrives I would like to know if I can build the rocket with a 38mm engine tube and use adapter rings for a 29mm motor. I would like to be able to fly big motors when I am ready although I would be completely content to stick with the impulses available in 29mm format.
 
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H_Rocket

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Aeropack retainers are some of the nicest ones there are. There are equivalents that cost a bit less (HAMR by PML and Lock-N-Load) by Wildman). Just make sure you have enough motor tube sticking out to affix it. You can also use the Slimline by Giant Leap.

BTW, the motor hook on an Aerotech kit is many things, and flimsy is not one of them. In fact I often curse at them for being so stiff. That said, I would rather not use them as they also rust.
 

Initiator001

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The motor hook on the AeroTech G-Force kit works fine. As with all motor hooks, I do apply a wrap of masking tape around the hook and motor after motor installation.

The baffle system on the G-Force (and all AeroTech kits) works fine if assembled and used correctly.

I have only flown my G-Force on 'G' motors, not sure if an 'F' would work/be safe.

I modified my G-Force to use two parachutes to bring the upper and lower sections of the rocket down separately. I, also, cut a piece of tube coupler and glued it into the aft end of the rocket up to the aft centering ring. This doubled the thickness of the body tube as the model lands on the tube, not the fins.

I think you'll enjoy flying the G-Force.
 
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The 29/40-120 cases are great. You will love the load available for it. I fly that case more then anything. I just bought a second case, just so I can fly more often without cleaning. It's a great motor.

If you can build the rocket with a 38mm MMT do it!!! :2: There are a lot of motors available in 29mm, but there are a lot more available when you add 38mm to that. I'm not sure the Aerotech fin mounting will hold up to the larger 38mm motors, but it would be fun to find the limit.

One thing about the G-Force when you fly it on Hobbyline motors. The 4" tube has a lot of volume and sometimes the ejection charge is a little weak for that big of tube. The baffle doesn't help. I've seen several rockets pop the nose cone but not the chute and others where I've heard the ejection charge but the nose cone didn't come off. It ended up about 16" long. An extra 1/4 gram of FFFFg powder in the ejection charge makes it much more of a sure thing.
 

dpower

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I've had no issues with the mesh baffle. I've heard it can get clogged, but I haven't experienced that. After years & many flights, it can eventually rust away. In either case, it can be removed and replaced with 3M or Chore-Boy pads from a hardware store.
 

1974_Trident

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Thank you, everybody, for your input so far. The kit arrived yesterday. After inspection of the components and reading the destructions I have decided that the pot scrubber will stay. Since I am using the Aeropack threaded motor retainer I will not have the engine hook or thrust ring. The pot scrubber will be pretty easy to remove for cleaning. I am going to stick with the 29mm mount, there are enough big motors which will fit. When I want to move up to 38mm I will just have to buy another rocket. I don't think that will be all that terrible.

Along with my G-Force came several other kits for my kids; Big Bertha, Der Red Max and a pair of Alphas. We are going to have a big rocket building family get together this weekend!

Pictures to follow.
 
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Sounds like you're going to have a great weekend! :D

Sticking with the 29mm and getting another rocket when you want a 38mm is a great plan. If you're like me, you won't miss the 38mm MMT in the rocket until you get that rocket with the 38mm and fly a few motors in it. They you'll be wishing you could fly those motors in the 29mm rockets you have. I've only flown a couple of 54mm motors in my L2 rocket and already I'm regretting not putting a 75mm MMT in it. Oh well, guess I'll have to build another one too.
 

terryg

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One other mod to consider is to add rail buttons. That way you can fly from both 1/4 inch rods and also from a rail for high power flights. It is a large rocket and the rod whip with the larger high power reloads is significant.
 

