jetpack

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I'm waiting for my used K&E drafting machine to get here but in the meantime I want to shop for some scales it is minus of.

The question is what kind of ends on the scales should I look for? I found the kind in the picture for sale and specify they fit K&E, but looking at the machine arms I can't see how they would mount, there's no screw holes???

We had them back in high school but who pays attention at that age?

Would anyone know where to learn about the K&E arm as far as adjusting the bands, tuning it up, etc? I would like to be able to adjust it if it's off.

Villa

Hi jetpack
I'm going back about 50 years. The bracket with the two screws on photo #3 slips into each of the two short arms (at 90 degrees to each other) in photo#2, via a channel type groove that is underneath the view shown. A light tap engages and disengages the ruler. For fine adjustment of the 90 degree right angle, I believe that the bracket with the two screws in photo #3 has some adjustment. I never saw the rest of the mechanism taken apart.

JustPlaneSweet

The bracket fits into a dovetail groove on the back of the L. The bracket is attached to the scale has a flat head screw and a pan head screw. The 90 degree angle between the scales is adjusted by loosening the pan head screw and tweaking the angle. Tighten the screws when the angle is right.

Stan

jetpack

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Perfect guys, thanks.

dhal22

i looked and looked at your photos. i didn't see a cord or a powder switch.[X(]

jetpack

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dhall

It will fit right into the shop I'm building for my rc boats. You would like the king-seely craftsman and delta bench tools I'm restoring. They have cords and switches. Not sure if they are U.L. Listed yet or not being nothing later than the '40's? [8D]

The arm will come in handy for cleaning up templates I've collected for my boats before they get transfered to the nice ribbon striped sepele mahogany that's waiting.

BMatthews

Lordy, this reminds me that I've got a nice Vemco Vtrack machine that I really need to get out and dust off. I sure don't have room for a big draughting board here but in the new place I'm shopping for I hope to be able to set up a big draughting board for laying out drawings and doing some simple mods or additions to already printed plans. Who knows, I may even do a couple of pencil drawings for old time's sake.

dhal22

i'm not hating on you. my dad and my uncle were both engineers. there was always a drafting machine like that in the house. easier to use than autocad.

CoosBayLumber

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Looks to me that you got one of the Civil engineering heads on the drafting machine that was made by K&E (Keifell and Esser). It used the snap on/off bars of differing markings, and used to use some sort of metal twist-em crank to remove the bars. The original barswere made of wood, but the later plastic ones were see-through and a bit more accurate. Most of the banded drafting machines got eliminated when firms began going to the Tee bar drafting machines.

We initially would use a large plastic (office suplied) template to set the two bars in to place at 90 degrees to one another, but most often we used the common 12, 18, and 24, inch long rules on the horizontal only. We would then loosen the clamps, swing the bar, and lock on to another bearing. Draw a line through a point with a sharp pencil, and strike off the distance, then go on to next one. Ink and notes later on.

Looks to me that you got something out of the 1950's or maybe 1960's. For by the 1970's they were using the Tee bar system in the C.E. world as it was more accurate. If you locate an older drafting book, they ought to show the older style inside the pages, for many firms around here used it up into the middle 1970's.


Wm.

Lnewqban

The machines I used had an adjustable counterbalance as an extension of the upper arm.

The schematic shows another way to adjust the bars over the table, by drawing two lines that are perfectly square.

jetpack

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David, I realized you were having fun so I just added to it, thought you might like seeing the other machines. Machine tools aren't as common as they once were around the neighborhood so I don't know how many young people have even seen such things and suprised you knew what the drawing arm was all about.

And your right about being easier than autocad for quite a few things. I learned autocad as it just started being used and now can't even keep up with the software changes. I rather just stick to my trusty No. 4 pencil and plenty of extension lines and get back to the bench without having to "save" or "print". For models, I think I would prefer it even if I had both because if you are designing something it is much easier to sketch out and eyeball for proportions than it is on a screen. That's just all me though.

William it's good to know where to look for the info on the arm with the surveying reference. I'll look more into that for sure because I think K&E is no longer around, or at least what I've seen searching the name for a manual.

Thanks for the setup tips too, the circle method of checking squareness I had long forgot about but rings the bell now! Sure glad you jogged my memory on drawing that one out to check square!

