OhD

There has been a lot of talk about changing the weight requirements to create a level playing field between IC engines and electrics. Suggestions range from adding up to a pound to the current maximum limit to weighing glow planes all fueled ready to fly.

It seems to me that with the current rule the electrics have the advantage. The pilot with the YS 1.60 adds about 18 ounces of fuel meaning he'd have to build a nine and a half pound (dry) plane to equal the eleven pound electric at take off.

To create a level playing field we'd probably need to specify a minimum weight.
As I fly electric, I vote not to change the rule.

Jim O

vbortone

My Feedback: (2)

So do I. I have two models "Abbra". One is electric and the other one is glow with YS 160. Both meet the current rule. I don't think that make sense to change it.

Regards,

Vicente "Vince" Bortone

f3a05

But it also means,that a YS 160 plane takes off at a weight something like a pound above the 5Kg limit.
And some would say that the resulting higher wing loading suits the current models/schedules/flying styles/judging fashions/prejudices, better, especially in wind....

Just a thought.

OhD

That is the discussion I was trying to generate. Yesterday I was talking to a guy (YS 1.60 pilot) who had finished behind four electrics at the weekend contest and was frustrated because, as he said, the electrics flew so slow and smooth. He was considering an electric for the first time.

I believe the lighter airplane allows a greater speed range and my experience says weight is the enemy of flight, especially in pattern planes. I must admit I haven't a lot of recent contest experience in high winds but it would appear the new electric setups can fly as fast as the glow.

We'll have to observe the results from the big competitions this summer to decide if the heavier wing loading is better. In the mean time I guess we are just speculating.

Jim O

f3a05

That is undisputed---but a narrower speed range can be easier to control---and the nearer a model can be flown to a constant speed,through most of the schedule manouevres,the easier it is to attain geometrical accuracy.
Have a look at the CPLR F07 at the recent Europeans for a good example.
Just my opinion.

shannah

My Feedback: (5)

Having just started flying pattern again, after a few years off, I'm not sure my opinion counts for much. But I think some weight allowance should be made for electrics. If 1 lb is deemed too much, then make it slightly less (perhaps .25Kg). But, only let the electrics use the increased weight to compensate for the dry weight of the IC ships, IC ships still have to make the 5Kg dry weight. I think the desire for extra weight allowance boils down to the need for more power and duration. They used to handle power disparity by giving the 4 stroke engines a displacement allowance. Eventually that went away with the lifting of displacement requirement. Now, electrics get penalized by the method of determining weight and they are penalized by the 42v limit. Those are similar to displacement limits for IC engines. So, to be fair, there should be some allowance granted to electrics so they don't fall behind. If all were equal, you would see more of a balance at the world championships. This year, I don't think you'll see too many of the very top tier flying electric because it doesn't have the power advantage. I can't imagine a plane like QQ's new bipe making weight with an electric power setup. If it did, it wouldn't have the power necessary to match the 1.70. So, since there is an advantage to IC, then the penalties for electrics should be reviewed. Weight is the easiest thing to attack in order to keep parity.

Bponder

I am in favor of a Rule change to No weight limit ! sounds crazy but my reasoning is this, Most every glow plane that takes off in competion loaded with fuel is Well Over the 5kg weight limit. The electrics are under the 5kg weight ready to fly "With Fuel". Myself Flying electric I would like the advantage that the glow guys have of being able to carry that extra weight of "glow Fuel" 18 oz on those windy days. If you can fit it in a two meter box and fly it competetively with too high of a wing loading or too low of a wing loading more power to you. But I believe that the Two meter Rule will serve as its own weight governing mechanism

BW

f3a05

I don't have a vote, but if I did, I'd have:
Model must fit inside a 2X 2 M square.
Model must weigh less than 5Kg, less fuel.
Fuel would be defined as liquid in tank(s) if glow or petrol.
Batteries powering motor if electric,with no restriction on number of cells.Hopefully,this last thing would encourage development of higher-revving electric set-ups to catch up with the current glow motors.

OhD

You don't need more voltage to rev higher. Just get a higher Kv motor and put on a smaller diameter prop. As Kv goes up Kt goes down so you won't get the same torque for a given current. Thus a smaller prop. I haven't gone through the numbers but I believe you could duplicate the performance of the YS 1.60 with a 10s setup.
My thought was that I don't want something as good as a glow engine, I want something better. Perhaps at the top level glow is better but electrics look better in my neighborhood.

Jim O

Super D

I'm with ya BW, I basically tried to post the same thing to the NSCRA list. I think it was filtered.

