VoughtF4U
Posts: 377
Score: 100
Joined: 1/4/2002
Last Login: 4/6/2013
From: Gray, TN, USA
Status: offline
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First, let me apologize this is so long...
After reading up on this thread about the pizza boxes I decided Friday night I had to make one for our club Fun Fly on Saturday. With 8 hours to go, I cut a 24" by 24" piece of 4mm coroplast sign board. I made the control surfaces 3 inches. I set my CG at about 20% (between 4.5" and 4.8") I glued a Lowe's cheapie yard stick down the center on the top all the way from the leading edge to the control surfaces. I glued the remainder of the yard stick about centered on the bottom.
The O.S. .46 LA (smallest I had) engine mount was 1/8 inch light ply cut to fit the engine and it glued on to the wing. It was long enough so that about 5 inches were glued to the wing. It was notched to slip around the yard stick. I made an identical piece and glued it to the bottom so that they sandwhiched the wing and the engine. I also added some small 1/4" hardwood doubling sticks to add a bit of strength to the mount.
With 7 hours and 45 minutes to go, Servos were mounted on the cg (anyone else have problem figuring out those damn nylon zip ties... Seems like every time I put the stupid strap in the wrong side of the locking mechanism) and the batttery and rx were velcroed to the yardstick. The velcro allowed the battery to be shifted forward and backward to adjust CG. I also added a fin and rudder made from 4mm coroplast. Used coroplast piece bent at 90 degrees to glue from the wing to the rudder to add strength. With about 7 hours to go, I am wondering what I forgot since I haven't been able to use my sand paper, filler or covering iron yet.
Saturday, prior to the first flight: One of our experienced club member took one look and told me that if I clipped off the front corners it would probably fly better. I was thinking "it is a piece of sign board, how good could it fly in the first place. Besides the sign boards I see blowing around peoples yards in a storm dont seem to have problems flying, and they don't even have servos or an engine".
First flight: Launch was great, straight and level and very stable. Hard to fly because i was laughing so hard. Engine died at about 50 feet up and 200 feet out, maybe 10 seconds of flying. As soon as the engine died it rolled inverted and piled straight in. Hmmm, note to self, deadstick glide ability not the best but better than last coroplast contraption. No damage but a cracked motor mount (darn light ply, wonder why it broke?). Not many people were there yet since it was the first flight of the day and the fun fly hadn't officially started, but I still heard several people laughing. I missed the award certificate for first crash of the day because I hadn't signed the registration form yet.
Second flight: A little CA glue later (mostly on my fingers, got a little bit on the motor mount) and a quick tune of the engine I was off and running. Launch was again flawless and it flew straight and level and very stable. It was a little touchy on the controls and a bit fast, but then I remembered I had a left stick that controls the go juice to the engine. Rolls were fun, loops were nice, low fly bys were a hoot. Once again, very hard to fly becasue i was laughing so hard and had a bunch of people standing around laughing too. Then I hear from the back of the crowd "Hows the knife edge". Rmemeber that the side area of the fuselage is a whopping 4mm by 24 inches, plus a little rudder. So I rolled it 90 degrees and fed in full rudder. Needless to say full rudder was a bit much since it confused the airplane so much it went round and round really fast in a spin. It kept spinning no matter what I tried on the control. Down she went with the only change in the spin from the control inputs I was giving being the speed of the rotation. People were once again laughing at my plight and inevitable impact with the ground. So much for knife edge passes. Any way, about the time I give up it stops spinning and I barely make a pull out at about 10 feet and people are cheering and clapping like I did it on purpose or something, oh yeah, I meant to do that. Landing was another dead stick, roll inverted and hit the ground, at least it doesn't float down the runway forever like some of my other models, I hate walking way down there to get them.
Thrid flight was the limbo competition. I did okay on the first pass but clipped the ribbon on the second. It is a decent limbo plane if you remeber to pull back the go juice lever on the left. Oh, and then my wife showed up and everyone wanted me to show her the knife edge pass thing. So up high I go, roll it on its side and full rudder. Hmmm, started spinning again and this time I made the pull out a little low. First time it pulled out it was heading down the hill across the field. This time it pulled out straight into the hill. More laughter...
Fourth flight was the radar speed gun passes, fastest flight wins the award. This is what seperates the men from the boys in the club, oh wait we are all boys at heart. Anyway, so up I go with the other flat and fast planes like a diamond dust and a rapier with their tuned pipes and racing motors screaming at 30,000 rpms, I tell you, my O.S. LA was doing her best to sound intimidating at her 10,000 rpms (hey, at least we made it into the 5 digits). Once again the laughter starts (did I have a kick me sign on my back or what, every one started laughing every time I flew this thing). While someone else was making their pass I tried a climb and dive for speed practice run. Luckily only a few were looking while it dove to its doom.
Needless to say a lowe's cheapie yardstick isn't much support for coroplast, next time I'll try the ones from Home Depot. In the beginning of the dive that LA really wound up, she must have unloaded to at least 10,500 rpms. Then you could start to see the coroplast flexing and waving. Looked like a magic carpet ride with no one at the controls. Then the waving got worse and about this time it is time to start the pull to straight and level. About this time I see the front 4 inches of coroplast fold under and it does its best ground hog imitation, she impacted and buried all but the last inch of muffler. Coroplast sheeting flew another ten feet, gas tank made it another 20 and the battery made it an amazing 30 feet. Never did get the radar reading... I guess this all wouldn't have happened if I clipped the front corners like I was told in the morning.
Then to add insult to injury, or maybe it was justification, those that laughed at me gave me outstanding pilot award... Evidently it takes a really good pilot to bury an engine so deep!
These things are a blast... Go out and build yours today! Once again sorry this is so long!
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"Mix ignorance with arrogance at low altitude and the results are almost guaranteed to be spectacular"
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All Forums >> RC Airplanes >> Profile and Fun Flying Planes >> Pizza box flying 
Pizza box flying - 
)but i cant decide which one.... 
Coroplast pizza box and high speed flight don't mix - 
but dont expect the elevons to move at high speeds lol. we use any old doggy standard servo. mine flys slow enough
Well that is another story) It did not want to roll fast. 
) 
