trex 600 and AP

[OneSkidShort]

Ok guys....I need some help
I have someone that's interested in starting an aerial photography company and they have asked me to look into purchasing 2 T-rex 600's that are capable of carrying a mount. He's going to handle the mount part and I'm looking at purchasing the 600.
My problem is that I'm completely new to a T-rex and I don't know what I should be ordering. For example...I had no idea a 600 didn't come with blades. Should I change the motor? Futuba sufficient or dx7? If you were to sit down and order everything you need in one shot...what exactly would you order? I only need to hover and some FF so I don't want loads of pointless bling http://static.rcgroups.com/forums/images/smilies/smile.gif
I know I'm asking alot, but hopefully (for my sake) someone is sitting there on a rainy day with some time to spare.

Thanks guys...I appreciate the help

[crewchief]

Hi OneSkidShort,

I ordered my T-Rex 600 online and had it professionally built in Texas by RC & Me. http://www.rcandme.com/catalog/product_info.php?cPath=22&products_id=1166

I paid less for the complete 600 and DX7 Tx/Rx than several combo kits I'd seen advertised. You can call and talk to Tim first to explain exactly what you want to accomplish. Tell them you want the longer 440mm flybar with weights installed, and tell them that it will never be used for 3-D, and you want it to be set up for AP, flight duration, to train beginner pilots, and to be as stable as possible in a hover. They will program the Tx without idle-up, inverted flight, etc., and set the pitch curves to work best for lifting weight.

If you order it online, make sure to write out all these details again in the remarks box.

They called me when they'd finished mine (just took a few days) and said they'd tested it in a 15 mph wind and it hovered hands-off. Music to my ears, that was, and I've got 30 hours on it now glitch-free. You'll really love the 600.

BTW if you're looking at camera mounts, the .50-sized AskmanAP pan/tilt model is too heavy and the 600 really struggles with it. It would work better with the Maxi-Joker. Also I tried a pair of semi-symmetrical 610mm blades that were supposed to produce more lift, but ended up going back to the stock Align 600mm symmetrical blades, which seemed to fly a lot smoother.

[Tonystott]

I would think that idle-up is absolutely essential for an AP ship.. with the extra weight, maintaining a good headspeed is essental for solid control, and bringing it down (or counteracting a gust which will cause it to climb) by reducing headspeed with pitch is not a good place to be.

By setting a pitch curve (in idle-up) something like this:- -8 -4 0 +5 +10, there will be a softish area just under middle stick, but full negative will firmly reduce height while retaining full cyclic contol

My $0.02

[bullaculla]

I agree with Tony. I have my normal mode setup as an idle up mode with a flat pitch curve.

Also, while I agree that a stock trex600 isn't a good platform to mount a large 360 pan mount, My 600 on 10s can lift it just fine for over 10 minutes. I only use the semi symms in very light wind conditions and with a higher HS its pretty stable. I use 620 symmetrical blades in windy conditions. Stock 600 on 6s with a 5000mAh lipo will only lift a DSLR for a few minutes.

[OneSkidShort]

Thanks guys

I really appreciate the advice. Am I even looking in the right direction in regards to the Trex or is there something else that would better suit AP that's electric??

Bill

[crewchief]

I would think that idle-up is absolutely essential for an AP ship.. with the extra weight, maintaining a good headspeed is essental for solid control, and bringing it down (or counteracting a gust which will cause it to climb) by reducing headspeed with pitch is not a good place to be.

By setting a pitch curve (in idle-up) something like this:- -8 -4 0 +5 +10, there will be a softish area just under middle stick, but full negative will firmly reduce height while retaining full cyclic contol

My $0.02

This could be true, I'll have to give it a try. I guess I'm still basing most of my decisions on 30 years of working and flying "real" helicopters. It's interesting that all the long line lifters manage without it, or maybe I just never noticed a "Flight mode" switch in any of the cockpits!

EDIT: actually come to think of it, the turbines do essentially work in "idle up" once beyond the start-up phase. There's a "detent" position on the throttle with a latch that maintains the N2 (output) turbine stage at 104% rotor speed (weird, huh?) and the N1 (compressor) stage works independently of it. So I'd say you're right - I look forward to trying it.

Do you set the thottle curve linear +100% 50% +100%?

THANKS!

[bullaculla]

Look around.
Soundwave just started a new thread with his Maxi joker2 setup, which is probably the biggest electric kit around and is designed for AP.
http://www.helifreak.com/showthread.php?t=43586
And my thread with my trex600 is around here too with all my mods.
http://www.helifreak.com/showthread.php?t=42001
But if i could start all over again, i'd get nearly the exact same setup as soundwaves. Its just a huge investment up front, while i've spent over $4k slowly since january. My paypal history is 8 pages long :mrgreen:

[crewchief]

Follow-up on the idle-up issue. I set up ST-1 throttle for 50% INH 50% INH 100%, and at half stick switched it over to idle-up. I really didn't notice any difference in flight characteristics (sweet as always) but of course I didn't have a large load installed. The builder set the pitch curve to 0% INH 22.5% INH 67%. I don't know if this is the standard setup, or whether he was specifically setting it up for AP as I had requested. I had heard that if you set the pitch curves correctly, you can control head speed and alleviate the kinds issues you were addressing. You have to consider that the NORM and ST-1 curves might be identical through the working range. Of course you can't shoot pix upside down without idle-up! One thing I know for sure - I've seen major mayhem when guys tried to chop the throttle in idle-up. What would have been minor dings turned into a major thrashing.

[bullaculla]

You should learn to use idle up modes early on, As well as never chopping the throttle. This is basic heli training.
Also, if using a gov, you need to have a flat throttle curve. like 80% straight across.
my pitch is 0-50-100 in all modes.
and throttle is 80% flat in normal and idle 1
and 85% flat in idle 2.
If you have it setup for max pitch, you get faster collective response. So if the wind dies you can catch it faster. Also, I setup my head for max pitch without binding so I can get 13 degrees if I need it, but you need to practise good collective management ;)