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Tuesday, October 18, 2016

52" Extra EXP__Synergistic Integration


The much anticipated Extreme Flight 52" Extra EXP is finally here and is as mega as we were expecting.  As soon as I heard about this plane I started gathering the equipment up. As you may already know I have a soft spot for Extras.

The 52" Extra EXP has so many similarities to the much-loved 48" Extra that I am sure The Boss started with what he already had and added all the improvement and innovation he put into later EXPs and just made the whole package bigger. This would include features like the super strong angled side motorbox, and vertical wing bolt attachment. It's been six years since the original Extra EXP hit the runways, and everything that has been learned about flight and advanced construction since that day is incorporated, integrated into the new 52".

There are other improvements, but we can get into that later in the report. In short the 52" Extra EXP is necessary to take advantage of slightly larger high torque servos and Xpwr's insane new power system. This is, in short, another step forward in extreme performance.

Synergistic Integration
OK, this gets a little deep, but stay with me, OK?

By melding the concepts of Integration and Synergy you can combine one thing with another so that they become a whole, while you have the interaction of two or more pieces or assemblies to produce a combined effect greater than the sum of those parts or assemblies. How this applies to this plane is simply that Extreme Flight has brought together the best everything and packaged it as a quantum leap into the next dimension of 3DXA flying.

Ok, maybe I was having a little fun with you, but everything from the airframe itself, the power system, servo arms and extensions right down to the screws that hold in the servos all work together as an integrated unit to bring you unparalleled performance. 

In short: Things that are designed to work together always work better than things that aren't.

I've already previewed the Xpwr system and Xessories in separate blog articles and thought they were awesome, but when they come together in a plane they are designed to work with, the result is much, much more. While I was looking at and reviewing the individual pieces, I missed the big picture of it all coming together, but you will see that for yourself when you assemble your own and fly it.

Smokin' Graphix
Also of special note is the superb Arron Bates (The KM) custom color scheme, in outrageous red or elegant blue. To my eye, it is the perfect blend of Extreme Flight's traditional look and 3DHS' eye popping cutting edge styling, so there's something for everyone in the way this plane looks. Well done, Arron.

Worth pointing out is the integrated design of the color patterns on the wheel pants.  It's the same theme as used on the rest of the plane and it all sort of flows together. This is not normally something manufacturers pay a lot of attention to, but again the concepts of synergy and integration come together to make it all work together. The colors on the nose of the fuselage sweep back over the wing and flow off the tips. The awesome wheel pants simply complete the look. The design of the stabilizer is much the same, and it appeals to my sense of symmetry. Overall, it's simply a brilliant scheme.

 Click To Enlarge All Photos


Did I mention how good this thing looks?

There's going to be a lot to cover in this blog, considering this is nearly a new size class of plane and the equipment is all different from what we have been using for the last 10 years in our four footers. This is essentially a brand new game and a brand new level of mid sized performance. Since there will be so much information coming at once, we will post the first videos on a separate page, hopefully in a day or two depending on which way the hurricane goes!  Even with the flying left out, this is still going to be a lot of info, so let's get to it. 

The 52" Extra EXP will be the first Extreme Flight plane designed especially to use Extreme Flight's superb new lineup of quality Xcessories. You can order your Extra with absolutely everything you will need, from the beautiful Extreme Flight anodized aluminum servo arms, the correct length Extreme Flight servo extensions and even the Extreme Flight anodized titanium colored socket head screws for installing your servos. As long as you have a receiver, you can order everything you need directly from Extreme Flight, get it all in one package and only pay the postage on one box.

Extreme Flight is stocking the correct servos for this plane, so once again you can get everything you need from the X company.

There were not too many surprises here, but we were not expecting many either. Why change what's working? Outside of that, the surprises we got were good ones. A lot of cool featured we have seen on different EXPs have all been put on this one too.
Again, for this plane the Boss has incorporated everything he and the factory have learned over the last six years of making EXPs. The airframe is simply a larger 48 built to the newest standards. Instead of updating the 48, the Boss threw in all the cool new construction techniques and upsized the whole package to use more powerful and durable equipment. 
So, in as simple of terms as I can muster, this is the 48 perfected and taken to a new level. 
One surprise is that new Extra does not feature recessed wings like the Lasers and Yaks. The wings fit so beautifully, I suppose there was no need to go that way. These wings also slipped right onto the plane with zero effort. Sometimes you have to struggle with them a little the first few times you put them on and take them off, but the factory is getting really good at this, and they stepped it up for this plane.
Again, the factory continues to surprise us with it's quality construction. They have surprised us so often that it's not even a surprise any more, though that certainly doesn't mean I take it for granted. The new Extra is straight, light and built cleanly. Usually the 60" EXPs seem to be a step nicer than the 48s, but the 52" doesn't give anything up to it's bigger stable mates in the way of being perfectly turned out.

