I would say no, but it would be interesting to read about the pros and cons. Any links?

cheers,
Ken

Wow, Joey 

I hope nobody thinks I put you up to this.  There shouldn't be any restrictions on airplane design beyond those in the NASS/NW Sport-Jet rules.

The problem with SJ is the NASS short lines (and the NW thin lines).  Every effort should be made to consolidate the S-J rules of both organizations with each giving a little.

A problem which has not been really examined, in both Sport and Fast jet, is the speed of the dolly when the airplane lifts off., which is much faster than with prop jobs  It was mentioned on the Speed Forum that, if anyone gets hit, dollys will probably have to be tethered
of banned by AMA.  For this reason, since sidewinders seem to require dollys, there might be problems on the horizon for this design. and we all would have to skid off.

If this happens, the LIGHTER the line the better skid-off performance, regardless of line length (do the Math).  The only way to slow dollys down is with large wing area for the airplanes, which is a whole nother problem.

Joey, you should be in favor of longer S-J lines to reduce your contest work load.

Dynasoar 1948

In response to Patrick's questions I'd like to add my 2 cents worth.  I don't think there should be any restrictions on SJ design just like there is none in Fast Jet 309.  There is nothing in those reles that say you have to run a Sidewinder.  A properly set up sidewinder is probably faster but the rules don't require you to run one and I feel no design restrictions were originally intended in SJ nor should any be added.  There are probably more uprights flown now than Sidewinders and one of the 3, Will Stewarts, 150 mph sport jets is an upright.

I'm fine with the 60' .022 line size we have now although I'd still fly if we went to 70' say .020 but that would not be my preference as I feel the pull and rotation at 150 mph is not a problem with my 67 1/2 year old legs.  Rotation speed in F2A however is.

The stock engine rules per NASS are good with me although the NW rules allowing fin removal and possibly cowl behind the mouth would be alright with me.  I could go along with no spark plug as both DJ and Bailey both made pipes without plug holes.  I had to put one in on mine to conform.  Require the original anodizing in the intake throat and ports to be present.

Jim Rhoades  

Robert,
Thanks for your excellent post.  I've been preparing a proposal for NASS to permit official flight with either 60 ft X 0.022 or 70 X 0.020 lines. on a provisional basis.  Currently covering the safety issues of the longer lines.  The longer lines will theoretically cost between 2 and 3 MPH, but, as appears to be the case with experimental flights on the new 65 foot A lines, no noticable loss has  been observed.  Possibly a case of the pilot not holding the airplane back as much.

I hope that ultimately NASS and North West Sport-Jet rules can be unified.  Ultimately NZ?

Will Stewart

New SPORT JET MODEL

 Hello Robert,
If I remember correctly from talking to Andrew at the Nats you folks don’t use propylene oxide in your fuel for the jets do you?
Are you folks using nitro instead?
Any other type of igniter (ingredients) yawl use?
I remember when the fuel was unlimited in the jet event here in the U.S. in the past. (Is this how yawl play this sport there)?

Thanks,
Patrick

 ;Dwellllllllllllllllll  joey mathison.....jim welch in virginia to say hi...just got the puter up again...whats up?

Sure remember joey was an amazing thing to see a d plane move your big carcas flatfooted 10 feet outa the center and watch you bulldog it back even though our 203 wasn't allowed because louisiana asplalt is soft in 110 degree weather he he he.flew today at fentress with your dad willis and john tate.one airplane a month ago turned into 6 today.Cleaned out the hanger and got a lot of room. Seems strange without 20 combat planes d speed 21 speed rats formula 40's  etc. but have much room for jello as they say.I'll be yapping with you soon   jim

Robert,

Good to see you here on this forum.  I'm packing now to go to Whittier Narrows for the toys for Tots meet to fly Sport Jet and F2A.  It will be the last meet of the year and the weather report says mid to upper 70's f.  That's 24 to 26 c for you guys.  That's nice pleasant weather especially compared to the high today in the mid 20's that's about -4c and too cold for me.

If the weather and temp's co-operate and I'm home I hope to start off the new year with a bang also.  Unfortunately new years eve here usually means temps well below freezing but if we have an unseasonably warm evening I just might lite off the Sport Jet to wake up the neighbors.  If it's cold I'll probably be asleep myself.

Say hi to the NZ gang for me.

Jim Rhoades

Except for practice, Sport Jet seems to be the perfect event for both experienced as well as new-to-speedsters.

I hesitate to say it is a good beginner event because I am certain that there is no good speed event for a rank beginner. Speed flying is not nearly as technical as stunt, carrier, racing and can't be more demanding than scale, but ANY speed engine setup can be a PITA. Running a recip on the ragged edge of RPM demands attention to many variables in terms of prop, compression and fuel delivery. Mr Tenny in his infinite wisdom provided us with an almost perfect propulsion system [I for one can live w the heat and actually like the sound]

Use common sense to keep it simple [read easier, but not easy]!!!

Even with no prop or plug, there are still enough variables in skill and design to keep it interesting. DO NOT LIMIT DESIGN!!! Let us Rube Goldberg types enjoy something.

The event existed in several places and seemed to be very popular in the Northwest, using some form of rules that must have worked for everyone involved. This proves both the worth of the event and the necessity for SOME rules.

I always mention Mouse Racing when I get on one of these JAGS. Don't allow SJ to become MR!!!

.21 SS, like almost all other events, has advanced to the point where the top 5 competitors can EXCHANGE airplanes and the results will be the same. This is a good thing, because this is REAL racing. A body of knowledge exists, and if a person is patient and attentive, this knowledge will become apparent.

SJ, with varibles limited to "stock" engines or readily available BOLT IN replacement parts, leaves only airframe, building and flying skill as the focus. I am sure that there is "a perfect" design out there for SJ, but so far, none has become apparent.

Funny, a stock DJ is probably the simplest speed engine to maintain. [just a little touchy getting helpers]


BTW
The thing I like about this FORUM is that it may attract some guys that fly other disciplines, just as it seems BIG JOEY has turned to stunting!!!

I usta think stunt was low tech, then I went to Bob Hunt's place...building those things, at least the top of the line stunters, takes some serious effort and quite a bit o jack [$$$] Also, time to build, like sometimes a year??? And they get into these very serious discussions about engines...

Also, the real guys fly this pattern thing and they seem to be able to tell the difference between one pilot and another [I can't tell any difference]

nah
I don't have the time or the interest
just like going fast