|Sep 01, 2014, 10:01 AM|
Ranger EX Build Log
First impression and things I noticed while putting the plane together.
This is my second plane from FPV models, the first one being a Skywalker back in November 2010. Nothing has changed. They still have excellent service.
I ordered the PNP version because I don't have access to hobby shops. Hobby King just recently opened a warehouse here but I haven't tried ordering from their site yet. I can't even order from Hong Kong because they won't ship to the mainland.
What I like:
Air intakes. I won't have to cut up the fuselage like I did for my other planes.
Air exits. Whoever designed the fuse was correct in making the exits larger than the intakes.
Whoever made the decision to make the flap servo pockets the way they are should be commended. He bucked the system but he was right, so instead of using 2 channels for flaps, I only need to use one now. The servo pockets both face the same direction unlike the ailerons which face in opposite directions. Although I usually put in digital servos and could reverse the throw on one, this is a welcome mod.
And the access slot to the servo horn screw is another nice touch. The designers should have done a little bit more and make the cutouts for the servo arm movement with the pushrod in place.
I also like the plastic channel at the bottom of the rudder for the tail wheel tiller (more on this later).
I like the pushrods' threaded portion. They are very coarse and the clevises won't slip off. The rudder and elevator pushrod lengths are fine but the aileron ones are short. With the servos centered, the clevises only thread in halfway. Supplying clevis bands was also a nice touch.
The plastic fuselage is very roomy inside. I don't have to coddle it and worry about hangar rash.
What I have concerns about:
The black canopy piece will not stay in place. On a high speed taxi run, it almost blew off. Now I have to device a locking mechanism to keep it in place while allowing me access to the canopy latch.
The servos that come with the kit that are to be used for the flaps aren't strong enough. The plastic gears can easily strip with the load exerted by the flaps. They should be the same servos as the ones on the rudder and elevator. In fact, I would prefer the same metal gear servos for the ailerons, then I wouldn't have to change them out.
Rudder and elevator extensions were provided in the kit. The problem is they are 3" too short so I can't put the rx on the plywood tray.
The elevator requires stiffening. I haven't flown it yet but if I hold the tip and give a control input, the elevator warps and this could reduce the amount of surface area that deflects the air to help pull the plane out of a dive.
Stickers won't stay stuck especially at the wing leading edge, and my plane has not flown yet. What more during flight? I try to smooth them down, but they still curl up after a short while. They're called stickers for a reason.
Although the aileron live hinge is excellent, the elevator and rudder hinges are another matter. They are so thin that they can rip off in flight.
During taxi tests, the rudder hinge started to tear. So I'll have to put in plastic hinges. With the rudder horn so far away from the end of the hinge, it is exerting a force that started the tear.
The plastic channel where the tail wheel tiller is supposed to reside in cannot do its job because the tiller is too low. I don't know if this is true of all Rangers, but this one keeps on popping out and once I have no steering, the plane will go wherever it wants.
I'm not sold on the motor side trust angle. I lean more to the opposite side, meaning the motor should point towards the right side of the tail, but I may be wrong. Once I get the tail wheel sorted out, I'll know more.
Whoever decided to make the fuse out of plastic was correct in implementing it. The only problem is it is heavy so balance is an issue. They should have made the nose longer to compensate for the weight behind the c.g. So, other than the rx, all electronics are mounted ahead of the c.g. and it needed 2 4000mah 3S and 1 3300mah 3S lipos for the plane to balance. Lipos are sticking fwd of the plywood tray by 1 inch. I know the nose is for the camera but it would have been nice if the plywood extended forward another 2 inches.
Control horns are too flimsy for the weight of the model. They should have used the same ones as the Skywalker's. They're available from Hobby King and when mine arrive, I'll be switching them over to the more robust ones.
The plywood tray in the fuse has 4 screws to hold it down although I think it is glued in place. The screw heads could present a problem if the lipos rub on them and cause a puncture. I will have to cover them or remove them entirely and just glue the tray to the ply structure underneath.
Like I said, the fuselage is roomy, plenty of space inside. Too bad it can't be used because the weight of any equipment that goes behind the c.g. will have to be compensated for up front. That video tx platform behind the motor is useless. I can't put my tx there because I have to put a corresponding weight up front and the plane just keeps on getting heavier.
What I did during assembly:
The screws were missing for the landing gear attach so I bought allen head bolts for them.
I replaced the screws with allen head bolts for the tail assembly.
I replaced the screws holding the motor pod with allen head screws and used nuts inside the fuse. Somehow during assembly of my kit, two of the self tapping screws were tightened a tad too much and the plastic stripped which required my replacing them, so I replaced them all. I used Locktite on the nuts to keep them from coming off because its close to a high vibration area.
I also balanced the prop. I usually use nail polish on the prop but I didn't have any so I used super glue and accelerator. Not wanting to affect the smoothness of the blades, I built up the superglue on the hub opposite of the heavy blade. I found out that it was also hub heavy on one side. It doesn't look pretty but now I can throttle up without any vibration at all. If I had nail polish, I would have painted the tips and not used as much to balance the prop.
With the aileron servo arms installed and cycled, the foam needed trimming so as not to interfere with the arm movement. It would have been another nice touch if they took this into consideration during design.
I replaced the Deans connector with my preferred Anderson PowerPole connectors.
Someone posted that it is rather difficult to remove the aileron servos. I will try to remove mine because I would like to replace them with more robust servos.
To get the Ranger to balance, I put in 2 4000mah 3S lipos for the motor and 1 3300mah 3S for the rx and later I will also use this for the video tx.
