From: buzz@rsd.dl.nec.com (Buzz McDermott)
Subject: Frequently Asked Questions, Part 2 (of 2)
Keywords: FAQ
Organization: NEC America, Radio Software Dept
Date: Mon, 5 Oct 1992 17:04:00 GMT
Expires: Sat, 7 Nov 1992 15:00:00 GMT

Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 2 of 2

[last modified: 03 Oct 1992]

This is the second of two parts of the rec.models.rockets FAQ.  Comments,
corrections, and suggestions are encouraged and may be sent to Buzz McDermott
at buzz@rsd.dl.nec.com.

----------------------------------------

Section 6: Competition

6.1 I would like to get into competition.  I would prefer to start with kits
    rather than designing and building my own.  Are there any manufacturers
    making kits specifically designed for competition?

    There are several sources of kits designed primarily for competition.
    Some of the manufacturers are:

      Apogee Components                    1/2A-C: SD, PD, superroc, eggloft;
      19828 N. 43rd Drive                  specialized competition motors
      Glendale, AZ 85308                   Catalog: $2
      (602) 780-2WIN

      North Coast Rocketry                 Helicopter, B/G, R/G,
      4848 South Highland Dr, Suite #424    piston launcher
      Salt Lake City, Utah 84117           Catalog: $3
      (800)877-6032 (voice or Fax)

      Qualified Competition Rockets        A number of competition designs and 
      c/o Kenneth Brown                    kits for model rocketry
      7021 Forest View Drive               Catalog: SASE
      Springfield, VA 22150

    The manufacturers list described in 'Other Sources of Information' 
    contains many additional addresses.

6.2 What are the major categories of competition model rocketry?

    The NAR sanctions model rocketry contests throughout the USA, and 
    throughout the year.  The contest year runs from July 1 - June 30.
    The final contest for a given contest year is NARAM, usually held 
    in August, after the end of the contest year.  The complete list
    of event and rules for model rocketry may be found in the NAR 'Pink Book',
    available free to NAR members and may be ordered from NARTS.  
    Some of the event types are:

    - Altitude (1/4A - G)
      The purpose is to get the maximum altitude from a model using a
      specified class of engine.
    - Streamer Duration (1/4A - G)
      The purpose is to get the maximum flight duration from a model with a
      specified engine type using streamer recover.
    - Parachute Duration (1/4A - C)
      The purpose is to get the maximum flight duration from a model using
      a specified motor type.
    - Eggloft Altitude/Duration (B - C, D - G)
      In this event the competitor must launch either one to two large raw 
      hen's eggs, depending on engine type, and recover it/them, intact, 
      crack free (B-C with single egg, D-G with two eggs).  The goal is either
      to reach the highest altitude or have the longest duration flight, 
      depending on the event.
    - Rocket Glider and Boost Glider Duration (1/4A - G)
      In these events the competitor launches a glider using a rocket engine
      and tries to achieve the longest flight duration of the glider.  In 
      boost glider the pod containing the motor may be ejected and recovered 
      separately.  In rocket glider all parts, including the expended engine,
      must stay with the model (1/4A - G).  There are categories for single
      wing, flex/swing wing, and multi-wing gliders.  Rocket glider is 
      generally considered the more difficult event because the model must be
      both a rocket and a glider without loosing any parts.  The CG and CP 
      requirements for the two phases of flight are very different.  There
      is also an R/C rocket glider event.
    - Helicopter Duration (1/4A - G)
      In these events the model ascends as a rocket.  Rotor arms then extend
      by some mechanism and the rocket slowly descends like a helicopter which
      has lost power.
    - Payload Altitude (A - G)
      In these events the competitor must launch one or more standard NAR pay-
      loads (1 ounce each of fine sand) and recover the model.  The number
      of payloads increases with larger engine sizes.
    - SuperRoc Altitude/Duration (1/2A - G)
      These events require VERY LONG rockets (7-8 feet and more).  There are
      both altitude and duration variations.  The trick to these events is
      that the model must be recovered and the body tubes MAY NOT BEND OR 
      CRIMP.
    - Scale Events
      These are craftsmanship events where competitors build scale models of
      real military or commercial rockets.
      * Scale: exact replicas of space vehicles, with measurements and scale
        checked VERY carefully
      * Sport Scale: craftsmanship is judged, but less strict scale measure-
        ment checking
      * Peanut Scale: Sport Scale for small (<30cm long, <2cm dia.)
      * Giant Scale: Sport Scale for large models (>100cm long, >10cm dia.)
      * Super Scale: must include a scale launcher as well as model of
        rocket; judged same as scale
      * Space Systems: must include launcher, model of rocket, and launch
        a flight with payload, predict altitude, launch within a time window,
        and land within a target zone. Judged same as Sport Scale (launcher
        is optional but gets bonus points).
    - Plastic Model Conversion (PMC)
      This event is either loved or hated.  Competitors enter plastic models
      of rockets or other aero-vehicles that have been converted to fly as
      model rockets.  The models are judged on craftsmanship, degree of diffi-
      culty, and flight characteristics.
    - Precision Events
      These include spot landing, random duration, predicted duration, 
      precision duration, and predicted altitude.  The competitor is given a 
      flight duration or altitude to try and match as closely as possible, 
      or must predict the altitude or duration, depending on the event.  In 
      spot landing the goal is for the model to land as closely as possible 
      to a marked spot on the ground.
    - Drag Race
      Multi-round, elimination tournament where contestants gets points
      for:
      * FIRST lift off
      * LOWEST altitude
      * LAST to land
    - Research and Development
      A non-flying event where contestants enter results of research projects.
      Entries on judged on completeness, contribution to rocketry knowledge,
      degree of difficulty, etc.

    The Tripoli "Member's Handbook" currently lists two competitive events for
    high power models:
 
    - G Motor Waterloft Duration/Altitude
      The purpose of this event is to either get the maximum altitude or max
      duration from a G powered rocket lifting 16 fluid ounces of water as
      a payload.
    - H Motor Streamer Duration

6.3 What are some good events to try when first getting into competition?  Any
    'sage' advice?

    From buzz@rsd.dl.nec.com (Buzz McDermott):
    I just started competition this year.  I must have asked 30 experienced
    competitors where to start.  I got 30 COMPLETELY DIFFERENT ANSWERS!!
    They ranged from 'keep it REAL simple' to 'try everything'.  Here is
    a summary of the most prevalent advice.  It seems to have worked for me.

