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Wednesday, March 23, 2011

Extreme Flight Edge 540T EXP__The 4s Report


Well, here's another report that is going to be just a little bit different. In our last report, EXTREME FLIGHT Edge 540T EXP__The 3s Report , we ran so long that I had to split it up into a 3s report, and this 4s report, with set up and equipment information. I guess I got so carried away gushing about how well the Edge 540T EXP flies that there was no room for the other info.

And thusly, this is the 4s report. Ken is on a Caribbean cruise with his lovely wife, so we are two weeks away from having video, but for now, we've flown the plane and can report our findings.  After the flying section, there is set up info and photos.


EXP series planes were designed to be flown primarily on 4s batteries. Some guys don't like that much power, so the EXPs were designed to fly just as well on 3s, though they do fly differently. Pick your batteries based off the flight characteristics you are after.

For example, I love the Extra EXP being gentle and easy to fly on 3s, so I fly my blue one that way. But I also love the Extra to be fast and bad ass, so I built a red one to fly on 4s! The MXS, being it's own dog, is bad ass all the time, so it gets nothing but 4s all the time.

But, you get the idea: 3s is for relaxing run and easy 3D, while 4s is just for being badass.

While I immensely enjoyed my Edge 540T on 3s, I learned from the Extra 300 and MXS how 4s packs makes the EXP series planes come alive. Additional power does virtually the same things to all the EXP planes, so I am going to say much the same things as I did on the MXS 4s report.

Most obvious is blistering top end speed, but that works to make the Edge easier to fly because it locks itself hard into a solid groove.  Almost all planes groove better at higher speeds, but the the massive throws and rearward CG you put on a 3D plane definitely works against smooth high speed flight. Part of where the EXP series shines is high speed smoothness and stability in spite of running a full tilt 3D set up. Most of the time I don't even bother with my rate switch when I move from 3D into a precision sequence. The EXPs are so smooth and solid that you can do precision on high rates. Since the EXPs are so stable, precise and groovy anyway, making these traits even more prevalent with 4s is a good thing.

For me it is hard to get used to a plane doing such excellent 3D, and then having no skittishness at high speeds. It's too good to be true, so at first it is a little spooky. It's so good that it must be a trap, and you are waiting for it to bite you ... but it never does.

At speed the EXP's are very much like the old AMA pattern planes that we used to fly at full tilt speed through all our maneuvers. They get up to speed and they don't want to change direction, as if they are flying on a giant, invisible rail. We like to say the airplane grooves, as if it is flying in a groove, and we like to say "locked in," and these terms very much apply to how the EXPs fly at higher speeds on 4s power. They are even pretty locked in on 3s too, but 4s puts them in another world. I have flown some planes that are pretty good at both ends of the speed spectrum, but the EXPs, to me, seem to be the best at both ends.

While the Edge powers out of a hover respectably with 3s, there is a definite rush to blasting out with devastating 4s authority. When you hammer the throttle it is almost like lighting off a D series Estes rocket. This kind of power is a little harder to handle in harrier and hover, but the flip side is that if you get it wrong, you have plenty of grunt to bail you out.

Finally, one of the big rushes of 4s power for me is the instant blinding acceleration. Part of the beauty of extreme aerobatics is the ballet of speed extremes, and the violence, suddenness and surprise with which you can go back and forth. For awhile we have been using hard rotation maneuvers to quickly dissipate speed and energy, but with Torque motors and newer higher discharge batteries, we are getting that speed back nearly as shockingly.

That, and a bad ass airplane is just plain fun.


Having already built one Edge 540T EXP, two Extra EXPs, and two MXS EXPs, this plane didn't have any surprises for me. Every brand has it's own peculiar way of doing things, but I'll admit the EXP series is extremely similar to what I was used to from before. A lot of things are done the same way, and I believe even some of the hardware are the exact same pieces. This is good because it's all top of the line stuff.

The aileron linkage couldn't be any easier. Screw the ball links on both ends of the push rods and then bolt the ball links to the control horn and servo arm. I always use Dubro 2mm hardened allen bolts simply because I like the way they look.

In the only complication of the entire build, I had to snip approximately 1/16" off one end of each aileron push rod because they were too long. I like this because it means the threads are buried so deep into the ball links that it would be almost impossible for them to pull out.

By using the long single arm that comes with the HS65MG servo and cranking the end points on my transmitter, this is just the perfect amount of aileron for my flying style. This is the same on all three EXP series designs. I like them all set up exactly this way.

One place we deviated from the manual on this build was using an HS85MG servo on the elevator. I was getting blow back and stalling on my first 48" Edge EXP. I believe airframe performance has increased to the point that in some cases the HS65MG servo is marginal. With the EXP series' huge elevators and big movements, we need a little more torque.

Since the 85MG is specified and works so well on the MXS, we decided to try that on my Extra EXPs. The HS85MG has worked out so well on all of those planes that I knew it was the right way to go on the Edge 540T as well.

