Removing the weight limit?? I do not think this is a good idea. It would likely lead to heavier gasoline powered biplanes. A 6,5kg gasoline biplane with plenty of power would be a more “stable” airplane and present better.

Removing the size limit. I can’t believe anyone seriously is suggesting this. Bigger, heavier and more EXPENSIVE is not what we need. It’s difficult enough already to transport the airplanes for the large events (WCh, ECh, etc).

The only problem I see with the current weight rule is the injustice between electrics and ic power. The fact that glow airplanes are allowed to takeoff at a higher weight is not good. It also makes the already expensive electric airplanes more expensive since they are more difficult to get below the weight limit (without the top bling bling products).

Here is my suggestion. Instead of having a “dry” weight limit, set the limit to a maximum takeoff weight. I would say 5,5kg. Yes it may sound difficult at first, but if the weighting is done at the flight line it should not add much more complexity for the organizer. At large events airplanes are randomly weighted after the landing (to control the <5kg limit). The scale is already there. I would instead suggest that before takeoff the airplane is weighted (say 2-3 pilots ahead of your start). The pilot should not be aware of the readout on the scale. If the weight is over the limit the pilot should still complete his flight (similar to how the sound test works). Later the jury decide what to do. Either disqualify the flight or, perhaps more appropriate, subtract points from the score of that flight accordingly to a given “punishment” scale.

Having a maximum takeoff weight would, in my opinion, make it fair between electrics, gasoline and glow setups.

/David

Keep the weight limit; eliminate the size limit. No concessions for electrics. Did we learn nothing from the rule change allowing 20cc 4-strokes, but only 10cc 2-strokes? Besides the great incentive for manufacturers to develop high performance 1.20 4-strokes.
If size and cost are a concern then that ship has already sailed. Current pattern designs are big and expensive, but pattern has moved in the same direction since the inception of the FAI F3A world championships in 1960: bigger and more expensive. Back in the '60s the engine displacement was increased from 7.5cc to 10cc (cost at least one manufacturer a bundle as he'd geared up production for a high performance .45) and designs got bigger as more horsepower was extracted from the 2 stroke 60. 60 sized pattern ships grew to 850"sq and 66-68" long with the release of the Hanno Special and YS .61AR. Along came the 4-stroke. Not too impressive at first, then YS released the 1.20AC and designs got bigger, like Dave Von Linsowe's USA Star which was considered HUGE at the time. Levelling the 2-stroke versus 4-stroke playing field; displacement restrictions for both were eliminated, but the 2m size restriction was added. The result of the 2m rule was that everything was designed to 'fill the box' which meant increased power was required. We're now looking at the YS 1.70, OS 200 and the OS 1.60FX as the optimum glow power plants. Electrics have made incredible progress and seem to be competitive at present, but will certainly get better. You can now spend $5-8,000 on a top-of-the-line pattern ship without radio. The nature of competition is to push the envelope as far as the rules will allow, regardless of cost. There's an old auto racing axiom: speed costs, how fast can you afford to go? Paraphrasing for pattern: accuracy costs, how precise can you afford to fly? The best pilots in the world are simply striving to find the best 'tools' to help them achieve victory. There is still no substitute for effective practice.
Personally, I wish the rule had simply been changed to allow a displacement increase to 15cc for any glow engine (back in the '80s).
Pattern is still, by far, the most intriguing SIG in R/C - at least for me

PS - I would love to hear Wolfgang Matt's thoughts about pattern as he is clearly the elder statesman of the sport having competed in every F3A WC since at least 1971!!

Hey Chad,

There are some top flyers, by this I mean perhaps in the top 20 in the US, which advocate speed and believe electric can not produce the speed needed in the wind. I'm not going to pick a side on this, but I like my electric speed. I think it's find for all but 5% of any conditions. I think electric has gone through / is going through a transition period of sorts, as many flew very slow and found the wind to be an issue. There is 'too slow' and I think we approached this limit. As new props and motors were developed, I think this is less of an issue now.

You state, "in fact most guys were flying setups that are slower than today" which sort of goes to the above point that maybe we were getting too slow ? If most were slower than today, these pilots are flying faster for some reason (today).. they have learned that there may be too slow.

Good Luck at this year's Worlds.

sc

Scott,

I'm sure there is "too slow" but what about too light? Any of you top 20 guys believe a plane can be too light? It sounds like maybe 5 KG is some magic weight for a pattern plane?

Jim O

Top 20, well, maybe in Masters. But yes, I believe there is too light. (I am thinking this right now with my Abbra. )
Too light in the wind that is. With no wind its great.
With lightness comes losing strength in the plane.
I would rather weigh 12 lbs with a bigger bodied plane in the wind, 10 lb without the wind.

