The F-27B Stryker


Barnboy’s ParkZone F-27 “B” Stryker
Guide





Although the F-27B Stryker is a charge-and-fly park flyer,
a few extra steps—and, of course, a little extra
equipment—before trying to toss your bird into the air will go
a long way toward making sure you have the best experience possible.

Barnboy’s ParkZone F-27 “B” Stryker Guide

Although the F-27B Stryker is a charge-and-fly park flyer, a few extra steps—and, of course, a little extra equipment—before trying to toss your bird into the air will go a long way toward making sure you have the best experience possible.

Recommended equipment at a glance:

  • The Stryker and all its hardware in the box

  • One or two spare ParkZone 8-cell Stryker batteries

  • A hobby-quality battery charger, capable of charging two batteries at once. If you have the cash, get one that can charge Lithium Polymer batteries, too (more on this below)

  • A spare propeller or two. Or even three.

  • A digital multimeter

  • Foam-safe CA glue, 3M “Super 77” spray glue, or five-minute epoxy and some clear packing tape for fixing the inevitable “oops”. I usually bring all of these 🙂

1. The Pilot

The Stryker is not a beginner’s plane! It is both fast and unforgiving. You should have at least 5-10 hours of flying time either on a simulator or behind the stick of a trainer-style aircraft before flying the Stryker. If you’ve already bought a Stryker, and are a newbie, go buy another plane that’s actually a trainer… or plan on buying several Strykers (or spending lots of glue and shop time) to replace the ones you wreck trying to learn using this plane.

HobbyZone doesn’t cover crash damage, and once you begin putting the plane together, they are your warranty source, not your local hobby shop. Inspect the parts carefully to make sure they are not broken before assembling.

2. Balancing the plane

  • Ensure your control surfaces are perfectly level with the top of the wing. Laying a ruler on top of the wing and elevon can give you a good idea whether you need to raise or lower the elevon using the clevis.

  • With your lightest battery installed, ensure the center of gravity is at, or slightly ahead of, the two circles in the middle of the handgrip on the bottom of the plane. Nose-heavy planes fly poorly; tail-heavy planes fly once. I just balance on my fingertips.

  • Ensure your plane is balanced laterally, too. Place a finger on the tip of the nose, and one finger under the prop. If the Stryker does not remain perfectly level, add a little weight to the "light" wing, starting near the fuselage and adjusting toward the wingtip until perfect. I use a penny with some strapping tape for this job.

3. The Motor

A "water break-in" of your motor will extend the expected service lifetime, flight time, and power of the stock 480 motor. You should perform this procedure once, before you fly the plane. If you have flown even one time on the motor, this procedure is worthless: the high RPMS, shavings from the brushes, and arcing from powerful amperage has already permanently scarred your motor if used without a break-in.

The idea behind a “water break-in” is to remove the burrs usually found in brushed motors. This prevents arcs and gouges, usually exacerbated by heat, inside the motor. Using one “C” or “D” alkaline cell allows us to do this gently, at low RPMS.

You will need:

  • A standard "C" or "D" battery

  • A wide-mouthed cup of distilled water

  • Some electrical tape

  • A screwdriver

  • 3-in-1 or sewing machine oil

Remove your Stryker motor. I’ve found it’s easiest to just unscrew the mount, leaving the 480 motor in it (it’s glued in there, so is tough to remove). Unplug the leads from the receiver. Immerse the motor, shaft first, into the cup of water up to near the electrical leads. Do not immerse the leads or resistors in the water! Tape the opposite motor leads to the positive and negative terminals of the battery (I find that wrapping the entire battery, top to bottom, in electrical tape helps keep the contacts attached). The motor should begin running at low speed. Let the motor run this way for at least fifteen minutes; running it for longer than an hour, like until the battery is exhausted, may damage the motor (I blew up one motor running it for an entire D battery: bad idea!). Some people like to reverse the leads on the positive and negative terminals to run the motor backwards to further remove particles.

Afterwards, see all the gray chunks floating in the distilled water? That would have been in your motor, gunking up your bushings, shaft, and brushes, while causing electrical arcs. Once you’ve completed the break-in, add just ONE DROP of sewing machine or 3-in-1 oil to the forward and rear bushing (where the shaft attaches to the motor). Do not use more than one drop on each bushing, as if oil gets inside the motor, it may ruin it (or require another water break-in, this time with a little detergent added). You should re-oil these bushings every thirty to fifty flights.

