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Aug 21, 2016, 07:37 PM
Flying = Falling (Slowly)
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F3-RES Rules -- Translation/Interpretation


I have attached a cleaned up Translation/Interpretation of the German rules for F3-RES. Mostly, I have tried to clean up the prior translation that was posted in RC Groups. Some of it did not translate well and I did the best I could to interpret the intent of what was written.

In a few instances I provided additions or clarifications that were more in line with practices with which we are familiar.

It is not perfect. And I am sure that others who are familiar with the event can provide better clarifications.

Finally, I am offering this not as a recommendation or anything like that. Just food for thought -- and comment.

Happy Landings,

Don
Last edited by dharban; Aug 21, 2016 at 10:54 PM.
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Aug 21, 2016, 07:39 PM
Flying = Falling (Slowly)
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.........
Last edited by dharban; Aug 21, 2016 at 10:54 PM.
Aug 22, 2016, 09:39 AM
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Jim Deck's Avatar
Don,
Thanks for posting this translation - it will help. This class has got a lot going for it - it would be nice if it caught on. The availability of a competitive ARF might help.
Aug 22, 2016, 12:28 PM
supreme being of leisure
ZAGNUT's Avatar
the way i read it the "shapes" in "GRP/CFRP/Kevlar tube or shapes" means "stock shapes". IOW, no custom molded parts unless someone wants to roll their own tubes or laminate their own plate and cut parts from it. a tapered tube would be considered a stock shape but a tube with integrally molded mounting points would not.

"The wood parts of the fuselage may be reinforced on their surface with GRP/CFRP/Kevlar.".....pretty much allows balsa cored composite construction so probably isn't interpreted correctly. the way i read the rules it is allowed only on the outside surface of the fuselage and only as a finish, not as any type of structural reinforcement. would probably be wise to even drop the carbon and kevlar.
Aug 22, 2016, 12:50 PM
Sagitta Fanboy
Quote:
Originally Posted by Jim Deck View Post
Don,
Thanks for posting this translation - it will help. This class has got a lot going for it - it would be nice if it caught on. The availability of a competitive ARF might help.
I'd expect if there's any takeup we'll quickly see Hobbyking put out a viable ARF (they'll probably clone one of the german or turkish kits, as they did with the Dynamo Minitermico)

Sadly, today there doesn't seem to be any remaining 2m woodie ARF's readily available, let alone something competitive.
Aug 22, 2016, 02:08 PM
Registered User
You're never going to see a competitive ARF but you'll find ARFs that fit the class.

To be honest message Greg. I think he is very modest in his fees and from what I can see his building is very good. In addition he seems to be a very nice guy, which is more important in my book.
Aug 22, 2016, 02:32 PM
Flying = Falling (Slowly)
dharban's Avatar
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Originally Posted by ZAGNUT View Post
"The wood parts of the fuselage may be reinforced on their surface with GRP/CFRP/Kevlar.".....pretty much allows balsa cored composite construction so probably isn't interpreted correctly. the way i read the rules it is allowed only on the outside surface of the fuselage and only as a finish, not as any type of structural reinforcement. would probably be wise to even drop the carbon and kevlar.
I agree with what you are saying here, but this part is pretty much of a clear translation as far as I can tell.

Given the very light weight to which these things are being built, I have a hard time seeing how an advantage might be gained by using some kind of composite overlay. That being said, if it were my rule, I would not allow overcoating with anything other than either covering material or paint. The light weight of these planes means that they "land light" and I have a hard time seeing the necessity of "reinforcement".

On one hand, if there is interest in this class, it will become useful (if not important) to not go too far in reinventing the European rule given the robust availability of suitable kits from there-- and on the other hand to not back away from improvements or clarification which suit our sensibilities. After all, it will be a long time before this approaches International status. And the basic idea of the class should encourage, to some degree, experimentation and innovation.

Happy Landings,

Don
Aug 22, 2016, 03:56 PM
Sagitta Fanboy
Quote:
Originally Posted by dharban View Post
I agree with what you are saying here, but this part is pretty much of a clear translation as far as I can tell.

