Friday, November 26, 2010

Harrier Tutorial video

I got a request for a tutorial on the Harrier. Here it is!

3D Harrier Training from Thomas Kitt on Vimeo.

The Elevator

The next maneuver that I'm going to go over is the Elevator. If you haven't read my article on the Harrier, please read that first, because I will refer to that article at least once in this article. Here goes!

The Elevator is a very easy maneuver to learn as long as you don't over control the aileron and rudder controls; everything else is pretty straight forward. First, start high. Start high whether you are a new pilot or not, because this is a descending maneuver.

So once you are up high, chop the throttle and let the plane slow. Then increase up elevator until you are at full up on high rates. The plane will most likely want to stall. If it drops a wing, add the opposite direction of aileron and rudder to correct the problem like mentioned in the harrier article.

The plane will most likely drop the nose as well, so to correct this, add a little bit of throttle. Just enough to keep the nose level or a little bit up; about 1/4 throttle should be enough. If you can get the nose up while doing this maneuver, it looks really cool, but don't get it above about a 20-30 degree nose up attitude, otherwise the plane will start to tail-slide and things will get ugly.

To exit the maneuver, simply add throttle and let off the elevator slowly. If you are exiting high, simply release the controls, let the plane stabilize itself, and pull out.

As far as CG goes for this maneuver tail heavy is the way to go. Refer to my article on CG for information on how to safely find a tail heavy CG.

Check out the video embedded below. I do many elevators in this clip, and transition right into a harrier or a hover. I normally do an elevater right after the maneuver called the "Enema" (yes that is its real name). An enema is that maneuver when I start inverted, pitch up at full throttle, then do a tumble and it exits spining upright around the canopy. (Doc invented that one)

I hope this has helped someone out there! Happy Flying!

3DHS Extra SHP Baby Don't You Do It! from Thomas Kitt on Vimeo.

Thursday, November 25, 2010

Tuesday, November 23, 2010

The Harrier

Hey Everyone! I recently got a suggestion from a friend of mine saying that I should go through each 3D maneuver, and explain a good set up and some simple tips to follow while learning to do that maneuver. After reading that suggestion I remembered that that was the original reason why I started the blog. So here goes.

The Harrier is pretty much the basis of most 3D maneuvers. This maneuver is probably the one you should learn first, for it is simpler than most of the others. Although I learned to hover before I learned to harrier, I think I should have done it in reverse order, because I never was proficient with anything but hovering until I learned to harrier. So if I had learned to harrier, I would have progressed into 3D a lot quicker and with less hassle than I did.

First off, if you are a new 3D pilot, be sure that you are using your beater airplane that has generous wing area, such as a 3D Hobby Shop Extra SHP. This plane is their "3D Trainer" and I highly recommend this airframe for any new 3D pilot. I own one too and love it!

Second, make sure you have adequate throws. If you are using the SHP, about 40-45 degrees on all surfaces for high rates is optimal.

Next is CG. Refer to my "Finding the right CG for 3D" article for tips on that.

Okay, now for what we've all been waiting for. If you are using a small electric like the SHP, there is a visibilty limit on how high you can go, but start as high as you can so that you still know where the plane is pointed. Then, since you are up high, pull the power back to about 1/4 throttle and let the plane slow. As it slows, don't let the nose drop, feed in up elevator. Now if the plane starts to descend, add power gently. Don't bang it wide open or you will over power it and end up climbing or doing a loop... and then it can get ugly... or worse!

Once you kind of get the idea for how your plane reacts at low speed, bring it down a little, but not too low. About 30ft should be okay. Do the same and try and hold your altitude with your throttle.

Now I'm going to give you a quick run down on the physics of wing rock. Wing Rock is the phenomenon that occurs during low speed high alpha maneuvers (like the harrier or elevator) when the wings rock from side to side. The reason for this is because each wing is not created equal, no matter how hard they try. One wing at these slow speeds will always stall first, so it drops. As it drops, it not only rotates on the "z" axis (aileron roll axis), but also yaws on the "x" axis (rudder). So the plane isn't just dropping a wing, it is also yawing in the direction of  the stalled wing.

