How to: Mid-High Power Fillets

Here is how I make my beautiful, smooth as a baby's butt, strong as a mule fillets, with no sanding! OK, some sanding could make them better, but you get the drift. This is just my way, it is not the cheapest, easiest, or strongest way, but it works for me and I have not yet cracked a fin fillet using this method. As they say, there is more than one way to bake a cake.

What you need:
Epoxy (any type will do, I still use El Cheapo 30 minute epoxy.)
Milled Fiberglass (for extra strength and a higher viscosity(linky))
Protection (Gloves, particle mask because of the milled fiberglass, newspaper, etc.)
Smoothing tool* (a used Estes motor, a washer, a plastic spoon- something to smooth out the fillet with)
Masking Tape
Sharpie
Something to mix the epoxy (weapons of choice: Popsicle sticks and a paper plate)
Sandpaper or a Dremel (optional)
Soapy Water (optional)

The Materials
Note: Incredibly messy table not necessary.

1. Rough up the junction between the fin and body tube exterior, using 60-80 grit sandpaper or a Dremel. This helps the epoxy bond to the two parts and creates a stronger fillet. After doing so, rinse and dry the parts in water with or without soap to get rid of any dust or oils from your hands in the fillet area. This also helps improve the bond between the fillet and the rocket.

2. Get all of your materials ready: Lay down some newspaper to protect your table, put on some gloves to protect your hands, a particle mask for your lungs, etc. Always wear protective gear! Epoxy and milled fiberglass are both very nasty materials. Tip: having napkins handy to wipe up any Oopsies will certainly be a plus.

3. Mark the tube using your smoothing tool and a Sharpie. Liberally coat the end of the smoothing tool with Sharpie ink, and then run it down the tube as if smoothing out a fillet. This shows you where to lay down the masking tape (next step).

Masking tape "dams" for the epoxy.

4. Put down masking tape along the lines you just made and on the bottoms of the fins too (left). This catches any stray drips of epoxy, leaving you with a drip-less fillet. Depending on when you take the masking tape off will determine how much sanding you have to do later. If you take it off too early, it might drip, too late and it will leave little ridges on the edge of the fillet that you will have to sand down.

5. Mix up a batch of epoxy- I usually try to mix a little less than what I think I need, because I would rather mix new epoxy than waste some. Add some milled fiberglass after the epoxy is mixed a little bit. You don't have to worry about too much or too little, but the manufacturer recommends a ratio of about one part fiberglass to eight parts epoxy, which sounds like a little less than what I use, but you could probably even do a ratio of 1:2 if you wanted to, but it would be very difficult to work with. 1:6 or 7 seems to be what I use, but it really doesn't matter.

6. Once you put the fiberglass on top of the epoxy, mix it all up until it is evenly distributed and it all looks uniform. Now to the actual filleting!

7. Slather some epoxy on the area to be filleted, and smooth it out once with your tool. Do not smooth it down multiple times, because that will create little bumps/ridges in the fillet where you started smoothing anew. Take the tape off as soon as possible, and let the epoxy set. Then you can move on to the next set of fillets!

Voila, the final result! These fillets seriously feel like glass.

* You can use just about anything to make the fillet smooth. Small cylinders such as used Estes 18mm motors can be used, and large washers for larger fillets. You want your fillet to be big enough to strengthen the fin, but small enough so it doesn't look ridiculous, add unnecessary drag, or both. In order to find the right one for the job, just place a candidate on the joint between the fin and the body tube, and judge if the fillet width is too big, too small, or just right (see below).

How the smoothing tool works. The area between
the tool and the fin/body junction is where the fillet will be.

Updates

All right, it's been a while since I posted here last, so I think I'd like to get into making more posts. Since the last post, I've gotten Jr. Level 1 certified with the NAR. I did this back in March, with my Drago on a Cesaroni H163(right). It flew to about 2,800 feet and went about 400mph, the fastest and highest I've ever flown. Above is a picture from the rocket's highest altitude, with the rows of cars visible. The date in the lower right of the image is incorrect, though. It was a perfect flight, despite landing on a metal roof and subsequently falling onto a gravel road. It's one tough rocket! Also, as a sort of celebratory launch, I flew my first sparky motor, which you need to be certified to fly since it spits out large amounts of sparks that could start fires. The motor was a G106, and it flew to about 1,700 feet(left). The rocket suffered a little damage, though, but it will fly again.

