By: Dave Norman
2009 AMA National Champion - 428 Q500

Speed Secrets Volume #1

I thought I would talk a little bit about setting up the center of gravity on your racers. There are a few different schools of thought on this, but I'll just describe what I like in a proper cg. I primarily use the cg to adjust for drift , what I mean by this, is that if you put your plane on knife edge and fly it directly at yourself, does it drift slightly to the canopy or landing gear as its coming towards you? That is what I call drift, and I'll explain one reason why it happens. If your plane is slightly nose heavy, in level flight you have to compensate for that nose heaviness with up elevator trim. This is great when you are flying level, but as soon as you roll to vertical that slight amount of up trim will cause your plane to drift slightly to the canopy. To me, there is nothing worse than making a great turn on #1 where you are lined up perfect coming into #2 and to have your plane start to float in on you. When this happens, you are stuck with pushing the plane out with down elevator, which many racers are not all that comfortable doing. Conversely, if you are slightly tail heavy, you need to compensate for that with down elevator trim. When you roll vertical, your plane will drift away from you. This is frustrating, because you will be giving up the inside track, and flying a longer course. Drift can often be controlled in most cases by simply moving the cg forward or backward; depending on which way the plane is floating on you. I know many people that use the cg to adjust for level flight in knife-edge, but to me, controlling drift is more important than the speed loss due to a couple clicks of rudder. When you consider that you will be negating elevator trim, in trade for rudder trim, it is really a wash anyway. Not that my way is the best, but it seems to work best for me. I absolutely hate adjusting my #1 turn to compensate for a plane that drifts. I like them all to be the same, and eliminating drift is the easiest way for me to make consistent #1 turns.

Earlier, I mentioned pushing a vertical plane away from you when coming in to #2. This is a skill I highly recommend the newer racers work on, and perfect. When I test fly a new racer, I set up the throws per the manufacturer recommendation to get through the first few flights. As I start to dial in the throws to exactly where I like them, I slowly reduce my down elevator throw. I get it so low, that when I'm coming into #2 a little inside, I can simple push full down elevator and the plane will slightly float out without any drastic maneuvers. This can be very handy if you pull a little too hard on pylon #1.

Speed Secrets - Volume 2

Considering all the things a person can do to go fast, what I feel gets missed most often is the attention to details I see on many of the planes on a typical race day. I'm not saying that any one of the little things makes that much of difference by itself, but when looked at a whole, I believe there is a cumulative effect at work.

I will start at the nose of the plane, and work my way back in future articles. Probably the biggest hindrance to speed is the prop on the front of the engine. I will make the assumption that you have the proper size and pitch in place, but what about the prop itself? Is it old, chipped, dry rotted, and showing signs of stress? As APC props age, you will start to see small white stress lines out near the tips, and in my opinion, this is the time to get rid of them. Here is how I like to prepare a prop for racing. First off, I like to ream out the center of the hub from the back with a good tapered reamer. Ream the prop out so that you come close to, but not into the slightly larger ridge molded into the back of the prop. If you go to www.darrolcady.com he sells prop rings for the Nelson engine that you place over the crank that will allow that little recessed ridge to sit perfectly on the spacer sleeve. This will give you a perfectly centered prop on the nose of your engine. At one point there were some prop rings floating about for the O.S. .46, but I am not sure at this point who has access to them. If all else fails, a simple rubber o-ring or two from the hardware store works fine in a pinch.

Next, I have 3 small sanding blocks that I made for preparing my props. They are about 6" long and made with ¾" x ½" pine. I have them set up with 150, 220, and 400 grit papers. If you look at the four edges of a new APC prop, you will see a ridge of plastic flashing that runs all the way around the prop. This flashing is legal to remove, as long as that is all you are removing, you are not allowed to rework the prop, just the flashing. I start with the 150 grit, and make roughly 10-15 passes along one side of the blade to remove the flashing at the TE of the prop, I then go to the LE with 150, and then the same with the other blade. It is important to make the same amount of sanding strokes with your block, or you will throw off the balance. After the 150, I do the same process with the 220, and then again with the 400. You need to be very careful at the tips, as the material gets very thin there. At this point, I take a damp rag and remove the sanding residue. At this point, the flashing should be gone, and you will have a very smooth LE and TE on your prop.