We only had to trim the servo opening a little bit, but it was worth it because this is a big upgrade. One thing to be careful of is to remember the push rod is set up to be the right length for an HS65MG servo. If you just cut the servo opening forward, the whole servo is going to move forward, and with it, the servo arm. Then your push rod will be too short. I made this mistake on my first Extra EXP, and since, I have made sure I mark where the servo output shaft sits when I put an HS65 in the servo opening (fore/aft wise), and then I cut the opening so the servo output shaft on the HS85MG sits in the same place.

Another thing to be careful of if you choose to go with the 85MG servo, check the servo arm clearance to the stabilizer before you drill the holes. You may have to drop the servo down a bit so it doesn't hit. Ours fit, but it was close.

The HS85MG is only a slightly bigger servo, but it has got a lot more torque and will not stall on this plane. The HS85MG simply refuses to take no for an answer, and you get instant, full deflection even in moves like full throttle walls and terminal velocity parachutes. With the 85MGs greater torque, you will be able to get the most out of the Edge's outrageous elevator authority.

Again, ball links on both ends of the push rod gives you a nice, tight connection that is free of slop, but with smooth, drag free operation. First class set up.

Dual Ball links on the rudder linkage gives a nice, smooth action and full travel, with excellent centering. As you can see, I got away with using the standard arm that comes with the servos.

Like this I didn't get a chance to try Extreme Flights' most excellent G10 servo arm extensions. I was a bit disappointed because they are simple, functional, well engineered and well made pieces. I always like to use stuff like that. I used one on my new MXS rudder servo, and it works perfectly and looks awesome.

Here is a close look at Extreme Flight's exclusive G10 servo arm extension. I used Durbo self tapping button head screws to attach the extension to the standard Hi Tech arm and then ran a bead of thin CA all the way around the arm to lock it down really tight. The kit comes with two of these, one for rudder and the other for elevator. These arms give you as much throw as you'll need to make the Edge stand up and bark.

As of this writing I am satisfied enough with the rudder response. The Edge 540T can do full throttle knife edge loops without needing full deflection, so I don't think I need any more. Initially I was worried about blow back simply because the rudder is so large, but I have a secret weapon in the new Airboss 45 ESC that now runs the servos on 6 volts. The little 65MGs scream their guts out on this much voltage and torque is much improved. I need a little more time to fly the plane and see what we have, but as of right now I don't see a need to change the rudder servo out for an 85MG.

Radio Installation
I really like the way the radio compartment is laid out in the EXP series, simply because it's easy to get a clean install. I put the receiver where the manual says, run the wires up through the slots cut in the tray, and always comes out perfect. Also notice how the braces on the formers make a nice little place to run the servo extension wires through. This keeps the wires from flailing around and beating themselves to death.

There is no scientific proof that a neat and tidy installation makes a plane fly better, but I sure feel better about it when the install comes out this clean.

Power System

Torque 2814
Using the Extreme Flight power system with Torque 2814 motor and Airboss 45 ESC makes for a clean installation. All EXP series aircraft are designed for use with Torque motors. The firewalls come pre drilled with blind nuts pre installed so the Torques bolt right no with no fuss. The cowlings also line right up perfect with these motors.

While the fact the planes were designed for these motors is reason enough to use Torques, you will also not find a smoother, more reliable power plant. We have been flying Torques exclusively for four years and they have been golden. I fly them extremely hard and they take the abuse with no problem. Some of my Torques are the original units I bought four years ago, but I swap them around so much I have lost track. Not that it matters....I'll put any Torque I own into a brand new plane and never give it a second thought.

Airboss 45 Elite ESC
We have a new secret weapon in the latest Airboss 45ESC. A while back Extreme Flight reprogrammed the Airboss to operate on 6 volts, meaning that's how much voltage is going to the servos. Before, the servos were getting approximately 5.22 volt, but bumped up to 6V, all the servos absolutely scream.

I have been saying for a while that airframe performance has made so many quantum leaps that the original HS65MG servo is getting close to being marginal. In addition to blowing back elevator servos in parachutes and such, high speed roll rate would suffer, and KE loops were dicey because of rudder servo stalling. Bumping the Airboss' voltage up to 6v has cured this problem.

Before, my KE loops were always a bit lame because I had no faith on the downside. In retrospect, I was stalling the rudder servo, and like that you can never be sure how much control you have. Now, with the 6V Airboss, my KE loops are round and low to the ground. My whole KE game has gotten better because I have a new found faith and control, due to the new Airboss.

Adding to the airboss' legendary "plug it in and fly" simplicity, it now comes with a Deans plug already installed! Truly, you just plug it in, put the cowling on and forget about it until the airplane is worn out. Then you just move it to a new plane and start over!

The Airboss 45 will run on 3, 4, and 5s battery packs, and it does it automatically. The Airboss auto detect feature knows how many cells your are running and adjusts the low voltage cut off accordingly.

Unchanged is Airboss legendary reliability. I have been torturing my new Airboss units without giving it a second thought. These are the only units we run on our 48" class planes. I also run these on my 40" class planes, because even little planes need reliability.

I am not sure how to tell the new 6 volt Airboss from older units outside of the wires for the switch are longer. This is presumably so you can mount them on the bottom of the EXP series plane's motor box (as called for in the manual) and still use the pre cut switch hole in the fuselage side.

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