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F3A Two Meter Rule

Old 04-21-2011, 11:32 AM
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proparc
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Default F3A Two Meter Rule

When did the FAI two meter\5 kilo rule come into effect and, what exactly brought about the need for the rule? What was going on prior to the rule, that the rule was needed and implemented?

If the rule was not in existence, what would modern Pattern ships look like today based on the existing schedule.
Old 04-21-2011, 03:49 PM
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Stuart D
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Default RE: F3A Two Meter Rule

I dont know the why, when or where as far as the rules go but the patterns today seem to match the

power available and the planes are made to fit the combination of the two . If that makes sense .

As far as " what would modern Pattern ships look like today based on the existing schedule"

I think a better question would be:-

Given the motors and engines we have available what would we want to have as a pattern plane ?

We all know that power to weight is a given so its just a matter of size .

For me coming from IMAC I think some of their planes have gotten too big and "presentation"

has suffered as a result .

I think if pattern were let off the leash the planes would end up closer to 2.1 to 2.2 and nitro

would be a thing of the past . 40 to 50cc petrol and electric would be the way and also

the wing span would be set to one size only (span) .

Just my thoughts .

Stu
Old 04-21-2011, 04:24 PM
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speedracerntrixie
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Default RE: F3A Two Meter Rule

Im not 100% sure but I was once told that the 5K weight limit was based on what you could check in as baggage on an international flight.
Old 04-21-2011, 04:57 PM
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Default RE: F3A Two Meter Rule


ORIGINAL: proparc

When did the FAI two meter\5 kilo rule come into effect and, what exactly brought about the need for the rule? What was going on prior to the rule, that the rule was needed and implemented?

If the rule was not in existence, what would modern Pattern ships look like today based on the existing schedule.
Imagine a 3 meter pattern plane with a 170 cc motor....
Old 04-21-2011, 05:39 PM
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Default RE: F3A Two Meter Rule

I am not sure of the exact time. But I am thinking early 90's. It had to do with engine displacement. At the time they only had a limit on engine size. .61 cu.in. or 10cc and no size or weight limit. Then along came the four cycle engine. It did not make the same power for the same size displacement. So the changed the rules to allow the 4 cycle to compete. Giving it twice the displacement. 1.2 cu.in. Lo and behold the 4 cycle evolved and now makes more power then the little .61 2 cycle. As you guessed it the 2 cycle can't compete any more. (A little side note. A decade or so later the exact same thing has happened in motocross. Go figure!) So they remove the engine size limit and put in a size and weight limit we have to day.
Old 04-21-2011, 06:27 PM
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Default RE: F3A Two Meter Rule

It wouldn't matter what they would look like if the limitations were dropped.
Last time I looked, most "2 metre" airframes were actually quite a way off taking advantage of the full 2 metres (maybe it is weight related though)

I think that if the limitations were lifted there would be a lot of threads telling people how you need to use XXX brand of engine and a bigger plane - just like the IMAC scene seems to have degenerated into (ok - I am speaking more from experience downunder).

Meanwhile (to the uninitiated) both remain "boring" sports to non competitors.

waiting waiting
Old 04-21-2011, 06:37 PM
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Default RE: F3A Two Meter Rule

The 2 meter rule became effective in 1996.  Prior to 1996, the size of pattern aircrafy was essentially limited by the engine limitation, 0.61 ci 2 strole and 1.20 4 stroke.  The 1996 rule change allowed any engine displacement but limited the length.span to 2 ,meters and the total weight to 5 kg.  Nobody I've talked to knows exactly where 5 kg came from.  I've heard that it's a carry-over from an old FAI free-flight rule.  Not sure if that's ture or just an urban legend.


Rob
Old 04-21-2011, 07:09 PM
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burtona
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Default RE: F3A Two Meter Rule

It's my understanding that the FAI 5 KG weight limit has been around since the 30's, but I wasn't around then so I wouldn't bet the house payment on it.
Old 04-21-2011, 10:04 PM
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Default RE: F3A Two Meter Rule

the 5 kg limit existed in FAI F3B since the 80's...

and many RC Speed/distance/duration fai "World Records" must be with a 5 kg plane...
Old 04-21-2011, 10:39 PM
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Default RE: F3A Two Meter Rule

FWIW FAI changed the maximum weight for F3C helicopters to 6.5 kg (14.33 lb) in 2009.

