Mc Clain Wing Cores 48" virgin foam and EPP flying wing - Page 3 - RC Groups
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Aug 06, 2008, 09:39 PM
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links . . lets try again

lets try this and see if these links work:
Last edited by pval3; Aug 06, 2008 at 09:52 PM.
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Aug 06, 2008, 10:08 PM
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motor choices

I want to clarify the direction of the build as I had an email earlier asking why I was not making this a speed racer version.

There a bunch of super fast, super aerobatic flying wings out there with 48" spans. The best of them is probably the Rite 48" wing. These are fantastic wings but the newer modeler is not going to have an "easy time with set up and handling these wings. The slow speed range is not designed for this either, these are all designed to go fast and make your tail spin.

This wing can do the same thing. It can be built with a heavier spar, heavier battery and a bigger and faster motor along with covering it with .25oz can do this if you want BUT

The purpose of this build is to provide an transitional model that will allow the guys that have a wild wing and want something with a little more performance the ability to transition all their equipment into this airplane and discover the fun this design has to offer.

As we are going to build this light, using a light motor, we will also be able to use a lighter battery that will get the wing loading way down. With the airfoil that is on this plane, I believe it will thermal as well as scream at a reasonable speed ( a little faster than a wild wing with the same power plant.)

Here in inland NC, we have no viable slopes so anything we have has got to be able to fly out and up to get to the lift zone and be light enough to take advantage of the limited lift. Thermalling is viable, far better than the a "cross genre" wing would be a blast.

The 36" version was too fun on the slopes at the beach, even in crummy conditions it was a hoot to fly, but the wing loading was just not there for thermalling. The 48" wing is differnt, I truly belive that this plane can serve three masters well as a thermal slope and barn burner although the top end will be limited to about 80 with the lighter weight spars I am going to use.

I am still cutting this out for my 3000mah 4s pack - just in case . . .but I am only doing it to ensure I have the space for whatever battery I decide to use. I will use strips of epp cut to size and tack glued into the compartment to house smaller batteries down to a 1000 mah 3s 25c pack. . . . .

So - - -with that . . on with the build
Aug 06, 2008, 10:17 PM
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building update

I have been building and taking lots of pictures over the last two days but am trying to assist my wife with a few projects too. Posts will be in bulk so bear with me....I also am building the starfire at the same time with two building desks that area also being used by my wife for her projects and my daughter's art easel that we are working on together ....

My wife bought me two new tools for father's day this year and I am having a bear of a time getting them to "fit"...I got a nice drill press and a Craftsman 22" jig saw . . you can take almost a full sheet of hobby ply through this thing without banging the back but it takes up 1/3 of my building area . . .the drill press takes up about another 1/4 leaving me not much room for anything else . . .

man I love the tools but I already need a new garage!
Aug 06, 2008, 10:43 PM
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Hi Phil,

I know what you mean about space to work.

Aug 06, 2008, 10:57 PM
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paulvi thanks for posting in the thread. It really helps when the data is all here.

folks, please understand that emails to me and pms do not help others....I have this thread on instant notification so when you post a question in this thread, i get it right away and i can respond to it in the thread so everyone can have the same information and answers to questions that I am sure they thought of too.

Please be courteous to all and post in this format.

the question asked was what is the difference between the all epp version of this wing and the virgin foam/epp version.

The epp version is better if you are going to build it using the henry's cloth with the 3m spray 90. This is the most durable way to make this plane and it is almost bullet proof but it is also heavier.

The epp/virgin foam version (my build) has the advantage of a tough resistant leading edge made of epp that resists dings and beating but has the rigidity and very light weight of the virgin foam for the majority of the wing. It is also cheaper than the all epp version because the materials are considerably less.

the virgin foam is a little more straight forward to work with where the epp must me supported properly and finished properly or it will me too flexible.

Hope that answers it . . .if anyone else has a better explanation I am all ears . . . .
Aug 07, 2008, 02:59 PM
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weight and balance with the new configuration!

Hey guys.

I got all the pieces together in one place and put them on the scale before I joined the wing. I also added a "blank" for my keel (yes I am making another one) and the spars.

With everything using the 2400 mah 3s pack, my total weight of the entire build was 1 lb 4.7 oz . . . wow!

considering that I can go as small as a 20C 1000 mah battery with the low draw tower pro motors - which weighs 1/4 as much as the 2400 mah pack we have the potential to loft this thing airborne under 1 lb - with all the wing area . .. . all I can say is WOW . . .

guessing a prop speed somewhere around 60 mph on the very conservative side, this is looking like one fun airplane that will climb faster than a home sick angel and stay up there for a long long time.
Aug 07, 2008, 11:57 PM
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the hardware

I have opted for the slide on motor mount for the 8mm outrunner base. This is available just about anywhere that sells these towerpro motors.

