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B-47 1/16th Scale, 6 EDF Model

Old 07-17-2010, 09:40 PM
  #76  
Capt. Midnight
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Default Refuel Door Actuation

Hi 'Voyager'!

I'll defer to Ed on this one, but my guess is there's some sort of mechanical (maybe electric-powered?) torsional linkage that rotates the door open/close. As you noted, there do not seem to be any actuator arms attached to the door. If I could get a copy of the -2-8 T.O., I'm sure it would explain the details.

How about the answer, Ed??

Cheers,

Dave P.
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Old 07-18-2010, 02:21 AM
  #77  
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Default Replicating Documentation ?

Originally Posted by Capt. Midnight View Post
Hi Ed! Thanks for the photos!! If anyone has any good 'data' on these sets, please let me know. Cheers,
Dave P.
Dave,

Are you going compete with this B-47? If so, all you do is replicate a photo walkaround and multiple view drawing for AMA and Scale Masters.

You are replicating documentation...not building a model to museum scale specs. You don't have to replicate anything that can't be seen in a photo walkaround or a multiple view drawing when viewed from 15 feet away from the model. The craftsmanship judge comes within four feet of it but every onther judge has to be 15 feet away.

Ed

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Old 07-18-2010, 02:25 AM
  #78  
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Default Fuel Door Opening

Originally Posted by Voyager2lcats View Post
Okay. Technical question. How does that flap covering the refueling receptacle open and close? I don't see any mechanical arm or gearing on it (makes sense, as you don't want messy shapes foiling your air flow). Is there gearing or a pinion insided the refueling port cover to crank it into place? I know it is immaterial to modeling this aircraft, but I am really intrigued. See how you've got me interested in this Ed and Dave?
Quite simply, the fuel door opens forward "into the air stream" hinged at its forward base. Door mass fills the cavity when closed. I have already posted images showing interior when open. Its apparently hydraulically operated considering the amount of energy required to open it into a 600 mph air stream.

Originally I thought it rotated to minimize air resistance to the motion. No, it literally opens "forward" on hinges. Below is an animated gif I created from film footage showing it open and close. It is shot in the dark for some reason and you have to know what you are looking at to understand it.



Yes, I get the "door prize" for all the research I have done on the B-47E IV. As I announced on my thread, all the documentation is available on a single CD....about 700 meg worth.
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Old 07-18-2010, 03:45 AM
  #79  
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Default B-47E IFR Door and IAS

Hi Ed!

Have no intention of entering any competitions with my model, but I do like to replicate certain 'major' features, so will include the door; probably will include a capability to open it (manually).

I'm not sure that the door would be hydraulically powered, but perhaps it was. As far as I can tell (from the various photos) the door is pretty much just a 'door' - it doesn't fill up the cavity where the tanker refueling probe is inserted into the aircraft's receptacle.

Also, the refueling IAS for KC-29/-50 tankers was very low - probably (I'm guessing) around 175kts (probably lower, and in a slight descent at ca 12,000 ft, or lower), maybe with 1/2 flaps; when the KC-135s were used, I presume they could go to higher IAS values, and probably much higher altitude (20K??).

You can do the conversion from IAS to TAS (depends on temp., altitude, etc.), but I'm sure the TAS was way below 600kts/mph. I can't remember the airspeed we used in the B-52 (with KC-135 tankers), but I think the altitude was on the order of 25K. Of course IFR for the B-52 was totally different than the B-47, but I'm guessing IAS at 25K was on the order of 250-275kts.

Cheers,

Dave P.
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Old 07-18-2010, 03:44 PM
  #80  
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Default IFR Door In Daylight

Dave,

I encourage you to compete with your B-47. Good heavens man, you have tons of Scale Masters and AMA scale events going on all around you. The only busier place for competitive flying scale modeling is in the Ohio Valley. After all the B-47's flight plans are the simplest you could ever perform.

There is bound to be an attachment of some kind at the inside base just above the hinge points on either side of the base. Look closely above you will see the none moving hinge attachment on the right.

I do not have a close photo in enough light to view motion attachment. You could be correct in that it may have been opened electrically. I imagine a simple hydraulic assembly powered by an electric motor would be small in that cramped space up front.
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Old 07-18-2010, 06:11 PM
  #81  
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Originally Posted by Flite-Metal View Post
There is bound to be an attachment of some kind at the inside base just above the hinge points on either side of the base. Look closely above you will see the none moving hinge attachment on the right.

