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Very Hot Topic (More than 25 Replies) Marcoux Bromberg (Read 18219 times)
Kerak
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Re: Marcoux Bromberg
Reply #45 - Feb 11th, 2019 at 1:22pm
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Is that a "T-6" or a Harvard?  Wink Cheesy Grin

Neal
  
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Re: Marcoux Bromberg
Reply #44 - Feb 11th, 2019 at 1:03pm
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Mike,
We're very interested in a detailed walk around photos of the T-6.  I'll PM my email and when you have them together you can email them to me. We're looking for detail in scale of all aspects of the aircraft.  As you've seen in Gary's photos!
  

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Re: Marcoux Bromberg
Reply #43 - Feb 11th, 2019 at 8:36am
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Well Mike...to my untrained eye...looks awesome and involved.  I wouldn't know if you were "right or wrong."  Simple put, all of this is beyond my pay grade.

I do admire your effort and determination. Smiley

Neal
  
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Re: Marcoux Bromberg
Reply #42 - Feb 10th, 2019 at 6:18am
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Gary - I'm not sure the Marcoux Bromberg had that type of hinge but the existing drawings show no external device for hinging so, since there are no other drawings to draw from, I chose a similar airplane to look at for details and the AT6 is also one of my favorite planes anyway so the research is fun and the plane is easy to get to. The end result will be that this rendition will be the aircraft of record, at least until another more definitive rendition shows up.

To the archives, I have several pics of the AT6 and can take more any time. Here's a pic of my favorite of the two in the Historic hanger and a bit for the Pratt and Whitney crowd. Tom, if this is OK with you, let me know and I can begin getting more detailed photos.
Mike
« Last Edit: Feb 10th, 2019 at 7:34am by New Builder »  

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"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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Re: Marcoux Bromberg
Reply #41 - Feb 9th, 2019 at 11:32pm
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Wow, had no idea that the Marcoux had those types of hinges.  Looks really beefy.  You really took some very good shots of the tail feathers to the T-6/Havard.  Ever thought of submitting the detailed photos to the S&T's archives?  They're really good!

  
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Re: Marcoux Bromberg
Reply #40 - Feb 9th, 2019 at 1:48pm
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Hi Gary - The strap-looking part (#1) is actually a sheet metal cover over the hinge adjusting/mount area. Looking at the horizontal stabilizer/elevator assembly drawings, there are notches in the elevator and looking at the stab portion, there are several pieces annotated that fit into the notches and are the actual hinge that reach through to the torque tube inside and find a mating part there. The notches themselves are the clearance for the hinge as the elevator moves. The actuating part is attached to the torque tube and is cable actuated. I added a photo from the area of the cover.

As to not wrapping the leading edge, I plan on using some stick and tissue methods. The elevators will be framed up, sanded to shape, the hinges installed and a 1/32 sheet ironed on both sides. The leading edge will be a solid piece with the notches in place and just glued to the frame/sheeting and the same with the stab.
Mike
  

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"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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Re: Marcoux Bromberg
Reply #39 - Feb 9th, 2019 at 11:32am
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From what I see in the detailed drawings of the T-6, the illustration that has a number 1 will serve as the strap linking the stab and the elevator.  Looks very nice and impressive!  Glad you have unfetted access to the T-6s.  I must've studied just those detailed drawings for at least half hour just to appreciate what you're shooting for.  Good job! 

It was mentioned you have no intention of wrapping the leading edges around the rudder and stab.  I would imagine you're still covering with 1/32nd ply?  If so, it would suggest you're going to butt it against the leading edges? 

If so, that's my plan too, only I'm using glossy paper instead of plywood. The paper will butt against the leading edges but I will allow the foil that's on top of the paper to continue over the butt joint and the foil itself will wrap around the leading edges of the wing/tail feathers.

Gary (Skye)
  
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Re: Marcoux Bromberg
Reply #38 - Feb 8th, 2019 at 10:03am
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Quote:
the strap will serve as a link between the stab and elevator.  Correct?

Hi Gary - That's correct, at least that version and as it turns out it is not correct in its application either. I have been using the North American AT6 as a guideline for the flying surface connections since it looks for all intents and purposes much like the control surfaces of the Marcoux Bromberg. Since I have unfettered access to the Canadian Historic Hanger near me and they have two AT6s, I stopped by the other day to pay my dues and take a few pics. The pictures don't show enough detail of the inner workings of the rudder, horizontal stab and the ailerons, I was no further along than before. So yesterday I sat down to my computer and looked for a cutaway of an AT6 and found some very good drawings of how it actually works. It's a parts catalog from a dealer and their drawings are probably manufacturers drawings. Needless to say I now have a plan in place to go forward with all the control surfaces and their actuation methodology. All I need to do is miniaturize this plan and should be home free, ...sorta. I have no intention of wrapping the leading edge of the rudder or horizontal stab as shown in the drawings since there is nothing going on there but the hinge mechanism is pretty straight forward for both so will work on them while I continue drafting the wing layout and the ribs to incorporate the aileron detail. Will start cutting and laying wood for the rudder and horizontal stabilizer after I make a couple of sketches to incorporate the real thing into a wood replica. More soon.
Mike

« Last Edit: Feb 8th, 2019 at 12:13pm by New Builder »  

"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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Re: Marcoux Bromberg
Reply #37 - Feb 7th, 2019 at 9:08pm
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Very nicrely detailed.  Had to review your photos and text a few times to get what you were trying to shoot for.  Very nicely done.  As I understand it, the strap will serve as a link between the stab and elevator.  Correct?
  
