critterhunter

I'm holding onto your airfoils but a friend came over today with his own wing jigs and helped me cut out a new wing for my scaled up dual boomer. We also changed the horizontal stabilizer. This plane, held together with toothpicks for pictures, has changed it's looks a total of three times thus far. It still needs sanded down a bit. A yardstick was laid across the wing for scale. Here's a few stats:

Controls: Dual Rudder/Elevator

Wing: 6' long. The pictures don't show it well but the wing is 10" wide at the fuse an tapers down to 8" at the tips. It's a USA (SOMETHING) that he brought the jigs over for. The way I understand it it has a bit less lift than a Clark-Y but also has less drag. I'll also being putting dihedral into the wings past the booms.

Plane Length: 4'

Booms: 2' apart

Horizontal Stab: 6x24". It's a Clark-Y airfoil.

Elevator: 3x24"

Verticle Stabs: 11x8"

Fuse: 6" tall x 4" Wide. I made it this thick to safely house a pocket camcorder when it's not carrying my two wireless setups.

Drive System: Single Pusher swinging around a 10 or 11" prop.

I'm planning on a 3 wheel landing gear setup, two wheels towards the end of the booms.

More measurements when I bring in the paper I wrote everything down on.

vtrc

Flew 4 times today, or 4-1/2 times. No more than 30 second flights. But I landed each time after a circuit or two -- usually to avoid an obstacle or bad situation (like wind that came up suddenly). And they were real landings. Brought the plane back to the house intact. a first. Can't wait til tomorrow morning, if it's calm.

critter -- looks nice. 10 inch wing better than 7. Tapering should reduce weight as will some of your other changes like reducing stab size etc. The airfoil was a USA35B, as a guess. Basically this isn't a 2X SO, but a new design. I wonder how the lifting tail will work out

flashsolutions

Lookin good Critterhunter!

I forgot to mention in my build that I put a carbon fiber rod in the wing to give it added strength. This was epoxied in and then covered by the strapping tape called for in the original design.

I also added a strip of 1/8 x 1/4 spruce to form the trailing edge. The wing is now very rigid and can withstand a lot of punishment.

It will be interesting to see what the final weight of your plane will be.

vtrc

Flew 6 more short flights this morning, no crashes. Never got above 30 feet because wind and trim.

This plane needs a calm. 10 oz AUW on the same size wing as the SO, undercambered. Did 3 or 4 circuits of the field in one of the flights. Between treelines. It was easy to recover with this plane, though it did get blown around some.

But was able to put it down gently every time. No damage. Ran out the battery (20F outside this morning). Looking for a calm to trim it out properly.

Really psyched!

critterhunter

Yes, we had this discussion last night when working on the plane. I had/have concerns about the tail wanting to lift. A little would be OK since I prefer my planes a bit nose heavy. The other factor working to my advantage is the motor I'm planning on using should keep this plane at low speed but with tons of torque. The tail wanting to lift should be less at the lower speeds. On the other hand, it's still open to debate and I might just change that before assembling the plane. I wanted to use a flat piece of coruplast for the horizontal stab but he forgot to bring some. Then again, I might just glue two of the Clark-Ys together to create a more neutral stab.

Nice to hear you've been getting some crash-free flights in.

critterhunter

Thanks. Carbon in the wing? A person after my own heart. Carbon tubes (hollow) are stiffer than carbon rods (solid), so I tend to prefer those. It really helps to prevent folding a wing. Anymore I use Gorilla Glue to glue them in. It will save you weight over epoxy and provide a better hold. Just tape over the tube and weight it while the glue foams/dries. The thin trailing edge of the wing: I just clear tape over that and never had an issue, and my trailing edge is VERY thin. I'm hoping this plane will fall somewhere around 2 pounds or less but even at 3 is should fly well. I'll post a ready to fly weight when done.

ken 68

Don't forget to poke some holes in the tape so excess can get out leaving a smooth seam. And coroplast is HEAVY

Ken

critterhunter

Yea, it's heavy, but the wing loading on this beast is probably going to be real low.