I do not have a close photo in enough light to view the motion attachment. You could be correct in that it may have been opened electrically. I imagine a simple hydraulic assembly powered by an electric motor would be small in that cramped space up front.
Ed and Dave, I would imagine there might be a type of worm gear driving the door open on the inside hinge areas (left and right). That seems like the most space efficient way to prop that baby open into a moderately strong air flow. Probably driven by a small hydraulic pump- they can get pressure going pretty fast. I obviously don't know for certain.

Bob
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Old 07-18-2010, 09:03 PM
  #82  
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Default Film of later B-47 refueling- note fuel door location.

While obsessively hunting for info on that silly fuel door, I found this youtube video at this website: Air Refueling Archive http://airrefuelingarchive.wordpress.com/category/b-47/

here is the direct Youtube link: [media]http://www.youtube.com/watch?v=UNk5OcOiXjE[/media]
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Old 07-18-2010, 09:46 PM
  #83  
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Yes I am insane. Here is a Google book link on the B-47 with some nice interior photos: http://books.google.com/books?id=1QO...page&q&f=false
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Old 07-19-2010, 04:15 AM
  #84  
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I just love both these B-47 threads running here. Too much desire, not enough pocketbook right now.
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Old 07-20-2010, 01:43 AM
  #85  
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Default B-47E IFR Door

Hi B-47ers!

I've pretty much finished the IFR door; see attached photos. I'm not too happy with the hinge at the bottom of the door, but trying to duplicate/model the aircraft's door hinge system seemed like it wasn't all that important. I may 'upgrade' the door if I ever get the -8 T.O.

Cheers,

Dave P.
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Old 07-22-2010, 11:15 PM
  #86  
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Dave,

I found a photograph of a work group during the mid 50's redesign of the bomb/nav station. If you are still working up detail in that area I will post or email to you.

Ed
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Old 07-23-2010, 12:11 AM
  #87  
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Default Bomb/Nav Station

Hi Ed!

Thanks for the offer, but I'm done with the crew area. If I had one of those 'spy cameras', I'd take a photo of my bomb/nav crew member in his seat; guess I'll have to email the CIA and see if they'd loan me one (of the cameras).

Have finally located a copy of T.O. 1B-47E-2-1 and will copy some pages from it when I go to the Seattle Museum of Flight's archives office. Also, expect to receive a copy of a USAF film of a flight of a B-47 from China Lake to (my old SAC location) Castle AFB; don't know what's on it, but will let you know.

Your flight planning seems to be advancing with the speed of B-47 light. Will you have a crew member in the back seat calling out your airspeed, or a radar detector at the field??

Cheers,

Dave P.
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Old 07-23-2010, 12:50 AM
  #88  
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Dave, just checking in. Your B-47 is looking great. Love the detail- especially the aerial refueling intake door.

Bob
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Old 07-23-2010, 01:23 AM
  #89  
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Dave,

A competitive flying scale model project begins with a "flight plan". The flight plan is 9 maneuvers flown during a single round at a contest. Aircraft are grouped
within specific families with similar flight characteristics and mechanical limitation. Each group or family has a distinct flight behavior which when replicated are
referenced as prototypical to the family they belong to.

You don't typically find someone building something then deciding to compete. Scale models are replications of a specific 1:1 the modeler wants to present for
comparison to documentation they gather "prior to constructing and replicating" by judges who literally compare the model to the documentation from 15' away
in most domestic events.

There are two elements comprising a competitor's score. Each is equal in value...50% of the total contest score. (1) Static score and (2) Flight score are added
together for the contest score at USSMA and AMA events. Multiple judges compare the documentation you provide to your model and declare a value for each
element of the comparison. Flight judges (usually a pair) compare your performance of the flight maneuvers you declare to the written descriptions of each flown.

Your flight plan is written down on a flight round score sheet. There are typically no fewer than three rounds. The two highest flight round scores are summed
and divided by two for the flight score portion of the contest. Added to the static score and you have a contest total score.

Aside from the 9 flight maneuvers flown each round there is a 10th score value per round..."realism in flight" or "flight realism". This is a value for how realistic
your flight maneuvers matched the family of aircraft your model belongs to. This is often referenced as overall round realism. The 10th score reflects how your
round replicated a 1:1 aircraft of that type. Were your angles of attack, overall maneuver smoothness, and presentation representative of the full size aircraft
you replicated.