It simply slides over the 10mm motor bearer and has a round 8mm side for the motor. . mounts the same as any of the other mounts but it has a round hole rather than a flat plate and a screw pattern

using the 9 gram tower pr o servos as they are the lightest, highest torque and seemingly most durable of the lower end servos. These seem to be everywhere on the wild wing thread and from what I see at first glance and run up on my system, they seem to be increadibly impressive (I try to stay with the gws or jr but with the ecomony making a downward spin . . ) these servos are pretty nice!

ESC is a 30A lower end that I picked up through hobby city for this build. the RX is the gws pico 6ch (6 because my 9 other 4ch rx are in other planes - is that wrong??? )

that is a hecktronic 1700 pack in the back ground just for powering up the pieces to make sure they all work and are zeroed out before I event THINK about putting them in or around a model (nothing is worse than having to gouge a servo out of a just finished wing because you forgot to center it before you installed it!)

All up, the set up is as described above in so far as weight.
Aug 08, 2008, 12:00 AM
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where and how to mount that motor

lay it out

Mounting the motor is by far the most critical part of this build as it will dramatically effect the performance if it is off.

We are going to use a stick mount for the 8 mm shaft on the tower pro out runner.

WHat I like best about these is that they are very thin and very light and are cut to fit tightly on the 10 mm sticks I use for mounting most park sized motors. I get mine from the local hobby shop, 3/8" is pretty close and it is basswood.

These take up very little space so you can mount them close to the center line of the wing and reduce the down pressure that the other mounts produce because they lift the motor so high above the thrust line.

Cut at least 3" of stick and mount your motor to the mount then your mount to the stick.

I initially cut for a 6" prop but redid my set up with a 9" prop in mind as 8X6 to 9X4 seem to be the prop of choice on this motor.

You want to sink the motor far enough back in the core to keep the cg forward as possible and balance the battery out.

Mark the cg n the bottom of the cores to get a round about idea of where you need to me and mark that point with the motor and mount
Last edited by pval3; Sep 10, 2008 at 01:01 PM.
Aug 08, 2008, 12:04 AM
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lay it out 2

lay it out two

As the "plans" for this kit are wide open to the interpretation of the builder for configuration, slope or power or thermal, we are planning to set this one up powered with an outrunner.

Because there is no set point for a thrust line, we need a little TLAR engineering.

I can not even begin to tell you how many times I have found myself faced with this dilemma in the past trying to convert something to E so here is my little trick to get it close.

Take the CG point on the wing and draw a vertical line at the root.
Take the center of the LE and the center of the TE and draw a line as close as you can connecting all three lines.

As this is designed to run fast with a slightly larger prop and more trust than the "racing type set ups . . . plus the motor is relatively close to the thrust line, we are going to start out setting up the motor with slight down thrust in relation to the thrust line (that is the line you just drew.)

The closer to the thrust line you get the less likely you are to have pitch up or down when accelerating or decelerating.

I am going to use a 10mm sq beam mount and placing most of it in the foam. I would normally dig into the foam but I think the Center of Gravity should work with this particular motor as it is relatively light in relation to ther similar output motors.

Draw a dot through the center of the leading edge
Draw a dot through the center of the trailing edge
Draw a dot through the Center of Gravity
Connect the dots

Make all changes in thrust line from the center of gravity.

My motor mount beam will be at least 3" long but would be better if it extends slightly toward the center of gravity.

I am going to set the Motor thrust push the nose down slightly when the power is on. I am going to tilt the front of the motor mount bearer up 2 degrees from the 0 line I drew.

If you are using a high power motor for speed. I would use at least 1 degree of down thrust..

motor mount

once you have established the thrust line, mark it on both halves of the wing at the root.

Take your motor mount mount and figure how deep it must go to allow for it to me flush with the bottom of the wing.

Mark the line.

Move to the bottom of the wing and subtract the thickness of the keel from the total width of the motor mount. divide by two and mark the width of the beam on the foam.

Now you are ready to cut the slot for the motor mount.

Start with a metal straight edge and a new razor blade. start slow and even gently pressing to the proper depth. Move the the side and cut in parallel to your building surface on the line you marked.

Do this for both wing halves making sure it all lines up

as I said, I started out with a 6" prop in mind then realized I would be way under propping this motor so I redrew the lines to accommodate up to a 9" prop. the distance to open up the trailing edge in this case was 9.5" (1/4" on each side to clear the prop)

Mark it

Take a NEW razor blade or exacto blade and gently cut out the area fro the prop then prepare to mark the center line on the root to make the cut for the motor stick itself
Last edited by pval3; Sep 10, 2008 at 01:37 PM.
Aug 08, 2008, 12:08 AM
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lay out 3

compare and contrast

I have a 4s 3300 mah pack under the 3s 2500 mah pack. big difference but the 48 mcw can accommodate either without an issue if you really want to go insane with the power. I just so happens that the 300 mah pack is the same weight as my older 8 cell 1000 mah nmhi cells too . . versitiliy for those that have older cells and want to try something new with them.