1974_Trident

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In regards to rail buttons I looked at a few commercially available rail button kits and they look like nothing more than a couple of washers, a spacer, a screw and a T nut. All stuff I can get at a local hardware store. Since I don't have a launch rail yet, I plan on making my own. How wide is the slot supposed to be? I would like to have a rail which is compatible with commercially available components for rockets I will purchase in the future which may come with a rail button. And I would like my G-Force to be compatible with said rail. Instead of T nuts I may use a piece of 1/8" aluminum flat stock drilled and tapped then sanded to match the contour of the inside of the body tube and epoxied in. How far apart should I mount the rail buttons? A lot of pictures I've seen of rockets with rail buttons show the two buttons mounted about 6" or so apart which seems close to me but I am only used to using waxed paper drinking straw launch lugs which are mounted much further apart when a rocket has two.

Since we are on the subject, Aerotech recommends a 1/4" launch rod at least 36" long. Without trying I can go to Home Depot and get either 36" or 72" rods. Are there any risks or other disadvantages to using a longer than necessary launch rod?
 

Initiator001

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Since we are on the subject, Aerotech recommends a 1/4" launch rod at least 36" long. Without trying I can go to Home Depot and get either 36" or 72" rods. Are there any risks or other disadvantages to using a longer than necessary launch rod?
I flew my G-Force off 5'-6' launch rods.

I would use something longer than 3'.
 
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In regards to rail buttons I looked at a few commercially available rail button kits and they look like nothing more than a couple of washers, a spacer, a screw and a T nut. All stuff I can get at a local hardware store. Since I don't have a launch rail yet, I plan on making my own. How wide is the slot supposed to be? I would like to have a rail which is compatible with commercially available components for rockets I will purchase in the future which may come with a rail button. And I would like my G-Force to be compatible with said rail. Instead of T nuts I may use a piece of 1/8" aluminum flat stock drilled and tapped then sanded to match the contour of the inside of the body tube and epoxied in. How far apart should I mount the rail buttons? A lot of pictures I've seen of rockets with rail buttons show the two buttons mounted about 6" or so apart which seems close to me but I am only used to using waxed paper drinking straw launch lugs which are mounted much further apart when a rocket has two.

Since we are on the subject, Aerotech recommends a 1/4" launch rod at least 36" long. Without trying I can go to Home Depot and get either 36" or 72" rods. Are there any risks or other disadvantages to using a longer than necessary launch rod?
You can try to make your own rail if you want, but I wouldn't bother. Most of us launch our larger rockets at club events and the clubs supply the waiver and launch pads. If you want your own pad, you can get the 1010, or Standard rail from McMaster-Carr or other local vendors. The T-slot is 1/4" wide. The 1515 or Extreme rails have 5/16" wide slots, but you shouldn't need anything that big until you're well into Level 2 rockets.

As for making your own buttons, be aware that some clubs only allow plastic buttons because the metal ones can gouge and wear the rails. You also will have to make sure your homemade buttons fit inside the t-slot. The outside diameter and thickness of the T part is critical to prevent binding. Homemade ones might work great on a homemade rail, but might not work at all when you go to a club launch.
 

1974_Trident

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Anyway, this project has been underway for nearly a week now.

I was delighted to come home and find this nice big box behind the storm door.

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1974_Trident

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I didn't like the wood screw eye that came with the kit. I see this screw eye pulling out of the forward bulkhead. While the wood screw may be secure in the baffle I am more comfortable using machine screw eyes and nuts. Next time I'm putting a nice wide fender washer on the bulkhead.

Taking lessons from another build thread I masked off the body for filleting the fins. The destructions that came with the G-force don't mention filleting but I don't see any harm in overbuilding.

I like the way the epoxy makes its own fillets. All I have to do is position the rocket properly and let gravity do the rest. The epoxy seems to have the ideal consistency for the right length of time. A little bit of sanding will clean up any of my imperfections. This is the first time I've used epoxy for building a rocket and I am now hooked.

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1974_Trident

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While we are here, something has come to my attention and I'm glad now rather than after I've finished painting.

