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Shut-off for F2D-Combat
World Championship, France 2008

Last update: 15/10 2008
I think many pilots went to the World Championship in France this summer hoping to see some demonstrations of shut-off systems. Maybe even ready to buy a couple of systems to test this fall.
There were a lot pilots and plenty of dealers - but no shut-offs!

The biggest shut-off news in France:     NO NEWS

Well, after all, there were a few things to write home about:

Chuck Rudner swing-arm shut-off

Chuck Rudner showed a simple swing-arm shut-off.

Chuck Rudner:
I have a small lightweight centrifugal shutoff that is entirely mechanical without electronics which could be easily reproduced, similar to what was at one time available via the Mejzlik catalog. As I did with Tomas Mejzlik, I would be happy to allow mass production of this device for anyone to purchase from the manufacturer and use until perhaps the electronic devices are debugged, if someone wants to mass produce them. I do not ask for any fee or royalty but only that I can purchase them once available. Any takers? I showed this device to the Wakkermanns and Henning Forbeck in France at 2008 W/C.

SwingArm Shut-Off by Chuck Rudner
SwingArm Shut-Off by Chuck Rudner
SwingArm Shut-Off by Chuck Rudner

These two links are to videos of my shut off.

The first shows that after start up, engine vibration does not cause it to false fire while running in the pits prior to launch and that it does not false fire throughout an entire match. After running out of gas and plane has landed in the grass, I demonstrated that it successfully armed on launch in the shut off position after it landed. Since our field is next to a busy freeway, I cannot let go of the handle to demonstrate actual shut down of flight on this video, but I have used these types of shut offs for many years in the past for F2D practice matches with successful shut downs when needed.

The second shows that a mechanic can run around the circle with a running engine without causing the shut off to false fire. Also, the streamer ring can be attached without causing the shut off to false fire. The last thing I did was trip the shut off to show that it shut the engine off.

/Chuck Rudner

Update 15/10:
If necessary, my shutoff could be tripped by the mechanic just before launch and held to the outboard side until the model is released. The centrifugal force builds up fast enough on takeoff that the time the engine runs on the fuel in the line between the shutoff and the spraybar allows it to function on takeoff without the armong function working.

This feature has been used when arming spring gets cut off in a collision but without the arming spring, two mechanics are required to start the model.
This would still meet the general rule for the device being active for the whole flight.

/Chuck Rudner


Electronic shut-off in France

A France Team Race pilot (as far as I know) demonstrated and explained an electronic cercuit for a shut-off system. I didnīt see the system in France but Mike Willcox got it on video. You can see it here:

Forbech 2007 Shut-Off

Old news in France: My shut-off system from last year.

I brought a couple of old models with my 2007 shut-off to the World Champs i France.
A lot of people got a chance to examine this shut-off in real life.

In the break between two rounds Boris Faizow got a chance to try one of my shut-off models in the air.

Venturi and muffler rules

A couple of weeks before the World Champs in France the Chairman of the C/L Subcommittee and the F2D Judges Group sent out a document with Technical Rule Clarifications for F2D. This document had a new and radical interpretation of the rules on checking the size of the venturi and mufflers.

This document resulted in some debate on the internet and at the start of the competition in France. Some pilots even had to make drastic changes to their engines right before the competition to fullfill the rules.
I found this conflict in the interpretations of the rules very strange. None of the pilots has any interest in changing from the normal "low tech" inspection to a more restrictive "high tech" inspection. Only the organizers insisted that all engines should comply with their new and extreme interpretations of the rules.

I think that all pilots at the World Champs in France learned that it is not enough to think you know the rules and just do as we used to. After all the trouble in France we have learned that we must be prepared for even the most extreme interpretation of the rules.

This was a good reason for taking a closer look on the 2009 shut-off rules.

See what I found in the new shut-off rules


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