    - Competition requires a large stable of rockets, given all the
      possible events and engine categories; start with some of the 
      simpler ones where a single model might be competitive in more
      than one event (for example, the same model might be used for 1/2A-A
      streamer or parachute duration, another model might be competitive in
      any of A - C stream or chute duration)
    - Try single eggloft (B-C, duration or altitude) before trying the 
      multi-egg categories (such as D or E dual egg).
    - Go for a good, qualified flight first; then decide if 'going for
      broke' is appropriate on your second flight (this is for mutli-
      flight events).
    - Get a teammate and enter as a team.  There are too many models you
      need to compete to be able to build all of them your first year.
      Entering as a team let's you pool time, talent, experience, and
      models.
    - Don't get discouraged if you aren't immediately competitive.
      Remember, the main goal is to enjoy yourself and HAVE SOME FUN.
    - KEEP A LOG OF ALL FLIGHTS.  RECORD WHAT WORKS AND WHAT DOESN'T.
      NOTE YOUR FLIGHT TIMES, ALTITUDES, ETC.  Your biggest weapon
      in many events is in being able to predict how your models
      will perform.
    - Make a model preparation checklist for each event (i.e., a detailed,
      step-by-step list of everything necessary to prep the model).  Use this
      list for your first few competitions.  Comp models are often prepared 
      a little differently from sport models.  The difference between winning
      and losing is often just attention to detail, or lack of it, in the
      heat of competition.

----------------------------------------

Section 7: Scale Modeling

7.1 I would like to make a scale model of the <??> rocket.  Where do I start 
    looking for technical data, dimensions, flight substantiation data, etc.?

    Two places to start looking would be Peter Alway's book of scale data.
    Another source is the list of scale data sources maintained by Kevin 
    McKiou and posted periodically to this newsgroup.  Refer to the section 
    'Other Sources of Information' in this FAQ for more details on these.
    
7.2 I've never built any scale models.  Are there any recommended kits for 
    first timers?

    The following recommendations have been made by posters to r.m.r:

    For A-D powered rockets:
      Estes IRIS (A-C power, sport/semi scale)
      Estes Black Brandt II (D power, sport/semi scale)

    Larger models:
      North Coast Rocketry Patriot (E/F/G power, sport scale)
      Aerotech ISQY Tomahawk (E-G power, scale)

----------------------------------------

Section 8: On To High Power

Review:  A High Power rocket is a model weighing more than 1500 grams (3.3 lb)
         or containing more than 125 grams of propellant (or any motor
         with more than 62.5 grams of propellant).  The NFPA has 
         recently ruled that any motor with more than 80.00NS of total
         impulse is a high power motor.  This last ruling is under
         review by the NFPA and CPSC.

         Medium power rockets (E, F, and G) are, technically, model 
         rockets according to the NAR definition, but any of these weighing 
         more than 1 pound fall under the same FAA restrictions as high 
         power models.  Many cities still limit 'model rockets' to those 
         weighing less than one pound, as well.

         Advanced rockets are high power rockets weighing more than 3.3 
         pounds and/or containing more than 160NS of total impulse.

8.1 I'm a successful model rocketeer.  What do I need to get into HPR?

    When this question was posted to r.m.r a while back, these were the pre-
    dominant suggestions and tips:

    - Start with E/F/G kits with 29mm motor mounts from LOC or Aerotech. 
      These should be the easiest to build.
    - Get familiar with and use expendable motors before jumping into
      reloadable technology.
    - Join a high power club if possible (local NAR section or Tripoli 
      prefect).
    - Be very careful of the construction differences between model and high 
      power rockets.  You HAVE to build higher power rockets to be more sturdy
      than model rockets (see the next question).
    - If not already a member, join both the NAR and Tripoli (if you can 
      afford high power rocketry, you can afford to join and support both
      these organizations).

8.2 What are the major differences between model and high power rockets, 
    besides size and engines?  Are they built differently?

    Above and beyond all else, high power rockets are built much stronger 
    than standard model rockets.  This is due to the higher speeds and 
    acceleration achieved by these models.  Some of the construction 
    differences are:

    - High power rockets have stronger, thicker body tubes
    - They have MUCH stronger engine mounts, bonded using epoxy rather
      than white or yellow glue
    - Engine mount rings, adapter rings, etc., are typically made from
      1/8" or thicker aircraft plywood, rather than paper or balsa
    - Fins are typically made from plywood or waferglass, not balsa;  (thick)
      balsa fins have been used on E and F powered models, but they have to
      be heavily reinforced
    - Fins are often mounted directly to the engine mounts through slots
      in the body tube (TTW mounting)
    - Parachutes are larger and typically made from some type of fabric 
      (plastic chutes are not strong enough, usually)
    - Heavy elastic shock cords with steel braid or Kevlar shock line 
      are used rather than rubber for shock cords, and these are typically
      epoxied to the motor mount or a bulkhead

8.3 Are there any national organizations to which I could join?

    There are two national organizations associated with high power rocketry.
    The first is the NAR.  It supports both model and high power rocketry.
    The second is the Tripoli Rocketry Association, which was formed by NAR 
    members who felt the NAR was taking too much time getting a high power 
    program together.  Tripoli is oriented more towards high power 
    rocketry.  Both organizations offer certification programs for individuals
    wishing to purchase high power engines.  Anyone wanting to get involved
    with HPR is encouraged to join one or both organizations.   The addresses 
    for both are in the section 'Some Commonly Sought Addresses'.

      National Association of Rocketry
        -sanctions contests
        -insurance for rocket flying activities
        -American Spacemodeling magazine
        -high power certification
        -engine certification
        -sanctions high power rocket launches
        -dues: $25/year (senior)

      Tripoli Rocketry Association
        -High Power Rocketry magazine
        -sanctions high power rocket launches
        -high power certification
        -dues: $40/year

8.4 What is the current legal status of HPR motors?  I've heard the NFPA has
    banned them.  Is that true?

    Type G rocket motors (80-160NS) are currently classed as 'banned
    hazardous substances' by the Consumer Product Safety Commission.
    H and larger motors do not fall under CPSC jurisdiction and may be
    purchased and shipped as Class B explosive devices, with restrictions
    on method of shipment, etc.  These motors must be used in compliance
    with the NAR and Tripoli high power safety codes.

    The NAR is actively pursuing relaxed regulations.  Pat Miller, the
    president of the NAR, recently met with NFPA and CPSC representatives
    and offered the suggestion that CPSC should alter its classification
    of G rocket motors to place them in the same class as accepted earlier
    by the NFPA (i.e., Class C Toy Propellant Devices).  The NAR and
    Tripoli are both working to insure that reloadable engine technology
    remains available to the hobby.

    YOU MUST BE A CERTIFIED MEMBER OF A QUALIFIED ORGANIZATION TO PURCHASE OR
    USE CLASS B EXPENDABLE MOTORS.  See section 8.9, below, for information
    on becoming certified to use Class B motors.