CoosBayLumber

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K&E bought up Leroy Company in the 1950s. Then Post bought up K&E and then they combined with Mutoh of Japan in the 1980's. But, everyone remembers who K&E used to be.

Wm.

CafeenMan

I always wanted a drafting machine but I've never seen one in person. One thing I started to wonder about is how rigid are these things? I mean when you actually put it to use and put some pressure on it wouldn't it be pretty easy to flex the machine enough to be off a couple degrees? Or am I just too heavy-handed?

Lnewqban

Paul,

I believe you could not deviate 0.1 degree even if hanging yourself from the horizontal edge.

I learned manual drafting by using pencils, T-squares and triangles (yes, I am that old), and after some practice, I learned to put pressure on the paper instead of against the instruments.

One simple solution for you could be a parallel straight edge, assembled on a flat medium size table.
These are not expensive, and you can draw parallel lines regardless of the heaviness of your hand; some are also lockable in any position.

Notice that these things have been evolving just to achieve higher productivity from the drafters, rather than to improve the quality and enjoyment of manual drafting.
For example, instead of drawing an angled line with a t-square and a combination of triangles, the machine shown in the first post, allows you to quickly rotate the edges to that angle, and also to work on any position of the table, from horizontal to vertical.

Many engineering marvels were designed using these "rudimentary" instruments.

I work with AutoCAD every day, but I use any opportunity to draw by hand.
I understand that precision of CNC machines is amazing; however, there is something that has been lost for the drafters by the introduction of the smart computers to this trade-art.

Here you have some references:

http://www.tpub.com/content/engineer...s/14069_65.htm

http://www.draftingtables.com/drafti...raightedge.cfm

http://www.daube.ch/docu/glossary/dr...#camera_lucida

BMatthews

Well, I think you're exagerating a little there. The machines were amazingly accurate and stiff when set up well but if you were to lock the slides on the Vtrack style machines or segments for the arm styles and then pull on one of the rules yeah, things would flex somewhat. But it would take a lot more force than a draughtsman would ever consider using to push things out of alignment that way.

CafeenMan

LNEWQBAN - I've been manually drafting for a long time. My table is 36" x 60" with a single pivot that is tight enough not to move on its own but can tilt the table with a good push or pull on the front of the board. I have a mayline which isn't nearly as straight as I'd like it to be but I don't do enough drafting any more to pay the big bucks for a new one. And my borco has a huge bubble that won't go away and annoys me to no end. And I can't keep my cats off the table. Covering with a cloth and making the table vertical is like saying, "here's a piece of cloth for you to pull down and shred."

Somebody here was going to send me a full set of ship's curves but it never happened. I have a set of five that get me by but as you saw on my other thread, I don't have one that will work for a large airfoil.

CoosBayLumber

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Isn't that size of table one of the smaller types? We used to hire some first year draftsman off the street and give them a common interior house door to set up on a pair of sawhorses that was larger than that. Our smaller Vemco tables were usually of the 42" by 80 inch size as did not have room for anything larger. We used Battleship linolium as it was tougher and cheaper than Borco. We used Highway curves out of plastic instead of "Ship's Curves" as they were in stock at local blueprint houses, and ship curves had to be ordered.

The common drafting machine was not used for once you twisted them in going from here to there on the table, the bands stretched and you then lost accuracy.

I dunno, for only began back in the late 1960's but we sure ditched the hand systems once computers became widespread.


Wm.

CafeenMan

The small tables are 2' x 4'. Mine isn't huge by any means. On anything larger than .60 size I have to untape the paper and move it.

By the time I started drafting (early '80s) nobody had anything but French curves so I had to order my ships curves.

I enjoy drafting until I've inked something and it's been dry for ten years and then I need to make a major revision. No eraser in the world takes off old ink without going through the emulsion - not even imbibed erasers. Basically it means tracing the drawing onto new mylar.

jetpack

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I have plans on making my own board out of a hollow core door, just like my main bench is made from, and an N scale train layout before that. Doors work good for me.

I thought about using the back of lenolium. I am not sure about how smooth smooth can be had with either front or back of that material only because as of yet, I've never been an avid lenolium shopper.

I'm just wondering if I should use a light spray of adhesive to plant it, or just double tape the top and let it flap so there won't be any bubbles day to day??? I remember the green/cream color mats on our high school boards but imagine that stuff can cost in a large size.

