rm

My Feedback: (27)

You go to a pattern contest, they're gonna say you should consider a pattern plane. You go to an IMAC contest they're gonna tell you you'll need a bigger plane. That's the nature of the sport. As far as someone saying they won't even try it because they need a high dollar plane to compete is just an excuse for someone who's really not that interested.

neilga

I have a trimming question that I hope Bryan can answer. I have read and used your "triangulation trimming" pretty successfully, including running the CG of my pattern plane at 25%. But I would like to know the current trend of where to leave the elevator trim.

I used to fly pattern years ago, and it was always recommended that the elevator trim be set symmetrical, so that it went nose down if the controls were left untouched the same amount inverted as upright. Then your plane would (if you had the incidence right) climb straight up hands free, and dive straight down hands free. But now with fixed gear and positive wing incidence it seems that people are trimming for almost hands off inverted, allowing the plane to fall a bit inverted. Is this correct?. This makes a big difference to all the other trims for vertical climb and dive.

Thanks
Neil

neilga

sorry - typo in my post. I meant to say that people are apparently trimming for hands off upright, and the planes falls nose down inverted.
Neil

Freddy

My Feedback: (3)

6 kg?.......no!
If we open that up the race for more power will continue.
5 kg + 1% tolerance we have now is perfect.
One really does not need more power than a YS170DZ.
Just keep challenging the manufacturers on how to get power out of smaller packages (glow, gas, electrical).
That is in line with current eco friendly green thinking and every bit helps save our planet.
Thank you FAI for keeping the sanity in F3A one of the best and longest standing rules ever written in Model Aviation.

highfly3D

I simply dont understand why people what to extend the weight limit.... this is really madness to me. For people who want to change n modifiy rules can better go fly in IMAC competitions.

klhoard

My Feedback: (10)

.
Any many do just that . . . .
.

Angus Balfour

So do you think IC and electric models are treated equally within the existing rules? Personally I think it would be a more even playing field if all models were weighed before take off and each had to be under weight "X". Allowing IC planes to be weighed without fuel yet stipulating under the same set of rules that electric planes must be weighed with batteries is unfair and bias against electric.

serious power

Hi Angus,
I wonder how would everybody feel about the idea of 5Kg +or- 1% ,including fuel and or propulsion batteries.
It would seem like a good way to have a level playing pitch and the FAI 5Kg limit.

Brian

[/quote]
[quote]ORIGINAL: Angus Balfour
So do you think IC and electric models are treated equally within the existing rules? Personally I think it would be a more even playing field if all models were weighed before take off and each had to be under weight ''X''. Allowing IC planes to be weighed without fuel yet stipulating under the same set of rules that electric planes must be weighed with batteries is unfair and bias against electric.

bjr_93tz

Maybe, but IC planes have always been weighed with the batteries in. I ask why should an electric plane be exempt from this?

Just because it's for the motor and not the radio gear is a hollow argument under the current rules.

However, given it's the 21st century and we are bound to see further innovation, it sort of makes sense to dispense with the fuel/batteries in/out debate and push for a unified maximum takeoff weight. Consider placing rules limiting propellor total blade area, diameter, pitch (or all three) should take care of any HP wars no matter the power source.

Anthony-RCU

My Feedback: (2)

+1

Angus Balfour

Hi B,

I do see where you are coming from, but it would immediately render a lot, perhaps even all IC planes illegal which is not what we want to do. I actually think 5.5kg RTC (ready to compete ) is a great idea.


I don't see it as a hollow argument at all and I'm actually not saying electric should be exempt. I'm saying weigh them both ready to fly.

Exactly

No need for those extra rules, we already have the noise limit which automatically limits how much power we can use.

serious power

Angus,
Would it really ??
Surely all that would be needed is some lighter/smaller engines ,exhausts and batteries.
This would have to be cheaper also.

BTW I'm not for a moment suggesting such a change - I'm just wondering how people really feel about the holy grail of 5Kg and cost. Ie while having a specification for what actually flies, as opposed to a spec,, with exceptions/qualifications - weigh with a,b & c if ?? but without x,y and/or z if ??.

Brian

[quote]ORIGINAL: Angus Balfour

'Hi B,

I do see where you are coming from, but it would immediately render a lot, perhaps even all IC planes illegal which is not what we want to do.

serious power

Hi,
Here is what is actually proposed for the upcoming plenary meeting ;

MTK

RCU, geesh!

