LOC PRECISION was acquired by Barry Lynch in 2000 from Ron Schultz of Ohio. Over the next 16 years Barry took LOC to the next level by investing in LOC to do more….fly higher, more affordably and added touches of modern day quality. What Barry has given to LOC, he set industry standards for others to follow. Expanding the company to do more for education, youth and investing in the next generation of HPR flyers. In November 2016 LOC changed hands again, and it was more than a business transaction. It turned into a friendship! For Dave Barber and Jason Turicik of Plymouth Wisconsin it is a dream come true to have the blessing to work with their passions for design every day. Dave and Jason bring experience as previous owners of Yank Enterprises. As young entrepreneurs they had a catalog of over 20 rocket kits before the age of 21.
They bring fresh insight and new ideas. They promise to deliver exciting new selections, but also bring back "Retro" versions of the much loved classics from the good ol' days. They love working close with customers, and are open to phone calls, emails and Facebook feedback. They are happy to discuss custom orders and special requests. Along with traditions they will work to keep the relationships with educators to pass this hobby along to the next generation starting out through school. Very importantly, they value the ability to create and offer kits that are affordable for a Dad to take kids out to a launch. These guys are dedicated to maintain the high quality and service that LOC provided to customers over the last 31 years.
435A Factory Street
Plymouth, WI 53073
Phone: (920) 892-0557
Since its founding in 1982, AeroTech has grown to become the largest supplier of "D" through "G" power composite model rocket motors, mid-power rocket kits and related products and "H" through "N" high power rocket motors in the world. If you have flown any mid-power or high-power rockets. You have no doubt used an Aerotech product.
AeroTech has been producing rocket motors for the motion picture special effects industry since the early 1980`s. AeroTech rocket motors have been featured in numerous motion pictures since then, and you can look for them in "Iron Eagle", Delta Force 2", "Tank Girl", "Star Trek: Generations," "Tomorrow Never Dies," and "October Sky". AeroTech also supplies rocket motors to educational institutions and rocket parts to other hobby rocket kit manufacturers. AeroTech kits and motors have been featured in a National Geographic article and PBS television show on thunderstorm research, a Travel Channel special on Ray Halm`s "Aries" project, a "Junkyard Wars" episode and a Discovery Channel "Mythbusters" program on the legend of Wan Hu.
The core strength of AeroTech`s product line is its composite propellant rocket motor technology. Compared to conventional black powder propellant, composite propellant can produce up to three times the power for the same propellant weight. In addition, composite propellant technology permits the creation of rocket motors with performance characteristics and sound and visual effects not possible with black powder propellant technology.
Charlie will be onsite to talk about Aerotech's newest products, answer questions and remind us just how cool Aerotech is!
AeroTech Consumer Aerospace Division
RCS Rocket Motor Components, Inc.
2113 W. 850 N. Street
Cedar City, UT 84721
Located in Salt Lake City, UT serving members of the Utah Rocket Club and featuring Aerotech single use, disposable and reloadable motors. Flight supplies featuring AeroPac retainers, TopFlight Recovery, & Missile Works altimeters. You may place an order online on his website. Items may or may not be available as this is not a store front but support for local rocket flyers. Contact Das Rocket Hobbies to pre-order/pay for delivery at Utah Rocket Club meetings, special club events, or pre-launch. If an item is unavailable, contact DRH. DRH will try to work with you to obtain needed motor reloads or flight suppiles for your high power rocketry club flying needs. Das Rocket does not ship rocket motors!
Have a HellFire XXII motor need?
Message me what you need in AT 38mm, 29 mm, & 24mm. (Charlie says 54 mm and up are off the shelf right now).
Get a DAS Rocket order in now for 54mm and higher to be made now by AT and delivered at HellFire.
Das Rocket Hobbies
1352 Farm Meadow Lane
Salt Lake City, UT 84117
Sport rocket motors approved for sale in the United States are stamped with a three-part code that gives the modeler some basic information about the motor's power and behavior. For example, a "C6-3" designation indicates that the total impulse of the motor ("C"), This number specifies the average thrust ("6"), and finally, the last number indicates the time delay between burnout and recovery ejection ("3").
Total impulse is a measure of the overall total energy contained in a motor, and is measured in Newton-seconds. The letter "C" in our example motor above tells us that there is anywhere from 5.01 to 10.0 N-sec of total impulse available in this motor.
In a typical hobby store you will be able to find engines in power classes from 1/2A to D. However, E, F, and some G motors are also classified as model rocket motors, and modelers certified for high power rocketry by the NAR can purchase motors ranging from G to K.
Since each letter represents twice the power range of the previous letter, total available power increases rapidly the further you progress through the alphabet.
Average thrust is a measure of how slowly or quickly the motor delivers its total energy, and is measured in Newtons. The "6" in our example motor tells us that the energy is delivered at a moderate rate (over about 1.7 seconds). A C4 would deliver weaker thrust over a longer time (about 2.5 seconds), while a C10 would deliver a strong thrust for a shorter time (about a second).
As a rule of thumb, the thrust duration of a motor can be approximated by dividing its total impulse by its average thrust.
Keep in mind that you cannot assume that the actual total impulse of a motor lies at the top end of its letter's power range -- an engine marked "C" might be engineered to deliver only 5.5 Newton-seconds, not 10.
The rocket is traveling very fast at the instant of motor burnout. The time delay allows the rocket to coast to its maximum altitude and slow down before the recovery system (such as a parachute) is activated by the ejection charge.
The time delay is indicated on our sample motor is 3 seconds. Other typical delay choices for C engines are 5 and 7. Longer delays are best for lighter rockets, which will coast upwards for a long time. Heavier rockets usually do better with shorter delays -- otherwise the rocket might fall back down to the ground during the delay time.
Motors marked with a time delay of 0 (e.g., "C6-0") are booster engines. They are not designed to activate recovery systems. They are intended for use as lower-stage engines in multi-stage rockets. They are designed to ignite the next stage engine immediately once their own thrust is finished. Often their labels are printed in a different color to help prevent you from using them in a typical rocket. In a multi-stage rocket, you would usually select a very long delay for your topmost engine.
First, please read the fine print... There are many different solutions to the rocket design challenge. Rules of Thumb simply provide a solid starting point that many have found useful in the past, and that will, in many cases, provide a suitable solution for your design problem today. Rules of Thumb are guidelines. They're not laws. They are nominal solutions that usually, in many cases, most of the time, get the designer in the right ballpark. Once a rocket designer's judgement has been formed by lots of experience, some Rules of Thumb can be stretched, bent, stood on their head, or ignored completely.
Using Rules of Thumb certainly does not take the place of stability tests, or attention to safety. Proof of stability and a constant focus on safety are the most fundamental and unchangeable Rules of Thumb I know. If you know Rules of Thumb that are not mentioned here, e-mail them to Tom Savoie and they could appear in a future update with your name as the contributor. Comments are always welcome.
Motor Mount Size
Build your rocket for the largest motor you might want to fly in it. You can always adapt down, you can never adapt never up.
Whatever your choice, use a primer, finish and clear coats that are compatible. Many times this means sticking to the same brands-e.g., Krylon primer, Krylon finish coat, and Krylon clear coat.
Diameter And Length Of The Rocket
The ratio of rocket length to diameter, sometimes referred to the aspect ratio, should be from 10 - 20:1. For example, a six inch diameter rocket would mean a length of 60 -120 inches.
Reinforcing the Airframe
The larger the rocket, the more important reinforcement becomes. Two layers of a lighter fiberglass fabric work better than a single heavy layer. Two layers of 4oz fiberglass works well for 3-4 inch rockets, 2-3 layers of 6oz for 5-7.5 inch rockets. A final wrap of 2 oz glass provides a good sanding veil. Glass a rocket measuring 2.56" or greater that will reach equal or greater than 0.85 Mach.
