SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jan 22, 2010, 10:42 AM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
I saw the HK250GT says it has counterballanced tail rotor grips (chinese weight mod).
Anyone can comment on this?
Melnic is offline Find More Posts by Melnic
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 22, 2010, 10:57 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Mel -

I honestly can't see that, but the pitch slider does move very smoothly along the tail shaft with little force at full RPM, so perhaps the tail rotor grips are a bit heavier to add some counterbalance.
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Jan 22, 2010, 12:46 PM
Registered User
markh78's Avatar
Saitama, Japan
Joined Aug 2009
154 Posts
Damn, I totally forgot about one important rule on heli maintenance: never do it when you're drunk
I managed to try to connect the lipo the wrong way, quick buzz and puff, there goes my esc
Ah well, quick trip to HK for a Turnigy amp...
markh78 is offline Find More Posts by markh78
Reply With Quote
Old Jan 22, 2010, 02:19 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Swapped out the stock feathering shaft for the Align part, the stock feathering shaft was not that bad, it was loctited in quite well, and it took quite a bit of force (using pliers) to bend and break it. It's no Align feathering shaft, but it probably would've sufficed until the first crash. Perhaps HK is using better-quality feathering shafts, I'm not sure, but it was not all that easy to bend it. I'm generally not terribly concerned using softer metal parts because they give out first in a crash, preventing damage to other components.
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Jan 22, 2010, 02:22 PM
I Can Fly An FP Inverted!
Hal_The_Hacker's Avatar
Teddington, Middlesex, UK
Joined Jun 2008
1,536 Posts
no seriously, the stock feathering shafts, wont hold up to high headspeeds. they will just strip out.....not good.

the park HPX-F servo is heavy, slow and inaccurate for a 250, as is the 401b, but both will 'do the job' i guess.

and the stock mainshaft is okay, it will bend in the first crash, but will last just fine till then.
Hal_The_Hacker is offline Find More Posts by Hal_The_Hacker
Reply With Quote
Old Jan 22, 2010, 02:35 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Hal -

Do you have any suggestions on a small, faster tail servo (at about the same price as the HPX-F, ~$12 USD)? I wouldn't mind replacing the HPX-F, but it's not all that slow, 0.05sec/60 @ 6V(which is what I run off of my external UBEC), it has a lot of torque as well (3.6kg).
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Jan 22, 2010, 03:33 PM
Registered User
Evan D's Avatar
Charlotte, NC
Joined Jan 2004
6,181 Posts
Keep the stock feathering shaft in, it's a cool crash. I was zipping along in FAST forward flight and both main blades departed.... very cool, I laughed so hard. The replacement parts are so cheap it was not a big deal at all.

As far as canopys, the other 250 canopys that Hobby King sells come much nicer than the GT canopy, no warping and a better finish.

Quote:
Originally Posted by rcnewb View Post
So I read earlier in the thread that the stock feathering shaft is an explosion waiting to happen (250GT). Can someone confirm whether or not this is really the case? I've spun up to full RPM (Scorpion 2206-3900Kv motor, 14T, 3S 1000mAh 15C LiPo pack) and it tracks/spins smoothly with virtually no vibration (I didn't even have to adjust the blade tracking, set my linkages as per the T-Rex 250 manual and all is well).

One thing I've noticed is that at full negative, with cyclic forward, the HXT900 servo arm (the lower servo on the front) nearly touches the main gear, I've sanded it down quite a bit to eliminate the issue, but it's still very close. I found that if the servo arms weren't SLIGHTLY down at neutral, that there would be too much positive pitch (to the point of binding) and not enough negative, I like to set heli's up for equal -/+ pitch. Also had to use quite a bit of subtrim on 2 out of 3 of the cyclic servos.

My only gripe with the 250GT is the canopy, the one side seems warped and there is not enough room for my 3S 1000mAh 15C LiPo (Zippy) pack inside the canopy. Still need to tidy up wiring as I used an external BEC for the Rx/servos, which means a few extra wires to bundle up. Is anyone else using the 3S 15C 1000mAh Zippy's? Any advice on how to fit the d@mn thing within the stock canopy?
Evan D is offline Find More Posts by Evan D
Reply With Quote
Old Jan 22, 2010, 03:37 PM
Registered User
UK
Joined May 2007
3,204 Posts
Quote:
Originally Posted by rcnewb View Post
Since I have the Align 250 feathering shaft, I'll go ahead and replace the cheesy stock shaft. However, I can't imagine the stock shaft bending unless it was in a crash. Are they bending spontaneously during normal flying conditions? That seems really bizarre IMO.
Read the beginning of the thread. I didn't even bother to put the original feathering shaft. It is dangerous!
clicky is offline Find More Posts by clicky
Reply With Quote
Old Jan 22, 2010, 04:02 PM
I Can Fly An FP Inverted!
Hal_The_Hacker's Avatar
Teddington, Middlesex, UK
Joined Jun 2008
1,536 Posts
Quote:
Originally Posted by Evan D View Post
Keep the stock feathering shaft in, it's a cool crash. I was zipping along in FAST forward flight and both main blades departed.... very cool, I laughed so hard. The replacement parts are so cheap it was not a big deal at all.

As far as canopys, the other 250 canopys that Hobby King sells come much nicer than the GT canopy, no warping and a better finish.
you wouldnt be laughing if you were minus a lung due to the incident....
Hal_The_Hacker is offline Find More Posts by Hal_The_Hacker
Reply With Quote
Old Jan 22, 2010, 11:28 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Well, I see the issue with the tail slider - it binds when it travels too far to the left (as you're facing the TAIL end), I'm already using the first hole on the servo arm and even if I dial down the travel rate on the Gyro to 20%, it seems to move too far across the tail shaft (in both directions).

Head speed seems really fast when throttling up above the 80% range, all sorts of strange behavior from the tail when the head speed increases at higher throttle %'s. I think the tail blades are flexing at high RPM's, something is making them go off track and they are being driven to the left end of the tail slider (causing binding), it's odd because they track flawlessly at lower RPMs, razor sharp. I'm not using the stock tail blades, I'm using these from helidirect. Any ideas on this one?
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Jan 22, 2010, 11:37 PM
Team Wack-a-Mole
Melnic's Avatar
Maryland
Joined Oct 2008
8,439 Posts
rcnewb,
I cover the tail in my EXI 250 review (same heli as HK250GT)
http://www.mycoolheli.com/reviews/ReviewEXI250.html

Move the ball on the servo as far in as you can, especially with the stock tail control arm.
Melnic is offline Find More Posts by Melnic
Reply With Quote
Old Jan 23, 2010, 09:07 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Anyone have experience with the microheli precision tail set? It's pricey, but I use something similar on my 450 (CNC metal tail from xmseller) and it makes a huge difference in terms of tail performance. The stock tail assembly is weak and does not seem like it will hold up at higher head speeds, IMO.
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Jan 26, 2010, 08:56 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Even though no one responded to my query, I went ahead and ordered the microheli precision tail for the 250GT, installed it, and flew on it the other day - wow what a difference it makes having an all-metal precision tail (I use the xmseller V3 CNC precision tail on my HK-450, and it was worth its weight in gold). I can piro the hell out of the 250GT and it stops on a dime, on command, every time with no bounce, wag, or any other type of erratic behavior. BIG difference from the stock tail assembly which had a lot of slop and would bind on the left side (toward the tail boom) if it moved just a hair too far, IMO the 250GT was not fly'able on the stock tail pitch slider.

Here are the electronics I'm using...

ESC: Castle Creations Phoenix 35-Amp
Motor: Scorpion 2206-3900Kv
Pinion: Scorpion 14T
Cyclic Servos: HXT900
Tail Servo: GWS Park HPX-f @ 6V (0.05sec/60 @ 3.6kg of torque)
Gyro: HK 401B
Battery: Zippy 3S 15C 1000mAh

Only real complaint was the stock canopy, it was too small, wouldn't fit the battery, so I ditched it for a larger Fusuno canopy. The 250GT behaved erratically on the stock tail assembly, it felt mushy (even with Gyro sensitivity dialed up), and would occasionally bog down the head due to rubbing/binding on one side of the tail or the other.

