ktaylor

hello to anyone who reads this. I recently bought a kit for a remote control plane that is a replica of a plane called the BD-5. I got it on ebay for 99 cent and 19.99 in shipping. I had no clue what I was buying, all i had to go on was the photo and the seller only answering half a question about the size. here's the specs.

wingspan, 32 inches
chord 6 inches w/out aileron
ailerons are full length 3/4" wide balsa
fuselage length, 21 inches,
recommended motor, speed 280

I'll include some pics of what I got and what the pic looks like on ebay at the end of this. It appears to be hot-wire cut from blue insulation foam. There really isn't much to the instuctions, and the kit is far from being ready to fly or almost ready to fly. Comes with no electronics ( fine by me, i prefer my own) or covering for the foam. The instructions recommend using monocoat for a covering, i'm going to sqeege some epxy over it to give it a little added strength & rigidity. The wing is two peice with no dihedral. I'm going to join the two halves with a fiberglass rod & a dowel rod. Will have to either melt a trough for the rods with a soldering iron, or carefully carve one out with a razorblade. AM also thinking of adding a very small amount of dihedral to it. The tail surfaces, you get a template & a sheet of color plast to cut them out of. Colorplast, for those who don't already know, ( i know now,, hee hee) is plastic cardboard.
The fuselage is made out of two inch think blue foam, just the profile of the fuselage. So, i also have to carve the fuselage to the shape. 50 grit sandpaper makes a great rasp for this. I'm going to make a few curve templates to lay over the fuselage to get an even round curve to it & see if there are high & low spots. From what the instructions say at the very end " you are finished! It's recommended giving it a test throw in an open area so you can get used to the planes speed." I'm really hoping that means this plane will be fast. It has a very low profile airfoil, almost symetrical, so it should have low drag coeffecient from that, and only 192 sq inches of wing area. But as it sits I think the plane is maybe a 4 or 5 ounces at most. Should be an interesting build.

Oh, and for those who are interested, here is a link to the seller where I got this plane from.
http://stores.ebay.com/UltimateTShir...Q3amesstQQtZkm

I'm also going to be using a bp-21 brushless motor that you can get from Balsaproducts.com with a 8x6 prop, or possibly a 7x5 folding prop with the blades turned around for a pusher.

ok off to start building......

ktaylor

ok, back again,, three hours into this so far

I'm gonna have to try and get this straight on how i managed to achieve a decent looking fuselage. OK, first, I used a straightedge to draw a line from the point of the nose to the leading edge of the horisontal tail slot, then drew a perpendicular line starting at the leading edge of the wing,, on both sides of the plane. From there i used this lead/rubber flexible ruler that i have ( you can find them at Staples for around $5) to draw a line down the middle of the fuselage nose to tail, across the roof and the belly. then from there starting at the nose point on the roof & belly, using my flex ruler to make a nice curve that starts at the tip of the nose & meets my wing leading edge line.

From there I used one of those utility knives that you can snap off a section of the blade for a new point, to slice through the fuselage, top to bottom following my curve i made on the roof and belly. I rapidly learned that you want very little forward pressure on the blade & lots of stroke. just let the blade slice through the material& gently work it's way forward, otherwise the foam will ball up on you & leave pock holes. So, from there I started slicing off paper thing layers of foam to gradually make a rouch curve from top to side, using my template ( made from pop can box), here & there to see how close i was getting.

For the tail end, i made a mark on the back of where my motor will mount & worked from there, a center line, tangent lines, etc. Oh, I forgot about the feather sanding. I call it feather sanding, cause that's all the more pressure you want to put on the foam. I was using 150 grit sand paper, to do it agian, i'd use 180, or 200+, really fine stuff, but 150 was as fine as i have for now.

SO basically, tonight I have made a huge mess on the floor, have a sore shoulder, stiff neck, and stiff wrist. But the results are nice.

Loubud

Way to go Kate. Looks sorta good.

ktaylor

lou,
I'd stick my tounge out at ya & make a raspberry, but i don't know how to spell that sound. Liz has to work tonight, so after I get Gabby into bed I'm hoping that I'll get farther on it tonight. If it flies well when I get it done, order one for yourself & ship it to me, I'll build it for ya, cause I know that feeble old mind & hands of yours aren't up to this kind of project. OK, so maybe it's just the meds you're on that give ya the feebleness,, man, it's no fun makin fun of ya when I remember the meds.... Thanks though Lou.

Glacier Girl

My Feedback: (4)

Man, you are going to be a whittling fool.
Just a tip, intead of melting a ditch for the rods, use a Dremel with a router bit. Cuts nice smooth cuts, and is easy to keep the depth correct.

