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Old Jul 13, 2011, 06:36 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Build Log
Scratch build 1/10 SB2C Helldiver 60 in wingspan

A friend at work has really been encouraging me toward composites and with Sparks' book and great builds posted I feel armed and totally psyched out to start my very first scratch build... out of foam. I've always loved the Helldiver. Aside from the Jerry Bates plans (read awesome) there is no other r/c kit that I have been able to find of the "Beast". 60-inch span should be nice and stable and allow me to have something physically able to hold on to and hopefully be a little forgiving to mistakes.

The plan is simple. Solid forming everything and covering with fiberglass. I've been thinking about making the outer wing panels with FFF ribs and covering but I'd like to try the solid method first. Single 1/4 inch ply spar should do the trick for strength and e-tracts since... I already have a pair.

Electric .46 sized motor. Have one but I love that plane so I'll probably get another. Have some servos lying around. I have some fun details in mind but I'll keep them to myself for no so I am not committed. I will be doing a functioning bomb bay with bomb drop. It is after all a dive bomber. Split flaps are a must. So with all that all 8 of my channels are gone.

I've not officially decided which variant I'll go with but more than likely it will be the 4 or 5. The perforated flaps are awesome and I have a little cheat method I plan on using for that.

Please feel free to chime in and suggest and correct. I love to build and enjoy the learning process.
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Old Jul 14, 2011, 08:47 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Got the h-stab joined, sanded, and the balsa spar in place. Glue is drying. I also had to use some lightweight spackle to fill holes made from keeping the airfoil templates in place. Sorry no pics but I am sure you can imagine what it looks like
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Old Jul 16, 2011, 09:01 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Got talking with my friend and he suggested I simply go shorter on my wing section length. If I want to go longer than 18-24 inches he suggested a feather cutter but nothing longer than 24 on that. I've made my template for a mid-wing airfoil and so I need to get those panels cut now. I did manage to get the elevators done today.
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Old Jul 19, 2011, 03:03 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Update

I've had a summer cold and am getting over it but progress is progress. Pic included of the horizontal stabilizer and elevators. Once glassed they will be joined and have an internal control horn in the center. One wing's parts are complete. The other needs one more panel cut. The differences in color you see are due to age. One saw a bit of sun through a garage window and is older stock than the new sheet I've been using as well. I've decided on the dash-4E variant. I like the look of the canopy better than the more unobstructed dash-5. That is really the only visual difference. Different radios and internal tanks in the dash-5 but its all stuff that you would not really know otherwise. This decision led me to having to source a spinner. Already had one so I primed it and painted it the dark blue and gave it a nice clear coat.

Power setup I'm thinking of would be a .46 motor with a 16x12 APC-E prop and a 60A ESC running on a 3S 5000mAh battery. I'm thinking this will work with my target weight of 5-6 lbs. I have plans for this one and it estimates the same weight but suggests a .60 size motor. Any thoughts?
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Old Jul 25, 2011, 10:31 AM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
I've been terribly sick and have not made any building progress. I have been working on research for the markings I will be using. I've decided with VB-82 off the USS Bennington. Specifically I'll be doing serial number 81 assigned to Lt. Com. Hugh Wood Jr. and his crew member Lt. H. H. Reed. From what I can tell he was the first to drob bombs on the attack on the Yamoto. The attached image shows the "double arrow" associated with this group. All references indicate that they did not use the typical tri-color paint but the single dark blue including on the underside of the retracted wings. Makes things easier but not by choice here. I wanted something historically accurate. These images also show no spinner but I know that is false. There is also a lask of the APS-4 radio pod in the images but that will be made short work of with a molded bomb from parflyerplastics. Rockets will be scratched and fixed. The internal bomb will be dropable.

I've been planning where to locate the main wing spar. It will be simple but strong, running the length of the entire wing up to the tips. 1/4 inch ply. I'll make an interlocking bace for the main gear to slip into so that weight is transferred to the spar and not the foam.
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Old Jul 26, 2011, 01:06 AM
Jack of all master of none
splinterz25's Avatar
Baltimore MD USA
Joined Jan 2011
4,189 Posts
hay if you look on top of my LP's you would see my iPod, what can I say I'm old school. I don't want to seem stupid but can't you do the wing core in one piece;I've never worked in foam but that's what I thought you would do, then put carbon fiber rods through for rigidity. good luck with the new build I'll be watching and learning along w/ you maby I'll try one my self.

Bruce
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Old Jul 26, 2011, 05:56 AM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
You can get away with longer cuts if you have a feather cutter but that is limited from what I have heard. Since I do everything by hand its better to do more sections. The kerf from the wire has more front-back and top-bottom sag the longer the wire is. If you are using a mechanical device this can be minimized but since I do it by hand I just make shorter cuts. You will see how I do the spar. CF is nice stuff but for this application a pit overkill for the price. 1/4" ply will be plenty strong and not add so much weight that it will be unflyable.
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Old Jul 29, 2011, 07:47 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
For Bruce

So since Bruce was curious how I am to do my wing and main spar... I give you an update.