Now that the flashing is removed, it is time to check the balance of the prop. If the reaming, and sanding was done properly, the prop should be very close to balanced. I absolutely hate sanding on one blade for balance, so all I will do at this point, is take a sharpie (green is a good color for this) and mark the heavy blade. This is also a good guide to know that the prop has been properly prepared. When you get ready to install the prop on the engine I will set the piston at top dead center, and place the prop with the heavy blade opposite the engine head. Now that you have what I would call a properly prepared prop, how do you maintain it? After each and every heat on race day, I give the prop a very good look over. Look for chips, dings, and even broken tips from the plywood boards that we launch off of. I like to take a rag or paper towel and clean the prop after each heat as I inspect it for defects.

Speed Secrets - Volume 3

Moving backwards from the prop, lets take a look at that glow plug. Hmmm, I wonder how long that thing has been in there? Well, maybe its time to check. On race day, I like to put a new glow plug in my O.S. and Nelson engines before I test fly at the beginning of a day prior to the 1st heat. This lets you get the needle set perfectly, for that specific glow plug. After the test flight, and after ALL subsequent race heats I like to take the glow plug out and take a look at the element and the color of the base of the plug. There are a lot of signs that can be read from looking at the glow plug. First and foremost in my opinion is the color. There are basically 3 categories that I use to rate the color. The first would be little to no discoloration at all; in other words it still looks basically new. In this case, you are probably running the engine on the rich side, and can lean it out somewhat. The second category would be a very nice "light" shade of brown (or tan). In this case you are very close to the optimum needle setting for the engine. The third category would be a dark brown or black color, which means you are running too lean and you should richen up the engine for the next heat. When I am examining the plug after the heat, I put my glow igniter on it and take a good look as it starts to glow. What I am looking for is any deformity to the shape of the coil, or if it is no longer centered in the plug as it lights . If it's not pretty close to perfect, I will replace it, and put the used plug away and use in my sport planes. My favorite glow plug for our local races is the K&B HP plug; however, they have been tough to find lately. I've been using the McCoy #9's, and the K&B 1L quite a bit also, and they are pretty good. At times I have played with running a short plug, or even doubling up on the glow plug gaskets, but have not come to a definitive conclusion that it has actually helped.

Now that we have the prop and glow plug covered, are you doing anything with that OS or TT Muffler? Historically, these mufflers have been prone to come apart during a heat, which forces you to throttle back, and most often causes a loss of points in that heat (not to mention the cost of a new muffler). There are a lot of ways to prevent this from happening, but I'll share what I have been doing with pretty good success. When I buy a new engine, I immediately take the muffler apart and toss the baffle so I don't forget. I then toss the cheap "Chinese" pot metal rod and nuts in the garbage. I replace the rod with a piece of 6/32-threaded rod; you will need to slightly drill out the ends so that the rod will fit. I clean up the muffler joint with a little acetone, and dry well. I then mix up a small batch of JB Weld. I apply a small amount of JB Weld on the flange that inserts in the back muffler half and slide the two halves together gently and wipe up the spooge that comes out. Insert the threaded rod and attach a nylon lock nut on the front and back. Or, you can double up a couple of 6/32 nuts, which works fine also. At this point, I take the excess JB Weld I mixed and place a blob on the front of the nuts on both the front and back holding everything together and let dry. At this point, you should be in pretty good shape. My only word of caution, is do not tighten the nuts as tight as you can go. Get them slightly tighter than snug, and that will be fine. If you over tighten the nuts, you will put a lot of strain on the threaded rod as it expands less under heat than the aluminum muffler. One last means of safety, if you don't mind the look (and drag), is to take a piece of baling wire, and wrap it around the muffler, holding it in place in case of a breakage. Make sure you check with your local rules before gluing one up tight, some areas require that the muffler can be taken apart to inspect for baffles or modifications inside.

Speed Secrets - Volume #4

Now that we got the prop and engine behind us, I thought I would touch on things that I do with the airframe. I would like to point out, that many people have vastly different ideas in regards to drag reduction. What I try to do, is look at every part of the wing and fuse, and come up with ideas on reducing any excess drag.

This info in regards to sizes is for Q500 424 and 428 classes:

1. Minimum size and weight
a. Keep the firewall at the minimum (2 ¼" square)
b. Keep the fuse width at 2 7/8", preferably near the TE of the wing
c. Keep the fuse height at 3 ½" (this includes the thickness of the wing)
d. Find a way to get to 3 3/4 lbs. A lighter plane will accelerate faster off the ground and as it gets up to speed. It will also accelerate quicker out of a hard turn.

