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Building Tips and technical articles. => Building techniques => Topic started by: RC Storick on October 21, 2013, 12:38:00 PM

Title: My MC 72
Post by: RC Storick on October 21, 2013, 12:38:00 PM
What I did was find a picture on the web shown below.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=135715;image)

Then I took it into Photoshop and scaled it up 150% so that from the back of the spinner to the end of the rudder was 41 inches long. I saved it as a PDF and took it to Kinko's to have copies made. Laid them on the bench and they are in eyeball perfect form for a stunt-er .

The wing plan form is constent cord and for ease of math its 10 inch root 44 inches long. It will have a six inch radius tip for a total. So a 6 inch radius circle has 113 squares and a 2 inch flap 44 inches long has 88 with 440 squares in the wing. Total them up and we have 661 minus whatever the fuse takes up so I figure around 640-650 squares.

2.25 spinner and a 10.5 nose with 16.5 tail. The battery will stand straight up in front of the wing and split tether line. The motor 2826/12 AXI is above tether so the ESC and timer will rest below that line. Fuse at leading edge will be 3 inches wide and top and bottoms will be molded.

We shall see what a box of wood and a idea yield's.

Title: Re: My MC 72
Post by: Duke.Johnson on October 21, 2013, 01:16:12 PM
Robert
I love the plane! Can't wait to see what you come up with.  Will this be another fast pace project?
Title: Re: My MC 72
Post by: RC Storick on October 21, 2013, 01:23:23 PM
60 days seeing as I am working again.
Title: Re: My MC 72
Post by: Duke.Johnson on October 21, 2013, 01:42:52 PM
I'll be watching for progress pictures!
Title: Re: My MC 72
Post by: RC Storick on October 21, 2013, 02:30:37 PM
First days progress 10/21-2013.

Laid out and stab and rudder cut and sanded. I will get my fuse wood tomorrow and I will have that laid up by Friday. I might do the rough tip layout today as well.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=135717;image)

I do not normally work from drawings this large but I wanted scale and I also needed to balance out the CONCENTRAITED Mass.
Title: Re: My MC 72
Post by: MarcusCordeiro on October 21, 2013, 03:31:32 PM
 ;D 8) 8) 8)

Marcus
Title: Re: My MC 72
Post by: Steve Helmick on October 21, 2013, 05:44:48 PM
Good to hear that you're employed again!  y1 Steve
Title: Re: My MC 72
Post by: Avaiojet on October 21, 2013, 06:58:21 PM
Robert,

Nice project.

Built up tail feathers?

Charles
Title: Re: My MC 72
Post by: wwwarbird on October 21, 2013, 11:09:25 PM

 Cool. y1
Title: Re: My MC 72
Post by: Peter Germann on October 22, 2013, 04:59:22 AM
Here's my version, built in 2006/7 after a trip to the museum of the Italian Airforce in Bracciano, Italy:

OS.72 4-cycle
1'900 Grams or 67 oz
1.57 m (62in wingspan)
Nice flyer, but not the ultimate competition machine. Donated to and on display at the Swiss Transport Museum in Lucerne, Switzerland.

For details,go to: http://www.aeronautica.difesa.it/MuseoVdv/Pagine/default.aspx

rgds, Peter Germann
Title: Re: My MC 72
Post by: M Spencer on October 22, 2013, 08:05:51 AM
ditto .
 :## S?P
(http://www.clstunt.com/htdocs/dc/user_files/20307.jpg)

(http://www.clstunt.com/htdocs/dc/user_files/20240.jpg)

http://www.youtube.com/watch?v=scX1erFyxeE
real live very one .

made a fatter pair of floats for mine , for appearances sake . or in case theres waves .
have to testem yet . With the skinny ones it flys like its on rails .No adverse affects .
Unless its blowwing , then it weaves in gusts with the forward area forward .
Title: Re: My MC 72
Post by: Tom Niebuhr on October 22, 2013, 09:52:29 AM
Robert,
Will you have wheel pants on this one?
Title: Re: My MC 72
Post by: M Spencer on October 22, 2013, 10:02:06 AM
(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_Castoldi_72_13.jpg)

 %^@

(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_MC72_foto_24.jpg)

http://www.modelbrouwers.nl/phpBB3/viewtopic.php?f=183&t=36813

(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_MC72_foto_01.jpg)

Should be a few of them in he bottom of that lake still somewhere , if anyones got a snorkle & flippers .

Title: Re: My MC 72
Post by: RC Storick on October 22, 2013, 10:23:12 AM
Robert,
Will you have wheel pants on this one?

Yes big ones This design was chosen because of the fuse area behind the CG. I am standing the battery straight up in front of the LE so the tail has to be extremely light in order to balance. My rendition will be very scale like. All except for wing location and moments. Size of the stab and elevator has been increased. Also no floats. This was the airplane that Tucker designed off of. Worked then so it should work now.
Title: Re: My MC 72
Post by: RC Storick on October 22, 2013, 10:39:45 AM
Great site thanks I can make it more scale like now. Im going to use Al Rabe tricks for detail.

(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_Castoldi_72_13.jpg)

 %^@

(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_MC72_foto_24.jpg)

http://www.modelbrouwers.nl/phpBB3/viewtopic.php?f=183&t=36813

(http://www.modelbrouwers.nl/albums/coppermine/albums/userpics/10378/Macchi_MC72_foto_01.jpg)

Should be a few of them in he bottom of that lake still somewhere , if anyones got a snorkle & flippers .


Title: Re: My MC 72
Post by: Brett Buck on October 22, 2013, 08:20:33 PM
What I did was find a picture on the web shown below.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=135715;image)

Then I took it into Photoshop and scaled it up 150% so that from the back of the spinner to the end of the rudder was 41 inches long. I saved it as a PDF and took it to Kinko's to have copies made. Laid them on the bench and they are in eyeball perfect form for a stunt-er .

The wing plan form is constent cord and for ease of math its 10 inch root 44 inches long. It will have a six inch radius tip for a total. So a 6 inch radius circle has 133 squares and a 2 inch flap 44 inches long has 88 with 440 squares in the wing. Total them up and we have 661 minus whatever the fuse takes up so I figure around 640-650 squares.

2.25 spinner and a 10.5 nose with 16.5 tail. The battery will stand straight up in front of the wing and split tether line. The motor 2826/12 AXI is above tether so the ESC and timer will rest below that line. Fuse at leading edge will be 3 inches wide and top and bottoms will be molded.


   Looks like a good prototype. Are you going to move the wing up, or put in dihedral?  And what is the "tether line"?

    Brett
Title: Re: My MC 72
Post by: Steve Helmick on October 22, 2013, 09:51:27 PM
And I gotta ask, why is the registration number "N 12366"? I thought "N" was for USA (for some reason I don't understand either) use only? I know "C" is for Canada, and would think "I" would be for Italia, etc. Whazzup with that?  ??? Steve 
Title: Re: My MC 72
Post by: wwwarbird on October 22, 2013, 10:32:48 PM
 Brett,

 Check out the above photo showing Sparky's line drawing of the models fuselage. It shows where the wing will be, up from the scale location and more toward the models center or thrust line. I'm guessing the "tether line" is Sparkyspeak for the estimated leadout position in relation to the vertical CG. Homing in on the vertical CG is of course one of the main reasons for moving the wing up, to find a happy "tether line" for the model.

