HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 30, 2012, 12:44 PM
Registered User
shadow102's Avatar
United States, GA, Acworth
Joined Mar 2011
4,357 Posts
Discussion
What is it and what does it do?

Hey guys still failry new to the DLG side of this hobby and i am having a blast.

I am looking at purchasing my first brand new DLG and i keep seeing some terms that i am unsure of what it is or what the advantages/disadvantages are:

Disser
D-Box
Spread Tow

All i know is typically these make the glider more expensive but not sure exactly what they do. Thanks
shadow102 is offline Find More Posts by shadow102
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 30, 2012, 12:54 PM
Registered User
United States, AZ, Tucson
Joined Nov 2010
4,077 Posts
First off welcome to DLG! I have seen you in the 3D thread. I too used to only fly 3d, or fast planes, until I caught the DLG bug!

Anyhow, I think I can help.

Disser, is when you see a wing that looks like it is checkered. It is actualy carbon tow (thread) criss-crossing all over the wing. It increases torsional stiffness, therefor launch height. Very little weight penalty.

D-Box, Is when you see the leadiing edge of the entire wing is carbon (the rest might be Fiberglass, or kevlar). The Reason it is called Dbox is because not only is the top and bottom of the leading edge carbon, but it usually ends right at the carbon wing spar. This would create a D shape if you look at the root airfoil from the inside.

corrected...?
Jwmflying14 is offline Find More Posts by Jwmflying14
Last edited by Jwmflying14; Nov 30, 2012 at 01:04 PM.
Reply With Quote
Old Nov 30, 2012, 01:03 PM
Sure it'll work
Flyextreme's Avatar
United States, CA, Torrance
Joined Nov 2005
4,277 Posts
Quote:
Originally Posted by Jwmflying14 View Post

Spread Tow is literally unwoven carbon thread spread out over an entire part etc.
Are you sure about that?
Flyextreme is offline Find More Posts by Flyextreme
Reply With Quote
Old Nov 30, 2012, 01:11 PM
Registered User
United States, AZ, Tucson
Joined Nov 2010
4,077 Posts
Okay, so Spread tow, is literally carbon thread, sometimes woven in a much larger pattern. It is often those wings that have "large" carbon squares, which are the wider spread tow weaves. However, Spread tow can ALSO be carbon thread pulled tight or constructed in a high pressure mold with not much uniform at all. It is kind of a broad term.
Jwmflying14 is offline Find More Posts by Jwmflying14
Reply With Quote
Old Nov 30, 2012, 01:14 PM
Registered User
Thermaln2's Avatar
Reno Nevada
Joined Oct 2007
2,627 Posts
Wow, there is a whole ot of synmantics here that is totally inaccurate. We apply the definitions to carbon, but all the items asked about have been used for decades.

So we have to start from the begining and define things, then we can apply the carbon use or implication..

Chris
Thermaln2 is offline Find More Posts by Thermaln2
Reply With Quote
Old Nov 30, 2012, 01:16 PM
Registered User
Thermaln2's Avatar
Reno Nevada
Joined Oct 2007
2,627 Posts
Jezzz, Spread Tow is NOT carbon thread. Threads are twisted, in general. Spread Tow is composed if Uni-directional fibers that are then woven.
Thermaln2 is offline Find More Posts by Thermaln2
Reply With Quote
Old Nov 30, 2012, 01:36 PM
Registered User
United States, AZ, Tucson
Joined Nov 2010
4,077 Posts
Okay, then I stand corrected. Thanks for the info.
Jwmflying14 is offline Find More Posts by Jwmflying14
Reply With Quote
Old Nov 30, 2012, 02:01 PM
Sure it'll work
Flyextreme's Avatar
United States, CA, Torrance
Joined Nov 2005
4,277 Posts
Quote:
Originally Posted by Jwmflying14 View Post
Okay, then I stand corrected. Thanks for the info.
2 out of 3 ain't bad . I didn't know the "exact" deffinition myself.
Flyextreme is offline Find More Posts by Flyextreme
Reply With Quote
Old Nov 30, 2012, 02:04 PM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,167 Posts
Quote:
Originally Posted by Flyextreme View Post
2 out of 3 ain't bad.
That sounds like it could be a song......
kenh3497 is offline Find More Posts by kenh3497
Reply With Quote
Old Nov 30, 2012, 02:19 PM
Registered User
shadow102's Avatar
United States, GA, Acworth
Joined Mar 2011
4,357 Posts
got it thanks guys

And yes JWM still flying 3d but very much hooked by the DLG and FPV bug
shadow102 is offline Find More Posts by shadow102
Reply With Quote
Old Nov 30, 2012, 02:24 PM
Registered User
Thermaln2's Avatar
Reno Nevada
Joined Oct 2007
2,627 Posts
Shadow102,

All good questions. Most of the time people talk about the three in terms of carbon, but overall each can be considered just some sort of fiber whether is be cellulose (for the balsa junkies), glass fibers, kevlar fibers, or carbon fibers, as well as boron or nylon, or any other materials that can be handled as fiber.

Let's start off with the word Tow. Tow is basically the word used for a bundle of all the fibers aligned in some linear fashion. If you take normal cotton threads, the tread being the single fiber, then tows make up the weave of the fabric. If you bunch together alot of fiber you create a rope, of sorts, or if you put the fibers side by side, you have a thinner flatter alignment.

