Provisional SPORT JET SPEED Rules

All A.M.A. rules from the control line general and control line speed sections shall be applicable, except as follows:

1)  AIRFRAME & CONTROL SYSTEM:
   1.1  Any design configuration and construction method is permissible so long as the contest management considers the model to be safe and sound.
   1.2   The engine and engine mounts shall receive a 40-pound pull test.
   1.3  The control system must be mounted external to the normal aircraft contours.  This includes the bellcrank, leadouts or control lines, pushrod, and elevator horn.  The leadout guides can enclose no more than one inch of the leadouts or control lines.
   1.4  The maximum weight of the aircraft in ready-to-fly condition including fuel shall be 45 ounces.

2)  LINES & PULL TEST:
   2.1  The model must be flown on two single strand steel control lines of .022 minimum diameter.  The distance between the centerline of the fuselage and the center of the control handle grip shall be a minimum of 60 feet.
   2.2  The control lines must be connected using either 1” long scissor type connectors (pylon #149) or equivalent or mono line type buttons mounted to the bellcrank.  The latter method must be used in conjunction with line leadout guides in order to prevent the lines from rolling off the buttons in the event of a crash.  The minimum inside diameter of the buttons must be .125”.
   2.3  The model and entire control system, lines and handle shall receive a forty two (42) g pull test.

3)  ENGINE:
   3.1  The allowed jet engines are the Dyna-Jet, Bailey Sport Jet, and the O.S. II.
   3.2  It is required that the engine shall be in stock condition internally.  No material may be removed or added to the engine, except as follows:
      a. Engine head:   The last three fins on the head may be machined to a diameter of .020 less than the fin in front in order to receive a mounting strap or ring.  Holes may be drilled into the head for purposes of engine mounting. .  The fins on the head of the engine must be exposed. Engine cowling is not permitted. Streamlined fairings ahead of the engine cannot be attached to the head. Valve face may be lapped as needed for routine maintenance. 
         1.   All or part of the fins may be removed from the head, but the Red Anodizing MUST be present in the intake throat and the 10 air passages. The Valve face may be lapped as needed for routine maintenance.  No cowling is allowed.
      b.  Flowjector:  Fuel feed holes may be drilled out to larger size, or filled and redrilled. (holes allowed in original location only).  If a tire pump is used to start the engine then a short piece of metal tubing may be installed into the tire pump connection to facilitate quick removal of the air supply hose.  Alternatively, the threads on the tire pump connection may be filed off, or filled in so as to make a smooth surface to facilitate quick removal of the air supply hose.
      c.  Metering jet:  Any metering jet may be used, and may be located anywhere between the tank and the flowjector.
      d.  Tailpipe:  A stock tailpipe with ignition plug in place must be used. (starting ignition may be by means of a starting probe).  Repaired tailpipes are permissible, provided stock dimensions have been faithfully adhered to.  The front surface of the tailpipe (combustion chamber screw ring) and the lock ring may be lapped.
      e.  Reed valve:  Any commercially available valve may be used.
   3.3  Interchanging of parts between the above listed engines is permissible. (i.e. use a Dyna-Jet head with a Bailey pipe).
   3.4  Fuel delivery to the engine shall be by suction, no pressure feed is allowed.

4)  FUEL:
   4.1   Fuel will be supplied by the contest management
4.2  Fuel used shall be the A.M.A. formula:  80% methanol & 20% propylene oxide.

5)  OTHER:
   5.1  Scoring of the flight shall be a time of  ½ mile  (7 laps). Timing will start after the pilot has completed three laps in the pylon.
   5.2  All other general rules for control line speed flying (attempts, number of models, competition flying from pylon, timing of flights, etc.) shall be applicable.
   5.3  Entrant of the model shall, in each attempt for flight, participate as the pilot or an active member of the starting crew. The only acceptable exception to this rule would be if the entrant were handicapped and unable to perform pilot or starting crew duties.

old rules. notice the fuel is not current also. it is better than nothing.

Have the posted rules been updated and correct?

  updated rules for sport jet.

Joey,

Thanks for bringing up the topic of moving the Sport Jet event under AMA control.  This is an event which is slowly growing in popularity and would benefit from having stable rules which would not be subject to change by a small group to outlaw the airplanes of a faster competitor (Didn't work, did it?).

Here are my suggestions for AMA rules which could further advance Sport Jet.

Control System:  Adopt the present AMA rules for 1/2A profile proto from page CLS-7, Section 19.2, Paragraph i.  This adequately covers the original intent of SJ, and is already in the rule book.

The next two suggestions may be controversial but deal with the relativly small number of actual flyers in our aging community, who must rely heavily on proxy pilots to fly their airplanes for them.  I have suggested that line length be increased from the present 60 feet to 70 feet, reducing pilot turn rate and line pull substantially.  Line diameter could be safely reduced to 0.020" with corresponding reduction in pull test.  We expect 10 Sport Jet entrants at Whitter this weekend,  most of whom will need proxy pilots on the present short lines.  I'll float the longer line suggestion to them.   Last time I suggested this to NASS the response was basically:  "I don't like it"  Lets have a better reason to discourage growth  of this class.

The second suggestion is to allow engine modifications not visible externally (Opening of ports can easily be seen looking into the intake).  Whenever I've had a fast flight, I've pulled the head, to show stock reed and retainer, at the end of the day.  Unless internal mods are permitted, the rules should require demonstration that the engine is internally stock.  Allowing non-stock reed retainers might gain back somof the small speed penalyt resulting from longer lines.

See you this weekend,   Will

Joey,  They'er sitting in my tool box right now.  I've flown with them several times, and skidded off twice.

Best,  Will

ill fly my sport jet on 70 to take the pressure off George Brown and Joey.....

From our perspective over here we have no flying sites that can cope with the 70ft lines. We encourage as many people to fly as possible. THe rotation speed on 60ft lines is still rather slow so see no need no need to change it..  Even Don Robinson at 76 yrs young is still flying his beast well. Its all about practice practice. IT seems a lot of fliers just fly at compititions. This is nice but not practical. Maybe some practice events need to be held where no official times are taken. Team race pilots seem to cope well so twist some arms...   If a line length is to be increased go for 65ft or 19.9m but even with these its not the rotation its the pull which people struggle with

Just my thoughts
Robert Bolton

Hi Robert,

What line length is used for fast jet?

Best,  Will Stewart

Robert i have seen the KIWI'S use a cross bar in sport jet i belive it was Brendon. I like the idea of using the cross bar to take the pull.

i do know this event is a lot of fun for a lot of flyers. and we should not mess with one of the most popular events. maybe we can try an event using 70' line and sport jet rules and call it classic jet. this is some we need to play around with to make sure it works, if we do this at the next whitter contest i will let you know how it goes.