 Steve,

 12366 is Sparky's AMA number. Many modelers add the N in front of their number. It just gives a full scale feeling and sometimes, like in this case, adds to the cool factor.

 Sparky,

 You should trace patterns as you build this one, in case someone wants to think about kitting this thing.
y1
Title: Re: My MC 72
Post by: RC Storick on October 23, 2013, 09:48:06 AM
  Looks like a good prototype. Are you going to move the wing up, or put in dihedral?  And what is the "tether line"?

    Brett

Tether line is the exact center of the bell crank location. Mass but be evenly distributed above and below that line. It does matter! Ask Yatsinko. Of coarse I could follow the other lead and design this plane with the 10 ounce battery in the belly. Heck it might be a world beater then.


Title: Re: My MC 72
Post by: RC Storick on October 26, 2013, 09:05:43 AM
teth·er  (tr)
n.
1.
a.  A rope, chain, or similar restraint for holding an animal in place, allowing a short radius in which it can move about.

b.  A similar ropelike restraint used as a safety measure, especially for young children and astronauts.

2.  A rope, chain, or similar restraint for holding one, especially an animal, in place, allowing a short radius in which one can move about.

3. The extent or limit of one's resources, abilities, or endurance: drought-stricken farmers at the end of their tether.

tr.v. teth·ered, teth·er·ing, teth·ers
To fasten or restrict with or as if with a tether.


No mater what any one says point of tether is not at the wing tip. Its at bellcrank pivot. Some with higher learning and math skills may dazzle you with some equation or theory but from extensive building and testing I know it does matter and many others do as well.

If your bell crank is located above or below the center line of the wing tether line will fall there as well and you will need to adjust the mass accordingly to that line and not the center line of the wing. Centrifugal force will try to make all these thing line up. This is a point most forget. Flying in a circle is far different and more complex than one thinks there are no pi times radius square formulas that apply.
Title: Re: My MC 72
Post by: RandySmith on October 26, 2013, 11:32:19 AM
 "No mater what any one says point of tether is not at the wing tip. Its at bellcrank pivot. Some with higher learning and math skills may dazzle you with some equation or theory but from extensive building and testing I know it does matter and many others do as well.

If your bell crank is located above or below the center line of the wing tether line will fall there as well and you will need to adjust the mass accordingly to that line and not the center line of the wing. Centrifugal force will try to make all these thing line up. This is a point most forget. Flying in a circle is far different and more complex than one thinks there are no pi times radius square formulas that apply. "

What is incredibly important is that the Lead out position on the tip be in the correct place, not too high or low for the plane's CG , if it is too high or low the plane will roll in or out depending on location. This will drive many crazy trying to make the plane fly right !The LO has to be in line with the verticle CG.
Addressing the Bellcrank location, "if" you put it too far forward, backwards, up, or down, you can run into bad problems with drag...  and excessive lead out wear, in my mind, I am with Sparky in putting it as close to the CG as possible, matter of fact what I do is put the BC on the exact spot that I think the CG will be, then move it 3/8 inch forward, this helps with drag and wear.

Randy
Title: Re: My MC 72
Post by: Howard Rush on October 26, 2013, 12:14:30 PM
Just do an experiment and you'll see.  Holy cow.  This is so basic.  Control line flying isn't some alternate universe that levels the playing field between those who paid attention in high school and those who didn't. 
Title: Re: My MC 72
Post by: Serge_Krauss on October 26, 2013, 02:40:03 PM
Flying in a circle is far different and more complex than one thinks there are no pi times radius square formulas that apply.

Any variance can make a simple thing more complex to analyze, but flying in a circle of itself is simple and there are simple equations that do apply. However, this particular analysis depends simply on Newton's basic laws of motion. Randy and Howard are quite correct. This is extremely elementary. While it is advantageous to place the bellcrank near and slightly ahead of the c.g., as Randy says, so that the leadouts exit the wing tip without having to bend and rub to accomodate aerodynamic line rake, the thing can be placed anywhere. All that is necessary is for the wings to be held level and fuselage tangent to the circle by coordinating c.g. location and line positioning at the tip, which then falls along the radius from the handle to the c.g. Then any misalignment will cause unbalanced forces via the lines at the wing tip that Newton's first two laws dictate will restore the wing to alignment (edited to fix dumb wording). Building a simple hanging model made from popsicle sticks, pins, and string will verify this, and the same analysis goes for up-down as fore-aft bellcrank positions. It is not and never has been "rocket science."

Mathematics (not needed in this argument), is simply a way of allowing us to use common sense without confusing ourselves. If that is not understood, then feel-good myths about math deficiencies will continue to abound to the detriment and confusion of all. Math is not "formulas". Formulas are short-hand ways of remembering and expressing relationships that are known from measurement, observation, and logical reasoning - nothing more. Again, they're not relevant here - unless one needs to prove what can already be reasoned out.

SK
Title: Re: My MC 72
Post by: RC Storick on October 26, 2013, 11:28:41 PM
I guess everyone would agree that the Sharks fly well. Read here http://discovery-aeromodels.com/en/yuriy-yatsenko-classic-f2b-model.html

Just do an experiment and you'll see.  Holy cow.  This is so basic.  Control line flying isn't some alternate universe that levels the playing field between those who paid attention in high school and those who didn't.  

You right Howard I heard you say lengthen the tail and to get it to turn better at the TT. Well it will because it will be tail heavy or take out some of that nose weight for the same effect. Magic

   simply use common sense

All that is necessary is for the wings to be held level and fuselage tangent to the circle by coordinating c.g. location and line positioning at the tip, which then falls along the radius from the handle to the c.g. Then any misalignment will cause unbalanced forces via the lines at the wing tip that Newton's first two laws dictate will restore the wing to alignment (edited to fix dumb wording). Building a simple hanging model made from popsicle sticks, pins, and string will verify this, and the same analysis goes for up-down as fore-aft bellcrank positions. It is not and never has been "rocket science."

All well and good but how do you simulate centrifugal force? Or that don't matter?
Title: Re: My MC 72
Post by: Steve Helmick on October 27, 2013, 12:55:52 AM
Oh, thanks for the link, Robert. I Googled for "Yatsinko" and found a tree stump grinding service in Connecticut and a Dermatologist with a website.   y1 Steve
Title: Re: My MC 72
Post by: wwwarbird on October 27, 2013, 01:44:44 AM
 It's Yatsenko, with an E.  D>K
Title: Re: My MC 72
Post by: Trostle on October 28, 2013, 12:14:42 AM
No mater what any one says point of tether is not at the wing tip. Its at bellcrank pivot. Some with higher learning and math skills may dazzle you with some equation or theory but from extensive building and testing I know it does matter and many others do as well.


Oh boy!!!  Here it goes again.  For those who want to drink the well water of ignorance, go ahead and disregard all that has been written and previously proved that the bellcrank can be located anywhere.  What is important is the leadout guides relative to the CG of the aircraft, understanding that the CG is at one location on the vertical and horizontal axis of the airplane.  Yes, it makes sense to position the bellcrank where it makes sense structurally to do so as well as to align the leadouts from their guide to bellcrank to minimize friction and wear of the guides and leadout wires.

I will quote Bill Netzeband who wrote in his Control Line Capers column in the October 1962 issue of American Modeler - "Next time a guy tells you to locate your CG forward of the BC or in front of the lead out, shun him.  He don't know the facts.  The CG comes first, all else is related to it."  The physics of behind what was written 51 years ago still apply today to our control line toys.

