theyalwaysland

I am thinking about designing and building some miro airplanes. I got into nitro airplanes 12 years ago and have designed and built some large stuff before getting out of the hobby. Now I am getting back into it after about 5 years and things have really changed!! i have always been interested in micro but could never get into it because of the lack of technology and cost----but now WOW! Its like a caveman seeing a rocketship or something.

Anyways the plane that I want to design will have about a 15 inch wingspan and a wieght (without electronics and motor) of around 15 grams. The problem is that there is WAY too many choices. GWS has like what 800 motors!! I need someone to give me a package that will work for this.

My dream is to have a acrobatic plane with about a 18 inch wingspan--but a want it 4 channel--is this possible? No foamies!

micro_builder

My Feedback: (1)

firstly, welcome back to RC!

you're right, there's so many options these days. when i first started getting into it and had to buy micro equipment, it took me over a week just to decide on the basic parts. for what you're wanting, slowfly.com has some new stuff thats pretty cool. a 2 gram RX that can have up to 7 channels, and can opperate actuators or servos, brushed motors, or brushless motors. and speaking of brushles motors, they've got a new line of BL motors with some serious power for very little weight. there's lots to absorb on their site, but its certainly worth looking at: http://www.slowfly.com/index.chtml you can also get their equipment, and pretty much everything else (micro or otherwise) here: http://www.bphobbies.com/view.asp?id=V979410

with an 18 inch span you could certainly have yourself a fully functioning 3D aerobatic bird in your hands...just depends on how much you're willing to spend

if you dont want to go brushless, the new N20-ULV motor, geared 4.2:1 with a GWS 5x3 will give you over an ounce of thrust at only 1 amp. with a GWS 6x5 prop, you can get over 39 grams of thrust for 1.6A. those are pretty good numbers for a 12 gram brushed motor. if you want to go that route, look for the Kenway gearboxes for N20s, they're geared with the 4.2:1 ratio. a kokam 145mah lipo would give you an amp, but flight times would be short. an E-Tec 250 or similar would probably be a better choice for a few more grams. slowfly has some new cells that can pack a punch too. its certainly a cheaper route than the BL motors.

if you're wanting true 3D flying abilities, you'll probably need to go with servos. but, servos are getting lighter every day, down to 2 grams and less. 3 grams is pretty average these days. if you're wanting something that'll just do some fun loops, rolls and other stuff like that, you could probably get away with some beefy actuators (1 gram or heavier should do it).

what kind of plane are you gonna go with?

nick

theyalwaysland

The smaller plane will definantly be a high wing-trainer type. The other will be a mid-wing plane. Probably a knock-off of a nitro plane that I designed and built some time ago. I would like to get the power packages down and then biuld the plane around the gear. I would rather have too much power than not enough! My first electric plane experience was about 7 years ago with a 6v speed 400 motor on 6 cells powering about a 2 pound plane. I was NOT impressed. The plane never got more than 50 feet away from me before hitting the ground. And it was not because of design or piloting error---NO POWER!!!

I have another question---can I get a system to work with my existing 72 mhz transmitters? If anybody can give me an exact system that would be great. I am hoping to spend under $400 per plane. Possible?

I will post some pics of my planes when i get them done micro builder. Oh yeah, I tried the whole biuld my own from the aero hogs aero ace thing, but after several plane I quickly learned that the whole twin moter thing can be a pain. Exspecialy to trim out such a small plane with two motors! Plus I like the whole elevator,rudder,alierons thing.

