Twisted Hobbys - Crack Turbo BEaver

[Hercdriver7777]

CRACK TURBO BEAVER

Introducing the Crack Turbo Beaver!

The Crack Turbo Beaver represents the ultimate in RC fun! Equally at home in bush style flying and extreme 3D, the Crack Turbo Beaver is also surprisingly precise and offers unparalleled durability. The huge EPP tires easily roll over gravel, dirt, rocks, tall grass, and other airplanes. The unique X-shaped fuselage design adds scale looks in the air as well as high stiffness with no need for additional carbon bracing, while the rolled cowl and canopy add to the scale outline and lend tremendous strength to the front of the aircraft.

Designed and developed by Twisted Hobbys team members Chris Jewett and Cody Wojcik, the Crack Turbo Beaver takes the extreme design philosophy that produced the renowned Crack Yak, Crack Pitts, and Crack Laser and gives the Crack treatment to the famous DeHavilland Turbo Beaver bush plane. RCFactory adds their world-class manufacturing techniques and the highest quality EPP foam available. The result is just about as much fun as you can have with an RC airplane! Harriers, hovers, precise knife-edge, rolling harriers, flat spins, snap rolls, and other high-performance aerobatics compliment the traditional loops and barrel rolls you would expect from a high-wing plane. The high wing placement means that the Crack Turbo Beaver is also very stable, and makes a great beginner's aircraft, or just lazily cruising around the back yard. Of course, being nearly indestructible means you can fly between trees, spot-land on your picnic table, and try other crazy things that you'd never do with a balsa airplane.

Equipped with four 5-gram servos, a 2S 350-3S 650 battery, and 19-26 gram motor, the Crack Turbo Beaver is exceptionally versatile and will fly well on a wide variety of equipment and CG placements. Of course, Twisted Hobbys keeps everything simple as always with a proven plug-and-play power combo that provides great performance at a reasonable price.

Pair your Crack Turbo Beaver with any computerized 5+ channel radio and enable flaperons and spoilerons for even more fun and capability! Near-vertical stalled descents with the spoilers up, low-speed scale flying with the flaps down, and super-tight loops with the flaps mixed to the elevator add even more depth to the CTB's repertoire.

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Videos:

Here is a video from our guys at the factory in the Czech Republic enjoying their Beaver prototype:

http://youtu.be/gm3xbKVkNcE

Here's a vid of today's first flights with the production model. Man does it look great!

http://www.youtube.com/watch?v=ro-Pxsa_kDY&feature=youtu.be

Build Video:

http://youtu.be/HaeX-9MK0xc

Beaver 101:

http://youtu.be/Mji7p3MddNc
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[Hercdriver7777]

Build Log​

Tools Required:

-Exacto Knife with Sharp Blades
-Welder's Adhesive
-Small Phillips Screw Driver
-Small Flat Tip Screw Driver
-Paper Towels
-5/64" Drill Bit
-Medium or Thick CA
-Thin CA
-CA Accelerator
-Thread (Carbon, Kevlar or Cotton)
-Heat gun/Torch/Lighter (Something to shrink heat shrink tubing)
-Medium to Light Sandpaper
-Wax Paper or Wide Clear Packing Tape
-Blenderm Tape (Optional)
-Hot Glue (Optional)
-Rubber Gloves (Optional)

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Get the wing and tail feather out of the box, fully deflect the control surfaces by folding them under and put a weight on them for about 10 minutes to loosen the hinges. Remove the rest of the parts from the box and prepare your building surface in that time.

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Take both wing halves and use a sharp blade to remove the little pieces of foam that remain in the slots and tabs after production.

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Prepare the wing halves to be glued together. Put a light coat of Welder's on each half of the center wing joint and let it tack up for a few minutes before joining the halves. The tabs in this joint will prevent you from assembling this joint incorrectly provided that you don't force the bigger alignment nub into the smaller alignment nub's spot.

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Once you have the joint put together and the glue is kind of holding it together, put it on a flat surface with some weights to hold it together and let it dry for 10 minutes.

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Prepare to glue in the wing spar by putting Welder's in the wing spar slot and on the wing spar itself. Don't be shy with the glue here and make sure to work fast so you can put the spar in while the glue is still wet. You will be able to clean up any excess glue with a paper towel after you get the spar in. Once the spar is in make sure to go back with the glue and fill in any spots where you did not get enough in.

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After you are satisfied with the glue and spar situation you need to weight the wing down flat and straight. I use a wide piece of clear tape on the bench just under the spar to keep the wing from sticking to the bench. You could also use wax paper.

