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HelicopterAerial Photography and Video › Looking for suggestion on T-rex 700 Electric conversion...
10-24-2009 08:03 PM  8 years agoPost 1
lele

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italy

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Hi guys, I am looking at the best motor for and pinion suggestion for a T-rex 700 conversion.

I know that the best choice should be a Xera motor, but I have a problem of time, I need to get all parts immediately for a job I should do in the next weeks.
I plan on lifting about 8.8Lb with this heli.

What is the best second choice for the conversion after the Xera?

I will use 12s 5000Mha and Power Jazz

thanks
lele

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10-24-2009 08:09 PM  8 years agoPost 2
46Taylorcraft

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AZ

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A Xera really is the best choice, but if you want an affordable motor that is similar to a Xera in terms of size/price you should look into a Scorpion HK-4035-400.

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10-24-2009 08:37 PM  8 years agoPost 3
lele

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italy

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thanks Dj, what pinion would you suggest with the HK-4035-400? What shaft diameter is that?

I have heard of some bearings failure with the scorpion..am I right?

Did you ever had any problem with it?

Thanks
lele

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10-24-2009 08:50 PM  8 years agoPost 4
46Taylorcraft

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AZ

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I only had one for a short period of time. it had an 8mm shaft that was turned down to 6mm at the output end.

As I recall the Trex 700 main gear is somewhere near 165 teeth. I'd say a 16 tooth pinion if you are going to be using a .7 module main gear should get you close to 1600 rpm on 12s.

The Trex 700 head is not very desirable for AP. It is a very stiff head and requires a higher headpseed than typical AP flights require or else it will "wobble".

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10-24-2009 09:56 PM  8 years agoPost 5
papatango

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Toronto, Ontario, Canada

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I'm with PS1 on the head issue. Check out F1Rocket's build thread in the F3C section on converting a 700 for e-powered precision flying.

You should also look at the PS1 mods and KDE parts kits for some inspiration.

PT

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10-24-2009 09:59 PM  8 years agoPost 6
lele

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italy

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thanks guys for suggestions.

I was also looking at this motor:

http://www.espritmodel.com/index.as...ROD&ProdID=9192

or what about an Actro 32-3?

what do you think?

thanks

lele

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10-24-2009 11:42 PM  8 years agoPost 7
Louisiana Helicam

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West Monroe, LA

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700E works fine for AP. I use one full-time. The client, pictures, and money have yet to see a difference between any machine I've owned.

http://www.louisianahelicam.com

Mine is all stock with a Scorpion 4035-560kv
Kontronik Jive 80+ HV
Outrage XP 12S 5000mah

I use this machine for stills, panoramics, and 3D. You may want to go with the motor they suggested if you want the lower headspeeds. I'm running around 1900.

www.louisianahelicam.com

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10-24-2009 11:58 PM  8 years agoPost 8
46Taylorcraft

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AZ

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700E works fine for AP.
at the headpseed you are running I don't doubt that.
I'm running around 1900.
But that's awfully high and inefficient for AP work. You could reduce your current draw considerably if you could drop the headspeed down to 1400. But at that speed the head would induce a pronounced wobble.

Have you tried to shoot video with it yet? I built two Trex 700s for customers earlier this year and video from them at lower headspeeds was unacceptable. I had to change the rotorheads.

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10-25-2009 12:40 AM  8 years agoPost 9
lele

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italy

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Now that's sad since I am going to do mostly video work with the T-rex 700..how about putting a Kasama head on it? would it be smooth at low rpm?

thanks
Lele

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10-25-2009 12:54 AM  8 years agoPost 10
46Taylorcraft

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AZ

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I don't know about a Kasama head but with a Raptor 90 head it was pretty good.

There are some mods that can be done to the stock head in the thread that PT referenced above that may help.

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10-25-2009 04:24 AM  8 years agoPost 11
Louisiana Helicam

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West Monroe, LA

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You could reduce your current draw considerably if you could drop the headspeed down to 1400.
I use the same machine for 3D. That headspeed would be too inefficient for me to run the throttle curve that low.

I don't do video. Not enough market for it nor time to justify it here. I stay busy enough with 10-minute still jobs.

www.louisianahelicam.com

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10-25-2009 05:02 AM  8 years agoPost 12
iflybyu77

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Fort Wayne, IN

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I'm with PS1 on this one. The Trex head is a tad stiff for video. You want SLOW and almost laggy response in a video machine. Sloppy blades even help..

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