With carbon, the more fibers the bigger the bundle fibers, so it looks more like a rope, or wire group. Carbon Tow generall is made in quantities of fibers. 1K tow tends to mean 1000 fibers together, 3K = 3000 fibers and 12K = 12,000. If you were to place the 1K tow fibers side by side, flat, it might be 1/8" wide, 3k might be 3/8" and 12K might be 1.5" wide, roughly. As we look at them, when flat, the 1K looks like a thread, but 3K flat looks like tape recorder tape, while 12K looks like perhaps duct tape. Now when you weave them togther, the 1K looks like a fabric, but the 3K and 12 K look more like flat basket weaves, but flat. I think you get the picture.

When we use 1K carbon cloth, apply epoxy, we then roll out the carbon the try to make it flatter and thinner, when we layup wings. With the fabric, even when we flatten the groups of tow, they go over and under, and this over and under weakens the carbon. So to reduce the amount going over and under we take the wider 3K flattened tow and make a fabric out of it. It becomes stronger and 12K extends that further. So really 1K cloth flattened is a spread tow because when we roll out the cloth to flatten it, we are "spreading the tow". Hence the term spread tow.

If we start off with small bundles of tow we can get a thinner skin, and if we can spread the tow out before we weave the carbon, we can also get a thinner skin..

So that is Spread Tow as I can explain it. I'll reply to the others in a minute.

Chris
Thermaln2 is offline Find More Posts by Thermaln2
Last edited by Thermaln2; Nov 30, 2012 at 03:06 PM.
Reply With Quote
Old Nov 30, 2012, 02:30 PM
Registered User
United States, AZ, Tucson
Joined Nov 2010
4,077 Posts
Well that is exactly what was in my head I just couldnt explain it like that! Lol thank you.

Now what do you call tail crpups or even whole wings that are covered with unwoven tow?
Jwmflying14 is offline Find More Posts by Jwmflying14
Reply With Quote
Old Nov 30, 2012, 02:38 PM
Registered User
Thermaln2's Avatar
Reno Nevada
Joined Oct 2007
2,627 Posts
Shadow102,

Disser, in general with carbon, is a combination of fibers, but it is how the fibers look.

First, carbon tow, let's say 1K tow, is thin and linear. If you take any fibric you can count the fibers in the weave. If you replace every 10th fiber, in one direction with a fiber of a different color, the fabric will look ile it has lines in the fabric. Now when you replace the cross fibers the same way, you have a fabric that looks like graph paper, cross-hatched lines.

Now if you have a fabric of kevlar, and replace every fiber, spaced 1" apart with a fiber of carbon, then you will see a fabric of a mustard color (the kevlar) with crossed lines of black carbon. This is what is called Disser Kelvar fabric. Now when you look at the DLG wings you will see the orientation of lines with respect to the wingspan placed ina way so that they are at a 45/45 to the span. This is what we mean by a Disser wing. But the question is why is it oriented that way?

The 45/45 orientation prevents twisting of the wing. But why use disser cloth versus a full carbon skin. The answer to that is basically "Money". Carbon costs more. Another important thing is the thickness of the DLG wing. The thicker the wing, the more resistent to twisting the wing becomes. I think of disser much like the cross and diagonal members of a bridge. You do not need alot of carbonn to get the cross bracing of the carbon fibers to prevent twisting.

If you go back in time you will see balsa winged planes with diagonal cross bracking between the ribs. This does the same thing that the disser CF tow does. So the idea of disser has been around a long time.

How's that?

Chris
Thermaln2 is offline Find More Posts by Thermaln2
Reply With Quote
Old Nov 30, 2012, 02:46 PM
Registered User
shadow102's Avatar
United States, GA, Acworth
Joined Mar 2011
4,357 Posts
cool thanks for the explanations it makes more sense now so i know what i am looking at. Pretty much everything is done to create more stiffness in the wings and tails
shadow102 is offline Find More Posts by shadow102
Reply With Quote
Old Nov 30, 2012, 02:50 PM
Registered User
Thermaln2's Avatar
Reno Nevada
Joined Oct 2007
2,627 Posts
Quote:
Originally Posted by Jwmflying14 View Post
Well that is exactly what was in my head I just couldnt explain it like that! Lol thank you.

Now what do you call tail crpups or even whole wings that are covered with unwoven tow?
Most of the time the builders just say that they layed up the wing using Unidirectional carbon. However, usually the CF layer has some fabric added that gives some strength chord-wise so the fibers don't split.
Thermaln2 is offline Find More Posts by Thermaln2
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Radio telemetry system - what does it actually allow me to do moglos UAV - Unmanned Aerial Vehicles 5 Sep 09, 2012 12:07 PM
Question What does an external crystal do? Dave8888 Multirotor Talk 3 Jun 28, 2012 11:44 AM
Discussion What does the roll/pitch/yaw do for the Mag sensor on Multiwii? signal15 Multirotor Talk 0 Jun 24, 2012 01:55 AM
Discussion What Does an ESC Do and How Does It Do It? -Link Please Murocflyer Power Systems 12 Jun 19, 2009 02:15 PM
Discussion gyro...what is it and what does it do ?? micro_doc Electric Heli Talk 1 Sep 09, 2008 06:39 PM