The Utah Rocket Club's official schedule is set and is available on the website for your viewing pleasure. Among the changes from last year, the club has reduced the number of member meetings in favor of quality over quantity. While the club does have some very good presentations throughout the year at meetings, if a specifc presentation is not planned the meetings are very administrative and not very interesting to the general membership. So, some of the monthly meetings have been deemd Administrative and will be for the officers and board members to plan activities and address issues. Members are still more than welcome to attend but should not feel obligated to do so.
An additional launch date after HellFire has been added to the schedule and an additonal Sport Competition has been added to the first half of the year. There will be additional workshops, contests and other events added to the calendar as they are confirmed.
We hope that these changes to the club's activity schedule continue to improve the overall enjoyment of our members.
UROC's upcoming launch for October 14 is a go. We anticipate the launch only taking place on Saturday (Oct 14) as opposed to a two-day launch due to the low temperatures but it looks like we should have a pretty good day. A porta pottie will be onsite and the trailer is expected to roll in around 830am or so on Saturday morning. The more folks we have to help set the equipment up the quicker we can get flying. We do expect winds to increase later in the day so the earlier we can get the launch system up and running the more flight time we will have.
It's safe to say that Halloween is many people's favorite holiday. This appears to be the case with Mitch. He has come up with a couple of contests for us to participate in at the UROC Launch in October (14 and 15) to get us all in the Halloween spirit.
1. Best Halloween themed/decorated rocket - Entries will be judged first. The highest ranking rocket to successfully fly safely is the winner. Mitch will be providing prizes for these contests (thanks Mitch!) Fiirst prize is two G motors. Second prize is a Quest kit.
We will also be holding a "Most Repeated Flights" Contest, basically, whoever has the most successful, safe flights with any one rocket during the October launch will win. Same prizes for this contest as for the Halloween contest (Thanks again Mitch!).
In the event that a minor wins the first in either contest, the motor will be presented to their parents or guardian.
We'd really like to thank Mitch for the donations and the great ideas for the contests and would very much like to ask everyone to participate. We've got a few weeks to go before the launch and really looking forward to some greatr competition!
This launch will be held as a two-day event if the weather is cooperative. We have permission from the BLM for overnight camping at the launch site. We invite members to camp out Saturday evening and take advantage of the great weather early on Sunday as well. This launch will be held under the Tripoli Research rules. Also be aware that only members of UROC are allowed to participate in the launch. If you are not a member you can sign up online or at the launch.
As always, we will need help running the launch, RSO, LCO, pad managers and lots of help setting up and tearing down the range. We do have a Porta Potty ordered for this launch. Set up is expected to begin around 8:00 am and we will fly in to the early afternoon or until the wind gets to be too strong and if the weather permits maybe start up some model rocketry in the evening.
Sunday morning should prove to be some excellent flying time. The range should be set up, ready to go long before the wind catches us.
If the weather conditions for the upcoming launch deteriorate or if the fire hazard becomes too high, we will try to notify everyone via our normal modes including the website, facebook, and twitter.
The Ken Eva Memorial Meet (KEMM) took place on Saturday, April 22 out at Frank Hunt Field. The weather was very cooperative and there was a fairly good turn out for the competition.
We had some scouts set up launch pads to handle their launches to gain their rocketry badges as well. There were 11 contestants in the competition and some great flights. Matt Goode was the meet champion followed closely by Bruce Bell.
Results for individual events are listed below. The next NAR competition event is Pioneer 2017 and it takes place Saturday, June 3 at Frank Hunt Field as well.
