guys was wondering if the Extras are more tricky and less forgiving then the Edge 540 when it comes to 3D flying? and if so then what could be the reasons.....wondering if the sweep back wind design in extra could be the reason.PLS help!

here is a secret
there are no real differnces in any of this 3D stuff. except for weight and power relationships..
Any of em.
All the advertising you see - bullsmanship

but the question remains....an extra with the same wing load and power to weight ratio as an edge 540 will have an equal ease of manouverability or not.im sure the aerodynamics due to different wing shapes will have some role to play in manouverability of both the planes.whats ur take on this?

I'm sure that the different wing shapes play a large role in performance and aerodynamics. I am a firm believer that there is as much variation between Extras of two different manufacturers as there is between and Extra and an Edge from the same mfg. However, I have flown Extras and Edges and have felt a difference that has been pretty distinctive. It's kind of like Cubs. They don't all fly the same, but they all kind of fly like Cubs (if you've had one, you'll know what I mean). You might hate me for this, but I don't believe either model is better or worse than the other....they're simply different. They each have their strengths and weaknesses and niches within the realm of 3D flight.

Sorry if that's not the clear-cut "one is better" answer I'm sure you were looking for, but that's my opinion and you're going to know it anyway .

well boyz- The early Extra and the EDGE are really about the same design
and you can cogitate the sweep factors till the cows come home
But
th lightest one with the most power will be the best
ther isn't 2 cents worth of difference otherwise.
Size really doe not matter eithe
Having done the 33% series of H9- aerobats- the lightest ones were the best
but I liked the CAP and the EDGE I had because I had the power jacked up in these. (not the weight -the power .) Going down . We redesigned all the flying surface on one EXTRA - thinner n lighter sections -it was same planform but the reduced weights really showed upto IKARUS models -we again saw the same thing in5-6- ounce flyingweights .
40% stuf? again -the same - the light one
27% ?same again
The corker is in full scale aerobatic types
same thing
th best performers have highest power -lowest relative weight

hmmm....reasonably clearified on this now...thanks a bunch.

Dick, it seem like people are being conditioned to accept overweight models as the norm these days. A lot of the 40 sized ARF's are now in the 24-28 oz/sq ft range. If only my town had manhole covers.

Dick,
I think you missed this one.

They each have their own tendencies and yes wing shape / location. Stab shape / location. Engine shape / location all have something to do with how well it 3D's. Weight can override some of these factors but not all. When is the last time you saw a trainer doing axial rolling harriors???

If you want the airplane to fly exactly the same upright as inverted then the wing and stab should be in the same reference plane. That way the downwash in either upright or inverted flight is the same and the downwash is a strong contributor to the horizontal tail effectiveness. Having the inline wing and tail condition will cause all maneuvers will be more symmetrical with the same control inputs. Having the wing in a horizontal axis through the center of mass of the airplane will help keep the rolls axial, etc. For example the CAP has the low wing and high stab which makes it pretty bad compared to the other two airplanes mentioned.

That being said if you lay the planforms over each other you'll probably find them all to be very close to each other - close enough to the point that indeed power to weight becomes the predominate factor. Well sorta - you also need a light wing loading to go with it. Putting a hugh heavy motor in the front of a small light airplane won't make it fly OK. A look over the airplanes that are being used at places like XFC indicate what are good setups to use.

Having a good pilot will help a less than capable airplane but a good pilot given the choice will pick the best airplane to win the XFC (try to remove the effects of sponsored pilots, etc.)

I personally don't care for the CAP but I have seen it flown beautifully by a lot of people. I should admit I had a very heavy CAP that would try to snap roll whenever I gave it too much elevator throw. I gave it away.....

Ben

I guess I look at results not some idealized concept
FWIW one of the best axial rolling designs I ever flew /seen is the ZLIN526AFS
very low wing setup with some dihedral
for those who don't know the axial roll centers on the spinner and thd stab to give the optical illusion of a pure axial roll The wing location is of secondary importance.
The CAP232 is one of the , if not the best show designs going because the force setup provides for great end over end tumbles
All of em will tumble- the CAP just has the best setup for it.
Will a trainer do axial rolls ?
You bet yer asp it will - if set up right
A clipped wing Monocoupe will do the entire bag o tricks.
I can do horizon to horizon slow rolls with any wing location and the model looks to be right on "line " the spinner /cowl is your visual reference.
Now for the Doubting Thomases:
take a stick held pattern model -oneof theose little planes used to work out sequences on the ground and readjust the stick such that rolling the model either aligns the spinner or misalignes it , as you twirl the stick
It takes a litle futzing but soon you will see the alignment of the fuselage which gives an apparant perfect axial roll
(why do I do this ).