8.5 What is a 'reloadable' motor.  Are they worth the price?  Are they legal?

    A reloadable rocket motor is a metal cylinder with screw-on end pieces.
    Solid propellant and time delay are purchased separately from the motor 
    casing, in 'reload kits'.  These kits contain all of the expendable,
    non-reusable materials for a single flight.  The cost of the reload is 
    significantly less than the cost of an expendable motor (when talking 
    about F sizes and up).  Reloadable rocket motors are not currently 
    banned by the NAR.  They are prohibited from competition at this time, 
    though.  Use of reloadable technology is currently restricted by the 
    NFPA to individuals belonging to qualified organizations.  The NAR and 
    Tripoli are qualified organizations.
 
    Reloadable motors' status is under review by DOT and CPSC. Shipping 
    propellant slugs is currently illegal per DOT.  Purchase of reloads
    is legal, however, given that the purchaser is properly certified to
    purchase and use the motors.  Aerotech its parent company, ISP, have 
    stopped shipping all reloads until the DOT matter is cleared up.

    Reloadable motor kits and reloads are now predominantly available at
    high power launches, via distributors selling on the launch site.
    The recent DOT ruling has dried up the discount mail order sources for
    reloads, but even when purchased at launches (even if bought at near
    suggested list price) reloads are very cost effective compared to the
    cost of Class B expendable motors.

    YOU MUST BE A CERTIFIED MEMBER OF A QUALIFIED ORGANIZATION TO PURCHASE OR
    USE RELOADABLE HIGH POWER MOTORS.  See section 8.9, below, for information
    on becoming certified to use high power reloadable motors.
  
    WARNING: IT IS HIGHLY RECOMMENDED BY r.m.r CONSENSUS THAT YOU DO NOT 
             ASSEMBLE AND/OR PREP A RELOADABLE-TYPE MOTOR UNTIL JUST PRIOR 
             TO ITS USE (I.E., ON THE FLYING FIELD). *** UNDER NO 
             CIRCUMSTANCES SHOULD ASSEMBLED RELOADABLE MOTORS BE STORED WITH 
             IGNITERS INSTALLED ***

8.6 What are these different 'types' of composite motors I hear about (White
    Lightning, Black Jack, Smokey Sam, etc.)?

    These are all manufacturers' names for various formulations of 'stuff'
    they have added to the propellants to get specific pyrotechnic effects.

    White Lightning (Aerotech): medium average thrust engine producing a 
      bright white flame and distinctive roar.
    Black Jack (Aerotech): low(er) average thrust engine which produces a
      dense, dark exhaust to aid in tracking.  Also has a distinctive roar.
    Blue Thunder (Aerotech):  high level average thrust engines with a bright
      violet-blue flame and very little visible exhaust.  Designed for high
      thrust, high acceleration lift-offs.
    Smokey Sam (Vulcan): produces a dark exhaust to aid in tracking.
    Silver Streak (Rocketflite): produces a fine shower of white sparks during
      boost (I understand that these are actually black powder motors).
    Hellfire (Rocketflite?): a high thrust motor which produces a bright red
      flame (also a black powder formulation?).

8.7 What's an FAA waiver? Which rocket flights require one?

    An FAA waiver is official permission by the Federal Aviation Administra-
    tion allowing the launching of rockets exceeding a certain size.
    A waiver is required for all rockets weighing more than one pound, 
    containing more than 160NS total impulse in its engines, having more than
    4 total ounces of fuel, having any motor with more than 2.2 ounces of
    fuel, or using reloadable engines, into FAA controlled airspace.
    This airspace begins at 1200 feet for many metropolitan areas, but can 
    be as low as 600 feet around airports.  It is NOT legal to fly high 
    power rockets without this waiver.  You do not need a waiver for 'model
    rocket' (i.e., under 1 pound) launches.

    The Tripoli Rocketry Association publishes information on obtaining an
    FAA waiver in their `Members Handbook'.  Several high power manufacturers
    also publish this information.

    The FAA is currently considering a proposal by the NAR to exempt all
    models meeting the NAR definition of a model rocket (i.e., 1500 grams...)
    from requiring a waiver.  This is still just under consideration.

8.8 Is high power rocketry legal in every state, if the proper forms are
    obtained?

    No.  Even with an FAA waiver, HPR is NOT legal in every state.  Check 
    with your local fire marshal for requirements/restrictions in your area.
    The NAR is actively working to get state restrictions on model and HPR 
    removed.

8.9 I've heard that NAR and Tripoli both have a certification process for 
    using/launching HPR.  How do I get certified?  Am I required to be 
    certified if I want to fly HPR?

    First, you have to join either the NAR or Tripoli.  In the NAR program,
    you first successfully fly a G powered rocket in the presence of two
    NAR HPR certified members who witness your flight.  You fill in and
    mail a certificate (along with $5) to the NAR, which places your name
    in its computerized list and mails you a new license stating your new 
    certification level.  You now qualified to fly H rockets.  By 
    doing the same thing with an H rocket you can become qualified to fly
    I, and so forth.  You need to be certified for each new engine type.
    If you wish, you can qualify for several motor types prior to sending
    in your forms.  You may then send them in together and pay only a
    single $5 processing fee.  Also, as of August, 1992, you may use 
    clusters of motors to qualify for a particular impulse level (for
    example, you might cluster 2 'F' motors for your 'G' flight, or
    cluster 4 G42 motors (400NS total impulse) to get your 'J' certification.

    With Tripoli's 'Consumer Confirmation Program', you must successfully 
    launch and deploy the recovery system (you don't actually have to 
    recover) an H powered rocket in the presence of an Authorized
    Person (who these are is spelled out in the Members Handbook).  This is
    your 'confirmation flight'.  Your consumer card is filled out at the 
    launch and one part of it is returned to Tripoli.  You are then said to 
    have been 'confirmed'.

    Both organizations have 'grandfather' clauses to allow 'known HPR flyers'
    or members certified by the other organization to be certified without
    a confirmation or certification flight.  If you are Tripoli certified,
    (and an NAR member) you may send in your Consumer Confirmation card to 
    the NAR (along with $5) and you would become NAR 'J' certified.

    Finally, both organizations are continually reviewing their respective
    certification processes.  The description listed here might differ from
    the actual certification process at the time you attempt to certify.

8.10 Where do I find out the proper way to use HPR rockets and motors?  I'm
     familiar with the NAR Model Rocketry Sporting Code.  Is there an HPR
     equivalent?

    Both the NAR and Tripoli have HPR safety codes.  The two organizations
    are working together to produce a consistent safety code to be presented
    to the NFPA.  These codes specify minimum launch field sizes, minimum
    distance to keep from launchers, etc.  The NAR Interim High Power Rocket
    Safety Code has been published in AmSpac.  The Tripoli safety code is
    published in their Members handbook, which is sent to all new Tripoli
    members.  Everyone wanting to get involved in HPR is strongly urged to
    join one or both of these organizations.  In the near future, it may
    be a requirement before you can buy motors.

