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3stoogesrocketry

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After posting a couple photos in Dan's thread , I received a few private messages from others asking how I built the rocket so far . I decided I will do a quick detailed write up on the construction and flight in the spring . The rocket is a rebuild of a 1/4 scale ARIES I built in the late 90's inspired by Ray Halm and Andy Schektner's one half scale flown at LDRS in Argonia in 1996(?) On 4 M1939's. My origanal rocket was all PML 11.5 components and weighed 108 pounds loaded with a single M2500. After many , many hours of trying decide how to get 10 pounds of parachutes into a 5 pound space , I shelved the rocket for a smaller cheaper design. The rocket was later destroyed when it fell over in the garage . 35 pounds of lead in the top 10 inches of the cone sheared the nose cone in half and broke the main body tube.

ARIES part 2 is a light weight design that will be a single deploy pop it at the top style . I spent about 2 weeks doing 4 different build versions in open rocket before I found the best design for what I was looking to do .

The construction of the rocket is very basic and my 7 year old daughter is doing alot of the construction (supervised) and is her first "big" rocket. Last year she started out with Estes and likes the bigger stuff .

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3stoogesrocketry

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I settled on quarter scale for two reasons:

1. The size of the motors I wanted to use (38mm) to get the altitude I was looking to get (1500 to 3000 feet)
2. I'm working on a single parent budget and have a storage unit of old parts I can use.

The basic construction of the rocket consists of two parts , the fin can / lower airframe , and the nose cone / upper airframe / AV bay.

I had a pile of PML 11.5 to 7.5 centering rings and bulk plates in body tube size and coupler tube size. I decided to use the coupler tube inside diameter as my rockets outside diameter.

I used one of the centering rings as a guide at my shop and used my router to make a mess and buzzed out a 4 by 8 sheet of 25psi 2 inch thick Blue Board.
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3stoogesrocketry

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The fin can / lower airframe started life as a 48 inch length of 8 inch Quik-Tube from my local Lowe's. I decided on using a 7.5 inch PML coupler before hand so I brought that along with me to get the right tube. Once I had the tube , I cut it down to 30 inches. We glued one half inch thick ring to one end of the 30 inch long tube. This is the TOP of the fin can lower airframe where it will be deploying , so I wanted a little rigidity . Then using a 2 part epoxy similar to West Systems , we glued 8 foam doughnuts onto the yellow tube and a 1/4 inch thick centering ring I split in half from one of the 1/2 inch thick rings . With the wet assembly upside down I put 80 pounds of weight evenly around the 1/4 inch ring to compress the sandwich together to cure. After it dried over night , my daughter used a 24 inch body block with 50 grit to quickly level the foam using the centering rings as sanding guides. She then used a light weight joint compound called Plus 3 to fill in all the low spots.
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3stoogesrocketry

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After she cake frosted my rocket , we used a 24 inch drywall straight edge to pull a nice smooth finish. After a quick touch up with 120 grit we had a nice smooth base to work the glass onto . I then sent her off to play while I put a single layer of fiberglass onto to tube using 2 part epoxy leaving a nice finish .
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The fins will be made out of 1 inch blue board cut and sanded to shape with the transition being glued in 4 separate quadrants after the fins are secured.
 

3stoogesrocketry

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The nose cone / upper tube / AV bay are all one section . I used a 48 inch section 38mm Blue Tube 2.0 Ive had for several years as a core tube / adjustable weight tube as the inside diameter shrank well below usable use as a motor mount. Using a PML coupler 1/2 inch thick bulk plate , I found the center and blasted a 1.5 hole in it with a hole saw and gave it a final adjustment with a 60 grit flapper wheel . I then used 3 speed squares to make sure the tube was perfectly perpendicular to the bulk plate .

When I was cutting doughnuts out of the blue board , I cut 13 with a 1.5 center hole in them to act as the upper airframe and AV bay / lower noes transition. 6 of the foam rings got glued onto the 1/2 inch ring , along with the other 1/4 inch thick split PML Ring on top and compressed. After that dried we glued the 7 other onto the 1/4 inch ring and compressed them with a 3/8ths 9.5 inch OD ring to the 38mm tube and compressed to dry. We then glued four 10 inch diameter to 38mm doughnuts and 5 of 7 inch doughnuts onto the tower , compressed with a 3 inch to 38mm 1/4 inch ring.
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3stoogesrocketry

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The rings on my nose cone act as sanding guides in key places to get the correct shape . To shape the cone roughly I used a wood hand saw to get a 8 sided looking shape. Then I made two wooden pillow blocks / plates to spin the rocket . I glued the 11 inch to 38mm template onto the end of the tube and attached a handle. We then spun the rocket and used 50 grit sandpaper on my 24 inch body block to get a nice consistent shape . She used the filler to make it smooth , I then glasses it all.
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3stoogesrocketry

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As far as the rocket couples together , the PML 7.5 inch coupler bolts onto the bottom of the nose cone . There is a half inch plate glued into the 7.5 inch coupler. Before I glued the nose all together , I drilled and installed 4 3/8ths tee nuts 5 inches on center into the bottom of the 1/2 inch centering ring on the bottom of the cone
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The thought with this is duel use.

