Mini Heli Blog

Getting More Comfortable with Rolls

I’m pretty confident in doing rolls now. They’re still a bit sloppy, but I think I need to increase my pitch/aileron swash mix a bit, and I’d like to upgrade the motor. When flying the Trex 450 in the RealFlight simulator, my rolls are all really clean and tight, and I think it’s because the sim uses the 450XL 3550 Kv motor, while my actual helicopter uses the 450L 3150 Kv. I think I also just have more confidence in the sim since if I crash, it doesn’t cost me anything.

Another modification that I’ve made that may tighten up my rolls that I’ve yet to test is in reprogramming my Align RCE BL35G ESC. This ESC came with my 450SA kit, but I never found any instructions on how to program it until recently. It is the newer “G” model, and unlike the older ESC versions, has 5 programming options. I realized that my 5th option which controls the throttle response speed was set to “Low” (1 beep), and have since changed it to “High” (3 beeps).

You can find the manual for the Align RCE-BL25G and RCE-BL35G here:
http://www.align.com.tw/html/en/c_rindexe.htm

It’s been really windy here lately so I haven’t taken it up in a while. Here is me doing some rolls from a few weeks ago though (forgive my retarded commentary):

Commercial Uses for Lithium Batteries

funny xkcd comic:

Installed the CopterX Head, Did my First Roll!

As mentioned in my previous post, I totaled the stock, plastic SA head attempting a roll. In hindsight, there were a lot of problems with my last attempt. I had the flybar weights on, and my swashplate settings weren’t set right. My pitch was also set up improperly, and when I went inverted, I didn’t have enough power to pull me through the roll.

Instead of trying to rebuild the plastic head, I ordered the CopterX head from ebay for $40 shipped, and it’s beautiful. No vibrations and very stable flight. I really can’t see any difference between this and the Align head that costs 3x as much. Hopefully my next crash won’t be as bad since I now have a metal head, but if I ever total it again, $40 isn’t too bad for a quick fix.

Today I tried the roll again, this time with the aforementioned adjustments, and I pulled it off! It wasn’t pretty and I was nervous, but I did it. My wife only got the first one on tape, the second one looked a little better, and hopefully tomorrow I can give it a few more shots. It really is a lot like the Realflight simulator so in the mean time I’ll keep practicing on my computer.

Trashed my TREX 450 Plastic Head and Ordered a Metal CopterX Head from China

A couple of weeks ago I had my first huge crash in my TREX 450. It’s a shame I don’t have it on film, since the crash was so spectacular. I was attempting a role too close to the ground, and the bird met tera firma blade first almost completely inverted. Damage to the head was total. The SA has a mostly plastic head and therefore I broke mostly every piece of it. Since I was in stunt mode, the gear was chewed up pretty badly since it took me a second to kill the motor. The main shaft was bent at almost a 100 degree angle. Amazingly the wooden blades were just fine, since the bladegrips and the rest of the head took all the impact I guess.

I priced out replacing the pieces for the head, and decided to just replace it with a full metal CopterX head. The one I ordered was only $40 shipped from China, and reading reviews on helifreak.com it seems that it’s almost as good as the Align setup (at a fraction of the cost). Having ordered R/C stuff from China in the past, I know that it can take up to 20 days to receive it, but I need that time to fly no the simulator and get this last crash out of my system. I’m also going to spend a lot of time making sure that my head is setup perfectly this time. helifreak.com has great videos by “finless bob” that show the proper way to set up the collective and pitch of the head. My SA came fully assembled, so I pretty much just put in the servos and started flying. Looking back, it seems that if I had had more negative pitch available during my role that I would have been able to pull it off. Although I really have no idea where it was.

Once I get my new head on and setup, I’ll write up a review of the CopterX head compared to my plastic Align head. I’ll also be sure to catch my next roll attempt on video.

Hitec HS-65 Servo Way Better than E-Flite S75

One of the weakest points of my TREX 450 SA build was the cheap E-Flite S75 servos I used for the cyclic. They had trouble centering and just didn’t have much torque and it seemed I was always adjusting the trim to get a good hover. This weekend, I tossed them in favor of the Hitec RCD HS-65 servos which seem to be the defacto servo for the TREX 450… It’s seriously night and day. The HS-65’s center very well and move the cyclic with authority. They also take full-sized servo horns even though these are micro servos. Here’s a picture of the two next to each other:

The new version of the HS-65 has 3 holes (instead of the previous 2, requiring you to drill a center hold for the TREX), so its a direct fit. If you’re going to pick these up, be sure you’re getting the new 3-hole version.

My First Crash with the Align TREX 450

So it was bound to happen sooner or later. I hadn’t been doing any flying for the last couple of weeks with my TREX 450 (or any helicopter since I got rid of the Axe CPv3), but on Saturday morning, since it was the first day it hadn’t rained in a while, I went to a local park with my wife to hover around. I affixed some training gear to the landing struts just to be sure I wouldn’t tip on the uneven ground in a landing, but I ended up crashing it anyway.

I’m not exactly sure what happened, but it seems that my elevator servo in the collective failed and that’s why I lost control and landed on my side. It actually wasn’t too bad of a hit, as both blades flew off (breaking at the blade grip), and the landing gear struts snapped off. The elevator servo is also ruined, but I think that was what failed, although it might have been something else and the servo could have just died in the crash.

In either case, I’m getting rid of these jenky E-Flite S75 servos that I have. They have a terrible time centering, and just seem really weak. I’m contemplating between the JR Digital 285 or the Hitec HS65 servos. The JR digital servos obviously will do a better job at centering and keeping their position, but they’re relatively weak and slow (and expensive at $35 each). The HS-65 servos seem to be the most commonly used servo in the TREX 450, with a decent speed, the most torque in a micro servo, karbonite (or metal) gears, and a ball bearing on the top. I originally had thought about the HS-65 servo, but it seemed that the mounting holes wouldn’t line up and I would have to drill custom holes for them. Well the new version of the HS-65 has 3 mounting holes, so they fit fine in the 450 without any modifications. I found the karbonite gear version on ebay for only $21 each, so I think I’ll pick them up and try them out. I’ll write up a post about them once I get them in and fly them around.

Before the crash, my wife took a minute of digital video on my new Sony MHS-CM1 HD camera that I just got. The video isn’t very interesting, I’m just hovering around before I start flying (and crashing which isn’t on the video).

Cheap LiPo Batteries on eBay

I was pretty skeptical about some of these really cheap LiPo batteries available on eBay that ship directly from China, but so far I’ve been very pleased. the 11.1v 25c 2200mah batteries that I use for my T-Rex 450 are about $75 at local hobbly shops and online, but the same battery can be had for about $20 (shipped) from eBay sellers shipping directly from overseas.

So far I’ve had no problems with charging or output or consistency with these batteries. It makes sense that manufacturers in China can sell for much less since these are likely the same batteries that get re-branded and redistributed here in the U.S. Just thought I’d share that insight, and if anyone has had bad experiences with these cheap LiPo’s, I’d be interested in hearing your thoughts.

Well, I think I’m Done with the Axe CP

I know I didn’t have too many posts on this blog about the Axe CP, and it looks like I won’t be saying much more about it at this point. I think the Axe CP was a really good helicopter to learn hovering in all orientations and forward flight and flying circuits. It was cheap enough to get into the hobby, and now has me hooked. The problem is that it’s just so small and fragile, and the replacement parts are too expensive.

A couple of weeks ago I had a pretty bad crash, losing orientation about 25 feet up and coming down on the rotor head. $50 worth of parts ordered from Tower Hobbies later, and I still had some pretty bad wobble, and as I was making adjustments, I broke a ball off of the swash plate and kinda decided that was enough (having just installed that swash plate). If it had a metal head, I’d have more interest, but setting up the metal head on the Axe CPv3 is gonna be a few hundred dollars and that’s just kinda nuts.

So it looks like I’m going to focus all of my attention and flying on the T-Rex 450. It’s the helicopter that I probably should have bought in the first place, but the initial investment is so steep, that I didn’t want to spend that much money if I ended up bored with it. It’s also nice that I didn’t have all of those crashes that I did with the Axe on the T-Rex, so it’s still in nice shape (although I’m sure that’ll change once I start trying 3D on it).

Back to the Simulator

Most people these days will tell you to spend your first $200 on a simulator instead of a real helicopter to learn how to fly. As true as this might be, I was much more interested in buying the real thing and just paying the price in replacement parts. In hindsight, which is always 20/20, I would have saved a lot of money had I done the simulator first, but it definitely wouldn’t've been as much fun. Now that I can hover in all right-side-up orientations and fly simple circuits with confidence, I’ve decided to go the simulator route to learn the next level of flying.

Learning to hover and do forward flight isn’t too difficult, particularly if you use training gear and keep most of your flying only a few feet off the ground, even the worst crash from that height isn’t going to be too pricey. The other day, I lost orientation in my Axe CPv3 at about 30ft, and I broke/bent just about everything in the rotor head. So about $50 worth of ordered parts later and I decided to start flying in RealFlight G4 to learn more advanced maneuvers and start practicing some simple 3D. G4 comes with the Axe CP, and the T-Rex 450 is available as a download from the Knife Edge website. The physics of both helicopters seem to be pretty accurate so far, and virtually wrecking the T-Rex is a lot less disheartening than the real thing. I do however try to treat each flight as if hundreds of dollars were riding on it, and have only had a few disastrous crashes.

Once I get my replacement parts for the CPv3, I’m going to try some simple rolls and flips on the real thing that I’ve perfected in the simulator. I usually try to fly with a bit of wind on the simulator too just to be prepared for what it actually is like. I also can’t seem to keep the helicopter very stable hovering inverted. I can usually keep it inverted long enough to figure out the orientation, but since 2/3 of the controls are always reversed, I haven’t been able to do it naturally like I can hovering nose-in/tail-in (right-side up). I’ll be sure to film it when I try it with the real thing. I’m sure it’ll make for a fantastic crash

Great Customer and Warranty Service from Heli-Max

I often complain about how much replacement parts for the Axe CPv3 cost, which usually break because of a crash that I caused. However a few weeks ago, I plugged in my battery and a few seconds later the blades started spinning at full speed, as if the 3D switch was on, but it wasn’t. I quickly unplugged it, but not before the blades struck my knuckles and the ground as I was trying to handle it. After that, I tried plugging it in again without the main motor leads connected and I got no lights, nothing, and smoke started coming out from one of the servos.

So I sent the servo, 3-in-1 board and the blades (which had been flawless before this incident) to Heli-max with the explanation and today I received the brand new replacement parts, no charge. Anyway, great customer service like this is what makes me a fan of a brand for a lifetime and I’m happy to recommend Heli-max products to my friends.

Hats off to you Heli-max.