You can view photos from the launch in the UROC Gallery
|Place||Contestant||NAR Number||Section||Total Points|
|1||Team, Pod Bay Doors||T-201||523||2400|
|2||Team, Pod Babe Doors||T-202||523||1224|
|Place||Contestant||Number||Section||Prototype||Static||Flight 1||Flight 2||Total||Points|
|1||Bell, Bruce||20636||523||D-Region Tomahawk||570.0||98.0||66800||600|
|2||Goode, Matt||100903||523||Space Shuttle||470.0||140.0||61000||360|
|3||Bell, Sally||85169||523||IQSY Tomahawk||460.0||100.0||56000||240|
|1||Team, Pod Bay Doors||T-201||523||Sandhawk||600.0||100.0||70000||600|
|2||Team, Pod Babe Doors||T-202||523||D-Region Tomahawk||530.0||100.0||63000||360|
|Place||Contestant||Number||Section||Flight 1||Flight 2||Total||Points|
|1||Team, Pod Bay Doors||T-201||523||381||381||540|
|2||Team, Pod Babe Doors||T-202||523||88||88||324|
|Place||Contestant||Number||Section||Flight 1||Flight 2||Total||Points|
|1||Team, Pod Bay Doors||T-201||523||48||48||600|
|2||Team, Pod Babe Doors||T-202||523||20||20||360|
|Place||Contestant||Number||Section||Flight 1||Flight 2||Flight 3||Flight 4||Total||Points|
|1||Team, Pod Bay Doors||T-201||523||52||52||360|
|--||Team, Pod Babe Doors||T-202||523||SEP||0||0|
|Place||Contestant||Number||Section||Flight 1||Flight 2||Total||Points|
|1||Goode, Matt||100903||523||2.2% (88 s)||22||300|
|2||Redd, Randall||6333||523||12.2% (101 s)||122||180|
|3||Snaufer, Mark||29609||523||46.7% (48 s)||467||120|
|4||Steele, Carrie||78080||523||68.9% (28 s)||689||60|
|4||Steele, Cassidy||81474||000||68.9% (28 s)||689||60|
|4||Steele, Katie||80121||000||68.9% (28 s)||689||60|
|5||Steele, Cody||46810||000||77.8% (20 s)||778||30|
|6||Stewart, Pearce||101610||000||87.8% (11 s)||878||30|
|1||Team, Pod Bay Doors||T-201||523||CAT||67.8% (29 s)||678||300|
|2||Team, Pod Babe Doors||T-202||523||CAT||78.9% (19 s)||789||180|
The first UROC launch for 2017 was held on Saturday, March 18 and into Sunday March 19. We had a good number of people attend over the two days and in general the launch was a success. We had the trailer onsite Friday night so we were ablle to begin setup early on Saturday morning. We had a good number of helpers to carry pads out, set up the range marking and wire the control system. The launch was set up as a Tripoli Research launch and we had pads set up for Model Rockets up to non-complex M motors. The largest motor flown over the weekend was an L and it was a succesful flight. FAA coordination was handled by Jim Yehle and went smoothly. Our waiver was open from 8am to about 5pm on Saturday and until we closed up operations on Sunday around 2pm.
Overall the launch was great, highlights included beautiful weather on Saturday and Sunday morning. Of course wind picked up around 12:30 and lasted most of the rest of the day Saturday. It was never strong enough not to be able to launch but folks were tired and the night launch just didn't happen. We had a good number of people camping out on Friday and Saturday night in rigs ranging from tents to big fifth wheel RVs. Everyone had a great time talking, listening to music at cooking meals.
If you attended the launch and have some photos or videos you like to share please submit them to the website.
HellFire, sponsored by the Utah Rocket Club (UROC) takes place this year August 3,4,5,6. Though HellFire is technically an amateur launch, we’re talking serious rocketry here. Participants from around the country launch rockets ranging from foot-tall wonders to towering monsters that weigh in at over one hundred pounds, feature high-tech electronics, use a propellant similar to that used on the space shuttle, and lift off with 750 pounds of pure thrust.
Now in its 22nd year, HellFire continues to grow. Many people attend not to launch, but simply for the thrill of watching. Between launches, visitors enjoy examining rockets and components close-up and speaking with the experts who build and launch them.
Spectator Admission to HellFire is free and the public is welcome. HellFire will be held on the Bonneville Salt Flats near Wendover, Utah. Take Exit 4 on Interstate 80 and follow easy-to-spot signs. The event takes place 9 a.m. to 5 p.m. Thursday, August 3 through Sunday, August 6.
Discounted registration for flyers is available for UROC members.
Many more details to come over the next weeks.
Tips for visitors:
UROC's planned NAR Sport Launch scheduled to take place on March 21st appears to be a go! UROC President Ken Park recieved notification from the BLM SLC Field office that the launch site has been cleaned up and our documentation is in place. Additionally, the FAA waiver is in place and will be activated if the launch commences. The weather appears to be cooperating for this launch and we will continue to update the UROC.org website with any further news or announcements regarding the launch.
It's time to get out there and fly!
UROC president Ken Park recieved a phone call today from the BLM agent responsible for taking care of the recent toxic waste spill at our Frank Hunt Field launch site.
The agent reported that the clean up is already in progress and they fully expect the launch site to be available for our February 21st Research Launch! This is much faster than any of us expected. Of course things change so please watch this site for further details and updates about the upcoming launch.
UROC would like to thank the BLM Salt Lake Field office for responding to this issue as quickly and professionally as they have. We really appreciate their support and assistance!
With this new, the new 2015 flying schedule will be posted to the website shortly. Stay tuned!
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