top of page

Groupe de Fitness

Public·81 membres
Demian Tretyakov
Demian Tretyakov

Isp System Starter 18


Of course, there are privacy concerns with an always-on camera and Qualcomm is taking them seriously. For starters, no data from this ISP will leave the device and it is protected by the new security features of the Snapdragon chip. Also, this feature will be up to OEMs to enable or disable and provide appropriate controls to the user.




Isp system starter 18



No it's not, they're too far from the barrier of physics for that to be a consideration, for starters Apple's big cores are notably more efficient than Cortex X1, and Apple's small cores are even more efficient than Cortex A55. I don't know about the ISP but it's easier to design efficient ISPs because they're more specialized circuitry.


I ran out of the 6-29-4 / Pow'r Pak and had to get some starter blends from the local fertilizer dealer. Your program yielded 202 bu/ac and the local fertilizer was 147 bu/ac. You have a great program ... you've helped me make a lot of money down through the years.


Qualifications: High School Diploma; completed at least two years of college; strong commitment to providing high quality programming for youth; have a passion for the arts; ability to work schedule of 3pm to 6pm Monday through Friday; good organizational skills; self- starter; ability to work independently; good interpersonal, verbal and written communication skills; the ability to plan, schedule and carry out activities; and the ability to work effectively


Qualifications: Bachelor's Degree in a human services field with one to three years of experience working with young adults or High School Diploma with three to seven years of experience working with young adults; a valid driver's license; good organizational and interpersonal skills; and a self-starter with ability to work effectively as a member of a team.


There are different size black powder motors, as shown in the picture below. For reference, the typical model rocket engine that comes with most starter sets is the 18mm diameter X 70mm long variety (shown 2nd from the left). If you want more power, you'd probably select a bigger motor, and if you have a small launch field, you might want to choose a motor with less power.


The Estes black powder motors come with standard Estes starters. You can also use Estes Sonic starters or Aerotech First Fire Mini starters as well, although they may require a 12V launch controller to ignite properly.


