Home made "Glider Box"

[BryanB]

Since I haven't acquired an enclosed trailer yet I thought a "Glider Box" that I can put in the back of my truck with the tailgate down would be expeditious and cheaper for now.
Looking at what's available that is already made reveals the "Cobra trailer". Very nice but but a lot of money just for a box.
I thought, that looks simple enough and I've never made a foam and fiberglass project that size and I bet I can make one cheaper. It's more expensive then I thought it would be to make one with foam and fiberglass but it is light weight!

I started this a couple months ago but I'm almost finished with it but as for cheaper, not as inexpensive as I had thought and definitely not for the amount of labor and time. The foam was the cheapest part at less than $40 for three sheets of the 1/2" insulation type foam sheets. But enough glass (cheapest 6oz I could find) and resin (West systems) for three layers inside and out boosts the expense greatly. The box is 8ft long, 20" wide and 17" tall. So far I have about $220 in just glass and a little over a gallon of West Systems (Not too bad from Amazon) resin/catalyst into it and need a couple more layers on the inside of the bottom half. You could definitely use a cheaper resin but I've always had good luck with West System.

It's been a fun project and I'll post more pictures when it's done but if you really need a "box" for your sailplane it isn't a bad deal compared to one of those "Cobra" boxes, if it'll even fit your model. Honestly though spending the money on an enclosed trailer is the end game but this box, after I add wheels, will make it easy to safely drag the model to a cliff or other remote location not easily accessible.

[gunny11]

Cool, will be watching with interest .

[roo hawkins]

cool . I built a roof there is a thead on scalesoaring uk https://scalesoaring.co.uk/phpBB3/vi...hp?f=12&t=1340

[BryanB]

Great job! I thought about wood but was concerned about the weight. Would have definitely been cheaper.

[roo hawkins]

Thanks . It only cost £40 uk pounds . And is 3 meters long weight is 4 kg less than a 2.2 meter Thule box

[BryanB]

It warmed up a little and with the addition of my new heat lamp bar setup I was able to get a little bit done today. Mainly just added the rudder box.

[ARUP]

That looks pretty sturdy! I built a BIG blue foam box for my Charlotte. Since the crash it would be a nice coffin for it if I decide to bury it!

[BryanB]

Yes, I am way over building and thinking this thing. I have to keep telling myself it's just a box and doesn't have to fly, pass the judges inspection or survive a hurricane but like most of us we tend to be bit meticulous about the stuff we build. Temps here have been too cool for some finishing glassing but getting close. It's a good learning experience for a first attempt at this sort or project.

Working and sanding large fiberglass projects is a nasty business. Think I'll make the next one out of wood with maybe a single layer of glass for weather proofing.

[BryanB]

Forgot to post photos of my finished box before HH Aerotow. For those that didn't see it here's the finished product. It weighs more than I thought it would at around 20lbs empty. Mainly because I got carried away and put too many layers of glass. This also boosted the cost way more than I thought it would but having started the project I decided to finish it regardless.

I didn't use any sort of struts to keep it open. I used marine take apart motor box hinges so when it's fully open you can slide the top and bottom apart if you want. I used a cheap bath hand hold for the handle from Lowes. Used rattle cans to just paint it to minimize additional cost of colored resin but it still took 10 cans.

So, it took about three months of on and off working, lots of sanding and itchy from the fiberglass and a little over $500! We all learn from our experiences! Resin and glass where by far the most expensive elements. Should have just used a cheap resin instead of my West Systems. Next box will probably be light ply or just Luan and see how that works out if I need to build another one. This foam and fiberglass job is pretty sturdy though. You can sit on it and would travel in the back of a truck or maybe even strapped onto a luggage carrier in the weather.

[ARUP]

Bryan- thanks for letting me see your nice sailplane box at the Horizon Hobby Aerotow. It is pretty nice. Ten rattle cans... whew! You probably still have snake nightmares! Ssss....sss...sss...ssssssssss... sss...sss... ssssssss.