A fin that is 2 diameters of the airframe in root length and span and a chord length of about 1 diameter will be effective.
Fin Shape or Planform
The shape you see more than any other is called the clipped delta, and is known for its effectiveness. The clipped delta resembles a parallelogram, with the fin swept somewhat to the rear. The root and chord lines are near parallel, and the leading and trailing edges are near parallel. There are many, many shapes that will get the job done. Some look cooler to me than others. One of the most efficient fin designs looks like a simple rectangle attached to the tube.
Shaping the Fin
The leading edge of the fin should be rounded, the trailing edge shaped like a V. The chord edge should remain square.
Number of Fins
Three fins will almost always do the job. Four fins work too, but only marginally better as far as improving CP. Some have said that four fins reduce wind-induced spin.
Black Powder Ejection
Use enough BP to yield a 15 psi pressure within the airframe. See article on Ejection Charges for a detailed discussion.
Sizing The Parachute
You want your rocket to descend at about 15 feet per second under nominal conditions. Slow it up over playa and concrete. Use 3.5 square feet of chute per pound of recovered rocket weight. Determine chute size by doubling the square root of the weight of the rocket. For example, a 16 pound rocket would use a 2X4=8' chute. A 49 # rocket would use a 2X7=14' chute.
Streamers should be 10 times as long as they are wide.
Drogue recovery descent should be about 50 ft/sec.
A full-hemispherical canopy has very little performance gain over the more efficient and less bulky quarter-spherical--the top-half of a full-hemispherical chute.
Recovery Harness Strength
Tensile rating for recovery materials should be at least 50 times the static weight of the rocket.
Sizing Tubular Nylon
9/16" serves well in rockets up to 15 pounds. Go with 3/4 up to 30 pounds. 1" up to 50 pounds.
Length of model rocket shock cord
Make shock cords for model rockets a minimum of 2 to 3 times the overall length of the rocket. Middle or high power rockets should use tubular nylon at least 5 times the rocket length.
Use enough wadding to fill 2 x the diameter of your BT. Any more is probably overkill. Any less may allow hot particles through to hit your chute. Do not pack it tight.
Knots, Loops and Sharp Bends in Shock Cord or Bridle
Knots, sharp bends, including sewn loops, in the tubular nylon or flat webbing will weaken its load capacity by 50%.
How Tight is Tight?
Many people use masking tape to finesse the fit between an airframe and a coupler that must separate at deployment. A common question is: how tight do I want it to be? Use enough masking tape so that you can pick the rocket by the nose cone without the rocket coming apart. If you vigorously shake the rocket up and down, and don't see any movement off the coupler, you've probably got too much tape on, Jack.
Use 25% less Black Powder if your deployment system is piston driven.
Running a damp cloth through your airframe after flying will clean out powder residue and keep your piston moving freely.
Use shear pins on any rocket where you need a little extra piece of mind to know everything will stay in place until the proper time. Use 1/16" styrene rod or #2 nylon screws on almost any high performance rocket. For example two styrene shear pins each on a 2.6" phenolic airframe, 4 nylon screws on a 6" bird. See the article on Shear Pins in the CONSTRUCTION area for more detail.
Shortening Delay Elements
Note: Adjusting the delay as described below is considered a modification to the motor and is therefore against the rules in a TRA/NAR sanctioned launch. Delay grain burns at the rate of 1/32" per second. Shorten delay time by drilling a 1/16" bit to drill a hole into the ejection charge end of the delay. Drill to a depth of 1/32" for every second you want to shorten the delay. A piece of tape wrapped around the drill bit at the proper depth will help ensure an accurate depth. Don't drill more than 25% into the length of the delay.
Margin of Stability
The CG should be forward of the Center of Pressure by 1-2 calibers. A caliber is simply the diameter of the bird. One caliber of stability is also known as a margin of stability. In other words, in a four inch rocket, the CG must be ahead (closer to the nosecone) of the CP by 4 - 8 inches. More than .5 but less than 1 margin of stability (less than one caliber) and a rocket is "marginally stable'. More than two calibers of stability is known as "over stable". An over stable rocket will tend to dramatically turn into the wind. A marginally-powered, over stable rocket can end up almost horizontal.