Given the very light weight to which these things are being built, I have a hard time seeing how an advantage might be gained by using some kind of composite overlay. That being said, if it were my rule, I would not allow overcoating with anything other than either covering material or paint. The light weight of these planes means that they "land light" and I have a hard time seeing the necessity of "reinforcement".

On one hand, if there is interest in this class, it will become useful (if not important) to not go too far in reinventing the European rule given the robust availability of suitable kits from there-- and on the other hand to not back away from improvements or clarification which suit our sensibilities. After all, it will be a long time before this approaches International status. And the basic idea of the class should encourage, to some degree, experimentation and innovation.

Happy Landings,

Don
I think some of the need is for repair work. Bust a pod and a strip of carbon on each side is a solid & light reinforcement when repairing.
Aug 22, 2016, 04:04 PM
Sagitta Fanboy
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Originally Posted by Bmwjoon View Post
You're never going to see a competitive ARF but you'll find ARFs that fit the class.

To be honest message Greg. I think he is very modest in his fees and from what I can see his building is very good. In addition he seems to be a very nice guy, which is more important in my book.
I suspect that an ARF version of one of the German or Turkish kits will be competitive here in the short term, simply due to the limited availability of kits optimized for this ruleset.

Given the need to buy from overseas or scratchbuild to get a 16oz 2m woodie today, an 20-24oz ARF based on those designs would likely be competitive against the 24-32oz 2m designs that are readily available over here.

I suspect we'll see some truly world-class designs show up soon enough and the competitiveness of such an ARF end, but the reality is that if you want a competitive 2m woodie without dealing with shipping Germany (and possibly long wait times for productions), you're going to buy a Chrysalis or Duet and deal with the fact that a model stressed for winch launching will be overweight for F3-RES (And that's not a knock on these models, they're designed for a different set of constraints than F3-RES optimized designs, you aren't going to winch a Slite, even gently). But you're also likely to be mostly competing with designs ranging from a GL to other Chrysalis or Duet, at least until some more optimized designs start showing up over here.
Aug 22, 2016, 09:40 PM
Registered User
dharban:

Thank you very much for the improved English version.

We here in Albuquerque are having a very good time with these airplanes, and intend a contest in November 2017 (yeah, we have to plan waaaay ahead). We intend to use the Albuquerque Balloon Fiesta Park, which is an outstanding venue for RC soaring.

As far as ARF versions, there is one we have tried: the RESi. Roughly $300 delivered from Germany, it flies fine, but achieves performance by applying a large wing area to make up for a bit more weight. Mass construction techniques also mean more parts exposed to the air, which increases drag a bit.

The kits we've tried so far (PuRES, Slite, X-RES) all deliver great performance for ridiculous weights (typically 14-15 ounces) and build well into straight airplanes with good strength. With the six or eight different designs (and manufacturers) available, we find delivery to be between ten days and several months. However, the wait of several months has always been made known to us by the different builders, and we still find that delivery is when promised. At least one vendor in the UK is now on board, and his delivery times are roughly ten days. I compare that to delivery of servos advertised as "in stock" from a vendor here in the US, who has had my order for four weeks, and is "about to ship" any day.

We are still on the lookout for a hi-start that at least approximates the specifications in the F3B-RES rules.

Yours, Greg
Last edited by glidermang; Aug 22, 2016 at 09:46 PM.
Aug 30, 2016, 05:59 PM
Registered User
I have just discovered this F3-RES class! I'm living in Europe, all my flying was in the US and Canada and I even brought a couple of 2M models with me ... but they are rather heavy (a mouldie and a Spirit). Winching the Spirit had to be done very gently, just tapping the switch, but these Drela-inspired F3-RES types are probably much stronger even in very light versions. The weight is very important, because where I now live models have to be less than 600g to fly in controlled airspace, although obviously contests are held in open spaces. So for practice/sport flying in a built-up area, this class is very appealing, if DLG is not one's cup of tea.
Aug 30, 2016, 11:58 PM
Registered User
Gentlemen
If this new interpertation is correct, the only restriction on the H/S rbber is Pull, not dimensions. Right?
JDK
Aug 31, 2016, 07:42 AM
Flying = Falling (Slowly)
dharban's Avatar
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Originally Posted by big jer View Post
Gentlemen
If this new interpertation is correct, the only restriction on the H/S rbber is Pull, not dimensions. Right?
JDK
No.