Fisher, meant to ask you about that little dual boomer you posted pictures of a page or so back. Is that a new model being sold in the tradition of the aero ace or a homemade job? I like the looks and the single rudder should make it fly pretty well. More info?

vtrc

Don't know, but you might have to give it negative incidence in relation to the wing. Otherwise I think you might be in some danger of stalling the tail before the wing. Tail drop would stall the wing with some question of being able to recover at all.

Double the Clark Y seems okay, but kind of thick (24%). Usually tails are about 10%.

Coroplast seems okay. I've seen it where they cut away a slit in the bottom skin only to make a hinge of the top face.

I bet a flat plate of 3/4" EPS, with a little work to round the front edge, and a little sanding down of the thickness at the rear, would work fine with a tapered elevator of about 1/2" by 3"

Coroplast may be heavy, but you can lighten it like SaucerGuy does with a hole saw and cover with tape. You might be able to cut oblong lightening holes with a hot wire tool, too -- don't know. A foam tail will probably be covered with tape anyway, so the weight difference may not be great for coroplast.

flashsolutions

Oh yes, it was carbon tubes, I really didn't mean carbon rods. The hollow kind like you said. I thought about using dowel rod but since I had some extra carbon tubing laying around, I used it instead.

saucerguy

vt, I'm glad you finally are starting to fly under your own control, it's a good tip given to new pilots to simply practice take off's and landings, it helps get them past the landing worries. Also, when things warm up, you will find it to be much more enjoyable, with personal comfort on the sticks, longer battery life and you'll actually find the plane gets better performance since the thinner, warmer air produces less drag. I'd like to see pics of the completed plane, also, did so 1. come down yet? Also, did you get any of the other gear working and/or incorporated yet?

Critter, you really should try my balsa technique, especially since this is a now a new design, it's much cheaper then carbon fiber and I'm still die hard about using it over it for that reason, it's plenty stiff on it's own, you just gotta plan ahead of time prior to cutting things out to accomodate the slot for it to fit into.

I have two with coroplast tail feathers, even though it's heavier then foam, it aids structure wise significantly, So. 2 even has the entire forward section of the fuse covered in it, it was necessary to get the COG correct and I figured rather then adding just dead weight might as well make it a tank. The other one, it's design changed so much, I never regretted using it as well. If you are cutting holes in it, you still need to put those in before you cut the wing as well or it will be very difficult to incorporate.

I opted to re-gear so 1 with the old brushed gear today, it took a whole 15-20 minutes and it's now ready to take to the air again, this time marathon style since that power system utalizes the stockpile of nimh's I have and I figured it's Easter and my graphics on it are Christian crosses, so did it for the holiday equally. Happy Easter everybody !

vtrc

Hey Saucer,
Yup the 180 and 6 cell Nimh pack is in the plane along with the 10 amp Green Models ESC.

I'm using an older 8 channel receiver in this -- kinda bulky and heavy, but the price was right! I have two different servos -- one of the $3.95 Hextronix (thanks Ken for that tip) the other the GWS Park I had removed from Popeye to lighten it with hextronixs.

AUW was 10 ounces, even though I had some bulky items. That esc is nice and small though -- my old brushless one in Popeye was pretty heavy.

The plane flies well I think as I zero in on trimming it -- I really need a flat calm to get it right -- or fly any amount of time. Wind is blowing tonight, and did all day since this morning.

Popeye is still up a tree. I did get a slingshot, and some chocolate easter eggs at wally world and tried to bring it down by breaking it up. Figured the easter eggs were less likely to kill the receiver in a direct hit than something harder.

These were Reeses filled hollow points. I prefer them for a quick knockdown. I find they tumble in flight for greater impact. Unfortunately the tumble takes the form of a corkscrew more often than not. I saw quite a few shots do a barrel roll right around the plane. That plus branch deflections, premature peanutbutter flak dispersals, and just plain poor aim meant that I scored only two hits out of 40 rounds.

The first punched a 3 inch hole in the loose wing (attached to fuselage). Satisfying, but no effect. The other hit the pinned wing and the whole plane jumped further out from the tree. But it was still hung up.

