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Tuesday, March 17, 2015

60" Laser__Worth The Wait

Now it can be said: I waited too long to get a 60" Laser. I planned to build one all along, but other things kept getting in the way. Mostly it was a matter of funding and priorities. Just when it seemed like I would never get around to it, Hitec sent me some badass HS7245MH servos and made the project possible. So, here's a big thank you to my friends at Hitec.

De LaMoose
As chronicled in 60" Laser EXP__Finally, this is one moose of an airplane. It's just massive and immense in every sense of the word. For example, I transport all of my 60" EXPs across the back seat of my car, and that's with the rudder cocked so I can get the door shut. With the big Laser, this is not even an option because the thing is so much longer. I had to stand it up in the front seat, and even at that the rudder was only about an inch from the headliner. When I set it down next to the 48, it looks a hell of a lot larger than an extra foot of wingspan. This is such a big plane I almost titled the article "Laser EXP__Immense"!

Light Weight Flying Nature
This plays itself out nicely in the air in the form of more lift producing area. When you have the wing stalled in 3D flight, you have to fight and scratch for lift anywhere you can get it, and a big fuselage, canopy, cowl and monster SFGs really help here. Each new EXP seems to get a larger and larger fuselage, so you can see the evolution taking place.

The Laser rivals the Edge and Yak for being light on it's wings, and this gives it dead solid harrier manners. In fact, I almost group these three together as the same plane because they are so much alike in this respect. This light flying nature has sort of won me over and I am starting to prefer these 60" EXPs over my beloved 48s. Pragmatism keeps the 48s in the game, but outside of that, the 60" EXPs simply rule. If I had a big car, more money and plenty of storage space, all I would have would be 60" (and maybe even larger) EXPs. These 60" planes are simply another world of awesome.

Instant Gratification
Much like with the 60" Yak, my initial reaction when flying a Laser was "Come on. It can't be this good." I had flown a friend's Laser once and was sort of ready for it, but even now I am still not quite believing how solid this plane is. It's nice when you like a plane absolutely right away.

My confidence was off the scale once I checked my trims and landed to turn my trim sensitivity down (from 4 to 1). Then, at the lowest trim setting, it took a single notch of up trim and that was it. That's the equivalent of 1/4 of a click of trim! This is the straightest plane I have ever built, but then again, it nearly came out of the box this way.

Smooth, solid and reassuring, the big Laser was sending me all the right signals right from the start. I sort of knew what to expect from flying my friend's laser, and from experiencing the Yak's eerie stability. Initially I wanted to be careful because it was seemingly too easy. That's when you usually get bit, but like with the Yak, it is that easy.

Spoileron Note
Lately I have been experimenting with a 25% spoileron mix on my 48" Laser, and I tried it on the big one too. However, I wanted the initial 60" Laser videos to be strictly about the plane, so for the videos in the articles I switched them off. We are planning to do a spoileron article soon, so stay tuned.

The big surprise was how fast this plane is. With all that fuselage area and corresponding drag, I figured the laser would be about the same speed as the Yak. Instead, the Laser seems to be about the same top speed as the Extra and MXS. It might have a lot of area, but it is a slick design.

Of course, this is certainly helped by using the torque 4016/500 motor. With a Xoar 16/7 wood propeller, I am getting close to 1900 watts. This equates out to 2.5469168901 horsepower (electrical)! Part of this is from the Torque being a badass motor, and the rest is from using Thunder Power 6s 3300 70C Pro Power batteries. These are not even the latest generation of TP packs, but they are still very potent.

 Speed always makes for better precision moves, and the Laser excels here, nearly to the point that it is as good as the Extra EXP. Much like the Extra, the Laser feels like it is locked into a big groove, or riding on a rail in the sky. A lot of this is due to the servos centering extremely well, but the big fuselage and flying surfaces make the plane want to plow straight ahead when at high speed. This is extremely useful for precision moves, and it takes a bunch of work load off the pilot when he is not having to correct the plane's path all the time.

Slow and point rolls are easy because the big fuselage provides a lot of side lift and the plane does not drop that much. For consecutive rolls, on low rate you peg the ailerons over and it's a simple sequence of tiny up and down inputs to keep her level and on track. Of course you have to have your low rate set up for that, and at full deflection I set the low rate up to give me three rolls in five seconds. This is only a few percentage points off what's in the manual, so your best bet is to always start there.

The precision game with this plane is very tight. It only gives up a little here to the Extra because with all the side area a strong crosswind effects it a bit more. This doesn't mean wind bothers the Laser much. It is actually quite solid in high winds, but the Extra flies a little heavier and thus penetrates better. I did my maiden in 10-15mph winds and it was absolutely no problem. In calm air the Laser stays right where you put it, though that's a bit of a rarity for me since I live on a peninsula.

 The Alpha Dog
Post stall provided a few surprises as well. Harrier flying with this plane is totally effortless. Most people agree that the Edge EXP is the king of harrier flight, but if the Laser gives up anything here I am not seeing it. Along the same lines, the Laser does a really sweet elevator drop maneuver, every bit as good as the Edge. With a 25% spoileron mix, it's just sick and almost unbelievable. When you see it on the video you are going to think I faked it somehow, but it's very definitely for real. I don't want to talk about the spoileron mix too much just yet because I am planning an article on it, but it's definitely worth trying.

