zarx

WOW....i would personally congratulate anyone that would be able to control a DF by manually controlling the speed of each rotor. Imaging the hand-eye co-ordination for that to be done!!!
*in an aging mans voice* "When I was your age, we never used those fancy gyro-whachamacallits. Give me a receiver and speedcontroller...those were the good ol' days!"

Spaceclam

if you have it set up right it can be flown without the help of a gyroscope. however that is tough to do and the gyros help a lot anyway.

balsabuster2003

Has anybody looked into the possibility of using a good flight stabilizer like the "Co-pilot" availible at www.fmadirect.com ?

Spaceclam

I thought about it but you have to center the sticks in order for it to take effect. the entire idea of the gyros are to help smooth it out and make it a bit more controllable rather than to fly itself with the sticks centered

cpquit

hi guys.....!!!!

you people encouraged me a lot. i want to take up this project. but i dont have enough knowledge about electronics. i would be thankfull if somebody can help me out.

danvel

This is My DF.
I like the water bottle solution for the case because is lightweigt and pretty resistant. I'll put the batteries at the bottom so it's a little more stable. I'm still waiting for the batteries and I have 1 Gyro installed (not enough to fly I am afraid).
Total weight with batteries is going to be around 650g and total current is only 6-7 amps so I'm using Li-Poly batteries.
I have a question for Spaceclam (another one) Âżwhat's your distance beetween 2 oposite rotors? Do you think this has an effect on stability?

danvel

This is in answer to ZARX.
I use the timer interrupts to control the mosfets (TOC1-TOC5). As there are only 5 I use one to turn all mosfets on and the other 4 to turn them off one by one, this gives a very good resolution (I use 500 points) at 1 khz PWM frequency. Ask me If you need more details about my design.

Spaceclam

the distance is approximatly 26". this wil have an effect on stability but it will also reduce control rates but increase effectiveness.

ADI

Hi Guys,

I've been busy designing my DF. Took Spaceclams advice and bought GWS EPS-300C-C 5:1 motors and Todds models matched pair 10 x 4.5 props. Did some tests with 7.2v ni-cad pack and found this combination of motor/prop would lift a maximum of 135 grams plus the weight of itself (motor/prop) which is 67.75 grams. So 4 motors/props will lift themselves plus 540 grams. My 7.2v ni-cad pack weighs 300 grams. This leaves 240 grams for everything else. Once we use up the 240 grams we have no lift.
Specs for this motor say it has thrust of 301 grams with a 10 x 4.7 prop and 7.2 v supply.
So my 10 x 4.5 props are able to lift a total of 202.75. This ain't quite 300 grams is it ?
Could the 10 x 4.75 props make up the 98.25 grams difference ?
Anyway ... these figures might be usefull to someone.

Cheers ADI

Spaceclam

go to 8.4 volts. you will notice how much more lift you get and the lift gained is far more than the weight of the extra cell. however you will probably need some heatsinks. with those props i have each motor pulling slightly less than a pound.

cpquit

hi guys....!!!

you people encouraged me a lot. i am interested in taking up this project. But i do not have enough knowledge about electronics.
i would like to how to control 4 motors at the same time. people say it would be easier if i use piezo gyros, can i buy those indivually and install those. if s, how? is there any other way that i can control without using gyros. also, can i get the electronics parts of DRAGAN FLYER like processor(circuit board) to buy? plz help me out. plzzz


thnx.