So back to the wing rock topic, once the wing stalls and drops, it picks up speed, which turns into lift, and the wing regains flight. But as it regains its lift, the other wing has lost the airflow needed to keep it from stalling, and down it goes.

At first glance, your reaction would be to correct with just aileron. The truth is, although this will correct the rotation around the "z" axis, it will not correct the yawing action on the "x" axis. Correcting with aileron will make for a not-so-fun game of trying to correct aileron, and then randomly correcting heading with rudder. To make this easier, when the left wing drops, add both right aileron and right rudder; this will fix both problems.

Now, since the atmosphere we are flying in is not a controlled environment, and added in with factors like torque and drag, this system is not something to follow exactly. This should  be in the back of your mind when you are flying, and also should be used when needed. Since we face other factors like torque and drag, you will also need to correct your heading further than just moving both sticks in the same direction. So get to know your airplane, and don't bring it too low until you are familiar with it.

Now we get a little more complex with the harrier. Once you have mastered slowing the airplane to a harrier, going in a straight line, and then throttling up to pull out, you are going to want to do a harrier for more than just the length of the runway, so eventually you need to turn.

There is a system to the harrier turn, and it can be followed quite closely, but again, it's not fool proof.

Say you are going along in your harrier at about half throttle and you decide to turn. When first learning this, throttle up slightly and climb, then pull full up, give right or left rudder, and counteract the rudder with enough opposite aileron to keep the wings level. Upon entering your turn, gently reduce the power, and add down elevator if needed. The down elevator should not be held too long however, and will only be used to keep the nose from ballooning upward. When you've just about completed your turn, you will need to feed back in up elevator and throttle. You will probably need to apply some opposite rudder to stop the turn from spinning past your desired stopping point, and you will need to level the wings as needed.

I hope this has helped someone out there! Let me know how it works! Below is a video my my SHP. I do a lot of harriers with this plane because they are fun, easy, and it's a lot of fun to hear the rudder scraping on the ground!

3DHS Extra 300 SHP Huckin' with Doc Austin from Thomas Kitt on Vimeo.

3DHS Extra 300 SHP Huckin'

Hey guys! Yesterday I went over to the SPARKS field with a buddy of mine Doc Ausin. Here is the video I just made of yesterday's events. Check it out!

3DHS Extra 300 SHP Huckin' with Doc Austin from Thomas Kitt on Vimeo.

Monday, November 22, 2010

How to find a good CG for 3D flying

We all have wondered, "How do I find a good CG for all 3D maneuvers?" 

First, fly your plane at the manufacturers recommened balance point, and test to see if that is tail-heavy enough for the flying that you want to do. Most likely, it will be too nose heavy, and you will have to bring the weight back. The first thing you want to do to bring the weight back, is move the battery back little by little.

Next, if your battery is as far back as it can go, or as far back as you are going to let it go, test your power to weight ratio, and make sure that you will still have enough power to pull out of a hover and other maneuvers if you add weight to the tail. If you can, add weight to the tail, if you can't, try investing in a lighter motor/ESC to save weight in the nose.

Up until now this has pretty much been review, right? Okay, the main reason why I started writing this is so that I can say my philosophy for finding the right 3D CG.

When I set up my planes for 3D, I make sure they are as tail heavy as I can get them. I achieve this goal safely by moving the battery back in small increments until it can't any more; then I add one 1/4 ounce lead square at a time to the tail right in front of the rudder hinge line. I do this until either the plane will hover nearly hands off, or get squirrely in flight. If I get to the point where the plane gets squirrely in flight, and I have lead on the tail that won't detach itself from the airplane, I move the battery forward a little bit, and then mark the place on the battery tray so that I don't go back beyond that point.

