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Workshop Build-Along Alien Aircraft ArrowMaster Bipe 5 — Fuselage

Workshop Build-Along Alien Aircraft ArrowMaster Bipe 5 — Fuselage

One of the nice things about building a kit, is that you can make changes to the construction to suit your own tastes. Two areas that I changed on the Alien Aircraft ArrowMaster Bipe, were the mounting of the landing gear and the cabane struts. If you followed the instructions, these are epoxied into place during final assembly of the model. While there’s nothing wrong with this, I wanted to make them removable, in case they got damaged. Being that the cabanes and landing gear both slide into pockets, it was easy to add some plywood on the top and bottom of the mounting plates and add 6-32 blind nuts.

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On the left is the landing gear mounting plate, to the right, is the top of the fuselage. I used scrap ply from the laser-cut sheets and added 6-32 blind nuts. The bolts will be installed from the bottom of the fuselage for the landing gear, and from the top for the cabane struts.

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Here’s the gear plate as it will be installed in the bottom of the fuselage.

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Here’s the fuselage top as it will be installed on the top of the fuselage.

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This is the pocket formed for the landing gear from the layers of ply.

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The landing gear is a 2-piece affair. I used 3, 6-32 bolts on each half to secure them. The same method is used for the cabane struts. Now is a good time to ensure the aluminum parts slide easily into their respective pockets.

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Once the cabanes were fitted, I glued the top of the fuselage in place.

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The top of the fuselage is made from 2 pieces to make a single piece that stretches from the nose all the way to the tail.

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Another view of the cabanes. Note the slots in the top fo the fuselage, formers will be glued into them to give the fuselage its rounded top. The bottom of the fuselage uses the same technique.

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As you can see, all of the parts are interlocking. The laser-cutting of the kit is extremely accurate and makes building the ArrowMaster a joy!

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Here’s a look inside the top of the fuselage. The bulkhead with the 2 holes are for the bottom wing retaining dowels. Now that the basic fuselage is built, mounting the bottom wing is next!

Bottom Wing Setup

Setting up the bottom wing is a pretty simple affair. I did make one change though, instead of tapping the ply wing bolt mount, I epoxied a couple of plywood pads to the inside of the mount and used 1/4-20 blind nuts for the wing bolts.

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The bottom wing is placed in the wing saddle and then centered, I used several rubber bands to tightly hold the wing in place.

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I used a long straight edge ruler and made sure the wing was equal in distance from each wing tip to the rear of the fuselage. Mine measured out to 34-1/16″ on each side.

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Now measure from side to side to center the wing.

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I used a 3/16″ bit to drill the bolt holes. After the first hole was drilled, I used another 3/16″ bit as a locating pin the prevent the wing from moving as I drilled the second hole.

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I made the one inch square pads from 3/16″ ply and drilled the holes for the 1/4-20 blind nuts.

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Here’s the blind nuts for the wing bolts epoxied in place.

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The holes for the wing hold down dowels are now drilled. I secured the wing with the wing bolts and some weight on the front to prevent it from moving. Use the holes in the bulkhead as a guide to drill the 1/4″ holes.

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Now insert the dowels, if the dowels are tight in the holes, use a round file to open the holes as necessary.

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Here’s the dowels in place, I’ll securely epoxy them to the wing after the wing is covered.

Engine Details

The way the nose of the ArrowMaster is designed, lends itself to many engine options. For my build, I decided to use a Saito FG-17 4-stroke gas engine. Being the engine is longer than the recommended OS 2-stroke 65, some changes were needed to accomodate the Saito.The distance from the firewall to the thrust washer on the ArrowMaster is 5 1/2″, and uses an engine box that’s built and installed on the firewall. The gas version of the Saito is rather long because the carb is installed on the rear of the engine, this pushes the engine further forward.

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After taking a few measurements, I determind that I needed to make a plate 3/16″ thick to put the thrust washer of the engine in the proper location. I cut the tabs off of the engine box, and used the engine mount to make the center hole in the parts.

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I used the face of the engine box as it has alignment marks on it making it easy to properly place the engine mount. The 3/16″ ply spacer is glued to the rear of the plate and I used the the engine box to locate the assembly in its correct location. I removed excess material and sanded it flush with the front of the engine plate.

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The engine mount is fastened with 8-32 bolts and blind nuts. The firewall assembly is now ready to the glued into place on the fuselage.

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I used some clamps and 30-minute epoxy the glue the firewall into place.

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Another view of the firewall clamped in place.