As I have stated before, this is sport scale modeling. All flying scale modeling in the US is sport scale except for FAI competition. You are not building and flying
a museum accurate replica. You are competing with a hobby level replication of the documentation you gather and present for comparison to your model. The
score is the value of your model's accuracy.

The only absolute requirement is a representation of a pilot has to appear in the cockpit area. How closely your pilot replicates the look and size of a pilot in the
cockpit of a 1:1 of that aircraft type is where the points begin to accumulate. For some reason, many people feel scale contests are nothing more than opinion
points awarded contestants by airplane experts. This is not correct. The judges are comparing what "you" provide for comparison material in your documentation
binder...and your flight maneuvers to the published maneuvers.

A decent example of a documentation binder can be seen here:
http://004edc4.netsolhost.com/Docume..._YC43_Docs.htm

Here are flight maneuver illustrations with descriptions of each...with typical faults:
http://www.scaleaero.com/fltman1.htm

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Old 07-23-2010, 01:30 AM
  #90  
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Default Flight Plan

Hi Ed!

Not sure what caused you to comment on your flight plan, but it sounds great. I was just wondering (tongue in cheek) about your airspeed ...

Cheers,

Dave P.
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Old 07-23-2010, 04:20 AM
  #91  
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Dave,

I was just sharing a little of how simple it is to compete vs. what many people try to make it sound like. With the attention to detail you have shown I am
not so sold on you "not" competing...

I encourage you to get comfortable with your B-47 then go to a scale contest and compete in the fun scale class. That will get your feet wet with a bunch
of newbees.

Your project will weigh so much less than mine for the little difference in physical size. Built up is so much lighter when it can be achieved down at your B-47's
size. Anything laarger than your B-47 and the weight ramps up really fast.

I have no idea what your air speed will be. Do you have any idea? Based on the F-15 flying at 45 pounds with a pair of Dynamax with an air speed of 140+mph...
I will be happy with anything between 80 and 90 given that will provide the duration I need.

What batteries and ESC are you going to use?
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Old 08-08-2010, 03:47 AM
  #92  
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Default Raceway Doors

Hi B-47ers!

Have the LH raceway doors installed, but not quite finished. Will try to do the other half tomorrow and post pics of both sides.

Cheers,

Dave P.
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Old 08-08-2010, 07:00 PM
  #93  
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Wow, Dave! Really nice.
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Old 08-13-2010, 11:11 PM
  #94  
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Default Raceway Doors Update

Hi B-47ers!

Well, after some fussing and fuming, I'm going to call the raceway doors good enough (except for some interior paint); this has not been fun, but it's done, so here's a couple of photos showing all the doors. I had some scraps of 'Flite Metal' from my TSR-2, so added a strip between the forward doors just to see what it will look like (I'll use heat-shrink fabric for the model, but after a little buffing, the 'Flite Metal' looks fairly close to the aluminum).

I'll start on the wings next.

More later; cheers,

Dave P.
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Old 08-13-2010, 11:30 PM
  #95  
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Dave,

Looking good....I can tell you are running shy on patience...ready to fly it aren't you .

You finish...aka buff or sand Flite-Metal off the airfame. On a model this small you could easily match the finish of a B-47 in seconds per panel. Tape Flite-Metal down to a perfectly smooth surface...glass or aluminum sheet and wet sand with 300. In seconds its "The Look Of The Real Thing".

The alloy density and tint has to be compressed for a 1:16th scale B-47. Application to a B-47 is in narrow wrap around panels from the bottom up on the fuselage aft of the cockpit. Application from this point forward is top down in narrow panels.
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Old 08-14-2010, 01:31 PM
  #96  
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Default BACXXX & Incidence AKA Angle Of Attack



I acquired an online airfoil application which provides information in clearer graphic form than the one I orginally posted 10.2% B-47 results with. You can print directly from the online application... It contains over 1750 airfoils! http://www.worldofkrauss.com/foils/1423

BACXXX foil of B-47 appears below with angle of attack effeciency graph. Note the maximum lift effeciency is between 6 and 7 degrees then it falls off the sled. If you have the batteries to sustain it the model should fly like a kite.