The body tube coupler fit nice and tight into the forward body tube but is way to tight a fit in the rear body tube. In fact there is at least 1mm of interference. I cut a few slits in the end of the coupling tube so it will squeeze down and fit into the rear body tube and even this takes some manhandling. The fit is so tight I an afraid to push the tube all the way together out of fear I might not be able to get them apart. Any suggestions of how I can loosen the fit a little? Can I sand the inside of the rear body tube? Any tried and true tricks of the trade? I am afraid that with such a tight fit the ejection charge may not be enough to deploy the 'chute and the fit may be so tight that the body tube could rupture instead of separate at the coupling.
 

loopy

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Alot of sanding to get the coupler to fit better. Same techniques as with LPR stuff.

Definitely get a 29/40-120 motor. This casing is invaluable for the MPR flyer. The 29/120 casing is another good one with some great G loads.

As for the 38mm stuff - I love my PML Small Endeavour. Awesome design, 38mm. Flies awesome on the same G loads you'd put in the G force, and any H you can throw at it. used it for my level 1, and it was a thing of beauty! I also highly recommend the PML 2" AMRAAM. Perfect mid power rocket.

Rail buttons - look at PML or Newtons 3rd Rocketry for rail buttons. They are insanely cheap, and well worth the money. Flying with clubs is a great way to go with the bigger rockets - they take care of any regulations that need to be dealt with, and the people there can help you with any problems or questions you might have - especially when it comes to building your first reload.

SPeaking of reloads - a 24mm RMS casing is also another must have for the mid power flyer. This casing holds alot of E and F loads that are perfect for things like the Estes Mean Machine, Big Daddy, Prowler...really, any of the larger 24mm kits out there. I build those with a LOC 24mm motor tube (handles the higher heat better), and switch the balsa to basswood, and it's great!
 

terryg

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Aerotech couplers seem to always be too tight. I do not sand them, I just peel of a layer of paper to give an acceptable fit. When glueing in the coupler make sure that is a very easy slide fit. For any glue but epoxy a tight fit will cause it to seize up faster then you would expect and you can get a coupler that is only part way in position. I would not use CA for the coupler (just asking for trouble).
 

1974_Trident

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With regards to the coupling tube; I did use copious amounts of CA to glue it in. I was aware of the potential for it to seize up so I worked really fast. All went as planned. I left the upper and lower body sections coupled over night and that seems to have "Stretched" the fit out a bit, it doesn't seem as tight as it did the day before.

The entire rocket is in primer now and I almost don't want to paint it. It looks quite mean in primer. Maybe stenciling some official looking words or something on it will finish it up. Maybe I will do the black/blue color scheme complete with the included decals. I'll decide when I'm ready to add color.
 

1974_Trident

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So, I decided on color.

For a while I was considering a Cobalt Blue and no other color for the upper half of the rocket. I couldn't find a Cobalt Blue in Krylon so I started to call the auto paint suppliers. In all cases I would need a color code to get a price over the phone and in all cases I was told it would run about $75-100 for a pint!!! You've got to be kidding me! Something about the pigments in Cobalt Blue that makes them so expensive. I am not spending $100 to paint a $95 rocket. Besides I had to drive an hour to the nearest store that carries PPG Duracryl. I already painted the lower half of the rocket in Duracryl Acrylic Lacquer and I wanted a paint for which I would be able to use the same clear coat on the top half of the rocket as on the bottom half. I have a half quart of black Duracryl and Duracryl clear Coat in my garage from when I painted my motorcycle many long years ago.

In short it was becoming to much an exercise in logistics and disposable income to go with Cobalt Blue. I was getting myself ready to settle for a different shade of blue and I was about to go to the hardware store to see what they have. My son pulled into the driveway on his bicycle as I was ready to get into my truck. My son's bike is a very sharp combination of black and Hugger Orange. Something which really appealed to me when I bought his bike a few months ago. I started toying with the idea of painting the front half of the rocket a nice Hugger Orange. I knew the 1970 Pontiac GTO Judge was available in this shade (called Judge Orange). I went online and looked up the paint code for that color on a 1970 Pontiac GTO to bring to an auto paint store.

