Need help selecting power combo for T-Rex 600

[Neil_J]

Hi,

I ordered a T-Rex 600 kit today from ReadyHeli... Should be on my doorstep tomorrow afternoon. I picked the KX016006A G10 fiberglass Kit w/ XL motor & ESC: http://www.readyheli.com/KX016006A_TREX_600_Fiberglass_GF_Kit_Combo_p/kx016006a.htm

I haven't ordered the electronics yet. Still have a few questions to ask. :) Mainly I need to know what is a good power combo that would meet the following criteria:

- Needs to lift a Canon Digital Rebel and custom pan/tilt mount (something comparable to an Askman)
- Preferably charge on my Triton 2+Equinox (i.e. 7A charge, 5S max -- charging 2x 5S to make a 10S setup would be ok). Finding the extra $300 for a TP1010 + balancer would be hard right now.
- If possible, I would like to make this heli dual use (i.e. light sport/circuit flying), I don't mind changing a motor+pinion and blades on weekends to do so.

So is this possible or am I asking too much?? I'll eventually buy another .50 size and devote one to AP, and one to sport flying, but no clue when that will be.

[trackhead]

I'm lifting a Rebel XTI and other small HDV cams with a custom front mount. No problems at any elevation up to 11,000ft.

I'm running stock everything, with Air Thunder and Flight Power lipos at 6s.

Couldn't be happier with the economics and flight characteristics.

[Neil_J]

I'm lifting a Rebel XTI and other small HDV cams with a custom front mount. No problems at any elevation up to 11,000ft.

I'm running stock everything, with Air Thunder and Flight Power lipos at 6s.

Couldn't be happier with the economics and flight characteristics.
That's awesome, I hope it will really be that easy. When I first started reading in this section, it seemed like a lot of people were heavily modifying their rigs, esp. the T-Rex 600.. Things like longer-than-stock flat-bottom blades, lower headspeed, large batteries, etc. So all this stuff is overkill?

[crewchief]

When I first started reading in this section, it seemed like a lot of people were heavily modifying their rigs, esp. the T-Rex 600.People modify cars, motorcycles, you name it, but they rarely do so without introducing undesirable side effects. I agree with trackhead, I've got a stock 600, and it works great as is. I tried the custom blades and hated them - went back to the stock Align white blades which are rock solid. I figure if my T-Rex won't lift it, and I want an electric that will, I should build a Maxi-Joker. As a career design engineer, I recognize the T-Rex and Maxi-Joker as elegant and well thought-out designs, and a lot of other stuff out there that is appalling junk. In fact I was seriously considering buying a new heli (which shall go unnamed) until yesterday when I downloaded the PDF construction manual and saw what a terrible design kluge the frame was. My T-Rex is a work-horse, but I guess if someone just wants to tinker for the sake of "improving" what a team of engineers has taken years to perfect, that's OK too. These days I'm in the business of selling pictures, so I'll trust the professionals to do the engineering work.

[Neil_J]

People modify cars, motorcycles, you name it, but they rarely do so without introducing undesirable side effects. I agree with trackhead, I've got a stock 600, and it works great as is. I tried the custom blades and hated them - went back to the stock Align white blades which are rock solid. I figure if my T-Rex won't lift it, and I want an electric that will, I should build a Maxi-Joker. As a career design engineer, I recognize the T-Rex and Maxi-Joker as elegant and well thought-out designs, and a lot of other stuff out there that is appalling junk. In fact I was seriously considering buying a new heli (which shall go unnamed) until yesterday when I downloaded the PDF construction manual and saw what a terrible design kluge the frame was. My T-Rex is a work-horse, but I guess if someone just wants to tinker for the sake of "improving" what a team of engineers has taken years to perfect, that's OK too. These days I'm in the business of selling pictures, so I'll trust the professionals to do the engineering work.

I can understand your argument, my job is mostly software these days, but in years past I did a lot of mechanical engineering with SolidWorks. Can definitely relate to people "defiling" a well designed product in the name of modding, just to modify something.

However I was referring more to the process of converting a T-Rex 600 (designed for 3D aerobatic maneuvers) to an Aerial Photography rig (something docile and free from vibration.. can handle a few pounds or more of payload, and most importantly hovers well). In that sense, I wouldn't call that defiling a well engineered product... it's simply modifying it to fit a unique application.

So the real question is, are any of these modifications needed for AP? (the same question could be asked for different levels of use, i.e. are they needed for an amateur rig, and also if they're needed for professional rig). I'm more than happy to keep the stock configuration as recommended to me by two people so far.. but I would like to hear from a few people who went with something else (i.e. running 8-10s packs, larger blades/lower headspeeds, etc) and why, as I know there are a few of them out there.

[SeismicCWave]

All mechanical designs are compromises for specific goals. Model helicopters are design to fly at a specific weight to do a specific task. Most helicopter blades are symmetrical so that the helicopter will fly right side up and upside down just as easily during an aerobatic maneuver. A fully symmetrical airfoil is a compromise. So if you do not plan to fly upside down a well design set of semi symmetrical blades or flat bottom blades will be more efficient. How much more efficient? I have not seen any reports on real tests that shows measurable results yet.

Longer blades have the same design philosophy. An aerobatic airplane has a low aspect ratio wing to aid in the responsiveness of the plane. A sailplane or a cargo plane has narrow and long, high aspect ratio wing for lifting efficiency. Same as an AP helicopter intended for heavy lifting of airborne camera and downlink equipment.

Slowing rotor head speed is to change the vibration frequency and/or adjust to the efficiency of the longer blades with different foils.