Another one of my projects over the school year was TARC, Team America Rocketry Challenge, which is a national rocketry competition where you have to fly a rocket to a certain altitude with a one or two eggs inside of it, and bring it back down in a certain amount of time. The years change each year, and the past year's rules were: two eggs, altitude of 800 feet, and a flight duration of 43-47 seconds. The closest to the altitude and duration gets the highest score. My friends and I had a great time, although due to tricky winds, we didn't make it to the finals. We are looking forward to doing it again next year! Below is an image of our rocket lifting off.

During April, I attended Red Glare XII, which was fun as always. I flew two new rockets, the Wild Child, an all fiberglass rocket designed for high altitudes on small motors, and the Cowabunga, a four inch diameter, three pound monster designed to have fun, "slow-n-low" flights. I had six flights over the weekend, an F36, an F59, a G68, an H163, an H87, and an H237. Unfortunately, my Drago broke two of its fins due to a badly wrapped parachute. It will fly again. It was cloudy when most of my rockets flew, so there aren't any good pictures, unfortunately.

One of my current projects is an electronic deployment project, which I am basing off of this video. As far as I know, I will be the first one to use this form of deployment on a High power rocket. The reason that I'm doing this project is because, as a minor, I can't purchase black powder or other explosive materials that are usually used for dual deployment. Dual deployment is basically when you have two different parachutes on a rocket, a small one and a large one, and you deploy the smaller one at the highest altitude and the larger one at a lower altitude. This doesn't let the rocket drift as far in the wind. The full thread on The Rocketry Forum is here. Note that there was quite a learning curve, and I began the project with barely any knowledge about it at all. Later on in the thread I began to learn more and become more literate with the parts and electronics.

Otherwise, I haven't been able to do much rocket work this summer. My other two current projects are a short and stubby 2.6" rocket called the Lil' Goblin (it's so small the parachute has to be packed in the nose cone) and a 2" diameter five and a half foot tall fiberglass rocket that will weigh at least 4 lbs when fully built. I may not even be able to finish it until next summer, since it has many different parts and I want to take my time while building it. And, homework and my rocketry club slow me down a ton during the school year.

I'll leave you with this picture, which I think is pretty neat. It is my Lil' Nuke rocket on an E18, one of my favorite rocket/motor combinations. Thanks for viewing!

Red Glare X

Red Glare X was awesome, and one of my favorite rocket events to date. Here is a quick flight report of the major flights.

I arrived at the launch site mid-day on Friday, and only launched a small Estes cluster rocket before the rain came and I headed out. The next day, the weather was more promising. I launched my new LOC/Precision Black Brant X on a F35 for its first flight (right). It was slow and low, but went very well. I also flew my Wildman Rocketry Darkstar Lite on a G76 Mojave Green (left). I attached my micro keychain camera to the rocket, as I was expecting awesome footage from a 1,400 foot flight. The boost was swift atop a green flame, and was perfectly straight. Unfortunately, due to a faulty homemade retention system, the energy of the ejection charge went into breaking the weak epoxy joint on the motor retention instead of fully deploying the parachute. The rocket flat-spun down and literally cracked one of the fillets right off. It has just been easily repaired, and the rocket will fly again soon, but with a new retention system. But, apparently, the impact caused the micro keychain camera to not record a single second of video from the flight! Although that was a major bummer, that didn't stop me from flying my Wildman Drago (below) on a Cesaroni Pro29 3-grain G54 moon-burner. This was the biggest motor I could fly before I get certified, but it was an easy prep with a Aero Pack retainer and the low assembly Cesaroni motor, the rocket was ready to go in a short time. The motor lit instantly, and the rocket streaked into the sky atop an awesome red flame. The motor just kept going and going! The rocket went to about 2,500 feet, and it would have gone higher if the rocket didn't have a strange tilt immediately after it left the launch pad. There was little wind, and the rocket had a safe, close recovery. That concluded Saturday, and the weather for Sunday was promising another great day of rockets.

