Re: Is Kevlar Honeycomb allowed?
 

The materials for wet lay up or vacuum injection composite construction are available from many vendors. Amine epoxy resins are available from many vendors. There are many vendors that sell fiberglass, S2, Kevlar and carbon woven and unidirectional dry cloth. All the materials to do vacuum bagging are available from many vendors to any team. I can order small quantities of core materials, raw honeycomb and corrugated core materials. McMaster sells pultrusions along with several other companies. These materials are available to all teams and can fit into the cost constraints. If any team wants to do wet lay up I can list many, many links to vendors that would be happy to help out a FIRST team do composites. However with prepegs and other manufactured composites that are used in aerospace manufacturing, I can contend that these materials are not available to all teams and with order $ and quantity minimums are not available to all teams. Give me a name of a company that I can order some honey comb material and meet the FIRST guide lines and I'll change my mind. Last year our team wanted to use honey comb material for our ramps. I could not find a source that met the requirements so we used polycarbonate and had weight problems. Would have loved to use this stuff. May be I didn't search hard enough. Find some vendors and prove that it's a valid material.

Re: Is Kevlar Honeycomb allowed?
 

that stuff is great we used last year as the platform of our ramp because the wieght to strength ratio was exlent but it costs alot like $500 a sheet

Re: Is Kevlar Honeycomb allowed?
 

I can assure you we spent a lot less than $500.00/sheet. I arranged the purchase about April last year, I have receipts and I pretty sure the cost was closer to $320.00 per sheet.

But it is only 3mm thickness. I think there is a mix of RC model Airplanes, Aerospace and Boat building here, everybody is used to different thickness for their applications. My problem with most vendors is, they rape you on the cost of these materials and/or the lead times are to great to make it a viable option this late in the game.

What I don't understand is why nobody is talking about end grain balsa instead. It's so strong and I would bet it's stronger than Nomex, sure it's a bit heavier, but it's commonly available and this is competition is more about being "Industry Strong" than "Aerospace Lite".

If you want to make some of yourself, I can tell you how to make a precision planer, using a std mill.

Re: Is Kevlar Honeycomb allowed?
 

If it costs that much, you had an illegal ramp. $400, legal; $401+, illegal. (for the smallest available COTS quantity)

Re: Is Kevlar Honeycomb allowed?
 

I'll say it one more time. List some companies I can call today and order some of these materials for my team. Give me the name of a prepeg house that will sell my team a small quantity prepeg that meets the cost reqirements and then we can all go forward and use these wonderful materials. Until then I contend that these more exotic materials are not legal for FIRST use. I went thru the Thomas register last year looking for vendors. I found no company that would be legal by First guide lines. The biggest problems were minimum order quantity, Minimum dollar amount per order or they just do not sell to the general public. I could have gotten some material for our ramps last year from a friends company. I did not because I could not account for it By the rules. May be I should just ignore the GP and take the atitude other teams do. It's OK util some body calls them on it.

Re: Is Kevlar Honeycomb allowed?
 

For small amounts I depend on Aircraft Spruce. Our shop is in Corona, CA. and within a couple miles of their wherehouse, but they ship everywhere and have an Eastcoast wherehouse too.

When I have time to wait for products like S-glass, I use Thayercraft ind. I found them on Ebay and prefer dealing with them, instead of local resources.

Products like Kevlar and Carbon Fiber Tow or Cloth, I prefer to wait for on ebay because most of those vendors are selling Carbon products that have expired their shelf life and are no longer suitable for aerospace manufacturing. Once the expiration date has been reached, it's value drops dramatically. I have no idea how this works out in the rules, but composites that have exceeded their shelf-life, are basicly scrap and are sold as such.

Until the middle of 07', many of the composites were in short supply because of Iraq. Before that time Carbon and Kevlar prices were sky-high, If you could find it at all.

Aircraft Spruce
(my guess is most people already know about Aircraft Spruce)

Aircraft Spruce-Ebay outlet

Thayercraft

I'll post more sites after I visit our shop today.

Also there are work arounds for composite materials, like the end grain Balsa and with good assembly techniques and the use of heat (this time of year is a must) and/or perferated plastic sheets between your Peel-ply and Breather Cloth, you can minimize the amount extra weight gains from the epoxy resins and prevent "Bleed-outs" into the Breather-Cloth that sacrifices strength.

Re: Is Kevlar Honeycomb allowed?
 

Here is a list of companies that sell small amounts of prepreg carbon fiber and other interesting composites. They are not my regular vendors, but they are all well established (20+ yrs) and sources for my personal model airplanes.

Model Research Labs

Dave Brown Products

Bussiness with a greater inventory and higher prices (But are still small amount suppiers)

Aerospace Composite Products

CST-The Composites Store, Inc.

(I think CST will be the most helpful for most FIRST teams)

Another valuable source of information is the "National Free Flight Society", They publish a Symposium every year, many of the authors are aerospace engineers and they have published many articles that can be applied to FIRST

I hope this helps out, I'll post more later

Bill

Re: Is Kevlar Honeycomb allowed?
 

I will add that Robotmarketplace also sells small pieces of Carbon Fiber. Their selection ranges from thin sheets, sandwich foam plates, and structural shapes. A fairly impressive selection, though the prices are to be expected... (I have never purchased CF material from them, so I have no comment as to the quality or availability of this material)

Bengineer

Re: Is Kevlar Honeycomb allowed?
 

These are my normal suppliers for Vacuum bag materials, Composites and Resin & Mold making products. They do not sell in small quantities like Aircraft spruce though.

Richmond Aircraft Products

The West coast supplier for Nomex honeycomb and Roahcell high density foams is Technology Marketing, Inc

For resins and rapid prototype mold materials I use PTM&W There are a few new resins on the market (like MGS), but in my tests none of them showed a strength advantage. The PTM&W products were easier for beginners to work with and were generally better in cold working conditions.

PTM&W also sells a wonderful product called RT2C, to make a very strong mold, very fast at room temp. It is a light weight, 2 part epoxy sand like material. We have also used it like somebody would use Nomex or Roahcell, it has excellent
compression capabilities. Here is it's PDF Data sheet

Hope this helps someone