Spaceclam

i have to be quick here. cpquit, you are in for an interresting project but it is fun. Some people preffer one way, others another. do you want me to walk you through it or just explain the necessary controls and let you have all the fun? i dont want to keep you asking questions but i do not want to deprive you of any of the fun of this either. (trust me, it is the best, most enjoyable waste of time i have ever experianced)

ADI

Spaceclam ....... you're pulling just under a pound each motor ?
Geez one pound = 453 grams. That's more than double my 202.75 grams.
That would mean that one motor could lift itself plus my standard 300 grams 7.2v ni-cad racing pack plus an extra cell all by itself. Something's wrong here. One extra cell couldn't possibly more than double the lifting power, could it ?. I gotta check my voltages and current draw. I'm assuming we have the same motors/props. ie. EPU3753 (370 motor) 5.33:1 gear ratio MPI Maxx Products Inc. ex Todds Models plus Todds Models CW/CCW props 10" x 4.5"

Cheers ADI

cpquit

thanks spaceclam for ur reply..

i dont want to do this thing just for fun, i want to take this for engg. final year project. because i am doing aeronautical engg(mechanical stream) i do not have enough knowledge in electronics. thats why, i want to buy the electronics part of DF. i surfed a lot to find the electronics details of DF but didnt get it enough. so please help me..

thnx.

ADI

I wouldn't suggest anyone attempt to build one of these unless you're either a seasoned RC dude an electronics engineer dude or an aerodynamics engineer dude.
The other requirement is that you have to be obsessed with this project and have the funds to waste on costly mistakes due to ignorance. I'm an electronics engineer and believe me, this is taking me a hell of a lot of time to design and test. Just sourcing some of the components is a big job.
One other thing - you also have to be nuts ! But ain't it fun ?

Cheers All
ADI

Spaceclam

i was neither o fthose things, and i did it. i am only 14. i said just under 1 lb per motor, and yes 8.4 volts will make that difference. also, because it is a nicad it will be running a good 9.6 at full charge. as far as electronics go, you need a coupla motors, (check the stats on them) you need a receiver, 4 speed controllers, if you like, 2 gyros, and 3 veetail mixers unless you can design a circuit yourself. the little $13 ones have far too poor resolution. the only ones i have found that work are the $55 ones from veetail.com. before you start building or buying anything you need to come up with a target weight and shoot for it. your thrust should be at least 50% greater than your weight, preferable 100% greater. the solution is reducing weight, not adding power. use as much composites and plastic as possible because it is very light. it is easier for me to answer specific questions rather than try and answer it all in one post. it would be extremely long, difficult to read and it would consume a lot of time to write.

Spaceclam

Ok. Now that i have a bit more time i can go into greater detail. I ams sure you are familliar with radios and receivers and such, so i will move to the veetail mixers. A veetail mixer takes two signals, one through a master imput and one through a slave imput. There are two wires that come out. One of them will be the master imput + the slave imput, and one will be the master imput - the slave imput. So if you had a master of (a random number) 5, and you had a slave of two, one output would be 7 and one owuld be 3. When you average the two values you get 5, the master imput value. This is the case for any set of values that comes through. So lets say you hooked the master up to a throttle channel, and the slave to an aileron channel and place the motors you are controlling with them on opposite ends of the model. When you increased the throttle, both motors would speed up. When you slave imput, one motor will speed up and the other one on the other end will slow down. This will cause your model to tilt, but your average throttle comes out to be the same. (this is assuming your throttle curve is linear, there are always other factors at work but you get used to them) and this will allow you to vector tyhe lift of all motors in the direction you move it while still maintaining the same amount of thrust (prop thrust not upward thrust) and also keeping your motor torque the same.

If you wanted to control both aileron and elevator, you have to split up the throttle chanel, one going to the master of each veetail and elevator to the spare slave channel on your new mixer, and you have control of both aileron and elevator.

That is all great, but what about rudder? i will have to go into a bit of detail here. If you want your model to stay pretty much locked in facind one direction, you have to have counter rotating props to counter the torque of eachother. You put one pair (both clockwise for example) on opposite ends of the model, and then you put your other set (counterclockwise) on opposite ends but perpendicular ot the last set creating a "t" shape (not an x. there is a difference) So if you want to control yaw (ruder) there are two ways. One way is to have gimbals on each motor but that is pretty heavy and complicated. Two, you can speed up one set and slow down the other one, causing a torque imbalance and making the model rotate one way or another. too much of this will cause the model to become unstable and should be used as a trim, not a main control. Below is a wiring diagram for what i am trying to say. In oprder to accomplish that, you have to put a veetail between throttle (master again) and rudder (slave) and hook up the masters of your other two veetail mixers to the outputs of those. There will be four output leads and each one will go to it's own speed controller and in turn, a motor. The two leads that come off each speed controller should have their associated motors placed on opposite ends of the model if you want your model to be controlled. If you want to gyroscopically stabilize your project, lets say for elevator and aileron, you have to put the gyro inbetween the receiver output and the veetail mixer because that way it will mix it in to the control of the axis.
If you have any questions, please let me know and i will help to the best of my abilities. it's cool to see so many people across the world doing the same thing, something considered unusual that turns heads everywhere. cpquit, i would not buy the df electronics simply because if something goes awry (especially considering this is experimental) you are out of luck. i would suggest doing it this way so if something happens you can replace one component quickly and easily and it will cost less to replace too.

ADI, here is a link that shows the thrust data for this motor with various props. the gws props they use there are very close to the todds models props, but the todds models ones produce slightly more thrust i have found. http://www.balsapr.com/catalog/motor...ductId=T350628

ADI

I gotta say - you are an exception for a 14 year old and you've been a great help to me and I'm sure - others posting on this thread. Many thanks again for the info.

Cheers ADI

Spaceclam

Thank you, but i have to put the credit tward my obsession. when you are as obsessed as i can be, you will find a way to get it done. i hope this information passed between us as modelers will help anybody who wants to take on a project like this one. It is a fun little project and i like to encourage as many people as possible to try it. lately i have been working in close contact with a design team from purdue university attempting the same thing. It's fun to spread the vtol fever around. ADI, have you finished your vtol yet? if so would we get some pictures? maybe in flight?
Cheers

cpquit

hi spaceclam u r really exception!!!

anyways thanks very much for the information.

that will help me a lottttttt.

thnx very much again...

Spaceclam

any time. any problems just let me know
cheers

ADI

Hi All,

Spaceclam ...... will certainly upload pics when it's finished, but I'm still working on the electronics at the moment. I've got all the hardware now, including carbon fibre rod - archery arrow shafts to be precise. http://www.goldtip.com
Spaceclam , did you make your own heatsinks for EPS motors or buy them ?

Cheers ADI

F1992

My Feedback: (4)

TO: SPACECLAM.

Sir,
As i understand you are Big Profi in this area. It is fact.
Therefore help to dilettante.
(I send E-mail, but I don`t sure that I did all correct)
Problem.
Need "tractor" prop w/COUNTER clocwise rotation.
GW= 2 lb/per. prop. RPM ~10000. HP 0.5/per prop.
DIA of prop 10-11"
What can be thrust? According to program thrust have to be ~3lb. But I confused, because "pitch" don`t including in program.
Thrust=F{RPM; DIA(prop)}
You mentioned about counterclockwise prop <www.toddsmodels.com>
There is only one size. Is it correct? or you can to recommend else info.
Wha do you thinking about to use blade w/simmetrical profile?
What can be effect if to use blades of DF-$ by 10000RPM? What can be thrust.
Thank you before.
It will be nice if I received answere?
<[email protected]>
Regards.
GOD remember of nice people
Tell me that you thinking?

Spaceclam

F-1992, Check your emails. the draganflyer blades hardly withstand 3k let alone 10k. dont try it. until your pitch starts getting really high, your static thrust will be pretty much the same even when you change the pitch a little bit. there will be some difference but not much. i dont know much about thrust calculation really, but from my program i get anywhere between 2.8 and 4.2 depending on which prop you use. (both using the zinger props i mentioned in the email and the 4.2 lbs being the 11x4) but for vertical flight you want the lowest pitch possible as it is more responsive.

Pipefish

Hey Space,
you´re an example of perceverance and good will for all of us RC modelists.
Keep on the good work and best regards from your friend of Brasil!