Skyray 35 Wings

Hi Rusty,

You mistake my motivation. Breaking models is something I do on a regular basis. Particularly getting over ambitious close to the ground.

Why? Because I like to see the model close up as it flies by. Most of the damage I do is light and quickly repairable - the majority of the planes (RC) that I regularly fly are foamies and very tough. Also because they are quick to build and easy to repair - I often throw caution to the wind and have little discipline by making snap decisions. ( I snapped a wing recently doing a barrel roll close to the ground and too fast - However, this was a 15 minute repair and the "battle scarred parkflyer was back in the air again)

You are quite correct to point out the effect that a balsa bashing build has. I am exceeding cautious with my balsa builds and always maintain a safe height and any damage has been a result of a wobbly landing (easy repair but time consuming)

I have only smashed one of these and this was through experimenting with AS3X stabilisation. Took it out on a windy day to test it - lost control immediately after launch - treed it - the resulting plummet from the tree totaled it. Post mortem established that I had set it up in reverse. So it didn't fight the wind, it rolled even further with it. This one had been repaired a few times due to my experimentation and carelessness (checking CG after a battery upgrade!)

However, I digress.

What I haven't made clear is that the pictures are screen snapshots from one of my CAD/CAM systems. It took one hour to prepare the first set per the original Skyray design and 5 minutes to clone this and modify it for the sheeting.

The pictures of the ribs can be printed and used as templates for cutting and following the procedure you adopted for sandwich sanding.

The material thickness can be altered in seconds and the ribs individualised.

When I have finalized everything - it takes about 20 seconds to produced the G code for my machine and around 3 minutes per rib to cut. 20 ribs in an hour while I drink coffee and smoke cigarettes!

What I am really after is - if you had the opportunity - with no time restriction - to build a wing for the Skyray with the same profile - what would you change to make it lighter, stronger and more flexible?

Replace the wing with a foam core and make it a plug in. Use 1/64th play as a saddle around the cutout in the fuse. The saddle being a 1 1/4" wide and core out holes in the foam. Cover with laminating film or equivalent. Foam wings are far stronger in terms of flex and ground pounding. They also can be repaired easier. Certain profiles actually fly better with a little weight behind them. They have a lot of side area and can be bounced in the wind pretty hard. Think of it as a tractor trailer going down the highway with a side wind. While you don't want the plane to be a brick, you won't be penalized too badly if the plane misses the kit's target weight by an ounce or two. While the framed wing may be lighter than a foam wing, it depends on the foam used and the construction and covering used on the foam. In terms of strength, I've driven planes straight in from over the top of the circle full bore and flew the foamy 5 min later with a bit of clear packing tape or epoxy. Your not doing that with a built up woody.

My profiles with foam wings have electrical tape holding the wing to the fuse or just a few dots of Gorilla glue. This allows the wing to cleanly break away from the fuse. The plane would also have external bellcrank with the platform doweled and pinned to the fuse. The techniques I described are similar to the Ukey .35 which was a terrific success some years ago. A simple design with about 500 squares for a .35. It could take punishment like no other model available and flew extremely well.

One major problem with control line models is the difficulty accessing the bellcrank without major surgery. Years back most would think that more elevator in terms of size and fast moving controls were the key to success. Look at a Flite Streak for instance. The Skyray .35 is essentially the same squares as a Streak and has very similar characteristics. A very small elevator and slow controls are the key to success. Having the ability to change your bellcrank settings on external controls is really a nice feature. Ken

The Ukey 35

After looking at Ken's post re foam core wings - I had a scout around and found this
 
http://winshiprc.tripod.com/building_techniques.htm
 
A combination of the best of both worlds.
 
I also find the concept of an accessible bell crank appealing. I have just got myself into a right mess buidling the Frog Aerobat. That will be the subject of another post when I have resolved the issue(s).
 
Now that I have "mastered" the software - I am well on the way to finishing my "wing rib cutter" (amongst other things). I am now fine tuning the axes for accuracy.
 

Poor curtains! cutting wood will make a mess!

Phil

pkrankow wrote:Poor curtains!  cutting wood will make a mess!

Phil

Wood vacuums off - the cutting fluids and metal swarf from the milling machines either side doesn't!

I forgot to mention.

Curtains make very good towel substitutes.

I have been playing close attention to Rusty's build and this weekend I finally stoked up my CNC router. Not a patch on the one Roddie uses to create his little masterpieces but a handy size for DIY use.

I put down a couple of strips of double sided tape.



Apply some wood



Fire up the machine



and



It didn't take long to do these





This is part of the structure for half of the wing (still subject to modification)



I keep trying to resist taking it too far!