The rule clearly specifies that the length of the rubber portion shall be 15 meters plus or minus 0.5 meters that, when extended to 45 meters, shall not exceed 4 kg of pull.

Happy Landings,

Don
Sep 02, 2016, 05:12 AM
Sarven Bedikoglu
sarvenn's Avatar
In Turkey we do not limit the extended lenght pulling force.
Silicon or rubber bungee lenght is limited to 10 meters.
Braided elastic rope lenght is limited to 30 meters.
Fishing line (monofilament, dynema-spectra, kevlar etc lines are forbidden) lenght is limited to 100 meters.
From stake to maximum streching line, which is also the border of safety coridor, is 170 meters.
You may see the illustration below for the other dimensions as well.
If you have any questions please do not hesitate to ask.

Keep in mind that regular competitions with an official rule book is being help for 11 years in Turkey. We, as 2 meter RES community in Turkey, have such a big experience. While doing revision to our rule book we also examined F3J and AMA 2m RES rules as well. In the end the rule book became quite mature after so many discussions among the official model gliding clubs in Turkey, including our beloved German friends (Philip Kolb and Reinhard Vallant).
Sep 04, 2016, 08:25 AM
Flying = Falling (Slowly)
dharban's Avatar
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Quote:
Originally Posted by sarvenn View Post
In Turkey we do not limit the extended lenght pulling force.
Silicon or rubber bungee lenght is limited to 10 meters.
Braided elastic rope lenght is limited to 30 meters.
Fishing line (monofilament, dynema-spectra, kevlar etc lines are forbidden) lenght is limited to 100 meters.
From stake to maximum streching line, which is also the border of safety coridor, is 170 meters.
You may see the illustration below for the other dimensions as well.
If you have any questions please do not hesitate to ask.

Keep in mind that regular competitions with an official rule book is being help for 11 years in Turkey. We, as 2 meter RES community in Turkey, have such a big experience. While doing revision to our rule book we also examined F3J and AMA 2m RES rules as well. In the end the rule book became quite mature after so many discussions among the official model gliding clubs in Turkey, including our beloved German friends (Philip Kolb and Reinhard Vallant).
With no disrespect to the rule you have been flying with for 11 years, it would result in drastically different planes and flying than the German rule. (I am not suggesting that the German rule is better -- only different.)

I have observed many times in various forums that the rules ultimately design the planes. Right now, the German rule limits the pull to 4 kg and effectively, the maximum potential energy contained in the extended elastic system to about 60 kg-m (586 watt-sec). At least theoretically, a similar elastic reduced from 15 meters to 10 meters and stretched to 70 meters would have 12 kg of pull and maximum potential energy of 360 kg-m (3582 watt-sec). It is not at all unreasonable that a heavier elastic could have 24 kg of pull and 720 kg-m (7056 watt-sec) of potential energy.

It is not necessarily a bad thing to leave the rule open ended as to pull, but given the history of F3J, it suggests that in a highly developed competition under these rules, competitors would surely explore the limits of benefits that could be realized by exploiting this aspect of the rule. It is not much of a leap of faith to believe that the hi-start that we envision could evolve into more of a catapult designed to enhance the zoom capability of the plane.

In any event, the German planes that we are admiring here are optimized for low pull, low energy launches. And the apparent trend toward lighter planes suggests to me that a launch rule with no restrictions on pull and/or total energy would not fit these planes.

As I observed, the rule designs the plane and the light planes we are seeing in abundance out of Germany are a product of the limitations on pull and total energy. Change the limitations on pull and total energy and these planes would likely not work as well.

Happy Landings,

Don


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