But..., Mithandir, do you fly IMAC? or not?

We tried to get him to a couple yrs back.......no luck.

I like the plane checking at the TAS idea. Maybe just those who make the final cut instead of only the winners.

My two bits. I also agree with Judge, Wayne, Tank, and Bogan on the scale definition. A +/- 10 percent of wingspan is a pretty generous variation. That can be thought of as a 20 percent range. Although, perhaps Rule 6.5 does need further explanation. Wingspan defines the scale. By the rule "fuselage width, height, and aircraft planform or any other variations shall not exceed 10% of scale". So, can the wing planform change at all once the wingspan, or "scale", is set? It sounds like the wing planform is pretty much set, since the wingspan is the basis of scale. The variations are in the size (dimensions) and position of the fuselage, stabs, elevators, fin, and rudder. I am also not sure about the vertical variation in position of the engine, wings, and stabs. I thought that a mid-wing Extra 300 could not be used until one was used in full scale, and that is why modelers went back to the 260 for a while, in order to get a more neutral coupled design.

Also, IMAC is by definition International "Miniature" Aerobatic Club and is considered "Scale" Aerobatics by AMA. That is, our competition is based on the premise that we are to fly "scale aerobatic" planes. In other words, any plane flown in Sportsman Class and above must be a scale version of a full scale plane that has flown in an IAC event. The Slick 360, Slick 540, Sbach 300, and Sbach 342 are more recent and popular introductions to the definition, as is the Yak 55. So, if our planes don't look like the full scale versions, we are not following the premise of "Scale" Aerobatics. That's one of the reasons I like IMAC, is the scale factor. We are emulating full scale aerobatis, even to the Aresti elements that are flown in IAC and the way they are judged. Our scale R/C planes are like the full scale, but they are what we can afford, and we are not risking our life and limb by being in it. Although, we aren't feeling the exhilaration of all the G forces and world rotating around us. In a more youthful time I would have loved to do the full scale aerobatics. Just can't do that now. So I stick with IMAC.

By the way, have any of you watched www.airsports.tv ? There's some great full scale and R/C vids there.

Originally Posted by Mithrandir

"LAZY"

sheesh... wtf do you know?

I know you don't want to deal with flying a scale plane in scale aerobatics.

Originally Posted by wingwall

So, can the wing planform change at all once the wingspan, or "scale", is set?

Chord and thickness can change, wingspan cannot. Once you you you have changed the percent scale of the plane.

Also, IMAC is by definition International "Miniature" Aerobatic Club and is considered "Scale" Aerobatics by AMA. That is, our competition is based on the premise that we are to fly "scale aerobatic" planes. In other words, any plane flown in Sportsman Class and above must be a scale version of a full scale plane that has flown in an IAC event.

Almost most, but not quite right. Here is the rule:

3. Open Events:
3.1: The events accommodate aerobatic monoplanes and biplanes which are replicas of types known to have competed in International Aerobatic Club (IAC) competition, or replicas of types known to be capable of aerobatic competition within the airspace know as the ―Box.‖

So it does not have to have been actually flown. It just has to be capable of flying within the IAC box.

So, if our planes don't look like the full scale versions, we are not following the premise of "Scale" Aerobatics.

As long as the plane meets the rules then it is legal. Why twist that up needlessly?

Read the actual objective in the rules:

1. Objective: To duplicate full-scale aerobatics with miniature radio controlled aircraft in a realistic manner that is challenging for the contestants as well as interesting for the spectators.

Notice it does not say anything about "scale".

Again, from the book:

6.3: The general outlines of the model shall approximate the full size outlines of the subject aircraft. Exact scale is not required. The model shall be judged for likeness at a distance of approximately 10 feet.

Interesting discussion to me as myself and few friends are in the process of drawing plans for a scratch built 44% Extra 260, WS 130, Lenght 122 w/spinner . We took into account the 10% rule but only as it pertains to wingspan to length, I guess will need to take into account the side dimensions as well. Anyone have a 3 view that shows all the those dimensions?

How do the current crop of common kits airplanes do in the 10% rule? Carden, Dalton, Aerotech etc?

Originally Posted by dbrford

Interesting discussion to me as myself and few friends are in the process of drawing plans for a scratch built 44% Extra 260, WS 130, Lenght 122 w/spinner . We took into account the 10% rule but only as it pertains to wingspan to length, I guess will need to take into account the side dimensions as well. Anyone have a 3 view that shows all the those dimensions?

How do the current crop of common kits airplanes do in the 10% rule? Carden, Dalton, Aerotech etc?

I can't speak for the others... but I know FOR SURE that ALL the STOCK Dalton airplanes are well within 10%.

I can present docuemntation to anyone that would like to challenge.

MattyMatt

Was not trying to single out Dalton on that question....as a matter of fact, I will be ordering an ML from Tony next week.

Originally Posted by dbrford

MattyMatt

Was not trying to single out Dalton on that question....as a matter of fact, I will be ordering an ML from Tony next week.

No worries man... just giving facts! Happy Turkey Day!

I know that Dalton, Extreme Flight and Carden are well within 10%. I have measured myself.