The maximum battery voltage was changed to 51 volts. This allows for 12S battery packs.

So the FAI can, and will, make changes when the majority of participants want the changes.
Old 04-21-2011, 11:14 PM
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proparc
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Default RE: F3A Two Meter Rule


ORIGINAL: Stuart D

I think if pattern were let off the leash the planes would end up closer to 2.1 to 2.2 and nitro

would be a thing of the past . 40 to 50cc petrol and electric would be the way and also

the wing span would be set to one size only (span) .

Just my thoughts .

Stu
What you are saying then is that, the 40 to 50cc petrol size would voluntarily limit the wingspan?
Old 04-22-2011, 12:12 AM
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Default RE: F3A Two Meter Rule

Unless the top sponsered flyers were using 50cc petrol engines in ANY sort of F3A ship regardless of the size/weight, then very few non-sponsored flyers would want to use them.

De-restricting the engine rule made every engine greater than .61cu two stroke and 1.20cu four stroke available to be used (to lower the costs, of course) but it seems that sweating on YS's latest offering is the fashonable thing to do.

At least electrics have the edge so far in that you can get a cheap motor and there's a really good chance it will "idle" well, "transitition" smoothly, have plenty of bottom end torque, draw it's "fuel" from the pack placed behind the firewall or on the COG, and run consistantly no matter how high above sea level your next comp is at. It's unfortunate that you need a specialised IC motor to achieve similiar running qualities.

F3A ships are far from purpose designed, the F3P planes are where F3A designs need to head but the change has to happen slowly so it's easier for the community to accept..
Old 04-22-2011, 02:52 AM
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Default RE: F3A Two Meter Rule


ORIGINAL: proparc
What you are saying then is that, the 40 to 50cc petrol size would voluntarily limit the wingspan?
No , IMHO the span is an ideal size and the engine would follow suite .

Stu
Old 04-22-2011, 06:35 AM
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Default RE: F3A Two Meter Rule


ORIGINAL: Stuart D


ORIGINAL: proparc
What you are saying then is that, the 40 to 50cc petrol size would voluntarily limit the wingspan?
No , IMHO the span is an ideal size and the engine would follow suite .

Stu
Before 1996, before the 2m-5 kilo limitations, there were several good sources of model kits all of which were reasonably priced at around 400$ give or take. And the Japanese wood kits by Kato and Yoshioka (both superb) were in the 300 range as I recall. The models were powered by 4 stroke YS's mainly which typically cost as much as the plane kits did.

Today, the sources have come down drastically, and cost has gone up 5X for a plane kit (ARF actually). Notwithstanding the latest efforts of two potential suppliers being discussed in RCU which promise reasonable cost, we've been in this higher escalating cost spiral that will always persist because we demand the extreme precision in the airframes.

In my view, change the existing rules and chances are better than average that the cost would escalate too. And IF that happens, watch the Pattern numbers drop even further. It probably will not kill the sport, but I think the market for the new offerings would dwindle enough such that no manufacturer would have an interest in staying in it.

What I'm saying is be careful what you wish for.

On the other hand, if I were to speculate, a 50-60 cc gas engine is capable of around 6HP today. That much power, assuming the engines were ported to give us mid range grunt with better carburetion than a walbro, would work very nicely in a model weighing 16-17 lbs give or take. As far as size, you can pack a lot of size in that weight....I'd take an educated guess and say 90-95" box. It would be very sporty...................
Old 04-23-2011, 03:13 AM
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Default RE: F3A Two Meter Rule


ORIGINAL: mithrandir


ORIGINAL: proparc

When did the FAI two meter\5 kilo rule come into effect and, what exactly brought about the need for the rule? What was going on prior to the rule, that the rule was needed and implemented?

If the rule was not in existence, what would modern Pattern ships look like today based on the existing schedule.
Imagine a 3 meter pattern plane with a 170 cc motor....
That would probably be spectacular!!
Old 04-23-2011, 04:32 AM
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Default RE: F3A Two Meter Rule

Imagine a 3 meter pattern plane with a 170 cc motor....
There's already something very close to that if you want to give it a shot: a DA-powered Carden Extra on low rates.