Keep in mind that having an extremely tail heavy CG will make the plane un-precise in maneuvers such as slow rolls and other precision maneuvers. Try and find a CG that works for both, or mark your tray in two places: Extreme Nuts 3D, and a hybrid between precision and 3D.

I hope this helped someone out there! Happy Flying!

Friday, November 19, 2010

What Is 3D?

Hey Guys! I thought that I might use what I learned over the course of my flying career to touch on the subject of what 3D really is, and what can help us to be successful at it. I guess the common definition of someone who flies 3D is someone who is completely out of their mind, so that makes me a perfect candidate! I’ve learned that there actually is a scientific definition to the term “3D flying” and that there is a science to it. Now I’m going to use the stuff I’ve learned and try and put it here without confusing you… or myself.

3D is classified as the flying of an RC airplane through extreme maneuvers, mostly high alpha, where the wings are in a complete aerodynamic stall. Although this may be puzzling to a full scale pilot, the realm of RC makes this possible due to the ability to have greater power to weight ratios... and also the fact that nobody will die if the plane crashes... which is very common.
           First thing I would start with is a descent power to weight ratio. A good one to start with is 2:1; for every one pound of airplane you have two pounds of static thrust.

Another thing is to have an airplane that is capable of extreme control throws. This allows the most amount of vectored thrust to be re-directed to make the plane move in a desired direction.

Also, having a propeller with a large diameter is a big help. Without an adequate diameter, 3D is near impossible. I own a Precision Aerobatics Extra 260 48". This airplane has enough vectored thrust for almost every 3D maneuver with a 12x6 prop on a 3S LiPo battery.

A friend of mine owns the same airplane, but was flying with a smaller diameter prop, a 9 or 10 inch, and 3D was impossible. Even though he was flying with a 4S LiPo, which provides more oomph, the plane did not have enough thrust for 3D maneuvers... but man did it sound cool as it was fumbling around looking like a chicken with its head cut off as I attempted to 3D it. The plane could not 3D at all! The small prop made it almost impossible to pull out of a hover, and extremely hard to do a rolling harrier. 

              Having a big prop increases the amount of vectored thrust being blown over the control surfaces. During most 3D maneuvers, the only air flowing over the airplane and its control surfaces is that provided by the propeller. If you have a big prop, then that increases the amount of vectored thrust, and therefore, your control surfaces have more air to move which gives you greater control over your aiplane at different attitudes. If you have a prop that is too small... say bye bye to 3D, because it will be next to if not completely impossible!

            For a beginner, having an airplane with a large amount of wing area will also help with some 3D maneuvers. The maneuver called the harrier benefits from having a larger wing because it disperses the weight of the aircraft over a larger area, therefore making the air lift less weight per square inch. This lifting force is called wing loading.

         Say your airplanes has a 15 oz per square foot wing loading. That means that due to the size of the wing (wing area) and the weight of the plane in ounces, the wing has to lift 15 ounces per square foot of wing.

           Another example of a 3D maneuver is hovering. Obviously, the wings are not producing any lift because the plane is pointed up at 90 degrees. For this maneuver big wings are not needed, and in fact, in some cases it may be better to have smaller wings so that the wind does not influence the aircraft as much. During a hover the only things holding the plane in the air are the power to weight ratio and the control surfaces moving to direct the vectored thrust to keep the nose up at the desired attitude. 

             One more example of a 3D maneuver is the blender. This maneuver can be performed basically anywhere in your flight, and it is a spectacular maneuver. You give full rudder, full aileron in the opposite direction, full down elevator, and full throttle. Having a smaller wing benefits this maneuver as well, as there would be less are resistance during the maneuver. One goal to reach for is to get an airplane with a moderate size wing, such as the 3D Hobby Shop Extra 300 SHP, to learn 3D. Then move on to more advanced airframes.