If your 2X2 and wanna weigh 20 lbs have fun, your long downlines will be fun to watch. The only possibility I see bad out it is a plethera of bipes that would proceed.
Dylan

f3a05

quote]Thus a smaller prop. I haven't gone through the numbers but I believe you could duplicate the performance of the YS 1.60 with a 10s setup.[/quote]
My understanding of leccys wouldn't cover the pointed end of a pin, unfortunately,but I've seen and flown a few contemporary set-ups.
I.E. Abbra/Hacker/14wind/22x12/21x13
Integral/Hacker/14/22x12
Both of these have adequate power for the current schedules,with the ability to give a reasonable,but not outstanding, constant speed.
But they're both too slow overall for British weather(IMO)--read windy!
Those long props make the rudder work better for the integrated rolling manouevres though!---but that canaliser thingy does the same at less expense!
Last year there was an Axi/older Matt design(?Smaragd?Lazulite) flying the comps here---and although quicker,the pilot looked uncomfortable with the power delivery---very rapid acceleration on both up- and down lines.

So, is there an electric set-up that could do(say) 8200 rpm on (say) a 17x12, or 18x11,and would that get near the YS??

OhD

It is hard to say without some propeller data. It is sad that we don't know how much power it takes to drive a given prop at a given rpm. I have one progam that says it takes 4.5 HP to swing an 18x11 at 8200 rpm and 3.9 HP for the 17x12. This same program says it takes 4.3 HP to swing the 22x12 at 6000 rpm and I know that is not true at least for an electric prop. I suspect it might be true for those 22x12 clubs we put on gas engines but it is not true for my electric prop. I don't have any better values.

I guess I will need to dig out an old 17x12 and see what kind of power it takes to turn it. If it is somewhere near 3.5 HP I believe the electic can do it for short bursts. If you need to fly full throttle for the whole flight it won't.

Jim O

Chris Moon

My Feedback: (8)

I agree with Jim that no changes needed. People can make weight today with electrics and to give them any additional leeway is not necessary. At 11lbs, an electric already has an advantage as far as flying weight and wing loading. What I like about pattern is that we can take a rule and find a way to meet it using technology and innovation. That has been the history of pattern flyers as far as meeting low noise standards or meeting 11lbs with today's large but light weight planes. Quiet tuned pipes, high pitch propellers, lightweight composite structures, electrics, etc. etc. I fly electrics and love it and won't ask for special treatment.

f3a05

But,is it an advantage?
The leccy takes off at around 11 lbs.
The glow might be near that weight dry, and averages at least 1/2 lb more during the flight,and, on a windy day,given the power available nowadays, that can be a distinct advantage,IMO.

Chris Moon

My Feedback: (8)

I don't think that's an advantage to be heavier. If it was, you can just put a 40oz tank in the plane and use it as ballast legally. The higher wing loading and lower performance from the higher weight is surely a disadvantage. Lighter flies better although I do agree that you can get too light but I don't think any of our modern 2 meter planes come close to being too light.

flywilly

My Feedback: (121)

I'd like to see the 2m x 2m restriction eliminated. I think it has constrained design development as everybody wants to build to the 'rules'; so all the airplanes are 2meters long with slight variation on wing span/size. Perhaps a smaller design would be more effective...? Or a larger one. Power is unlimited. I'd love to see somebody win the worlds with a simple model like Prettner did with his Calypso in 1983 (is that a dream or a fantasy?).
Electrics seem like the ideal solution to many current (no pun intended) pattern issues especially throttle linearity. Power failures seem less likely, but still possible and there's much less mess to clean up (unless you have a fire... my personal fear[:'(])
Glow power appears to have an edge when it gets windy and I suspect the 2007 FAI F3A World Champion will be glow powered.
My 2 cents...
-Will B

f3a05

Well, not a 40 0z tank, but a certain (very) top European has ballasted his model to close to 5Kg dry when it's windy.

jamesjoneill

I think that the size restriction should most definitely not be removed. Bigger planes fly better, that is an indisputed fact - unfortunately bigger planes also cost more, so those that could afford the bigger planes would have a distinct advantage over those that couldn't.

Our current 2m planes are amazing to fly, way better than the older, smaller planes built around the 60 size two strokes, but that doesn't necessarily make for a better competition. For a good competition you need a level playing field, and many would argue that going to 2m has already pushed some people out of F3a - or restricted what they can do because of the increased cost. To allow any sized model would be a very damaging step.

You won't see anyone win an F3a competition with a calypso any more, but you will almost certainly see someone win with a simple model. Sure, they may be advanced, refined designs (so was the calypso in its day), but our models now are probably about as simple as they have ever been. Fixed u/c rules now over retracts for instance, and our planes are about as simple as a model plane can be. They have an engine (of some sort) and a wing and a few servos. Doesn't make them any less awesome to fly...