1-7 These are known as the "sugar" propellants. KNSU is the "classic" formulation, which I first learned about while reading Brinley's Rocket Manual for Amateurs way back in 1971. I used this propellant with great success for all my early rocket experiments. Original formulation presented in Brinley's book:Potassium Nitrate 60%Sucrose 40% KNSU standard formulation (65/35 O/F ratio):Potassium Nitrate 65%Sucrose 35% The original formulation has slightly lower performance, however, has an advantage of lower viscosity slurry when melted.Click for excerpt from Brinley's book(continued)Potassium nitrate-sugar was originally a development of Bill Colburn in the 1940's (see The KN-Sucrose Propellant -- A Historical Look Back). KNSB was developed in the late 1970's by the Belgian rocketry group VRO. KNDX was developed in the mid 1990's by the author. KNSU, KNSB and KNDX have been researched extensively by the author, including full characterization of their burn rate - pressure behaviour. KNFR was developed some years later, but has so far found limited usage due to its great affinity to moisture. The burn rate- pressure relationship for KNFR was found to be identical to that of KNDX, based on strand burner tests conducted by the author. KNER is a fairly recent development. As far as I am aware, Scott Fintel was the first person to develop and document the properties of this particular sugar propellant. KNER has some attractive attributes such as great resistance to moisture and slower burning rate than the other sugar propellants which can provide for greater volumetric loading. It is difficult to ignite, however (which makes it even more safe to make and use). Mannitol-based KNMN has been used successfully by a number of rocketry enthusiasts. Burn rate-pressure characteristics of both KNER and KNMN (as well as KNSB) were investigated by amateur rocketry researcher Magnus Gudnason for his Bachelor Thesis in Chemical Engineering Characterization of Potassium Nitrate - Sugar Alcohol Based Solid Rocket Propellants. Magnus's results indicated that the burn rate- pressure behaviour of KNMN is identical to that of KNSB. I am also aware of some research that has been conducted regarding the use of mixtures of sugars, such as sucrose and sorbitol.A sugar substitute, xylitol, has been used by the author to a limited extent, with good success. The main drawback is cost of xylitol, however, the KNXY propellant has benefits such as very low hygroscopicity and slower burning rate than most other sugar propellants. Xylitol also has the advantage of an exceptionally low melting point (92 degrees Celsius). KNSU, KNSB, KNDX, KNER, KNMN, KNFR and KNXY all use the standard 65/35 oxidizer/fuel ratio. There are two other variation of sucrose-based sugar propellants that have been developed in recent years and have been used with good success. James Yawn has developed a version deemed "RCandy" that is made by solution and recrystallization. A specific recipe for "cooking" the ingredients, which involves the addition of water, needs to be followed meticulously to drive out the residual water to achieve a "crystal mush" stage. Further heating leads to a putty-like consistency that is then packed into the rocket motor casing. The approximate formula is: RCandyPotassium Nitrate 59%Sucrose 29%Karo syrup 12%Rocketry enthusiast Dan Pollino developed a variation that he deemed "Flexifuel". Owing to residual moisture in the propellant, it remains flexible after casting and as such, has the advantage that the propellant can be case bonded. Dan used Flexifuel successfully in many rocket flights. FlexifuelPotassium Nitrate 65%Sucrose 18%Corn syrup 17%Ammonium Lauryl Sulfate 0.27% (supplemental) 8 RNX was developed by the author with research beginning in 2001. I was intrigued by the potential for a cold-cast propellant using potassium nitrate as the oxidizer after being given a sample slug of epoxy mixed with potassium nitrate by fellow rocketry experimenter Marcus Leech. When ignited, the slug burned in a slow but stable manner, and showed good promise. RNX consists of potassium nitrate, epoxy and red iron oxide and is a moderate-impulse propellant that has many positive attributes. Besides the obvious advantage of being cold-cast, RNX possesses good machineability, is relatively slow-burning and has great resistance to accidental ignition. Two variants were developed: RNX-57 and RNX-71V, differing primarily in the brand of epoxy used. RNX-57Potassium Nitrate 70%Epoxy, East Systems 22%Red Iron Oxide 8% RNX-71VPotassium Nitrate 68%Epoxy, West System 24%Red Iron Oxide 8% 9-12 Serge Pipko has done some innovative development work on enhanced performance sugar propellants. These four formulations are ones I find particularly interesting: K132Potassium Nitrate 59.1%Sorbitol 31.8%Aluminum Powder 9.1% K122Sodium Nitrate 66%Sucrose 33%Iron (III) Oxide 1% K123Sodium Nitrate 60%Sucrose 30%Aluminum Powder 9.1%Iron (III) Oxide 0.9% K137Sodium Nitrate 60%Sorbitol 30%Aluminum Powder 9.1%Iron (III) Oxide 0.9% 13 Zinc/sulfur was a popular amateur propellant during the 50's and 60's. Due to it's low impulse, safety concerns regarding working with fine powders and rapid and uncontrollable burning rate, it has limited contemporary appeal. The roar, bright yellow flame, and copious smoke does admittedly make for a spectacular launch. A typical ratio isZinc dust 67.1%Sulfur 32.9% The "Photuris B" rocket described in C.L.Stong's The Amateur Scientist utilized a 75% Zinc/ 25% sulfur mixture. More information on Zinc/Sulfur may be found in Brinley's Rocket Manual for Amateurs or Bill Colburn's The Micrograin Rocket. 