           Next thing is Center of Gravity. The Center of Gravity, or CG, is the place on the wing where the airplane balances during flight.  For 3D, a slightly aft CG is preferable. There are several reasons for this.

First, is that most of the 3D maneuvers are performed at a “high alpha” attitude, or extreme nose up; so if the nose is up, the tail has to be where? Down! So having more weight back there helps with pilot workload.

Second, having weight in the tail provides the aft end of the plane with more weight, which means more inertia or momentum. This is a good thing. For maneuvers such as an Enema (yes that is its actual name) or a flat spin, you need the extra weight in the tail to provide the momentum needed to swing the tail end around.

Having a tail heavy CG also increases the tail surfaces’ authority. By placing the CG farther aft, the elevator and rudder become more effective because the tail has more leverage since the tail surfaces are now closer to the CG. This is about the opposite of the leverage we are used to; the longer the handle on the wrench, the easier it is to tighten the nut. The reason why the aerodynamics work like this is because the airplane is going to try and rotate around the CG, and now the tail of the airplane has less distance between it and the CG, which means that it can travel less of a distance for the same amount of pitch or yaw; ergo, a quicker response and greater control authority.

Okay... that's enough for today. Happy Flying!

I've attached a video below. It contains many 3D maneuvers.

3DHS Extra 300 SHP Huckin' from Thomas Kitt on Vimeo.

Wednesday, November 17, 2010

Landing a Plane with a hardcore 3D Set-Up

Hey Everyone. Recently I received a comment about landing a plane, like the SHP, when it is set up for extreme 3D. The thing is, Jim is used to flying sport type aircraft, and decided to learn 3D. He is used to making wheel landings with fast airplanes, with a Center of Gravity suitable for pattern and sport flying. He and I share the SHP, which poses a problem: I fly 3D with a very tail heavy set-up, and he flies a little more mild version of 3D (since he is still learning), and pattern style flying. One major thing would be to move the CG forward, but Jim is hell bent on learning to land it with the tail-heavy set-up. Here's my two cents...

First off, don't attempt to make a wheel landing with this airplane, especially at the field we fly at (grass runway); there is a good chance that you will flip it over upon landing. You should try for a 3-point landing. With the current set-up, it is also hard to make a conventional 3-point landing due to the planes tendency to drop the nose when it get's slow enough to pull the nose up to land and not balloon (due to the aft CG). What you need to do is go up and fly and practice the harrier. This way, you can get used to using the throttle to maintain your altitude, airspeed, rate of decent, and attitude. Get proficient with this maneuver and bring it down low (easy with the SHP due to almost zero wing rock) and let the tail of the airplane grab the ground, and decrease the power if needed to let the plane settle down.

With a hardcore 3D machine, there are no pretty landings, just cool lookin' landings. A harrier to landing is a cool looking way to land your aiplane, and is also very practical so you don't have to risk making a high speed landing with a small plane on a grass strip.

Check out the landings on my videos of the SHP. I'm still getting used to the airplane is these videos, so some aren't pretty... but they are practical and very effective.

Hope this helped you out Jim!

Tuesday, November 16, 2010

Trying to figure stuff out...

Hey Guys,

Bare with me as I try to figure some stuff out here... Okay... this "should" be the video of my Extra 300 SHP from

3DHS Extra 300 SHP Huckin' from Thomas Kitt on Vimeo.

3D Hobby Shop Extra 300 SHP

We bought this awesome airframe a few weeks ago and this is how it looked out of the box:

And here is an In Depth video of the individual parts:

And eventually we flew it. Here are those videos:

Please Comment!

First Blog Post

Hey Everybody! There may not be many people reading this since this is my first post, but whatever... if you're reading this, Congradulations! This is my first and definately not last post on my blog. My blog will be centered around RC Airplanes and mainly the 3D and/or Precision Aerobatics portion of the hobby. Let's get the word out and have some fun!