Regarding the weight issue, well it is probably too early to tell. The current rules were introduced when it became apparent that a 20cc four stroke gave you a major power advantage over a 10cc two stroke, and the rules were not fair - there was not a level playing field. The difference between the current i/c and electric models is probably not as big as that was, so it will take longer for the subtle advanges of one over the other to become apparent. While there is no obvious advantage to one over the other, why change the rules? If most if not all i/c and electric models can be built within the weight limit of 5kg, why change it?

And, if you electric boys want some extra ballast on a windy day, is there actually anything to stop you putting a fuel tank in your plane and filling it with a pound of coolpower 30 before flying? Just a thought... ;-)

James

patternflyer1

My Feedback: (11)

I also fly Electric. I do feel the glow has the advantage on windy days. Out here in our district, most of us have propped to speed up our planes quite a bit. Especially on windy days.
Here's an idea that I've thrown around for awhile. If we want to carry the same takeoff weight, we "CAN" put a fuel tank in our electrics and add as much fuel as we like.

I feel my Abbra is too light on windy days. 10lb 1 ou. With such a big fuse, I need more weight to penetrate like the glow planes. My Evolution with the same setup but at 10lb 15 ou penetrates much better.

I think a no weight limit should be in order anyway. What's the difference what it weighs? As long as it fits in the 2m box..
I feel, if you want to fly a brick, fly a brick. Or vice versa if you want to fly a feather, fly a feather.

I think this weight limit may hurt alot of businesses that can't get their planes in lighter for electric. Therefore alot of people don't purchase their product. There's quite a few planes out there, and several won't make weight easily with an electric setup.

But, I will abide by whatever they say. I will just chose wisely when buying an airframe.

My .02 cents.

Chris

Malcolm B

From what I saw at the TC in Ireland Alan a good electric probably has more power and as much speed as a 160 set up - and that was in windy conditions. I've only seen two really good lekkies in the UK (Steve Burgess and Malc Harris) and all the rest have quite frankly been pants which Keith Jackson confirmed. Basically get a hold of an Irishmen, any Irishmen who flys lekky (alternatively Steve or Malcolm), copy his set up and you'll be good to go.

Interestingly Niall O'Sullivan was using an APC 20X15 cut down to an 18.5" diameter. Simply superb. Motor was Plettenberg, batteries were I think Flight Power. The power Niall had was simply unreal with great forward speed.

can773

My Feedback: (1)

Actually we asked Skinner about the fuel tank thing a while back, doing that to an electric model would not be allowed as the fuel and tank is not a fuel source in an electric.

can773

My Feedback: (1)

Malcolm,

What pletty was that? 30-10Evo? I have been meaning to try something like that but no time!

Angus Balfour

I think it was a 30-10 Evo Chad. Very impressive.

Pattern_is_Fun

An interesting conversation... it's been shown that electrics can make the current 11lb limit w/o much effort.. provided you have a composite plane ($$). Try and find (in general) a $500 or less airframe and see if it comes in under 11lb if converted to electric. Not very likely. I know my old Poetic would have a problem meeting the 11lb limit. This was a great entry level 2M pattern plane for electric conversion in my opinion. We need more models like this that will allow others to make the move to electric if they want, yet not cost them a pretty penny for the airframe. My conclusion; increasing the weight limit would allow more pilots to make the transition to electric at a more reasonable cost.

Speed of electrics.. There seems to be rumors around about who will be flying what (gas / electric) at the Nats and the World's. "Brazil will be windy" is the general consensus.. and flying electric will not be to your advantage there. Maybe. So the Top 5 pilots in the World may fly gas.. so what? Many electric flyers are changing to higher Kv/volt motors which provides for faster speeds if you want it. Get an airframe, and this is critical, that will allow for faster flight, head toward a 20.5x14 prop with a Kv/Volt similar to a Hacker 13XL, and you will be able to fly as fast as you want at UNDER 3000ma/flight (FAI P/F 07). This is a great setup. Even if you don't agree (but you should - ;-)) take a look around at your next contest and see who's having motor problems and dead-sticks. It's not the electric guys. Sacrifice a little (a little) speed for reliability, you're ahead of the game.

Conclusions: Increase the weight limit for electrics so more pattern pilots can make weight with less expensive planes and electrics can fly fast enough in 90% of any pattern competition, if set up properly.

sc

can773

My Feedback: (1)

Hi Scott

So what if Argentina is windy I say France was windy as hell also (during the prelims), and Roland and Wolfgang were flying 15xl's on 22x12's (not the fastest setup), in fact most guys were flying setups that are slower than today.....CPLR and Onda were flying YS 170's (same as they will be flying this year) and the electrics did just fine. My setup was way slower than I have today and I had my best finish in the Worlds ever.

Forget the power plant.....its all in the fingers