CLUBS: Andy's wing

bfeist · May 09, 2013, 09:27:42 PM

Hey Andy, how's your wing coming? Did you get the polyurethane sorted out?

Ededge2002 · May 09, 2013, 11:25:39 PM

So both of you are polyurethane ing the wings? Some photos of the result would be cool! Are you covering or painting for the finish? Wonder what the weight difference will be.

bfeist · May 10, 2013, 08:33:09 AM

I'm not painting. Naked Nooner. I have some covering sticker material I'll use for orientation. I'm sure it weighs more than covering, but it was fun to try anyway.

Andy Hoffer · May 10, 2013, 09:22:20 AM

Hi Ben:

I couldn't find the varathane product called "sealer", just clear finish. Is that the same thing?

I'm away till May 19. Talk to you when I get back.

Andy

bfeist · May 10, 2013, 12:07:36 PM

Here's the can and the finished wing.

1/2oz cloth. 4 or 5 coats. Sanded between each coat except the first and 2nd (didn't want to sand the glass). Used masking tape on the edges of the glass so it didn't unravel. Put tape down on the sheet of fiberglass where you want to cut to length and cut along the masking tape.

You have to be careful that the wood doesn't soak up the polyurethane. The first coat before you put any glass on should be super light then let it completely dry. This creates a seal.

Here's a good link with instructions. http://pldaniels.com/flying/balsa/fiberglassing-model-aircraft-with-water-based-polyurethane.html

Ededge2002 · May 10, 2013, 12:43:01 PM

Looks Great Ben!
Did you do the ailerons and tail surfaces too? How will you hinge the surfaces?

its best to have a woodie for a nooner!~

bfeist · May 11, 2013, 10:06:39 AM

Ha! Nice.
I did do the tail as well, but not the elevator. I just had to rebuild the elevator because I made the original too short by accident. I don't think I'll glass it, just varathane it. I'm planning on hinging with the usual CA hinges. I know the ailerons are filled with foam, but Glenn used non-foam-safe CA and he said the hinges worked fine.

Andy Hoffer · June 02, 2013, 12:03:04 PM

Where there are rain and wind, there is hope in the workshop! Ben, I eventually opted for East System epoxy to glass the wings, since I already had it on hand and the urethane was $11/pint. I had forgotten how beautifully laminating epoxy wets out the cloth, and the intermediate speed hardener gives a comfortable 30 minutes of working time. No fumes that I could detect. One coat with a very light sanding. I'll be covering with film so I'm not fussing too much with the finish.

Servo tray for fuse is probably overkill, but I like easy access to my servos to deal with the inevitable stripped gears. It was fun to engineer, build and fit in the tight quarters. AND the extra weight of the rudder servo (I want to try pattern stuff too with my Nooner) and the servo tray will help me secure my 2nd-last place finish while you guys and Glenn duke it out for the top spots.

... And now back to our regularly scheduled program in the basement!

Ededge2002 · June 02, 2013, 12:20:47 PM

I really like your tail servo tray Andy! Well thought out and executed. Four screws is overkill lol. Wing servo trays too! Wow lots of nice little pieces. Any idea of weight gain with the full epoxy on the wing? I used 30 minute epoxy thinned with rubbing alcohol it slows the cure and is very thin. Your going to cover it too?

Andy Hoffer · June 02, 2013, 01:22:15 PM

Three pounds !! (Actually, I didn't measure. But I do have a photo of the excess epoxy left over from squeegeeing during glassing of each of the wing skins (left and right, top and bottom). I started with a 30 mL batch, not knowing what to expect and not wanting any interruptions to mix more if I came up short. Well that quickly led to a 15 mL batch on the next go. Best job was about 9 mL net amount applied of 15 mL mixed, so we're probably looking at an epoxy weight gain of 40 grams, plus about 6 grams for the cloth (180 square inches x 2 sides x 0.75 oz/sq yd) .

I researched fibreglassing, and epoxy in particular, including this informative and well written link. http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/finishing_techniques/apply_fiberglass_finish/index.htm.

I could have run some tests, but the 30 minute working time was fine, and the advice I read (http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/finishing_techniques/apply_fiberglass_finish/02.htm) said not to use alcohol or other thinners. Notwithstanding your demonstrated success with it !

And yes, I am going to cover it too.

bfeist · June 02, 2013, 03:47:50 PM

I'd love to know what your all up weight is before covering. I ordered a 1300Mah battery from hobby king. It should be here by November.

Andy Hoffer · June 02, 2013, 06:39:32 PM

I weigh 158 pounds before covering.

My Nooner, however, should come in at 387 grams + battery, before covering. Candidate batteries are a new HK Rhino 3S 1550 30C at 126 grams, and a 2nd hand HK Zippy 3S 1300 20C at 105 grams, giving AUW of 17.3 oz or 18.1 oz, before covering. This puts me into the heavyweight class! The good news is I won't be affected by the wake turbulence when you guys lap me!!

Andy

Andy Hoffer · July 01, 2013, 11:50:25 PM

Maidened my fully clothed Nooner today in gusty NE winds (20 to 30 kmh) at TEMAC. Two good "getting acquainted" flights, not really pushing it yet. Easy to land. Very responsive. Really wants to climb at higher power settings.

Third flight was an immediate nose dive on launch. I think the interior servo tray mount had somehow separated from the fuse and moved aft, promptly pushing the elevator down on launch. Nice straight lawn dart impact pushed the prop and motor mount straight back into the fuse about one-half inch. Prop blades cut into the front of the fuse about 1 mm deep (no spinner). Repairs completed and looking forward to more practice it with. It's a fun plane.

Andy

Ededge2002 · July 02, 2013, 04:51:06 PM

Trim at speed will be a fair bit of down. I bet you trimmed down and the third launch it dipped just a little on launch.. been there done that. You might notice I now launch mine quite high to prevent this.

Andy Hoffer · July 02, 2013, 08:49:53 PM

I may have done that, but I'm not sure. The issue only happened on the third flight, not the second. But I will certainly be watching for it now !!:) Do you use a switchable program mix for the down trim at speed, or just dial it in "on the fly"?

Thanks for the heads up.

Andy