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Old Feb 22, 2012, 09:46 AM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Gree, Welcome

Pasakorn, Welcome. I am happy you are visiting and I hope you stay awhile.

KSmith. Nice to have you along. I am always happy to have a knowlegable person from the land of many flying boats.

I Have got some fuselage turtleback formers in place and made cable mounts for the controls. My next plan later today or tomorrow is to do the sides skin[covering with Depron foam. I plan on using a thin Polyurethane glue for this. I also will put in a reverse angle on the bottom chines to help keep spray down. . I have no pictures today. First being a nice day I am going to get some flying in while the day is good.
**Neons** Bob
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Old Feb 23, 2012, 06:41 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Hull Sheeting

Here is some work I have done so far today. I may go do a little more later. I use 3mm Depron foam skin. I use Elmer's Ultimate polyurethane glue. It does not matter what type glue you use but CA is not for this work. Poly glue is light and very strong. It cures overnight. It can be used without water spray but cures slower. The working time is slow. It allows adjusting the sheet. I also use a big syringe used for baking and to inject the meat with juices as you cook. I ground the needle flat and loaded it with glue. It is perfect for this job. It allows very controlled placement of a glue bead. I like this a lot. It can reach way into the plane and get the glue right where you want it. Look closely at the pictures and you will see the glue gun syringe. Probably can be found in kitchen supply stores.

This Depron foam is the best stuff I have worked with. It scores high in workability. The down side is it is not ding resistant. It will need spackling and 0.75oz glass cloth and a skim of epoxy. Even then I have to be careful. It is very light weight also.

I cut the foan to fit and put it in place like 1 -2 -3. That easy. Did a couple pieces and take a short break . Come back clean up any foam action from the glue and prep another section. About 1.5 hours I pull the pins. When I started the tail section bottom it has a 1/2 round former. This was a little different approach. I cut the sheet to almost fit. I got the edge to be glued straight and a good fit. Then I hot melt glued just the edge. When nice and solid I ran a masking tape along the seam. Then I used the glue gun and gave it beads of glue on all the contact edges. Taped it over the formers and pulled it dowm. Grab a stick and clamps and secure it. Let it dry before doing the other side.

After getting the last sheets on the sides I will be doing the bottom next. I shot a picture inside the hull to show how the sheeting is flat and a smal bead of Poly-U Glue foam action. It bonded very well.

**Neons** Bob
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Old Feb 24, 2012, 02:28 AM
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Trevorh's Avatar
Hampshire, U.K.
Joined Jun 2008
1,881 Posts
An interesting approach - and all new to me!

Thanks for sharing.

Trevor
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Old Feb 24, 2012, 08:41 AM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Trevor,
I have made many planes over the years. This is old school wood framing that I did 50 years ago. Now building this way moves at a snails pace. I could have very easily built the plane like "Emily" with 95% foam sheet and hotwired wings and with glass skin constructon. I decided to use a lot of Depron as I have a box of 30 sheets and want to do something with them. The Depron sheeting is very good but as I mention it will need a glass protecting skin. The wings are going to be similar also with wood framing and foam parts..
Thanks,
**Neons** Bob
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Old Feb 25, 2012, 08:50 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Hull Bottom

I finished closing in the curves on the hull yesterday. had to do it in 3 pieces each side due too the compound curves.The closing plank on the side would be a butt joint all around. I did not like relying on edge glue to support a closing plank. I put in battens to give more strength due to the extra bonding area. Look at the picture and you will see the pieces behind the foam edge. Glued it in and taped it up.

Today I did all the bottom sheeting. It called for 1/32 inch plywood and I did not have enough. I had 5mm Depron sheets that were firm.. I put the bottom glued in place in 6 pieces. . Before gluing, the bottom on each former near the keel has to be notched to allow water to pass (limber holes)without trapping it. The bow had to be pinned, taped, and clamped the get the curves. I set it aside now to dry overnight.. I have a lot of sanding to shape and I want to do the nose and tail blocks next. Right now the plane weighs in at 1lb 13oz. (0.822kg.). Not bad.
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Old Feb 25, 2012, 11:50 PM
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how much's Avatar
United Kingdom, England, Wigan
Joined Jul 2011
756 Posts
nice work Neons.. i was considering building my Sunderland half balsa/half depron as it would have saved quite a bit of time and money (already got a box of depron in the garage) but decided against it and went all balsa due to all my depron models getting knocked dented and creased way too easily.. they all start to look rough around the edges way before their time.

i bet yours is finished and flying before mine though

David
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Old Feb 26, 2012, 09:42 AM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
David Thanks,
You are right about most foam. Most foam is like the softest of balsa and about equivelent. It all goes with how you finish the foam and protect it from damages. I have mostly all foam planes. At least 30 of them. The real good ones are all framed in balsa. The main thing to do on the wing, rudder, and elevators is to have all wood edges all around including the control surface edges. The innards are all foam. These can be glassed with 0.75 oz. cloth and a layer of epoxy. If the plane is not as important use Miniwax clear waterbase polyurethane. It is not as hard but will give some added protections.

