Build Blog

I have noticed from the people coming to this site that many are looking for a blog about the T-Rex 550 being built.  When I built the 550 as it progressed I updated the main blog.  However seeing the popularity of the T-Rex 250 3G conversion page I have deicided to put them all together on this page so they are in one spot.  I have also added some comments and updates that were missing from the orginial.  Enjoy!

** New Addition to the Squadron! **

Well it took a along time and some deliberation but finally I brought a T-Rex 550E 3G.  Oh yes, I’m going flybarless! So why the 550E? Well I wanted to stay with electric as my flying time is limited I can just sling a battery in and go flying which is much easier.

T-Rex 550E 3G

T-Rex 550E 3G with Align 4600mAh 40c batteries

I was tempted by the Align T-Rex 600 but thought that the new technology was better and, to all intents and purposes, this will fly just the same.  It can swing up to 550mm blades so it’s a nice size.   Big enough to auto easily and “hang” in the sky but not too big to be imposing. I hope.

The eagle eyed will spot the two batteries beneath the box –  these are Align 4600mAh 40C batteries which I think will be an excellent size and provide me good flight duration.

As I build it up I will post more pictures and of course there will be 550 page in the squadron section to record all the settings.

T-Rex 550 Build Update

I haven’t had much time of the last few days to much on the 550 but here is a photo of the build so far.

T-Rex 500 build photo #1

T-Rex 500 build photo #1

A picture says a thousand words so another 100 won’t hurt but as you can see I have built the frame up and slotted the head in. The 3G head comes pre-built and looks magnificent in the polished silver and black.   The skids go on early and it makes it easier to build and move around the bench.

Align does get some grief about the quality of its parts and so far I have to say this looks okay.

Next steps are fitting the servos and then the tail..

T-Rex 550 Build Update #2

Just spent another couple of hours in the cellar T-Rex 550T-Rex 550and this is the current build status.  It’s the first time I have put a torque tube in, normally I have to faff with a belt but this was a lot easier!  So far so good on the build, even though the canopy is on I still need to put all the electronics in properly that is normally the bit that takes ages..

550 Maiden flight!

Well yesterday was the maiden flight of the 550. After doing some reading on the internet I decided to fit an external BEC.

It seems there have been problems with the one that is built into the ESC and I didn’t want the new heli to turn into a lawn dart. In the end I opted for the Castle Creations Pro BEC (see here at Fast Lad) and fitted it with no problems.

On to the flight. I have to say I double checked everything and then gave it a go! Well it was bloody awful, it had the tremors and then when I went to idle up it sounded like it was going to explode!

Castle Creations PRO BEC

Castle Creations PRO BEC

Quickly landing it I realised the pitch and throttle curves were wrong (school boy error), this would solve the insane throttle jump but as to the quiver I changed the Elevator and Aileron gain to the 11’o’clock position and tried again.  This time it was much better but the tail wasn’t locked in.  Spent a few minutes messing around with the gain and eventually got it pretty stable enough to fly it around.  However due to the pitch/throttle curve error I had stripped a tooth off the main gear and 3G is very sensitive to vibrations so really that was as much as I could do.

Still initial impressions are very good and I can’t wait to get the new main gear on and get it in the air to tweak it further.


Doh! Can’t believe I forgot to mention this in my last post but on my 550 I have the same vibration in the tail fin that a lot of people have been having (see here) so I have changed my 550 tail fin with one from the T-Rex 600.

550 tail with 600 fin

550 tail with 600 fin

I also changed the tail supports to the 600 ones as they are stiffer, though you do have to take the horizontal fine off or the tail blades will clip it.

600 tail supports on 550E

600 tail supports on 550E

The current theory is that the 550 fin is quite thin and is resonating to the natural frequency of the heli. As the 600 fine is thicker it should resonate to a different frequency.


Well 2 months on I am still very happy with the 550. I can only describe it as a supercharged, I haven’t worked out the power to weight ratio and compared it to other helicopters but I can only imagine it is near the top. Being totally honest, it’s almost too fast. I am trying to learn 3D and the speed it can do things means when an attempt at a trick goes awry it can be a handful. When I first got the Protos I thought that was really fast and edgy but this puts into to shame.


On the battery front, I initially brought 2x Align 4600mAh which have stood up well and I really like. The only downside has been that I comprised capacity for weight. Really for the 550 you need 5000mAh ones. When I run the 100% throttle curve I put back in over 80%, this is not recommended. Therefore a runtime of 4mins 30s is needed. If you use the 5000mAh you would be able to get the full 5 mins. As always though, how you fly will influence this but I don’t it’s too radical the way I fly. 🙂 To this end recently I brought 2x Turnigy Nano-Tech 5000mAh batteries. (Smart flyers will note you cold use these in a 90 size electric..)


Having said the above and having lived with it for 2 months the 550 is an excellent helicopter. The quality of the parts on the whole is good and typical Align. The components that ship with the super-combo kit work brilliantly and means you can have a complete heli in the air for under £1,000.

For me it will be an excellent helicopter to grow into and as my flying skills get better it will come into its own. If I’m honest I don’t think I could recommend it to a beginner. I don’t seem to be the only one who has had set-ups problems and had to work at on its first few flights. Additionally the power in it could be daunting and a beginner would need to lower the throttle curves and slow the cyclic to ensure it didn’t put them off rather than encourage.

All in all a wonderful bit of kit and one I love flying! More soon..

Update – 7th September
Been out flying today and found the rudder a bit too sensitive for me. I have therefore brought the Rudder into line with the Aileron and Elevator with 15% expo. This seemed to make a difference.

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