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[benbeyer]

I've been flying a QQ 69" Yak as my back up plane, but it's let me down again. So I decided to look around for something...better.

Thus I now have a 3DHS 70" AJ Slick. This should out fly the QQ Yak and plus, it's electric so there's no nitro mess to clean up.

I started by putting the axles and wheel pants on. I really like the set up that 3DHS uses. The axle is lightweight and actually clamps the pants to the gear. The gear is further secured with small wood screws. The next step is to attach the landing gear to the fuse. One thing I really like about this fuse is the landing gear plate is already covered in fiberglass cloth. This should be strong. The manual called for CA or epoxy to glue in the landing gear cover plate. I used canopy glue because it won't be as brittle and should handle the vibration of landing and taking off of a grass field better. Plus it might be easier to remove.

After the main gear, the tailwheel bracket with tailwheel goes on. Carbon fiber so it's also strong and light weight.

Finally, I went over the joining of the parts that make up the motor box and battery tray with thin CA.

[JeffT]

Sweet!
What are you going to use for a motor?

[benbeyer]

Scorpion 4025-12. I would've liked to get a Neu, but this is my first electric this size so I decided to keep it simple. The Scorpion is a great motor too though.

[JeffT]

I was thinking about the same motor for mine (on 6S).

[benbeyer]

That's what I'm running. I got a Castle 100 ICE ESC and some Zippy 6S 5000maH packs.

[benbeyer]

Moving on, I cut out the air escape holes and the holes for the wing tube, wing bolts, anti-rotation pins, and servo wires. I used a total of 5 blades for this. You can use a soldering iron, but I wouldn't use one that puts out more than 25 watts. I've always used xacto blades so that's what I used. A key to using them is to change them often. The dull easily so they must be changed often when cutting covering. I'm actually using Hobbico blades which were cheaper than xacto brand and I buy them 100 at a time. It's cheaper in the long run and you'll be a lot happier with a sharp blade than trying to cut with a dull one.

[benbeyer]

After that, I glued the rudder hinges. I use lithium grease for keeping the glue out of hinge pivot points. It's important to use some type of lubricant because if the glue gets in the hinges, you're in trouble. I apply it with a bamboo skewer because it's cheap and has a nice point. After I apply grease all the way around the knuckle, I work them back and forth to get it into the knuckle. You can use liquid lubricants, but then you have to worry about getting too much and then removing it all so that you get a good hinge/glue/wood bond.

The glue I use for hinges is the Pacer Hinge Glue. Unfortunately, it's being discontinued. I've used epoxy and poly glues in the past and I can tell you once I tried this, I don't want to go back to using them. It cleans up with water, has a great bond, and doesn't foam so you don't have to clean up excess glue for an hour. Tony Russo of Dalton Aviation told me about this glue and if Mark Leseberg's hinges don't pull out, I'm confident mine won't. Either way, always make sure you get a good bond. I want to do some test of this glue vs. wood glue because it might hold just as well, but I want to make sure first. I plan on doing that so I know if I can use it in future builds.

I begin by putting a small drop in each hinge hole on the vertical stab. I then put a small drop on the end of each hinge and put it into the hole. I wipe of excess with small pieces of paper toweling and I keep a cup of water handy in case I need to use it to clean up excess glue. I then put a drop of glue in each hinge hole in the rudder and a drop on the protruding end of the hinge. I then slide it together and wipe any excess glue off. In this build, you must make sure that you account for the tailwheel tiller arm. If you miss it though and don't want to undo what you have done, you can always take off the tailwheel bracket, provided you only used blue loctite, and slide the arm through the ball link in the rudder for steering. Continue to work the surface back and forth every so often to make sure you don't have glue in the hinge knuckles.

[benbeyer]

I got a little work done tonight. I began by getting the horizontal stab in place. To do this, I put the wings on the model. I've seen some people use the wing tube, but I want the stab to be in line relative to the wings. The first step is to get an equal amount on both sides of the fuse. I then measured from the tip of ailerons to the trailing edge of the stab. Once the measurements matched on both sides, I put a few drops of thin CA to hold it in place. I then sighted down the fuse and adjusted it to where it was level relative to the wings. Once everything was set up, I soaked the joint with thin CA. In the past, I've removed the covering from this area, but decided not to this time since other people don't seem to be having a problem.

After that, I worked on the motor and ESC. I'm going with a Scorpion 4025-12 and Castle ICE 100. The motor comes with bullet connectors, but on something like this, you want to solder them together. I bought some 1/4" heat shrink tubing from the hardware store to put over the solder joints. Also, you want to de-solder the male part of the bullet connector from the motor, do not cut it off. Scorpion apparently puts something on the wires and will effect the solder joint.

