What would you do? 2nd Hand Heli

**rhysduk** · 21-02-2012 08:22 PM

Took del of a "new" Trex 250 today.
It's 2nd hand and in superb nick. It was used on a Spektrum system before, now will be used on Futaba. After connecting all servos and powering up, the swash is all over the place.

So what would you do on taking delivery of a 2nd hand heli?

Recenter the servos?
Etc
Etc

**horsham rc** · 21-02-2012 08:23 PM

You will probly need to do as if fresh setup on a new tx so yes recenter if needed

**Mslater** · 21-02-2012 08:24 PM

Take it apart completely and re-build it. Thats what I do with anything I buy no matter where it comes from and I always find one or two things that 'need doing'

**AcidDrink** · 21-02-2012 08:26 PM

Originally Posted by rhysduk

Took del of a "new" Trex 250 today.
It's 2nd hand and in superb nick. It was used on a Spektrum system before, now will be used on Futaba. After connecting all servos and powering up, the swash is all over the place.

So what would you do on taking delivery of a 2nd hand heli?

Recenter the servos?
Etc
Etc

A bit of subtrim (not trim, subtrim) will help. I can give you my old subtrim from my dx6i, servo arms were centred mechanically.
If you changed the rx already, then re-setup is necessary, I'd check mechanical (should be good as is) and then do standard radio setup from bottom to the top (as described here http://www.futaba-rc.com/faq/faq-14mz-q845.html it's for 14Mz but will work for 8fg as well), make sure you disconnect 2 wires from the motor before you do anything.

Blades are balanced, so don't take this tape off them. You can put a new one if you need, there is a blade balancer somewhere in the parts.
Glad you like the heli

**dani_r** · 21-02-2012 08:28 PM

Originally Posted by Mslater

Take it apart completely and re-build it. Thats what I do with anything I buy no matter where it comes from and I always find one or two things that 'need doing'

That's exactly what i do.

You can never guarantee what's happened to a heli, how it was put together, what's missing/broken etc.

I couldn't fly it knowing there might be something not right.

**murph** · 21-02-2012 08:29 PM

Think spektrum and futaba are completely different where channel/servo reversing is concerned. Best off starting afresh really.

**del19_82** · 21-02-2012 09:15 PM

I would do the strip down and rebuild as well. The only model that I have bought and never done this was with my 450 that I bought off a good mate & knew he had put locktite & glue in all the right places. Radio wise I would start with a fresh model as well.

**spudly** · 21-02-2012 10:05 PM

I would think if you bought of AcidDrink a full stripdown is not really necessary. The guy knows what hes doing.
A thorough checkover and full head setup is all that's needed. Ripping apart is only going to risk busting screws on a 250.
Just my thoughts and what I would do.

**scuba steve** · 22-02-2012 01:01 AM

i bought a BNF 450 sport 2nd hand from a forum member.....man, the thing was a death trap - screws missing, parts wrong way around, bits chopped down to fit (they were actually in the wrong place) etc etc

the best thing i did was to strip it down and start again, it flew beautifully after

**5exi** · 22-02-2012 01:28 AM

Originally Posted by scuba steve

the best thing i did was to strip it down and start again

I agree with Steve its the only way

**moyesboy** · 22-02-2012 10:55 AM

The centre stick position in terms of the signal fri the rx to the servos is slightly different on jr/spektrum compared to futaba...so you at least have to look at different servo disc splines on the ccpm servos or up end uP with a lot of sub trim which isn't a good thing.

**scoobystig** · 22-02-2012 01:26 PM

Originally Posted by spudly

I would think if you bought of AcidDrink a full stripdown is not really necessary. The guy knows what hes doing.
A thorough checkover and full head setup is all that's needed. Ripping apart is only going to risk busting screws on a 250.
Just my thoughts and what I would do.

i agree, you can tell whether screws have threadlock on by just loosening them quickly and then doing them back up
you will need a head setup doing and checking the linkages

and then........................................

.........................buy one of my lovely Trex 250 bodyshells for it

**rhysduk** · 22-02-2012 07:54 PM

Thanks very much guys, I thought it would need a head set-up (oh joy - i remember the pain of doing my 450!).

So with the 250 servo's and centering, do the servo's get centred and then either;
1.) the servo arms attached parallel to the heli fuselage/body/airframe
2.) servo arms attached parallel with the servo body.
I ask this because the two cyclic(?)(front two) servos on the 250 are mounted at an angle to the lower airframe IE; not parallel to the air frame like my 450

**Lynx.1677** · 22-02-2012 07:55 PM

Strip down, treat as new. The ONLY way to do it.
For setup of most heli's:

Get servo arms as close to 90 mechanically before using any subtrim. Adjust links so that swash is level, make sure washout arms meet each other when viewed from the side at midstick and then adjust your links to get zero pitch on the blades at midstick. Also make sure mixing arms are in line with the flybar cage at midstick.

If flybarless then you don't need to worry about most of that!

There is no way to avoid learning how to properly setup a heli if you want to have a nice flying one (unless you pay someone else or know someone else that will do it all for you).

It's worth learning as when you crash you will need to check/replace and perhaps set it up all over again.

This is our wonderful hobby.