8.11 What are some good kits to build when first getting into high power 
     rocketry (assuming I have all of the basic model rocketry skills)?

    From cdt@pdp.sw.stratus.com (C. D. Tavares):
    From WHITMAN@ISTP1.GSFC.NASA.GOV ((Rusty Whitman):
      NCR Big Brute

    From cdt@pdp.sw.stratus.com (C. D. Tavares):
      AAA Penn. Crude

    From dwade@jarthur.Claremont.EDU:
      I REALLY like the Aerotech line.  Easy to build, well constructed,
      (Great nylon chutes, through-the-wall-construction, all that good stuff)
      and pretty reasonably prices.  They're all E-G.  ISP has a similar line
      (the parent company).
      [NOTE: See Aerotech modification suggestions in 'Hints' section of FAQ]

    From: J.Cook@ens.prime.com (Jim Cook):
      LOC kits are a good introduction into high power - they are strong 
      (banging it several times for emphasis on the table).

8.12 Are there any (discount) mail order houses where I can get high power
     motors, kits and supplies from several manufactures, as well as save 
     some money?

    The following high power mail order houses were recommended by readers of
    r.m.r as a result of a request to recommend their favorites:
 
      High Sierra Rocketry
      P.O. Box 343
      Orem, UT 84059
      (801) 224-2276
      Catalog: $1.00

      Magnum Rockets, Hobbies and More, Inc.
      P.O. Box 124
      Mechanicsburg, Ohio 43044
      (513) 834-3306 (voice and FAX)
      Catalog: $2.00

      Rocket Research & Distribution
      8901 Milbrae Court
      Richmond, VA 23236
      (804) 330-4373 (voice and FAX)
      Catalog: $2.00

   Additional sources may be found in R. Michael Jungclas' list of 
   manufacturers and sources (which is posted periodically to r.m.r).

----------------------------------------

Section 9: Some Model and High Power Rocketry Records

[Note: This section will contain summaries of current national and 
       international records for model and high power rocketry.  I will 
       add to it as I can determine what the records are...Buzz]

The high power records come by way of a posting from Chip Wuertz 
(dlw@engr.ucf.edu).  Chip is part of the University of Central Florida's high 
altitude rocketry project.  This information is believed accurate and up to
date as of 20 July 1992.

    Records and Altitude Project Ideas

    (To set the records straight and answer some recient questions)


    * * Some current records for NON-METALLIC NON-PROFESSIONAL Rockets: * *

    Top two altitude holders:

    From: hrbob@ixstar.ih.att.com (R.E. Wiersbe)

    1) Altitude:  24,771 feet  (11.7% tracking error)
       Set by:    Chuck Rogers and Corey Kline
                  Lucerne Dry Lake Bed, Lucerne, Ca.
                  June 1989, USXRL-89

    2) Altitude:  22,211 feet   (5.3% tracking error)
       Set by:    University of Central Florida
                  BlackRock Dry Lake Bed, Gerlach, Nv.
                  August 1991, LDRS X

    Highest Tracked Flight at Lucerne:
       Kline/Rogers Team - 24,771 feet, 1989

    Highest Tracked Flight at BlackRock:
       University of Central Florida - 22,211 feet, Aug. 1991     

    Highest Tracked Staged Rocket:
       University of Central Florida - 22,211 feet, L750 to L750

    * Published notes on Chuck Rogers / Corey Kline Flight:
    (Lucerne Test Range Tracking Results, November 1988 - May 1989) -

    New unofficial altitude record for nonmetallamatuer high power/experimental 
    type rockets.  Possibly highest tracked flight of an amateur rocket
    (metal or fiberglass construction) yet in the United States.  Korey 
    Kline and Charles Rogers became the first recipients of the Rocket
    Newsletter perpetual altitude trophy for the first flight to exceed
    the previous record of 22,080 feet set with a metal rocket by the Fort
    Team in May 1984.  The trophy will be awarded to the next team to 
    exceed the current record.  Record is unoficial because of some 
    uncertainty on the exact track.  The cloud of red carpenters chalk
    ejected by the rocket was barely visible (because of a background of
    white clouds at higher altitudes) and high wind speeds at 25,000 feet
    dispersed the tracking cloud in only 3 - 4 seconds.  Trackers only
    got a track on the general vicinity of the red carpenters chalk
    in front of a cloud.  Before they could zero in the track, the red
    cloud had disappeared.  The angles from the last position of the tracker
    heads was used for the track, the error was only 11.7%.  The tracked 
    altitude was within 3.2% of the postflight prediction (25,567 feet)
    using the Rogers Alt4 altitude prediction program with the actual
    liftoff weight of the rocket, and a preflight CD estimation from
    program CD2.  Undoubtedly a valid track, but because of circumstances
    considered an unofficial record only.  The Rocket Newsletter considers
    this track an official record.  This rocket used a single, custom-manufac-
    tured L500-25, made by the Rogers/Kline team.
    
    *** Note: unofficial means Tripoli unofficial.  Tripoli only recognizes
       tracks with less than 10% error.  (Chip Wuerz) *************
    

    * Published notes on University of Central Florida's Flight:
    (The TRIPOLITAN ... AMERICAS HIGH POWER ROCKETRY MAGAZINE,
       OCTOBER/NOVEMBER 1991) -
    
    Highest tracked flight at LDRS-X / BALLS.
    Second all-time highest track of a non-metallic high power rocket.
    University of Central Florida's research project and altitude attempt
    to break the current high-power rocketry altitude record of 24,771 feet
    set by the KLINE/ROGERS team in 1989.  Altitude attempt had been based on
    3850 NS L-engine, new Vulcan L-750 engines deliver 3,000 (now known to be
    less from motor testing results) newton seconds.  In an attempt to make
    up power loss and to provide margin on the goal altitude of 25,000 feet,
    the upper stage was delay-staged by several seconds.  Altitude predictions
    computer simulation program predicted 28,500 feet.  Upper stage flew 
    substantial trajectory, reaching apogee nearly 2 miles downrange.
    Rocket used microprocessors / timer-controlled staging and ejection,
    on-board flight data measurement package, and a radio beacon system to 
    locate upper stage.  Track was accomplished using red carpenters chalk.  
    Both stages were recovered.
    
----------------------------------------

Section 10: Construction and Finishing Tips

    This section includes tips and suggestions on various topics having to do
    with construction and finishing techniques.  These have been posted to 
    r.m.r or mailed to the moderator by way of r.m.r request.