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An optional step that both Cody and I recommend is to put a little Blenderm tape at the inner and outer hinge joints on all the hinges. This will make the plane vastly more durable that it already is, which is amazing, and its easy. Just cut a little piece of tape, put Welder's across the hinge line where you want the tape, put the tape down, go around the edges with Welder's and then wipe up excess.

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Locate the two fuselage pieces and gear leg pieces and glue the gear legs onto the fuse halves using Welder's. Again, the assembly tabs here will keep you from messing this up.

WARNING - Stop after gluing the foam pieces together. Read the next step before gluing in the carbon pieces.

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WARNING - Follow this step closely.

You now have two fuselage halves. One of them needs to be cut in two lengthwise and has little markers cut into the tabs that show you where to cut. This is not a critical cut as it will be glued back together however you cut it and buried in the center of the fuselage joint but you need to not glue the carbon stiffeners for the gear into the top part of the fuselage that you are separating.

Locate the 4 flat carbon stiffeners in the kit, the shortest two are the front gear legs and the longest ones are the rear legs. There are lasered slots in the fuse that these rods go into. Fill those slots with Welder's and then put the stiffeners in and wipe up the excess.

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While the glue is drying on the gear legs you can start to assemble the wheels. First remove the plywood hubs from their sheet and then glue the three wheel halves together with the solid piece of foam in the center. Put some weight on them and let dry for about 30 min. It's good to work ahead when building with Welder's

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Another thing we can do to work ahead while things dry is to remove the rest of the foam parts from their sheets as well.

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Now that the gear legs have had some time to dry it is time to put together the fuselage. The first step is to attach the bottom half of the fuselage to the other side of the fuselage. Trial fit this a couple of times before you start gluing. It goes together easily but this part of the build is a bit different than most planes because of the X shape of the fuselage it can be disorienting.

You need to make sure that the fuselage pieces dry 90 degrees to each other. I couldn't find my square but you get the idea.

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While the fuselage dries we can work ahead by installing the hubs in the tires.

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[Hercdriver7777]

Working ahead again, glue in the plywood gear leg tips. If you use Welder's for this it will make a very durable joint but it needs to be absolutely dry before you finish the last steps in the build. So, if you are in a hurry you can use CA for this step, which will be less durable but faster.

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Same story with installing the axles. We use Welder's and let it dry completely before wrapping with thread in the final steps of the build. You could use CA to speed this up. Whichever method you use, install the axle so that enough is sticking out of the back of the plywood piece that you will have something to grab on to with thread when we wrap it later.

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We are now at a point where we can install the wing. There will be some debate about whether to install the wing now at this step or to completely install the radio gear first and install the wing after. The plus to waiting and doing it later is that it is easier to install the servos and pushrod guides without the wing attached. I like to do as much building as I can and save the radio install until the last step. Either way is fine. You choose.

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While the wing joint is drying we can get the motor mount ready to glue. Put Welder's on the X mount and on the front of the fuselage and let tack up for 5 minutes or so.

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It is time to start installing control horns. Remove them from the thin plywood sheet.

There are 4 control horns. The two smaller ones are for the tail and the shortest of those is for the elevator.

There are lasered marks for where the control horns go. On the ailerons you will want to use your sharp knife to cut a slit all the way through the aileron along that laser mark. Fill that slot with Welder's and install the aileron horns all the way through the foam and flush with the top surface of the aileron. Clean up excess glue.

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By the time you get done with the aileron horns the X mount should be dry enough to install. Again here we like to use the Blenderm and Welders reinforcement method to make the motor mount bulletproof. Cut four pieces and reinforce all for parts of the X mount. Highly recommended.

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Continue gluing in control horns

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We use the Blenderm reinforcement on all the hinge lines. Remember you just need a little piece at both the extremes of the hinge line.

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Now we are going to finish and install the elevator. First attach the two fins to the counter balances of the elevator with Welder's. Then put glue into the elevator shelf area and glue on the stab. Use the tab slots and the centerline of the X fuse to line it up straight.

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To install the fin and rudder you need to apply Welder's to the bottom of the fin where it attaches to the horizontal stab but also to the long front part of the fin where it glues to the fuselage. On the long front part you only need glue on the outside edges of the piece because it does not sit flush in the X of the fuse. After the upper half of the rudder and fin have dried you can install the bottom part of the fin. I use a dry method install here (let the Welder's tack up for 5 min) because the part where the fin meets up with the rudder and hinge line can fight you if you don't have a quick bond. Make sure it is straight and vertical.