Adjusting the Center of Gravity
To move the CG forward, add weight to the nose, lengthen the rocket, or lessen the weight in the aft end of the rocket. To move the CG aft, (for example, if your rocket is overstable), do the reverse.
Adjusting the Center of Pressure
To move the CP aft (more stable), increase the size of the fins. To move the CP forward, decrease fin size.
How Long is Too Long
A rocket must maintain its rigidity in flight. Any tendency to bend will be magnified in flight resulting in a kinked tube and likely a failed flight. If you hold a rocket horizontal by its tail section and notice any curvature in the rocket, your bird probably isn't stiff enough. Sorry, rocketeers, Viagra will not cure this problem.
Sizing the Motor
In selecting a motor to power your rocket, you need to have at least a 5:1 thrust to weight ratio. See a detailed discussion of this guideline Motor Selection in the PROPULSION area.
Launch Rod Diameter
Determine by motor size:
A,B,C - 1/8"
D,E - 3/16"
F,G,H and a body tube less than 2.6" - 1/4"
F,G,H,I w/ 2.6" to 4.0" body - 7/16"
I,J - 1/2"
Over J and body tube over should use rail buttons
Minimum Speed for Stable Flight
44 fps (30mph) is generally accepted as a minimum safe speed for stable flight. Faster speeds are necessary to achieve stability in windy conditions.
Mounting launch lug(s)/button/s
When mounting a single lug, cover the center of gravity with the lug. Always mount at least two rail buttons. When mounting two lugs or buttons, mount the lower piece at the rear of the airframe. The second should be on or just behind the center of gravity.
Submitted by Tom Savoie
Originally printed in Extreme Rocketry Magazine
Rocketry is one of those things you do in life that has no in-between. You have either a complete success, or an unmitigated disaster. Every flight, including failures, is a new andunforgettable learning experience. While some of the disasters can be attributed to bad or defective equipment or materials, a lot of failures can be attributed to incorrect preparation.
You certainly feel bad when you forget wadding in your Big Bertha, but it pales in comparison to forgetting something when flying your Big Kahuna. And the more we pay attention to the successes and failures of others and ourselves, the more we learn and the better our chances are for successful flights in the future.
Flights with a regular model rocket are basic. Wadding-parachute-motor-igniter-plug and you're off to get a launch pad. Mid- and high-power rockets are more complex, so more things can go wrong. The lack of proper preparation reminds me of one flight I saw. The rocket represented a considerable investment of time, effort and money for this person. The lift-off, boost and coast were perfect, and separation charge fired at apogee. However, during separation, everybody saw the one little "oops" this rocketeer forgot: to fasten the shock cord to both sections of the rocket. The upper part of the rocket came in under parachute, but the booster came in ballistic. Ouch.
Trying to document all of the possible ways to go wrong would fill a James Michner novel. Here is a small list of failures what I have either witnessed or been guilty of myself: All it takes is something like a forgotten O-ring in the motor and you get a CATO. Or there's not fastening the shock cord correctly and you get more pieces coming down than went up. Forgetting to arm the recovery electronics gets you a ballistic rather than parachute recovery. Using the wrong size launch rod will send your rocket off in unwanted directions, if it cleared the rod at all. Forgetting wadding turns your parachute into either a melted wad or the equivalent of a screen door, both bad for future flights. Not verifying your CG on assembly can turn your vertical flight into a horizontal one. That's not a good way to get the crowd to do the Wave.
Since we are all rocket scientists, I decided to take a "page" from the professional rocket scientists and write check-off lists, or "procedures" as they call them, for rocket preparation and launch evolutions. Even in the middle of the Apollo 13 disaster, everybody had a procedure for everything. If there wasn't one, you wrote it to make sure everybody was clear on what they needed to have and what they were supposed to do. This made sure everybody was "on the same page."