14 Pyrotechnic "skyrockets" as well as Estes type of model rocket engines use blackpowder as a propellant. The latter has propellant in the form of a highly compressed pellet comprised of:71.8% Potassium Nitrate 13.45% Sulfur 13.8% Charcoal 0.95% Dextrin In the early 1980's, David Sleeter'sTeleflite Corporation published booklets on "building your own Rocket Motors" using various compositions of blackpowder as the propellant. These motors represented self-made versions of commercial rocket motors ranging in size from A3 to E30. This was followed in 2004 by his book Amateur Rocket Motor Construction which featured blackpowder motors as large as a two-inch diameter I65. These particular publications were well-written and highly detailed, with the motors apparently being quite successful. Interestingly, Teleflite blackpowder features little or no sulfur content, with one recommended "starter" formulation being: Potassium Nitrate 70% Charcoal 30% If sulfur is added to increase the burn rate, the recommended sulfur content is 3% (apparently, the higher the sulfur content, the more "temperamental" the motor):Potassium Nitrate 80.8% Charcoal 16.2% Sulfur 3.0% Blackpowder is a low-impulse propellant. 15 A successful ammonium nitrate composite propellant utilizing aluminum powder as fuel was developed by the author following extensive experimentation that began in 2004. The A24 formulation proved to be particularly successful, being utilized in both static test motors and flight motors. These formulations utilize neoprene (chloroprene) as a binder, extracted from contact cement. The grains are formed by compression using a hydraulic press. Specific impulse in the range of 200-215 seconds is typical. A24Ammonium Nitrate 68%Aluminum Powder 17%Neoprene 11%Sulfur 4% 16 CP Technologies has developed a composite propellant that is comprised of:Phase-Stabilized Ammonium Nitrate (PSAN) 60%HTPB (R45HT) 20% Magnesium, 260 mesh 20% By most accounts, this seems to be a good propellant that is reasonably simple to produce and gives good performance. A drawback is with the use of magnesium powder, which requires particular care in handling, and is quite expensive. As well, the AN is very hygroscopic, necessitating proper storage of the AN and finished grains. 17 Of all the polymers used for composite propellants, polyurethane has one of the highest heating values. As such, polyurthane may be used as a fuel without a thermic agent. According to one source I came across, a composition in the range of 85-90% ammonium nitrate and 10-15% polyurethane works well as a propellant. 18 An interesting formulation I came across in Jared B. Ledgard's Preparatory Manual of Blackpowder and Pyrotechnics, this formulation uses stearic acid (a.k.a. aluminum stearate), which is a white waxy powder, as a binder. The result is a "plastic-like" propellant that can be heat-cast. Performance is reportly good with a burn rate of 5-6 mm/second at 1000 psi. formulation #03-03-013AAmmonium Nitrate, anhydrous 70%Aluminum Powder 15%Aluminum Stearate 15% 19 The use of GE Silicone II (GE280) as a fuel/binder with AP as an oxidizer is discussed in the paper Silicone II -- a New Fuel and Binder for Fireworks by Ken Burdick (see Journal of Pyrotechnics #8, 1998). Intrigued by the potential use of a simple and commonly available binder for an AP-based propellant, a few years ago I started experimenting along these lines. Indeed, GE Silicone II does make a very nice binder and the resulting propellant cures fully into a hard rubbery non-porous grain. Potential drawbacks were found to be very high burn rate and high pressure exponent. As such, I experimented with the addition of ammonium chloride as a burn rate suppressant. This resulted in a good experimental propellant. AXP-AP1.10Ammonium Perchlorate 62.8%GE Silicone II 27%Ammonium Chloride 10%Lampblack 0.2% 20-21 Detailed information on making PBAN-based AP composite propellant may be found in Terry McCreary's book Experimental Composite Propellant. The oxidizer is ammonium perchlorate (AP), the resin is PBAN (polybutadiene), and the curative is epoxy. The addition of aluminum results in an increased specific impulse, as the reaction of aluminum (with steam in the exhaust) is very exothermic. A drawback with the use of PBAN is the requirement that curing occur at an elevated temperature (140oF) for several days. A typical starter propellant is:Ammonium Perchlorate, 200 micron 79.8%PBAN 16.4%Epoxy 3.6%Lampblack 0.2%Lampblack is an opacifier. Burn rate behaviour of AP-based propellants is primarily dependant upon oxidizer particle size. As such, care must be taken to consistently use the specified particle size. The starter propellant modified with aluminum is:Ammonium Perchlorate, 200 micron 70%PBAN 17.3%Epoxy 2.7%Aluminum powder 10% 22 HTPB has the advantage over PBAN of curing at room temperature. The uncured mixture is typically puttylike and packs nicely into a mould. Trapped air can be a problem, creating voids in the grain. Likewise, voids and bubbles can result from gases given off during curing (as a result of moisture absorption). Drawbacks also include the limited pot life once the curative has been added to the mixture. Quite a few ingredients may be required (binder, plasticizer, Tepanol, cross-linking agent, surfactant, burn rate modifiers, etc.) although this is not necessarily