I recently acquired an Escape Velocity 2.6, one of Giant Leap Rocketry's "Ready to Fly" kits.  This kit is a 2.56" speedster that includes everything you need other than a motor and launch pad to build and launch your own high powered rocket.

The kit features Giant Leap's signature phenolic tubing pre-slotted to accept a pre-molded 3-finned fin cannister, a 38mm motor mount, avionics bay, dual deployment and all the hardware and recovery components a rocketeer could ask for in an all-in-one kit.  It looked like the perfect kit for someone wanting to build a rocket that could be used for a certification flight and then flown again and again in a variety of flight configurations.

Photo: giantleaprocketry.com Click to enlarge

The answer was as clear now as it was when I first found the appropriate answer: 'glass it!

I learned years ago that composite reinforcement of a rocket's airframe was the perfect solution to overcoming the normal dents and dings a rocket encounters during repeats assaults of AP time and again.  My first all-composite rocket was a Dynacom Scorpion and the beatings that rocket took — even after free-falling from 14,000 feet the only damage was the dislocation of a fin!  After that, I 'glassed everything!  Straight cardboard, phenolic, it all got a composite skin and the exponential increase in reliability was amazing.

Having 'glassed airframe tubes in the past, I can tell you it doesn't come without its own headaches, but the end result is so worth it that you don't even consider the work on the front end.  But was there a way to reduce these initial considerations?  A quick look around the hobby rocketry composite world revealed a company in Pomona, California named Aerosleeves.

Aerosleeve's "sleeve"

According to their web site, the company provides carbon fiber, carbon/Kevlar hybrid, and fiberglass composite materials to the high power rocketry and aerospace community.  After reviewing the products on their web site, a new twist on an old idea was readily apparent: two of their leading products were "sleeves" rather than sheet cloth — fiberglass and carbon fiber!  Anyone who has ever 'glassed an airframe tube with sheet cloth can tell you about wrapping the cloth on the tube, getting it to stay put and then wrestling with the fraying fibers that always constantly frizz away from the joint.

I quickly contacted Nick Anderson, Aerosleeves' product manager, and told him I was getting ready to begin construction on the Escape Velocity and it looked like their 2.5" fiberglass product would be ideal to add the structural integrity I was seeking.  Nick was very helpful, responding immediately and in less than 4 days, I got a package in the mail.  I was also delighted to find that Nick had provided me with a sample of their carbon fiber product, but that was quickly squirreled away for another project.

The composite material is cylindrically woven "sleeves" of fiberglass cloth, unique in that it doesn't have a seam.  Through scrunching up and stretching out the material, it is able to increase or decrease the overall diameter.  The tradeoff is that scrunching up the material or stretching it out increases or decreases the axial vs. transverse strength by re-orienting the angle that the fibers of the weave have to each other.  The longer it is pulled out, the stronger it is axially.  The more it is scrunched up, the stronger it is transversely.  The ideal axial-to-transverse strength comes when you achieve a 45 degree orientation of the fibers to the centerline of the airframe tube.

Jig holding airframe tube Click to enlarge

After roughing both airframe tubes with 60 grit sandpaper to give the fiberglass resin more bite into the tube, I slipped a short piece of steel conduit through one airframe tube and laid it on the jig.  In each end of the body tube, I wadded up newspaper and packed it into the body tube to position the conduit as centrally as possible inside the tube.  The same thing is possible using motor mount centering rings.  I had already gathered the materials I needed: West System epoxy, paint brushes, mixing cup, and materials to clean up with.

You want to make sure you order more than enough composite sleeve than you need because it is important to not run short on your project.  The Aerosleeves web site makes measuring easy by telling you how much more or less of the product to purchase given the minimum or maximum diameter you are working with.  But it always helps to have more than enough because the ideal layup is where you have extra material that extends off the tube.  This is the only way to get the material to lay flat so that you get a nice square end when you are working on a pre-cut airframe tube.

The Aerosleeves web site has an excellent tutorial online on composite tube layup.  I carefully read this information prior to beginning my project because I wanted to make sure I had all the information I could get about laying up composites using sleeve material.  One of the recommendations their tutorial offered was the use of heat-shrink tape wrapped around the exterior to squeeze excess resin from the cloth matrix.  I didn't have any of this heat-shrink tape, so I would be using conventional methods of composite layup.

