Flite-Metal

Hi Don,

That's interesting after two years I would receive a reply from the other half of the
Davey illustration team. Margaret is not aware I purchased everything from Chris.

I will write to her giving her work its praise well worth the year it took to acquire. I
wrote Aviation News no less than five times before I received a reply from a new
employee who found Chris Davey's address and contacted him with my inquiries.

Though it took a year to acquire, the return on my patience was simply "wonderful".
Chris sold me the original "large format" drawings he created for Aviation News's Sept.
1980 issue.

Now to fully appreciate these drawings one must first understand the USAF ordered
all B-47 documentation and engineering records destroyed the day after the B-52
rolled out. This was supposed to include a T.O. (technical orders) issued to all but
online maintenance facilities servicing the then current population of B-47 in use.

Thankfully, the Air Force vets servicing the B-47 took their T.O. manuals home with
them. Remember, this was paramont to "treason" back in the day because Cold War
security was intense, even to FBI home visits... with severe consequence. Looking
back, the FBI turned a blind eye toward these incidents.

When Sam and I began this project there was very little available beyond plastics
and rather broad stroke documentation that regretably for the most part was not
accurate. After six months I developed a decent spider feedback index which led to
the growth of online discussions (in the millions) relative to the B-47. The resulting
dust cloud of inquiries began an automatic filtering process by those reading them.

Its not often you have an opportunity to see the results of a query unfold infront
of you. Today, Googling only three search phrases will result in literally thousands
of Boeing B-47, Boeing B47, Boeing Stratojet, responses. Sam brought this to my
attention a couple of years ago as he witnessed it. He began to keep up with the
resource stats as they exploded. #'s are Sam's life...

Enough about the dust cloud I created, I'll share images of Chris's original drawings
as they appeared in Aviation News Sept. 1980.

Now, to the drawings...

Flite-Metal

This week we should get back on track with our nacelle resizing. The original milling was a test of our virgin,
nedited files...It would be a stretch thinking these would be proper the first go. Unless you have properly
indexed your drawings, one unto the other, you have to re-index. Remember this 158+ inch wingspan design
began with 1/200th and 1:1 resources.

Remember all those full size visited by Dick Reynolds as he and a friend measured them from nose to tail
verifying dim declarations? I believe Dick visited four plus the microfiche review and copying he and Michael performed at the Natl Aerospace Museum in Washington, D.C.. Ad those to Sam's audits of four others to resolve dim issues should witness our commitment to constructing as close to a scale replica as possible while staying within our target F4C 33#

After witnessing what happened to Bernie's, Sam began making proto noises. So, while he's traditionally cooking a/his goose I am measuring and re-measuring after discussing with Javier. We three are on the
same page. One reading this paragraph should finally see what scratch building is all about.

Too often people confuse plan building with designing/aka scratch building. I have noticed a tendency for thread readers to begin following with "In The Beginning" then moved through a portion of "In The Middle",
but not through it without either finding it boring due to my not articulating the process properly...or too much detail. I prefer thoughts of it possibly boring. I do take responsibility for the boring monologue as this was originally intended to bare more dialog.

Flite-Metal

Flite-Metal

..................

Wishing you and yours a Merry Christmas and Happy New Year!

Hope everyone was fortunate to have seen their loved ones who make their annual visit at this time of
year. Enjoy the moments which fleet away too quickly.

Return to your individual projects with fresh charged batteries to whatever aspect of this great hobby
you enjoy. It is, after all, an escape from life's less than finest moments.

May 2015 bring each and everyone of you the finest in R/C flight, building, and competing.

Don Sims

Hope you have a fantastic, restful, relaxing, Holiday Season too Ed!

Flite-Metal

Quite literally there are so many things to be reigned in that overall progress may appear
slow, however it not. Moving from item to item section to section from nose to tail.

Printing, milling, measuring and remeasuring at the model's 1:1 size(s) for all components
and sections thereof.

Below is a horrible, but truely welcome reality our mill is working as it is intended to.

Insightful

Ed, what type of foam did you use and what bit(s)?

Flite-Metal

60# density Hi-Load Styrofoam. Explicit product not a knock-off product. The OEM
product is dimentially stable and square due to its monitoring during the extrusion
process.

We will use some 100# density Hi-Load in some areas where the fuselage wall will be
thinner.