MTK

RCU

MTK

This is incomplete.....Any propeller must turn to do any work. Prop size doesn't matter if the prop isn't being turned...

If you meant it as total work being done at maximum power by the propulsion system, perhaps! That takes into consideration not just the power system but also the load being carried.Personally I think it would be too cumbersome to go down this path. It's possible, but improbable...

I think the E guys have areasonable argument regarding theirrecylable/renewablefuel source(bateries). Consider a YS powered model weighed without its fuel. Well, as has been argued countless times before. 20-24 ozs of 25% glow fuel (sg=0.9) weighs over 1 pound and as of right now, that weight is gratis (consumed in flight so it currently don't count.....!?! insert argument here!)

grantb

I am a fully E-guy. I have flown electric pattern since I started in 2006. I support the change to a uniform measurement.

All that said, nobody has mentioned the huge weight disadvantage of Nitro 2x2's when it comes to designing for the stresses of being beaten to death by a cake mixer mounted to the nose of the plane. I, personally, don't find the current weight restrictions a problem and having more pilots sitting on 5500g within the current size limitations is an advantage (to me, anyway!!) Who knows, tri-planes are only a season or two away

Maybe, together with the relaxation in weight, one can lose the 1% tolerance, which I suspect is going to become an issue soon.

drac1

My Feedback: (4)

The need for more power came when manufacturers started designing bigger aircraft. If you look back to the Oxai Pinnacle for example, the 160 DZ struggled to haul it around in all but good flying conditions.
This then necessitated the requirement for more powerful engines.

Maybe the physical size of the planes need to be limited somehow. Not the 2x2 rule, but fusealage size??

bjr_93tz

Of course it's incomplete, it's just tossing an idea out there.

However if for a (very) rough example it was decided to limit 2 blade props to 22" diameter, 3-blade to 21" and 4-blade to (including contras and twins) to 20" with a minimum aspect ratio, then it would effectively cap any HP war by virtue of the noise limit.

You can only put so much power into the prop no matter the source, the total energy expended throughout the flight is still the pilot's option whether it comes from methanol, batteries or petrol.

Or they can just leave the rules alone and people can simply follow them instead of trying to change the ones they don't like.....

apereira

The limits being 2x2 or 5000grs have been driving the technology, no one would guess we could have what we have these days back when Hanno made the proposal, batteries are getting lighter because of the 5000gr on F3A batt types same with motors, look at the weight vs power nowadays, and the YS are getting more displacement too on the same weight, increasing the limits will not change anything but it will render the high end equipment useless as the manufacturers will take advantage to it, and this very same argument will repeat itself again in the future.

cmoulder

In the not-too-distant future glow pilots will be complaining that the electric guys have an advantage because of light batteries. Already, some of the lightest e-power models weigh around 4500g.

It would be interesting to see "A Brief History of LiPo Technology" to document the progress in battery development over the past 8-10 years.

neilga

When you have a max weight including the fuel, the guy whose plane is on the heavy side will be forced to fly with a small amount of fuel, possibly causing a flame-out. So in that way it is easier for the weight rule to specify empty tanks.

When I last flew with a glo motor I used the OS140. It could do a pattern on only 10 ounces of fuel. This is 300ml, and weighs about 260grams. Does a YS170 use much more than that? So 5500g total allows glo planes to increase their weight by maybe 200g, and electric planes by 500g. I think this would be a big relief to everyone. There would be less need for using tiny receiver batteries, or ultra light carbon props, etc

Neil

drac1

My Feedback: (4)

My Valiants running YS175cdi's, are using around 210ml per flight.

ANGELITA

My Feedback: (7)

I think that if the weight rises to 6 kilograms it will be but accessible and cheap for all and not alone possible for those who have but money.

Mario

cmoulder

With all due respect, what is more likely is that the new weight limit will quickly be exploited to create more advanced airframes and power systems, which will both cost much more. And everybody will feel they need the best stuff in order to be competitive, much as it is seen now by many with the current rules.

As it stands now, airframe and power system designs have reached a certain stasis that has allowed advances within the 2x2/5kg box to trickle down to much more affordable models.

One could argue that it has never been cheaper to acquire an extremely competitive Pattern ship.