Keith
Title: Re: My MC 72
Post by: Howard Rush on October 28, 2013, 12:33:27 AM
The physics of behind what was written 51 years ago still apply today to our control line toys.

Or hundreds of years before that whenever people started making free-body diagrams.  Or somewhere in prehistory when the first guy did an experiment with a vine and some twigs.  You can do the same experiment today.  This arm waving is silly.  Just do the dad gum experiment.  Robert says he's done it. 
Title: Re: My MC 72
Post by: Lauri Malila on October 28, 2013, 05:11:12 AM
I read Yuriy's article (again) and found no mention about the vertical position of bellcrank. But we talked about it (and l.o. height) quite a bit the last time he was visiting me. Actually, the original Classic's with vertical engine had the l.o. guide lower than the wing c/l, only because vertical c.g. When he changed to horizontal engine, the leadouts went to the wing centerline. But bellcrank position was never moved. The good thing about Yuri's take-apart system is that the vertical position can be manipulated but reason for that would be mechanical, to acchieve symmetrical control impulses. L
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 08:00:42 AM
I am totally sick of this disregard for my findings. Mount it anywhere you want I don't give a crap! At least read what Yatsenko has to say. Oh I know you folks are too brilliant to take any ones advice so do it anyway you like.

Quote
Short history of the way to this model creating may be interesting for builders because we all know (who do not know, believe us), that it is impossible to calculate the model, the only way is to accumulate the experience from various models building, and step by step moving to the “gold middle”, to the model that can fly, as you feel, it must fly in your dream. In this way, the most important thing is not to go the wrong way or too far. I know a lot of talented people who spent a lot of time and efforts to the bright experiments. But it was so far from the “gold middle” that it was only loss of time, and the understanding of a long way from that point did not allow these people to finish the research works and to come to the good result. Be careful with the time.

Please read the title of this thread My MC 72 Not any ones else's So unless your going to build it your input is moot. When all else fails Bill Netzaban is pulled out like a magic bullet , Well I think I will follow Yatsenko's lead with as many nation and international wins his planes have.
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 08:08:58 AM
Here is a guy who has a clue.

1. To install all surfaces and the engine "zero" is possible, if you have absolute straight plane for assembling (the table with very straight surface). With simple tools it is possible to fix all model surfaces straight according to this base surface. You must control the surface and be sure that it is straight. Curved and twisted base plane will give the mistakes, that will act to the model flight.

Take notice that all his airplanes have 3 degrees motor offset


2. Symmetric airfoil,how to make this? According to the construction of your model, step by step it is need to keep the dimensions of the airfoil. From the first step, the accurate making of the ribs templates, to the quality of covering, when the soft cover between ribs have symmetric curve on up and down surfaces of the wing.
Important to install flaps and the elevators to the axis of the wing (stabilizer). If it fixed upper or down, you receive not symmetric airfoil. This model flight will be not logic.

3. Minimum moment around the wing axis it means, that it must be very light nose and the tail. For this, better to start the model building from the stabilizer. If your built stabilizer is heavy, better do not use it for the model building, better to write off it to fighting looses, and to the experience accumulation. Using this experience, build the next, the next, until you will receive the waiting result. According to the weight of the stabilizer, and the engine weight, you select the nose length. Important to make this correct. Because if you will be mistaken, the center of gravity will be not on the place, you will be compelled to trim it by the weight, putting to the nose or to the tail. It is bad both, because it increase the called moment.
It is obviously, that better to select the light engine, than heavy. With heavy engine the nose must be shorter, also the total model weight will be higher. Both things are not good for the model.
Short nose model have not correct balance of the nose and tail area of the fuselage. Like weather vane, the model tries to turn the nose against the wind. Sometimes it is danger for the stability of the lines tension.
For minimum moment and weight of "Classic" was find the method of production in mould. The advantage of this method is the economy of the weight of the finishing surface layer.
Tradition way is to cover the balsa by paper with farther painting by some layers of paint, with intermediary finishing of every layer (nice but heavy finishing). Or cover by Oracover or another special covering films (not nice).
Painting the mould and receiving the good surface ready, give the advantage of the control of the finish surface weight. I do not find the possibility to have so good outside view with so minimum weight. It is the main advantage of the moulded models.Plus very good stability geometry, got from the mould.
One more word about the moments. It is the gyroscopic moment of the propeller. The best if the prop have no weight. It is impossible, that is why the prop must have the minimum weight. I had tried many kind of props, it was found that the wooden is the best as most light. From heavy plastic props the model twist the trajectory in the air, change the wing position according to the lines line, especial with more sharp turnings. Heavier prop, more RPM -  more action.
To understand the force, that acts to the model, it is easy of you will try to turn the axis of rotating bicycle wheel, if you keep this axis in your hands. You will be impressed.

4. Easy moving of the control system is possible to make, if you control all moving elements according to this aim. Every element. Better to use the friction pairs metal - plastic (Nylon), it is not need the greasing, and have minimum coefficient of friction. Also it is very long life and light weight.
Better to have limited shaking in the control elements, than hard control system moving. Our model is aerobatic, control system must be absolute perfect. To fly with hard control system is the same, as to drive the car with hard control wheel, all trees are your's. The same as hard control system increase the gravity action to the model, its possibility to "meet" the land many times higher.
How to control? When the model  is on the land, and you move the handle, you must not feel any friction. It reaches by every friction control system  element trimming during the assembly.
The weight of the control system is very important too. Inertia of very fast moving push rods makes the action of the control system more slow. It is not pleasure feeling, when the model is late for the handle moving. The same about the flaps and elevator weight. Minimum weight- minimum inertia. Faster model reaction.

5. You feel needs to create the new model of your construction.
Usually not very experienced designer gets as the example the drawing of famous or good model, and tries to modify it by changing of some dimensions.
For example , you want to have more stability and maneuverable model, than the prototype. You propose correct, that it is possible to do, if to increase the distance between the wing and the stabilizer. You correct this dimension and build the model.
Even if you will make all details according to the showed in the notes weight, probably you will not receive the waiting result. Because you did not think about the balance of the model. In wide understanding.
Every good flying model is good balanced. If you move the stabilizer farther from the wing, you change not only the aerodynamic moment of it, but move its mass too. So, you must understand, that you move the center of gravity back. Yes, the maneuverable will be higher with this stabilizer position, plus back center of gravity. But you loose the stability, the model is more sensitive in horizontal flight.