Another nice surprise is that the Laser is the most solidly hovering plane I have ever flown. My hovers need to be better, but with the Laser they almost look really good. The first time I popped it up for a hover it was like "Are you kidding me?" Normally I don't even get around to trying a hover for a few flights on a new plane, but the harrier was so solid I just sort of pulled the nose up until she stopped and hung there. Very surprising, and most pleasing. I didn't even have to hold that much reverse aileron to counter motor torque, and when I run out of aileron control is when I usually bail.

Eerie Stability
Looking back on my initial flight with the 60" Yak, I cut the maiden short because I thought something was wrong with the plane. It was too easy, too solid and too locked in. I landed because I thought I didn't dial in enough throw or had too much expo ...... or something. It just didn't seem right. When I could not find anything wrong I just kept flying it until I realized the plane is so solid and stable that it had fooled me. In essence, it was too good to be true, and the harder I flew the plane the more it revealed how good it is.

Eerie stability. That's what the Yak has, and it sort of prepared me for what to expect from the laser. It was not such a shock because I was a little better prepared for it, but the Laser is still so smooth and surefooted that I ended the first few flights feeling like I left a lot on the table and could have flown it a lot harder. Now that we have the initial report finished, that's exactly the plan .... fly harder.

This is the big thing with the Laser for me. I was confident with it almost instantly. Once I got it fine trimmed it was like any other plane that I had a lot of time with. I knew exactly what I had and what I could get away with, and this was only a minute or so into the maiden. I would try different moves and it would do exactly what I expected from it. In a lot of ways it is much like the 60" Extra, though lighter flying. Since the Extra is the standard by which I judge every plane, any comparison to it is definitely a compliment. After a bit of time the 48" Laser became almost interchangeable with my 48" Extras, at least in the amount of confidence and comfort I had flying them. It is still a little early with the 60" Laser, but I am sure before long it will be the same thing with this plane.

The nicest thing about the Laser for me is that it has a precision nature of the Extra and the float-like-a-bee nature of the Yak. Right now it seems a little bit too easy, but that usually goes away when you start pushing the plane harder and harder. What the Laser has done is simply move the limit a little higher.

More On The  Hitec7245MH
This is my second set of Hitec HS7245MH servos and I am really pretty thrilled with them. I have been flying HS5245MGs on all my 60" planes right up until my newest Extra and was very pleased with those as well, but the 7245MH are in another league.

I now realize I was getting a little stalling with the 5245MGs at high speed because now am running less throw on my low aileron rates. I set that rate for three rolls in five seconds, which is about 27% of full throw. With the Extra and Laser I had to turn that down to 20% to get the same roll rate, so clearly the 5245s were a little overworked. Still, if they were stalling like that it is amazing I got nearly three years out of a set of them.

The higher torque of the 7245s show up best in high speed and high violence maneuvers. Walls and parachutes are completely different now in that they happen instantly. Tumbles are much more forceful because the servo moves so quickly, and when you demand it, to the extreme. There is no pause and no delay. When you ask something from these servos you get it right now.

Initially I was running these servos at 8.0 volts in my Extra EXP, but they were so fast that the plane seemed a little twitchy at high speed. I dialed that back to 7.4 and now they feel about right. I started the Laser out on 7.4 volts and am really happy with it like that. I have also done this with the Extra my 48" planes that are running Hitec HV servos. Since there is no hint of stalling and blowback, it is probably not necessary to push the servos any harder than that anyway. They are crazy fast on 7.4 anyway, so I am not giving up anything there either.

For precision work, a servo that centers better gives you a more precise flying plane. If the plane is climbing or diving when you go to start a slow roll, for example, now you have to do the maneuver and correct for a poor entry, which more than doubles your work. You end up chasing the plane through the entire maneuver and after two or three of those I am just too worn out enjoy the rest of the flight. It's too frustrating to have the plane do something other than you are telling it to do, but  good centering servos and a well trimmed airframe pretty much takes care of that.

When the plane starts off and says trimmed, that means it goes and stays where you put it, which makes nice precision maneuvers easy work, and the 7245MH are a definite improvement here. If these is any one reason these servos are worth it, this is it.

For post stall 3D flight, it seems about the same outside of the 7245's better centering. Super precise centering doesn't come into play as much in alpha because you are rarely at center and always making a correction or movement of some kind. Still, if the plane wanders off somewhere you are not telling it to go, that just makes the pilot's job even harder.  Even when centering is not at it's most critical, having the plane stay trimmed makes the plane do the work for you, and makes it easier for the pilot to put the plane where he wants it to go.

When the airplane is stalled or partially stalled and flying in alpha, you are not asking that much from the servos. It is only when you get into the high speeds with lots of airflow going over the controls that lots of torque becomes critical.

The big difference with the 7245MHs is that the plane flies better all the way around. These are expensive servos, but only because they are worth it. A set of 7245MH costs about the same as the entire airframe, but if you want to get the most out of it, you've got to have them.

We are not playing around any more. The Laser is a serious plane,  in a fun sort of way, that is. It deserves the best servos you can jam in it and these are it.

Not Quite The Last Gasp For the 5245MG
None of this means that the 5245MGs are now inadequate. They just are not as good as the best. For sport flying and sport 3D, they perform well, and reliably too. It is only in inch perfect precision and white knuckle extreme aerobatic flying that they begin to suffer a little.

I still have sets of 5245MGs in my 60" Edge and Yak, and those will probably remain there because they are paid for and working well. Of course, I am so pleased with the 7245s that I can't see spending the money on anything else. Spending more hurts, but only until you get them in the air.

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