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[Hercdriver7777]

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Get your radio gear ready. Install the long single sided servo arms that come in the servo kits. Center your arms and make sure they are all put on the servo in the correct direction (reference pics).

The aileron servo is output gear forward and arms down.

The tail servos are output gear to the rear and arms to the center.

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For the aileron servo you need to cut a little channel for the wires to pass through into the fuselage if you glued the wing on already. If not then just bury the wires in the slot lasered into the wing that lead to the center. To glue in the servos just put a little welders in the servo mounting tab area and another on the bottom of the servo. No need for a lot of glue and if you ever need to change out a servo you will be happy that you didn't go overboard. The aileron servo should be put in flush with the top of the wing.

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Make your pushrods. This kit requires one Z bend to be attached to each pushrod. The other end will go to an adjustable link. Start by roughing up the ends of each rod and the Z bends. Then cut your heatshrink into 4 pieces. Hang one of the heatshrink pieces on the end of the rod and insert the Z bend. Fill the heatshrink with thin CA and then shrink the tubing. This will squeeze out the excess CA. Careful if you use a torch because CA is flamable.

Install the quick link into the servo arm on the ailerons and into the control horns for the tail.

Cut off excess rod.

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The tail servos have the Z bend in the servo side and you can insert the pushrod through the servo hole. The tail servos are installed flush with the outside of the fuse.

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To finish the tail pushrods you need to install the pushrod guides onto the pushrods. There are 6 for the rudder side (left) and 5 for the elevator side (right). Slide them all onto the rod and trial fit them to get the most straight and direct rout from the servo to the control horn. You can angle them or move them in and out of the lasered holes to make this work. Once you are happy with alignment use thick or medium CA to glue in the guides. Then install the quick links on the control horns, cut to length and tighten with the control surfaces centered.

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[Hercdriver7777]

Install the motor with wires on the bottom. Then install the Canard/turbine exits and the SFGs.

This is called an Antennalizer. It does actually do something.

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Finishing the axle. Once your plywood and axle are completely dry you can wrap them with thread and hit them with thin CA. Some people don't like the way this looks and prefer just to use more Welder's to reinforce the area. That will work OK but if you wrap it well with thread making sure to go over, under, around and sideways and use a quality CA the joint is tough as nails.

Insert one of the axle nuts on before the wheel.

Make sure the glue is completely dry and clean out the axle hole with a 5/64" drill.

Install the outside nut and put a small bit of welders on the outside of the nut to hold it in place. Keep in mind that you may want to remove the wheels in the future for floats.

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The CG for this airplane is 1/2" behind the spar. This plane runs on either the 3S or 2S setup and the battery pretty ends up a little in front of the CG mark but this plane is very insensitive to CG. So, you should be able to switch back and forth without affecting CG.

Even though I am holding the plane upside down here checking the CG the CG is measured .5 inches from the back of the wing spar.

Once you have determined battery location you can make a battery slot. You can use velcro on this bird if you like but we like the slot method because it gets the center of the weight closer to the roll axis. Just remember to make the slot a little smaller than the battery. If you put some welders around the hole it makes a nice grippy surface after the glue has dried.

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After the battery slot is good to go you need to cut one small slit for the ESC lead to the RX to go through the X of the fuselage and into the Canopy area.

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Once the radio setup is complete you can install the Canopy with Welder's using the dry method. You can still get to the RX with the Canopy in place but it not as easy.

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I use hot glue to hold my ESC in place. You can also glue down the wires from the ESC (make sure you can still get the bullet connectors out) and also put some glue on the wires coming out of the motor. We have found that where the wires come out of the motor they can break over time and with the rough use that we put on these things. The glue will keep the wires from moving much and prolong their life.

Make sure the motor is turning the right way.

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It's finished! Go fly it!

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[Hercdriver7777]

Beaver Taming 101:

http://www.youtube.com/watch?v=Mji7p3MddNc&feature=c4-overview&list=UUMglwOJwgmWGbHukotknTzw

 

[hone]

Awesome video and great build thread! I'm going to pick one up soon.

You guys never cease to amaze me with the stuff you come up with :thumbup:

 

[djmoose]

Thanks so much for this. My Beaver is coming along very well. Backyard fun to take place this coming week!

 

[Enterprise]

Just finished my quad flap modified CTB. Maiden should happen tomorrow.

 

[SnowDog]

That is so awesome! can't believe - flaps on that thing...it should be sweet!