I may have to ask you to explain this one. I have never wished an airplane heavier but can recall a multitude of times I wished an airplane to be lighter.

An object in motion stays in motion unless acted upon by another force. The lighter the object the smaller the force necessary to affect change in direction. Conversely, the heavier the object the larger the force necessary to affect the same change in direction. What force? Wind.

Yea, there is a point of diminishing return - unless you ask a Mercedes Benz engineer about their Golden Era race cars.

NOt only good questions but good answers!!!!!!!!!!!!!!!! I can see speed has never read the thread on the CG Extra and saw the normal weights for one of the best flying 60 size planes ever made. Worth the read isn't it!!

I have never seen a CG Extra powered with a .60. I had one with an OS 108 and power was good but it suffered from typical conditions of an overweight airplane. Snaps were sluggish and difficult to stop. Rolls on the vertical ( point rolls and snap rolls ) were difficult as the airplane lost speed quickly. At that time the airplane weighed 8.5 lbs. The 1/4 scale Lanier Laser I had after the GC Extra weighed 7.25 LBS and was powered by the same engine. Performed much better. Not sure how much I buy into the wind effecting a heavier airplane less as when in flight the airplane only sees airspeed and terminal velocity at any power setting remains the same. We see it differently because we are set firmly on the ground and it's the ground speed that we see. I tend to change props ( less dia. more pitch ) when I fly IMAC in windy conditions so that I can fly upwind at a higher airspeed as to make the airplane APPEAR to fly constant speed regaurdless of wind .

As far as wind causing the airplane to change heading, its usually turbulant wind that can be somewhat avoided by flying higher. Some airplanes do what I call wind dampen better then others.

Ilike your term "wind dampening" - very descriptive. Ifly at 6000 feet - air density kinda limited. Control surfaces really lack bite. We are constantly affected by wind gusts - being that our field is just barely on the west side of the front range. Direction is all over the place during a 10 minute flight - 180 degrees is not unusual. Not being an expert flier I tend to rely on experiences from sailing small boats and motorcycle road racing. Both are very sensitive to small wind changes.

I'm learning with a big grin on my face that at our altitude what other people call a 60 size airplane well call a 90 size or bigger.

There's many vehicles that I'd love to operate at sea level - you lucky dog!

I have built several Great Planes Ultra Sports.

It calls for a sheeted LE and cap strips on the back of the ribs.

I have built them fully sheeted, Sheeted on top with cap strips on the bottom, and once I built a "Lite" version where I went through all sorts of things to make it light, like cutting lightening holes everywhere, building up the stab and fin instead of using the supplied sheeted pieces, etc.

The "Lite" version flew well, but it was nowhere near as good as the heavy ones.

Read the thread. Most the CG Extras are powered with 1.20 four strokes and come in between 11 to 13+ pounds. Your also the first person I have heard say it was sluggish in anything. I have never seen anyone try to power the plane with a .60 either. Back in the days before 40% planes the CG Extra was one of the planes of choice for IMAC flying so it must do something correctly even if it is a heavy weight. I have also never heard anyone try to compare A stinger to an Extra. As much as I like the stinger I prefer the Hots. Sort of an apples and oranges thing.

Please keep in mind that the OP's question is in regeard to the GP extra, not the CG Extra

Two very different animals

Please read more carefully. I was comparing an Extra 300 to a Laser that weighed more than a pound less with very simular wing planforms and areas. The Laser was the forunner of most of todays aerobatic aircraft. The Extra 230 was built as direct competition for the laser and the 260 and finally the 300 followed. Not really apples and oranges.


Minn has a point, we do seem to be getting off the subject somewhat. I am keeping an open mind here but so far I have not seen any explainations to how in any circumstances a higher wing loading benifits a current aerobatic design.

I believe the opinion was that a lighter version was nowhere as good as a heavier one. That makes sense if you consider the possibility the heaver wasn't heavy, that ultimate vertical probably wasn't in the flight schedule, and gusts and turbulence affects would cause more problems with a lighter version.

Higher wing loading really is relative. So is "lighter". I've built two Extras in the last season and flew the heck out of both. The first was a pound lighter than the second. When the second was new, I didn't like the way it compared. It could easily do everything the first did except where "vertical" came into the picture. Both could do the schedule I fly, and do it with ease. But the new Extra slowed more over the tops etc. I swapped the OS61 for an OS75 about a month ago in the second Extra. Right now, when I have to choose between the two, there really is no contest. I like the way the heavier plane flies better than the lighter one. As it is, the heavier plane is nowhere close to being a heavy airplane. And if I were to build a third from scratch, there wouldn't be a seconds hesitation to sheeting the wing. In my experience it can easily be done without adding significant weight, and the model in question has plenty of leeway for a few more ounces. Would I sheet it in plywood? nope, and I wouldn't do a foam/sheeted wing either.

I think that's actually spot on the topic here, btw.

Rock, that was a great answer. You reminded me that " Heavy " is suggestive. Being an R/C pilot of 33 years I do tend to expect the world out of my airplanes. In order to fly some of the IMAC advanced and unlimited sequences you need to have a rather high power to weight ratio. IMAC seems to think that throwing lots of rolling elements both point rolls and snap rolls on vertical uplines is a good thing. this consumes huge amounts of power. For me it has always been easier to reduce airplane weight to boost power to weight. As far as a heavier airplane being less affected by wind, I have found that wind will affect a well trimmed much less then a poorly trimmed airplane regardless of weight.



As far as the OP I was and am concerned that he will put all the effort into building an airplane that will suffer from too much weight to even be a good sport flier. Granted adding wing sheeting may have only added a couple OZ but then he started weighing engines and stating " 1/2 pound is nothing to me" leads me to beleive that in the end he may just end up with a 10 lb airplane and be dissapointed in it's performance. Trust me I have seen this happen dozens of times. One good example of this is when I had built a Midwest 202. Mine was powered with a Webra 120 and weighed 10 lbs even. On its maiden day a fellow club member came up and complimented me on the clean build but the proceded to tell me how horrible the airplane flew. He told me not to slow it down too much as it had tip stall issues, it wouldn't knife edge, took way too much down elevator for inverted flight. After questioning him I found his was powered with a Moki 180. He beefed up the motor box, welded his own stainless tank, used all metal geared servos, wanted to fly all day so put in a 2400 MAH nicad battery. In his mind each item was "only" a couple of OZ but in the end he was left with a 14 lb airplane and was unhappy with the way it flew. Eventually he bought mine.

You're right. It is absolutely important to keep weight in mind. For example, even if I were to build a fully sheeted wing from scratch, I'd use Hitec HS225 servos in the wings to run the ailerons. After all, they save you about an ounce each compared to lots of the standard servos.

Everything should be considered all the way down the line. Beginners do need to hear about that "everything", because there are lots of them. They also need to get a perspective on the values of each, what the choices cost, and what they get you.