Ship curves I forgot existed until you mentioned them, and then looked on ebay and seen a vintage wooden box full of them and hovering around $100. They are something that would be almost necessary to get a nice accurate airfoil with especially with my longer hydro hulls that can reach 4ft and all airfoil profile. I'll end up getting to know how wood bends at what size and use the bow method for the guide. It might work out smoother than I could with a template.

CafeenMan

The way I did it was to plot points (or sketch the outline) and then put the stick over the drawing. I would tape quarters to the paper to hold the inside of the curve and tape the ends of the stick. Obviously it took a lot of toying around but if you take your time and are patient it works. The problem is when you have tighter curves than the stick likes.

Now that I have a magnetic building board, I'm going to try it over that instead because taping to paper isn't that secure in the first place. The magnets will hold to the board beneath the paper. Once the curves are drawn I'll take the paper back to the drafting table.

Lnewqban

I see, Paul; you have 200 hours of building ahead of you again!

I believe that lamination will be faster and it will help with the bending around the airfoil shape.

I don’t know what type of airfoil you want to use for this project, the Thwing!’s seems to be symmetrical or may be reflexed.

Using the general dimensions that you have mentioned, I have produced and attached a drawing with three preliminary airfoils selected from Profili, just to give you an idea of the shape and dimensions.

Eppler 168: Max Thickness 12.44% at 26.7% of the chord and Max Camber 0% at 0% of the chord

NACA 0011: Max Thickness 11.00% at 29.7% of the chord and Max Camber 0% at 0% of the chord

Eppler 186: Max Thickness 10.23% at 29.0% of the chord and Max Camber 1.3% at 29.0% of the chord

Once you select one (which can be modified or manipulated as well), I can make PDF files that will print at real scale, in four sheet of paper, letter size.

The front portion should print at full scale (Exterior dimensions of wing-need to subtract skin thickness) in any regular printer; that will help you estimating the curvature of the caps, as well as the sub-leading and the leading edges.

Request to moderators:

This post and the responses below (#22 to #23) do not belong to this thread.
Could you help us with this mistake, and move the last posts from this thread to the thread they belong to?:

http://www.rcuniverse.com/forum/m_9475518/tm.htm

Thank you very much.

CafeenMan

All I really need is the actual airfoil so you've got the right approach. Thwing! as most of my designs has a made-up airfoil. 99.9% of the time I put the thickest point at 1/3 chord. Then I draw light curves until I like it and then darken it enough to see well. Then I paste the original on a piece of plywood, cut it out and lose the original forever because I like to think ahead like that.

I'm having real problems deciding on the wing area. I really don't use large engines so I'm stuck there. I tend to stick to .40 and below. I really like .30 range - large enough to make real airplanes and small enough to have a lot of them.

I plan to use a 3-blade prop only because I want to keep the LG as short as possible.

Looking at a top view, 1,100 to 1,200 inches looks about right but my scaling calculations give me about 1,550 being right.

I've never seen anyone else scale like this but it usually works pretty well.

1 = original model
2 = scaled model

I take the cube root of the engine 1 and engine 2. I divide the result of 2 by the result of 1 That gives me a base ratio. Then I take the square root of wing 1. Multiply that by the engine ratio and square it and there's my new wing area.

So Thwing! had an electric that my buddy told me is about a .21 equivalent.

1.6 ^ 1/3 = 1.1696
.21 ^ 1/3 = .5944

1.1696 / .5944 = 1.9677

Thwing! had a 400 square inch wing.

400 ^ 1/2 = 20

1.9677 * 20 = 39.354

39.354 ^ 2 = 1548.7

Bottom line is I have no idea how much power this engine has. Oh, and I'd like to put dual pipes on it just for the cool factor.

CafeenMan

Forgot my point. Until I know the area I won't know the root chord.

CafeenMan

Attached is more or less how I'm envisioning this rib being built.

CoosBayLumber

My Feedback: (1)

K&E used to market a set of Higway curves in a wooden box for like $100, and I think the Ship curves went for like $200 per box. Then, someone brought out a set of cheaper plastic curves at about 60 the price. And the rush got on.

At, $100 per box for Genuine ship curves then, in a wooden box, then you are getting a (obsolete) bargain. Costs a lot more than $100 to get same curve plotted out via Autocad.


Wm.