    Cutting, Sealing, Attaching Fins
    --------------------------------

    From J.Cook@ENS.Prime.COM (Jim Cook):
      Skip using glue W/ balsa dust, dope, or any other junk for filling the 
      grain in balsa fins or nose cones.  Use Elmer's "Fill 'n Finish" diluted
      with water to a thick paint (like white glue is) and paint it on.  
      Non-toxic and a coat or two will do.  Use Elmer's "Carpenter's Wood 
      Filler" thinned similarly to fill the spiral in body tube.  Both come 
      in a white plastic tub with an orange lid.  Note - the latter is 
      harder to sand, so don't make the mistake of using it on balsa as it 
      will require a lot of sanding.

    From: utidjian@remarque.berkeley.edu (David M.V. Utidjian):
      To fill the grain in balsa fins and fill in the spirals in body tubes 
      use epoxy. I use HOBBYPOXY "Smooth 'n' Easy" Epoxy finishing resin.
      For fins it does the trick in one coat... and sands easily... and
      adds strength to the fins.  I use those disposable brushes with the
      metal handles and brush on a single coat after a preliminary sanding.
      I then use auto body primer filler in gray and red-brown from spray
      cans for the entire model.  This gives very thin and even coats. I
      alternate the colors of the coats to show where the low and high spots
      are.  My last sanding before paint is done with 400 grit wet/dry paper
      and I do this wet... being careful not to get any inside the body tube.
      [Another good coating-type epoxy is PIC 'Coating Poxy'...Buzz]
      [NOTE:  This is not for kids or the inexperienced!! This technique is
      used in HPR where the added weight is not a penalty: Buzz]

    From Bob Turner (NAR member, not on net):
      Bob Turner (the DARS NAR section advisor) suggests using alcohol in
      smoothing 'coating' type epoxies.  The PIC 'Coating Poxy' instructions
      suggest using your fingers to 'burnish' any surfaces (i.e., fins) filled
      with the coating poxy.  Bob suggests using a VERY soft cloth which has
      been dipped in alcohol to rub the fins after about 30 minutes (or
      whenever the expoxy starts to set and is just slightly sticky to the 
      touch). [I followed Bob's suggestion and got MUCH smoother fins over
      the hand/finger burnishing method...Buzz]

    From cdt@pdp.sw.stratus.com (C. D. Tavares):
      Fill your fins BEFORE attaching them.  (Don't fill the root edge).

    From: jack@rml.com (Jack Hagerty):
      When sanding fins, or any other balsa part that you want to be all
      uniform, stack the parts together, even them up the best you can 
      (you'll be surprised at how uneven those die-cut pieces are!) on 
      the root edge and drive a couple of straight pins through them to 
      hold the stack in registration while sanding. For larger fins,
      anything over about 2 sq in, use three pins. I find that the pins
      that come in shirts are just about the right size. The small holes 
      that are left when you remove the pins are easily filled during the 
      sealing/filling step.

    From: kaplow@pobox.enet.dec.com (Bob Kaplow)
      I've found two handy tools for sanding big rockets. 3M makes these
      sponge-like sanding pads. They are great for conforming to the
      curves of tubes, nose cones, fillets, etc., and make quick work of
      fillers. The second is a palm sander, just like Norm uses on TV. Big
      rockets call for heavy duty solutions. Save the belt sander for
      airfoiling the fins during construction. 

    From: utidjian@remarque.berkeley.edu (David M.V. Utidjian):
      [To hold fins in place and aligned while drying I bought an Estes
      fin alignment kit].  At 15-16 bucks it seems a bit
      expensive but is well worth the aggravation and time it saves.  You
      can even make your own if you are handy.  I just set up my body tube
      in the jig and then check the alignment of all of the fins to the body
      tube. Then I use a thin bead of 5-min. epoxy. and in ten minutes I am
      done.  When I do the fillets I can do them all at once but don't have
      to worry about the softening the glued on fins so they droop.  You
      still have to lay the model on its side though but only for 5 minutes.

    Condensed thread on filleting fins; many contributors:
      First, ALWAYS fillet high power fin joints, even fins mounted TTW to 
      the motor mount.  This will add strength and improve the aerodynamics
      of the model.  The suggestions for filletting material include:
        * 5 - 30 minute thick epoxies
        * 30 minute (or longer) thin epoxy mixed with micro-balloons
          until it has athick, paste-like consistency; let it thicken
          some prior to using it
        * SIG Epoxilite (warning: this got very mixed reviews)

      Always keep a bottle of rubbing alcohol handy when working with epoxy.
      Dip your finger in the alcohol and run it along the fillet to smooth
      out the bumps.  It was mentioned that a pure epoxy 'topcoat' was 
      necessary on top of the epoxy/micro balloon mixture, although using
      an alcohol-soaked finger to smooth the micro-balloons might eliminate
      the topcoat requirement.

      Use 30 minute epoxy with microballoons added. Let it sit for a few 
      minutes in the pot so it thickens, and then apply it. The microballoons 
      make it much less runny, so you don't have to keep watching the fillet 
      to make sure it's not dripping or running around the edges. Also do one 
      side of two fins at a time:
              \          / 
               \        /     f = fillet, ^ = really bad version of body tube
                \f    f/      / and \ = fins
                 ^^^^^^

    Body Tubes (Cutting, Joining, Filling)
    --------------------------------------

    From cdt@pdp.sw.stratus.com (C. D. Tavares):
      [On cutting Estes-style body tubes]
      The simplest and best I ever used was Howard Kuhn's jig from the old CMR.
      It's a simple piece of wood L-angle moulding, with a notch for a razor
      blade cut into one side (from the wing toward the elbow) at one end.
      The only other parts are a wood block and a large black spring clip (the
      kind you hold really thick reports together with).  If you want, say, a
      6" piece of tubing, you set the block 6" away from the razor notch and
      clamp it there with the spring clip.  Now lay the tube down the L-angle,
      butting it up against the wood block.  Insert the razor blade, press
      lightly, and turn the tube.  (Put a dead engine into it if the tube is
      the right size to fit one.)  Three to six turns, and you have an edge
      that looks factory-cut.

                       ----
                      (    )  <- spring clip            | <- razor (edge on,
                       /  \                             |    sharp edge down)
        ____________---------___________________________|_______
       |          /_|       |__/|                       |       |
       |          | |_______|  ||  angle moulding       |       |
       |          | wood block ||                               |
       |----------|____________|/-------------------------------j
      /                           lay tube here and spin it    /
     /________________________________________________________/

    From: umn.edu!ux.acs.umn.edu!vx.acs.umn.edu!soc1070 (Tim Harincar)
      When I cut tubes, I always wrap the tube with about two
      layers of drafting tape with the edge of the tape along
      the cut line. This accomplishes two things: First the
      thick tape edge providing a excellent knife guide. Second,
      you can assure a straight cut. If the tape wrinkles when
      you wrap the tube, you know it is not on straight; simply
      remove the tape and try again until you know its down flat.