The servo holes are precut on both wings and fuselage, so this cuts out any guessing. Nothing sucks more than cutting open the wrong bay and having a hole in the side of a brand new plane that doesn't belong there, but that possibility has been eliminated. I usually like to do these myself because in the past I could do a little cleaner job, but the factory has got this completely figured out and they are now cleaner than I could ever do them. It's also nice there is one less thing to do on the build.
Also worth of note, on my Extra all four servo bays came predrilled for HS5087MH servos. I didn't have drill one hole on the whole plane except for the cowling
Holy cow, is the motorbox on this plane ever beefy! In addition to the already super stiff angled side construction, this motor box has carbon longerons running along the bottom to make it even stiffer. As is usual for an EXP, there is always plenty of Extreme Flight's G10 composite material on the face of the firewall. 
While I certainly don't recommend it (and it would surely void your warranty) this thing is so stiff I almost think you could play baseball with it! It's certainly going to be much stronger than it needs to be for anything I am going to do to it short of an outright crash.
Landing Gear Mount
Here we see 3DHS' technology filtering into an Extreme Flight plane. The Extra uses 3DHS' carbon tube method of reinforcement, Unfortunately it's really hard to get a good photo of it since it's under the battery tray, but you'll see when you built yours. This assembly is so tough that I think to rip the block out of this plane you would pretty much have destroy the whole plane. 

Wing Bolts
For securing the wings, the 52" Extra uses the tab method. A tab on the wing root plugs into the fuselage and is secured with a vertical allen bolt. This is the same system as used on the 48" Laser and Yaks, and a few of the newer EXPs. While this might not seem like a big deal, those of us who have arthritis appreciate how much easier this is than the hard to reach horizontal wing bolts as used on the 48" Extra. 
Check out the snappy wood piece that captures the aileron servo leads and keeps them from falling back down  wing.
Basically the factory went out of their way to make everything as nice as possible and eliminate as much work as they could for the builder. When you combine these steps forward with the new lineup of quality Xessories, and insane Xpwr power systems, it's pretty clear the merger with 3DHS is now fully bearing fruit. We've got the best minds in the business all working together, synergistically, of course, and it really shows up in every detail.
 With the plane being so well built and working with such nice hardware and Xessories, this is probably the nicest plane I have ever built. The whole experience gives me a new level of satisfaction.
As seen on the 60" Yak, the Extra now has plywood hooks at it's wing root to keep the servo arm from falling back into the wing. In that same there are now hooks on the formers inside the fuselage to secure the servo wires coming from the tail to the receiver
G10 is so used to reinforce the critic high stress areas on the fuselage around the wing tube and both front and rear anti-rotation pins. 
Absolutely no surprises here. Almost every piece comes straight from the 48" Extra, which is top shelf bulletproof equipment. The ball links are the same ones that have performed so flawlessly in the 48s for so long, and by now we all know how to set those up to get the smooth, drag free operation so essential for precise flying. They use a 2mm bolt, which works perfectly with the new Extreme Flight aluminum arms. This is going to make the build, set up and assembly go much more quickly.  
Also part of the hardware pack is the standard Extreme Flight carbon tailwheel assembly that I love so much. The tiller arm is now one machined piece, which will address some of the looseness we were getting after beating up the old units for awhile. 