In one of the posts I read, someone thought this would make a good trainer. I would disagree. Tail draggers don't make ideal trainers because it takes experience to take off with one. Because of the weight of the plane, hand launching also wouldn't be ideal for a beginner.
I wanted a plane I could put together and fly immediately with confidence. It needs a lot of work to get it flying safely. My taxi tests already proved that the rudder hinge could fail after a while. My immediate concerns are the rudder and elevator hinges, the elevator stiffness and the tail wheel tiller popping out of its rails.
It is still an impressive plane. I couldn't put down the fuse after I took it out of its protective wrapping. Now thats what a fuselage should be made out of.
I'll know more about the plane after I get it flying. It will be test flown in r/c mode before I install the fpv gear and auto pilot. Right now I'm just bummed that after rushing the assembly, I have to take it apart to make the mods.
Why do you think the Skywalker was successful? Because it was almost perfect. A few complaints here and there but they were few and far in between. Through word of mouth, its performance sold itself. A company's PR dream. They couldn't keep up with the demand. Then they went with the longer wing, an in between wing, single spar, a different tail. Talk about a dream turning into a nightmare. The best of them were versions 2 and 3. I know, I bought 3 of these. I wanted to upgrade but after hearing of the problems related to the new designs, I started looking elsewhere. Now they're going back to a T-tail, but they already lost me as a customer. If only they kept the twin spar and just made those spars longer.
Right now, I wouldn't be a Ranger repeat customer. I bought a Skywalker ver 2, 2 Skywalker ver 3s, 2 X-8s, 2 Sky Hunters, 2 Falcons, 2 Sky Surfer 2.4s. I bought multiples of these because they were easy to assemble, fly and didn't have any bad vices. If the Ranger just didn't require so many modifications, it wouldn't be hard to say I want another. Because of what I'm going through, it would be difficult for me to recommend the Ranger to friends.
I am also hesitant to put in my auto pilot and fpv gear. Once I get it flying, I might change my mind. But I'm going to wring it out in r/c mode first.
What would be great to see in a Ranger upgrade:
Make the stickers optional. Include them in the box, but don't stick them on. This also reduces manufacturing cost.
A longer nose so it wouldn't take a 10,000 mah 3S to balance the plane w/o equipment behind the c.g. Sure there will be guys out there who want to go for duration, but then there will be a lot more who want to fpv close to home or even just an r/c plane. A three inch longer nose would work and satisfy both ends of the customer spectrum.
A trike version. Now this would really be the envy of other fpv/uas planes. Also no more complaints of yawing to the right. No more complaints of nose overs.
Better servos for the wings.
A reinforced elevator.
Modified molds so that the rudder and elevator hinges are a shade thicker. Its just a matter of running both the left and right molds through the CNC router to reduce the material a bit (sure it takes some programming) so the live hinge is as thick as those on the ailerons. BUT if the molds have been chromed, forget it. Put actual hinges. (This increases manufacturing costs, but hey, its an upgrade)
More robust control horns.
5mm to 7mm longer wing servo pushrods.
Till my next installment: Mods
|Sep 01, 2014, 10:02 AM|
There are excellent Ranger build threads in the forums. I won't duplicate their work. I will concentrate more on what modifications I will be doing to it to get it flying. I will include my observations on its handling characteristics in r/c mode.
|Sep 02, 2014, 01:20 AM|
Wheel assembly mod. I didn't have spacers so I used a nut instead.
|Sep 02, 2014, 01:40 AM|
Here's the tailwheel and tiller channel beneath the rudder. When the tail wheel skips during taxi or take-off, the tiller arm drops down and pops out of the channel. This causes the plane to veer away from its intended path. Without steering, the plane eventually ground loops into a semi doughnut and if the speed is high, it tips over and the wingtip grinds on the runway surface.
|Sep 02, 2014, 03:44 AM|
Germany, RP, Weißenthurm
Joined Jun 2013
You have to rehinge the ELE and RUD. Dont fly it without these changes; the big controlsurfaces surface leads to a lot of pressure
|Sep 02, 2014, 03:58 AM|
I knew that. Thats why all the taxi tests and my being bummed at having to disassemble the plane. I'm going to stiffen the elevator also.
|Sep 07, 2014, 03:25 AM|
Use your preferred method of hinging and the hinge type. I like the pinned hinge type because it is stronger than the CA easy hinges. The pic shows the alignment of the hinges. To prevent binding, get it as straight as possible. Fortunately a hinge line remains after cutting off the live hinge so I didn't have a difficult time drawing a center line. If I had to do it over again, I would use 4 hinges instead of 3 because I used Dubro small hinges, not having the standard size on hand. Once the glue/adhesive is dry, make sure to do a pull test so there won't be any surprises in the air i.e. the rudder coming off.
|Sep 07, 2014, 04:05 AM|
I did not sand off the live hinge, just cut off an area where the hinge will go. The live hinge provides a seal for the gap.
My mistake was making it like I would an acro plane, no gaps. I made an aluminum hinge that would support the lower portion of the rudder. After gluing the hinges in place, I tested the rudder on the fuse and the ugly gap at the bottom that was there before is now gone so the aluminum hinge can't be used. I wasn't following my plan and went on hinging in my normal fashion.
|Sep 07, 2014, 04:18 AM|
Tailwheel Tiller Mod
Materials for this mod: a toothpick and a small rubber band. This mod complicates disassembly because I have to remember to remove the rubber band before pulling off the rudder. I forgot twice, and the plane hasn't flown yet.
I choose a bamboo toothpick due to its ability to bend before breaking. The rubber band is what girls use for tying their hair.
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