I am cutting the wing out to accomodate both of these batteries. I will cut for the 3300 mah pack then use epp strips to reconfigure the hole for whatever power/ motor combo I would like to use.

Mark the battery outline on both the top and bottom of the wing using the root as the guide to line it up so you can see where you are going once you start the cutting process as well as the spar layout.
Last edited by pval3; Sep 10, 2008 at 01:09 PM.
Aug 08, 2008, 12:12 AM
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As I was trying to match the common threads in set up with the Wild wing configuration, the overwhelming servo of choice are these 9gm hecktronics servos.

I was amazed at the specs on them as they come pretty close in torque and speed to my JRs.

They are close but they do have some cogging and are slightly noisy . . but at 3.49/ea, you can not come close to bang for the buck.

I have had several other inexpensive servos over the years and have never been really impressed with any of them. Even the HS55's are inconsistent and have brittle gears. The blue bird servos were ok but the cogging and jitters were always an issue and they drove me nuts with quality control as about 1/10 was DOA.

I know, these are cheap servos and I should spend more . . . . but why?

I can buy three of these to one HS55 and after comparing them side by side can say that these are just as smooth and center just as well - and for 1/3 the price!

I stopped buying the HS55s about two years ago as I could not get the consistency I needed considering what a bear it is to retrieve dead servos from a finished wing. The price difference between the HS55 and the base level JR micro was such that the law of diminishing return kicked in and the higher quality servo had a greater value.

I bought 10 of these and all worked the first time out. They all worked as well as any of my hs55s and I have no reservations recommending them. I can understand why they gain such a following in the WW thread.

move your servos so they are as far forward as possible and out so that they are out of the travel of your prop.

I put mine so that they and the servo pushrod will end up in line with the airstream to reduce drag.

Use a ballpoint pen and make sure that you trace as close to the servo as possible.

At the top of the servo where the arm will be. Make a 1" long by 1/4" wide oval right where the arm will travel.

Do this on both sides of the wing
Last edited by pval3; Sep 10, 2008 at 01:24 PM.
Aug 08, 2008, 12:22 AM
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what a monster pack!

Here is the servo and battery outline drawn on the wing
Last edited by pval3; Sep 10, 2008 at 01:28 PM.
Aug 17, 2008, 11:19 AM
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I am going to use three spars, two on the bottom of the wing and one on the top across the two wing halves. This should provide plenty of support for the plane at moderate speeds. I am also using pultruded carbon fiber tubes rather than the usual rods. I find these to be far more rigid than the rods and about 1/3 the weight.

Take the location of the radio gear, battery and motor mount and mark your location to avoid these when you cut down to sink them into the foam.
Sep 10, 2008, 12:48 PM
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haste make waste - learn from my mistake!

Hey folks

Well....when they tell you that gorilla glue foams a little, they are telling you based on a low average relative humidity in the room you are working. I made the mistake of rushing to get the spars set and left them overnight while the humidity was wayyyyyyy up there . . .typical south eastern summer humiity and man did I get a lesson!

The issue is that I set up a critical part of the plane in the beds then went to bed leaving the foaming traits of the glue by the way side . . .

When I came down in the morning, both the 48 and the star fire were lifting out of their beds from the glue expanding dramatically.

I have never really seen this but then again, I have never tried to set up spars while it was as humid as it was!

What I got was a warped mess with the spar lifting out of the core 1/4" at some points.

This makes for a messy dillema!

Now - I used regular gorilla glue on the starfire and the white - fast drying / low foaming formula on the 48 mcw . . .there was no differnece in the foaming of either once the humidiy is added into the equation!

The only difference is that one foam explosion was yellow and the other was white!

What a mess!


The fix was that I had to dig BOTH the spars and the glue out and redo the whole area . . all because I left this unattended for the entire drying process.

What I learned from this

1) never glue the large critical areas whithout checking up on the process at the 15 /25 and 45 minute points once you set the spars.

2) Make sure you weigh the whole thing down . . .the entire span (like I showed in the 36" build) so that there can be no uneven pressure on the spar. This keeps the glue in the joint even when it expands.

3) do not use more glue than you absolutely need as more = more mess and spread out when it expands . . if it gets outside the spar channel.

4) try not to use the gorilla glue when the humidity is very high (if it's raining - wait) unless you want the foaming action...

Digging these spars out was done with a dremel tool and a router bit and the spars were unusable once I finally got them out!

Sep 10, 2008, 01:54 PM
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spars 1

spars 1

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