Chad, (don't take this wrong, I'm just asking as I don't know) obviously I'm not a regular at the nats as I can't really afford to go, so explain to me who Skinner is and where in the rules it states that you can't have a fuel tank in a pattern ship. Maybe in Fai they have a rule, not sure. Not sure about ama classes either.
As for putting a fuel tank in my electric, I can do it regardless if it doesn't weigh more than 5000g right?? What's the difference.. If I want to put a block of cheese in my plane, I can. As long as it is under weight, right?? They can't limit if I have a fuel tank in my silly little opinion..

It seems unfair that a glow plane can put as big of a tank in as they want to penetrate better. I know people running too large a tank on purpose. Maybe they should limit the fuel tank size also. Or at least how much fuel you can weigh with.


I think there the rulebook needs to be rewritten for glow and electric.
Lots of changes have happened in the last few years and they need to realize that and make some changes.
I know of a few folks local who would fly pattern, but their planes won't make weight. So they don't bother.
It's a shame for our sport.

Either way, new rules, old rules, my plane makes weight so at this point, it doesn't matter. But I would like my plane to be heavier.

Good luck to all at the nats!! Wish I was going..

Chris

Chris,

They is you and me! Any AMA member can submit a [link=http://www.modelaircraft.org/PDF-files/333.pdf]rules proposal[/link]. You just need one other open member and a CD to endorse it. The contest board then votes on those proposals on behalf of their 'constituents'. It's that simple. (Just make sure you let your CB rep know how you feel!)

Scott

So, take a page from the slope glider pilots and build some ballast blocks to take it up the weight limit in several steps and fly it that way. There can't be any rule against adding ballast up to the weight limit...

Mark

Hi Chris

Bob Skinner is the F3A sub-committee chair, so this only applies to FAI. Not sure how the AMA would interpret the rule for the rest of the classes. For the Canadian classes we weigh without batteries (except FAI obviously), and have no voltage limit so its really not an issue here. You can have a fuel tank at the Worlds lets say, but since its not providing a propulsion source (the spirit of the rule!), then it would need to be full when weighing an electric plane. Its not clearly defined so it depends on who and how the rule is interpreted!

Up to 5kg's, you can do as you please However instead of filling up the extra weight with dead weight why not carry more capacity?...other than cost.

Biggish, yes, expensive, if you want it to be. Personally I just don't buy the whole "pattern has gone so big and expensive it is putting people off" argument. You only have to look at the people with large scale, expensive IMAC petrol jobs in the UK alone to see that just isn't the case.

Your last sentence sums it up. Plus an expensive model doesn't necessarily mean more points, far from it. Look how far CPLR got on a shoe string - pretty god dam far. And his models are still pretty modest today compared to some. Home made wings/tail/rudder, composite fuz yes but hardly costing a gazillion pounds and regular YS etc etc.

If the FAI really wanted to curtail costs then they would have to introduce measures such as:

1) minimum weight
2) raise the max weight to allow the cheaper slighter heavier kits to be viable + petrol engines
3) fuel restrictions perhaps as they do in pylon?

Personally I think F3A planes aren't too bad as they are size wise etc (2m is quite big enough). Just the rules need tweaked slightly to allow it easier to make the weight limit with an el cheapo model.

Loopholes.. That's kinda what I'm saying.. I know we've discussed this one before anyway...

I agree, more capacity for weight.
At this point that's what I'm looking at, new batts. Just gotta figure out how to swing it with the wife. LOL


C

Angus, I didn't want to introdue the IMAC argument, but they can sure spend a LOT of money on their airplanes!! I agree, you can build/fly a competitive pattern ship for much less than $8,000 (especially if you build it!!) and I don't think cost or size has deterred anybody from participating. The larger pattern ships may be more of an attraction today!

How long has the 5Kg limit been in place? Since the original rules?

How much does an electric propulsion system weigh (motor, speed controller, battery, motor mount, and any other paraphernalia)?

How much does a glow propulsion system weigh dry (YS 1.70, mount, exhaust system, tank, fuel tubing, fuel dots, mounting accessories for exhaust sysem, etc)?

Don Lowe wrote an article about weight and pattern ship performance (especially in regards to damping in 'heavy wind'). He concluded that lighter is better. If current designs need to be light for calm conditions and ballasted for wind, then perhaps a better design is required...

First of all there are not many 2-M $500 or less airframes PERIOD wood -composite- silk&dope or anyother material
Secondly I see statements like this all the time BUT you can easily convert a Focus to electric and make weight. It's been done by a club member here in Louisiana more than once. And Dare I say this [:@] { You can purchase a $329.99 ARF and make weight with all but the heaviest electric setup available} I did it . The choices are there , allbeith not a lot of them. But that isn't a good argument against electric or reason for a rules change.