Any change you make is a compromise. The effect may be desirable or undesirable. Everything has a cost and a benefit involved in this world. So all you can do is weigh your pros and cons and decide if the benefit outweighs the costs.

[crewchief]

One thing for sure that can help is the 440mm flybar and some flybar weights, and of course the AP2000i.

[MarkWebber]

Mine is a bone stock 600 with the L motor running 6s2p 4400's. It's been picking my 5.5lb gasser mount because I don't have the lighter 600 class mount done yet. Doesn't even drop my flight times noticably.

When I'm ready to pretend that I can do 3d, I just pull the mount and go for it. It's a great dual purpose electric.

[Neil_J]

...and of course the AP2000i.
No problem there, I've already started on a heli stabilization system that will put all others to shame (main selling point is 6-axis IMU with Kalman filter, i.e. true 6-axis stabilization). I do this stuff for a living, so it should be fun :)

[Neil_J]

Mine is a bone stock 600 with the L motor running 6s2p 4400's. It's been picking my 5.5lb gasser mount because I don't have the lighter 600 class mount done yet. Doesn't even drop my flight times noticably.

When I'm ready to pretend that I can do 3d, I just pull the mount and go for it. It's a great dual purpose electric.
Yep, that's it, I'm going 6s.. Seems the best choice for a dual-use machine. Did a ton of research on various forums today and that seems the way to go. Plus I can keep my 600XL motor instead of spending a ton on a new one. I can always switch later, but the 6s should be ok to start with.

[bullaculla]

This graph will tell a lot. The difference between 620 symmetrical blades and 610 semi symms. The 620s are longer and heavier so no surprise it pulls more amps, but they can auto. I've done a few test ones fully loaded from about 15 feet.
http://photos.imageevent.com/bullaculla1/heli/large/8-28%2061vs62.jpg
And this is on 10s system. I wouldn't try 620s on 6s. Also, look how low the amp draw is. over 8 minute flight and only pulled out 2400mAh on the first flight (sorry, this graph was recorded without the camera) The flights were a mix between hovers and hard full pitch climbouts. Also you cant see the performance, but the spikes are the full pitch climbs, at 13lbs with camera, it can climb harder and faster than my stock 7lb 3D trex600 on 6s. And at the end of the flight, the motor, ESC and lipo are barely warm. An XL after a 5 minute 3d session will be around 180degrees. This will keep my reliabilty and life of my components up. Even smaller helis like logos are using higher power systems for better performance.
The only other mod I did was add a alum base frame plate because i'm using an underslung 360 pan mount.
http://photos.imageevent.com/bullaculla1/heli/large/CIMG2496.JPG
All that weight hanging from those little LG tabs cant be good. Its just 4 tiny nuts supported by a thin pieces of plastic.
BTW, I have 2 600s. one designated for AP and another for fun. But when I have important shoots, i bring the play one along just in case. Being a professional wedding photographer, I know you gotta have 2 of everything :)

:edit:
something was wrong with my FDR that day. Voltage should've been 42V peak.

[Neil_J]

This graph will tell a lot. The difference between 620 symmetrical blades and 610 semi symms. The 620s are longer and heavier so no surprise it pulls more amps, but they can auto. I've done a few test ones fully loaded from about 15 feet.And this is on 10s system.
bullaculla, you were one of the people I referred to with modified 600E's. Thanks for sharing the info. Yes the FDR graph helps a bit, looks like current draw goes up on the larger blades. Funny, 20mm doesn't seem like a lot :roll:

But when I have important shoots, i bring the play one along just in case. Being a professional wedding photographer, I know you gotta have 2 of everything
So basically the 10s+special blades helps with large payloads and longer flight times, but is not 100% mandatory for the average user. And a stock 600E would even get a pro aerial photographer by in a pinch :)


Edit: who makes the aluminum base plate?

[bullaculla]

So basically the 10s+special blades helps with large payloads and longer flight times, but is not 100% mandatory for the average user. And a stock 600E would even get a pro aerial photographer by in a pinch :)

I totally agree! Piton has been shooting video in 10k ft elevations with his stock 600.
Actually, Its been a long road for me. I started out with a stock 600. but was unhappy with flight times, and it gets a little hot here anyway. I have a vid of my stock 600 with stock white align CF blades hauling a small video camera. We were at the early stages of testing. No video preview downlink, and it was my first time flying an underslung. It was like trying to fly a pendulum! :shock:
http://photos.imageevent.com/bullaculla1/heli/trex600-APtest.wmv
It works fine. But I just wanted better reliabilty. And a little auto-ability(?) There is even a full pitch climbout towards the end of the vid, and power was impressive.
Also, the blades are not special. I am now using the NHP 620 razors which are just 3d blades. The 610s semi symms provide more lift and pull less amps, but balloons more with the gusty tradewinds we have here. So on a low wind day, i'll fly the semi symms.


Edit: who makes the aluminum base plate?

Sorry, I cant tell you. I'll send you a PM after I talk to the guy :wink:

BTW, i am one of those guys who cant leave well enough alone. In fact my beautiful camera ship is all over my living room floor cause I dont like my wiring! I like the way it looks, but it is a little loose and may be vibrating.
http://photos.imageevent.com/bullaculla1/heli/large/sprtn1.jpg
and I LOVE my tango!!! :D
http://photos.imageevent.com/bullaculla1/heli/large/IMG_0033.JPG

I am a showoff! :P but I will admit, i am not a professional AP pilot yet. I haven't made a dollar with my rig yet. A real pro would look at potential income versus equipment investment.

Neil, did you read the "power system" sticky in the 600 section? and also "power systems that work" thread.
Lots of good info for high voltage systems.
Also, there is a 12s trex 600 in the FS section! :shock: