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Tuesday, November 17, 2009

Friday, May 1, 2009

Common RC Heli Control Configuration

Co-Axial Heli
Co-Axial helicopters use a counter-rotating twin rotor design. Two sets of blades spinning in opposite directions eliminate the need for a tail rotor and provide excellent stability making these helicopters an ideal introduction to the hobby.

Collective Pitch (CP) Heli
Collective Pitch Helicopters alter altitude by changing the blade angle using pitch servo combined with increased RPM from the motor (pitch/throttle curves decide the exact input of each variable and can be altered depending on ability).

Fixed Pitch (FP) Heli
Fixed Pitch RC Helicopters only have 4 channels and they increase in altitude by increasing power to the motor. They have curved blades to create more lift and lack the collective pitch (blade angle) method of lift. They have a very simple servo configuration making them easier to repair than a CP Heli.

Saturday, April 25, 2009

EVO 12 Troubleshooting

Recently, my faithful EVO 12 decided to give up on me. Here are the symptoms. The right stick (for elevator & aileron control - I'm a mode 2 user) fails to respond. If you go under the Servos -> Monitor menu, both CH 1 & CH 2 show the bars in 100% end-to-end position. Similarly no respond by the right stick movement, but left stick movement shows the bar responding accordingly. I suspect to be the 74HC4051 chip or the Micro Controller (CPU) that is having problem.

However, thanks to Mike from http://www.modelradioworkshop.co.uk/index.htm.

Here's what he said.

The earlier production of the Evo's did have a problem with the wires to the stick pots, but this tended to only effect the horizontal stick pots. If your transmitter pots wire include yellow as the middle wire on the horizontal pots then this suspect wire. All of the main stick signals go to the main CPU chip, so I don't think it will be the 74HC4051 chip. I suggest that you measure the voltages at the pots it is around 3.28 across the pot and a centre voltage of 1.8 volts. Don't forget to remove the RF board from the transmitter so that the RF doesn'teffect the DVM reading. If that seems OK, I would then check that the voltages appear at the plug and socket for that stick on the main board. If that all seems fine then it's possible that the model data have become corrupt, so you could try sending a blank models data to the transmitter. Which is like resetting the transmitter to factory setting, this is available in the data manager program which you can get off the Multiplex web site.

All the hardware checks show things are in order & hence I tried reloading the software as recommended by Mike. However, after several software reloading tries, something new shows up. Like the Welcome Tone on powering up is now gone and the EVO keeps going into the Servos Menu after start up.

Luckily with Mike's advise again.

From what you are saying, it tell me that the transmitter has lost it's stick and slider calibration. Here is the proceeded to re-calibrate the sticks and sliders.
  1. With transmitter off centre all of the sticks and the sliders.
  2. Switch the transmitter on and then move each stick in turn to one end of its travel and wait for the LED by the ON/OFF switch to go out. If the transmitter tells you to move the throttle stick low, as you switch on make this the first stick to be move to its end of travel.
  3. Do the same with the 2 slider controls.
  4. Once you have completed this operation use one of the digi knobs to get out of this menu by dialling out to exit until you get to the normal display. The voltage level will show 0 volts at this point.
  5. Now switch off the transmitter and the calibration data will be stored.
  6. When you switch the transmitter back everything should be displayed as normal i.e. voltage and trims etc. If the transmitter goes back into displaying the stick data i.e. percentage numbers it means that the calibration was not completed or not done correctly.
And Walla! My EVO problems are solved & it works just as fine as it did before. My sincere thanks to Mike!

Saturday, March 14, 2009

ClonePac for Futaba Radio

A simple to built memory add-on for Futaba Radio. This is a cheap, simple & effective circuit to expand the memory for your radio which you can built over a weekend. To make fabrication even easier, you could consider using a veroboard instead of etching your own PCB.

Sunday, March 1, 2009

The Wall

What it is
The Wall or the Pop-Up: is when the airplane comes to a stalled stop into a vertical position from a horizontal flight path.

Plane Set-up
Full 3D Throws.