Dick the airplane is a set of inertias, a cg location all driven by a set of aerodynamic parameters. For a roll to look good to us you want it to roll with the fuselage not varying in pitch as it rolls. You can do a lot of things during that time with aero inputs to keep the fuselage straight.

Or you can design an airplane that doesn't need the inputs. Take the modern FAI pattern airplane design. They have everything inline - thrust line, wing, horizontal tail, No dihedral, etc. it makes things simply easier.

The Clipped Wing Monocoupe won't do a roll in a straight line because the aero forces are undergoing a large change as it rolls the full 360 degrees. For example that configuration will have a different roll stability upright compared to inverted. For a constant aileron deflection that means the roll rate will vary during the maneuver. The roll coupling due to inertia will cause a change in sideslip angle which also feeds into the roll rate and pitch angles. If you are going to try to slow the roll then through the inverted part you need some inverted lift "up". To get that requires a large angle change because of the flat bottomed airfoil. That makes another input into the roll asymmetry. And so on.

Our eyes aren't a good instrument to measure things like this. Also if you tell me it's going to be an axial roll, I like everyone else is probably going to believe you and the halo factor will come into play.

On the F-15 project we tested the machine pretty throughly. It can look like it was doing a perfect roll but when you looked at the instrumentation it really didn't. We weren't surprised since we had wind tested and computer simulated the machine beforehand. It lines up things pretty nicely but there is enough asymmetry in the airplane as in the Monocoupe that it doesn't roll straight.

But the thing is that the physics of the maneuver means that some airplanes will roll better than others. Again I point to the FAI designs. They do roll on a line.

Why don't large scale models use the setup? Simply, there are no full scale models that look that way so if you want to fly in any large scale contest you have to fly the other machines. If there were they would be flown in the XFC.

Back to the CAP and downwash angles. Right, it will tumble and I have seen one knife edge right off the grass forever it seemed, but for a given elevator deflection - up or down - the resulting diameter of the loop will be different due to the difference in elevator effectiveness due to the change in downwash angle at the tail through the loop.

On the F-15 project we tested the machine pretty throughly. It could look like it was doing a perfect roll but when you looked at the instrumentation it really didn't. We weren't surprised since we had wind tested and computer simulated the machine beforehand. It lines up things pretty nicely but there is enough asymmetry in the airplane as in the Monocoupe that it doesn't roll straight.

Ben

deja vu?

Ben, did your office have escalators?

I guess we are playing a word game - To me -from years of judging pattern flying pattern-an axial roll is one which appears axial- You F15 was "axial " per some instrument evaluation. along a zero pitch line(?) The Monocoupe will roll axially (appear axial)
At least a model of it will and layout for models is what I was referring to.
As for pattern moddels All in a line setup ?
Not for me! I have way too much experience with pattern setups to do that
I designfora wee bit of stability , which makes everything look more locked in.
3D foam flip flop stuff ? another ball game -
you can get away with murder simply because the wing loading is often 2-3-4 oz per sq ft.
CAPS :I have done a bunch of em starting in 1984. are all very light and inside /outside maneuvers feel the same or so close to it , I never feel any extra correction is needed .
The one in the photo above was a fairly stock H9 33% . look at the flying angle . The model was flying at that angle My super light 27% was even more agile . It was Scratch built and weighed 13 lbs
My point is that the full scale comparisons mean zip when looking at model aerobats
the wing loading ( for example your snappy Cap) means everything BUT once you get a handle on that . the rest ofit is of little concern.
Note your little VAPOR. It does what it does due to extremely low loadings
I love that little model.
how would one inprove it using full scale practices?
I have tried a lot of different layouts looking for advantages in various layouts sizes n weights wing placement on n on.
(see attached examples)
All of the stuff shown does (did) axial rolls the pilot makes the difference in how well the roll looks but again, an on line model is not required .

