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View Full Version : HDX300 (HB CP2 Conversion) Build Complete (almost) WHEW!!


Rhumba555
02-03-2007, 11:25 PM
Got the helicopter bug around Xmas and thought I'd just get a RTF and be done with it....HA! So I started with a HB CP2 (Blade CP) and flew it around a bit, crashed it a lot and spent a small fortune on replacement parts before learning that it really was a POS as far as quality helicopters go so I tried to upgrade it with a CNC head cuz the original plastic head was so sloppy I was having trouble hovering in the house. What started out as a minor upgrade turned into a full blown HDX300 Brushless seperates build. I don't know how the actual kit comes but I bought mine piece by piece over a few weeks. Here's the particulars:

Basically I followed Finless' videos:

HDX300 belt drive conversion
Microheli CNC "Blade" head
Plastic Tail setup (maybe metal in the future)
HDX300 Brushless motor/9 tooth pinion
Sonix 18A Brushless ESC
GWS 6 channel Reciever
Futaba T6XAS Transmitter (from my planks, doesn't work well)
Hitec HS55 servos all around (will upgrade the tail servo later)
HDX300 Blue main gear with autorotation bearing
HDX300 Landing gear (the wider flexible ones)
Carbon Fiber boom (recommended on this forum)
Stock symmetrical woodies and the stock tail blades that came with the tail system
Telebee HH gyro
Stock 3S 1000 Li-Po

I have built a lot of kits in my time, planes, cars, trucks, etc and I can tell you I have never had to modify, change, replace and find as many things on any kit as I had to on this build. To name a few:

Most of the links in the head were too tight, the links for everything else are too loose!

Tail servo mounts had sloppy threads, had to re-tap to 2-56

Had to order HB King servo linkages, no one told me that during the order process

Tail pitch slider would not slide on tail shaft, had to drill it out to make it smooth

No motor mount screws provided (odd metric size) Re-tapped motor for 4-40s.

Had to install the head servos upside down (output shaft at the bottom) because the HB King servo linkages were longer than the stock HB CP2's. This I found out AFTER I threadlocked them the other way! (Oh, and Locktite eats plastic)

Two holes on the top plate for servo mounts were sloppy, had to re-tap those to 2-56 also.

And the list goes on. Numerous other things that had to be fixed or modified. I finally got everything working and I'll tell you...HEAD SPEED! Man that brushless is awesome. However, I don't get liftoff until about 80% throttle and that is with about 8 degrees of pitch. when it does lift off it wobbles like a gyroscope, pivoting around as if it were hung by the head button, I still have some work to do with balancing and tracking and gyro adjustment and I know the radio is not helping me (it seems more designed for gas helis) but I'll get it eventually (hopefully). I will be upgrading the radio to a 7CHP someday.

Well, just thought I'd let you all know what I went through on this build. It was fun, challenging and totally frustrating at times. In retrospect, I should have just saved and gotten a Trex but I like this size of heli as it is small enough to fly in a basement. A Trex is definately next though.

Any tips would be appreciated and if you want photos just ask.

davidnichols
02-04-2007, 08:00 AM
wow that's a heck of a build process.

I am looking into getting a third helicopter (like you I got bitten bad by the bug at christmas, my brother and I got blade cx2s when I was in the USA for christmas), I just finished my T-REX 450SE build which was a great experience for me (I have no prior modelling experience), but I sure had to learn a lot fast (well I wanted to anyway :-) ).

I didn't have any help, as I live in Prague, Czech Republic and have not yet been able to meet any other fellow heli addicts here who speak english! So I built and configured the T-REX all by myself (well with finless' help in the form of videos - those were great).

Anyway it flies great, super stable and man it is an impressive machine. Still getting the hang of it; I ordered a simulator but it seems that the czech post lost it - been 3 weeks today since I ordered it, still hasn't arrived, so I'm doing all my learning by flying it in the garage of my apartment building :-) (here's a video of me hovering it for the first time: http://www.youtube.com/watch?v=ga-ClgsT3YM in the entrance hall to my girlfriend's apartment in Jihlava during a snowstorm :-) )

Anyway, I was thinking that it would be great to get a blade CP/CP Pro with a belt drive and all that jazz for flying indoors, and then I caught sight of the HDX300 that looked perfect - like a T-REX but the size of the blade. However I'm worried by some forum posts I've seen on a couple of sites (including your post) where people are saying that these machines are impossible to get stable.

When you say it's moving like a gyroscope, could that be that something is out of balance (could be blade weight or even pitch is too high/low on one of the main blades, etc) -meaning something you can fix, or rather a design issue with the kit?

I saw a couple of videos on the rchover.com site where it was flying, but it didn't look very impressive - just flew back and forth a bit and I never saw it in a stable hover that I can recall.

Good luck with that and keep us posted with your progress on getting it stablized!

David

Rhumba555
02-04-2007, 11:06 AM
At this point I'm pretty sure it is just final tweaking and balancing and setup. I'll let you know how it goes.

Buzzkill
03-20-2007, 10:08 AM
How did it work out? Does it fly well now? I've heard from a lot of sources (no offense) that the 300 sucks. I hope this isnt true. From what you've went through it should fly its self and fetch the morning paper lol. Anyway I hope everything worked out in the end.

Rhumba555
03-20-2007, 04:07 PM
It does fly well, as well as can be expected I guess. It's my first "quality" helicopter so I can't compare it to anything else but I can tell you this: It is not for those who need an instruction manual for assembly, it needs a lot of modifications to fly well and is not for the mechanically disinclined. The overall cost with non-top notch components is a selling point though. If I had it to do all over again I would simply have bought a Trex or a MX400.