2. Reduce any external protrusions that cause turbulence
a. Mount the switch inside the plane, run a wire or string out to activate the switch
b. For all bolts, use counter sunk heads. This includes all wing hold down, servo hatch, and landing gear bolts
c. Is your antenna flapping in the breeze like a parachute? Check www.darrolcady.com for a great way of keeping your antenna completely internal of your racer. I personally run the antenna forward in a tube, and then back to the tail. Only about 2" of antenna exits just under the tail and I tape this to the side of the plane. Whatever you do here, make sure you are still getting an acceptable range check before flying. The new 2.4 ghz receivers have made this very easy to do inside the fuse.
d. When I travel to a bigger race, I take "speed tape", sold by Darrol and also most Ace hardware stores and cover the wing bolts, the landing gear bolts, the seam at the front and rear of the wing, and also the seams of my servo hatches
e. Clean up the LE and TE of your landing gear. I use a small angled side grinder and do my best to put a symmetrical airfoil on the landing gear. After I get it roughed out I start with 220 grit sandpaper and smooth it out further, then 400 grit, then I use some Mothers metal polish to shine it up nice. If all else fails, you can do it on a belt sander, or even a good ole' file works fine.
f. Use the thin racing wheels availabe at www.darrolcady.com, or www.jettengineering.com
g. Its tough to do with the Arfs, but internal linkages are cleanest, and so are skinned hinges
h. Spend extra time when covering with Monokote or Ultracote. Keep the seams to a minimum and make sure it is applied tightly with no wrinkles or bubbles.
i. I love the look of the vinyl graphics, but all they are is drag. If you want "special effects" or numbers, spend the time to fiberglass and paint. The less seams or protrusions on a wing and fuse the better.
j. Keep the TE of both the wing and tail, as sharp as possible. Using 1/64 ply inset in the edge is very helpful in sharpening this edge. Other materials such as carbon fiber work also
k. After I have mounted my V-Tails to my Seeker kits, I like to use a product called Super-Fil, available from aircraft spruce to make nice little fillets around the v-tail junctions. The Super-Fil sands very nice and is light, but does take a while to dry hard
l. Pot your wing to your fuselage. There are several sources of info regarding this on the net. Potting a wing will help dramatically in keeping proper trim even after removing the wing. It also stops air from getting into the fuse and causing drag
m. I don't like the razor type wing tips (those used on the predator). At some point the covering will wrinkle, and you will not have a smooth surface. The viper tips are much better, and if you can use fiberglass tips they are even better because they are lighter.

That's about all I can think of at this point. It really takes a lot of small changes to make any difference. You won't find any "Quick" ultra speed tricks out there (at least I haven't). Like I mentioned in a previous article, it is a cumulative sorta thing. It takes a lot of small things to gain any sort of speed advantage. It takes a lot of time, and kinda an anal attitude to get there. The benefits of the above changes are quite minimal in our O.S. class, but the gap widens significantly as speeds increase.

Speed Secrets - Volume 5

I'm starting to run out of secrets here, but thought I'd share some of my sources for some of the great products that I use in my Pylon planes. Most of these sources are not local, but in terms of pricing and quality, seem to be the best for me. What I'll do is list my source, and then the products that are available there that I like.

www.darrolcady.com - One of the best one stop shops out there for pylon racing goodies. Here are the products that I like and use from Darrol:

Carbon Fiber Push rods - Best value out there, I like the 1/8" diameter push rods that are a slip fit for a 2/56 rod which can be glued or JB Welded in.

APC Pylon Props - A good place to find all those tough to find props that we use.

Nelson Glow Plugs - He has both Standard and Heavy Duty Plugs.

Engine Measuring Tool - A must have for any serious 428 (Nelson/Jett) racer. Very easy to use.

Torque driver - Another must have for the serious racer.

Pro Driver Glow Igniter - In my opinion the best glow drivers out there.

Prop Rings - Ring to place on crank shaft that allows perfect prop alignment.

Spinner Nuts - Darrol has some very nice spinner nuts in sizes for both the Nelson and the O.S.

Pizza Cutter Wheels - Pretty much the standard on racers today. I prefer Darrol's wheels over others because I think he has a more solid axle design that prevents wobbling of the wheel.

Racer Tape - This stuff is great, I use it to tape antennas down, tape over wing bolts, secure Pole Cat removable engine covers, etc.

Tettra Tanks - The best bubbless tank you can get in my opinion. Available in 4 oz,
5 ¼ oz, and 6 oz sizes.