The fuselage I am doing will be epoxied with a layer of cloth and maybe 2 layers on the bottom. That will be not to far away. I have finished my last seaplane this way and it is very well resistant to many damages. I think it is almost equal to an all wood construction. I would think if I used all wood I still would have epoxy glassed it anyway. I use all airbrush spray in military flats or semi gloss paint. Repairs are easy for me as the paint matches good for local touchups.
**Neons** Bob
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Old Feb 26, 2012, 01:55 PM
Student of Ivan
mountainman2442's Avatar
El Paso, Illinois
Joined Apr 2006
725 Posts
Bob,

Great subject to model! I've had Ivan's Mars plans since '07 with just this conversion in mind. Knew if I waited long enough, I could watch someone else figure all the hard stuff out...

These props would look great on it by the way.

Looking forward to seeing it come together! Good luck.

John
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Old Feb 26, 2012, 02:47 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Hi John, Thanks.

Well I hope it is done in 3 months. Building stick is slow and I very rarely do this. I am only following the plans as a guide. It is a very light plane to build that way as is obvious in Ivan's movies. Adding foam is a different more modern way for me to build. I have been doing it for about 7 years now. I just happen to like foam. So now we have tradition and a modern mix. I selected this version as I scoured the internet for pictures, books, plans, and other builds of the Mars XPBM-1 &2. No one was found building this version.

Now those props are some of the nicest scale props I have seen local. I am not going that extreme. I am using the 3 blade E-props I have on hand. I may machine the spinner nuts if I can't find them. I am not a too scale fanatic either. If it looks right it must be right. Finding true scale plans just are not out there with limited pictures too. The plans have changes that are not scale but they simulate scale. The front view of the sides on the plans tapers in toward the wing for instance. The actual pictures and 3 views have boxey sides. The step is deeper. The elevator is maybe 20% larger These are examples. It does not matter as it is built to similate, fly, and have fun.

Check some others I built in Vimeo and Youtube by going to my Avatar to get there.
**Neons** Bob
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Old Feb 27, 2012, 12:30 PM
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mvaller00's Avatar
Joined Apr 2011
20 Posts
Wow Bob... Great job so far, this type of thing blows my mind. I heard that you like to build from some of the guys at the Club but this is impressive. I'll be following along as well to see how this goes. (by the way this is Mike from the Boys & Girls Club)

Keep up the great work!
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Old Feb 27, 2012, 01:06 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Hello Mike,
Welcome to RC Groups and to my Build Log. Imagine 2 posts and you end up here with one I will see you next event at the Gym. Nice to have you and to see how the real models used to be built, but with a twist.
Good Day,
**Neons** Bob
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Old Feb 27, 2012, 02:20 PM
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Gree's Avatar
Sydney, Australia
Joined Jun 2006
2,941 Posts
(It weighs 83kg!!?? That's a lot heavier than I am! Think you may mean 83g? )

Looking good so far!
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Old Feb 27, 2012, 03:42 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Hi Gree,
I am happy you point it out as I am not fluent in metrics. i just thought it would be helpful. It is 29 ounces US measure. Lets see if I get it right with my Conversion program. How about 0.822kg. That is what it shows now. I am sorry but I tried. Thanks
**Neons** Bob
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Old Feb 27, 2012, 05:41 PM
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how much's Avatar
United Kingdom, England, Wigan
Joined Jul 2011
756 Posts
Bob
28 grams to the ounce as near as dammit!


David
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Old Feb 29, 2012, 11:22 PM
5,200 Led Lighted Bike-Bob P.
**neons**'s Avatar
USA, MA, Swansea
Joined Mar 2003
2,812 Posts
Nose, Battery, and Access Hatch work.

The work in the past few days needed some thought as where I want my battery. A tray was installed and the hatch was framed. The nose and open cockpit is installed now. I will frame the cockpit windows and finish the hatch cover next. The cockpit floor will be shallow and not much details. The battery is below. I will put another sub floor under the wing also. So much room here.

I have the wing saddle frame to make then cover the turtleback and then I will think about epoxy skinning the fuselage. Sanding and priming soon.

**Neons** Bob
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