My experience with flat cloth was that I ended up brushing the resin on the tube, rolled the cloth onto it and then worked around the circumference of the tube in a perpendicular fashion to the centerline of the tube.  I was about to find out that working with the sleeve material was oriented parallel to the airframe's centerline.  Oh happy days!

I had already played, and pulled and tugged at the fiberglass sleeve, because I like playing with new toys.  This is another reason to order more than you need — all the pulling and tweaking can unravel the ends of the weave after you take the tape off that it was shipped with to keep it from fraying.  You must take this tape off to put it over the tube, just be careful not to unravel the cloth.  I had already cut it to the proper length as well during this playing period, so I was ready to get to work.

Here you can see the lay of the fibers, achieving a 45 degree angle with the airframe centerline. Click to enlarge

I scrunched up my sleeve material for the payload tube and put it over the conduit and airframe, pushing it down to one end.  I mixed up my epoxy, using the West Systems' pumps — one pump of resin and one pump of hardener means no fussing with measuring.  It does the measuring for you.  Don't mix up too much — you don't want the resin "kicking off" on you while you are still trying to get it brushed on.  I brushed one half of the tube and worked the sleeve material down onto that end, and then brushed the other end, re-positioning the sleeve material as I went.

Once I had the sleeve material smoothed out, I mixed some more epoxy and brushed it onto the outside of the sleeve, wetting out the fibers as I went, working the resin into the cloth.  You want to be careful not to float the cloth off the tube, because that only weakens the composite matrix and doesn't produce symmetrical results. 

One of the nice things about the Aerosleeves product is that if you start in the middle and work to the ends, the product stretches out very flat onto the surface.  The more you work it toward the ends, the flatter it gets, making for a very concentric, very strong layup. After I had the fabric thoroughly wetted out, I took a small rectangle of hard card stock and, working from end to end, pulled the excess resin out of the cloth.  This was a breeze!  And in about 1/2 the time it would have taken with flat fiberglass cloth (and about 1/10 of the headaches), I was done!

Here is the finished payload tube. Is it really this easy? Click to enlarge

I am just as pleased as I can be over the relative ease with which you can produce composite airframe layups using the Aerosleeves product.  Nick and Aerosleeves both get high marks for fast service, remarkable products and professional presentation.  If you do any airframe composite reinforcing or tube construction, skips the extra steps and get this stuff!  You will be glad you did.

Aerosleeves, LLC
60 Kellogg Dr Ste 433
Pomona, CA 91768
1-888-804-7295
email: This email address is being protected from spam bots, you need Javascript enabled to view it
website: http://www.aerosleeves.com/
tutorial: http://www.aerosleeves.com/pdf/composite_tube_fabrication.pdf

08-20-2006 11:54 PM  #1
crontab Certified Level Three   Joined: Aug 2006 Posts: 204	Hey, great reading. I just wanted to say thanks for the review. I was considering trying that product myself, as I want to strengthen some kits from the "dents and dings" as well. Hat's off to Aerosleeves. Glad to see good products such as these out there.

08-21-2006 07:37 AM  #2
dixontj93060 Certified Level Two   Joined: Aug 2006 Posts: 39	Second Layer Darrell, Great article. Nice to see some good (great) writing. Curious though... I normally put on a second layer of glass "off angle" as it seems to add significantly more strength. Putting this on while the epoxy is still tacky is pretty easy when you are wrapping with a normal piece of cloth. Obviously it is also better to do it at this time to get a chemical bond between the layers. Yet I have never seen a write up on doing a second layer with the Aerosleeves product. Seems like it would be pretty hard to get a second layer sleeve installed on semi-cured tube... Opinion? -Tim