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As recommended in the instructions, I added triangle stock to reinforce the firewall joint. The tank floor and bottom of the fuselage will be installed after this area is fuelproofed with a thin coat of epoxy.

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The location of the throttle arm presented an interesting problem on how to run the throttle pushrod. I decided that running the pushrod straight back was the best solution. I used a DuBro flexible cable for the pushrod.

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I drilled a shallow-angle hole for the cable to enter into the radio compartment. I added a spacer to support the cable’s sheath and secured it with ZAP Goop.

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The throttle cable run is friction-free and takes no effort to move it by hand. I can see that I have a couple of options on where to install the throttle servo. I’ll make that decision as I start to install the receiver and other equipment. With this step completed, the rest of the fuselage can now be built.

That’s it for this time, be sure to stay tuned as more updates are to follow.

To see the previous installment of this Build-Along project, click the link: http://www.modelairplanenews.com/blog/2014/08/08/workshop-build-along-alien-aircraft-arrowmaster-4-top-wing/

 

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End loopy takeoffs with a gyro

End loopy takeoffs with a gyro

Like many of you, I have a few different planes, and enjoy flying most of them. However, I do have one or two that are just plain nasty in their ground handling and take offs. You probably have seen these – some Piper Cubs, Beavers, and especially some of the narrow under carriage warbirds. Strangely, not all tail draggers do this. But with one of these “loopy” planes, they are lined up on the runway, power is slowly advanced, and the plane skitters to the left, it skitters to the right, and may loop in a complete circle. Even if it is kept straight for a while, as power is advanced and the tail lifts, it then skewers over to the left from torque. And if insufficient speed has been built up, for example it was heading for the fence and you horsed it up too soon, you are rewarded with a spectacular left wing cartwheel.

I know, when you are relating this story to your mates, you either get a “yup, that’s why I would never get a Beaver, Piper, warbird, whatever …”, or you get a “pilot skill problem, with more flying experience you will be able to handle it.” I understand that more skill may help, but honestly I go flying to have fun, not to work on creating an ulcer worrying whether the plane will get off the ground today. I sure wouldn’t mind some sort of electronic help. And after all, I don’t see people complaining that using exponential on our radios means we are cheating or aren’t skillful flyers.

Now our helicopter brethren long ago found out that even with super human reflexes, it was really difficult to keep the tail straight on their choppers – the least wind, change of engine speed, etc. would make it swing. They discovered gyros. Suddenly, their craft would stay straight, and hovering and flying became a whole lot easier.

The object of a rudder gyro then, is to provide some computer fast electronic help on keeping it straight down the runway on roll out, and fast correction of that torque roll to the left just as it just gets airborne. Once fast enough, the plane generally flies straight without any extra help for sure.

Originally, gyros consisted of a small electric motor spinning two heavy brass disks. These spinning disks resisted movement, just like bicycle wheels or a spinning top. Today, the gyros are solid state and utilize a piezo crystal to detect movement. And specifically, they detect movement only in one rotational direction. Thus a gyro used for rudder control will only detect rotational movement about the yaw axis. Electronics “read” this rotation, and output a correctional signal to the servo, in this case the rudder. Any other movement, i.e. acceleration forward, braking, or pitch and roll are ignored by the gyro.

 There are two kinds of gyros available for model use: rate control (also known as normal mode) and heading hold.

 In Rate Control mode, if anything other than you moving the rudder stick changes the plane’s horizontal direction (yaw), the gyro will give a brief but not sustained correction to help keep it straight.

 In contrast, the heading hold mode is best used just for the take off run. In this mode, when you first line up the plane, you ‘instruct’ the gyro that it is to stay on this exact heading. As you taxi, it will automatically, and lightning fast, make corrections to keep the plane on this heading. After, takeoff, however, unless you want the plane to stay on this course forever, best to switch to normal mode, so that you can turn and do a circuit, etc. Generally on these gyros, you utilize an additional switch on your transmitter to disable the heading hold mode right after takeoff, then defaulting to the rate control mode (normal mode) for the rest of the flight.

 What if we put one of their gyros in our ‘problem’ planes to help with takeoff rudder control? Clearly not all, or even many, of our planes need this, but when you have one of these “ground loopers,” maybe a rudder gyro could help. So, I chose my worst problem planes to try this. The first one is a kit-built electric conversion Mustang, 56” wingspan, about 8 lbs all up battery in. I know, kind of heavy. Never the less, this plane is a lot of fun to fly in the air, and with gear and flaps down, is not so bad to land either. But the take off always makes we wonder if this day is going to end with another trip to the repair bench with it.