1. If and when the coupler gets damaged I can simply make a new one and bolt it on .
2. To add noes weight I will have a 3/8ths threaded rod running up the center of the tube into the tip . I will use a threaded eye nut to secure the weight as well as a attachment point for the recovery .
 

3stoogesrocketry

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If you look at the black and white photo , the rocket will separate right above the PMR letters.
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And the AV bay will be about where the Black horizontal line is under USN. I plan on inserting 2 38mm tubes horizontal into the side of the main body tube and these will act as my electronics bay . Then I just need to slide a vented plug in to keep everything secured. Current plans are single deploy , but capable of using my AARD for DD later down the road. The black tip will be a hunk of mahogany turned on my lathe.
 

kuririn

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Four motor cluster like the original Fat Albert?
 

3stoogesrocketry

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Current sims put the rocket at 23 pounds full up minus motors. The 7.5 inch core tube will house a removable cluster mount. The first flight will consist of 4 x 38mm Loki I405 motors. On the pad it will weigh roughly 32 pounds with the 6 pounds of needed ballast. Simms say 1850 feet at 260 mph.


Also I have been asked about rail buttons. On the front of the fin can I installed a 2 inch cubed block of white pine treated with epoxy screwed to the front 1/2 inch thick ring before we glasses the tube. The rear button will be secured in similar fashion. 1515 buttons.
 
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ThirstyBarbarian

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As far as the rocket couples together , the PML 7.5 inch coupler bolts onto the bottom of the nose cone . There is a half inch plate glued into the 7.5 inch coupler. Before I glued the nose all together , I drilled and installed 4 3/8ths tee nuts 5 inches on center into the bottom of the 1/2 inch centering ring on the bottom of the cone View attachment 451687View attachment 451688


The thought with this is duel use.

1. If and when the coupler gets damaged I can simply make a new one and bolt it on .
2. To add noes weight I will have a 3/8ths threaded rod running up the center of the tube into the tip . I will use a threaded eye nut to secure the weight as well as a attachment point for the recovery .
I like this setup a lot. It‘s great you have an option to easily replace the coupler if necessary. And the adjustable nose weight system is a good idea too — I’m looking forward to seeing exactly how you do that.
 

ThirstyBarbarian

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Can you tell me what weight of glass fabric you used and how many layers?

When I made mine, I just hand laid some 3oz glass in a single layer to keep it from getting dings and to make a paintable surface. I was trying to keep it extremely light, but it still added weight. For most of the rocket, it was more than enough, but the tips of the fins have still been damaged a bit on landing, and mine is only a 4-pound rocket. You mentioned using blue board for the fins. What are you doing to beef those up? I’m thinking as I build bigger foam rockets, I’ll need much tougher fins than what I have on my first one.
 

3stoogesrocketry

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Can you tell me what weight of glass fabric you used and how many layers?

When I made mine, I just hand laid some 3oz glass in a single layer to keep it from getting dings and to make a paintable surface. I was trying to keep it extremely light, but it still added weight. For most of the rocket, it was more than enough, but the tips of the fins have still been damaged a bit on landing, and mine is only a 4-pound rocket. You mentioned using blue board for the fins. What are you doing to beef those up? I’m thinking as I build bigger foam rockets, I’ll need much tougher fins than what I have on my first one.
As far as the fiber glassing goes , the glass I used shown above is just the standard Bondo automotive fiberglass any auto store sells . The glass is 25 x 49 and I'm guessing around 4 or 5oz , and a very loose weave. I like using it because it conforms very nicely to complex shapes and wets out very easy. I used around 3 packs total and 10 pumps of West Style epoxy 5 to 1 with a fast hardener.

I have a couple rolls of different glass that I'm going to try on a test fin , but most likely it will be 3 layers of a heavy 8 to 10 oz not sure glass.
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The fins will be glued on with three quarter inch radius West and chopped glass. Then I will use 4 layers tip to tip of the auto motive style .
 

3stoogesrocketry

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Here is one of 4 full scale Iris fins for a foam project that has taken a 4 year break , but is coming back this year.
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That is a 18 inch ruler on it for scale . It is currently sitting on two 1 inch thick slate slabs .
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There is zero deflection with 75 pounds on the fin

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3stoogesrocketry

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I have cut out a few mock up fins to do some profile testing and glass testing on . Once im satisfied I will show my process.
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