You loose the model total balance.
What you do when you understand this? You move the center of gravity forward, put the weight to the nose. But model do not want to fly better, it makes valve after the sharp turning. What happen? The balance stay lost. The moment of the model around the wing axis is higher, because the nose and the tail are made heavier. Plus the model is heavier to the weight of nose load.
For example, you is more experienced designer, and you understand, that you must save the position of the center of gravity. You move the stabilizer back, but increase the nose length, compensate the tail moment. It is clever and logic decision. However, you can not receive the waiting result again. Because you have the same higher moment around the wing axis, as before, only better situation, that there is no extra weight in the nose.
So, you start to understand at last, that if you change the stabilizer position, and want to save the model balance, it is need to save the center of gravity together with the moment around the wing axis. For this it is need to find the possibility to make the stabilizer lighter, according to distance, that you move it.
Is this all, as you think? No. We forget about the balance between the flaps and the elevator. Flaps moment and the elevator moment acts to various directions. If you increase the moment of the elevator, the moment of the flaps is the same now. So, you increase the effect of stabilizer many times more, than you had think. It acts to the possibility of the model stability after the sharp corners. To return the balance back is possible , if to make the flaps area bigger. Or to increase the flaps turning against to the elevator turning.
O.K., we have changed the flaps area. Or its turning. Possible, it will be need to increase the engine power, because the model needs now more energy for sharp turning, do not loose the speed.
You change the engine to more powerful. As rule, it is heavier. Again we are before the question of the position of the center of gravity and the moment of the model. Together, we have the question of the model total weight. But heavier model needs larger wing area… And so on, and so on.
I show this look like not difficult example of the model modification for showing, that not so easy to design the new model even from the prototype drawing. This 5th rule is important together with the showed before 4 rules of successful model.
I have showed only the characteristics, that is most visible. But there are many another things, that I did not show here. It have action to the model flight too, and you must know this. Its action one to another is so complex… If you design the model, and think, that may be you will be so successful , that without any knowledge and the experience you will draw now the best model…
The possibility of this is the same, as if you shoot to the sky with closed eyes think, that you will get the small bird, that flies some where high in this sky.
Literature, communication with experienced people, experiments with models, step by step you will move to the understanding of the model flight and the design.If you feel the designer talent.
If no, better to build the famous model that you like. In the best condition, according to the rules of success.

Success

Yuriy Yatsenko

English sentence structure and syntax is hard to read through but with a open mind some will figure it out.
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 09:08:04 AM
here is where I am at today.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136163;image)

Tail wheel mounted in sub rudder eliminating at least 1/2 ounce of tail weight. All that's left is bottom mold, hollow nose block, assemble wing. The wing will be the easiest part. This was a easy project to bring to life.

All up weights. Stab and elevators 2.5 with hinges and horn. Fuse projected weight 6 ounces. Projected wing weight with out controls 6 ounces. It will be a close race to make 50-52 but I believe in the end worth the effort.
Title: Re: My MC 72
Post by: Duke.Johnson on October 28, 2013, 10:18:14 AM
It looks really nice! I wish I could build that well. I have a Yates Dragon I'd like to build but I don't think I could do it justice.
Title: Re: My MC 72
Post by: Howard Rush on October 28, 2013, 01:22:24 PM
Looks good, Robert. Knowing you, it will be painted and flying in a week.
Title: Re: My MC 72
Post by: MarcusCordeiro on October 28, 2013, 03:12:42 PM
Like the tailwheel style...
Nice build! 8) 8)

Marcus
Title: Re: My MC 72
Post by: Howard Rush on October 28, 2013, 05:50:36 PM
You right Howard I heard you say lengthen the tail and to get it to turn better at the TT. Well it will because it will be tail heavy or take out some of that nose weight for the same effect. Magic

   simply use common sense

I used common sense, and it told me (although it might not be prudent to do for other reasons) that lengthening the tail would increase negative pitching moment due to pitch rate and decrease rate of change of downwash with angle of attack.  Common sense also told me that I can calculate the effect of lengthening the tail on CG and fix it by summing first moments of mass around the CG.  Anybody who paid attention in high school physics has that common sense.  Neither you nor "Yatsinko" invented it. 

All well and good but how do you simulate centrifugal force? Or that don't matter?

You can use gravity to do that simulation.  Hang the plane by the leadouts.  This will tell you whether it's the bellcrank position or leadout guide position that determines at what angle the airplane hangs.  It will also tell you whether the leadout guide (or bellcrank, if that's how the experiment comes out) is in the right place relative to the vertical CG.  The part that hanging the plane by the leadouts doesn't tell you is the effect of drag on the lines.  When the leadouts (or bellcrank, if that's how the experiment comes out) are in the right place, the airplane will hang nose down.  You can get a quick estimate of how far behind the CG the leadout guide needs to be (I'm just assuming leadouts here, rather than bellcrank position) by plugging numbers into Bob Reeves's Line III calculator.
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 06:08:33 PM
I used common sense, and it told me (although it might not be prudent to do for other reasons) that lengthening the tail would increase negative pitching moment due to pitch rate and decrease rate of change of downwash with angle of attack.  Common sense also told me that I can calculate the effect of lengthening the tail on CG and fix it by summing first moments of mass around the CG.  Anybody who paid attention in high school physics has that common sense.  Neither you nor "Yatsinko" invented it. 

You can use gravity to do that simulation.  Hang the plane by the leadouts.  This will tell you whether it's the bellcrank position or leadout guide position that determines at what angle the airplane hangs.  It will also tell you whether the leadout guide (or bellcrank, if that's how the experiment comes out) is in the right place relative to the vertical CG.  The part that hanging the plane by the leadouts doesn't tell you is the effect of drag on the lines.  When the leadouts (or bellcrank, if that's how the experiment comes out) are in the right place, the airplane will hang nose down.  You can get a quick estimate of how far behind the CG the leadout guide needs to be (I'm just assuming leadouts here, rather than bellcrank position) by plugging numbers into Bob Reeves's Line III calculator.

If that's all you understand oh well.
Title: Re: My MC 72
Post by: Steve Helmick on October 28, 2013, 06:13:52 PM
It's Yatsenko, with an E.  D>K

Sparky changed it from his original spelling, apparently. I know how to spell "Yatsenko" with an 'e'. I was lead to believe that this was a tree service in Connecticut. It makes sense that a tree service would know the effects of tether points, fulcrums and C of G, in addition to a thorough understanding of chipper/shredders and chainsaws.

I read the copied/pasted article by Yuri Yatsenko. He understands that he can't calculate where the BC goes, only revise the location on successive versions of his design, even on a composite model aeroplane.  H^^ Steve

PS: Spell Check wanted me to change "Yatsenko" to "yardstick". Just goes to show that Spell Check isn't very smart and is not at all trustworthy...and certainly can't make up for apathy.  
Title: Re: My MC 72
Post by: Howard Rush on October 28, 2013, 07:57:24 PM
I was looking for a 3-blade backwards spinner.  Chris Cox sent me a note saying that Brodak makes a homeless spinner.  I told him I'd look for one on the freeway exit ramp.  Seems that Chris's spell checker objected to "holeless".
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 08:13:38 PM
I read the copied/pasted article by Yuri Yatsenko. He understands that he can't calculate where the BC goes, only revise the location on successive versions of his design, even on a composite model aeroplane.  H^^ Steve  

I bet he understands centrifugal force too as many others seem to forget it. I pasted the correct link so I did the work for everyone no need to do a search. Just click and go.

He sure understood making things longer and heavier is BAD.
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 08:24:38 PM
I can not ever seem to express my opinions with out flack. I do not give a damn if someone follows my findings. I throw them out for the sane people to evaluate for them self's. Then the magic bullet is always pulled Bill Netzaban's findings. That's great but its not for me. He also forgot centrifugal force and if you don't think its a factor for electrics move the battery into the highest or lowest part of the fuse and find out how much difference it really makes. We could always popcycle stick this to death with false results.

So if you are one of the doubters, keep shooting into the air blindfolded at those humming birds in hopes to maybe hit one.

Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 08:58:13 PM
Mold buck made and taped together to show shape.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136205;image)

The profile of this plane is exact scale.
Title: Re: My MC 72
Post by: wwwarbird on October 28, 2013, 09:12:37 PM
I can not ever seem to express my opinions with out flack. I do not give a damn if someone follows my findings.

