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T-28 Dave Platt

Old 02-18-2014, 04:37 PM
  #476  
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Boyd,
Thanks for the info, still wondering why the flaps are higher than the wing extension. but you were right I don't see any panels lines in the photo
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Old 02-19-2014, 05:17 AM
  #477  
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Larry,

Not sure what you did. You may want to think about taking the top skin off, and sand down the flap ribs (what a hassle) or place the hinges lower. Not sure how that would look.

Boyd
Old 02-19-2014, 05:21 AM
  #478  
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Thanks Hircflyer.

I have a real T-28 here that can be used for a reference point. The wing in Larry's pix is the one I'm speaking of.

What a state to live in. Tropical paradise.

Boyd.
Old 02-19-2014, 05:49 AM
  #479  
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Boyd,
Will take photos tonight and post. The strange thing is that the flaps and ailerons match up perfectly...... and that's why I'm taking up knitting
Old 02-19-2014, 07:26 AM
  #480  
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Larry, you may already know this, but if you buy a quality plastic kit like Tamiya of the T-28 you will have something to go by for all lap seams, panel lines, and inspection panel detail.

It appears there is a misunderstanding on "panel lines". Looking at the photo you will see rivet rows where the leading edge skin panels secure to the upper flap and aileron skins. Look closer and you can see the overlap of these skins. These are referred to as panel lines. Also notice all laps ("panel lines") are made so water will stream over them to prevent water from entering the structure.

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Old 02-19-2014, 07:59 AM
  #481  
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A couple more examples are shown here. The first photo shows an aft lower fuselage panel removed. You can see the row of rivets running forward and aft just above the removed structure. Notice the skin overlap here is assembled over the lower skin. This prevents water from entering as it would if the lap was the other way around. Notice the step at this rivet row. This is a panel line.

The second photo you can see the seam where the fuselage structure is joined together. Look at the vertical line between the open panel and the paper taped to the fuselage. This is a production joint. These two sections of the fuselage could have been, and most likely were built in seperate fixtures and joined together later. This to is a panel line.

Basiclly the only way to not have panel lines on a plane is, the plane would require wrapping with one complete skin.


I hope this helps to define panel lines as we call them. In full scale sheetmetal talk we normally just say lap seams.
Old 02-19-2014, 12:52 PM
  #482  
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Boeing calls them LAP Joints thats what came loose on the Aloha 737 that lost a large portion of its top
Old 02-19-2014, 01:42 PM
  #483  
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Absolutely correct Hircflyer, when I was working as a sheetmetal tech in the air carrier world, we were required to modify the structure due to that failure. When the engineers designed the fuselages there was one continues lap joint (seam) that ran forward and aft tying all the skins together. They did not envision the elements that led to this failure when designing the structure.

When the crack propagated and failed there was nothing to stop the full length of the lap to open like a zipper. Following this tear straps were added. They were additional structures added perpendicular to the joints. Now if a lap joint tried to unzip the tear strap prevented it from unzipping the full length of the skin panel.

Does this make everyone feel better about flying now?
Old 02-19-2014, 02:06 PM
  #484  
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I was in the FAA at thus and I had to inspect each installation of the straps as thet were completed. Since retired
Old 02-19-2014, 03:07 PM
  #485  
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Did you know Jim Hein? I am an FAA Airworthiness ASI myself. What a small world.
Old 02-19-2014, 03:31 PM
  #486  
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... dot .. dot .. Just in, a photo of Maser working on his L-4.

Old 02-19-2014, 04:02 PM
  #487  
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Hi guys,
Warbird, thanks for the info and the photos, I will check out the Tamiya kit.
So good news bad news, what I thought was extremely careful gluing in the hinges and making sure the surfaces didn't move it looks like they did.
Left side of the wing not so bad but the right hand side is terrible.
Tomorrow night I will start cutting out the hinges in the wing and reset them to the proper position.... does it ever get any easier?
Boyd, nice work on the L-4
Okay back to the drawing board. On the bright side the WRAM show is this weekend and there is a chance I can get a new wing kit from Larry Katona of Precision and start from scratch
Though I'm hoping the plastic surgery works

Again guys thanks for the input, it's greatly appreciated

Larry
Old 02-19-2014, 04:12 PM
  #488  
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Best all time flying buddy....he is now in Vegas
Old 02-19-2014, 04:40 PM
  #489  
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Yes he is. He was my HI brother till he moved to the main land, now he is my NV brother. We have been friends for years, and when he travels to OKC I always tried to get him on the transmitter. He helped me cover my Steerman while here one year. What a great guy.

