The PAU Edge 540T

I have built and sampled most all of the major 3D plane manufactures except PAU (Performance Aircraft Unlimited) so after I was given the opportunity to try one out at a substantial savings how could I say no.  I spent a little time talking to Herve the owner of PAU at a recent huckfest where I acquired this plane. He described some features and thoughts that went into his planes and the importance of his quality control. Herve is very approachable and ready to assist with any concerns, to my surprise he telephoned me twice after I returned home with the plane just to check if I had any questions and check progress. He also offered up some helpful programming to make the plane fly to my style.

Opening the boxes

Everything was packaged very well in comparison to other manufactures. The boxes were double boxed and lined with thin wood. Any damage that may occur during shipping probably could not be avoided by the manufacture. There is only so much they can do to protect it and if the shipping guys want they can put some pretty big crunches and holes in boxes. After a quick inspection it appears the QC is very good, I like the fit and finish.

 

Wheels and Tail Wheel

I started with my signature build part as I always do, the “Spats” that I put on all my planes. The main gear is very light but strong carbon fiber and I was very impressed with the paint quality on it compared to some other manufactures. I weighed the supplied wheels against the White Rose wheels I intended to replace them with. No gain of weight loss was noticed on the tail wheel but the main gear White Rose wheels were heavier due to being made of aluminum and not plastic but that weight gain was offset by the light titanium axels from White Rose I am using so no change in weight with the bling. I should note that I am not trying to build ultra-light but more durable and still maintain a respectable light weight.  I had to modify the Spats a little to fit the gear by trimming the top ¼”.

The fuselage is already drilled with blind nuts installed for the tail wheel. After marking the location of where to drill the holes in the tail wheel I used lock washers and Loctite to secure the unit. After I install the rudder I will connect to tail wheel tiller arm to it. 

 

 

Engine

I already had a DA 120 for another plane and decided to use it in this one but I am thinking it’s a bit much. For one thing it is a very tight fit. As usual I will be using Pro Flow 3D canister mufflers for best sound and transition.

So I made a template of the engine mount and transferred it to the firewall aligning it up with the already provided center mark. This was very easy and having the pre-installed firewall made it even quicker. The necessary distance I need is 7 ¾” from the firewall to the spinner back plate so I am using 1 3/8” standoffs from SWB.  The firewall comes mounted so the correct right and down angle thrust is already set for you. This is a step I have spent hours with on other planes. 

The next step was to remove the canister opening in the fuselage firewall. With about 10 good cuts of the exacto knife it popped out easy.  I made a re-in forced mounting plate for the can mount out of ¼” plywood. It measures the width of the fuselage by 1”. This will help keep the mount secure under the notorious vibration of the DA 120. A small amount of epoxy was all it needed.  Next I prepped the engine box for paint by using some wood filler and sanding the area with 220 grit. A light coat of primer and one more pass with the sandpaper before applying the white finish coat.

The engine mounts at the very top of the firewall so it was necessary to trim the standoffs and rear fender washers to clear the top of the engine box.  With the engine mounted I started on the throttle servo. For the proper feel on the radio stick I put the servo in the half way position and the carb in the half way spot also and then make my pushrod, this gives a very accurate feel on the radio of where the throttle position is.  Any necessary programming is based on the center spot of the carb and throttle.

I decided to minimize the holes in the engine box and drill one larger hole for the fuel line and servo wires.

 

 

 

Hinges

PAU uses Robart style hinges that need to be glued carefully in-place.  There are a few different ways of installing them and the fallowing is how I like to do it.

First I make sure they all fit in place and work properly. Then I take the hinges and fold them. I hold them with the tips up while placing a couple drops of grease or oil on just the pivot hinge part itself. This way no oil can run down to the part that will be glued. If you get oil on the part that gets glued be sure to use denatured alcohol to clean it but keep the oil on the hinge part so the epoxy does not glue the actual hinge pivot point.  I sanded a Popsicle epoxy stick to a more narrow shape so I could force glue down into the holes. I use 30 minute epoxy to do this, it can take some time to get everything lined up, cleaned up and working correctly. I slide the rudder or whatever part I am hinging on all the way and move it back and forth several times making sure to get a clean 45 degree turn on the surface. Then I use denatured alcohol to clean up the excess glue and hinge pivot point. Lots of Q tips come in handy here. I continually check to make sure the hinges are working and do not need to be cleaned more while it is drying.

I do not recommend gluing the hinges into one side at a time. If one hinge is rotated off center just a small amount it will bind during the rotation and trying to remove a glued hinge is near impossible. If for some reason a hinge needs to be removed you need to cut the hinge off flush, drill a new hole and place a new hinge in the hole next to the cut off one. Trying to remove the glued hinge can destroy the balsa. 