 C'mon Sparky, if you "do not give a damn" like you always say, then why do you get so wound anytime someone doesn't wholeheartedly agree with you?

 Plane looks awesome, just build it how YOU like. Bottom line, that's all that really matters. y1
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 09:23:30 PM
When someone builds one airplane every five years one wonders how long he will have to live in order to have real life findings of gross weight, bell crank and moment changes. Also balancing of components in the aircraft. If everything in a book was correct why are the people of higher learning questioning them self's on their understanding gravity of all things? NOVA So this makes me puzzled in making the tail longer and adding more nose weight.

Seeing as I build five planes on average (for the last forty years) a year I might have a grip on what does what when moved as opposed to building one every five to ten years.
Title: Re: My MC 72
Post by: RC Storick on October 28, 2013, 09:24:58 PM
C'mon Sparky, if you "do not give a damn" like you always say, then why do you get so wound anytime someone doesn't wholeheartedly agree with you?

 Plane looks awesome, just build it how YOU like. Bottom line, that's all that really matters. y1

Because they try to type down to me.
Title: Re: My MC 72
Post by: wwwarbird on October 28, 2013, 10:07:36 PM
I do not give a damn if someone follows my findings.
Title: Re: My MC 72
Post by: Steve Helmick on October 28, 2013, 10:26:04 PM
Steve,

 12366 is Sparky's AMA number. Many modelers add the N in front of their number. It just gives a full scale feeling and sometimes, like in this case, adds to the cool factor.


Robert said that the photo was copied and saved as a .PDF file, nothing else, thus the question. Meanwhile, I'll look forward to seeing how close both the vertical and lateral CG's comes out.  Oops, Spell Check wants to change "CG's" to "cogs". Damnit!   H^^ Steve

 
Title: Re: My MC 72
Post by: Trostle on October 29, 2013, 01:02:35 AM

vertical and lateral CG's
 

Very Interesting

KT
Title: Re: My MC 72
Post by: M Spencer on October 29, 2013, 08:43:05 AM
" So if you are one of the doubters, keep shooting into the air blindfolded at those humming birds in hopes to maybe hit one. "

http://www.youtube.com/watch?gl=GB&v=lYKC-3Se6_M&hl=en-GB

 :P LL~ the ducks dont have much to worry about .  H^^
Title: Re: My MC 72
Post by: Tom Niebuhr on October 29, 2013, 10:26:50 AM
Duke Johnson said " I wish I could build that well. I have a Yates Dragon I'd like to build but I don't think I could do it justice."

My father used to say "If someone else can do it, I can too"

I have lived with that advise.

Don't sell yourself short. The best part of this forum is that so much knowledge is shared.
Title: Re: My MC 72
Post by: Duke.Johnson on October 29, 2013, 10:39:02 AM
Duke Johnson said " I wish I could build that well. I have a Yates Dragon I'd like to build but I don't think I could do it justice."

My father used to say "If someone else can do it, I can too"

I have lived with that advise.

Don't sell yourself short. The best part of this forum is that so much knowledge is shared.
Thanks, I think I'm going to build a built up fuse and finish the best I can this winter to get ready for the Dragon. Now back to Robert's cool plane after this short message. :)
Title: Re: My MC 72
Post by: Randy Powell on October 29, 2013, 11:10:53 AM
I certainly see most of Robert's logic. But like everything  else, you take logic and do experiments then decide if it is logic. If Robert has done his experiments and is happy, regardless of "the math", I say Rock On.
Title: Re: My MC 72
Post by: RC Storick on October 29, 2013, 09:25:38 PM
Robert said that the photo was copied and saved as a .PDF file, nothing else, thus the question. Meanwhile, I'll look forward to seeing how close both the vertical and lateral CG's comes out.  Oops, Spell Check wants to change "CG's" to "cogs". Damnit!   H^^ Steve

I should have been more clear. The small red photo was doctored in PS with my numbers. The full size plane was brought into Adobe and a PDF was made from the plans at 150% of original size. Then traced on to white paper and center lines and wing locations were drawn. As I said before this will be as close to scale as one could get for a full blown stunt plane. Even the spinner is the right size.

I choose this airframe because I thought it would fall close to scale.
Title: Re: My MC 72
Post by: RC Storick on October 29, 2013, 10:32:31 PM
If Robert has done his experiments and is happy, regardless of "the math", I say Rock On.

There is hope
Title: Re: My MC 72
Post by: wwwarbird on November 01, 2013, 06:45:18 PM

 Got that thing ready for primer yet? ;D
Title: Re: My MC 72
Post by: RC Storick on November 01, 2013, 08:33:32 PM
Starting the wing tonight
Title: Re: My MC 72
Post by: RC Storick on November 03, 2013, 01:11:56 PM
Here is 2 shots of the wing. I should put the airframe together this weekend
Title: Re: My MC 72
Post by: RC Storick on November 03, 2013, 05:11:46 PM
Wing weight 3.1 ounces. I might have to add ballast say 10 ounces.
Title: Re: My MC 72
Post by: Dan Bregar on November 03, 2013, 05:14:21 PM
You do good work Robert, and lots of it !!!  :)
Title: Re: My MC 72
Post by: Dan McEntee on November 03, 2013, 09:57:40 PM
  Why not a I-beamer this time? And what wing are you using, looks like lost foam method?
  Dan McEntee
Title: Re: My MC 72
Post by: wwwarbird on November 03, 2013, 10:18:38 PM

 Are those laser cut ribs?
Title: Re: My MC 72
Post by: RC Storick on November 03, 2013, 11:23:38 PM
Its my design lost foam wing and no they are hand cut ribs
Title: Re: My MC 72
Post by: john e. holliday on November 04, 2013, 08:57:30 AM
Sparky you are an artist beyond compare.
Title: Re: My MC 72
Post by: RC Storick on November 06, 2013, 05:32:04 PM
Forth set of wing tips. These are molded and built up.
Title: Re: My MC 72
Post by: Howard Rush on November 06, 2013, 06:01:28 PM
That's very cool.  I might have to try that on the new dog.  Oughta take me a couple of months.
Title: Re: My MC 72
Post by: RC Storick on November 06, 2013, 06:07:13 PM
That's very cool.  I might have to try that on the new dog.  Oughta take me a couple of months.

I have 30 hours in tips and still don't have one done yet. The first 2 sets were too heavy and the third set was not well thought out. So this one was re thought and I started on them this morning. Lots of work! But I want a super cool MC 72. More scale like than any I have seen.
Title: Re: My MC 72
Post by: RC Storick on November 06, 2013, 10:20:45 PM
almost
Title: Re: My MC 72
Post by: wwwarbird on November 06, 2013, 10:41:27 PM
 After studying the previous pic that shows the tip outline on the foam cradle, I was wondering how you were going to finish the wingtip outside of the last rib.

 Looks like this plan will work, and it gives you some meat to work with for the leadout slot opening. y1
Title: Re: My MC 72
Post by: MarcusCordeiro on November 07, 2013, 03:31:22 AM
As always, very nice Robert.

Marcus
Title: Re: My MC 72
Post by: Doug Moon on November 07, 2013, 07:16:39 AM
Can you show the mold you used for the skin of the rib?

That looks cool.