Nice to see you back posting Ben. We don't often get celebrity photographers here :-).
All full scale McAircraft people welcome.

Quote
Back to the CAP and downwash angles. Right, it will tumble and I have seen one knife edge right off the grass forever it seemed, but for a given elevator deflection - up or down - the resulting diameter of the loop will be different due to the difference in elevator effectiveness due to the change in downwash angle at the tail through the loop.
Quote

As a CAP lover (and ex-Pattern guy) you are on and off the throttle and elevator so much that it all works out to be nice and round. Kind of instinctive.
BTW my best CAP would easily out fly my best "purebred" (looks like all the others) Pattern ship in any sequence.
Pattern always has been a 'follow the leader' design exercise as you also know.

The 'one elevator position a loop does make' applied only to reeds. And I know you remember that as well.

Dick,
You sure do have some pictures, don't ya?
Looks like those full scale guys aren't too far behind
[link=http://www.airshowbuzz.com/videos/view.php?v=ae99b37d]Video[/link]

All of em are planes I designed and made with the exception of the EDGE which is a H9 design I reworked
After the first thousand , it gets easy -

I have always been totally jealous of Dick's many airplanes. It's not fair that he didn't send them to me when he was through with them. It is true that with lower wing loadings that the downwash effects on the horizontal tail become less pronounced. To me the ideal airplane is one that doesn't require all of the small corrections that the good pilots give them. The CAP can make identical inside and outside loops for example but if we measured the actual elevator deflection to do them it would be different. It just proves what a good machine the human eye/brain setup is.

I do believe that the perfect airplanes aerodynamically are the big FAI ships although I have never understood the little T that one of them has just behind the canopy area. All he needed to do was make the vertical tail just a smidgeon bigger. I guess once the mold is made he didn't want to change it. But with the FAI ships you don't get any inertial coupling effects during any of the maneuvers which keeps things awfully nice for the pilot - he has a lot less to do to keep them pointed straight. Otherwise we would see CAPs and the like being flown in FAI pattern.

Now Dick, do you really want me to believe you designed the airplanes - or - perhaps you designed the structure inside of the exterior shape? All you have done is put a skeleton inside of a great looking shape......

One last comment about the Vapor which Dick and I do agree on. It is challenging enough to keep your interest up. Some day we'll have a full house aerobat that will be nice in a living room but until then the Vapor is great. Pylon races would be great with 3 or 5 in a large living room. When I was in High School I kept trying to get a single channel airplane to work with a ground based transmitter so when I was presented with the science in the Vapor I was amazed. Something that weighs just 15 grams that flies under perfect control surely must get any die hard modelers heart to beating just a little.

Ben

Almost there!!!!
[link=http://www.rcvideohub.com/play.php?vid=317]Video[/link]

build thread is under "this is just too cool" on another site, where they fly giants...

Except for th H9 33%model -all of the others I did from scratch and in some cases made the plugs -The no scale ones were totally mine
The Buckers were TOC models for 1992 (?)
Inever used scale airfoils on the scale model - they were always counterproductive in my book. The Buckers tho were exact scale except the wings were clipped 9%- the airfoils were colse copies of retrofitted sym panels made in Switzerland in 1960s.
Today I spent the afternnoon helping a friend stuf a ZDZ210 into a 3.3 Yak 55. Glad it ain't mine as it just fits in his extended wheelbase Chev van
The plane should be a terrific 3D setup at upward of 50 pounds!

Those little "T"s are perfect examples of that competition and the competitors. There is a chance the originator added it for show and it's affect on the judges. The contest there is more presentation than precision nowadays. Anything that impresses the judges works.

Most of our models that're based on full scale have more design in them than the uninitiated would ever expect. And it's not just the structural decisions that make them fly well as models. Dick isn't the first or last to use an existing full scale as the basis of an aerobatic model. But I'd bet big money that he, like almost all the rest of us who design models for model performance events and chose full scale, didn't lose a moments sleep over changing any measurement on the suckers. I daresay there probably isn't one model in a hundred that's designed for aerobatics that's based on a fullscale that has more than one or two measurements to scale. And all the others are fudged on purpose. And the purpose is to suit what the designer wants out of the model.

