Magnum Tazer 800 Build

[cbergen]

There is plenty of room on the battery tray for most any requirements, you can also use the bottom of the tray...For this application, without the vibes of a gas engine when I usually install a strong box for the Rx and such, I just laid down some sticky backed Velcro and stick the Rx to it.

A wrap around gives me some more piece of mind, but when you want to move the Rx, you'll find it pretty darn difficult to get it loose from the Velcro bed...

We have in stock (a LOT of stock, ooops) packages of different colored tye wraps from FMP. Use them or Velcro one wraps to secure your wiring into a nice neat bundle. Prevents chafing and loose connections, and looks a whole lot better than a rat's nest.....

[cbergen]

With the front end completed, we move to the tail.

The tail boom is aluminum, the Torque Tube drive is aluminum, the boom supports are aluminum, the tail pushrod is......carbon fiber.......HA!

The fins are G10, the tail gearbox is an open style (seems to be a popular way these days...) and aluminum with substantial nylon gears and a 6mm input and output shaft.

For the Tazer 800 and it's extended boom to allow 800mm blades, we use 2 TT shafts and a coupler/bearing carrier with 2 bearings to support it.

[cbergen]

With the whole assy together, we highly suggest that you "pin" or secure the shafts to the connections. Do this by drilling through the aluminum shaft with a #50 drill bit and creating a divot in whatever is inside the aluminum shaft (gearbox input shaft, coupler in the middle, or dogbone in the front)

The setscrew in that particular hole will then seat down in the divot securing the aluminum shaft, preventing it from rotating on whatever is inside at that particular point.

It is only necessary to do this for ONE setscrew at each joint, NOT all 3. By drilling all three, you run the risk of cracking the end of the aluminum shaft, which then defeats the purpose of securing it.....

Complete assy, ready to install into the tail boom.

[cbergen]

To install the tail drivetrain into the boom, coat the bearing carrier with some grease. This will also make removal, if needed, a lot easier as well. Note that this is ONLY for the longer boom with 2 TT shafts. we'll cover the standard boom later.

Push it all the way in and align the holes for the gearbox screws. If they're not quite lined up, rotate the gearbox inside the boom 180 degrees.

Install the 2 3X4 SHCS bolts. These bolts have been a concern to some. They do NOT require a lot of torque on them, only blue loctite and a snug tightening. If there are vibrations in the tail (tail blades out of balance, a bent hub, for instance) then it is possile that these bolts can come free, just like any other bolt on a helicopter that is vibrating.

Before installing the boom into the helicopter, don't forget the horizontal fin clamp....

[cbergen]

Install the boom into the boom clamps, pushing it ALL the way to engage the dog bone into the delrin coupler.

Now pull it back out 1mm, just enough to relieve any rearward pressure on the tail drivetrain without disengaging the dog bone from the coupler.

After leveling the gearbox, tighten the boom clamps, securing the boom to the heli. There is no need to wrap the boom with electrical tape, or install sandpaper, the clamps will DEFINITELY hold this boom in place!!

[cbergen]

Our boom supports are aluminum, with delrin threaded inserts on the ends.

The supports are also threaded on the inside, use JB weld to secure the ends into the supports.

Attach them to the bottom of the lower frames, on the outside for maximum boom support, and to the horizontal fin clamp. Install the horizontal fin BEFORE tightening the clamp bolt.

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Install the vertical fin, using the remainder of the boom clamps.

Ensure the fins are straight, the vertical fin is vertical, the horizontal fin is horizontal.

(you'd be amazed by how many people don't know what this means.... )

[cbergen]

The tail bellcrank is the improved one from a couple years ago. It uses 2 bearings and a spacer between the bearings for a free moving tail control system.

On this gearbox it gets a medium ball, then the bolt is threaded into the pitch arm, setting the tension on the bearings for freedom of movement and no slop, then is secured with a jamnut.

If an adjustment is needed, loosen the jamnut first, adjust the bolt, then tighten the jamnut again.

[cbergen]

The pitch slider is dual ball bearinged, the pitch plate is threaded onto the tube with a left hand thread, which keeps it secured without any JB weld. By the way, all assemblies that you find in our kit such as the pitch slider and tail gearbox are permanent assemblies, meaning it is NOT necessary for you to take them apart, loctite, and reassemble.

The fit to the shaft and the materials are such that it does require lubrication. Use a light machine oil such as 3 in 1 to ensure a free moving system. The shaft itself may require cleaning from deposits left when it was ground. A little 409 takes care of it.

The medium ball sits in the delrin cup of the bellcrank. If this joint is a little tight, use your ball link reaming tool to size the cup. It is possible to replace the cup if needed, it's threaded into the bellcrank.

[cbergen]

The tail rotor system consists of a HD steel hub (standard, not an upgrade or aftermarket piece), aluminum tail blade grips (standard, not an upgrade or aftermarket piece) with 2 radial bearings already installed and a thrust bearing.

These are the new improved geometry grips, enhancing the tail control system.

The hub is installed onto the shaft with ONE setscrew, and loctite of course, with the setscrew seating into the divot on the 6 mm output shaft.