[BryanB]

Yes MK, was surprising the square footage of the box. I completely underestimated the material costs.

[edfmaniac]

Nice box!

I'm finishing up the ASW22 container. Just need to figure out how to make the end cap to cover the extra 2ft of wing hanging out of my 8ft box. LOL And build a rudder box. I guess it wouldn't hurt to seal it in the event I get caught in weather. More hardware and wheels to come as well.

[BryanB]

Looking good!

[ARUP]

A box is being built for my ASG29 currently. Here is the box made for the Balestruccio. The box is made from 3/16" ply with quarter round in the corners. It was then stained and varnished. Blue foam inserts support the model. I added the felt design inside the lid in case it ever gets put on display. The boxes are nice in that if the sailplane gets crashed they double as a coffin! The camera made the colors look odd. They are green, white and red like the Italian Tricolor. It looks like the Irish Tricolor in the pic!

[edfmaniac]

Just the final hardware to go, and a rudder box later if I think the extra safety is needed. But's it's pretty darn secure as is. I have a control surface lock for the rudder now too so it physically can't be moved beyond a couple of degrees either way.

[ARUP]

That's pretty nice but wait a minute... you sure it isn't one of those 'Saw the Lady in Half' boxes? lol

[edfmaniac]

Let's hope no one tries.

[BryanB]

In my second attempt at fabricating a glider box using less expensive materials I went with the same pink (XPS) foam board but used construction adhesive for foam paneling to attach a really cheap 1/8" luan type of panel on the outside of the side pieces and on both sides of the bottom piece. I haven't made a top for it yet. It's already heavier than the foam/fiberglass box I previously made but without using yards of 6oz. glass cloth and resin its way cheaper.

Here's the box so far that I'm working on for my H9 ASH31.



I wasn't originally going to put sides on it so down the center longitudinally I glassed two parallel 2" "spars" of 1/8" ply to aid in stiffness. Even with the 1/8" ply attached to both sides of the bottom piece it was still pretty flexible. The "spars" probably aren't necessary with sides attached.



The construction adhesive for foam paneling is pretty thick (Tube cartridge in chaulk gun) but I didn't want to use expensive epoxy at the time to attach the ply to the foam. Even though it works I should have used a toothed grout trowel so it wasn't so thick. It left a fair gap and ended up not being the cheapest option.



I ended up using 4" glass tape to reinforce and protect the outside corners and edges.



I did some research on alternate methods of protecting a surface with some sort of "glassing" process and found that for many years folks have been using canvas and Titebond glue for boats and homemade travel trailers. They call it "Poor mans fiberglassing". You can Google it. I also thought about using a polyurethane with some sort of fabric. Without having to use expensive glass I haven't determined if these other resins,glues or finish products would have the desired stiffness. It certainly would provide water and dent protection and sounds like it may be a bit heavy. I need to experiment if a polyurethane/polycrylic coating over pink foam will protect it from less expensive polyester resin. Or, if polyester resin will adhere to a polyurethane or polycrylic material.

[BryanB]

Did a little more research on foams and found out polyurethane foam is compatible with polyester resin. I thought great, do they make 1/2" sheets of polyurethane foam! Yes they do! For $300 a sheet!

Some other things I came across for possible glass cloth alternatives from the surfboard guys are Bamboo and Basalt cloth.

[BryanB]

Something I discovered after using my original all foam and fiberglass glider box was having the wheels just mounted to the outside edges became a liability when maneuvering it in and out of places as the wheels would catch on things. On my latest Foam/Luan box for my H9 ASH31 I decided to inset the wheels so that even the axle bolt head is less than flush with the sides and it's proven to be worth the extra time and effort as the box now maneuvers more easily in and out of tight places. Just something to consider for those contemplating building their own box.





I found 1/2" industrial felt (F26 grade) that can be purchased in small quantities on Amazon for the wing cradles.



Everything fits nicely into the box.


It looks like a coffin but I wasn't going for looks. Just a nice storage/transport system to protect the model. Also wanted a mostly flat top so I could stack things on top.