I just noticed something that experienced builders have probably known all along. If you build a box-type fuse on a standard side view (for example in the Wylam or Nieto drawings) then the fuse is actually going to be just a little short because the side view doesn't reflect the taper angle of the fuse. It's just basic geometry. On a small drawing this only amount to a couple of millimeters but at 1/6 scale and larger this could come to a centimeter or more difference. And of course a knock on effect could mean that a lot of other little details could also be off.

Do people actually take this into account? Or just say "what the hey!"

Hey, Abu:

Take another look at your estimated difference of "a centimeter" or more. You would have to have an extroadinarily wide fuselage to make that much difference.

Les

Ironically taken to the extreme the old WAR replica man carrying airplanes were built this way and had to have an addenda that the finished airplane would be short by 3 inches, and that he push rods to the tail had to be shortened appropriately.

Les, I was able to measure a 2-3 millimeter difference on the Joself Nieto plans of the Nieuport 11 (which is a little "wide bodied") with about an 18" wingspan so that'd be about 6-9mm shorter on a 60" model. On an 80" model it'd be 8-12mm shorter. Right?

But I suppose for the hassle it's best to just forget such things!

I'm guessing that the Full size plans would call out the dimensions as well as showing the locations. As you know, paper expands and contracts so you need a common reference when constructing the plane. Once this reference is established you can provide the correct dimensions to the stations along the reference line. Having never seen a set of WWI plans in Full Scale I am only hazarding a guess.

As far as I can remember.. most plans have a statement as shown in the attached (any that I have built from)... thats what the top view is for
PS did you get to York ??

Abu.....

Many of the old time model plans used to give a general out line to the fuselage frame. After you built the frame installed the bulkheads, etc. the result would then be as per the plan. The frame was always longer than the complementary in the side view. I seldom see this on modern plans today. I still include this on the plans I do for customers, as it is quite easy to calculate the proper postions for items using Acad. Those of us over fifty know to begin at the frame view, not the side view.

Wm.

Unfortunately, I'm neither an autocad user or over 50 (quite yet). And few 3-views or even structural drawings seem to provide a "frame view" I suppose if this really mattered measurements could be taken from the top view as Donnie suggests and then a new "stetched" side view produced. I don't think I'd bother on a casual scale model but for something built for serious scale competition I'd think this would be necessary. Can a scale judge see that a fuse is 1/4" too short? I don't really know anything about scale competition. Do judges actually get out the calipers?

If I can ever get my computer back from repair, I will have to play with that in Acad, and see. I don't remember having problems in the past.

Les

I'm in agreement with Biggles, to a degree. If you look at the side view of the plan, the length is accurate through the centerline (what in medical parlance would be the midsagittal plane), and you would have to cut a piece (say, a longeron) that tapers from the outer edge toward the centerline longer than the dimension showed on the side view in order for it to be the correct length. This length could be determined from the top view, unless this longeron also was at an angle relative to the plane of the top view also. If so, the plans should state the length of the piece in question, sinc it is not planar in any of the three views.

Take the example of a rectangular solid which is square in its third dimension. Take a point at one corner and draw a diagonal to a point at the opposite end of the rectangle and the opposite corner of the square. This diagonal is not planar in either the side or top view, and its actual length cannot be measured from either view (or from the third view, either). This is the situation you have with the tapered fuselage edges, but your situation is even more complex because the fuse is an irregular shape, and the mathematics to figure the true length is also more complex. See figure below:

The NEED for "True-View" fuselage side view construction on a plans set...and a "CAD-way" of doing it!

Dear Abufletcher:

The PIPE Here yet AGAIN...and this EXACT issue is why I ALWAYS make up a "True-View" drawing on ANY of my CAD plan sets for for ALL those WW I aircraft I've been, and WILL be working on!!!

I've done EXACTLY this for my first WW I RC Giant Scale plans set that I'll be building from, the one for the Bristol Scout C !!

With me looking once more, here on my PC, at the Windsock Datafile No.44 structural drawing, that I've traced the fuselage structure within the DesignCAD 3000's drawing screen, WHAT I did was to first exactly trace the "orthogonal" side view (right angle side view, as seen from right angles TOWARDS the fuselage side)...then, using the TOP view of the fuselage structure on that drawing, I carefully drew a CURVED line along the center of the fuselage longeron where it curves, from one fuselage crossmember aft to the one behind it. It is VERY important to ONLY draw the curve to a "one bay" length, aftwards from one crossmember's center to the one behind it, and use a SERIES of "one-bay-long" curves, with the forward point of one exactly co-inciding with the one in front of it, to get the idea behind the next step.