In my very humble opinion, as a guy who just last year got into pattern and is just starting to catch his breath, current state-of-the-art is pretty darn good and is still showing a lot of innovation in airframes, power plants and R/C equipment. At the same time, a few manufacturers have just worked out a production cost formula that will bring affordable packages to more of us and keep them in business, if only barely in this current economy. Let's not mess with that.

Another factor for me, and I suspect a lot of others, is the issue of transporting models to the practice field and to contest venues. Pull into the parking lot at a big IMAC-oriented club and you'll see what I mean... a lot more large vans, big SUV's and trailers.

And as usual, the great pilots and those who practice their craft will rise to the top no matter what equipment options or restrictions are specified by the rules.

As Matt said above, change the rules now and watch even more guys walk away from competitive pattern.

If you are not happy with pattern in its current state there is a solution: Go fly IMAC.
Old 04-23-2011, 07:39 AM
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Default RE: F3A Two Meter Rule

I think what happened is that the power to weight ratio of engines went up, more powerfull engines came available. An unrestricted F3A class would become a 'battle of the biggest wallet', so they restricted size to 2m. Something like that.

There's a trick to the weight, which fuel flyers abuse, and that's the fact that a IC powered plane is weighted with an empty fuel tank. So you can put in a tank of 1.5 litres and fly with 1kg fuel ballast in heavy winds. Electric flyers don't have this advantage. Offcourse, if a contest happens to be in wind-free conditions, this is useless, but ie CPLR has benefitted from this the last WC/EC.

I do think the 2m rule is good, I have no idea how this is setup world-wide, but here in the netherlands we also have F3A-X, for planes bigger than 2m.

The 5kg rule makes no sense, they should just abandon it.
Old 04-23-2011, 07:51 AM
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Default RE: F3A Two Meter Rule

ORIGINAL: cmoulder

There's already something very close to that if you want to give it a shot: a DA-powered Carden Extra on low rates.

[link=http://www.giantcircus.com/Super_Extra/SX.htm]http://www.giantcircus.com/Super_Extra/SX.htm[/link]


[link=http://www.giantcircus.com/Videos/SX-Cable-2009.wmv]http://www.giantcircus.com/Videos/SX-Cable-2009.wmv[/link]



[link=http://www.giantcircus.com/Videos/FASST-3W-AW_Su29-Duralite.wmv]http://www.giantcircus.com/Videos/FASST-3W-AW_Su29-Duralite.wmv[/link]



I am pretty familiar with how a 40%'er flies... and the trailers and other supporting equipment needed....
They stretch the 10% rule enuff they fly very nicely....

He he he he

... though I am not involved in IMAC, (yet??).... there seems to fairly regularly be 40 to 50 participants at the west coast IMAC contests I have
known about.... compared to the 20'ish to 30'ish participants (I think is) typical of a pattern contest... I would suggest there is something
more appealing about IMAC.. (?? MAybe??)

I also find it interesting that 40% ARF's that fly pretty dang good can be had pretty easily for under $1500.00
Yet a good pattern plane is very 'xpensive....

be interesting to see if the Vanquish, due to a more reasonable price, will bring in more participants...

( I don't think I mentioned I wasn't happy with the current state of Pattern... other than planes being 'xpensive :O )

allowing pattern planes to get larger (Like 3 meter 40%'er size) certainly would add expense to the International FAI Crowd!!



Old 04-23-2011, 08:18 AM
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Default RE: F3A Two Meter Rule

( I don't think I mentioned I wasn't happy with the current state of Pattern... other than planes being 'xpensive :O )
I guess my (incorrect) interpretation derives from the fact that the "imagine a 3 meter pattern plane" could be taken to mean "I wish pattern rules would premit" or simply "imagine just for the heck of it".

IMAC airframes might be comparatively cheap on a pound-for-pound and inch-for-inch basis, but everything else about them is more expensive, except for fuel if one is flying glow in pattern.

Old 04-23-2011, 09:17 AM
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Default RE: F3A Two Meter Rule

There has been two attempts to control spiraling costs in F3A, one of which was successful.