 For my first test, I tried a Futaba GY401 heading hold gyro(~$135.00). It mounts next to the receiver with a supplied special double sided foam mounting tape. You plug the one gyro lead into the rudder channel of your receiver, and plug the rudder gyro lead into another lead on the gyro. The third gyro lead plugs into an unused receiver channel to select the gyro mode. I used the Aux 2 switch on my Spektrum DX7 transmitter to switch from ‘heading hold mode’ to ‘normal mode’. The manual describes a few adjustments and selection switch for Futaba digital servo or other analog servo.

After installation and testing, I was off to the flying field. Once I had the plane lined up straight on the runway, I rapidly flipped the Aux switch on and off 3 times, leaving it in the Heading Hold position. This instructs the gyro that this is now the desired course of the plane, and the rudder is in a neutral position. I then accelerated down the runway, and if the course was a bit off, I could still manually move the rudder to keep the plane headed down the middle of the runway. But, virtually all that nasty swing one side to the other was gone, and once some speed is built up, no more torque role to the left! As the plane lifted off, I switched off the heading hold mode, and continued with whatever my usual flight routine would be. Interestingly, in flight, and with the gyro in the Rate Control mode (Normal Mode), I could bank, climb, dive, etc. and the plane really didn’t feel much different to me. Landing was straight forward, perhaps even straighter than usual for me!

 For my next test, I tried the GWS PG-03 gyro ($38) in my electric Spitfire. This plane is 56” wing span, 6 lbs all up. Initially I flew with a 4S-5000 battery, and the plane was reasonable on take off, but still requiring a fair amount of finesse to keep straight and not torque over to the left. However, in the air the plane was a bit underpowered and somewhat anemic in normal flight patterns. Since the motor could h
andle it, I then switched to a 5S-5000 pack, and rebalanced the plane. Now takeoff was not so mild mannered at all, but once in the air a whole lot more power and fun. I installed the GWS gyro by merely taping it to the inside of the fuselage wall close to the receiver, using the supplied special foam mounting tape. The gyro plugs into the rudder channel of the receiver, and the rudder servo lead plugs into the gyro. This gyro is always in Rate Control (normal mode), so no other connections or receiver channels are needed. One simple adjustment, described in the gyro manual, is required to ‘center’ the servo output, and a second adjustment to set maximum sensitivity.

 

Again at the flying field, I now lined up on the runway and slowly accelerated. But this time I still needed to input some torque correcting right rudder transmitter stick movement, but it was much easier. There was no nasty or sudden swinging left to right, and a very smooth takeoff. Once in the air, again, I was not really aware of any impact on my usual flying routine form the gyro. Landing was uneventful, and even easier to keep straight.

 Overall, the heading hold gyro is superior, but more expensive and requires an unused function on your transmitter to turn the modes on and off. The rate control gyro is considerably cheaper, easier to install, and does not require any other transmitter channels. Thus, if I have any more “ground looper” planes, I probably would try the simpler and cheaper rate control (normal mode) gyro first.

 If you try this, and it works nicely as it has for me, then it will be up to you whether you tell any of your fellow pilots about the gyro, or whether you just bask in their complements about how skillful your takeoffs have suddenly become.

By John Falconer

  

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Greased Lightning: 10 electric motors, 10-foot wing!

Greased Lightning: 10 electric motors, 10-foot wing!

Check out this prototype! Engineers at NASA’s Langley Research Center hope unmanned aerial systems like this GL-10 Greased Lightning will be able to fly like a plane and hover like a multirotor. The GL-10 recently flew successfully while tethered; full flight tests are planned in the fall of 2014.

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Soldering Made Easy — Dealing with Printed Circuits

Soldering Made Easy — Dealing with Printed Circuits

Soldering things together takes all forms and sizes relative to our RC hobby. Back in the day, you needed to have the steady hands of an electronic tech guy to assemble entire RC transmitters from kits. Today most of the soldering chores deal with batteries and ESCs. One of the easiest ways to deal with multiple speed controllers, like with quadcopters and other multi-motor models, is to use a power distribution board. These printed circuits are easy to use and require basic soldering skills. Here’s how to do it.

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Here’s a basic power distribution board from HobbyKing. First thing to do is to identify the races for positive and negative polarity. As you see the two races terminate at two points where the battery connection leads will be soldered to.

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The basic tools for the job. The TrakPower soldering station works great and allows adjustment of the soldering iron’s temperature. Also, a holding jig comes in real handy.