      Drafting tape is better than regular masking tape because it
      has almost the same thickness but is made to be removed.

      This method is in addition to reinforcing the inside with
      a stage coupler or spent motor. Also, always use a new
      x-acto blade for the best cut.

    From Jim Bandy (NAR member not on net):
      Use a piece of aluminum 'angle iron' for joining body tubes.  Place one
      tube in the angle, insert and glue the joiner, then insert and glue the
      other tube.  It give very straight joins.  The angle can also be used
      for marking fin lines on body tubes, etc.

    High Power Motor Hooks
    ----------------------

      billn@hpcvaac.cv.hp.com (bill nelson)
      I make a clip similar to the ones used on model rockets - however, I do 
      not pierce the motor mount tube - I place the front end of the retainer 
      over the front of the tube. It is epoxied/taped in place, just like with 
      a model rocket.  I do not rely on spring pressure to hold the clip over 
      the end of the engine. I use several turns of strapping tape - wrapped 
      around the engine or motor mount and the retainer clip. So far, I have 
      never had a problem with an ejected engine.

      From: Jim Cook <J.Cook@ENS.Prime.COM>
      Some folks at NARAM 33 suggested drilling a small hole in the side of 
      the flange of the rear nozzle retaining ring [of an ISP reloadable motor
      casing] to tie the casing to the model.  Some might claim this to be 
      "modification of rocket motors not approved by the mfg."  I had though I 
      heard Aerotech was going to start doing this themselves, but I haven't 
      seen anything yet.

      From: neil@boi.hp.com (Neil Pyke)
      I've built #8-32 "t-nuts" into my last couple of rockets and then made 
      sheet metal brackets to hold the motor in.  I drill two holes, 180 
      degrees apart, in the aft centering ring and then press and glue the 
      t-nut into the hole.  The screw holds the bracket to the centering ring 
      and I bend the bracket so it hooks over the end of the motor.  The t-nut
      works great but I've made my brackets too wimpy.  Those that saw
      me wandering  around just past the flight line at LDRS a couple weeks
      ago, looking for my ejected motor, will know that I have not perfected 
      my application of this design.

      From: Roger.Wilfong@umich.edu (A. Roger Wilfong)
      I've used a similar technique with t-nuts and had no problems - yet.  
      I've also tried a coarse thread sheet metal type screw (I'm not sure 
      what they're really called - the threading is about twice as coarse as
      a regular sheet metal screw) screwed into the rear centering ring at
      three locations.  The centering ring needs to be plywood and you need to 
      carefully drill the correct sized pilot hole for the screw.  After 
      'tapping' the screw into the hole, I took it out and ran a small amount 
      of thin CA into the hole for reinforcement - let the CA set before you 
      put the screw back in the hole or you won't get it out again.  This has 
      worked on RMS-29 and while it is not as strong as the T-nuts, so far it 
      has been more reliable than masking tape.

      From: hrbob@cbnewsb.cb.att.com (robert.e.wiersbe)
      [Bob] Kaplow uses special metal hooks that he bolts to the bottom 
      centering ring.  The hooks look like this:

                |\
                | \
                |  \
                |   \
                |
                |
                |
                |
         _______|
        
      He epoxies the nut to the inside of the centering ring, and the bolts 
      need an allen wrench to tighten (you could use any kind). He also has 
      different length hooks for different size motors. I think the hooks are 
      made out of brass.

    Parachutes
    ----------

    From: soc1070@vx.acs.umn.edu (Tim Harincar)
      Making your oun parachutes is pretty easy. Start with the desired 
      material (usually mylar or a light plastic). Make a cutting pattern out 
      of cardboard by first drawing a circle that will be the maximum size 
      of the chute (i.e. 16"). Take a compass [or] something that will give 
      you an accurate radius of the circle. Pick a point anywhere on the 
      circle and using the radius as a length draw an arc that crosses the 
      circle. At the point where the arc crosses, reposition the compass on 
      that point and draw another arc.  Keep doing that all the way around 
      the circle - you will end up with six points including the starting 
      point on the circle. Connect these points with a straight edge and 
      Presto! a hexigon. Cut out the hex from the cardboard (I use artists 
      matboard...) and this is your cutting template. Lay the template on 
      the material and using an EXTREAMLY SHARP XACTO KNIFE cut along the 
      outside of the template.  Make shrouds from a heavy guage thread - 
      cut three equal lengths twice as long as the diameter of the chute and 
      connect the ends to corner points adjacent to each other.
 
    From: Roger.Wilfong@umich.edu
      I usually build 12-24 line round chutes out of Estes material (just cut 
      around the outside of the red and white circle and attach at the red
      /white boundaries) because they look more like real parachutes.  I use 
      embroidery floss for shroud lines and separate the 6 strands (for 12 
      lines - use two lengths for a 24 line).  This makes a strong chute.  
      With out crossing the lines over the top of the canopy, I've only had 
      one failure of a 12 line chute (an EL that tipped off dramatically - 
      i.e. cruise missle) and never had a 24 line fail.  In the 10 years 
      I've been back in the hobby and using this technique, my shroud lines 
      have always come out the same length (within a couple of percent 
      tollerence).

    From: hal@HQ.Ileaf.COM (Hal Wadleigh)
      1. Use fisherman's snap swivels for your attachments.  It lets you 
         store 'chutes separate from rockets and helps prevent fouling due 
         to spin at deployment.[Note...modelers have always reported mixed
         results with snap swivels; they have been known to fail...Buzz]
      2. Use nylon coat thread for shroud lines on homemade 'chutes (and 
         plastic bread wrappers are the best cheap 'chute material).
      3. Pay special attention to the security of the attachment points.  
         Those standard stickers often look secure, but are actually not 
         attached.  A small knot in the part of the shroud line under the 
         sticker serves as a good anchor point (with the rest of that part 
         looped around the knot, as per standard practice).
      4. Very small 'chutes should be crossform type.  Cut about a 5" square,
         then take out about 1.25" squares from each corner.  Attach 4 lobes 
         of shroud across the flat ends and secure as above.  Be careful to 
         use small stickers for the corner attachments.  These make good 
         substitutes for streamers in .5" body tubes and can also be used as 
         drogues to help in the deployment of large 'chutes [A note from
         cdt@sw.stratus.com (C. D. Tavares): Either round off the inside 
         corner of that 1.25" square or reinforce the angle with something.  
         Otherwise, it's a really handy place for the parachute to rip  
         during a fast deployment.]