We are currently usng a 3" ball nose fluted bit specifically designed for Styrofoam. A
4" ball nose is on order to permit our Z axis to clear the 3" slab.

The mill utilizes a router at this time and looses some Z height to the difference in a
router and a slimmer high speed motor.

As for the performance difference between a router and a mill explicit motor spindel.
With foam there is no difference between the two motors except the afore mentioned
difference in Z axis depth.

The mill specific spindle below is a slimmer, trimmer, narrower alternative to stripped
down router. However at $1,200 each Vs. $280 each the router is much less. Since I
will see roughtly 500 hours life out of either... You can see why we have a router.

Flite-Metal

The wing is hot wired. Due to the 5 inch inboard flap "thickness" and wing's minimum
skin thickness above it I will probably use High-Load 40 to expedite the wire travel.
The top of the wing is sheeted, as is the bottom except in the flap bays where the
Polyurea will sinch everything without having to glass C/F vail in them.

I'm in a weight saving mode... Every opportunity to shed pounds is being taken to
lengthen flight time. So far, so good

Flite-Metal

I am setting up our Up3D printer. We've had it a long time but something was always
popping its head up to interfere with assembly and installation. With the cockpit CAD
in hand and Cut 3D installed, its time to it.

Secondary are our B-47 wheel inserts.

I will take the time to share this process. If it gets draggie or a wee OCD simply tell
me and there will be an instant fix.

Flite-Metal

Took a few days longer to dig up all the software from the two older computers and fit
it all into this notebook. Below is the front windshield as it appears in the UP3D print
software.






Print bed is 5 cubic inches 5"x5"x5" permitting a one piece windshield. Balance of canopy frame will be comprised of multiple pieces.

Flite-Metal

We'll return with some windshield printing results shortly...Thought you might want a peek at Sam's success
with the CNC mill... ;^) Its been interesting...Sam stuck with it and finally we are seeing the reward for all
his hard work and patience. Aside from being force feed CAD, Sam's got the milling to where surface texture
is nearly perfect, requiring little to no garnet paper touch-up.



Above you see the fuselage nose cap. A removable piece during iniital assembly. It is sealed closed after
the front lower truss is in place. In the lower left you see the exploded edge of the cap caused when a
sacrifical substrait was not used and the bull nose on the bit was not able to run a full quarter inch out
beyond the end.


"Two Pair Of Halves"



"Beautiful Outside Bell Mouth, Half"



Outboard nacelle front.

One of the most difficult shapes on the entire model; only surpassed in difficulty by the inboard nacelle
rear fluting. We call the outboard pylon "row boat" because it looks exactly like one viewed from above.
Note pylon leading edge doubler. There is a subtle fillet transition between nacelle and pylon. Sam use
of mill path overlap permits as smooth a surface as possible, even with only one 45 deg. clean up pass.



Half Row Boat interior foam is hot wired to receive pylon's EDF fork blade. As described earlier, both the
inboard and outboard nacelles are removed for maintenance rather than having to do it laying on my back.
Dick Reynold's early CAD work was edited to a water tight state before milling could occur.



After an internal hot wiring of the inlet and exhaust outlet the inlet ellypse is rounded over by sanding.

Now, on to the windshield while Sam mills the inboard nacelle and pylon halves.

Flite-Metal

Your comments and questions are welcome. Sam is monitoring this thread to answer
questions relative to our Black Toe CNC Mill "Kit", power supply, integration board, &
our use of Aspire's Cut3D to visualize the cut file results prior to physically cutting.

By no stretch of your imagination would our system be considered expensive. It has
an UP3D printer from which you will see components shortly; Aspire's Cut3D for CNC
mill path setup and creation of the final .stl cut files, Ashlar Vellum's Argon CAD 3D
editor, Black Toe 3 axis CNC mill with electronics controller board for four axis, one
Power PC for CAD editing & number crunching, DevCAD (includes auto-trace utility),
4 axis CNC hot wire cutter, and NextGen 3D laser scanner.

Flite-Metal

Speaking of Sam, He's been busy with the CNC mill. Here are a progression of images
showing how the fuselage front steadily grew slice by slice to its final shape.

Don Sims

Looks like a minimal amount of sanding will be needed or is there a plan B?

Flite-Metal

There is virtually no surface sanding. The redish highlighted area below is final foam surface. At this point
some foam is coated with Polyurea Resin prior to covering with Flite-Metal.