How to do it
Enter from level flight into the wind with power off. Pull full elevator, neutral on the elevator as soon as plane is vertical. You can also enter from inverted which is one variation. Another variation is the Wall Slide, which enters going downwind...you, can actually maintain altitude for a few seconds without throttle while the wind slides the plane down the runway. You can also do a Wall slide with a twist. As the plane slows down in the vertical position, add rudder to make the plane spin around heading back into the wind.

Trickiest Part
Don't over rotate. The idea is a vertical stop.

Recovery
Full power climb out.

The Terminator

What it is
It’s when the plane is flying straight and level and then makes a 90 degrees dive straight down toward the ground. When the plane gets close to the ground, you pull up.

Plane set-up
Full 3D rates.

How to do it
You will start out by making a straight and level pass down the runway. This maneuver can be done from a lot of different altitudes. To start out you need to be pretty high till you get your timing down. Speed is something else that you can play around with to do different variations. It looks better at a slower speed. After you have established your speed and altitude you will give the plane full down elevator. This will make the plane dive straight toward the ground. Let the plane come down to where ever your comfort level is. You will then pull full up elevator and add power. Once you have mastered the basics of this maneuver you can play around with different variations.

Trickiest Part
Getting your timing down to just when to pull out.

Recovery
There is really no recovery from this. You either do it great or hit the ground hard.

The Roller Coaster

What it is
Plane is rocking back and forth from full up elevator to full down elevator diving straight to the ground.

Plane Set-up
Full 3D rates

How to do it
Take the plane up to 100 - 150m of altitude. Bring the plane to a complete stall, as if you are doing an Elevator. This maneuver will be done with low throttle. You may need to give short burst of power to help control. Once you get the plane in an elevator you will be giving it full up elevator. You will then need to reverse the elevator input to full down. You will continue to reverse the elevator inputs pausing a little to let the plane get into either an upright or inverted elevator. Hold this till the plane reaches the ground. This is when you will decide to exit the Roller Coaster either in an inverted or upright Harrier.

Trickiest Part
Getting the timing down and keeping the plane straight.

Recovery
Full throttle, and slowly release some elevator.

The Yo Yo

What it is
This is an upright Water Fall. There are a lot of variations with this maneuver.

Plane Set-up
Full 3D Throws

How to do it
From a Hover, power out vertical. After the plane has reached 30 to 50m, pull power back give full up elevator and give a short burst of power. The plane will flip around into an Elevator. Let the plane fall back to the ground and power up and do it again. This maneuver looks best doing it two to three times making the loop smaller and lower each time.

Trickiest Part
Getting the plane to flip over into the Elevator position when you are doing it low.

Recovery
Full power, flight out straight.

The Snap Up

What it is
The Snap-Up is when the airplane comes to a stalled stop into a vertical position from a horizontal flight path with a snap-roll in the middle. This is very similar to a Pop-up or Wall.

Plane Set-up
Full 3D Throws.

How to do it
Enter from level flight into the wind with power off. Pull full elevator and full right aileron at the same time. (Neutral on the elevator and aileron as soon as plane is vertical) The plane does a snap roll into a wall basically.

Trickiest Part
Don't under rotate. If you do the plane will be pointing nose down toward the ground. That's not good unless you have plenty of altitude. Practice this up high until you get your timing down. This is a real crowd pleaser when done correctly.

Recovery
Full power climb out.

The Panic

What it is
The Panic or Blender maneuver is a vertical diving roll that virtually stops its descent as it instantaneously enters into a flat spin. Presented at TOC 1998 and named by Blaine, I designed this maneuver always looking for the highest performance at what it is called surprise factor and I remember it did work very well. You climb high, guessing 300 feet idle and punch down to a perfect vertical line, add some left aileron to do a kind of slow rolls during that dive. Then when you reach an altitude that is good for you, the airplane will suddenly go to a flat inverted position.

Plane Set-up
Simple, nothing special here, you need to go to your set up that you use to do the 3D aerobatic, so high rate a a lot of deflection. I recommend you to have at least this numbers. Rudder 45 degree, elevator 40 degree, aileron 35 degree. If you can go for higher number it will be better because the quick spinning will be quicker and tighter. CG does not need to modify for this maneuver, I found a bit better when the CG is on the nose heavy for 3D aerobatic.