On our way out we stopped by the local hardware store first just to see what colors they have in stock. There it was in the Ace Hardware store brand of paint (Krylon in the Ace Label for two $$ a can less.) $12 and only fifteen minutes later we were back in my garage.

I have to re-sand a repaint the bottom half of the rocket. I forgot about Duracryl. Re-coat within five hours or after 48 hours. The second coat which I applied after only 20 hours orange peeled. After seeing how well the spray paint handled and finished I am dissuaded from using automotive paint on future builds unless I am craving a really exotic color on a really big rocket.

After applying two coats of the spray paint to the front half of the rocket I see that orange is clearly the right color for the G-Force. I am now considering pin-striping some orange flames down the Lower half of the rocket.

Here is what our current fleet under construction looks like now. We have the G-force in black/orange. Big Bertha and Der Red Max in sand and fill primer. Nothing like the smell of paint fumes in the house while the rockets are atop the boiler to dry.

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stickershock23

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Trident,

The rocket is looking great... Any True automotive paint is not cheap. especially when you get into colors like the cobalt, pearls etc. a quart of even decent automotive 2 part sandable primer goes for $20. out here OUCH...

anyways I like the black and orange.. Can I set you up with some G-force decals in Orange to something to match? By the way I do custom vinyl decals.. and that rocket SCREAMS for some cool contrasting stripes or something like that.. I can also hook you up with flames for that. I even do Paint masks if you really want to paint them yourself.

Thanks for all the Build details. Thats a great first mid power rocket!
 
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1974_Trident

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Well, thank you for recommending your decals, Stickershock. while I haven't committed to such a decision I am considering using the factory supplied Aerotech decals so I can say I followed some of the directions when I built my rocket. As far as pin-striping the flames, I have some pin-striping experience from a youth spent around cars and motorcycles. My wife also worked in a body shop. She was the bookkeeper but was asked to do the more intricate pin-striping when the shop owner found out she was better at it than the guys who went to school for it were. I even have a pattern in mind, the flames on the sleeves of an old Harley Davidson t-shirt which I have, I just need to scan them into my computer and print them out. follow the flames with a roller punch pin pricker thingy and trace the pattern onto the rocket with talcum powder.

I will, however consider decals. Orange "G-Force" decals are sounding quite nice.
 

1974_Trident

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So the top half of the rocket is a nice vibrant shade of orange and the lower half is in primer again. I must say, bad technique with the automotive paint has cost me too much time. Certainly more than the money I thought I was saving by using paint I already have in the garage. I spent more time sanding off the bad paint job than I would have spent on the entire paint phase had I used spray paint from the beginning.

Lesson learned; never wet sand a cardboard tubed rocket. The tube ends absorb the water and get all soft and distorted. I decided to trim about 5/16" off the front tend of the rear half of the rocket. I found that the body tube fits tightly inside a piece of four inch schedule 40 PVC pipe. I was fortunate enough to have a length laying around that still had the factory cut end. With a bit of soap and some gentle persuading I slipped a two inch band of four inch pipe over the end of the rocket and used it as a guide to trim off the boogie dooed end of the tube. Looks like a brand new tube now.

I better get this rocket done really soon. Each day that goes by I get ideas for more complex flame designs. I already put the Aerotech stripes decal on and took it off after only an hour. I did not like it.
 

1974_Trident

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It's finally finished.

Just finished attaching the shock cord and parachute. For the first time ever I have seen my G-Force in its complete form.

I decided to use a flame pattern from the sleeve of one of my Harley Davidson T-Shirts. Well, kinda. The flames on the shirt fade yellow to orange from the center of each flame out. I am not that talented with making paint masks so I did the fade from orange to yellow front to rear. I am pleased with the results. The wrinkling which arose when I sprayed the clear coat over week old orange has nearly completely settled, I have to look hard to find it.