Loubud

Hey, come on Kate. You can pick on me any ole time. Chicken.

ktaylor

GG,
Thanks for the tip, come to think about it, i have the router attachment for my dremel, and I also have a small hand held router that could work, I think the dremel will work better though, hafta see if i can remember where the attachments are for it. I'm really curious to see how fast this little thing is gonna be. It says speed 280for a motor, the bp-21 should be a vast improvemnt over that, plus with the pusher configuration the lower wieght of the bp-21 should make it a little easier to get the correct c.g. Which the instructions suprisingly says where it is located, hey that's a step above the badius instructions. "2.25 inches back from leading edge of the wing" Cool. Hmm, that seems a little far back to me though, that would be around 37.5 percent chord. hmm, hafta do some test throws without any electronics in it, just as a straight glider balanced out at that point, see what happens.

ktaylor

ok, didn't do much tonight on the plane. A little extra sanding & put the wing together. I couldn't find my dremel tool, found the router attachment for it though. Got to thinking I loaned it to a guy from work about 8 or 9 months ago,, gunna hafta bug him about it tomorrow. Thanks GG, otherwise I would've fogotten about it. So, i ended up using a straight edge and a utility knife. I used 1/8" fiberglass rod that was from another plane I have, ( trashed badius wings) , one was around 12 inches long, and the other was 18 inches. I put the longer one in front. I placed one 2 inches forward of the trailing edge & the other 2 inches back of the leading edge. Cut the grooves, ( when cutting this stuff, you gotta use a very shallow blade angle and pressure on the straight edge to keep the foam from balling up on you), then flipped the wing over & used fiber tape on the top seam, then a small 2 inch square peice of fiberglass epoxing the two pieces together. Oh, also a small amount of epoxy between the two halves. Then after curing, i flipped the wing over & found out that the little piece of foam that were beneath the wing left small indents in the surface. Lesson learned, always make sure the work area is clean. Gunna hafta fill them in, probably with a little extra epoxy & foam dust mixture. Epoxied the glass rods in place, & smeared any extra across the surrounding surface since I'm going to give the foam a skim coat of epoxy anyhow. Almost thinking of polyurethane, see how that does on a scrap piece of foam. Here's the pics. Hopefully I'll get to work on it tomorrow night, although Liz doesn't hafta work, those nights are hard for me to get some plane time in. Maybe she'll be nice to me. If not, then hafta wait till friday night.

ktaylor

ok, made some progress tonight,

Finished skim coating the wing with epoxy. Easy enough, I just cut out sqeege's from mt. dew boxes, & spread it thin.

Cut out the battery/ electronics area, used a plunge router bit on the end of my cordless drill, was afraid to use the mini router, that basturd spins too fast.

Cut out the tail surfaces & mounted them Up. I'm gunna have to put something over the holes in that color plast crap, maybe just some packing tape.

Oh, my one proud moment of the night,, my motor mount. I thought about it for a while, how to get the motor hooked up back there, so I took the lid from a 20 oz. mt dew bottle, ( can ya tell I'm addicted to that stuff?) trimmed off the little lip on it, then pressed it against the foam to leave a witness mark of where I wanted it to go. Then I took my hobby knife & made a cut a little over !/2 " deep into the foam. Then I screwed the lid into the foam, checked the angle, pretty close to what I wanted, then Unscrewed the lid, added some epoxy & screwed the lid back into place. That's my mounting plate. Used servo mounting screws to screw the motor baseplate to the lid, done. Then just cause I had ta get a look for what the plane might look like when I finish it, I mocked it together, which is nice about the low wing design, just sat the fuse on the wing.

So, tomorrow, aileron servo ( just gonna use one, this plane is really light, then two if it seems needed later on) , & ailerons, plus elevator & servo.

Quick question, they always say to lengthen the wires between the motor & the ESC or the battery & the esc? I think between the battery & esc. I'd prefer the motor & esc though, little wieght as it is, I'd like to use the esc to help counter balance the motor weight.

Although, that motor will only pull 15 amps maxed, battery gonna use can deliver 15 continuos , 18.75 bursts,, and using a 30 amp esc, dunno, whatcha guys think, which wires should i make longer?

ktaylor

oops forgot the pics

bdavison

My Feedback: (1)

Another tool that works even better is a Surform tool. Its basically a cheese grater looking tool used for wood, and surfers down here use them to shape the boards before glassing them. It works great on foam, and leaves a nice clean finish.

ktaylor

bd,
thanks for the tip. I think I've read about people using that on foam, forgot about it. I'm sure at some point I'll do another foam plane. I have a design in progress, been thinking of foam/ carbon fiber construction for that one. OK, off to install elevator & ailerons.

ktaylor

I now have the ailerons installed. I still have to install the snake tubes through the foam in the wing, that should be fun. Just playing with the weight balance of the plane, i figured out that getting the balance is going to be kinda hard. I'm going to have to make the wires between the motor and esc longer, gonna need every bit of wieght as far forward as I can get it. With an airfoil this thin it won't have much of a pitching moment, so that means the c.g is gonna definately have to be in front of that 1/3 chord, don't want a backwards stall.