Seek and Destroy

you should be able to spend under $400 for both planes!

micro_builder

My Feedback: (1)

you'll love electric flight, the advent of lithium batteries has now made electric power actually rival nitro power. not to mention its allowed some folks to make fully functioning micro airplanes that weigh less than one gram, ready to fly!

the slowfly equipment in the links i posted (microbatics) function on 72mhz, so you could use your current TX no problem.

and yeah 400 bucks could get you the top of the line in micro electronics. this package right here is meant for micro 3D airplanes, so its all ready to go: http://www.bphobbies.com/view.asp?id...95&pid=W702234 if you're wanting to stick with GWS type stuff, it'll be even cheaper and bphobbies.com has a bunch of flight packs to chose from. slowfly.com also has a little deal where you can make your own package to suit your needs perfectly. its crazy that some of those little BL motor can put out over 60 grams of thrust when they weigh around 5 to 10 grams only.

yeah trimming micro planes is an art. i made the same plane at least 4 times and it wouldnt fly, and all it turned out to be was the rudder wasnt centered properly, it was only off by a millimeter or two and it would totally throw it off into a spiral immediately after launch. thrust differential can be just as big of a pain, but its worth the effort when they do fly!

are you familiar with the Ultimate 3D plane? if so, i've got a .pdf plan for a Micro Ultimate, same plane, just scaled down to 9.5 inch wing span. if you want it, just let me know and i can send it to you (this site doesnt allow uploading of .pdf's for some reason).

nick

theyalwaysland

Yeah, I would love to see any plans that you might have for this type of airplane. What about covering? Do you guys use the same kind of stuff that is used on the Lazy Bee type of planes? Its some kind of tissue that can be ironed on. I can't remember the name of it right now. I would like to use transparent monokote, but the wieght is a major negative.

micro_builder

My Feedback: (1)

alrighty, i'll shoot you an PM. as for the covering, most use just plain old tissue paper, the kind thats meant for packages or decoration. you could buy some in whatever color and do it that way, or you can use some graphics and print it onto the tissue (i've got some graphics for it already that i can send you also). the tissue doesnt weigh enough to cause any issues. i've always used Elmers spray adhesive to apply the tissue, it lets you reposition the tissue if you need to, but it'll hold it tight once you set it.

i used some new foam thats come out called cellfoam 88, thinnest type they cell is 3mm. its thicker and heavier than i liked, but it worked well enough. it was the first time i made a real plane with foam, and i learned quickly that i'll always be a bigger fan of balsa! although, it does hold up a LOT better to crashes than balsa.

i attatched a pic of what the plane will look like with the graphics that come with the .pdf and there's a bare balsa version on the first post here http://www.rcuniverse.com/forum/m_4263429/tm.htm when i was building it, i forgot to add the graphics to the bottom wing and rudder *d'oh*

nick

Neurotex

Sharp plane! She needs a little pilot... maybe a Tazmanian Devil with goggles.

I've never tried the Elmers spray before. Sounds like I should since after
a few hours of breathing that Butyrate dope I start getting alittle goofey.
That can't be good.... especially when I start air brushing the stuff.

Speaking of Butyrate. Appling a very thin coat to balsa can give it strength
to where it holds up better than foam. Not sure if it will add more weight than
what you want (depends on how much you thin it) but I prefer the balsa
over the foam. Foam is quicker but I'm finding it cracks easier. Usually just
above the glue joint. It melts too when it comes in contact with Butyrate so
it has to be masked off if I airbrush.

micro_builder

My Feedback: (1)

neurotex, the elmers stuff is great. i had tried a differant spray adhesive at one point, but it was much heavier, and stickier - a serious pain to work with. the elmers craft bond is a lot better, cheap too!

i still cant figure out why i cant upload the .pdf files. i've done it before in other threads, but lately it wont let me.

nick

Seek and Destroy

they probably updated to where you can't upload pdf files.

Gigaah

For something around an 18" Wingspan GWSs smallest stuff should do eh?
www.aeromicro.com

I got 2 servos,RX(4 channel),ESC(lipo compatible),motor/prop there and the battery at common sense RC. I paid just about $100 and its all standard 72mhz. I think all that gear weighs about 60grams. You could pretty easily shed 10+ grams with 3.6g servos and lighter battery. But it will cost just a bit more. I paid around 100$ with two batteries.

micro_builder

My Feedback: (1)

yeah the GWS stuff should work. if you can get the electronics weight, battery included, you'll be able to figure out how big or small of a plane you could go with. 18" should work though. either way, i think going to lipo power would be the best thing to do, after that, its just a matter of making it all lighter.

nick