On Sunday, the first to go up was the Black Brant X again on an Aerotech F62 with a reload adapter system in a 29/180 case. The boost was quick, but after about a second from motor burnout, my personally drilled delay burned through too early and popped out the parachute. Oops! I think I'll be more careful drilling my delays. The only damage was a snapped shroud line on the parachute because of the high speed ejection, but since the rocket was only a couple hundred feet in the air, the rocket was unharmed. After that, I flew my Lil' Nuke on an Aerotech F24-7 (left) for a nice, quick flight to 800 feet. The ejection of the parachute was pretty late, so I think a 4 second delay would be better. For the last flight of the launch, my stretched and very heavy (the nose cone is filled with a ton of steel shot and epoxy) Madcow Rocketry PAC-3 flew on an Aerotech G64 (below).  The motor came up to pressure instantly and the rocket took off quickly with a sharp left turn of about 15 degrees off of vertical, but straightened out in a split second. I think that next time, I should use a longer launch rail for such a heavy rocket. The rocket headed pretty far downrange and suffered from a late deployment and a failure of the parachute to exit the body tube to recover the rocket at a slow rate. Fortunately, there was little damage when it hit the ground, only a partially cracked fin fillet and a bent body tube. It is currently waiting a fresh new paint job and should be clean and spiffy very soon.

Christmas Loot, High Speed Camera and Just Plain Ol' News

I completely racked in all of the rocket stuff I could've wanted. I got multiple rocket kits, some of which are a LOC/Precision 2" Black Brant X (one of my favorite rocket designs), a Madcow Rocketry PAC-3 and a Wildman Drago, and I couldn't have had a more fun time building these rockets, although I've still got a bit to work on for the first two, but they should be finished soon enough. I got numerous motors and motor cases and hardware, but probably the coolest present I got was a Casio FH-100 high speed camera, which provides me with tons of entertainment, related to rockets or not. It takes great pictures and is like a miniature DSLR camera, for a fraction of the price. I really love it!

As I've said, I've done a ton of work on rockets, and I did get a chance to fly two of the five large rockets I got during the holiday season. These two rockets were a LOC/Precision Lil' Nuke and the Drago. Both were flown at the February launch at Culpeper, and performed great. The new rockets were only in primer, as there were not many opportunities for painting in this season. I arrived to the launch somewhat skeptical, as the weather was to be perfect if it wasn't for the high winds that were supposed to come. The wind wasn't horrible and it was blowing in a favorable direction, so I decided to fly the Lil' Nuke on a E18-4, which had a nice, swift ride to about 800 feet, with a nice recovery in the soft mud. Unfortunately, I didn't get a liftoff video or picture. After that, I flew my Apogee Components Nemsar on an E9-8. It went WAY higher than expected, over 1,200 feet by the looks of it. The rocket separated at apogee, and the two pieces came down not too far away, but i just couldn't find them after over an hour of searching. Apparently, someone found the two rocket parts while I was looking for it. They brought it to me after I was looking for quite some time. Well, the shock cord seemed to come off from the heat of the ejection charge melting the glue that attached it to the motor mount. But thankfully, all is repairable and it will fly again. After that, and seeing everyone else's rockets recover relatively close, I built up enough courage to fly the Drago on a reloadable G79-8 motor in a 29/180 case using a Reload Adapter System. The boost was wonderful, with a loud roar and a sweet roar. It went lower than expected, probably lower than 1,400 feet, but I got a ton of great liftoff pictures with my camera, as one is shown below. The recovery was great, if a little late, with a 21" CATO 'Chutes hemispherical parachute, which looked very cool and realistic coming down. It was a great flight, and performed perfectly. To top it all off, I flew my good ol' trusty Rock-It on an E9-8 for a great flight. Overall, it was a great launch and I got a ton of nice videos. I'd like to share them, but I have to upload them to YouTube first. So for now, I'll give you a few pictures from the launch.

Lil' Nuke recovery.

The Drago on the pad.

Drago liftoff.

Rock-It recovery.

Edit: This was made a long time ago, and I have been slacking off on this blog. Expect more posts and flight reports as the summer progresses.
Happy Flying!

Red Glare IX and Recent Rocket Activities

Star Spangled Eagle ready to launch.

Darkstar Lite on the launch pad.