the case. Gordon N. Campbell's booklet How to Formulate and Process Composite Propellants, published by Propulsion Systems, provides detailed information on AP/HTPB based propellants intended for the amateur rocket builder, and which provides formulas for a number of AP/HTPB propellants. An example is: Procite AA6510o2:Ammonium Perchlorate, 400 micro 49.2%Ammonium Perchlorate, 200 micron 16.4%Aluminum powder 10%Oxamide (burn rate supppressant) 2%HTPB (R45M) 12.1%DOA (plasticizer) 5.7%Caster oil (cross-linking agent) 1.3%PDS-8R111 (anti-foam agent) 0.1%MDI (curative) 1.1%DDI-1410 (slow-acting curative) 1.7%TPB (triphenylbismuth, cure catalyst) 0.4%Retired rocket engineer and fellow experimenter Harry Lawrence (who is teaching me just about everything I know about AP/HTPB propellants!) has a more simple formula that requires a minimum of additives. Harry's basic aluminum-content formula: APX:Ammonium Perchlorate, 600 micron 10.8%Ammonium Perchlorate, 300 micron 38%Ammonium Perchlorate, 140 micron 27%HTPB 17%DOA (plasticizer) 2.5%P.MDI (curative) 1.6%Aluminum powder 3%Lampblack 0.1%It is worth noting that the composite formulations (both PBAN and HTPB based) result in propellants that deliver excellent performance, have good mechanical properties, and offer potentially long burn times. Aluminum-enriched composite propellants burn with a brilliant hot flame and it is really spectacular to watch a rocket take to the sky powered by such a motor. 23 Recently I developed an experimental AP-based composite propellant that utilizes epoxy as a binder. As a thermic agent, iron powder is used to good effect, based on a suggestion from rocketry enthusiast John Ashcroft (aluminum powder is another candidate). Finding a suitable epoxy to safely use with AP was a challenge, as many epoxies (such as West System) result in a hazardous compound rather than a safe propellant. NuLustre epoxy, which is a two-equal part (resin-hardener) system, produces a safe propellant, but must be cured under a pressure of approximately 400 psi to eliminate porosity, This is of essential importance to avoid rapid and violent disassembly of the motor. AXP-AP2.3Ammonium Perchlorate 70%Epoxy (NuLustre) 23.8%Iron Powder (atomized) 6%Lampblack 0.2%24 I have been made aware of a successful composite propellant which utilizes powdered PVC (polyvinychloride) as the fuel/binder, and AP as the oxidizer. The stoichiometric ratio is AP 79.3% and PVC 20.7%. Unfortunately, I do not presently have any additional information on AP/PVC compositions. 25 Apparently an early "sugar" formulation used by rocketeers in the 1960's, I read about this in The Encyclopedia of Space (an English translation of La Grande Aventure de l'Espace), one of my favourite books as a teenager. Click for excerpt from the book. 26 I have just recently developed a performance-enhanced version of KNSB, which utilizes potassium perchlorate as a supplemental oxidizer. This propellant is prepared and cast in an identical manner to standard KNSB, and features a fast burn rate and moderately high pressure exponent. KNPSBPotassium Nitrate 35%Potassium Perchlorate 30%Sorbitol 35%27 "Formula Two" from the booklet The Homemade Solid Rocket Engine published by Spartan Scientific consists of a propellant with the formulation:Potassium Nitrate 46%Aluminum powder 22%Sulfur 14%Charcoal 3%Polyurethane 15%When I encountered this formulation back in 2004, I was skeptical. I could not imagine a propellant with such a low percentage of oxidizer. I mixed up a small batch and to my surprise, it burned very well with a hot white flame. 28 This formulation was under development by the Aurora Project Group for their sounding rocket project. The experimental propellant consisted of Potassium Perchlorate oxidizer, epoxy binder and red iron oxide. Following successful small scale motor firings, a large motor utilizing a cast grain with a star-shaped core was test fired. The motor CATO'd and work on this formulation was discontinued. Potassium perchlorate formulations are known to suffer from a high pressure exponent. This was likely a factor that led to the unexpected CATO. 29 Brinley's book describes an advanced amateur rocket (being built at the time) that utilized 100 lbs. of propellant consisting of 75% potassium perchlorate and 25% asphalt. GALCIT 61-C used in commercial JATO units consists of the following formulation:Potassium Perchlorate 76%Texaco No.18 asphalt 16.8%SAE No.10 lubricating oil 7.2%The asphalt is liquified at 275 degrees F. and pulverized potassium perchlorate blended in.30 A successful research propellant based on potassium perchlorate with a polyester binder is described in the technical report FTD-HT-66-730 Solid Rocket Propellants by Krowicki & Syczewski. The polyester binder is Polimal 110 (55% Polyester/45% Styrene). The formulation is:Potassium Perchlorate 73.6%Polyester/Styrene 26.4%This propellant is fast burning and has a high pressure exponent. As such, grain configuration with this propellant must have a neutral burn configuration, for example, tubular grain burning on core and outer surfaces (with ends inhibited). Reported Isp=168 seconds at 2300 psi with Kn=267.31 A successful dual-oxidizer propellant that utilizes two-part silicone as a binder was developed by Dave from Australia. Burn rate reported to be 8 mm/sec at 500-600 psi. Recommended Kn is 300-330. This propellant was used in an 8


À propos

Bienvenue sur le groupe ! Vous pouvez entrer en contact avec...

membres

bottom of page