In 1981, Hanno Prettner won the World Championships in Acapulco with the most advanced plane of it's time. The Magic featured three leg retracts, flaps, airbrakes, wheel brakes (landings were judged), in-flight mixture control, internal pipe and radio controlled variable pitch propeller. Nobody apart from the exceptionally well off could afford such a plane, let alone build one. In Florida in 1983, Hanno decided enough was enough. He built, flew and won with the Calypso. It was a taildragger, had an underslung pipe and sidemounted engine, and that was it. Winning with his "trainer", Hanno effectively ended the race for ever more costly models, allowing more beginners to become competitive with cheaper models.

In the 1980s, the only competitive engines were purpose-built piped .61s like the OS Hanno and YS 60. They were extremely expensive. In todays currency, they would cost double that of a YS 170 setup. In the 1990s (The Saphir-Era) The YS 120 FZ and OS 1.20 with supercharger started to dominate. They were even more expensive.

The 2-meter rule came about as an attempt to remedy the situation. By letting go of the .61/1.20 max displacement rule and instead limiting wingspan and weight, the idea was that you could fit a very cheap 1.20 or even .91 two stroke with stock muffler and have lots of power. Then the OS 1.40/Hatori 900 combo came out, YS responded with the 1.40 DZ and the race is still on. Today, you really "need" a Powerbox digiswitch, Hacker geared motor, Thunderpower cells, ESC's with variable radio controlled braking, cooling fins and enough cooling ducts inside your cowl to make formula 1 look like childs play. Add a counter-rotating propeller or geared belt-drive, and you've effectively excluded all but the most dedicated from even thinking about starting in F3A. Oh, and did I mention you need to have a carbon-shell-painted-in-the-mold plane hand made in the Czech republich just to make weight with the 15 kg/cm digital brushless S-bus servos and 37 volt batteries you need to be able to snap AND accelerate while going vertical?

Now, even a year-old model is discarded as old-school and uncompetitive. Who will show up with an Integral this year?

What the world needs is another Hanno who can win the World champs by good margin, flying a home made balsa plane fitted with nothing but Hobby King motors and batteries. And such a plane would not have a canalizer...
Old 04-23-2011, 10:27 AM
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Default RE: F3A Two Meter Rule


ORIGINAL: Jon Wold

What the world needs is another Hanno who can win the World champs by good margin, flying a home made balsa plane fitted with nothing but Hobby King motors and batteries. And such a plane would not have a canalizer...
Really great post!! Sounds like a job for Andrew Jesky.
Old 04-23-2011, 11:02 AM
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Default RE: F3A Two Meter Rule

+2 Love the post. truth in every Letter!
Old 04-23-2011, 11:55 AM
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Default RE: F3A Two Meter Rule

Bravo Jon!

Alejandro P.
Old 04-23-2011, 12:06 PM
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Default RE: F3A Two Meter Rule

It's just how crazy people are willing to be. I competed in the netherlands last year with the Sebart WindS 110, a 400 dollar airframe, and got pretty decent results, without canalizer. The year before that, the final was won by Derk van der Vecht flying a Miss Wind .50, with hobbycity servo's and engine.

True, he wouldn't take that to the WC or EC, let alone win with it, but at entry level the biggest misstake, I think, it that 'it has to be 2m'. With a slightly smaller airplane, like the WindS 110, you can start flying F3A and go all the way up to masters before it starts being a real disadvantage.

This year 2 top-5 flyers (over here) will compete flying a home-built Miss Wind 140 'look alike'.
Old 04-23-2011, 01:39 PM
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Default RE: F3A Two Meter Rule


ORIGINAL: hezik

I think what happened is that the power to weight ratio of engines went up, more powerfull engines came available. An unrestricted F3A class would become a 'battle of the biggest wallet', so they restricted size to 2m. Something like that.

There's a trick to the weight, which fuel flyers abuse, and that's the fact that a IC powered plane is weighted with an empty fuel tank. So you can put in a tank of 1.5 litres and fly with 1kg fuel ballast in heavy winds. Electric flyers don't have this advantage. Offcourse, if a contest happens to be in wind-free conditions, this is useless, but ie CPLR has benefitted from this the last WC/EC.

I do think the 2m rule is good, I have no idea how this is setup world-wide, but here in the netherlands we also have F3A-X, for planes bigger than 2m.

The 5kg rule makes no sense, they should just abandon it.
Not correct.
There is nothing to stop an electric model having a fuel tank to carry fuel as ballast.

Brian

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