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Dan Palmer B-24 plan question

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Old 06-29-2012, 11:39 AM
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Scratchie
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Default Dan Palmer B-24 plan question

I really don’t have much of a problem reading/understanding the B-24 plans, but here’s a dumb question.The pic below is ½ of a fuse former.It’s clear where top and bottom keels go and where spars running the length of the fuse are put.But what about those “spacers holding the spars in place? It seems to me that using these spacers to “elevate” the fuse spars is a good way to build in error.Am I reading this right?
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Old 06-29-2012, 11:49 AM
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Default RE: Dan Palmer B-24 plan question

Just for your information the pieces which run front to back in the fuselage are called longerons not spars. Those pieces you mention are not supports, but rather spreaders, that go across the width of the fuselage to add strength. They are just showing these in relation to the formers and longerons in the drawing, typically they are installed after the fuselage halves have been joined or during the process.
One recommendation I will make is to read the instructions through in their entirety several times before you start your build so you have a good idea of the process.
This advice comes from someone who typically would never read the instructions before building, and got bit by it several times.
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Old 06-29-2012, 12:21 PM
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Default RE: Dan Palmer B-24 plan question

Without knowing the exact construction sequence for the Palmer B-24 it's hard to give any advice on how to proceed but, as noted above, those cross members are there to add rigidity to the fuselage structure and need to be there. There should not be a problem with building the fuselage structure first and then adding these cross members once the basic framework is completed if you believe it is easier and more accurate to proceed that way. I would simply suggest some sort of jig or fixture be used to hold the fuselage in proper alignment while adding them. My .02 cents of course. Good luck!

PS - Check and double check all measurements before proceeding. Palmer plans are notorious for having errors.
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Old 06-29-2012, 01:18 PM
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Default RE: Dan Palmer B-24 plan question

Chad your right about the errors in some plans, and sometimes you only find that that said error as you start assembly of parts you have already fabricated I am glad you mentioned that.

This plane is very similar to Guillow's kits and several other designers where you pin the top and bottom keels over their locations on the plans (protected by a sheet of plastic of course) and then glue your formers in place vertically over each of their locations. After the glue has dried and the formers are securely attached, you install your longerons making sure to square the top edge of the formers to the plan to correct any misalignment (clamping or pining as you wish) to keep everything in alignment. Typically after adding any other lengthwise members the plans or design calls for you join the fuselage halves using either a straightedge line or laser to make sure you have the center-line of the fuselage perfectly straight. It is at this point you add your members that go from side to side for bracing mounts and alike, now this will vary a bit from design to design but is pretty typical for old time plans such as this one.

Scratchy if your new to building I would recommend you take a look at http://www.airfieldmodels.com, Paul has many tips for builders on his site you will find very helpful, as well as this forum there are a lot of guys here that have built some of these planes back when the plans were new. lol
One hint always dry fit every thing first, it's a lot easier fixing something before glue is all over it.
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Old 06-30-2012, 07:01 AM
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Default RE: Dan Palmer B-24 plan question

i've built quite a few planes, this is the first one using plans only without instructions.
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Old 06-30-2012, 07:38 AM
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Default RE: Dan Palmer B-24 plan question

Well that can be quite an experience.
Hopefully my explanation of how to proceed is helpful to you. Just building from plans can be difficult, you will find your first builds like this a bit challenging.
When you start designing you own and building, it gets even more entertaining.
Just keep in mind often with these older design they use sectional views and don't tell you that piece is actually larger, it is assumed you already know that like your question about the spreaders. It doesn't help that he used a center line and did not include the zig-zag break line on the spreaders. So watch for that on other portions...
Good luck with the build you should have a nice airplane when your done.

Here is how it should have been done...
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Old 07-01-2012, 05:30 PM
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Default RE: Dan Palmer B-24 plan question



thanks iron eagle, what you described is exactly how I was going to proceed. Someone once told me there is nothing made of wood that can't be fixed, so as soon as I finish my current project I'm going to start this B-24. I’ll be studying the plans for quite a while, then I’ll cut it myself.

Having built all my rc from kits, and only static from plans.Before the build I was going to study a set of Ziroli D-18 plans and see how he does things, mostly wing connections, elevator and rudder assembly/control.

Attached is my most recent static build (50%, stage prop just before it was finished) – built from blow up 8 1/2”x11” plans from RC Universe.I’ll probably be posting more pre-build questions once I start digging into wing/stab incidence.I also want to ask just how much lightening I can do to the airframe, is it unrealistic that I can build a B-24 into an easy flying, lazy big fat bomber?Wing loading 35oz/ft^2?
Thanks
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Old 07-02-2012, 07:13 AM
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Default RE: Dan Palmer B-24 plan question

Very nice job on the plane!
Dependent upon how you power it IC vs Electric is one question as far as making it lighter, the electric version you can remove a lot more material were you don't have vibration from the engines to deal with. Regardless in most designs you can find a lot of areas to lighten it up, formers, ribs, firewalls and alike can have a substantial amount of lighting holes put in them. And given the vintage of the design, there are probably some areas you can use new methods of construction and reduce the weight even more. Also substituting some composites and other new materials you can dramatically reduce the weight of some of the components as well.
I would think a target weight of 20oz/ft would be your goal if you want it to be a real nice airplane to fly.
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Old 07-02-2012, 08:20 AM
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Default RE: Dan Palmer B-24 plan question

When it gets time to cutting parts maybe I'll check back in. 20oz/ft would be fantastic, but Idon't think Ican estimate any weights until after Icut a short kit for it.. btw, I am seriously looking into electric.
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Old 07-03-2012, 04:09 PM
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Default RE: Dan Palmer B-24 plan question

Without knowing much about the rest of the design it looks like a box frame fuse that is built first, then the top and bottom are added later once the box frame is straight. Could be wrong though.
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