4. The Battery

The ParkZone chargers often under-charge battery packs. You cannot charge an 8-cell or 9-cell HobbyZone battery pack with it. You should buy a hobby-quality charger. I use the "Great Planes Triton DC Computerized Peak Charger". It’s the difference between long, strong runtimes from even your standard packs, and short, underpowered flights where you can barely keep your bird in the air.

You should also invest in a multimeter. They are cheap—around $20-$30—and will help you monitor the health of your battery packs.

If you’re looking to get longer, more powerful run times, the newer “B”-series Strykers can use Lithium Polymer (LiPo) battery packs with just a jumper change! The ParkZone charger, however, cannot charge LiPos, so the aforementioned hobby-quality charger is a prerequisite. Be sure to use the LiPo prop, included with your “B”-series Stryker, with LiPo batteries to avoid invalidating your warranty. A 3-cell (“3S”) 2100mAh narrow-profile LiPo will double or triple your flight time, with much better power and speed.

Important note: if you leave your standard ParkZone charger plugged into your car lighter socket, and remove the key from the ignition, these batteries provide enough power to keep the twelve-volt system in your automobile energized. And that will usually drain your plane’s battery down to nothing very quickly.

5. The First Launch

  • Check your trim tabs to make sure they are centered. You may want to add some “up” trim (slide the elevator trim slider towards you) on launch.

  • Do the range check and motor check as indicated in your manual.

  • Then, run really fast, throw really hard, and throw into the wind, with the nose level or very slightly pointing up.

Following these tips—and the balance tips above—will generally prevent the instant “nose-in” experienced by many first-time Stryker flyers. It won’t prevent you from crashing if you don’t know what you’re doing, though 🙂 The usual problem with nose-in hand launches are due to these factors:

  • The “stock” Stryker’s stall speed is too high for a gentle hand-toss. It needs to be flying fairly quickly at a shallow angle of attack for the prop to bite into the wind. In other words, you can’t possibly throw it harder than it can handle.

  • Although they are a strong, well-balanced combination, the high-RPM motor and small-diameter propeller take several seconds to build up speed. In other words, a solid running start really helps.

  • If thrown at too high an angle of attack (nose pointing up), the prop can’t build up airspeed and power quickly enough to prevent a stall. Attempting to add aileron during a stall will sometimes cause the plane to roll in the opposite direction! In other words, a high-arc toss will probably send your plane plunging into the ground. In sports terms, think “Bullet” or “Fast Ball”, not “Hail Mary”.

  • If there’s any wind at your back when tossing the Stryker, that’s subtracted from its air speed. Even if you have to radically—and maybe temporarily—reposition your flight line, throw it into the wind, always. It’s free airspeed.

It’s helpful to have an experienced flyer evaluate your plane before you fly, and possibly fly it on its maiden voyage. It doesn’t mean your trainer won’t crash your bird—my buddy who flew mine landed it pretty hard—but it raises your chances of making sure your bird stays in one piece. Their insight and tips on your plane’s handling will help, too.

6. The First Landing

If properly balanced, the Stryker will coast into a landing with a moderately nose-high attitude. Land into the wind, keep your wings level, and don’t flare until the last possible moment. If you’re planning on landing on rougher stuff, like the dry lake bed I usually fly from, put some strapping tape on the bottom of the upright fins to absorb the brunt of the scrape.

Don’t stop your motor until the plane is just a few feet from the ground. If done right, the plane will flare and just “pancacke” onto the tarmac (see the ParkZone Stryker video for an example of a perfect landing). If done wrong, you’ll swing nose-high, then plunge into the ground nose-first requiring a repair with that handy glue and strapping tape 🙂

7. Hopping it Up

Many people are fans of improving the Stryker’s performance. I’m not going to go into all the fancy stuff like carbon-fiber wing reinforcements, brushless motors, and those kind of big, non-stock upgrades. That’s the domain of the hobby at large, and your best bet for additional information is to check out the “F-27 Way Past The Limits” threads on the forums at http://www.rcuniverse.com/, in the “Park Flyers” forum. If you want to create a bullet with wings, or an extreme aerobatic flyer with rudders, that’s your best spot for more information.