All the nuts, bolts, axles and wheels appear to be the same stuff we have been using on the 48s, which is a good thing because I like working with familiar equipment that has never let me down. All of this sends me into the build and flying with Xtreme high confidence. 
One nice addition to the hardware pack are the 2mm lock nuts for the bolts that secure the ball links. I usually buy these from Micro Fasteners, but it's nice these now come with the kits. My Extra came with eight lock nuts, one for each end of all four pushrods. This is a very nice upgrade.
Something else I noticed is that all four pushrods are the same length, and there's no chance you can mix them up. I spun the pushrod into the ball link that I would bolt to the control horn with a drill and then spun the ball link with the control horn attached to the other end. On both ends the ball link was very nearly bottomed out, which means there's a lot of meat holding onto the treads and zero chance the pushrod can pull out.
If  Extreme Flight follows the form they used with the 48" EXPs, all future 52"s will use this hardware pack, which probably include pushrods. If you need a replacement pushrod for any reason, there's only one size. This makes stocking spares a lot simpler.
The Build
Following the manual and using some of the tricks I outlined in Miscellaneous Build And Set Up Tricks, there were absolutely no surprises and everything went together like I expected it to. Once you have done an EXP or two, assembly almost becomes instinctual, and this one is just a continuation of what we've been doing all along.
One of the really nice things about this plane is that I don't have to worry about installing a larger servo on the elevator and cutting into a brand new plane. That always went down the wrong way with me, but it worked. Now, though, you just drop one of the recommended servos in the hole, secure, and you're done. This also saved me about a half hour on the build and a bunch of stress.  
Speaking of servos, my Extra came predrilled for HS5087MH servos

I had some custom graphics made up from 3M High Performance Vinyl. It's a little expensive, but this plane is worth it. 



Power System: Motor
The motor of choice for this plane is a product of Extreme Flight's Extreme Power division (Xpwr). As you may have read in Testing the Xpwr 3910 .  When the motor first became available I wanted to become familiar with it, so I tested it in my 48" Extra and MXS. It is smooth running, cool and reliable, just like the Torque motors I love so much.

The 52" Extra and Xpwr 3910 were designed to work together as an integrated package. This motor delivers absolutely Xtreme sick power, 1068 watts at 72 amps (Xoar 14/8). When I tested this motor in a 48" Extra it was so overpowered that I was hanging on the entire time, so it ought to be perfect for the 52".

Designed to work with either a Xoar 14.8 or 15/7 propeller, the 3910 accelerates so quickly you can almost feel the plane trying to rip the transmitter out of your hands. This is the most righteously powerful thing I have ever flown.

The sound of the 3910 is a little different to what we are used to. It is quieter and sounds more like (metaphorically speaking) a Mercedes than a Ferrari. I does not quite scream like a 2814, but it's sound is a little more muted and lower pitched. Perhaps this is because it's not working nearly as hard, which leads me to believe it could be even more reliable than what we are used to flying. More reliability was certainly not necessary, but it's always a good thing.

Aside from being shorter, and bigger in diameter than what we are used to seeing in the 48s, there's really noting different in the way you install and use the 3910 in the 52" Extra. The mount appears to be the same one as used on the Torque 4016/500 MkII motors we fly in the 60" planes, so again I am happy to be working with something so familiar.

The motor simply bolts straight to the Extra's firewall (using the included X mount) with no additional fitting or cutting. You just install it the same way we have been doing all along with all the other EXPs. This is not really a surprise because the two were designed to work as one integrated unit.

Power System: Speed Controller
You were looking for a surprise here? Of course the speed controller on any of my planes is always going to be an Airboss, for this project, the Airboss 80 Elite. I've been using these ESCs in my larger planes since the dark ages and still have not had one let me down. Never change what's working. With a Xoar 14.8 prop, I was pulling 73 amps, so we have the right ESC with a little safety margin built in.

Again, with this being a completely integrated package, the motor and ESC work together perfectly. Even on fully charged 70C packs there was never a hint of squeal or hesitation, and throttle response is smooth and linear. This is what I expected from the Airboss ESC and what I've become accustomed to with Torque motors. Xpwr certainly got everything absolutely right on this package.

One change especially worth notice is that to get the best performance out of the 3910, you will need to reprogram your Airboss 80 first to default, and then add high timing. This is a simple matter that is covered in the manual you get with the ESC, or the online version.

When I run a separate BEC  do not like to use the switch. The power from the radio will be coming from the separate BEC, so the switch doesn't work anyway. If anything, it gives you a false sense of security when you plug the battery in. I cut the switch off, shorten the wires, solder them together and use heat shrink over the joint. Then I stuff it under the clear covering on ESC. This gets the switch out of the way, but if I ever need to go back to using Airboss' on board BEC, it still works.

The Extra was enlarged just enough to be able to take advantage of the power and torque provided by the slightly larger and more powerful Hitec HS5087MH  servo. I have used the HS5087MH to great effect for years on the elevators of my 48" EXPs and they are smooth, powerful and center very well. Because they have performed so well over such an extended period of time, I have zero concerns about their reliability, and I already know about their performance.

