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Old Jun 17, 2010, 02:04 PM
Excellence is Expected
MakMov's Avatar
Aurora, Colorado
Joined Nov 2005
3,736 Posts
Quote:
Originally Posted by chipbutty View Post
Well, you've managed more battery packs than me outside! Well, inside I've probably put 40 packs through it in an attempt to tame the tail.

It can take a leap of faith to go nose in with bigger helis. You'll be fine if you can do it with the 4/3B. On my brief flight with the 250 I was shocked at how squirelly it felt. It didn't seem to handle the slightest bit of wind well at all. But that could well be because of all the little issues I've been having with the tail. This little thing is and absolute pain to setup well. Bigger helis are much less sensitive.

I'll gradually upgrade with Align bits like yourself and I can see a better gyro will be needed. Quite fancy the Spartan but if I see a GP750 going cheap I'll pick one up. At the moment fancy stuff isn't neccessary for me - a nice gentle flight would be a good start

Not good about the Align tail shaft not fitting. These HK tail shafts scare me!

A good gyro will actually make it easier to fly.

You just have to change out the box so you can use Align shafts.
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Old Jun 17, 2010, 02:12 PM
Registered User
Sunny Sheff, UK
Joined Jul 2008
148 Posts
Thanks for clarifying MakMov.

Oh yes, I agree, a decent gyro will make things better. I was just being sarcastic as I would see a simple circuit as progress with this clone considering all the issues I've had.
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Old Jun 18, 2010, 05:58 AM
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Add1ct3dd's Avatar
United Kingdom, England, Worcester
Joined May 2010
682 Posts
align-trex.co.uk is where i got my gyro from,
i managed to get the gp750, ds420 and the align gyro mount with 2 foams and aluminium plate for 111 shipped, so not too bad!
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Old Jun 19, 2010, 01:46 AM
Low rates are for wimps
bwoollia's Avatar
United States, CO, Colorado Springs
Joined May 2008
3,309 Posts
Just flew my 250GT for the first time today. Here's the setup:

HXT900 cyclic servos
HK G401B gyro
Turnigy (MKS) DS480 tail servo
2627 4200kv motor
12t pinion
Turnigy Plus 18A

Align replacements: Main shaft, feathering shaft, belt, main gear with autorotation bearing.

Wow, what a heli! I'm amazed at the power of the little motor, I didn't notice much bogging at all. I really expected the collective to be very sluggish, it's just the opposite.

The tail holds very well. I'm using the stock tail rotor setup. It's very sloppy on the ground, but it's all loctited and I guess at the many G forces pulling the rotor blades out everything tightens up. A little bounce at either end, but for the most part it holds very well. Maybe a little drift, not much if at all.

There is very little vibration. I should be turning over 4000rpm but it's still very quiet. From some of the earlier posts I expected some howling and vibrations, but it was no big deal.

The cyclic interactions are terrible, but that's my fault. I need to do a better job of leveling everything. I broke a ball link and replaced a whole linkage with something from another heli, but it's not quite long enough so I had to use quite a bit of trim to get it to hover well, needless to say once I started moving the stick around weird things happen. However the model flips and loops very well, the nose tracking very nicely. I'm going to order an Align set of cyclic linkages and measure them a bit more carefully.

Any thoughts on leveling the servo arms? Because the servos are angled, it's hard to tell when the arm is level!
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Old Jun 19, 2010, 05:40 AM
Registered User
Joined Mar 2009
139 Posts
It finally flies, hurra!

Hurra! My HK250GT finally flies. I bought one from the first batch last year when it came out, and have had many issues with it, almost giving up.
First the canopy was very out of shape and cannot be used, then several screws were found to be over tightened / stripped from factory assembly, then the feathering shaft snapped on first spool-up with a lot of damage as a result, then after rebuild the swash pitch ball snapped on next flight, another crash... After yet a rebuild it now finally flied for a whole battery's worth of time

It was not stable, neither in cyclic nor tail respons though. Several links had a little binding to them, and after fixing that, replacing the 401B gyro with another one of same kind (first one had some unexpected jittering), putting tail servo ball as close to MKS DS480 tail servo hub as possible (5 mm), going to 37mm Align tail blades with Align SE grips (with built-in chinese weights), making sure tail was smooth and adding some delay to the gyro (although servo is digital), it actually flies ok now.

Now I need a canopy that actually fits with HXT 900 cyclic servos. Please let me know which canopy can fit this setup.

Using the Turnigy 2627-4200, 12T, 25A Turnigy ESC, giving me around 5 mins of gentle setup flight before 800 mAh batteries goes to around 3.7-3.8 volt. My idle-1 (79% flat) hover headspeed is measured to ~4550 at start and ~4050 at end (with sound frequency analysis). Is the 500 rpm drop to be expected?

Adding delay (75) to the gyro makes tail more smooth with less bounce on stop. Did the same for my 450 with same gyro, although analog servo was used there. I still have a little bounce though... Normal to need delay on digital servo?
Trying to get a pair of the chinese weights from Heim Joint after seeing his Youtube clearly showing the SE grips to hardly have any effect.

T250 WEIGHTED GRIP TEST (4 min 37 sec)


Might need some stiffer blades. The plastic ones seem very soft. Might try the carbons from HK, but they are noted to be shorter than Aligns, possibly effecting stability (anyone have experience here?).
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Old Jun 19, 2010, 05:43 AM
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Joined Mar 2009
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Quote:
Originally Posted by bwoollia View Post
Any thoughts on leveling the servo arms? Because the servos are angled, it's hard to tell when the arm is level!
I made all three cyclic servo arms horizontal to the ground on 0 pitch, just eyeballing them.

Had not thought of perhaps having servo arms parallel with each servo on 0 pitch - anyone done that? Recommended?
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Old Jun 19, 2010, 10:27 AM
Low rates are for wimps
bwoollia's Avatar
United States, CO, Colorado Springs
Joined May 2008
3,309 Posts
Aligning the servo arms with the servos would be a bad idea, they need to be level. There's just no good reference on the heli to level them that I can see!
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Old Jun 19, 2010, 04:27 PM
Low rates are for wimps
bwoollia's Avatar
United States, CO, Colorado Springs
Joined May 2008
3,309 Posts
Quote:
Originally Posted by holsen View Post
Now I need a canopy that actually fits with HXT 900 cyclic servos. Please let me know which canopy can fit this setup.
The stock canopy will work fine. Take some hot water (near boiling), and holding the canopy grommets fill the canopy with water. Be careful not to burn yourself of course. Swish the water around, the canopy will become soft. Squeeze the top and bottom together a bit after dumping the water, hold it like that while it cools. The canopy should fit fine after that.
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Old Jun 20, 2010, 01:53 AM
Registered User
Joined Mar 2009
139 Posts
Quote:
Originally Posted by bwoollia View Post
The stock canopy will work fine. Take some hot water (near boiling), and holding the canopy grommets fill the canopy with water. Be careful not to burn yourself of course. Swish the water around, the canopy will become soft. Squeeze the top and bottom together a bit after dumping the water, hold it like that while it cools. The canopy should fit fine after that.
Good tip. I will try it if needed with a new one, perhaps a locally available Align canopy. My issue was that the right upper HXT900 servo horn and link ball cannot fit under the canopy, so it needs to be wider there. Don't know if that's a normal problem.

My original canopy has a wider arc on it's left side, but on the right the arc is going inwards instead of outwards, so not knowing the boiling water trick, I tried to first bend it a little, then cut out a whole, but it doesn't work out good.
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Old Jun 20, 2010, 07:26 AM
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Pepelatz's Avatar
Staten Island, NY, USA
Joined Aug 2006
285 Posts
To reshape the canopy you can also use a hair dryer. My canopy now not only clears servos, but also fits 1300mah battery.
For proper servo setup check excellent Finless Bob's videos.
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Old Jun 20, 2010, 08:51 AM
AMA # 949551
rikybob's Avatar
USA, FL, Orlando
Joined Oct 2009
2,096 Posts
Introducing myself!!!

Hi all!

I have finally finished reading the thread and am joining the ranks of the 250 owners!

A bunch of great guys and great posts!!

I joined the "dark side" back in March and bought a Blade SR.....I won't bore you guys but WHAT A MISTAKE!

I finally made it flyable and actually enjoy it but it costs a FORTUNE to fly and even if you can get the parts for it they are $$$$$$!

It resides on Fleabay and will be gone in a few days!

Slipped over to the HK 450 GT and REALLY enjoy it but like the 250 class as well.

HK is selling their HK 250 GT now for about 1/2 price so's I have one on the way!

The condensed version that I have read is that the tail box sux and in general it is a squirrelly machine???

I look forward to the impending misery!

Best to all!

Brian
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Old Jun 20, 2010, 09:11 AM
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los08's Avatar
Joined Dec 2004
30 Posts
Quote:
Originally Posted by rikybob View Post
Hi all!

I have finally finished reading the thread and am joining the ranks of the 250 owners!

A bunch of great guys and great posts!!

I joined the "dark side" back in March and bought a Blade SR.....I won't bore you guys but WHAT A MISTAKE!

I finally made it flyable and actually enjoy it but it costs a FORTUNE to fly and even if you can get the parts for it they are $$$$$$!

It resides on Fleabay and will be gone in a few days!

Slipped over to the HK 450 GT and REALLY enjoy it but like the 250 class as well.

HK is selling their HK 250 GT now for about 1/2 price so's I have one on the way!

The condensed version that I have read is that the tail box sux and in general it is a squirrelly machine???

I look forward to the impending misery!

Best to all!

Brian
I started down the HK250 road. After going through this thread I've decided
not to go the 250 route and put the money into a bigger machine. Brian
I'm in Orlando PM me if you need a extra NIB kit HK250 kit cheap..
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Old Jun 23, 2010, 05:13 PM
AMA # 949551
rikybob's Avatar
USA, FL, Orlando
Joined Oct 2009
2,096 Posts
Quote:
Originally Posted by los08 View Post
I started down the HK250 road. After going through this thread I've decided
not to go the 250 route and put the money into a bigger machine. Brian
I'm in Orlando PM me if you need a extra NIB kit HK250 kit cheap..
Good to speak with you Carlos,

I will get with you next week!

B
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Old Jun 23, 2010, 05:30 PM
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Barcelos - Portugal
Joined Apr 2003
31 Posts
Feathering shaft

Hi,

Is there any trick to disasemble the head in order to change the stock feathering shaft for the align one?

One of the screws I can turn it indefinitly and it won't come out. The other one comes out but I can't pull the blade grip.

Any ideas?

Thanks,

J Fonseca
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Old Jun 23, 2010, 08:39 PM
Excellence is Expected
MakMov's Avatar
Aurora, Colorado
Joined Nov 2005
3,736 Posts
Quote:
Originally Posted by J Fonseca View Post
Hi,

Is there any trick to disasemble the head in order to change the stock feathering shaft for the align one?

One of the screws I can turn it indefinitly and it won't come out. The other one comes out but I can't pull the blade grip.

Any ideas?

Thanks,

J Fonseca
Yeah, because it's in the shaft and that is just spinning in the head. You should be able to push the shaft through the otherside. You just need to pull the grip off. Once the bolt is out the only thing kind of holding it on maybe is some extra loctite on the washer or something.
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