How to do it
Climb as I explained before, make sure before you push vertical to have all at high rate, this is important to avoid crashes!, so dive rolling slow left and when it is the time to spin, use this technique, full down elevator, full right rudder and full left aileron, this is the best sequence too. This sequence needs to be done continuously, this means as soon you reach full down you go right rudder and as soon you get with the rudder to full go with the aileron. All the movement of your thumbs needs to be quick. This is a very hard maneuver for the airplane and you actually can bend the wing tube! Or if the wing it is not strong enough even worse you can crash the airplane! so to reduce the G's when you decide to do the spin go with the sticks slower to the full position, this will make the airplane to start to spin with less angle of attack loading less the airplane. If you feel you putting to many G's to your airplane try this sequence, full aileron then full rudder and elevator at same time, but the rudder and elevator should not go so quick to full stick position, go a bit slower. Once you see your airplane it is spinning flat open the throttle to full position to increase the spinning and to maintain altitude, keep the power at that position till you feel the airplane wants like to fly out of the spin. From that inverted flat spin you can do any thing you want!, like go to a torque roll, Cobra, etc.

The Waterfall

What it is
The waterfall is a maneuver where the plane pivots 360 degrees in the pitch axes with very little forward motion and altitude gain or loss.

Plane Set-up
The primary control surface is the elevator followed by the rudder and finally the ailerons. The control rates should be set for maximum deflection, not that you will need that much, but it's a good place to start. Later, if you find that you’re consistently not using max to do the maneuver, you can dial some out. Remember the plane will be VERY sensitive in these rates. There's two ways to manage this. One, is to have dual rates, the other is to have a lot of expo dialed in to make the plane less sensitive around the neutral point of your radio.

How to do it
The waterfall is a fairly easy 3-D maneuver to learn. There's two ways to enter. One, from a harrier, the other is from just above a stall. Let's start from just above a stall. From a safe altitude, slow the aircraft until you feel that it's at it's slowest CONTROLLABLE speed. When the plane is directly in front of you, push full down elevator and apply enough power to rotate the plane 360 degrees back to the upright position. How much power? That will depend on the type plane and engine. Start by using full power, after a while you will be able to tell how much it actually takes to get the plane to rotate.

Entering from a harrier will basically the same. It's actually a little easier because the plane is in a nose high attitude and will have more momentum as the nose comes down on the rotation.

Trickiest Part
The hardest part is keeping the plane from falling off of one side or the other. The rudder is the most effective control having the most air moving by it because of engine thrust. The first few that you do, the plane will probable fall one side or the other. Use rudder opposite to the fall to keep it upright. Ailerons help some, but remember, this is a 3-D maneuver and the plane's not flying. There's very little air moving over the wings so the ailerons are not very effective. The other tricky part is stopping the plane as it comes over the top. You can either fly out by releasing the elevator and keeping the power in, or go right into another by not releasing the elevator. With practice, you can get the plane to make consistent small tight circles in a very small space.

Recovery
This is a pretty safe maneuver if you keep enough altitude. The thing to remember is, THE PLANE'S NOT FLYING! If you over rotate the nose pasted level and want to recover, first get the plane flying by releasing the elevator and keeping the power in. If you fall off to one side, again, RELEASE THE ELEVATOR, use ailerons to get the plane upright, and use enough power to get the plane flying.

Friday, January 2, 2009

The Elevator

What it is
The Elevator is when you completely stall the aircraft with a massive amount of elevator, either up or down, and it descends almost vertically down (Elevator) upright or inverted.

Plane Set-up
There are two things needed to do the Elevator correctly,.
1. The CG on the tail Heavy Side.
2. 45+ degrees of Elevator travel.
Of the two, the 45 degrees of travel is the most important to have. A straight Leading Edge wing will also make it easier along with having Counterbalances on the elevators.


How to do it
The easiest way to enter this maneuver is to go up a mistake or two high, and dive straight down. once the plane is pointed at the ground, after making sure the high rate elevator is on , pull full up, and hold it. Do not release it or hesitate when pulling, that allows the nose to come down and the plane will try to start flying again, then the wings will start rocking, and it won't look very much like an Elevator. If the nose comes up when you pull and then drops again, you can either add a click or two of power immediately after the pull, or move the CG back a little more.

