SEN 1933

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Table of Contents – SEN 1933

  1. Airtek
  2. 1993 AMA Nats
  3. What’s Hot 1
  4. Elephant in the corner
  5. F1ABC-2 Sweden
  6. Del Adam

New Airtek Web Site
By coincidence my old Airtek web page died at the same time I was moving to a new house in northern California and a few people were worried that my electronics were no longer available. I’ve finally put together a new webpage for my free flight electronic stuff here: My new address and contact information is available here. I’ve consolidated things as I no longer build or support the altimeter or DT timer. Items available are the RDT systems, radio beacon, and LED flasher.
Thanks, Ken Bauer

1993 AMA Nats
I am undertaking a research project and have been unable to locate the 1993 Nats results. Can anyone help?

Don DeLoach

What’s Hot 1 – E-36 and F1S


Last year a submission was made to the CIAM to create a mini electric class called F1S based on the popular USA E-36 class. This was close to the E-36 spec with a few differences, probably typographic. The proposal was withdrawn before the meeting with no reason given.

A proposal has been submitted again by a different source. This was the E-36 spec except that it permitted an auto rudder. There has been significant discussion around this on FB and the consensus appears to be that the model spec should be in line with the E-36 airframe rules. A survey is being done by Don Deloach on this subject.

The E-36 is a very successful small field class and a number of Europeans were disappointed that the F1S proposal was withdrawn. In line with other FAI outdoor classes the F1S has different flying rules with rounds and increasing flyoff times. It still uses the E-36 decreased motor run for the flyoff. There have been a number of successful mini-event series outside of the USA and having a FAI F1S class would simplify adding an electric event to those classes.

It has been suggested by those “in the know”, which clearly I’m not that the reason why the original F1S class was withdrawn was because the submitter felt that the FAI community had messed up F1Q and they did not want this to happen to E-36. This reasoning is flawed because E-36 is an AMA/NFFS class and the FAI cannot change the rules of that class. If the F1S deviated from the E-36 is some “undesirable” fashion, for example by requiring energy limiters then people would probably just not fly it.

If the F1S class was introduce than SCAT would probably add it to the America’s Cup mini-event line up. Giving the E-36 guys another event to fly in.

F1Q, E-36 and the Elephant in the corner


There has been much discussion and comparison between F1Q and E-36. Here are some of the key points.

The F1Q rules were changed from the original specifications to include energy limiters. A change was required because the performance was too good but ignoring for the moment the choice of energy limiter the specs have been changes several times since. It does not appear that the changes to the rules were clearly thought out or tested before each change. In addition the objective of the class was not well defined or rather subject to some confusion, some regard it as an open class where the contestant chooses big model slow climb or small model fast climb. Others think it should be an electric F1B class with a slow climb while others think it should be a quiet F1C with a fast climb. All of this has contributed to confusion and lack of participation for both event organizers and potential sportsmen.

The E-36 was designed to replace another class that had been rendered obsolete by new motor and battery technology. People were assigned to build and fly model to the proposed specification. The performance was limited by the span of the model and restriction on moveable flight surface. Once introduced the rules were not changed. A number of kits and plans have been produced and article written about the event. In spite availability of the batteries and motors changing the class has been very successful in introducing many people to electric flying.

The elephant in the corner is the risk that a contestant will employ a very expensive strategy to gain an advantage. Examples are using a very expensive motor and/or battery technology or flying a battery to destruction each flight. One of the appeals of electric flight is the comparative low cost of the motors and batteries on the general hobby market. The FAI has some experience with the cost escalation with the F5 R/C classes and that was the reason the energy limiter was chosen for F1Q. This approach is technically complex and a little difficult to administer. The approach chosen by E-36 was to limit the performance by the airframe rules. Here the putting a much more powerful motor/battery combination on the model with make it difficult to trim and fly reliably. Neither of these approaches is perfect. If the F1Q community had not kept fiddling with the rules people would have probably adapted better to the energy limiter. On the E-36 front it has proved very difficult to attain the 2 min max with a 5 second motor run without thermal assistance, people are trying and I have seen models that claim to be able to do that consistently. What will be interesting is to see how many people can achieve this and the trim used to do this is stable for normal flying.

It should be pointed out that with E-36 so far no one has come up with some expensive motor or battery or a destructive motor strategy so this fear may be a moot point for this class.

There is a FAI power class, F1P where the performance is limited by the airframe. This is used for the Junior World Champs. It was thought when this class was introduced that people would fly the classic spiral climb AMA style gas job. This was the case from a couple of years. Now the top flyers use a much less stable trim where they tweak it in the fly off to get more performance with greater risk. This has reduced participation in the event because not many kids nor their coaches can achieve this level of performance.

F1ABC-2 rules in Sweden for simplified competition FAI models.

Some free flight modelers have been worried that there is a niche or number of modelers that think that FAI high tech models are too costly and demanding so they stay away from taking part. By introducing parallel classes with limited technical functions this would attract more modelers to take part. Nobody has proven that this hypothesis might be true but there has been a lot of suggestions in several countries for different types of rules for several years to achieve this. Some propose integrated models with added line length to compensate for lower tech and others want new classes to be run in parallel. In Sweden we have tried this with limited success. This may be due to the low numbers of freeflight modelers in this country or to other reasons. The whole idea probably needs to be introduced internationally to catch on.
Anyhow we presently have rules for lower tech models to be run separately or in parallel with FAI models. We call them F1ABC-2.
Class F1A-2
Total Lifting Surface 32-34 square decimeter.
Min weight 410 gram.
Max tow line length 50 meter at 5kg load.
Any change in airfoil camber, wing angle or wingarea is not allowed. Only one function on timer is allowed one which ends flight (DT). A change in stab angle during tow in order to ease tow in weak wind conditions is allowed.

Class F1B-2
Total Lifting Surface area 17-19 square decimeters
Min weight 200 gram
Max rubber mass 30 gram.
Any change in airfoil camber, wing angle or wingarea is not allowed.
The prop is not allowed to have delayed start, variable pitch or diameter.
Change in stab angle or rudder is allowed once each during flight. Then finally DT.

Class F1C-2
Total Lifting Surface 25-38 Square decimeters.
Min vikt 300 gram x cylindervolume (ccm).
Max engine size 2,5 cubikcentimeters.
Max engine run time 7 seconds
Any change in airfoil camber, wing angle or wingarea is not allowed.
Change in stab angle or rudder is allowed once each during flight. Then finally DT.
Engines allowed should be available for everybody on the comercial market.
Fuelmixture according to F1C rules. Prop must be direct drive. Variable pitch and folding not allowed. The engine must have a muffler.

These rules are presented here in order to contribute to the international debate on the ever ongoing debate on freeflight survival or how to increase participation. There is nothing special in them and hopefully they will contribute to the ongoing debate.
Inge Sundstedt/Ronald Borg.

Del Adam
With sadness I report the passing of Del Adam, 76,
of heart failure in Visalia, CA
Del flew with the Sky Kings
of TulareCounty for many years and haunted the free flight contest fields of Taft, Fresno, and other sites with
his silk-covered Mexi-Boys, Lipsticks, favoring the designs of Al Vela. He will be missed by all who knew him, Del was a Marine. RIP
Craig Bartle

Roger Morrell