This set up will be perfect for the most extreme abuse-the-equipment style of pilots, but there are other benefits that will work to the advantage of regular every day sport 3DXA pilots.
Motor Type:3 Pole Ferrite
Bearing Type:Top Ball Bearing Support
Speed (6.0V/7.4V):0.17 / 0.13 second
Torque oz./in. (6.0V/7.4V):50 / 60 oz-in
Torque kg./cm. (6.0V/7.4V):3.6 / 4.3 kg-cm
Size in Inches:1.14 x 0.51 x 1.18 in
Size in Millimeters:29 x 13 x 30 mm
Weight oz.:0.77 oz.
Weight g.:21.9 g.
For the slightly insane over-the-edge type of pilots who love to do repeated full throttle blenders, full throttle walls and parachutes, and tear-your-guts-out type of tumbling maneuvers, the high performance of this set up is ideal because of their enhanced speed, torque and laser like centering.

The laser like centering will also come in extremely handy for precision or IMAC style of flying because a perfectly trimmed plane is always going to be more precise. This will also really help the regular every day sport 3DXA pilot because a servo that locks in and holds it's trim and centering  will make the plane go and stay where you put it. This reduces the workload on the pilot and makes him look good. We can all use a little more of that.

Thanks again to my friends at Hitec for their support and helping make this project possible.

You will need to supply 7.4 to 8.2 volts to these servos, and for this I trust the Castle 10 Amp BEC, which is fully adjustable using the Castle Link Programmer.

Extreme Flight recommends a 4s 3000-3300 mah capacity pack, so the perfect match for me is the new Thunder Power 4s 3300 70C Rampage packs. I've been perfectly pleased with my 55C Lightning packs, but I have not been able to kill any of them even through two years of blistering Florida summers. As such, I haven't had the opportunity to try Thunder Power's latest offerings, but we're going to correct that now with these Rampage packs. Being a high discharge rating means I can run them a little harder and maybe expect a little longer lifespan. Having more power is never a bad thing either.

I like the 12C charge rate because I can safely charge them at up to 39.6 amps. My Thunder Power
TP820CD charger puts out 20 amps per side, which means the bvest I can do is charge them at roughly half the maximum rate. While these packs are designed to charge at the full 12C rating, it never hurts to take it easy on your equipment.  I am guessing I can charge one of these in 10-12 minutes. If you have a 40 amp charger it would be frightening how quickly you could top one of these off!

 At 353 grams, they are not that much heavier than the 2700 packs I am using in my 48s, and light weight is always a plus. They are also not much bigger in physical size either, so you can move them around quite a bit to get your CG where you want it.

The specs below were copy/paste from Thunder Power's website. I kind of doubt I will be spiking the battery at 462 amps, so it's nice to have that much more safety margin than you really need. Under stressed equipment is more reliable and lives longer, and with money being tight, I've got to get through next year on just two packs. It makes sense to get the mega battery to start with instead of replacing cheaper packs more often.

Max Charge: 12C
Max Charge Current: 39.6A
Max Cont. Discharge: 70C
Max Cont. Current: 231A
Max Burst: 140C
Max Burst Current: 462A
Weight (g): 353
Dimensions (mm): 27 x 43 x 141

As always, thanks to my friends at Thunder Power for their support over the years. This blog and
these reports would simply not be possible without them.

Control Set Up
Using the hardware for the 48" series EXPs made this part extremely easy. Being familiar with the equipment helps, but it's pretty easy anyway. For tips on getting your ball links set up for smooth, slop free and frag free operation, scroll down to BALL LINK SET UP.

While simple enough, now it gets easier with the Extreme Flight aluminum arms that are pre-tapped for 2mm bolts. Now you just bolt the ball link directly to the arm and you no longer have to worry about using a nut and glue on the back side. Personally, I am paranoid about these things, so I'm still going to use a locking nut on the back side.

Here I am using  Xcessories' sweet 1.25 aluminum servo arms, with the ball link bolted on the next to outer hole. This is plenty of aileron throw for almost anyone and maybe a bit too much for me. I can always dial it back if I need to.

The servo hole is already cut out and drilled, so you just drop it in and secure with the Xessory Socket Head Servo Screws. Easy, just like the 48s.

Again, we use the 1.25" Xcessories arm, with the ball link on the outside hole and the end points in my transmitter jacked to the max.