Depending on flight load there are sections laminated with balsa and fiber glass prior to application of
Polyurea Resin then Flite-Metal. Below is the surface of the fuselage sans tinting so you can see how
increadably smooth it is.



Don,

Perhaps I should ask what would be the reason for a "plan" B? This is all facade attached to the central truss
and the inner truss extensions. All flight and landing loads are borne by the diamond external and internal truss.
At this point we are simply performing assembly tasks with components resulting from the last four years work.

Ed

Don Sims

Didn't know if you planned to sand off or fill in for the finish. Fill in was plan B.

Flite-Metal

Normally when one mills they are just a little over size. B-47s are being milled to four decimal places...which
pretty much puts us right at 00x00x00 deviation from the 1:1 shape when the CAD drawing is correct.

Richard's original CAD files were not water tight so we have been editing as best we can as we have moved
across the airframe. There are occassional apparations which occur along "mirror lines". We corrected one of
those this evening.

Radome on chin of the fuselage was created when Richard drew the left half. Along the perimeter of the left
half there were polygons which had not been processed as NURBS to fill in space that appeared as depressed
polygons. These depressions were going to have to be "filled in".


This is a water soluable (surface smoothing and clean up) balsa filler which works great as a Styrofoam divet filler.

It has a geletin base which is chemically neutral to virtually everything one might want to coat over it.

Woodland Scenes model railroading Styrofoam filler:



Here's the way it looked after Sam-I-Am finished milling it.

Sam-I-Am

For what it's worth, let me comment on what you are seeing in the sequence #191 above.

The CNC is running through its rough cut mill path removing approx. a 1/8" wide by 1/8"deep channel on each pass, each of the contours is a 1/8" height difference all the way down to 3" in depth. This path is used primarily to remove as much waste material before you get to the finish work. The finish path is just that, a tool path which follows the contour of the final surface with each parallel path offset by 0.001 of an inch making a very smooth surface to the touch. So far after about 80 Hours of playing with settings on this mill, the only imperfections in the parts are an occasional facet in the model that doesn't solve properly or an occasional foam "grain" imperfection.

The major learning other than the usual newbie mistakes you make with a new piece of hardware and too much time on your hands, is how to hold down the work piece and get a good finish in the edges without chewing them up.

Using similar materials like foam as a sacrificial backing for foam pieces or MDF for plywood eases the transition of the bit in and out of the work piece. To get a crisp edge you need to mill down past the end of the piece to get on the flush cutting side of the bullnose bit.

Seems the obvious thing to do now that I saw what doesn't work well.

Flite-Metal

Seems everything these days has issues Welcome to the chin radome in all its width, length, and depth.





The old way of gluing donut cut sections of foam sequencially will be exceptionally difficult to maintain positioning,
though it will work if absolutely ncessary.

Flite-Metal

I suppose at this point Steve must have been bored and stopped following this thread. We are
making sectional components with which to assemble our first of three versions of the Boeing B-47.

Sam's B-47 Weather Bomber presents so much eye candy and packed with so much story telling
about how these were the only one's to be fired at by a Russian/Cino Mig during the coldest of the
cold war.



Excuse the distraction...here's the weather bomber...

Flite-Metal

No, we are not in Venice...though the inboard nacelle outrigger door looks like a gondala.

The outside parallel lines represent the hinge line parting point of the outside perimeter
of the door.

Flite-Metal

Need we say more?



Milled to the nacelle centerline enables easy door location. Like if you don't know where the door cut-hingeline
falls you have to walk backwards into it... Wee busy round here today.



And you wondered what all those thousands of lines were there for... ;^) Individual passes of the mill
across surface of the foam. We're not entirely water tight and its showing up early every day.

Flite-Metal

Below are resulting cuts from Sam's working through the hours required to achieve either
a properly milled part, or an anomaly which prevented success.

We tend to think of ourselves as being successful in this endevor; even if its only to our
latest successfully milled part...

I have a stack of parts to print so we're back to it.

Flite-Metal

Don't know why I didn't receive the notice of your post back in May.

"Iron Man 3" was OK, don't know how he continues to endure the demands
he's put through. Robert... not the movie character

Oh this is getting "hairy"...dealing with the slip tolerance of the inner truss
to the carbon fiber vail cavity created for it.