Upgraded parts (replaced up-front)
Align belt, Align feathering shaft, Align 205D Carbon Fiber Blades, Align white tail blades
ChrisWNY is offline Find More Posts by ChrisWNY
Last edited by ChrisWNY; Jan 26, 2010 at 10:06 AM.
Reply With Quote
Old Jan 26, 2010, 09:54 AM
Registered User
UK
Joined May 2007
3,204 Posts
Quote:
Originally Posted by rcnewb View Post
Even though no one responded to my query, I went ahead and ordered the microheli precision tail for the 250GT, installed it, and flew on it the other day - wow what a difference it makes having an all-metal precision tail (I use the xmseller V3 CNC precision tail on my HK-450, and it was worth its weight in gold). I can piro the hell out of the 250GT and it stops on a dime, on command, every time with no bounce, wag, or any other type of erratic behavior. BIG difference from the stock tail assembly which had a lot of slop and would bind on the left side (toward the tail boom) if it moved just a hair too far, IMO the 250GT was not fly'able on the stock tail pitch slider.
I've ordered one too... (good find, thanks!) I've started with original tail slider then swapped to Align's and then even bought rest of the align parts for the tail and they turned out to be with more slop than original HK parts (not the tail slider though).

Whatever I've been doing it would always ends up having a bounce (all with Gy401). After GWS Park HPX-f and s9650 I finally settled with Ino Lab's 201 BB servo. It holds, it is flyable but stationary roll test shows that tails is not quite there yet (it finishes the roll with tail 20-ish degrees down).

Quote:
Originally Posted by rcnewb View Post
Here are the electronics I'm using...

ESC: Castle Creations Phoenix 35-Amp
Motor: Scorpion 2206-3900Kv
Pinion: Scorpion 14T
Cyclic Servos: HXT900
Tail Servo: GWS Park HPX-f @ 6V (0.05sec/60 @ 3.6kg of torque)
Gyro: HK 401B
Battery: Zippy 3S 15C 1000mAh

Only real complaint was the stock canopy, it was too small, wouldn't fit the battery, so I ditched it for a larger Fusuno canopy. The 250GT behaved erratically on the stock tail assembly, it felt mushy (even with Gyro sensitivity dialed up), and would occasionally bog down the head to to rubbing/binding on one side of the tail or the other.
Did you get to fly it with Turnigy 2627 motor to compare it? With this one with 15T(haven't bought 13 and 14 yet) at roughly 85% throttle it is quite powerful!

Quote:
Originally Posted by rcnewb View Post
Upgraded parts (replaced up-front)
Align belt, Align feathering shaft, Align 205D Carbon Fiber Blades, Align white tail blades
Similar here: super tail belt with kevlar fiber, align's feathering shaft, align's tail slider, Align's yellow tail blades. Main carbon blades are next on the list
clicky is offline Find More Posts by clicky
Reply With Quote
Old Jan 28, 2010, 08:14 PM
Registered User
Pepelatz's Avatar
Staten Island, NY, USA
Joined Aug 2006
285 Posts
Gyro choice

I'm starting my first heli build (had only RTF 4g3 before) and have a question:
I have 2 gyros already: HK 401B and Turnigy (Telebee) GR302-AD. Out of these 2 gyros which one you'd put on 250GT with MKS DS480 servo?
Thanks,
Ro
Pepelatz is offline Find More Posts by Pepelatz
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Nitroplanes Lander 70mm F9F Panther EDF Build Log and Review The Don Foamy EDFs 38 Jun 03, 2014 11:09 PM
Discussion Official HeliMax AXE CP Thread with pics post em here!!?.. darklyte24 Micro Helis 10603 Mar 27, 2014 07:49 PM
GWS Spitfire Build thread (with glassing tutorial) David Winter GWS (Grand Wing Servo) 156 Sep 14, 2009 06:42 AM
Discussion Build log or review for BulleT? raycsr Electric Sailplanes 3 Jan 30, 2009 02:03 PM
looking for build thread with upclose photos HIGHFLYER99 Foamies (Kits) 13 May 21, 2005 09:54 PM