    From: smith@mrcnext.cso.uiuc.edu (Greg Smith)
      Nylon coat thread is very good for small, lightweight competition 
      parachutes, but it's not real strong and does have a tendency to melt if
      it encounters a bit too much ejection charge heat.  For sport and 
      payload models with 12" - 24" plastic 'chutes, I use 15 lb. *braided* 
      nylon fishing line.  It's thicker than the coat thread, similar in 
      diameter to the Estes cotton stuff, but tremendously stronger.  In the 
      last fifteen years, of the plastic parachutes I have built using this 
      line (and always crossed over the top of the 'chute for reinforcement), 
      I have had *zero* shroud line or attachment failures.  The braided line 
      has a hard, smooth surface that doesn't encourage tangling, and it 
      doesn't unravel where cut.

    Other Tips
    ----------

    From: whitman@nssdca.gsfc.nasa.gov (Rusty Whitman)
      I've tried about everything to keep shroud lines from pulling off of
      plastic or mylar parachutes.  Those little tape disks are just about
      worthless.  Tying knots and cyano'ing the ends helps but you still
      have problems.  I don't know why I never thought of this before but I
      ran across a roll of duct tape in my closet and knew immediately that
      that was the answer.  I cut out some little squares of duct tape and
      attached some lines to a parachute and they won't pull free without
      ripping the plastic.  I don't know who invented duct tape but they
      deserve some kind of statue, its got more uses than a paper clip.

    From: utidjian@remarque.berkeley.edu (David M.V. Utidjian):
      A better way to glue parts together than water based glues (such as
      Elmer's white glue) is to use 5 minute epoxy. You have to be fast and 
      organized, if you are too late just swizzle up another batch.

    Source unknown [but sounds like good advice to me...Buzz]:
      Make a jig for anything you do more than once (align fins, 
      join body tubes, etc.).

    From: ixhwd1!hrbob@ixstar.att.com (Robert E. Wiersbe):
      I have found (through unfortunate experience) that all 5 minute epoxies 
      are not equal, I now use 30 minute epoxy in all my construction. When
      attaching fins I put epoxy on the root but leave about 3/8" open at 
      each end, then put CA on the exposed area an align the fin. The CA will
      hold the fin in place while the epoxy cures. 


----------------------------------------

Section 11: Ignition and Launch System Tips

11.1 How do those 'Copperhead' igniters work?  They only have one wire?

    Copperhead igniters are actually two strips of copper wire with a
    thin mylar insulating layer between them.  To use these with regular
    alligator clips you need to use masking tape to insulate opposite sides
    of the igniter from each clip.

           'Thin' (side) view of copperhead igniter:
                       |    |
                       |____| < Motor with Copperhead inserted
             Masking   > ||
             tape      > ||
                         ||
                         ||<  Masking
                         ||<  tape

    Attach one alligator clip at each masking tape point, so that each clip
    only makes contact with one (opposite) side of the igniter.

    The Quest 'Tiger Tail' igniters are the same type of ignitors as 
    Copperheads.  They come with a special 'wrapper' with openings for 
    alligator clips.

11.2 Do you have any specific suggestions or tips for an ignition power
    sources? Can I use my old Estes ignition system with composite models?

    The Estes, Quest and other model rocket launch systems are fine for most
    model rockets.  If you do a lot of flying there have been some suggestions
    posted to the net.  If you are trying to launch cluster models with solar
    igniters you will need more 'juice' than 4 AA batteries can provide.  This
    is also true of clustered Copperhead type igniters.

    From: cdt@sw.stratus.com (C. D. Tavares)
      A motorcycle gel cell, however, will last a long, long time.  
      Our club uses a gel-cell the size of three VHS tapes to launch 120 
      rockets over six hours, and it comes home at about 80% charge.

    From: billn@hpcvaac.cv.hp.com (Bill Nelson)
      I bought a 12 volt motorcycle battery for about $20. I only need to 
      recharge it 3 or 4 times a year. I have adapted all my launch 
      controllers to allow usage of the battery.

11.3 WARNING:  BE VERY CAREFUL USING ANY IGNITION SYSTEM WITH 'FLASHBULB' TYPE
               IGNITERS.

    Many (most?) launch ignition systems are not 'flashbulb safe'.  Just 
    arming the circuit (i.e., doing a continuity check) will fire the 
    flashbulbs and ignite the motor.  If you plan to use flashbulb ignition 
    often, you might consider investing in a 'flashbulb safe' ignition system.

    From J.COOK@ens.prime.com (Jim Cook):
      A lot of launch systems use a light bulb to do a continuity check.  
      The current through the light bulb is enough to set off flash bulbs
      (They require only milliamps to fire).

11.4 THE IGNITION OF ROCKETS BY OTHER THAN ELECTRICAL MEANS IS BANNED BY BOTH
     THE NAR AND TRIPOLI SAFETY CODES AND SHOULD NOT BE USED.

    There was a fairly lengthy discussion in r.m.r about the use of hand-lit
    fuse to launch rockets.  Although there was an advocate of this method the
    consensus opinion of the net was that the NAR and Tripoli safety codes 
    made good sense, hand-lit fuse igniters were unsafe, and electrical 
    ignition (even if igniting fuse by electrical means) should be used for 
    all activities.  Hand-lit fuses are also against most state laws.

11.5 How do you ignite second stage composite motors?  Can I use a black
     powder booster for the first stage to ignite the second (as I do
     with multi-state A-D rockets)?

    Upper stages of composite powered models may be ignited by 
    electrical means or thermalite fuse.  North Coast Rocketry has 
    a Technical Report covering this subject.  Excellent articles have 
    also appeared in AmSpac and the Tripolitan.

    You cannot use a black powder booster to ignite a composite upper
    stage.

11.6 Other ignition tips:

    From: dwade@jarthur.claremont.edu (Doug Wade)
      [concerning adapting launch controllers to 12V car batteries ...]
      Speaking of which, I took my Aerotech launch setup, lopped off the
      ignitor attachment, and the place where it attaches to the battery, put 
      amp plugs on either end, put a plug on the battery, and made some 
      alligator clips in various configurations for launching Estes stuff.
      This means that I can switch batteries and ignitor style in basically 
      no time at all.  It's not a lot of work, and it makes life easier.  If 
      you have the urge to do this kind of thing, make sure that you get 
      plugs that can handle it.  A 12V motorcycle battery (Mine was about 
      $40 but it's pretty nice) can put out something like 15A for a short 
      period of time...


----------------------------------------

Section 12: R/C Rocket Glider Construction Tips

The D-G powered R/C rocket gliders now available are presenting some new
problems to ModRoc'ers, who are more used to making balsa wings, fins, etc.,
then built-up wings.  Here is a set of tips submitted by Iskandar Taib, a long
time model plane enthusiast, and others.  There is an excellent FAQ in the 
rec.models,rc news group.  It includes very good information on how to get 
started into R/C flying, tips on where to buy equipment, etc.