Eddie

Hacker A60-20S
TP Extreme 5000s
Castle 85HV, low timing
APC 18x12PN (repitched by me)
7800 RPM @ ~90F, 75' MSL

Neu 1515-1.5Y 6.7:1 BAM PG
TP Extreme 5000s
Castle 85HV, high timing
APC 18x12.75PN (repitched by me)
8000 RPM @ ~90F, 75' MSL

Lighter always flies better. Wingloading can be too light (use a smaller wing!). Electrics have there advantages as do glow......if glow is perceived to have an advantage in 5% of the windiest conditions.....there is the other 95% of the time when electric has the advantage? Yes, the rules would not seem to be fair in that glow can exceed 5KG at takeoff and electric can not. But I would never support a weight increase for electrics as they are clearly competitive now, and will be increasingly so as they continue to develop at a very rapid pace - giving electric a rules advantage would pretty much obselete current day glow setups. I would absolutely support a rule change stating 5KG takeoff weight for all aircraft (heck my glow stuff was 4.75KG at takeoff).....and that would have also have the effect of obsoleting most glow stuff.

Regards,

Dave Lockhart

I disagree.

How many pattern pilots still design their own aircraft? most will go and buy either an ARF or approximation of (i.e. an oxai, it is still technically an ARF) so the package is suited to what the original designer was chasing.

Everyone here will agree that a large plane is better for presentation so the 2m limit is good, but at the same time, this can be messed with, and there is no lower limit, so effectively you could fly with a 5kg 40 sized model.

I'm currently building a ship expressley around the MVVS 160, because I couldn't find anything I liked. It's not 2 x 2 but you'd be hard pressed to tell the difference. By doing this I'm looking at less dead weight (smaller plane) and a better power to weight ratio than if I'd stuck with a 2x2.

The chinese have the same word for problem as they do for opportunity...

I am of the belief that there can be 'too light' and this would show itself in windy conditions. I believe, and this may be my own preference, that a light, say 10lb airframe will not fly as well as an 11.5lb airframe in the wind - and by this I mean wind gusts will affect the 10lb plane more than the 11.5lb plane. Way back when.. (about 10 years ago) there was too light, and this was easy to tell as the airframe was not ridged - there was to much flex in it, between the wings and the stab. Now, with newer technology, I think this flex is gone (yet we see Beryll's being stiffened to prevent twist), but I could see how it might be a problem if you were trying to build a 8lb plane, 2M plane, just as an example. I suppose the leads to, if we raised the weight limit to 13lb, does the plane have an advantage over an 11lb plane in the wind? Perhaps it is in the thumbs?

sc

If you're thinking moments of inertia, theres a good and a bad side to all of that.

A heavy aircraft won't get knocked around by wind as badly as a light ship, but anything it does get knocked by is going to take more force and more time to correct.


And not every competition is in 30k wind is it?

What's broken is the fact that glow has the option to takeoff over 11 lbs and electric is limited to 11 lbs.

So with that in mind, how about a new max weight of 9 lbs without batteries for electric powered models?

Very well put Scott.. We electric guys don't have the Option to take off over 11 lbs.

BW

I thought we're flying pattern, not handicap golfing or bracket racing or "asking for lengths" ala Pinks. Everybody knows the rules coming in and has the opportunity to choose powerplants and airframes accordingly. If people want to fly electric or gasoline or steam... that's great. But don't ask for special treatment because your steam engine can't make weight. People have the choice to fly $5000 professionally built composite models or $1000 home built balsa ones. Is somebody going to start lobbying for dollar limits on the planes, to keep things "equal" ?
--Derek

I heard that dilithium crystals are quite light for their size...much better alternative power source to steam power

Rules drive technology.

Rules drive technology

Yeah? Go tell that to Ferrari F1 racing development team - hahaha

Agreed. But obsolete rules (or rules that flat out don't make sense) can be changed. Nothing is cast in stone. Just look at scored takeoffs and landings!

Things aren't equal with the current rules today...that's my point. Simply put, I have a problem with the fact that one plane can takeoff at 12 (or more) lbs and another cannot in the same event when weight limits are supposed to be an "equalizer".

Maybe there is no "better" solution to the weight issue than what we currently have, but that shouldn't stop up from discussing other options. That's all this is after all...a discussion.

Like I said earlier in this thread(I think), what about:
For I/C models----5 Kg. max ,less fuel (as now-- so no worries re redundant set-ups)
For Leccies-------5Kg. max, less batteries powering the motor.

my mind says - electric flight - keep it light...mabe I'm wrong

but I am definitley not going to build an electric plane exactly to the weight limit whereas I will do that with an IC plane. IC fuel don't run outta amps till the last drop you see - no matter how modern the battery is!!!