[cbergen]

The linkage between the pitch slider and tail blade grips are these shoulder bolts, eyelets and plastic links.

Some care here will make a tremendous difference in how your tail "feels" and how well your servo and gyro combo work.

The shoulder bolt is a precise fit into the eyelet, so some lubrication here is needed. Loctite is NOT a lubricant, so take great care to NOT get it into the joint when installing this assy onto the tail blade grip.

When I lubricate my tail output shaft daily, I also lubricate this joint with a drop of 3 in 1 oil.

[cbergen]

The layout for the thrust bearings and installation of the tail blade grips.

Notice the shim/washer that goes in first, then the thrust washer that has the larger inner diameter, the ball cage, the thrust washer with the smaller inner diameter, and the securing bolt with washer.

Grease the ball cage before installation, and bolt everything up.

The bolts we use are a high grade bolt, and have only had one pop off due to EXTREME torque being applied to them (and this was some time ago....) We use this exact same system on our Industrial birds swinging 130mm tail blades without any reports of any problems. Your 95mm or 110 mm tail blades should be no problem!!!

[cbergen]

Once installed, you will find some in and out play. This is normal and necessary. When the system is spun up to the appx 8,000 RPM normal operating range, the grips will be slung outward with ALL pressure being against the thrust bearings WHERE IT BELONGS.

Do not shim the play out. Doing so may cause some unintended consequences such as failing bolts, breaking output shafts, vibrations, etc, etc.

[cbergen]

The special ball links we use for tail pitch control require trimming and setup.

First off, remove the ribs on the sides. In extremes of travel they MAY contact the tail blade grips causing a small amount of binding.

Cut the length of the link to 17mm.

Then thread them onto the eyelet.

Snap the link onto the pitch slider balls, noting the orientation, giving a leading edge control.

With the pitch slider centered on the output shaft, the horn on the blade grips should be pointed straight up and down. This is the improved geometry. When hovering, centrifugal force will be pulling on these horns straight out while keeping the proper angle on the tail blades for holding the tail still, relieving the workload from your very low torque tail servo.

It also gives a consistent feel to yaw commands both left and right.

[cbergen]

The tail blades included are plastic, 95mm long. You can run up to a 110mm long blade for increased tail authority. They install the same way.

Place a shim/washer on either side of the blade and slide the whole affair into the blade grip, lining up the hole. Install the shouldered bolt (shouldered for strength, vs an all threaded bolt) and nut on the opposite side.

There are 2 schools of thought on how tight to make the blades. I tighten mine up enough that they won't fall under their own weight, but can still be moved by hand very easily. Others leave them very loose, depending on centrifugal force to pull them out. I am not aware of any problems either way.

Note the direction of rotation and the "leading edge control".

Also note the tail fin on the OPPOSITE side from the tail rotor....

[cbergen]

The tail pushrod is Carbon Fiber, for a variety of reasons, it's stiff down the length (doesn't bend easily, therefore doesn't require much support), it's lightweight, and readily available.

Carbon rods CAN split lengthwise, so we utilize an aluminum end on the OUTSIDE of the rod, preventing splits from starting at the ends.

Install the SHCS bolt from the inside of the cap, run the nut down and install the ball link, repeat for other end.

[cbergen]

Using JB weld, install one end onto the pushrod.

Snap this end onto the tail servo ball and with power appllied (gyro switch in non HH to center the servo), Hold it up to the other end where you have installed the rear cap onto the ball on the tail pitch bellcrank.

Mark where it needs to be cut, alowing room for the head of the bolt inside the cap, cut the rod and JB weld the cap onto it.

The ball links allow for fine tuning of the length of the tail control rod, but only to center the pitch slider onto the tail output shaft.

[cbergen]

Mounting the fibreglass canopy is the final step on assy of the heli. We suggest doing the actual cutting AFTER the canopy has been painted. The ears can be a bit flimsy after cutting the center out, which makes sanding the canopy a little difficult. If one is careful, it's not too much trouble, and it is suggested to seal the edges of the paint with CA after cutting. The cutout area is marked very lightly in the fibreglass, although the sanding and painting of the canopy may erase it. Make yourself a paper template prior to painting.

The initial holes are made with an 1/8th" drill bit, then the canopy is placed on the heli to verify that everything lines up. An adjustment can be made at this point by relocating the 1/8th" hole where necessary.

When you have them lined up, use a 5/16th drill bit, RUNNING BACKWARDS, to open up the hole for the rubber gromets. By running backwards the drill bit won't grab and tear the fibreglass or paint.

Install the rubber grommets, putting a drop of CA on the INSIDE to secure them and add to their lifetime.

[cbergen]

This is everything included in your kit. We'll work on setups, blade installations, battery installations and speed control setups next.

We will have this bird at the Birmingham Funfly, and will be giving away a Magnum Tazer kit to some lucky registered pilot! So come join us for a great time at Dave Harkey's place. I'll let you fly this bird (if you can demonstrate that you can at least hover ), and show off all of the current offerings from Bergen R/C.

[cbergen]

The Tazer 800 is now available, http://bergenrc.com/SearchResults.ph...042&Submit2=Go