I then mounted the motor. There are 4mm bolts included to do this. I then put a piece of split fuel tubing on the front so the wires won't rub on wood and damage the insulation. I then mounted the ESC. I also put pieces of split fuel tubing on the wires going to the battery to keep them from being damaged from the fuse. I slipped on the cowl and my motor will need some spacers. I will get them and add them later.

[benbeyer]

I worked on the elevator hinges tonight. I used a slight different process than the rudder this time because of the way the elevators are joined. I began by putting a drop of the hinge glue into the right elevator and not the horizontal stab. I then put a drop of glue on each hinge and slid it into the hole. After this, I put a drop of glue into each hole on the right side of the horizontal stab. I then put a drop of glue onto the end of each hinge. Then came the tricky part of joining the two surfaces. I pushed each hinge into the 90 degree position and slid in the elevator joiner into the pre-cut slot for it. I then got a small working angle and put each hinge in one at a time. As the two surfaces game together, I pushed the hinges in deeper and worked them back in forth when I had them in the right position.

When it comes time to do left side, it won't matter if you the left elevator or the horizontal stab. After I applied the glue to the hinges and put the drops of glue in the holes, I put some Titebond into the slot for the joiner. The manual calls for CA or epoxy, but I prefer wood glues. Easier to deal with and cleans up with water. Don't put in too much glue or you'll have a big mess. The parts have a good fit so a nice amount of glue spread in the entire slot should hold the parts together without making a mess. I had to hold the right elevator up while I slipped the left elevator on. Once everything is in position, I worked the elevator back and forth, taped the elevators in the neutral position, and added clamps while the glue cures. Before doing this, the elevators were at different positions. Since only one servo drives the surfaces, you need to make sure they're in the same position. Sure aileron trim can correct the roll for straight and level flight, but the airplane won't fly maneuvers correctly.

[benbeyer]

I got the cowling mounted last night. I use a different method just because I feel the results are better. One thing I did was get some small #4 bonded washers. I put these between the cowl mounting screw head and the outside of the cowling. This will keep the screws from backing out and allowing the cowling to move around and get damaged from the mounting screws.

One thing I've read is that it is hard to use the collet type adapter with the Scorpion motor and a plane this big. The fix is to take some fine sandpaper and use it to scuff up the motor shaft. Other people have used 600 grit but I used 400 because I had it. It still feels smooth but will provided enough grit for a little blue loctite to help keep a grip between the shaft and the adapter. I put the collet on and rotated it around to spread the loctite. I then tightened the collet adapter down with the prop. You must hold onto body of the motor to tighten the adapter down. Once this sets up, you should be able to use the spinner with adapter. If it won't hold, I'll upgrade to some red loctite.

I also need to reverse the rotation of my motor. Since I don't feel like unsoldering the wires, I'll just wait for my CLink to come from Castle and reverse the rotation in the ESC.

[ryanm]

Good choice on the motor, I'm flying that on the 68" Velox, and a local friend of mine has it on a 70" Slick. Plenty of power. Though I have found that knife edge spins and even extended flat spins can heat the motor up quite a lot. There was even a couple of people that reported burning up the motor on rcgroups. I was pretty diligent about checking my motor temp on the first 20-30 flights and found it normally to be in the 110-120 degree range. One day I did a couple of knife edge spins and landed right after and found it above 180, so be wary if doing a lot of high throttle low airspeed type of things.

They guys on rcgroups created some scoops out of a 2 liter coke bottle and glued them onto the cowl. The scoops directed airflow directly over the Scorpion and they noticed an immediate 15-30 degree reduction in motor temperatures after doing that. This summer if I still haven't managed to crash my Velox I'll probably add the scoops as the ambient air temps are frequently in the 90-100 degree range and I expect the motor temp will go up a good 30-40 degrees as a result.

[benbeyer]

Yeah, I'm going to be making some scoops. I don't want to burn up any motors.

[benbeyer]

Well guys, been busy with the holidays and I was in New Orleans for meetings and such. I did a little work today and got the RX mounted and bound and installed the servos. My RX is the JR 921 and I'm just using it because I had it. I put the satellite RX mounted in the turtle deck. The servos are Hitec 5945's just because I had them in my QQ Yak. I used the #3 servo screws from microfasteners.com to sercure them.