The ground was littered with spent easter egg wrappers. They peel off in the first few feet of trajectory. The air was filled with the smell of chocolate. Remembering I was in bear country, it occured to me that I had just chummed the area. The get a little bold after hibernation, on an empty belly, and the woods started to look a little too empty. I wasn't sure how much a deterrent I had with the slingshot and one last round of Reeses chocolate covered easter eggs. Would that turn a bear? My mind shifted to the Darwin Awards, and I suddenly felt like I could end up a winner.

Popeye is still treed.

saucerguy

I'm glad you got that gear to work for you, being airborn is much better then just talking about it.

Bears, really makes me think, now if you can sling some bait onto a close by branch, the bears or vultures would tear it off thus bringing the plane down if you tie it in really well through the slack, hehe.

Fisher

vtrc,

Congratulations on getting airborne. Sure makes you feel a whole lot better, like Saucerguy said, to be flying and not rebuilding after every attempt. Well done.

Critter,

That little yellow twin boom Bi-plane is a Silverlit PalmZ that should hit the European marked soon. It will take 6 months or more probably before it gets to the US. Looks great and has a working rudder. I can't wait to get my hands on one.

Your revised upscale build looks very nice with the current proportions. I relaxed a bit when I saw the recent photos. Funny how simple esthetics can have a physical impact on you.

vtrc

There's just got to be a way.

Perhaps a small rescue helicopter......

vtrc

Sorry about the toy reference earlier, Fisher.

Like Popeye was really an adult plane....

They're all toys when you think about it. The idea is to have fun.

saucerguy

VT, you'll eventually figure out, I'm not the type to just walk away, it takes some serious insane obstical to get in my path to wash my hands of it.

Your plane would be down by now, long ago if it was mine, just trying to prod you to take some action since it's still frozen and not shorting out until the thaw... Not trying to be pushy, it's just my nature to never give up.

The foam it's made of is packing material, the gear is not, so if you gotta destroy the plane to get the rest down, do it, otherwise you lose alot more then the original bird.

critterhunter

Here's an update on my huge dual boomer. I've figured out a way to secure the two-piece wing to the fuse and booms. In the picture it's already held to the fuse using basswood glued to the top of the fuse and some ply sitting on top of the wing. I threaded the basswood for four nylon bolts. The two booms will be secured in a similar manner with two bolts per boom. Right now the booms are resting on the ground so they are lower than they will be. I'm planning to use two carbon tubes (one in each wing) that will slide into a sleeve in the other wing for strength. The tubes will reach out past the booms to prevent the wing folding. The tappered 6' wing (10" at fuse, 8" at tips) is positioned so the leading edge is straight and they tapper is in the back. I decided on coruplast for the horizontal stabilizer. I'm probably going to install a flat piece of carbon across the leading edge of the coruplast to prevent flexing and reduce prop wash vibrations (it's going to be a pusher). The 3" wide balsa elevator isn't in the picture yet, but that should help stiffen the trailing edge of the coruplast. Of course the fins/rudders are also absent in the picture. I may also install carbon tubes in the booms and connect those to the flat carbon across the horizontal stabilizer to prevent them from bending. Sorry about the dark photos (bad lighting). She's all sanded down and ready for more assembly.

vtrc

critter,

67 ozs AUW will give you the same wing loading as your smaller SO.

If you come in under that, she'll feel lighter than the smaller plane.

For performance similar to the standard Foamflyer SO of 16 to 20 ozs you'll need to come in at between 40 and 52 oz.

vtrc

Saucer,

Oh, not giving up. I go there every day. Shot rocks at it with slingshot yesterday. I got no problem with breaking it up if I could hit it. Just a lot of branches in the way and a long way up. If it was 10 feet lower, it would be a lot easier.

The easter eggs worked better than the rocks. The rocks were really all over the place. Not too easy to find them at this time of year, either!

Acorns would be ideal, but, none around. You want something round, big enough to break the foam, but not too heavy for the slingshot. Regular ball bearings would just pass through the foam without shifting the plane. The biggest problem is the fiberglas strapping tape holding the plane together. If I could break that it would come apart.