Procedures are essential to a person like me. I would forget my head, as the saying goes, if it wasn't permanently attached. I run down a procedure to make sure I don't forget something every time I leave the house. If I didn't, I would leave at least one essential thing behind, every time. I started using procedures years ago when I was SCUBA diving. It is embarrassing to get to the dive site and discover you forgot your weight belt, regulator or fins (or all of them) as I did on several occasions.
The source of my organization comes from my Palm Pilot. Not only do I use it to help keep me organized, I can also recover flight data from my onboard computer into it while on the flight line as well. I mention Palm specifically because there is a shareware program called HandyShopper that I use for these lists. I use the Aisle #'s as step #'s so that I can easily adjust the order of things in a procedure if I have to. In practice, after completing a step, I merely check it off, just like if I had just grabbed the bread or eggs. If you don't have a handheld computer, clipboards and paper served the professionals for years.
The best way to develop your own procedures is to sit in a quiet area and go through everything in your mind, start to finish. After you have imagined them, write them down and go through the list again. Then go and perform the procedure, adding notes and adding/changing steps as you go. As with all endeavors in our lives, your mileage may vary. The standard that you should aim for is that anybody can understand and complete your procedures. Imagine yourself in a full body cast with your jaw wired shut. A fellow rocketeer of approximate experience should be able to get you to the range, prep and fly your rocket without any "input" from you.
The first list is the material preparation procedure. You make sure your rockets are ready, double check you have everything, test electronics, dip a few igniters, whatever you need to do to make yourself ready. This will prevent the proverbial running around like a headless chicken the morning of the launch, which cuts into flying time. Doing this over an evening or two during the week gets you 90% ready. All you have to do the night before is quickly check everything before packing it into the car to make sure no one has "borrowed" something. I verify my range box, motor box, etc. are properly stocked by writing in the bottom or on the cover of every compartment what is supposed to be there, so anything missing jumps out you.
Next you can concentrate on the family. Lay out clothes for everybody, make sure your club ID's, cash for range fees and so on are on hand (preferably packed in your range box).
The next procedure is car-packing. The order that I use to pack the vehicle is the opposite of what I will need on the range. Things that have to come out first (tables, chairs, etc.) go in last. If you pack everything but food and drink the night before, you can do it calmly and you have the time and leisure to double-check and properly secure the items. You also make sure the vehicle is up to the job. Check the fluids, tires, gas and so on. If your alarm doesn't go off and you wake up late on launch day, you can jump into your clothes, dash out to the car and drive off, with the worst consequences being you have forgotten food, drinks and family members.
Once you are on the range and set up, you can relax a bit and take a break. Fly some model rockets, catch up with club members, volunteer as RSO/LCO for a shift, whatever. Your prior planning has given you this break.
Once you are ready to launch a big rocket, pull out its' pre-flight procedure. You will probably need an individual procedure for each of your HPR rockets. This procedure should take your rocket from cold (unprepared) to warm (ready for RSO and the launch pad). The number of individual steps is not important. Clarity of the steps is important. Thirty-seven steps to load and secure the motor into the rocket might be a bit of overkill, but you don't want to have just "stick it in and tape it down" either. Make sure your flight card is filled out, electronics are installed and ready, your CP/CG ratio is good and everything is connected and ready to go.
Now comes the final countdown. Get your rocket approved by the RSO, draw a pad from the LCO, and head out with the rocket and your final preparation procedure. Verify the launch pad can handle your rocket, put the rocket on the pad, insert the igniter, arm the electronics, take the rocket from warm to hot (ready) and head back to the range head to ready your cameras.
If you have invested the time in developing your procedures, you have eliminated 98% of human error on your part. You have done everything you could to ensure a safe flight that ends in a recovered rocket.
The investment of time you spend at home developing these procedures will save countless hours and rockets on the range. As the military puts it, "The more you sweat in peacetime, the less you will bleed in wartime."
Safe and successful flying!
Remember, the things you need FIRST go in LAST.