I haven't posted in a while, so any of my readers may be surprised with this really long post. I plan to post much more often, so check every month or so. First, I'd like to say that one of my most anticipated projects for Red Glare IX was a Wildman Darkstar Lite fiberglass rocket , which I constructed last minute for it's first flight at Red Glare. I will concentrate on the larger flights, but I'll go in the order they were flown. First, I "flew" an Estes D-Region Tomahawk on a E18, but due to a tight rod, the rocket didn't clear the launch pad. The weather was great on Saturday, so we decided to launch the Darkstar Lite on a Aerotech G71 redline, to an expected altitude of 2,000 feet. The boost was fast and straight with a huge red flame nearly a foot long. Unfortunately, the parachute deployed early so the maximum altitude was about 1,400 feet. A fairly successful flight, but it's begging for more. The next flight should be on another G motor of some sort. My last flight on Saturday was my Estes CC Express on 2 D12s. That was a successful flight to maybe 1,500 feet. After a good night's sleep, I was ready to roll the next morning with a personal altitude record attempt. The rocket was a LOC/Precision Weasel dubbed the Star Spangled Eagle , and it would fly on a Aerotech G64 white lightning, which would hit an altitude of up to 3,500 feet and a maximum speed of up to 500 mph, about 0.65 times the speed of sound, velocities and accelerations that I have never before experienced with a model rocket. I was obviously nervous, especially with a few family members observing the flight. The rocket took off very fast with a nearly 18 inch flame and a loud roar, until about 1,200 feet where the payload (blue) section and nosecone came off, but the booster section continued upwards for about three seconds until the parachute was forced out. It turns out that the shock cord untied instantly from the payload section, so the two sections weren't together the whole flight. So, what happened? Well, we know a few things from the results. There was certainly no motor failure of any sort, the parachute did not deploy the same moment the payload fell off, and the flight was nominal before the separation. So, I deduced that the two sections separated by either one of two theories, but possibly both. The first theory is that the pressure change in altitude caused high pressure inside the rocket pushing the upper section away from the lower section, and that is fixed by drilling two small holes for equalizing any major pressure differences, which I did. The other explanation is that the rocket started "corkscrewing", which is caused by fin misalignment and increases the angle of attack and drag on the rocket. Although I didn't see it doing this, it could have occurred and put extra force on the rocket in a different direction. I flew it later on a F35 white with vent holes and a onboard camera and it had a slight corkscrew, which might have just been the camera, but that makes me think that the second possibility could have happened. Continuing on with the launch, I flew my Semroc Astronautics 50% scale Arcas research rocket on an Aerotech F35, with a beautiful, fast boost to about 1,500 feet. My last flight at Red Glare IX was my Big Daddy on a E9 for a low, cool flight.

Arcas on a F35. Photo by Nick DeBrita

The only launches I went to after Red Glare were a launch at Culpeper, that was probably the worst launch in my life, due to very windy and cold weather along with me having a very sore throat, and a launch at NOVAAR which I flew my Barracuda on a F39 blue and the Star Spangled Eagle test flight that I mentioned earlier. I haven't done much rocket construction lately, but I am planning on getting a Casio high speed camera by February, so I'm planning a few flights that would be cool to see in slow-motion. I hope to get a YouTube account in the near future to show my videos of rocketry.

Please comment and have a happy and safe holiday season!

Epic Michael's Win, work on Terrier Orion

Yesterday when I was looking around Michael's, I sadly found out that they were getting rid of their rocket stuff, and all they had left were a few kits, one of them being the Super Neon, marked down to $6, an excellent deal! Looks like a cool kit, and I already finished the motor mount. I just put the first few fins on the Terrier Orion, and already glued in the motor mount and all that. I plan on flying it before the end of this month, probably without the final paint job, which is in the actual rocket shown below. I'm looking forward to flying it!
                        

Thinking Out Loud: Quest Terrier-Orion plus Estes Tomahawk Cruise Missile Frame grab

This is a kit that I got a long time ago (when dinosaurs ruled the Earth) and, upon opening it today, looks like a very cool kit, and one of my first scale kits. (I have only three scale rockets out of forty-odd, including this one!) I'm looking forward to building it! This would be a good rocket to use all of my Estes C6-3s up on, I have a ton of them from Blastoff Flight Packs!

Photos by Todd Mullin and Brian Ray respectively, left to right.

This is a cropped frame grab of an Estes Tomahawk Cruise Missile on an A10 in a field by my house which was taken by a micro keychain video camera attached to one of the pad legs. It's an excellent camera, is very compact and cheap, and takes 640x480 video. And, with a 4-gig microSD card, it can take over 50 minutes of video nonstop.