12.1 Construction Reviews

     Aerotech Phoenix:     August, 1992, "Model Builder Magazine"
     Estes Atroblaster:    September, 1992, "Model Builder Magazine"

     Both articles are written from the perspective of experienced R/C
     aircraft modelers.  They both contain good construction and flying
     tips.

12.2 I'm building the 'XXX' R/C Rocket Glider and it uses foam core wings. 
     Are there any  things I should know about working with foam?

     The first thing to know is that certain paints and glues dissolve
     foam. Both the stuff made out of white beads (referred to as "bead-
     board") and the blue (Dow Styrofoam (tm) ) or pink (DuPont Foamular)
     extruded foam will behave in the same way. Once sheeted a foam wing 
     can sometimes be finished in a paint that ordinarily dissolves foam 
     if one is careful about not putting too much on at a time. Here is 
     a list of what will dissolve styrofoam and what won't:

     Will dissolve foam:

        Nitrate and butyrate dope
        Ambroid
        "Model Airplane Cement" (you know what I mean)
        Polyester resin (sold as "fiberglass resin" at K-Mart)
        Thick and thin cyanoacrylates (excepting UFO)
        Paints from spraycans
        Dope and paint thinners
        Gasoline
        Dope thinner, acetone
        Solvent-based contact cements

     Won't dissolve foam:

        Polyurethane paints and varnishes (inc. Rustoleum)
        White or aliphatic glues (Elmer's, Titebond)
        Epoxies
        Ethanol or methanol (sometimes used to thin epoxies)
        UFO superglues
        Water-based contact cements (eg. Southern Sorghum)

     Follow the instructions provided and you won't go wrong. Most struc-
     tural building is done with white glue and epoxy is used for sheeting
     the wing and/or putting down fiberglass, graphite or kevlar cloth.

12.3 Any tips for sheeting the wings on my Aerotech Phoenix?

     The Phoenix kit requires that you sheet the wing with balsa using epoxy
     as the glue. Aerotech also recommends that you vacuum-bag the wing for 
     the lightest wings possible. Vacuum bagging is a fairly new technique 
     that I will describe later. 

     The process involves preparing the wing skins, mixing the epoxy (need-
     less to say, the 24 hour laminating variety, spreading it on the skins 
     with a squeegee, scraping most of it off, applying the skins to the 
     core, then assembling everything together in the core beds (the pieces 
     left over after the core is cut), and putting lots of weight on top 
     of the whole thing. Oh yeah.. the wing has to be kept straight so 
     you'd have to do this on a very flat surface. The more pressure you 
     can put on this, the better glue joint you'll have, and the less glue 
     you'll have to use, which makes for a lighter wing. 

     VACUUM BAGGING

     This is where the vacuum bagging comes in. The core bed/sheeting/core
     assembly is put into a large bag which is sealed on all sides. Then the 
     air is pumped out of the bag. This is supposedly the equivalent of pi-
     ling hundreds of pounds of weights on the core. In fact they tell you 
     to limit the vacuum to so many inches Hg otherwise the cores will crush.

     Vacuum bagging is also useful if you are going to lay up fiberglass 
     on top of the balsa wing skins. Fiberglass cloth is now available in 
     very light weights and people often use it in lieu of a covering film
     or fabric. 

     The way it used to be done was that the cloth was laid down and a thin-
     ned (with alcohol) epoxy brushed into it. Then excess epoxy was removed
     using rolls of toilet paper (discarding layers as they became saturated). 
     
     With vacuum bagging one lays down a sheet of drafting mylar on top of 
     the wet glass cloth, then puts the assembly in core beds. The assembly 
     is then vacuum-bagged. After curing the mylar sheets are removed and 
     you end up with a glass-like finish that is extremely light since all 
     excess epoxy has been squeezed out. This also obviates the need for 
     lots of the filling and sanding usually necessary before painting.

12.4 How about help with my Estes Astroblaster wings?

     The Astro Blaster kit uses contact cement for sheeting the wings. The 
     cement is of the water based variety. Itis applied to both skin and core 
     and is allowed to dry. After this has occurred, the skins and core can 
     then be brought together. This is a little trickier, since you don't get 
     a second chance.. Once the core touches the skin you can't separate them 
     without breaking something. The skins are just 1/32" thick so one 
     has to be gentle with them. 

12.5 How do you repair damaged foam wings?

     Repairing foam is fairly easy. One simply hacks out the damaged piece, 
     glues in a block of foam and carves and sands to shape. Carving is best 
     done with a brand new utility knife (the kind that has break-off points)
     and sanding can be done with a sanding block. Sheeting is replaced in 
     the same manner - cut out the damaged piece and glue on a replacement. 
     A little glass cloth or carbon fiber matte over the break helps too. 

12.6 Some more uses of foam in rocketry...

     Foam is interesting stuff to play with. You can cut wing cores using a
     hot wire and 1/16" ply or formica templates. Parts for rockets can be 
     made by simple carving and sanding. 

     Even more interesting is making lightweight wings and other parts using
     foam, silkspan and thinned white glue. Someone called Ron St. Jean built
     lots of competition free flight models in this manner. The silkspan is 
     applied wet over the foam, and thinned white glue is brushed on. When 
     the silkspan dries it shrinks, and the result is an incredibly strong and
     stiff structures. One could conceivably use this method for nose cones
     or complex scale models. In England, foam and brown wrapping paper is 
     used for complex ducted fan models (someone actually flies a seven foot 
     long scale Concorde constructed like this). 

     If one uses heavier paper (eg. grocery sacks) perhaps one can dissolve 
     the foam once the white glue is set (use acetone or dope thinner for 
     this).  For rockets imagine something shaped like a V2 made like this. 
     Once the foam was dissolved you'd end up with a light weight craft paper
     tube of the proper shape, boat tail and all.

12.7 I need to cut the piano wire control rods.  Bolt cutters don't work well,
     as the metal is too hard.  Any ideas?

     From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
     What you want to do is get your hands on a reinforced cutting wheel
     like the House of Balsa Tuf-Grind. The Dremel ones tend to shatter and 
     throw pieces at high speed. If you use them harden them with thin 
     superglue.

*===========================================================================*
*                  END OF REC.MODELS.ROCKETS FAQ                            *
*===========================================================================*
From: galenr@hpgrla.gr.hp.com (Galen Raben)
Date: Fri, 2 Oct 1992 16:17:27 GMT
Subject: Re: what are payloads for?
Organization: Hewlett-Packard, Greeley, CO