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Next you need to strip off some of the insulation from the wire leads and tin the ends. Use sharp good quality tools.

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The easiest way to tin the end of the power leads is to use a holding fixture or jig. Here you see the solder and heat applied to the lead which is sewcurely held in place.

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If the wire leads do not fit the holes in the circuit board, carefully enlarge the holes with a pin-vice and a small drill bit of the proper size.

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Be sure to clean the solder pads on the board before soldering.

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The leads are inserted into the solder points from the back of the board.

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Place the board in a holding fixture, secure the wire lead, and apply a small dab of solder paste.

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Apply heat to one side of the pad and touch the solder to the other side. When the pad and lead are hot enough the solder will flow into the joint.

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Here all of the power leads for the battery pack and the ESCs have been soldered into place on the board. This held simplify the wiring within a model or quadcopter. Be sure to remove any access soldering paste by wiping the board with some rubbing alcohol and a paper towel.

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Everything is now ready to install in a quadcopter or an electric powered B-17 or B-24!

The techniques for soldering are easy and the more you do it, the better you’ll get. Remember use plenty of heat and keep everything clean.

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Keeping Loops Round

Keeping Loops Round

Guard against making the common mistake of releasing too much elevator, aka “hunting,” during the float and thus creating a flat spot on top of the loop. This occurs for the same reason people overcontrol at every skill level: they want to see their inputs doing something. Instead, you should concentrate on smoothly reducing the elevator input to a fixed position that is just enough to keep the loop from pinching. When the float is performed correctly, the loop remains round without any visible sign of when the elevator adjustments where made. When the loop is visible out of round, it’s usually due to trying to manage the float by watching the airplane instead of paying attention to the control inputs.

Since the loop is entered from level flight with more speed compared to the first version of the P loop, propwash and P-factor won’t require corrections until the airplane has entered the slower section of the loop over the top. However, if a strong crosswind exists, you’ll likely need to input your rudder correction earlier and hold it in longer.

After the airplane has made it past the top of the loop, idle the engine to slow the descent and get ready to quickly neutralize the elevator at the instant the plane points straight down. Despite the throttle reduction, airplanes tend to quickly build speed when pointing straight down, so hold the lines before and after the half-roll no longer than a count of “one.” Flying a perfect vertical downline is the mark of a professional-caliber P loop. If you do not have the time to display at least short vertical lines before and after the roll, you’ll have to enter the maneuver higher and/or fly much larger loops to enter the downline higher up. You think of it this way: if you don’t have enough altitude to dive straight at the ground, perform a half roll and pull out, you probably don’t have enough height to perform this version of the P loop. This is what we mean when we talk about “thinking ahead of the airplane!” BY DAVID SCOTT

 

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Half-Scale Bristol Bulldog Takes Flight

Half-Scale Bristol Bulldog Takes Flight

Would you believe this giant model has been flying for over 10 years? Ian Turney-White’s 177-pound, 161-inch-span Bristol Bulldog is powered by a 425cc JPX flat twin. This video was filmed by the father and son team of Dean and Pete Coxon at a Large Model Association aircraft show at the Yorkshire Air Museum in the UK earlier this month. Wow!

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Workshop Tip: Fuel Fitting Rebuild

Workshop Tip: Fuel Fitting Rebuild

The secret to a reliably running engine, is a reliable fuel system, installed and maintained correctly. For either Glow or Gasoline systems, this includes the proper use and up keep of the fueling valves used to fill and empty the tank. Prolonged use, and/or lack of use of your fueling valve can result in the valve leaking and not performing as it should.  Some simple maintenance can help you avoid this and prolong the life of your airplane.

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Even if you clean your airplane every time you fly, after extended use, dirt and debris can get into the valve. This can result in air  and fuel leaks which can lead to lean engine runs.  If you’ve stored your airplane away for a long time,  the O-rings inside the valve can become dry and are easily damaged when the fueling probe in inserted.

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If you do have some of these issues, you don’t have to buy a new Fueling Valve, your best bet is to get a DuBro ”rebuild” kit and replace the wear out components. In only a few minutes you valve will work like new.  If the model has sat unused, it is always a good idea to “lube” the O-rings inside of the valve with a drop of fuel prior to inserting the fueling probe.  This will help avoid the problem of cracking the dry O-rings further extending the life of your valve.

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Large Fueling Valve Rebuild kit.

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Small Fueling Valve Rebuild kit.

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For more information, visit our instructions page on www.dubro.com website at: http://hobby.dubro.com/files/1/instructions

or contact Dubro Products at: 800-848-9411 and speak to the DuBro tech staff.

