T-Rex 250

[Orfink69]

Hi all,

Need a little bit of help from all of you in the know

Having just purchased a new project as above, kind courtesy of robgt there are one or two bits I'm going to need to purchase to complete the build, that is hopefully where you come in.

I've bought the 250 in kit form, so need to get the cyclic and tail servo's plus a gyro and would welcome your advice as to the best to get for this little heli.

At this stage I have no idea what this little beast is capable of, but from what I have read it can be a wee bugger to tame, I'm assuming I can tone it down a little until I get used to it?

Every little bit of input would be useful, anyone who has read any of my previous posts will know I have a 450 pro, so that came with everything and has now had quite a few spares fitted after some unfortunate incidents with the ground so with this one I'd like to get it right from the start.

Thanks

Ian

[acwman]

The standard 410 servos on the cyclic, I found pretty good. Never had any problems and seem a tough reliable servos. The standard gp750 gyro has been good on my other 450 helis, and is the one they supply with the combo, so I'm guessing it would be a good choice.

As for the tail servo, I went with a bit of an oversize 9257, which I had the least issues with, and held very well, coupled to a Logictech LTG2100t.

[Sao]

I am also using the stock servos (align 410) and they are pretty good for the price. I have had some issues with the tail and in the end went with a Spartan 760 gyro and JR DS3500G tail servo and this seems to have ironed out the issues. As for taming it, it is possible to dull it down a bit but the 450 pro is going to be much easier to fly than a 250. If it were me I would put the 250 on hold and concentrate on setting up and learning on the 450 first.

[heliboy]

i would get a bit competant with the 450 pro first then maybe move onto the 250 as can be a little twitchyer.....

However if you are stuck for space then practice on the 250...

[Orfink69]

i would get a bit competant with the 450 pro first then maybe move onto the 250 as can be a little twitchyer.....

However if you are stuck for space then practice on the 250...

Thanks for all the replies guys.

At the moment I'm only looking to build the new one and set it up, won't be flying him until I'm a little steadier with the 450

It's a little project for me while the wife is at her sisters in a couple of weeks, keeps the mind occupied and also saves her moaning about the mess on the dining table

Part of the enjoyment for me is building, I'm an engineer by trade and this is just another way of keeping the hand in

[J-S-Q]

I have a 250 with all the standard Align electronics and it flies great (although I don't fly 3D but it handles loops/flips etc perfectly well with no tail holding problems). Having said that, I really only use it for hovering practice/fun at home because while it is actually very stable the real difficulty is that it's very hard to keep track of a heli this small once you start flying it around properly. So I've now set it up to be very tame with low cyclic throws flybar weights and a low throttle curve (70%) -great fun for flying at home. You can fly for 8 minutes with a setup like that but it would be less suitable for outdoors I would think.

One tip definitely worth mentioning is to make very sure that all you links are very free and smooth as it flies quite poorly if they are tight so it might be worth buying the ball link sizing tool.

Oh yeah... be careful with the screws as they are fairly easy to strip.

[heliboy]

yeah if the kit you bought form robgt is the old screw selection buy the new ones....

as the old screws can be a nightmare and cheese off real easily.

[robgt]

Don't overtighten the screws when building the heli. Use finger and thumb pressure only - nothing more is needed. This is how I build mine (the one I have flown) and had no trouble with the screws.
If you go ape on them, you will have problems! (Align cheese...). This kit has the original screws in it by the looks of it (0.9mm).

I fitted a Spartan DS760 and a JR3500 tail servo to mine - overkill you might say, but it worked very well.
The Align GP750 is a good gyro and the 520 tail servo would be a good choice - not sure about the 420?
There are metal geared versions of the 410 cyclic servos available now, which I'm using in my 450 pro to very good effect. My 250 has the stock 410 servos in and they've always been fine too - choices!!

It's up to you on the wiring side of things, but I opted for the Spektrum receiver with the pins on top (rather than out of the end) and then mounted that inside the rear of the frames so the pins faced down - and all the wires plugged upwards into it... still a lot of messy wiring on such a small heli, but it worked fine

Cheers,
Rob

[J-S-Q]

I used the Spektrum with the plugs on the end -very fidly to install everything but it does come out pretty neat.

It's worth having a look at this thread -I found the "modular" approach to be quite useful when doing the wiring:

side building tips - HeliFreak

Totally agree with Robgt about only using light pressure on the bolts. Apart from one or two such as the feathering shaft bolts, they really don't have to be all that tight and don't require too much Loktite.

[Orfink69]

Cheers everyone,

I'm just having a browse of the old interweb at the moment, the Align 410's are looking favourite so far for the cyclic with a spektrum AR6100 DSM2 receiver, just need to decide on the gyro and tail servo.

Have had a look at the Futaba GY520, any thoughts anyone. Seems like a decent piece of kit, but have no experience of Futaba gyro's.

[robgt]

The 520 will fit nicely as it is smaller than any gyro available at the moment.
It should work well too - easy to configure and setup with good holding capability.

Cheers,
Rob

[Orfink69]

Thanks

Rob,

The 250 arrived all nice and safe at work this morning Thank you for an nice and easy transaction and a very quick delivery>

Have decided to go with the 410's on the cyclic, tempted with a gp750/520 combo on the tail, going for a good price at the moment so saves some pennies

As a matter of interest, ran 3 packs through the 450 tonight with NO CRASHES woohoo. OK, so they were very low hovers, but still without mishap to the heli, although some of the wifes plants weren't quite so lucky