I just happen to know quite a bit about the Daltons! Congrats... you'll love your new ML300.

Originally Posted by wingwall

But..., Mithandir, do you fly IMAC? or not?

not yet

I was gonna try once... but the CD told me my plane wasn't scale enuff...

Hope all had a great Thanksgiving.

Sorry Judge with any mis-interpretation or mis-understanding. I believe we are in general agreement. I was just trying to state that we, that is IMAC, are, by definition and rules, a competition group that flies planes that are scale versions of the full scale aircraft, and if we were to change to allow any and all kinds of aerobatic aircraft, as others might want, it would not be "scale aerobatics".

On your first point I didn't quite understand what you were saying, but I believe we are in agreement that the chord and thickness can change. I was referring to the "planform", such as, within the +/- 10% rule, can the proportions be changed, for example, such that a wing on an Extra has a straight in-line leading edge as that of the wing of an Edge? I believe that could be done with the +/- 10% rule. The straight in-line leading edge of an Edge 540 is a common characteristic of that plane. Most people will use that very characteristic to identify an Edge. Whereas, what I have found common with Extras, is that the leading edge is typically perpendicular to the tapered sides of the fuselage. (I don't know why that is, or if it is just for convenience for building to get the design close to what the taper is intended to do.) It appears that a Slick is somewhere in between for some reason.

You got me with the second point (3.1). Although, I would hate to be a CD to make that call. Who and how does one decide what is "known to be capable of aerobatic competition"? Perhaps there should be an official list of what is "known".

As for the third point (or third Quote), I do believe my statement is in line with Rule 6.3. I do not know for sure, but I believe 6.3 was written to take care of the first point, above. An Extra should look like an Extra, and an Edge should look like an Edge. I believe it was an attempt to take care of the finer points the +/- 10% rule could take away from an aircraft.

On your fourth point, (Objective I believe you have taken something out of context, and are arguing a fine point. The scale definition portion is in another part of the rules, specifically in 6.5. Although, someone could also argue that a "duplicate of full-scale aerobatics with miniature radio-controlled aircraft" is a strong indication that scale is intended, since "miniature" by definition is small-scale.

I don't think this went vary far to answer Jason's question, or did it? I believe the rules are fairly well written and allow a pretty wide range of likeness to the full scale. I think defining the percent of scale by the wingspan is appropriate, and after all other adjustments within the +/-10% rule, it should look substantially like the full scale. I also like the definition others had about using the largest overall 3D dimensions, height, width, and length, and proportioning from there. I assume an origin for all of this should probably be the CG of the main wing.

I'm still waiting on wing and stab placement.

Originally Posted by wingwall

On your first point I didn't quite understand what you were saying, but I believe we are in agreement that the chord and thickness can change. I was referring to the "planform", such as, within the +/- 10% rule, can the proportions be changed, for example, such that a wing on an Extra has a straight in-line leading edge as that of the wing of an Edge? I believe that could be done with the +/- 10% rule.

According to the rules you could for instance make the root chord 10% wider and narrow the tip chord by 10% and still be legal. But once the scale is set you cannot change the span of the wing. Everything else can very by 10% of the scale measurement.
i

You got me with the second point (3.1). Although, I would hate to be a CD to make that call. Who and how does one decide what is "known to be capable of aerobatic competition"? Perhaps there should be an official list of what is "known".

There is no list now nor has there ever been one that I am aware of. As stated in the rules ultimately it is up to the pilot to make the case for the plane. The CD makes the determination based on the evidence presented by the pilot. If no evidence is presented then it is still the CD's call.

An Extra should look like an Extra, and an Edge should look like an Edge. I believe it was an attempt to take care of the finer points the +/- 10% rule could take away from an aircraft.

Agreed. The appearance is the final determining factor. There is a bit of a contradiction in the rules because if you took the +/- 10% to the limits you could produce a legal plane based on measurements that does not look very much like a full size plane.

I like the way someone else put it. They called it the "duck rule". You know, if it looks like a duck, quacks like a duck then it is probably a duck.

This comes back around to one of my favorite discussions and that is the pilot panel rule. The main argument is that without a pilot and panel that we are not really flying scale planes. Which of course we are not really doing in the first place.

For instance, when was the last time you saw a full size Extra or Edge where the elevators were more than 50% of the chord?

Originally Posted by Mithrandir

not yet

I was gonna try once... but the CD told me my plane wasn't scale enuff...

Mith......That is because you were trying to compete in intermediate with a H9 Mustang PTS trainer.

1. Its not 10% scale of a mustang
2. Mustangs can't perform the IAC sequence in the "box"

Originally Posted by sweetpea

Mith......That is because you were trying to compete in intermediate with a H9 Mustang PTS trainer.

1. Its not 10% scale of a mustang
2. Mustangs can't perform the IAC sequence in the "box"

Kermit Weeks flew a P-51 as a demo at a World Aerobatics Championship. I cannot recall the year. He flew his Freestyle routine as I recall.

Keep in mind that the rule does not say what sequence or what needs to be flown. Only that the aircraft is known to be capable of doing so. Any number of warbirds could qualify based on that criteria.