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Scale Accessories for RC Airplanes

Scale Accessories for RC Airplanes

For our Question of the Week” we’d like to know what turns you on about scale RC airplanes. When it comes to scale model airplanes, its all about the details! Small additions that help bring the model airplane to life. It is easy to improve any model’s appearance by adding scale accessories. For the MAN editors’  perhaps, the most important one, is a scale pilot figure–one with the correct equipment and goggles.

Be sure to check out our exclusive “Scale Accessory Guide” coming in our December “Scale Special Issue” of MAN.

Tell us what your favorite piece of scale detail? Working flaps, scale propeller, dummy engine, retracts? How about a functional bomb drop or a sliding canopy? Instrument panel… machine guns, accurate nose art? Tell us what you like when it comes a top notch scale airplane…

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Dummy rotary and radial engines?

Arizona Model Aircrafters Cockpits

Accurate cockpit and instrument panel details?

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Accurate Airplane Markings and Insignia?

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Scale, period-accurate pilot figure?

 

 

 

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Vaterra 1986 Chevrolet K5 Blazer Ascender Scale Truck

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As soon as Horizon Hobby launched the all-new Vaterra brand (only about a year and a half ago) and the rock crawling community got a look at its Twin Hammers release, there has been a clamor for a traditional scale truck. As overall well received as the Twin Hammers has been, “Yeah, that’s cool, but how about a scale truck?” has been part of the conversation. Well, the wait is over and here it is, the Ascender. We’re sure there will be other Ascender offerings, but the first out of the gate is this 1986 Chevrolet K5 Blazer.

The key points here are the Ascender is the name of the chassis platform and it’s being offered as a kit. The body is clear, so how it looks is up to you. Electronics are also up to you. The item number is VTR03023 and the current price is listed as $320. No official release date has been, well, released as of yet (we’ll keep you posted).

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The Ascender chassis is a ladder frame made out of stamped steel. Stamped steel gives a much more realistic final product compared to chunky machined aluminum, so that’s good. The interesting part is that the chassis is adjustable to allow of four different wheelbase settings: 12.36 in (314mm), 11.9 in (302mm), 11.4 in (290mm) and 10.95 in (278mm).

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So, instead of messing with different links to make the truck longer or short for different bodies, you adjust the chassis. The battery is positioned over the front axle, so the Ascender should have weight distribution optimized in such a way that it lives up to its name and can climb.

The rear suspension is a 4-link setup with aluminum links. The front suspension has a 3-link with panhard bar, which is also technically 4-link setup. The cool part here is the front has a chassis-mounted servo, which is more realistic than a servo mounted to the axle. The shocks feature plastic threaded bodies, so ride height is as easy as twisting a shock collar.

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The transmission features all metal gears and is designed to be fitted with an optional 2-speed setup. The optional 2-speed is a big plus, but even better is that Vaterra includes CV-style front axles with the kit. The Ascender is also equipped with an adjustable slipper clutch. The final drive ratio is listed as 7.86:1.

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The 1986 K-5 Blazer body is fully licensed and features some hard plastic details for the grille. The 1.9 Interco Super Swamper tires are also licensed.

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So, it appears Vaterra may have nailed it. There’s a lot here to like. The adjustable chassis might first seem gimmicky, but the idea of adjusting the wheelbase without having to mess with links is really appealing. The chassis-mounted servo means the Ascender comes stock with one of the most popular modifications. Adding a chassis-mounted servo isn’t all that difficult, but getting the steering and suspension to work properly together if your vehicle is at all modified can require a lot of rather frustrating trial and error. The front CV-style axles are also all sorts of awesome. The body and the stance are spot on. The bottom line is Varerra and the folks at Horizon Hobby made us wait longer than we wanted to, but it appears the Ascender is worth the wait.

Learn more here.

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Pro-Line Car Stand

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Pro-Line has come out with two new car stands inspired by motocross bike stands. Pro-Line’s stands are alloy and come in two sizes, 1/10- and 1/8-scale. They and are laser cut, bent to shape and powder-coated blue. The stands have shock building holes and include rubber grommets to protect your chassis and prevent your car from sliding around.

1/10-scale Stand (part no. 6258-00)
3” tall x 5” x 5.25”
Recommended for 1/10-scale buggies, stadium trucks, short course trucks, 1/10-scale trucks and 1/8=scale buggies

1/8-cale Stand (6257-00)
4.75” tall x 6.5” x 7”
Recommended for 1/8-scale truggies and buggies and monster trucks

Learn more here.