Trickiest Part
There is not anything super hard with this maneuver, as long as the above is followed. Most of the time people will not pull and hold the elevator, and the plane tries to fly out of it, still at a stall though and then starts rocking the wings (PIN THE STICK).

Recovery
To get out of this maneuver, power can be added while releasing the elevator slowly and just let the plane fly out, or simply release the elevator, the nose will fall through, build some speed and gently pull out.

The Pogo

What it is
Hover that climbs and descends.

Plane Set-up
Normal 3D set-up.

How to do it
Establish your controlled hover. Make sure the plane is vertical and stable before performing. Apply power (3/4+) for 5 feet. Bring the power back (1/4-). "Fly" the plane back down the line. Apply throttle as needed, but in short bursts. Make sure the plane remains vertical on the descent.

Trickiest Part
The descent. Trying to fly the airplane backwards without any prop wash over the surfaces can make for some very uncontrolled times.

Recovery
Full power (away from anyone or anything). It's just like getting out of a hover.

The Torque Roll

What it is
Plane "Hovers" vertically in place, rotating left around its roll axis.

Plane Set-up
Full 3D throws in elevator and rudder are a must. An aft CG helps a little also. Some flyers will run their CG back to make this maneuver easier, however a plane that is balanced will Torque Roll just as good as one that is tail heavy. It all about getting the plane in the sweet spot. Once you get the plane completely vertical it become very easy. That is the hardest part is recognizing the true vertical plane. The pros will also tell you to add 3/4 degree of up thrust to your engine. This helps keep your plane from falling forward in the Torque Roll, and it'll fly straighter up lines in non-3D maneuvers, too.

How to do it
The easiest way to learn is to start by learning the "Elevator" and then the "Harrier". After you have mastered this it is an easy transition to the Hover. Once you can "Hover" then "Torque Rolling" is the next step. As your plane descends in an "Elevator" start adding power as your near the ground this will transition you into a Harrier. All you have to do from here is give a short burst of power and your plane should stand up vertically. Adjust throttle to keep the nose pointed up and make corrections with rudder and elevator to keep things straight. One thing to remember is that most planes want to fall off to the left and toward the landing gear. (Tip: Most of the inputs that you give are up elevator and right rudder.) The throttle curve is key for this maneuver. Set your ATV or Travel to the maximum %. You will then need to find a servo arm that enables you to open and close the carburetor completely without backing down your travel. This is getting your throttle mechanically perfect as you can get it. The next step is setting up your throttle curve. This takes a little time and patience but it is well worth the time and effort. The key is that once you find the stick position that the plane will hover, you want to set your curve so that your are hovering when the throttle stick is at half throttle. You adjust your curve from there as needed to barley let the plane climb or decent with one click up or down on the throttle. This really keeps you from fighting with the throttle and lets you focus on controlling the plane.

Trickiest Part
Recognizing your correction when the plane's belly is toward you. (Tip: Think push the rudder toward the low wing when the belly is toward you.) You have to be fast with throttle corrections. Most flyers add "bursts" of power, along with rudder/elevator corrections. If you simply hold full throttle, you'll climb out of the maneuver. One of the most common mistakes is giving wrong rudder inputs when the plane is belly in.

Recovery
Fly out at full throttle.

Airplane 3D Maneuvers

3D maneuvers are performed when the airplane is in a stalled condition. These maneuvers are done with the airplane at nose high 45-degree angles, at hanging on the prop or a tumble tail-over-nose gyro rations.

For a good 3D airplane setup, start with having lots of throw in the control surfaces and a very powerful and reliable engine. Sadly some airplanes just 3D better than others. The Edge & Extra are examples of good 3D models to fly.

List of common 3D maneuvers.

"The Torque Roll"
"The Pogo"
"The Elevator"
"The Harrier"
"The Waterfall"
"The Panic"
"The Blaino Draino"
"The Snap Up"
"The Yo-Yo"
"The roller coaster"
"The Terminator"
"The Wall"
"The Harrier Roll"