EF-1 Set up & Theory
The Wine Country Flyers club has just had its first pylon race of the season. With it brings a new class called EF-1. I thought it might be a good idea to write this article as a primer to EF-1, and maybe encourage some new folks to give it a shot, or at least come out and watch.
Electric Formula One, or EF-1 as it has become known, is a new pylon racing class designed to be flown on a national (& international!) level. It is being spearheaded within the NMPRA (National Miniature Pylon Racing Association) by Jerry Small and Danny Kane. There are the guys who came up with the idea and also serve on the aircraft and equipment approval board. The class is being flown in conjunction with regular nitro Q-40 & Q-500 races as well as on their own. It was flown at the NATS this year and had over 60 entries! The class came about with two things in mind; 1) entice some new folks to try racing, and bring back some old ones who had quit 2) & to recapture some of the fun of the screaming nitro formula one days and their scale appearance.
While EF-1 is no scale contest, the aircraft do need to be based on a real Formula One racer, so they all look pretty cool. There are a couple of ARF’s available now, (Pogo & Shoestring from E-Flight) as well as a few kits, with more on the way. They all must conform to a pretty strict set of rules designed in such a way that the pilot is the most important part of the equation, and everyone will have access to the same equipment, so no buying wins here! The rules can be found here: http://www.nmpra.org/rules/EF1NewRules_5_%5B1%5D.pdf
With all aircraft & motors being essentially equal, aircraft set-up becomes paramount. Here are a few tips to get your aircraft ready to race. No matter if you have an ARF or are building a kit, attention to detail will mean the difference between a reliable, easy to fly plane, and one that will make you not ever trust it. Racing is as much about pilot confidence as it is anything else. These planes are no different; you have to feel like the plane is solid, so that you can concentrate on holding your line, passing or staying out of trouble.
I’ll assume that you have the plane together at this point. It must be built straight, true and warp free. Most warps can be corrected with a hot iron and heat gun. Getting a buddy to help twist and heat will make this task much easier. It’s a good idea to check the incidence as well. It should be 0-0-0 with maybe 1-2 degrees at most right thrust. I don’t use any. Check the C.G. This is a critical measurement, don’t try to second guess what the manufacturer suggests. Put it where they tell you to and fly first. Once you have a flight or two on it, then you can play with it, not before. I’ll touch more on how to set C.G. bit later.
You want to use as much of the servo travel as possible. This usually means using the inner most hole on the servo, and the outer most hole on the control horn. It is much better to do it this way instead of cutting down your throw in the radio as it preserves your servo resolution and makes for smooth controls.
Make sure you set up dual rates and expo. For me, I like to have a pretty soft airplane on low or racing rates. I look for enough throw to make a turn with about ¾ or the total deflection, with the rest for emergencies. Don’t make the mistake of using a lot of control thinking your plane will be more “agile” or faster through he turns, this is simply not the case. Over controlling is bad! I run 30-40% expo to start and fine tune to taste. Remove most of the down elevator travel, you don’t need very much, only enough to make the turn at full deflection plus a little bit more for emergencies. About a 100’ loop at full throttle is what you want. I set my plane to fly level at full throttle, or maybe dive slightly. This can come in handy if you over pull a corner and are headed towards the middle of the course. You can simply neutralize the elevator and it will drift back out while still in knife edge. About 30% differential is also a good place to start for axial rolls.
I like to run spoilers for landing. Contrary to popular belief, these planes actually fly pretty well slow if they are set up correctly, so don’t be afraid. I deflect both ailerons up about the same amount as a full deflection roll input on low rate, so each aileron is up maybe ¼” or so. Then I set them so that when I give full aileron input, the up side aileron only moves up a little and the down side goes down no more than level with the wing. You will also likely need some down elevator mixed in to eliminate any pitch change when they are applied. When they are set up this way, the plane becomes simple to bleed off speed and land. With the down side aileron never going below neutral, tip stalls are all but eliminated because of the aerodynamic washout, & has the added bonus of self-coordinating turns at the lower airspeed due to the added differential. Win win!
Now we will set the C.G. First, mark your plane so the battery goes in the same spot every time. Take it up and get it trimmed out. I set my plane to fly level at full throttle, or maybe dive slightly. This can come in handy if you over pull a corner and are headed towards the middle of the course. You can simply neutralize the elevator and it will drift back out while still in knife edge. Roll inverted, it should continue on relatively level for a few seconds then begin to descend slightly, only requiring slight pressure to maintain altitude. If it dives for the ground rapidly, you are likely nose heavy, which will be evidenced by the up elevator trim once you land. If you move the battery, be sure to mark its new location.
Once you have a few packs through your plane, it’s time to get down on the course and run some laps. Your plane should be able to roll to knife edge, pull through the corner, roll out and head down the straight with little effort and change in altitude. Often a new racer will dig (roll into) or dish (roll out of) a turn. This can be quite disconcerting! The dig is easy to deal with. It is usually caused by the lateral balance being off. A little bit of weight in the right wing tip will do the trick. My Nemesis used to dig; now it has ¼ oz. in the right wing and flies true. A tiny bit of right rudder trim may help too. Dishing is usually caused by too much elevator throw coupled with a forward C.G. The answer here obviously is to reduce elevator throw and move the C.G. to the proper spot. Play with your elevator and aileron rates and expo until you can take the turns smoothly and without feeling rushed. Smoothness counts here, jumpy inputs means you are flying a longer course and the extra deflection is slowing you down.
So now your plane is dialed in and smooth and you are comfortable flying laps. What next? Well, there are a few things that will make sure you are getting the most speed out of your setup. Let’s start are the front of the plane and work our way back.
It goes without saying that your prop must be balanced including the hub. But what about the spinner? It is a leading source of power robbing vibration as well. If you’re not sure how to balance these, take a look at this: http://www.youtube.com/watch?v=1JuSujZ_pFw Be sure to watch all three parts! Next take a look at your ESC. If it has adjustable timing, play with all of the settings and see which one gives you the most rpm. If you have one of Castle’s ICE controllers, it will record in flight RPM for the most accurate numbers. Moving on to the battery, you will want the highest capacity and highest C rating you can get that still is under the 325 gram max weight limit. Looking at the outside of the plane, clean and smooth is what we are looking for. Use tape or covering material to seal up the control surface gaps & other seams or exposed surfaces. Drag reduction will go a long way here. Clean up any wrinkled or loose covering while you are at it. Now it’s just practice, practice, and more practice!
That’s it! You and your plane are now ready to race and have a great chance at placing well. If you are not sure if EF-1 is for you, come to a race and check it out!
See you at the field