The most straightforward upgrade is the purchase of Lithium Polymer batteries, mentioned above. These batteries will generally push a “stock” Stryker to about 50 miles per hour, using the HobbyZone-supplied “LiPo Prop” in the F-27B kit. With that speed comes higher roll rates, climb rates, and dive rates. People have found that larger diameter or higher pitch propellers can provide more speed or thrust (not necessarily the same thing!), but the “stock” LiPo prop provides a good balance of speed, power, and motor/battery/electronic speed controller longevity. Deviations from stock equipment may lead to premature ESC (Electronic Speed Controller), motor, or battery failure.

But hey, it’s your plane! It’s your science project. Once you’ve wrecked and fixed your plane once, anyway, your warranty is gone, so what will it hurt, other than maybe your wallet? The Stryker is one of the most easily repairable RTF airframes in existence; the motors and electronics are fairly cheap. Why not have fun with it?

Stop the Vomit, or “keeping your plane in one piece in the air”

Many people report problems with the battery ejecting from the Stryker during inverted flight, particularly during inverted pull-outs. If you slightly widen the battery compartment and epoxy velcro straps into it, you can largely prevent the ejections.

Another problem frequently reported is the battery tearing the electronics apart during ejections due to a crash. If you snip off the “Tamiya Small” plastic connectors on the battery and ESC as provided by HobbyZone, and replace them with “Deans Connectors”, battery ejections are less likely to destroy your electronics.

If you glue a brightly-colored ribbon to your battery, you will improve its visibility in an ejection (a high-speed ejection will often bury your battery in the topsoil!), and make it easier to pull out of the Stryker upon completion of a “normal” flight.

The plastic parts on top of the Stryker frequently part company with the fuselage during high-speed or inverted flight. Epoxying the parts down, however, adds considerable weight and prevents maintenance access to the inside parts. If you plan on a lot of inverted or high-speed work—or, particularly, high-speed inverted work—you should reinforce these with some strapping tape, velcro, or other non-permanent method of holding them onto the plane. The factory-provided pins and battery latch are, unfortunately, a bit of a joke in inverted flight. If the battery is securely fastened using velcro, as mentioned above, the hold-down material for the canopy pieces need not be fastened down extremely tightly.

Control Throws

Be cautious increasing the throw of your elevons. You have a low-rate/high-rate switch on your transmitter: use it! Low rates are useful to prevent stall-inducing hard turns on takeoff and landing, while high rates are great for carving up the sky. Even at the outermost hole of the elevon’s control horn, high rates provide plenty of throw for many sport flyers. If you need faster rates, move the clevis down one position on the control horn at a time until you are comfortable with the low/high-rate behavior.

The “F-27B”, versus the earlier “F-27”, is programmed for much higher roll rates. Be aware of this if upgrading electronics from the original to the “B” version.

Electronics Failure and Upgrades

The addition of Lithium Polymer batteries, combined with high-speed dives and speed or high-rate-induced crashes, will often break, or “strip”, your servos. Crashes will open up the cold solder joints on your electronic speed controller/receiver unit. You may overheat your ESC. Regardless, at some point, the electronic gear in your Stryker will probably fail, resulting in a crash, more repairs, and replacement parts.

Unfortunately, you can only use ParkZone-branded electronics to replace the stock ones, unless you want to change ALL your electronics: transmitter, receiver, servos, and electronic speed controller. Many people consider this option the most attractive, as it opens up more avenues for future upgrades: brushless motors, additional channels for rudders, airbrakes, lost plane locators, etc. The possibilities are limitless.

Regardless, if you drive your Stryker hard, and a lot, you will probably reach a point where you begin considering replacing the stock ParkZone gear with higher-grade stuff. This guide can’t cover all the possibilities, except to say that, if you just replace your ParkZone electronics with more ParkZone electronics, you’ll probably end up on a never-ending nickel-and-dime treadmill of ordering replacement parts at your local hobby shop 🙂 It may be wise to fly conservatively on the stock ParkZone gear, with an eye towards saving for higher-performance gear in the future.

Or just thrash the heck out of it, planning for your next plane 🙂 Once again: your plane, your science project.

If you plan to upgrade to standard electronics, be sure to go for “micro”-sized parts. Your Stryker is weight-sensitive, and although the high speeds you can reach using brushless motors may allow for more weight, this also means faster belly-scraper landings.

Good luck. You’ve chosen a fun airframe that lets you do a lot with it. Enjoy yourself, and stock up on your foam-safe glues!

Feedback always welcome,

Matthew “Barnboy” Barnson

matthew@barnson.org