Okay, back to T-28s.

Larry, if you need any photos of the T-28 just ask. I am at the museum all the time.
Old 02-20-2014, 04:19 PM
  #490  
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Hi guys,
Warbird, thanks for the offer, I think I will order a model of the T28 as you suggested.
Started the surgery tonight, see attached pix.
So Boyd the question is how did you keep the hinges from moving while the epoxy set? I thought I had the method but obviously from the surgery that is taking place that wasn't the case.
Also I would assume that you used a straight edge to get the continuation from the top of the wing to the top of the flap...


Anyone please feel free to jump in with a life preserver

Thanks
Larry
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Old 02-26-2014, 05:06 AM
  #491  
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Larry,

When I put my hinges in I made sure the flap/aileron were connected at the time to keep them from slipping. I also made sure they were connected to the ribs in some way.

BTW, it looks like your tubing is to close to where the wheel will fit in the wheel well. Say that 3 times fast. I put mine against the spar. Be sure to double check this.

Looking good. Keep the pix's coming.

Thanks Steve and Hircflyer. I really did not notice the panel lines before. Maybe because I knew it would add to the detail time.

Larry if you decide not to include the panel lines I will understand. It still looks good with just the rivets.

Boyd.

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Old 02-26-2014, 05:27 AM
  #492  
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Yes it does!!

I can't wait to fly it. This way Boyd you can sit and relax and see how good it looks in the air too.
Old 02-26-2014, 05:38 AM
  #493  
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Steve,

The L-4 of course.

Boyd
Old 02-26-2014, 04:00 PM
  #494  
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Boyd,
Thanks for the info, one other question. How did you keep everything from moving until the glue set.

Ran home from work to check the wheel, it clears by about 1/8" on the inboard side of the wheel and I'm sure when the belly pan is done all will be right with the world.

Not sure about the panel lines, there are just too many schools of thought about how to do them

Will post some pix next week after I finish the major surgery.

Thanks again
Larry
Old 02-27-2014, 04:36 AM
  #495  
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Larry,

I kept them from moving by placing cloths pins or equivalent on them. I used 5 minute epoxy.

Boyd.
Old 03-26-2014, 02:48 PM
  #496  
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Hey Gang,
It's been awhile so I figured I would post a couple of pix as to where I am.
Got the ails and flaps out and the hinges cleaned up, waiting for a friend of mine to get some time to help me reattach both, I would rather not go through the surgery again.
On a happier note, I got a Futaba 14SG for my BD, can't wait for it to arrive.... 1st plane to get hooked up will be the Avenger
Hope everyone is dealing okay with the horrible winter/spring, 45+ MPH winds today, calling for 50's and rain Fri - Sunday

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Old 03-28-2014, 02:54 PM
  #497  
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Larry,

Just remember, "The wind is my friend" Ha!

Keep the pic's coming.

Boyd.
Old 04-03-2014, 04:26 PM
  #498  
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Hey guys,
Progress, ailerons and flaps redone and in perfect position in relationship to the wing
No here's the dumbest question I have posted.
If you look at the photos you will notice that the extension off the wing for the flaps is now short due to my previous screw up.
So the question is, do I build up the leading edge of the flaps or do I just extend the balsa to meet the leading edge.
Once I take care of this latest foible I can sheet the rest and think about starting the fuselage. The largest gap is about 3/8" down to 1/8"

Larry
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Old 04-04-2014, 03:06 AM
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Larry

I'd extend the balsa to meet the leading edge. This would be the easiest.

Boyd.
Old 04-04-2014, 01:20 PM
  #500  
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I would inlay some thin G10 or plywood to seal up the gap.

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