Agreed on the little T thing - can't you just imagine the other guys wondering if they needed one. Vortex generation can do nice things at times, but if it was supposed to work on the vertical tail in high sideslip maneuvers I think the vortex would miss the tail. Maybe it works to keep the tail from wobbling in yaw in straight and level flight...

Speaking of presentation - a friend in the local club is really heavy into pattern. He practices it many times a day and doesn't fly anything else unless it's to test fly someone's airplane. He is very good. But the position/distance out from the flight line of the pattern is so far that an observer gets really uninterested in a hurry. That is the reason I like the XFC type of contest. They are big fire breathing airplanes flown close enough to appreciate them. They aren't unsafe or flown in such a manner that someone would get hurt and I don't have to get out the telephoto lens to see them!

The pattern today is a series of lines far away with some knots in them now and then when the airplane snaps. Boring.

I wish I lived next door to Dick. He has too much fun for a mere mortal person and the amount I could learn would be a lot. I couldn't afford the models I wanted in the numbers I wanted so I have only built a couple bigger than a .60 sized model. But I do enjoy the big airplanes flying in the hands of a good pilot. They are a joy and easy to photograph too.

As far as designing a model, most designers lay out something based on their experience and what others have done. They fly the airplanes and they fly OK. But to quantify what the changes actually did, whether it hurt a little or helped a little is difficult to prove. It would be nice if someone had the cash to rent a low speed wind tunnel and run some experiments. I nave no doubt the tests would back up a lot of what we take as common truths but it might be very interesting in a lot of cases like airfoils chosen, moments, tail locations and so on.

There hasn't been any real new model design in pattern in several years. It's like looking a new cars, you can't tell what it is until you see the nameplate. Not like in the 50's and 60's. Then I could tell cars and pattern airplanes from several hundred feet away. As far as large scale aerobatic models go, if we lay the planforms over each other there isn't much difference. The biggest difference is the location of the horizontal tail of the CAP and that has been proven to not be a tremendous handicap in large scale aerobatics. I would think the big Yak's, etc. would be better though.

Aerodynamics and model design is an interesting topic....

Ben

Like the T tail thingy (I thot it was a TV antenna!) on the pattern planks, the vertical location of the horizontal tailplane is -in my book- highly over analyzed.
As is much of the solemn advice of changing angles of incidence - (usually in degrees ) fancy that -
Do any of these guys realize that ONE degree is almost 1/4"in one foot??
A full scale craft such as the Dalotel may have the inclined at say 2-3 degrees - BUT that does not mean that the wing flies at 2.3 degrees AOA.
When we designed (dare I sayt hat?) a pair of Zlin Z 50's for the TOC in 1976(?) for D Brown- I elected to put both the wing and stab at the same angles (0 decalage) BUT they were also tipped down relative to the original setup
This made the fuselage fly a little lower at the rear.
May have been a waste of time but the models flew well..

I had to chuckle, TV antenna is great!

I'll let you say "designed" with the setup on the Datotel. Your choice of the angles did change the fuselage angle and does indeed change the inertial coupling that come with it in a roll and other maneuvers. It may not be much but in a game of good airplanes and pilot,s all the edge you can get helps. Too bad Dave was getting old by then and had lost it :-)

Does Dave ever read these things? The last time I saw him was at last year's XFC and I challenged him to a drag race, my three wheel scooter against his four wheel machine. We are both falling apart - like an old rusty car going down the road and dropping off a part now and then - I won't discuss what comes out of the exhaust system....

I remember when Hanno P. won with a Datoel, but then he won with a lot of different airplanes. I wish I could have seen him fly. I have a Curare in my hangar. It is an interesting good flying airplane.

Ben

I saw Hanno fly at various TOC- his concept of the "right plane"
was vastly superior to th US stuff- yet NONE of the guys even tried his approach.
His Dalotel (s) was really fudged but had super low wing loading
I used the French presentation drawingsfor my models of it those plus writings from Mssrs Dalotel and pics.
The plane really flew as well as anything else on the market but the pattern boys hated anything scale
(could NOT be any good)
The EXTRA with less than 10% deviance- same thing -not apattern model
Here is One Jim Villwock did - Jim races Unlimited Hydros too. The Partner is a late type pattern plane - this one by afriend's son in England