[Skylane]

The plane is looking fantastic! Good work! Can you still get that Hinge glue your using? Do you know of a suitable substitute? I'd really like to give it a try, I've given up on using Robart hinges because I can't find a glue I like to use with them.

[benbeyer]

You may have to shop around to find some. I haven't tried any substitutes but it's a shame they did away with it.

[benbeyer]

I got around do gluing the control horns. I like to start by putting them together in a dry run and I use the bolt through the ball link to keep everything in line. I mixed up some 30 min. epoxy and added some milled fiberglass. This isn't necessary on something this size but it adds strength and working time. I was able to do all five control horns with time to spare with one batch of epoxy. I apply the epoxy mix to the lower part of the horn that goes into the surface. You don't need to apply an excessive amount but enough to cover the parts. I then just pushed it into the opened up holes for the horns. When doing this, I have a cup with rubbing alcohol and Q-tips ready. I use the ends of the Q-tips dipped in the alcohol to wipe away the excess epoxy. I use one to get the bulk and then two ends on another one to finish cleaning it up.

[benbeyer]

After the control horns, I moved onto setting up the controls. I'm using the HP21 programmer via my computer to program my servos. Make sure you get enough of the pushrod into ball link or you'll have control linkage failure and goodbye airplane. After the elevator was set up, I moved onto the rudder. I followed the instructions for the pull-pull in the manual. I normally use kevlar pull-pull cables, but decided to stick with what came with the airplane this time. I used a clamp to help hold the servo arm in place. I also used a piece of tape to hold the rudder in the neutral position. I like the 3D hobby set up because I can get things tight with minimal adjustment. I usually use the SWB pull-pull tensioners but this way works really well. I then programmed the rudder servo.

[benbeyer]

I got some more work done today. I began by setting up and programming the aileron servos. I use some protractors that I print off the internet for this. They help me determine how long to make the control linkage and also to make sure both servos (even though they're in different wing panels) move the same distance over the same number of degrees of throw and thus match each other. With the way the servo and control linkage sit relative to each other, it's not ideal in that I could never get the amount of movement for up and down on the aileron itself to match X degrees of throw on the servo. I have the linkage set up for 11cm up and down over 65 and 80 degrees of servo arm movement, respectfully. Ideally, I would want to get the same amount of servo arm movement for the 11cm of up and down. You'll also notice how I set up my ball links on the bottom of the servo horns. I did this to minimize the stress on the servo at full deflection and so I wouldn't get any binding through the travel. There is little stress at neutral so you want to put as little stress as possible and high amounts of throw.

After that, I worked on getting the RX battery installed (pics later) and the motor cooling scoops. I used the top of a 2 liter bottle for this. I'm not a big soda fan so I just bought whatever was on sale. To figure out how large to make the scoops. Just estimate by aligning them on the front of the cowl. I also used canopy/lexan scissors to clean them up. I have canopy glue curing to hold them in and I hope they're good to go tomorrow. I'm planning on test flying the airplane tomorrow. I just need to set the CG which won't take long.

[maineflyer]

Looks great!!

[benbeyer]

Well, the glue did not fully cure last night so no maiden today. Tomorrow is a school holiday but I have stuff to go do at our lab so I'll knock off early and I may run out to the field to try to get the maiden in if the glue finishes curing. Here's a few more pictures though.

I will add more velcro to the battery area as necessary when I do the CG. I just put a little in for now. I will also have some velcro straps to help hold the battery in place. I'm thinking of doing two but may just try one.

[JeffT]

Well.... we are dying to know - did you get the maiden in today??

[benbeyer]

Unfortunately no, glue still isn't dry. Maybe next weekend but we'll see.

[jbdww]

Have you maiden it yet?

[benbeyer]

Nope, the weather has been bad the past few weekends. I'm hoping for this weekend.

[benbeyer]

Well, I finally had a chance to maiden the Slick today and it flies very nice. It needed very little trim and has very little coupling that will be easy to mix out. I only had time to do 3 quick 4 min. flights on it but this one is a keeper. It presents very well and the Scorpion is no slouch power wise. I started out tail heavy and kept moving the battery pack forward. I think I got it spot on the third flight, but it was windy. The plane also feels very light and I didn't do anything to keep the weight down. You could fly this at a heavier weight without worrying about killing the flight characteristics. Some guys been flying it with 3700 maH packs and I can't imagine how light of a feel that would be. I wouldn't want anything smaller/lighter than the 5000 maH packs.

Oh and the scoops work great. The motor was cool enough to touch and just slightly warm after each flight.