Super Tanker - Darrol has the full Jett accessory line that includes my favorite bladder tank filler, the Super Tanker. By far the most user friendly of those available.

www.jettengineering.com - This is where you can get the complete line of Dub Jett engines and accessories. The C.G. tank works well in some of the newer mid-wing q40 planes out there, remote needle valves that work on any engine, and a great series written by Dub called the "Crap Trap". Check out the series, there is some great tips and hints in there on going fast.

www.flyfastcomposites.com - Home of the Neme-Q, but one of his products has become the standard in my racing planes, and that is his 720mah NIMH battery. Great battery for our racing application, I'm still not sold on the smaller 500 and 370 mah NIMH batteries, but the 720 has been working fine for me for the past several years. I've been running mostly 4 cell packs, but I also use mostly Futaba gear. For Spektrum/JR 2.4 I believe they recommend either 5 cell or lipo packs.

www.hmracinginc.com - Quite a few neat and unique racing items available. They have a nice flight stand that many of the racers use, the miss candace q40, q40 wing and fuse bags, dolphin mold wax, some neat looking transmitter sticks, etc. Definitely worth taking a look at their products.

www.matneymodels.com - Kevin sells a couple reasonably priced Q500 kits (Mad Dog and Pitbull), a nice racing flight box, and quarter midget 15 kits. I see he also has a new composite quickie available, but I have not seen one, so I would rather not comment.

www.bigbruceracing.com - This is the site of Bruce DeChastle who sells the Polecat and Loki q40 and Shotgun Q500 kit. Both have done well on a national level and are relatively inexpensive compared to their peers.

www.calspeedpro.com - Lyle Larson's California Speed Pros offers the Bird of Prey Q500, Dago Red Q40, Proud Bird, and my favorite the Vendetta. Lyle has a nice offering of competitive planes.

That about does it for sources that I use on a regular basis. If you have any specific question in regards to materials, parts, or accessories that I use, feel free to email me at quickee500@yahoo.com

Speed Secrets #6

The ultimate starter line field box setup for the aspiring pylon racer.

These are the products that I have used the past few years with good success. I don't believe I have ever taken a zero for a no start at any race that I have traveled to and I owe most of that to having a good helper/pusher and good equipment. There is NOTHING more frustrating than to take a zero because of a flooded engine, or low battery in your glow driver or starter. Well, maybe forgetting to push the throttle stick forward at a local race, but that's another story.

I use the Sullivan Deluxe Starter and Power Pack:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFT84&P=7

For a weekend of hard starting 422 and 428 engines, I've found I'm best off with high capacity NIMH batteries for your starter. I can charge before I leave and fly all day Friday, Saturday, and Sunday of a contest without charging until I get home. I use 12 - 3300 mah NIMH cells like these and have been very happy. They are not cheap, but worth the insurance. If you go this route, be very carefull with your initial charges, start at a very low rate (.1 or .2 amps) and cycle several times. Even after using them most of the summer I don't charge at over .5 amps even though the car guys are charging at closer to 3 amps. They have worked very well and will never go back to 1100 mah cells in my starter. The price has really come down on the 3,000 - 3,600 mah batteries so don't skimp on batteries.

For the glow driver, the radio south units are very nice. I use to think they were the best until I tried the RCATS unit at the following link. This glow driver is lithium powered and delivers all the juice you could ask for if you end up with a flooded engine on the line. The Long-Life lithium batteries are also great insurance against something going dead as your trying to get started. I see on the site that they now offer a protective case for this driver. That is a good idea, mine is several years old and has developed a couple of small cracks in the case. Considering I've shipped this thing across the U.S. for several years, I have been very happy with its durability.

http://rcatsystems.com/electronics/ligd.php

As to a tach, there is no comparable tach to the master tach occasionally available used. Keep an eye on the NMPRA website for sale pages in the forum or E-bay.

I do see that the TNC unit is once again available from fromeco. From all accounts, this is a very good tach also.

www.fromeco.org

A third option for an inexpensive accurate tach that I don't see to often, is the Wild Gage offered by Airwild hobbies. I used this tach for some time and it was very serviceable for a $25 tach (currently on clearance):

http://www.airwildhobbies.com/MoreInfo.asp?title=product&id=12

The initial investment is quite high for all of the products listed above, and it took me several years of growing my inventory to what I would consider the best available. There are many other options, but definitely invest in reliable equipment and it will help you avoid zeros for years to come.