Title: Re: My MC 72
Post by: RC Storick on November 07, 2013, 07:28:03 AM
Can you show the mold you used for the skin of the rib?

That looks cool.

No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.
Title: Re: My MC 72
Post by: RC Storick on November 07, 2013, 08:57:41 AM
Well thie is how its going to look. So far 3 days into one tip. This is the best also the hardest thing I have ever done.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136732;image)
Title: Re: My MC 72
Post by: Duke.Johnson on November 07, 2013, 09:00:29 AM
It is looking great Robert.  You're inspiring me to refine my building skills.
Title: Re: My MC 72
Post by: RC Storick on November 07, 2013, 09:07:07 AM
Thanks I'm really getting my stride back.
Title: Re: My MC 72
Post by: Duke.Johnson on November 07, 2013, 09:12:04 AM
I go through phases, sometimes I hit it hard and sometimes I can't get going.  I've had the PT-19 on the kitchen table for a week and haven't touched it.  The repairs are made and all I need to do is cover it.
Title: Re: My MC 72
Post by: wwwarbird on November 07, 2013, 04:53:30 PM

 Probably a stupid question but I'm assuming you hollowed the tip block?
Title: Re: My MC 72
Post by: RC Storick on November 07, 2013, 08:29:02 PM
Yes it weighed 3 grams
Title: Re: My MC 72
Post by: Doug Moon on November 08, 2013, 01:27:21 PM
No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.

That explains it well.  I was wondering how you were gonna make the ribs. 

That is a cool idea on how to make those tips.

They look great.

Thanks for the info.
Title: Re: My MC 72
Post by: wwwarbird on November 08, 2013, 06:56:03 PM
No sorry. How it was done is I took a 6 inch section of the male plug. Cut it into a circle and sanded the tip shape into the foam. After I had 2 skins I sectioned it at the rib stations for the rib templates.

 And he says he's "just a mechanic". ;D :##
Title: Re: My MC 72
Post by: Randy Powell on November 09, 2013, 04:28:24 PM
Yea, I'm in one of those spots right now. Can't seem to get going again. And with a plane near completion that's unusual.
Title: Re: My MC 72
Post by: RC Storick on November 09, 2013, 06:57:56 PM
Wing progress. Weight of this wing is 5.6 ounces including weight box, lead out adjuster and tips. With un sanded  flaps its 7.25 no hinges or horns or BC.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136843;image)
Title: Re: My MC 72
Post by: wwwarbird on November 09, 2013, 07:29:51 PM

 Looks good. Maybe I missed it, what's the wingspan and area?

 This is first constant chord wing I've seen you do Sparky, it'll be interesting to see how you like it in the air.

 Looks like you'll be painting next week! S?P ;D
Title: Re: My MC 72
Post by: RC Storick on November 09, 2013, 07:38:13 PM
56 WS. 9.75 cord 2.25 flap. Aprox area is 650.
Title: Re: My MC 72
Post by: wwwarbird on November 10, 2013, 10:02:27 PM
 That's a real nice size Sparky. A big enough model that it could be a solid contender in competition, but yet not so big it's that it's overly difficult to transport. That's a perfect compromise for a lot of flyers.

 "Heads-up" to all of you kit builders out there, hopefully you're watching and considering this one. Just don't forget the glow power option on the plans. S?P ;D
Title: Re: My MC 72
Post by: RC Storick on November 11, 2013, 04:19:30 PM
Well complete wing with flaps is 10.1 ounces. Is that light enough? LL~
Title: MC 72 All parts done. PIC
Post by: RC Storick on November 11, 2013, 09:53:25 PM
All sub assembly's complete. I should have it on its wheels this weekend.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136924;image)
Title: Re: My MC 72
Post by: Duke.Johnson on November 11, 2013, 10:10:49 PM
That fuse looks really nice!
Title: Re: My MC 72
Post by: RC Storick on November 11, 2013, 11:15:40 PM
Thanks it's scale. I was looking back and see that this plane is not 30 days old yet. I should have it all framed up in less than 30 days. The painting on the other hand will take some time. The oil tank behind the spinner will be gold leaf and it will be painted Miss Ashley Red with gold radiator's in all the scale places. It might have working stacks. I took my Mattel Vac-U-Form and made a pilot but I think I will do a detailed cockpit instead. I have seen some great work here and that has inspired me to do it. I also think I can do the details lighter than a pilot.

I am still thinking how I can hide my AMA number like I did on my Tbolt and still be legal. I'm sure it will come to me as I am painting.
Title: Re: My MC 72
Post by: wwwarbird on November 11, 2013, 11:29:40 PM

 Cool stuff. y1

 Just an idea for the AMA number...if you're going to do panel lines you could do the AMA number using the same thin black outline. It would be there, but it wouldn't really be noticeable until you got up very close to the model.
Title: Taped together (pic's)
Post by: RC Storick on November 13, 2013, 12:15:03 PM
Well I am starting to fit everything together. Here is two shots of what it's going to look like. Airframe is 18.5 ounces.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136983;image)

I just ordered dope from Wicks. The gold paint for the radiators must have real gold in it. 28.00 per quart where clear and colors are only 15.00 so almost twice the cost. Thinner is 53.00. I have 3608 but I like to use the same thinners when painting. Less chance for problems.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=136981;image)
Title: Re: My MC 72
Post by: MarcusCordeiro on November 13, 2013, 02:29:53 PM
 8) 8) 8) 8) 8) 8) 8)

Marcus
Title: Re: My MC 72
Post by: Douglas Ames on November 13, 2013, 06:05:16 PM
There's actually 3 CG's - Longitudinal, Lateral & Verticle.

Lateral CG (along the wing span) is more of a dynamic thing as half your line weight comes into play, plus the Cent. force applied to your tip weight. Above my head mathmatically...

I saw a picture of Al Rabe on SSW, hanging his model by the leadouts against a wall to check Verticle CG. If the wing is parallel with the wall, you got it!

Checking Long. CG is a given.
Title: Re: My MC 72
Post by: RC Storick on November 13, 2013, 06:44:15 PM
There's actually 3 CG's - Longitudinal, Lateral & Vertical.
Someone has been listening!  CLP**
Title: Re: My MC 72
Post by: Howard Rush on November 13, 2013, 07:00:09 PM
There's actually 3 CG's - Longitudinal, Lateral & Verticle.

And they're in the same place.  The classic way to find them (it) for a rigid body is to hang it separately by three different points.  The CG will be at the intersection of the three lines that go straight down from the places it's hung from.  Play the cartoon, "Where is this guy's centre of gravity?" at http://www.s-cool.co.uk/a-level/physics/moments-couples-and-equilibrium/revise-it/centre-of-gravity-and-centre-of-mass .
Title: Re: My MC 72
Post by: RC Storick on November 13, 2013, 07:06:32 PM
Is he being slung around on a wire?
Title: Re: My MC 72
Post by: Howard Rush on November 13, 2013, 07:14:09 PM
Lateral CG[/b] (along the wing span) is more of a dynamic thing as half your line weight comes into play.

That one again.  See post 17 of http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=382606&mesg_id=382606&listing_type=search#382738 .  
Title: Re: My MC 72
Post by: Howard Rush on November 13, 2013, 07:41:09 PM
Is he being slung around on a wire?