I can't wait to fly it this weekend, I just hope the weather permits.

A concern i have now is the finished weight of the rocket. The instructions and all marketing data for the G-Force all say the rocket weighs 907g. I put the finished rocket on a triple beam balance and it weighs in at a whopping 1479g without a motor. A loaded motor adds another 143.69g which places this rocket well above the 1500g threshold established by FAR 101.22. Aside from regulatory burdens I am also concerned about the air worthiness of this rocket on G impulse. All of the advertised literature promises flights of 800 ft. flights (1200 ft. with a G-80T). I am now wondering if I will make a spectacular lawn dart. I guess I should get some G-80Ts to play it safe.

Has anybody here ever built and weighed a complete G-Force? Did I really add an additional pound of paint and epoxy? I know I used Approximately 4 oz of epoxy for fillets which are not mentioned in the directions. On Aerotech's website there is a video showing assembly of a rocket which looks like it could be a G-Force and no filleting was done. I just can't see building a rocket without filleting. I have to now go into my garage and count empty paint cans which promises to be an exercise in futility, I sanded off most of the paint I applied. I have no Idea how much over spray is on the garage floor except it is a lot.

I am really afraid to fly this rocket now after all of the time I put into it.

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terryg

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At that weight rocksim gives the following results:

The G64W and G76G reloads give an altitude of ~ 600ft with an optimal delay of 4.5 sec

The G80T gives an altitude of ~ 775 ft with an optimal delay of 5.5 sec

Low and slow easy to recover flights. Launch in low winds for best results. It will really get the best flights when you get into the smaller high power loads.

H128W gives ~ 950 ft and the H165R gives a little over 1000 ft.
 

1974_Trident

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TerryG, Thank you very much. It is good news that my rocket will still achieve fun altitudes. I really don't want to fly this rocket too high. After all of the effort I put into the paint I would hate to scuff it on a communications or GPS satellite.

I am planing on my first launch this weekend. Actually this is going to be a family launch fest. My sons are anxiously waiting to fly their new Big Bertha and Der Red max while my Daughter's Alpha is in between coats of paint as I type this. Pink and purple of course.

I have a pile of reloads as well as A through C engines to bring along. Weather permitting, this should be a fun weekend.
 

UPscaler

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TerryG, Thank you very much. It is good news that my rocket will still achieve fun altitudes. I really don't want to fly this rocket too high. After all of the effort I put into the paint I would hate to scuff it on a communications or GPS satellite.

I am planing on my first launch this weekend. Actually this is going to be a family launch fest. My sons are anxiously waiting to fly their new Big Bertha and Der Red max while my Daughter's Alpha is in between coats of paint as I type this. Pink and purple of course.

I have a pile of reloads as well as A through C engines to bring along. Weather permitting, this should be a fun weekend.
GREAT paint job! Your rocket looks fantastic. Using a retainer was a good plan too! Now when you are ready for bigger motors, you can fly them in your G- force. I highly recommend the 29/240 case. It has a great selection of H motors!
 

blackjack2564

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Mine weighs 3.6lbs.[pretty darn close to yours]

Fly it on G-64 4sec delay.....perfect flight to around 500ft consistently.

Also fly it on H-165 to 1100ft
H-97 to 1280

I put little cheapie altimeter in payload to get those heights.

You will be fine.
 

SuperSlim

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I even see possibilities with a G53-5 which seems like it would give a nice slow liftoff for my viewing pleasure. I may even get a few F loads.
I had a G-Force for a brief time and I have seen several launched. I would steer clear of the G53 or anything smaller. I certainly would not tempt fate by shooting an F either, unless of course you are going to video the crash and post it on You Tube. If you look at Aerotech's recommendations, they don't recommend Black Jack or F motors.

The G-Force is a cool rocket but it turns land shark in a hurry unless you put some oomph behind it.
 
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