Basically I lay out the templates I made from the enlarged 3-view. I find the line I want to make for the main spar. In this case I have settled on the scale location since it is clear of the gear when retracted but also a good point for CG. I Then measured in metric... because I LOVE metric. Got my length. I measured on my templates at the root and tip from the leading edge to where the start of the spar would be. Then I do approximately 2/3 of the length top to bottom. Basically I want the mid point... not the line for the airfoil chord but the other line that follows the curve profile of the airfoil. Once I get that height I mark it on the airfoil templates and measure aft 1/4 inch for the thickness of the spar. Then I cut this notch out of the templates. Then I measure the length of the panels and mark that on the spar. Measure the thickness of the two intermediate rib templates and you have the length of the groove. Place it out on the templates and remove the notch.

I file and sand each carefully before I use the foam bow. Place the templates back on the cut pieces with the bottom toward the top. The nails from the templates should already align from when you cut the airfoil. This then exposes the notches and you can simply cut the groove out with the foam bow. I used a metal file to remove the debris and smooth things out. Its not a final fit but you can tell it fits quite snug. Once the ends of the sections are properly sanded I can glue this together and then the leading edge of the wing can be formed. Still need to do the other wing like this too.
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Old Jul 30, 2011, 05:42 PM
Jack of all master of none
splinterz25's Avatar
Baltimore MD USA
Joined Jan 2011
4,189 Posts
Quote:
Originally Posted by Willsonman View Post
So since Bruce was curious how I am to do my wing and main spar... I give you an update.

Basically I lay out the templates I made from the enlarged 3-view. I find the line I want to make for the main spar. In this case I have settled on the scale location since it is clear of the gear when retracted but also a good point for CG. I Then measured in metric... because I LOVE metric. Got my length. I measured on my templates at the root and tip from the leading edge to where the start of the spar would be. Then I do approximately 2/3 of the length top to bottom. Basically I want the mid point... not the line for the airfoil chord but the other line that follows the curve profile of the airfoil. Once I get that height I mark it on the airfoil templates and measure aft 1/4 inch for the thickness of the spar. Then I cut this notch out of the templates. Then I measure the length of the panels and mark that on the spar. Measure the thickness of the two intermediate rib templates and you have the length of the groove. Place it out on the templates and remove the notch.

I file and sand each carefully before I use the foam bow. Place the templates back on the cut pieces with the bottom toward the top. The nails from the templates should already align from when you cut the airfoil. This then exposes the notches and you can simply cut the groove out with the foam bow. I used a metal file to remove the debris and smooth things out. Its not a final fit but you can tell it fits quite snug. Once the ends of the sections are properly sanded I can glue this together and then the leading edge of the wing can be formed. Still need to do the other wing like this too.
I'm watching; It must be nice having a graphic artist in the house to get all your enlargements done quickly. nice work

Bruce
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Old Jul 30, 2011, 08:09 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Nah, She does my graphics and some other strange requests I get for my planes. I do all my enlargements of things. I often do my own graphic work and she cleans it up. She has this "thing" where we will be out at the store and she will go through and name off the fonts. We just had a Wegman's open in town and we went today and she was doing it again. I love being married to my best friend.

At any rate. I got the grooves gut for the spar in the other wing tonight. Still need to clean up the edges before I glue them in place. I've been working on the bomb bay as well... conceptually. Since the spar will terminate at the bay I have been working on how to inter lock the main spars into the bay walls and have everything be perfect. Since I need to glass the wings before I connect them this makes it challenging.

On a side note... I got everything done I needed to today and a bag of chips too.
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Old Jul 31, 2011, 02:01 PM
Jack of all master of none
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Baltimore MD USA
Joined Jan 2011
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willsonman are you using the same foam for the entire wing it looks to be two colors in the pics? it's coming together nicely.
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Old Jul 31, 2011, 05:29 PM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Its the same type but I'm using up old stock. It is a little exposed to UV but still intact. I'm fairly pleased with things thus far. I think the bomb bay construction is next up while I smooth out the joints for the wings.
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Old Aug 19, 2011, 08:17 AM
Jack of all master of none
splinterz25's Avatar
Baltimore MD USA
Joined Jan 2011
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must be a big honydew list?

Bruce
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Old Aug 19, 2011, 09:54 AM
No Hangar Queens!
Maryland
Joined May 2009
1,661 Posts
Nah... been having a crazy work schedule. From last tuesday to last friday I only slept 9 hours. Odd this week as well and have other projects that are oing on as well.
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Old Aug 26, 2011, 12:12 PM
MULTI ENGINE FANACTIC
CESARNOGUEIRA's Avatar
SAO PAULO,S.P.,BRAZIL
Joined Dec 2000
543 Posts
Beutifull work. A rarely seen rc plane! Congrats!
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