That is actually a good point, as we discussed elsewhere.  Lots of us take for granted that gravity is an acceleration and so is what the wire by which an airplane is slung does.  It wasn't (the details weren't anyhow) obvious to people before Newton figured it out.  I looked a little on the Web for a good explanation, but didn't find one.  I probably saw it justified somewhere long ago, but I don't remember the justification.  Serge explained this for a living, so he can probably explain it rigorously enough to satisfy the skeptical student.  It works, though, and we use it to design airplanes and inertial navigation systems, and Brett uses it to steer satellites.



 
Title: Re: My MC 72
Post by: Douglas Ames on November 13, 2013, 10:37:15 PM
And they're in the same place.  The classic way to find them (it) for a rigid body is to hang it separately by three different points.  The CG will be at the intersection of the three lines that go straight down from the places it's hung from.  Play the cartoon, "Where is this guy's centre of gravity?" at http://www.s-cool.co.uk/a-level/physics/moments-couples-and-equilibrium/revise-it/centre-of-gravity-and-centre-of-mass .

Agreed.
I was thinking of a "3D ball" that represents the CG with 3 lines running through it - Vert./ Lat. / Long. ...and it moves.
Your chart is interesting but trimming wings level with a buddie/spotter outside the circle is a quicker solution.
Title: Re: My MC 72
Post by: Steve Helmick on November 13, 2013, 11:18:19 PM
Very Interesting

KT

Not so interesting. At the time, we were then looking at Robert's 2-view drawing, so vertical was up/down, lateral was left/right. Had nothing to do with airframes or aeronautics at that point. In a 3-D situation, it's different, of course.

I'm mostly interested in where the fore/aft CG will be, before trimming commences...and after. It's got to be correct, not close enough. Secondarily, is the constant chord wing going to be a deal killer in turbulent conditions?  ??? Steve
Title: Re: My MC 72
Post by: RC Storick on November 13, 2013, 11:21:39 PM
Secondarily, is the constant chord wing going to be a deal killer in turbulent conditions?  ??? Steve

I bet it will be fine.
Title: Re: My MC 72
Post by: Howard Rush on November 14, 2013, 01:26:05 AM
Your chart is interesting but trimming wings level with a buddie/spotter outside the circle is a quicker solution.

Yep.  Just put a wad of ballast on the right tip and take it off until it flies right.  The two-line-reel method isn't even correct and is more bother than just guessing, and guessing on the generous side is safe. 
Title: Re: My MC 72
Post by: RC Storick on November 14, 2013, 08:34:59 AM
Just put a wad of ballast

Sounds right LL~
Title: Re: My MC 72
Post by: RandySmith on November 14, 2013, 08:49:49 AM
Yep.  Just put a wad of ballast on the right tip and take it off until it flies right.  The two-line-reel method isn't even correct and is more bother than just guessing, and guessing on the generous side is safe. 


What constituents a wad ?     ;D


Randy
Title: Re: My MC 72
Post by: RC Storick on November 14, 2013, 08:52:49 AM

What constituents a wad ?     ;D


Randy

That would be the same amount he has in the nose.  S?P
Title: Re: My MC 72
Post by: Avaiojet on November 14, 2013, 08:57:58 AM
Different hinges on the elevator than flaps?

Nice lines, looks good!

Charles
Title: Re: My MC 72
Post by: RC Storick on November 14, 2013, 09:18:02 AM
I was going to try pin hinges but I will be going to all kleet.
Title: Re: My MC 72
Post by: Avaiojet on November 14, 2013, 10:08:47 AM
I was going to try pin hinges but I will be going to all kleet.

OK, but you have what looks like Robart hinges on the elevator?

Will you remake the elevator?

Charles
Title: Re: My MC 72
Post by: RC Storick on November 14, 2013, 10:28:05 AM
OK, but you have what looks like Robart hinges on the elevator?

Will you remake the elevator?

Charles

I do and I will not remake the ele. I will just fix it.
Title: Re: My MC 72
Post by: Howard Rush on November 14, 2013, 11:58:37 AM
That would be the same amount he has in the nose.

Oh, no.  That's way too much.
Title: My MC 72 Progress
Post by: RC Storick on November 16, 2013, 05:09:43 PM
Here is where I am at today. Started on October 21, 2013

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137087;image)


So in 26 days I am close to getting it on it's wheels. Work has slowed things down. All control surfaces are attached. Wing glued ad stab tacked on. This one will be covered with 00 silkspan. I hope to save a little weight there.
Title: MC 72 On its wheels
Post by: RC Storick on November 18, 2013, 05:18:08 PM
 Less than 30 days and its on it's legs. I still need to make some pontoons but hey!
Title: MC 72 pics
Post by: RC Storick on November 18, 2013, 05:23:54 PM
Hatch shot
Title: MC 72 pontoon
Post by: RC Storick on November 18, 2013, 05:50:05 PM
Shape for the pontoons
Title: Re: My MC 72
Post by: MarcusCordeiro on November 18, 2013, 06:10:53 PM
Looking good boss!

Marcus
Title: Re: My MC 72
Post by: RC Storick on November 18, 2013, 06:27:26 PM
resand
Title: Re: My MC 72
Post by: wwwarbird on November 18, 2013, 06:42:33 PM

 The pointy nose "pontoons" look too modern for the rest of the MC design Sparky, better round those fronts off aka Gee Bee... y1

 Lookin' great otherwise though! y1
Title: Re: My MC 72
Post by: RC Storick on November 18, 2013, 09:07:47 PM
The pointy nose "pontoons" look too modern for the rest of the MC design Sparky, better round those fronts off aka Gee Bee... y1

 Lookin' great otherwise though! y1

Look at these

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137295;image)
Title: Re: My MC 72
Post by: Dan McEntee on November 18, 2013, 10:30:55 PM
  Well like Forrest Gump said, since you've gone this far, might as well go a little farther make them look like floats, and include the little step on the bottom that helps the potoon break the surface tension of the water. Just a little zig zag up behind the wheel well. It may be a little cartoonish looking, but painted properly to match everything else, I think it will look OK. I'm sure you'll be making them removable and can always take them off or build different ones.
   Type at you later,
    Dan McEntee
Title: Re: My MC 72
Post by: wwwarbird on November 19, 2013, 12:25:30 AM
Look at these

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137295;image)

 Ha! I figured that was coming. ;D

 If you scale down the red white and gold patterns shown on the pontoons and then paint up your pants to match it would look pretty cool. y1
Title: Re: My MC 72
Post by: Douglas Ames on November 19, 2013, 05:45:17 PM
Looks great!
How are you going to do the faux exhaust?
Lots of ports on this bird.
Title: MC 72 progress pics
Post by: RC Storick on November 21, 2013, 12:45:23 PM
Progress pics
Title: Re: My MC 72
Post by: RC Storick on November 21, 2013, 12:45:45 PM
progress pics
Title: Re: My MC 72
Post by: RC Storick on November 21, 2013, 12:46:30 PM
progress pics
Title: Re: My MC 72
Post by: RC Storick on November 21, 2013, 12:47:29 PM
progress pics.

Ass seen in these shots it weighs 46.5 ounces with everything except covering and paint. So even a 8 ounce finish would leave me at 54 or 55. I am hoping to do the finish in 6-7 ounces for a even lighter airplane. See that a battery compartment can be organized .

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137377;image)



Today this plane is 30 days old. The original idea is a week before, so not to bad for 30 days work. The biggest design factor for this plane is battery placement. We shall see how things go but I am betting this will bring these big airplanes more into the realm of what I like.