I feel like I am being a bit lazy not writing more about it than this, but that's all there really is to it. The arm goes on with a little bit of gentle pushing, and if you have to take it off, gentle wiggling pops it right back off. Other aluminum arms I have tried nearly take a hammer to get seated properly, and then you have to pry them off with a screwdriver.

Once you have the servo arm locked on with the center allen bolt there is also an allen cinch bolt on the side of the arm. When you crank that down the arm cinches down hard on the servo output gear's spline and locks it on like a vice. This assures you have zero slop between the servo and the arm, which will give you a better flying plane.

Frankly, it's hard to say too many good things about these servo arms because they solve a lot of the
problems we have been having with other arms and they are a righteous addition to the Xessories lineup.

I'm still playing around with this and it may not be the final configuration. For now I am using the short single arm that comes in the PN55709  pack and it works Quite well.  I may later switch to an Xessories arm, but I ran out of them for this project. I'm still tinkering with it. it's actually almost perfect the way it is and I hate to change things that are working.

The arm may look like it is not parallel, but that's not how you want to set a 3D plane up. Since we run so much throw the arm is actually straight at full deflection. This set up gives you the best mechanical advantage.

Radio Installation
Like on the 48s, there is platform for mounting the receiver. Mountred here you can plug the servos directly into the receiver without servo extensions. My car is a bit small. The trunk is 51.6" wide, so I have to take one wing off for transport. To make this easier I simply used Xessor 6" servo extensions, but I'm going to order some 3" when I get another one of these soon.

You put the receiver here and the recommended extension for all channels are the right length almost like all of this stuff was made to work together.

Oh ..... wait. It is.

With the receiver behind the wing tube, everything stays out of the battery compartment, so you aren't always snagging wires changing out packs. You can see the little hooks on the fuselage sides that retain the wires and keep them from flopping around. This just makes for a clean looking installation, almost like I know what I am doing

Here you can see the plywood hooks holding the servo wires and making the installation really sweet and neat.

Power System Installation

Once you bolt the hardware (X mount, real collar, and prop adapter) to your 3910 Simply bolts straight to the firewall. There is so little to do there's nothing more to say!

The motorbox has two carbon rods running along the bottom. This looks like really good place the motorbox, This way the ESC is directly behind the Extra's chin cooling scoop and always in moving air. The Deans plug also comes out the other side (your choice, left or right), and lines up with the battery connection.

Worth noting in the pictures are the pre-cut slots for the wire tie that secures the ESC. Boss Hinson  thought of everything on this plane.


The 48" Extra EXP, in my mind anyway, does everything exactly the way an airplane should do it. It's behavior is perfect in every respect, so it is my baseline for comparison to other planes. As such, the 52" is bound to be the new four foot standard because it's the 48" all over again, only bigger, smoother, more solid and more precise with quantum improvements in the Xessories, power system and execution.

No real surprises except how nicely integrated everything is. I have no concerns about it's performance, and really expect that to be a quantum improvement as well, but we know more as soon as I drop the hammer and let her rip.

For now, I want to get the information about the plane out and video will follow as soon as we can get it in the can. Keep your eyes on the blog for a new video and flying article, hopefully in a day or two.

 Finally, thanks to Chris Hinson  and Ben Fisher for giving me the education, mentoring, and opportunities to bring these articles to you. You guys rock!




  1. Great review of components and the build. Can't wait to see video- this (in the 48") was my first EF plane, and probably still my favorite!! This new size will be a blast, I'm certain!

  2. Hello Doc,
    You say above "You will need to supply 7.4 to 8.2 volts to these servos".
    Is that strictly true? Will the servos allow you to fly a perfectly serviceable plane at the stock Extreme Flight ESC BEC voltage of 6V?

    I am a complete beginner at 3D and precision flight. Will the 6V be "perfectly OK", and in fact "preferred" for a beginner? I am quite certain that I am NOT ready to deal with extreme plane "flips", like you most certainly are. I would think that I would like some maneuvers to be notably slower than yours!

    Also, you use extreme throws and the stock servo extensions. While learning, I would think that it would be better to reduce the mechanical advantage of the servos by using the stock arms, and utilize the holes closer to the servo pivot point. This way, the performance of this highly responsive plane could be learned with long servo throws and reasonable surface throws. Adjusting the arms during the life of the plane, or even just replacing them after gaining some experience seems like a reasonable additional investment.

    Thank you,

    1. "and the stock servo extensions" should probably have said "and the servo arm extensions"