 

 

   

Rudder cable and servo

I like using push/pull on the rudder with the servo in the tail but on this plane I went with cables. PAU supplied all the ball links, cable and crimps, I added the heat shrink just to clean up the connections. After taping the rudder in place I centered the servo and with power to the servo to keep it in place I made the cables starting at the servo. The cables are crossed half way down the fuselage. With the wire attached to the servo I snugged the wires tight on the rudder and crimped them and then slid the heat shrink over the connection. When the rudder is turned by the pull cable the other cable goes a little slack. This is normal but it’s also what I don’t like about cables. In certain maneuvers the rudder can bang back and forth putting hard ware on the servo gears. Direct linkage does not leave room for slapping the servo gears. 

Elevators

The elevator servos are mounted inside the stabilizer. A small amount of trimming was necessary to allow the servo to drop in and fit properly. PAU does a great job on the construction where the servos mount, they glue to pieces of ply together for added strength. A long 1/16”drill bit comes in handy here. I like to use a drop of thin CA on the screws when I install them in place. PAU supplies all the hardware for all the servo connections and bravo to them they all actually fit perfectly.  

 

 

Smoke

I tapped the headers for smoke and used JB weld to help secure the fittings, this has worked very well for me in the past. I don’t know what kind of Teflon tape MTW uses on their flex headers but its crap. Soooo I replaced it with a Teflon tape recommended by my mechanic at work, he said they used this tape during the Iraq war on equipment with no problems. Heck if it could hold up over there then it should be fine on my little engine.

 

Tank

PAU does not supply the tank which is fine with me; I like the 4titude 3 line pre-made tanks. 3 lines are important; this way the main pickup line to the engine is unobstructed. The fuel filter is in the fill line. I used a 32oz for the engine and the smoke system. The smoke pump is the Sullivan Skywriter. I program it down to about 30 percent and use a Fromeco 2600 Relion battery to power it.  Mcfueler DOTS are the best fuel DOTS I have found that reliably work over extended periods of time; I have one for each the smoke and fuel. 

Switches

As always I am using the Fromeco Wolverine and Badger switches from the radio and engine. They are failsafe to on and no need for separate charge jacks it’s an all in one package. 

Cowl

I opened the bottom of the cowl considerably as I want to try and not baffle the engine at all. During the build process I debated in my mind whether or not too split the cowl. I like split cowls and I don’t mind all the screws. Some people don’t like the look of the screws but this plane already has many exposed screws with the canopy and bolts for the control horns so a few more wouldn’t hurt. In the end I decided not to split it but I can always do it later if I want. 

Canopy

The canopy is not pre-installed so I had to make a decision, either glue it with canopy glue or use screws. Neither seemed very exciting to me. Gluing can get messy and requires cutting the covering to perfectly fit the canopy. With the screws the canopy can easily be repaired or replaced if necessary but looks a bit tacky with all the screw heads. I choose to screw it on which wasn’t too bad and didn’t take very long once I had taped it into place. I used the micro servo mounting screws from RTL. I should mention PAU does a nice job on the fit and finish of the canopy hatch, it fits perfectly and snug. 

 

Wings

I am using two servos per aileron so the Fromeco Quad Current Meter makes life easy. I am using two BLS157HV servos per aileron.  

CG

As I did the initial balancing I immediately started regretting not putting the rudder servo in the tail. With the cans and smoke pump up front the plane seems very nose heavy. Sooo I mounted the batteries well behind the CG to get the plane to balance just a tad on the nose heavy side for the maiden flight.

 

Running the engine

Well she is all together and ready so I took her out to my driveway and fired the DA 120 up. I made only micro adjustments from the factory settings and topped out at 6600rpm with a Flacon 29x9 prop. I think I need to get a prop with a little more pitch. I did a test flip of the smoke switch and out came billowing plumes of smoke. Everything worked great so I shut down the engine to clean her all up for the next day until !!!!!!!!!!!! I noticed the control surfaces all coming off! What could I have forgotten on all of them? I discovered that the control horns are held together by one little screw with no nut on the end, it is only tightened down. They vibrated loos with less than 5 minutes of engine running time. I spent the next hour searching my paver driveway for tiny bushings and screws that the prop wind blew everywhere.

I have come to the conclusion that I will never use these again. Besides looking ugly with giant screw heads on all the control surfaces they have one heck of a very, very, very weak link. And by not having ball links on both ends the pushrod is not free to move as easy. I found all the screws and bushings thankfully and re-installed them with Loctite, however, only about 2 ½ turns of thread is all I could get on them. I am completely convinced that if this plane ever goes in it will be due this part.  

 

Test flight

The flight itself went very well. For the first time on any plane I have ever owned I did not need to use a single bit of trim. It flew straight as an arrow. I put it into a few good maneuvers and it performed well. The plane feels like it is better for hi energy 3D and not as floaty as my other 100cc plane. It does a very good knife edge and requires very little mix.

Final thoughts

All the trim colors were barley ironed on and I had to go over them again with the iron. The wrinkles are very normal and will happen when shipped in a hot container around the world.

I will not use the factory control horns again.

The plane is very well built and strong. The fit and finish of the wood is very good.

The plane fly’s very good and will do any type of 3D. It even made me look pretty good.

Customer support after the sale is extremely and I mean extremely good, Herve waste no time in helping or answering any questions.

I recommend this plane.