Trex 250 Build Log

[Doozer]

Build thread is edited for the most part. I added links at the bottom. I didn't spend any time on the spell check so forgive the misspelling. I'll add videos as I fly it. Remember, if you buy this heli to buy spare parts with the heli. Skids especially.

[Doozer]

Feb 6, 2009 1:55:39 GMT -6 Solitaire said:

Thanks Doozer.

I wonder if those metal skids from XM would work on that l'il thing.

Bam! This just hit me like a bolt of lightning. I totally just buzzed right over it the fifteen times I've looked at this post. Good looking out. I'm going to try them. Do me a favor and post the link again. Or remind me where you posted it the first time. I'm sure even if the don't that its nothing a drill bit or a Dremel can't fix.

[Solitaire]

I guess I should learn not to ask too many questions while a fellow is in construction mode. ;D

These may be too large for the little guy...www.cnchelicopter.com/servlet/the-264/zoom-zap-shogun-3dx/Detail

[Doozer]

No, No, not to worry, I think they will. The zoom zap shogun series were all 200 class helis. For 9 bucks It's worth a shot. I may just have to buy a Hurricane 200 if they don't fit my 250. (how's that for rationalization). Very good call. Thanks for the link. I really didn't want to put oversize superskids on this. Those skids look sweet too.

[Doozer]

I got home and had an email waiting from Gary at Superskids, he said that he though they should fit. So I tried them and I think they'll work. While I'm still breaking this heli in anyway. Here's some pics and some install pics:


Skids are a touch long but for now that's added stability.


Add 250's to that now!!

Here's the install:




Hard to see in the second pic. However if you look hard enough, you can see that both screws are at the ends of the middle channel. Assuming that the ends are equidistant from the middle, the skids should be even on both sides and no measuring was needed. I had to use the long middle channel because the holes were too wide. Also I had to drive the head into the channel some in order to have the screws tight enough to hold... buttah! I used screws left over from the build. So I didn't have to do any extra drilling and if I want to put the original skids back on once I've figured this thing out, I can. Although I probably wont since they suck. I don't have scales... still, but its certainly light enough for how I'm flying right now.

[Doozer]

Here's a hover video with the Super Skids. One thing to note as well... the hub came unscrewed from the pitch slider. Always do preflight checks. The preflight check just saved this heli. I wasn't planning on using training wheels with hover so this problem could have been disastrous.

[beedm]

Robby, hi there. Listen, did I see where you were using the HT-55 servo's? Reason I'm asking is I've got 4 of them. Unfortunatly with the esky stuff and the belt...they work completely backwards and even reversing the xmtr switches helped...but then the cc was out of wack. Tried to rewire, but to no avail. How did you get those to work?

[Doozer]

Yep. In my HDX I use them, but I also use a different Radio and Receiver than the original RTF. In my radio, I can electronically reverse each servo. I use my throttle (pitch) to decide what individual servo needs to be reversed. Pic below:

You go into your radio's servo reversing to reverse each servo.

Now, once this is done, you may still have some reversing issues. So next I check the roll. In the case below, when I gave it some left or right cyclic, the servos operated opposite.

I had reverse the Aileron servo throws. Because I had already reversed my servos using pitch stick input, the only way to change the direction for a specific stick input is to do it numerically in the Swash Mix.

I'm not sure how you'd go about doing this with the Stock radio from ESKY. But that's how I deal with the problem.

[Solitaire]

I meant to post this earlier after watching your livingroom hover. The 250 looks pretty solid. Looks like it's small enough to navigate around the house. (hint, hint)

BTW, still anticipating the video for the piro contest. But, no pressure. ;D

[Doozer]

I have to stop crashing first. When I try to piro near my garage and out of the breeze I get very paranoid... of everything... I yell at my kids when they walk out the door. So I've come to the conclusion I need more space. So ... I've decided I'm buying a new house with more property....

I don't have it that bad, just kidding, but I do need to go somewhere where there is some room.

[Doozer]

Got two of these in the mail today www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6784 . If I like them I'll get more. I'll run them through a couple of flights then throw them on my watt meter. According to the reviews they work well. I hope so, because they were very inexpensive. I had to change my ESC and other battery over to deans though. A negative is the size of the wire that they use.... too big... anyway I'll keep everyone posted on this.

[akent]

Doozer, I'm also running the Zippy's on my Exi. The 2200 30C.

These are great batteries! These run nice and cool, and are very consistent. And you sure can't beat the price!

That 250 is VERY impressive!

Best,
Kent

[Doozer]

Thanks kent,
This little heli made me buy the Trex 600. Solid in every way...except the skids.

Well, I did a battery test. I kind of compared apples to oranges here, and my test wasn't all that scientific. I flew 3 battery packs in a row with a small break in between each one to allow the motor to cool down some. I first flew a Zippy 800 mah 20C, then an Outrage 800 mah 25C, then the other Zippy 800 mah 20C.

Zippy #1 - 9min 49sec. 5ft Hover. Steady Even power through the whole pack. Crisp response to cyclic. 1ft altitude loss with cyclic movement. Lukewarm to touch.

Outrage- 9min 33 sec. 5ft hover. Power fluctuation. I had to have my hand on the throttle the whole time. Cyclic input caused significant power loss resulting in a loss of altitude, and the skids to touch the floor. Warm to the touch

Zippy #2 - 9min 39sec. 5ft Hover. Steady power through entire battery. I was able to keep my hand off the throttle for half the pack. No left stick at all. Cyclic Input did result in a loss of 1ft of altitude, but I was able to retain altitude by reducing cyclic input. Warm to the touch

Things to note. The Outrage was a 25c, and the pack had 10 flights on it. The Zippy's were 20c and this was their first flight each.

The power was there in the Zips. Steady even power. Either the Outrage was not really 25C or the Zippy's where underrated. I don't have anything to measure RPM... I'd like to get one, but just eyeballin' it and listening, the RPMs looked to be close. Time will bear out whether the Outrage is worth the money. It's lighter, and the battery wires on the Zippy's are way to big. Overkill even. I'm going to do a little more testing, its a little early for me to say "Good Buy" but it's sure looking that way.

[Doozer]

I haven't added to this thread in a while. I've now flown this heli numerous times with only a little tightening here and there. The stock skids are back on. I do need to adjust the pitch curves again because i changed the servos throw a little. What a nice flying little heli. Best flier I have. I can do stationary, slow 180⁰piros with not much input from the cyclic. Stick to heli translation is almost instantaneous. This is a good buy. If you've flown any of the fixed pitch sub micros (Walkera 4#3 ish) This is an easy heli to fly... stable as hell.

If you're looking to step up from sub micros to micros, this is a nice step.