I did get binoculars on it yesterday. The left wing is in a fork, with the inboard part over the main branch. The right wing and fuselage have broken the left wing at the joint and are loose, but all that tape is holding it together.

ken 68

Do me a favor and shoot a big nut with some of that construction twine tied to it. Have a string that will reach up and back down. It might take several shots to get it just rite. But with the long string you have all the shots you need. Thats how a southern country boy would do it. My wrist rocket & string goes flying with me and I don't need it.

MURPHY'S LAW

Ken

critterhunter

Did you do the math with this tappered wing's dimensions (10" at fuse, 8" at tips)? I also think airfoil is called a USA27. Thanks for doing the finger counting for me. It sounds like I should easily keep the wing loading very low to moderate because I'm guessing it's going to weight somewhere between 2 to 3 pounds or so. I'll post a bare fuse weight when done with that.

critterhunter

Some more work and info on the build...

The digital pocket camcorder is going to go into a chamber under the belly right at COG and be held via velcro straps and some soft foam. I'm going to make the chamber so the camera can be held for a side vide (through a hole in the fuse) or a straight down view. The 2000mw 2.4ghz CCD setup will also go in the same chamber when I'm not using the pocket camcorder. My third 800mw CMOS unit is so light I'll just slap it on anywhere that strikes my fancy when using that.

Reason for the 4" thick fuse (6" tall) was to provide a large and safe enough chamber for the pocket camcorder. I don't care if the larger fuse costs me some drag, I just want to make sure the camera is probably going to remain safe even in a bad landing or worse.

Played hookey from work today because I have to do my taxes, which I still haven't got to yet. So, did a little more work to the plane.

Right now the rods are drying in the wings with gorilla glue. I ended up opting for fiberglass rods rather than carbon tubes since I've got so many of those things sitting around from the garbage picked patio umbrella. A bit heavier than carbon and a little more flexible but they'll work fine regardless. I mounted them in channels about 2" from the leading edge of the wing and their extra weight should help me with getting COG right. They run the entire length of a wing and then sleeve into aluminum tubes (from an arrow) in the other wing under the ply/basswood area. When the ply is torqued down onto the wing via the four nylon bolts threaded into the basswood it should provide a pretty strong wing structure. Will post some pictures later.

I've also got a piece of flat carbon drying to the leading edge of the coruplast right now. Later today I'm going to groove the top of the booms for their carbon tubes for strength there. It'll be glued from under the basswood on the booms and run to the tail. Decided to use carbon back there to keep the tail as light as possible. After that I hope to drill and tap the boom bolts and then install the verticle fins/rudders. Should be able to complete the body today to where it's ready for electronics.

vtrc

Critter,

USA27 has a little hoogie of undercamber on it at about 4" in from the leading edge (on a 10" wing)-- is that what you have?

Cool! My Heath Parasol UL has a similar foil.

Yup, I did take the taper into account -- 648 sq in.


Ken,

okay, okay, I will. I'm a half southern boy. I eat grits with my eggs, and CDM coffee.

But I know what's going to happen. I'm going to have a plane AND a ball of string in that tree.

If I get the plane down that way, I'll send you the popeye insignia.

critterhunter

Well, you've got me since my friend brought over an asortment of wing jigs, took one look at the plane, and said..."Let's try these." He then realized one of the jigs wasn't what he wanted to use but said "This is a USA27. It'll work great." I'll provide more details when I have another talk with him. I kind'a don't like having a strange airfoil that I don't have a wing jig on hand to cut new wings out with should need be.

More progress:

The fiberglass rods and aluminum sleeves in the wings worked out well. Secured the wing to the fuse to check flex. Bad news is the wing will bend pretty far due to the fiberglass but the good news is there was no problems with the foam. Reminds me of a fiberglass sail plane's wing that flexes in flight. It will stiffen up a good bit more when I put Extreme strapping tape over the tubes and on the top for dihedral.

Got the rudders cut out of the fins and hinged with heavy duty dubros. Did the same with the balsa elevator joined to the coruplast horizontal stabilizer. Booms are drilled for the nylon bolts. Next will be installing the carbon tubes in the booms, glue the fins/rudders on, and she'll be just about ready for electronics.