Thickness:11.3%
Camber:1.4%
Trailing edge angle:15.0
Lower flatness:49.5%
Leading edge radius:0.8%
Max Lift CL:1.231 CL= Lift Coeff.
Max Lift CL angle: 8.5 CL= Lift Coeff.
Max Lift/Drag L/D:41.464
Max Lift/Drag L/D angle:7.0
Max Lift/Drag L/D CL:1.077 CL= Lift Coeff.
Stall angle:8.5
Zero-lift angle:-2.0


The online application will generate SVG images that can be scaled, printed, plotted, scanned, CAD'd, CAM'd etc... The images below were generated by AID...copy pasted into Microsoft's Image Composer then saved as a .jpg for posting here.

I could have just as easily saved as .dwg, or .dxf for milling or hot wiring the entire wing. The online program will provide the entire wing by number of "ribs" for a built up wing.

The best way to do that is declare a shorter cord let the program generate the foils. When generated, copy~paste image then edit it to resize to your requirement. Note, the plot is leading edge justified... After considering sweep you can draw spar slots, etc...enlarge and save accordingly to the need.

Before you ask what Moment Coeffecient is... http://www.centennialofflight.gov/es..._coef/TH14.htm


Airfoil aerodynamic characteristics. Figure (a) shows the aerodynamic force acting on an airfoil. This force may be separated into lift and drag components, as shown in figure (b). Figure (c) illustrates lift, drag, and moment about the quarter-chord point-all a function of the angle of attack a while figure (d) shows the lift, drag, and moment about the aerodynamic center. The above is illustrated with a 25% aerodynamic center. With the 36 degree sweep this illustration is augmented between root (airfoil @ side of fuselage) and tip.

The Boeing supplied CG data was based on 25% of MAC...on the B-47's 36 degree 38 minute rearward sweep.


Hope this is considered helpful... for your thread followers.
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Old 08-18-2010, 03:45 AM
  #97  
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Default LH Outrigger Gear

Hi B-47ers!

I'm waiting on some feedback from a guy on the B-47 wing airfoil (BAC 145 vs BAC XXX), so decided to build one of the outrigger gears. Attached photo shows almost-complete version - need to do a bit more trimming, etc., but it's basically 'good enough.' The 'oleo' does work, and all I need is some sort of mini-max retract to make the thing work.

More later; cheers,

Dave P.
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Old 08-25-2010, 05:18 AM
  #98  
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Default B-47 2,3 Engine 'Pod' Mockup

Hi B-47ers!

Have about given up on getting feedback from the guy on the B-47 wing airfoil, but will give him a few more days. In the meantime, fab'd a mockup of the 2,3-engine pod (photos below). This turned out to be (just about) a "B-47 Too Far" (from the Allies attempt to take 3 bridges during WW II): building this assembly for the model may be more than I can handle, but will fiddle around with it a bit more.

My previous strut assemblies are no good, so have to redo those dang things. Trying to find a 'reliable' fan/motor for this model (at my 1/16th scale) is also turning into a major problem: there are units available, but reliability seem questionable; no sense building this kind of model unless the engines can be depended upon.

Think I have the outrigger wheel strut and retract figured out, but assembling 2 fans and constructing the ductwork and all the complex fairings may be more work than I want to get into. Some reasonably detailed/dimensioned/cross-sections and other drawing/layouts would be a big help, but there are none available as far as I know, so have to rely on my 1/72 plastic model.

More later,

Dave P.
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Old 08-28-2010, 04:15 AM
  #99  
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Default B-47 2,3 Engine 'Pod' Strut/Retract

Hi B-47ers!

Will try to post a short video of the 2,3-engine pod/strut retract/lower sequence. Doors are not to scale - just place holders. For this to contraption to work, the retract will have to penetrate one of the exhaust tubes by a small amount, but I don't think it will have much effect on the thrust.

Cheers,

Dave P.

PS: Nuts! guess I don't know how to upload a small video file, so it anyone is interested, drop me an email and maybe I can send it along.
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Old 08-28-2010, 10:16 PM
  #100  
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Default B-47 2,3 Engine 'Pod' Strut/Retract

OK, try the Utube address for the video: http://www.youtube.com/watch?v=UUPFzGTjz3U

Cheers,

Dave P.

Last edited by Capt. Midnight; 08-28-2010 at 10:22 PM. Reason: Correct video address
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