(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137381;image)
Title: Re: My MC 72
Post by: MarcusCordeiro on November 21, 2013, 12:54:33 PM
Neat!!!

Marcus
Title: Re: My MC 72
Post by: wwwarbird on November 21, 2013, 01:41:30 PM

 Looking great! y1
Title: Re: My MC 72
Post by: Mark Scarborough on November 21, 2013, 02:19:54 PM
Looks good,,

how is it looking for balance/CG with the battery that far back
Title: Re: My MC 72
Post by: RC Storick on November 21, 2013, 03:04:34 PM
it will be nose heavy
Title: Re: My MC 72
Post by: Dan Bregar on November 21, 2013, 04:34:10 PM
Very, very nice Robert.  Really like the vertical batt. placement.  :)
Title: Re: My MC 72
Post by: wwwarbird on November 21, 2013, 08:47:43 PM
it will be nose heavy

 Don't fret Sparky, you could always bore the rear half of the plane full of holes. Doh! S?P H^^ ;D
Title: MC 72 landing gear treatment
Post by: RC Storick on November 22, 2013, 12:25:03 AM
I thought I would do something special for the LG. So I attached balsa to the CF gear and sanded it into a airfoil. A special airplane deserves special treatment.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137423;image)
Title: Re: My MC 72
Post by: john e. holliday on November 22, 2013, 08:12:29 AM
Don't fret Sparky, you could always bore the rear half of the plane full of holes. Doh! S?P H^^ ;D

Rethink,  bore more holes on the tail of a nose heavy plane!!! S?P
Title: Re: My MC 72
Post by: Avaiojet on November 22, 2013, 04:53:29 PM
Yes, Outstanding!

What are those "areas" on the float struts, cowling and the floats?

Charles
Title: Re: My MC 72
Post by: Trostle on November 22, 2013, 05:08:12 PM
Yes, Outstanding!

What are those "areas" on the float struts, cowling and the floats?

Charles

Maybe it is some form of a new generation X-onobtainium that has negative mass.
Title: Re: My MC 72
Post by: Dennis Adamisin on November 22, 2013, 07:15:45 PM
Looking fair to partly OUTSTANDING!!!

Sparky, where did you get the blue bracket thats holding the battery plug - I have been looking for something like that.
Title: Re: My MC 72
Post by: wwwarbird on November 22, 2013, 07:53:46 PM
Rethink,  bore more holes on the tail of a nose heavy plane!!! S?P

 You got me again Doc, I was thinking backwards there! n~

 Lookin' great Sparky, and with a pilot?
Title: Re: My MC 72
Post by: Howard Rush on November 22, 2013, 10:25:33 PM
Sparky, where did you get the blue bracket thats holding the battery plug - I have been looking for something like that.

http://www.spotonrc.com/category.php?id=40  Local guy.
Title: Re: My MC 72
Post by: RC Storick on November 22, 2013, 11:16:38 PM
http://www.spotonrc.com/category.php?id=40  Local guy.

17.00 there or 4.88 here https://www.hobbyking.com/hobbyking/store/__40718__Anodised_Alloy_External_Flight_Battery_Arming_Switch_T_Plug_.html
Title: Re: My MC 72
Post by: PerttiMe on November 23, 2013, 02:01:07 AM
  Well like Forrest Gump said, since you've gone this far, might as well go a little farther make them look like floats,
As it is not going to be a seaplane anyway, better make it look like a landplane version of the MC 72, instead of a fake seaplane.
Title: Re: My MC 72
Post by: RandySmith on November 23, 2013, 11:33:06 AM
Its  lookin good Sparky  !!
ya know that plane was a twin engine... so you could try 2 E-Flite 15s  :-)

Randy
Title: Re: My MC 72
Post by: RC Storick on November 23, 2013, 11:45:27 AM
AXI makes a counter rotating motor however its too heavy. I did research it.

(http://www.modelmotors.cz/products/thumbs/AXI5330D20.gif)
Title: Re: My MC 72
Post by: Dan McEntee on November 23, 2013, 03:53:33 PM
AXI makes a counter rotating motor however its too heavy. I did research it.

(http://www.modelmotors.cz/products/thumbs/AXI5330D20.gif)

     You ain't got one hair on your a#@ if you don't at least TRY to incorporate the ability to swap out a conventional motor set up for the counter rotating deal and experiment.  LL~ LL~ LL~How much heavier is it? Think of the possibilities? Griffon powered Spitfire, Red Baron air racer, Precious Metal air racer. Let Paul Walker know and he can do a Shackleton Bomber Stunter!!!!!I have always wanted to do a twin and/or a counter rotating type stunter, especially after seeing Randy's C/R model at the NATS in the early 90's. Just haven't had the time to devote to it. I do have a kit of Sheek's Mosquito downstairs, and if I can ever find a left hand crank for an OS .25LA, FP.25, or OS .35S I'll start building the day after I get the crank!
  Type at you later,
   Dan McEntee
Title: Re: My MC 72
Post by: RC Storick on November 23, 2013, 04:01:53 PM
The motor in the picture weighs 54 ounces. That's the smallest CR motor they have.
Title: Re: My MC 72
Post by: Jason Greer on November 23, 2013, 10:36:05 PM
http://www.maxxprod.com/mpi/mpi-266.html

Here are few more options. They have a 6 oz and 10 oz setup.
Title: Re: My MC 72
Post by: RC Storick on November 23, 2013, 10:55:28 PM
Well its a nice thought but having to use 2 esc and the weights involved make it out of the question. To work this plane must come in the mid fiftys.
Title: Re: My MC 72
Post by: David Hoover on November 24, 2013, 07:18:54 AM
But would be fabulous in scale versions of any of the planes Dan mentioned
Title: My MC 72 Last post in this section
Post by: RC Storick on November 25, 2013, 09:58:30 AM
This is the last post on building in this section. I am taking everything apart today and it will get weighed. I will start the final stage of finishing. However as my tag line says the finish starts with the first piece of wood cut. The better you build your airframe from the start the better the finish product will be. So take your time make everything fit and sand everything symmetrical. Look for this saga to continue in the finishing section starting today.

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137618;image)

(http://stunthanger.com/smf/index.php?action=dlattach;topic=33116.0;attach=137620;image)
Title: Re: My MC 72
Post by: Tom Niebuhr on November 25, 2013, 10:13:59 AM
Sparky,
Looking forward to the finishing.

Meanwhile I would like see the bottom of the aircraft. Air exits or any baffling to direct cooling air over the electronics.
Title: Re: My MC 72
Post by: RC Storick on November 25, 2013, 10:29:05 AM
Sparky,
Looking forward to the finishing.

Meanwhile I would like see the bottom of the aircraft. Air exits or any baffling to direct cooling air over the electronics.

I will be running the AXI fan and here is a bottom shot.
Title: Re: My MC 72
Post by: Tom Niebuhr on November 25, 2013, 10:37:41 AM
Thanks,Very simple.

I love stunters that look like real airplanes. Keep up the great work.
Title: Re: My MC 72
Post by: RC Storick on November 25, 2013, 11:42:15 PM
over to the finishing section http://stunthanger.com/smf/index.php?topic=33418.0

Click on picture to be taken to finishing thread
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33418.0;attach=137650;image) (http://stunthanger.com/smf/index.php?topic=33418.0)