so for the hinges, I used some dubro nylon plate hinges for 1/2 A planes, ( i think that's what it says on the package,, maybe its 1/4, can't remember. Kinda thinking that I need to add one more hinge on each side, that balsa has a lot of flex to it. So, I notched out the balsa & cut a groove into foam, then epoxied the hinges into the balsa, then after that cured, then mooshed some epoxy into the grooves in the foam & slid the hinges into them. For the control horns, those are du-bro's also, same scale, the kind that uses a plate under the control surface to sandwich it between the lower plate and the horn base with some tiny screws. So, hopefully tomorrow night I'll have the elevator finished & the serov in for the ailerons & snake tubes also.

ktaylor

ok, ailerons installed, wing epoxied to bottom of place, aileron servo installed, ( only one, just used a t horn with it) , been playing with prop combo's, 7 x 6, 8 x 6, 5 x 5, 6 x 3, and two 5 x 5's stacked, that kicks out a lot of thrust. I'll post new pics tomorrow. Gotta get my arse to bed.

ktaylor

OK, so, i haven't posted much progress, and to be honest, I don't think I'm going to continue with this thread or even with this plane. I had the plane balanced otu to where the "instructions" said to, and it was still way to tail heavy, i tried flying it today and no sucess, well, except for the last try which gave a short flight. I'm just going to copy from the other thread I post on, don't feel like typing it all again.

I'm really really not impressed with the design. It's almost impossible to have it not be tail heavy. The instructions, if you can call them that, say to have the c.g at 2.25" from leading edge of the wing. That's at 37.5% chord. Well, i had to add 6 split shot sinkers to the nose of the plane to get it to that point, and it's too far back. Tail heavy big time. Thing flopped over on it's back. Good thing that there was plenty of soft half melted snow on the ground to cushion it. So, I tried launching it with a little down trim, too uch, boomp landed upside down. ok, less down trim, straight out for 10 feet, went vertical for 6 inches & then flopped end over end until plopping onto it's top again. ok, try again, oops, look the vertical stabilizer came off, oh well, not using a rudder anyhow, ailerons will work, gave it some nuetral trim since there's less wight on the arse of it now,,, um, went out a little ways, climbed really well, tried to turn and, flop flop flop flop, plop onto its top into the snow. hm, ok,, lemme see, oooh look pretty, that looks a lot like one of my ailerons, hey it is,, ok, well, heck, the plane's disintegrating,, hee hee, ok, one aileron left, elevator is still good, aileron will at least spoil lift on one wing, & increase as well, h*ll, not like it can fly anyhow, why not. ( oh, & I was giving good hard throws with full throttle too) so i try one more time, full throttle, contorl check, why bother, throw it, out it goes, hmm still going, kinda quick even, getting faster, ok, pull up a little, WOW it goes into very small very fast loop, come out of it 8 ft off ground starts to enter a second loop ok, go a little nose down, HOLY &^^%&^&^^ inverted loop, maybe 5 ft in diameter, try to roll it out of it, ooh crap, only have one aileron, plop into the snow at WOT updside down. All of that last launch/ flight (?) took place in maybe 15 seconds. At that point, i realized it was time to go before I damaged the electronics, the foam was only $20, the electrics were a lot more than that. SO, i'm at a point where i got no clue what I want to do with this thing. I think I'm gonna go back to work on the P-51 for now, put a little thought into what to do with bd-5 before i do anything to it. Glad I didn't put the effort into painting it.

Loubud

Hey Blisters, Sorry to hear about the BD. Mebee you can make another one with a lot of mods. Screw the instructions. I modify everything.

ktaylor

Here's the final report onn the bd-5. It is now in peices. Or maybe chunks would be a better description. With all of the wedding stuff finally coming to a close, I was really ready to vent but didn't know it. I had the plane re-balanced to a c.g. of 30% chord, elevator servo mounted ( i borrow both servo's for another plane) and just could not for any reason get the aileron servo & contols wires to hook up right. Messed with it for 1/2 hour or better, then just had enough. Stood up, at the plane on the floor & stomped it into submisson. End of cheap junk plane. I generally don't do that sort of thing, but I've been kinda stressed & didn't realize it. The servo * motor survived my tantrum. I checked them out, passed ok. I saved my contol horns & hinges, pitched the rest. I might make another from scratch some day, my own design, better than what they came up with. So for anyone thinking of getting this plane, I would definately not reccomend it.

Loubud

Any pictures?

ktaylor

I'd have to go dig it out of the trash can out back. Too cold today. Sorry.

Loubud

Ken,
Go outside, chop some firewood and when you work up a swet, dig in the trash. Someone walking by might give ya some spare change if you wear old clothes.

VULTCH

It is so good to "vent by destroy" method. I very seldom do it, however I found some planes just won't fly. If I don't destroy the thing usually end up trying again after a few months only in failed attempts.
Great Post! Thanks for the warning. I only wish it had worked for you.

Vultch

m.prayad

my micro jet bd-5 building by fome sheet 3 mm my web site www.a-prayad.com http://www.a-prayad.com/index.php?la...=20300&Ntype=2

archer7153

Prayad do you have any plans for you BD5