After I complete that aforementioned "orthogonal" tracing of the entire set of outlines for each and every structural member IN that structural side view, I COPY it and paste an exact copy of that drawing to one side, to edit later into a "True-View" drawing, to build the actual fuselage side over on the CAD plans that I'm creating.

Now, using the cursor to select ONE particular curve segment, I can, while in DesignCAD, use a "Control-I" keystroke combo to bring up the information box FOR that curve...which includes the LENGTH of the curve ALONG ITS LENGTH. I note THAT length down, with Windows Notepad, and THEN use the "Angle & Distance Between Points" command (in AutoCAD it's called the "Distance" command) in DC to get the "orthogonal" SIDE view plan drawing's distance between those same TWO crossmembers that the curve I just measured spans. I then use the Windows Calculator to figure the difference in length between the curve, and the straight distance of that same fuselage bay the curve spans, and use the "Stretch" CAD command, on the "second copy" of the fuselage drawing I mentioned creating in my fourth paragraph of this post, to LENGTHEN the fuselage structural bay that the curve I measured covers...by EXACTLY the difference between the curve and straight line distances.

The Bristol Scout's fuselage has SIX fuselage structural bays that have the horizontal curve in them as seen from a top view, behind the cockpit, and the differences...since I've been drawing the Scout C plans as if they were for a FULL SIZE Bristol Scout, to get in and fly myself (this IS very easy to do in a CAD sofware program!)...range from 0.024 inches upwards to 0.465 inches. [This IS a British subject aircraft I'm drawing up, from 1914, when the UK WAS a fully "feet'n'inches" nation!] The total difference in distance for a fullsize Scout fuse between the "curved" distance along the longerons' horizontal curve, and the "straight, orthogonal" distance adds up to some 26-3/4 inches (67.98 cm)...for a MODEL in quarter sized RC Giant Scale form, this amounts to a 6-11/16 inch (or 17 cm) difference in length...it IS something to be CONCERNED about !!!

Before the days of CAD software, there were really no "easy-to-use" tools available to the RC Scale aeromodeler to figure all this out...thankfully, DesignCAD's latest release (at http://www.imsisoft.com/prodinfo.asp?t=1&mcid=190 ) IS only US $90.00 to purchase before postage (and it certainly is NOT the only "affordable" CAD software package that can do all this for us)...and, with the right techniques, and hardware to bring a scanned scale structural drawing into a CAD program's drawing screen, a "true-view" model aircraft fuselage drawing CAN be created, that will AVOID the "too short" problem entirely.

Very sorry for being a bit "long" with this post...but it DOES take a somewhat carefully thought-out process to make up a construction drawing to create the "true-view" side view drawing that more of us RC Scale builders WISHED we could have...and now, thanks to CAD software and home computers, it CAN be much more easily drawn up these days.

Yours Sincerely,

The PIPE!

Pipe, being a whole 6" short would indeed be a serious fault! I'm really impressed by all you folks who can use CAD -- the closest I've come is playing around with LegoCAD with my kids!

Still I can't help imagining the perplexed look of a WWI era factory worker as we attempt to explain the need to do a computer-generated frame view before we start work!

I took a look at an old plan I did two years ago for a customer that had the frame type of construction.

The length on centerline was 44.10" long.
The length of the 3/8" square balsa forming the sides and running end to end was 44.30" long.

That is better than a 3/16" difference in the long way around as compared to what is simply shown in the sideview. This is why older draftmen used to draw out the frame for building purposes which translated to correct lengths when shown in the sideview. A simple reason for including a frame drawing on a plan.

The old routine was to build the frame on the plan, then build a second one directly on top of it to ensure any errors were then equal. Afterwhich the builder moved them over to the top view and constructed the top and bottom. Next the semi-circular items got added on, etc.

Is there a shortcut to this?

Wm.

I have released a few kits and always just show the dead-on side view on my layout drawings but then these fuselages are lasercut liteply so the drawing is strickly for reference. If I were designing a stick fuselage where the customer is building over the plans then it would be automatic to provide a true view or "frame view".
My wings ARE built up over the plans so there I always draw them in true view. This does create some confusion on the centerline rib which, due to diheadral, is slightly tilted.
Allan

Well now that I've enlarged the drawings for the Nieuport 11 I can actually measure the top view vs. side view and at at scale of between 1/5 and 1/6 (1/5.6) these is nearly a 3/8" discrepancy.

How did draftsmen make frame views back in the days before CAD software? I'm thinking I'll just push each of the verticals aft of the cockpit back 1/16" -- hardly precise but it's better than nothing. Funny how this LOOKS like such a big model ON PAPER. But measured it's only got a 52" wingspan (top) and the fuse (minus the cowl) is about 30" long.

Of course of the Japanese at the flying field thing this is going to be HUGE!