08-21-2006 01:40 PM  #3
ddmobley Administrator   Joined: Jul 2006 Posts: 2541	Quote: Great article. Nice to see some good (great) writing. Thanks! It's good to be writing again! Quote: Curious though... I normally put on a second layer of glass "off angle" as it seems to add significantly more strength. Putting this on while the epoxy is still tacky is pretty easy when you are wrapping with a normal piece of cloth. Obviously it is also better to do it at this time to get a chemical bond between the layers. Yet I have never seen a write up on doing a second layer with the Aerosleeves product. Seems like it would be pretty hard to get a second layer sleeve installed on semi-cured tube... Opinion? In the past, I have done the same as you. Usually, I was working with 4 to 6oz cloth in the past and a second layer was necessary for additional strength. I have done it both ways: adding the second layer while the first layer was still tacky and adding the second layer after the first one had cured. According to the Aerosleeves tutorial (http://www.aerosleeves.com/Articles.asp?ID=108), section F states: "F. Add additional layers, if desired If you need a stronger tube, add a second or third layer of sleeving now. Once epoxy has been applied to the sleeving, it is impossible to apply another layer. Before applying another layer, carefully tape the radius of the sleeve to one end of the mandrel. Now slowly work sleeving all the way onto the mandrel. The tape will keep the sleeve underneath in place during the application process." The process that the tutorial explains is to put two layers of the sleeve product on the mandrel or tube and then wet both layers at once. This would appear to me to require the use of the heat-shrink tape to remove the excess resin from the composite matrix. You must keep excess resin to a minimum to insure a strong sandwich construction technique, and floating two layers of sleeve material with excess resin would not produce satisfactory results without using some method to extract as much resin as possible. At the very least, it would require additional time to wet out the additional layer of sleeve material. The GOOD news is by working from the center to the ends, there wouldn't be any problem with joints kicking up from the lower layer to disturb your top surface. Now, the fact that the weight of the fiberglass sleeve material I was using was 9.9oz, and compared to the 4 to 6oz cloth I used in the past, one layer of the Aerosleeve product was sufficient to provide the thickness and strength needed for reinforcing an airframe tube. I learned a lot from my father, who was in the yacht building business for 43 years. The importance of a thin, flat as possible sandwich of composite layup was conveyed, even if it meant having to wait and sand between layers before applying the second layer of glass. Excess resin in the layup produces a weaker product. That said, I believe that I could get another layer of the sleeve product on while the previous layer was still tacky. It's not going to move at that point and you just have to make sure you expand it as large as you can and work slowly. I was just pleased I didn't need another layer due to the strength and weight of the single layer.

08-28-2006 01:04 PM  #4
Johnly Certified Level One   Joined: Aug 2006 Posts: 10	Another Aerosleeves convert Nick is a lcoal flier so I had an oppertunity to give the his products a try about two years on an aiframe destined for a M2.0+ flight at BALLS. I glassed the sleeve onto the body tube by cutting the Aerosleeve about 3" long at each end, then closed each end with a zip-tie. I attached one end a ceiling beam by a length of a wire, and the other to a floor weight using a bungie cord. I painted on the epoxy, then used gloved hands in a downward motion to remove the excess epoxy , as well as any bubbles, wrinkles in the Aerosleeve. The tension provided by the bungie keeps the sleeve taught during the curing process. I'll never glass airframe tubing using cloth if Aerosleeve is an option. John in Oregon

09-06-2006 09:13 AM  #5
crontab Certified Level Three   Joined: Aug 2006 Posts: 204	By the way, Nick has some Aerosleeves scraps offered in the auctions here. If you want to try out some of the product or just need some small amounts, this is a good way to get some of their product.

09-10-2006 08:49 PM  #6
LaneKG New Member   Joined: Aug 2006 Posts: 3	I am trying out Aerosleeves on my level three project. I went with one layer of Aerosleeves on the 7.5 inch airframe. I am finding the Superfill, also available from Nick, is a great product. I am not close painting yet. So we will see. Thanks, Greg

09-10-2006 09:44 PM  #7
k3td Earth-bound misfit   Joined: Jul 2006 Posts: 64	Greg, tell us more about your L3 project!

09-10-2006 09:49 PM  #8
k3td Earth-bound misfit   Joined: Jul 2006 Posts: 64	Duh ... I missed the link in your message, Greg. Looks like a neat bird!

09-12-2006 07:48 AM  #9
LaneKG New Member   Joined: Aug 2006 Posts: 3	Thanks Tad! I will give you a heads up when there are updates.

09-17-2006 11:52 AM  #10
Boogeyman Certified Level One   Joined: Aug 2006 Posts: 24	Great product by a real rocket guy and a well done article. B