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Re: Marcoux Bromberg
Reply #36 - Feb 5th, 2019 at 8:28am
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Been working on the horizontal stabilizer while waiting to get to the print shop, can start the wing ribs and spars tomorrow after copies are done. The horizontal stab has some intricacies to be worked out. Wanted to develop a hinge method that will allow the elevator to be actuated. Started with round reed for the outline and added 1/16 material for internal structure then material on each side and sand to profile. Ironed on the 1/32 cover and all worked well except could not sand to right profile and could not wrap it around the leading edge so went to plan B. This is the same as the very first horizontal stab I did way back with frame, material top and bottom, sanded to shape, cover ironed on and leading and trailing edge added and sanded to profile. The change here is the trailing edge is round reed and has aluminum  rings added to use as part of the hinge detail. The elevator will have matching rings and they will be joined with small strap and hopefully be the solution, time will tell. Also added our temperature conversion document for reference.
Mike
  

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"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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Re: Marcoux Bromberg
Reply #35 - Jan 28th, 2019 at 8:04am
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Gary - Detailing the wing should be fairly straight forward since it is all wood, ribs and spars. The spars will have a bit of color as they were laminated black walnut and that native color is pretty simple to reproduce with some of the wood dyes I have in my wood shop. The ribs are pretty standard fare with the usual light yellow-tan appearance. The wing covering was mahogany plywood with a fabric overlay. I will not attempt the fabric overlay since the original was doped in place and the weave would be nearly invisible but will probably use a black tissue overlay after filling and sanding the balsa sheeting since the wing is black on the original. The wing will be mostly open near the fuselage to show the landing gear retracts and related mechanisms. Also to show the aileron torque tube connection to the cockpit controls. The fuselage is another animal all together. It was aluminum bulkheads with aluminum tube stringers and the aluminum skin was riveted to them with a clever device that is well documented in the three views. The thickness of the fuselage skin is unknown, but if it was 3/32 (.093) the model thickness would be .008 and if the skin was 1/8 (.125) the model thickness would be .010 or about the thickness of two pages of standard bond paper. The three views seem to show individual panels riveted to the tube stringers and the space of the rivets is 3/4 inch and in my scale is .0625 (1/16"). Possible to replicate with a pounce wheel if I can find one with that coarse of pitch, maybe a fine pitch and modify it by eliminating the appropriate teeth. Have not gotten to the fuselage detail in any depth as yet but is in my mind. The thickness of the fuselage skin is possible to replicate by sanding down a 1/32" sheet to the right thickness but very difficult to handle but not impossible. Add the detail of the rivets and the whole thing may look more distracting. Plan is to cover the fuselage from the cockpit back since nothing too important is there but leave an area around the cockpit open to visualize the controls. Possibly an area open to show the fuel tank and either part of the cowl open to see the engine and perhaps some of the engine mounting brackets. This is a big undertaking and will require some serious trial and error work to get it done but it looks like a long couple of months until spring so why not.

Have not heard back from the New England Air Museum but am confident they will reply. They are having their share of brutal weather and am sure the museum is closed for some time.
Mike
  

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Re: Marcoux Bromberg
Reply #34 - Jan 27th, 2019 at 10:49pm
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Mike,

Looking good, my friend.  I'll be watching your build with interest.  How are you going to detail the fuselage/wings?  Panel lines and simulated rivets?
  
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Re: Marcoux Bromberg
Reply #33 - Jan 27th, 2019 at 11:28am
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The drafting has about come to the point I needed to get a copy of the layouts and some scans of the ribs. Started out yesterday with some other errands but at 12 degrees and wind chill at -15 degrees, cut the trip short. So today, after shoveling three inches of snow off the driveway,  started assembly of the horizontal stab. There's not much detail to be had here so am experimenting with round reed for the leading and trailing edge. First pic is looking like a standard lamination process except it is one round reed soaked in water and pinned down. Second pic shows a little spring back but nothing major. Third and fourth pics are adding thickness and beginning sanding. This is a departure from the usual 1/16th frame, sanding to shape, sheeting, adding leading and trailing edge and tips since I wanted the trailing edge to be round to match the elevator and create the hinges as seen on the aircraft. I may need to do that anyway if the reeding proves too difficult to cover with the 1/32 sheet. Better days ahead for getting the copies made so will be concentrating here except it's make a snack and off to watch the pro bowl..
Mike

PS
There will be more interesting pics very soon. Will be starting the wing next week with all the ribs and spars.
  

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"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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Re: Marcoux Bromberg
Reply #32 - Jan 21st, 2019 at 11:51pm
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Wow!  That's a great reference source, Tom.  Really has a lot of detailed close ups.
  
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Re: Marcoux Bromberg
Reply #31 - Jan 21st, 2019 at 7:17am
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Tom - Thank you for the reference and yes, have seen the site and am starting a mail conversation with them to see if they have any other pictures, specifically the cockpit and the flap actuating arrangement. All of this detail gets lost to time so I need to get inventive with the methodology. Fortunately my time in aerospace and some related adventures has given me a good background in design details and how things work, just takes some time to work through the minutia. Fortunately, got a lot of time and my trusty drawing board.
Mike
  

"Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts for which the performer is yet poorly prepared." Wilbur Wright
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