T-Rex 600 Nitro pro, my first Nitro heli build...

Started by lavneetgyani, March 30, 2010, 11:14:36 AM

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lavneetgyani

Everything ready, only radio installation and setup pending!!

anwar

#26
Lavneet, watch out for the clunk line inside the tank.  If you used the one that came in the kit, then it tends to elongate after being soaked in the fuel, causing all kinds of funny/serious issues (including the engine running lean intermittantly, and even quitting when you are flying with less than 25% of fuel in the tank).  Just watch for it after say every few days, and snip off the excess length. 

Using better quality clunk lines help, and a header tank absolutely helps.
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lavneetgyani

cool...i will test fly and then add the already sourced 60ml header in a few weeks....where does the header go? Seems to lack that space on the Rex 600....can you post some pics of your header attachment?
Cheers

anwar

Here is how mine is mounted.  Basically drill a hole of right dia in the CF frame, and use a stand-off bolt.  There are lots methods of mounting header tanks though.

I think my tank came from an XCell Fury heli, being sold separately at one of the LHSes. It is the "stand-off bolt" that is sort of hard to find.
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lavneetgyani

Thanks man!! Extremely helpful pictures...I have the TT raptor header though!! Did you also epoxy the header to the main tank?

gauravag

Lavneet, I am using the same servos on my Raptor 50.  Hitec 5485HB.
They are great, but I think the collective demands something more powerful.
Plus with your high performance setup, shouldnt you be looking at Metal gear high toque ones ? 5645 and the likes ?

lavneetgyani

Hi gaurav, From your point it seems the Raptor 50 is Non CCPM (is that correct?)..in that case i would never use this servo on the collective!!!.....In my case(CCPM) 3 servos are working in tandem to lift the collective and I cannot see them being inadequate in torque!!

gauravag

Well yes, i overlooked that :) 5485-HB are great. What Rx battery pack you going to use ?
I just upgraded mine from a NiCad to a A123 one and its wonderful. No regulators needed . Been using this same combo ( 5485 + A123 + Futaba ) on my patternship and works great

lavneetgyani

Excellent!! 123 are the future...I have actually orderd the Align Regulator/lipo combo with onboard glow igniter as Anwar had suggested. Should be with me in a week. In the meantime I will use a 4.8v 2000mah nimh for the first few flights till that arrives!!

anwar

Quote from: lavneetgyani on April 09, 2010, 12:04:53 PM
Did you also epoxy the header to the main tank?

Lot of people use the TT header tank, since that is the one usually available locally :) 

In my case, the two tanks do not touch each other at all, but it is entirely up to you how you want to do it.  People even use double-sided tape as the starting point, and then additional jigs to ensure a secure attachment to the main tank.

You can avoid drilling a hole in the CF frame if you can find longer substitute bolts instead of one of the existing ones.  Many pictures in this thread of various header tank mounting options :

http://www.helifreak.com/showthread.php?t=39093

What ever you do, apply simple common sense building tricks, like I dropped a thin line of CA along the two tie wraps that hold the header tank on to the L shaped bracket (there is also thin double sided tape there).  This adds to protection from the header tank moving around within the tie wraps.  Such small items help prevent accidents/issues that can truly be avoided in the first place.
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lavneetgyani

so from what I understand, there is only one point of contact to the heli / frame in your setup - the bolt with the spacers? What then prevents it from dangling like a pendulum with that bolt as the pivot?

anwar

#36
It could, but the bolt and the nut (that goes with the bolt, hidden behind the frame in the pictures) are tightly fixed with thread-lock.  Has not tilted at all so far.
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vinay


gauravag

BTW how does Trexs compare with Raptors in general ?
Since I am flying a Raptor now, would be good to know . Who knows my next heli might be a Trex !

vinay

In reality I saw more raptors at jakkur than Trexs. But in Sim I liked the rex a lot lot more than the raptor. I felt I could do more 3D on a Rex rather than a raptor. This is one question even I am waiting for the answer. And I hope to read the answer not saying "Personal preference."  ;D  ;)

anwar

Obviously the big difference is that it is CCPM.  It is certainly a higher quality kit, with the Pro version coming with torque tube tail that improves tail performance significantly (which can be a problem if you hit the blades on the ground, as the gears tend to break easily), CF frames etc.  Most people do not do 3D comfortably on Raptors (at least heavy pitch pumping moves) with out some upgrades.  Raptor has some price advantage and local availability advantage, but availability of the Align range is never an issue when it comes to ordering from outside (actually it is much better compared to Raptor/TT).  And if factor in the upgrades and quality, price is also less of a factor, and things like http://www.helipross.com really helps.  

In short, when you are ready to get into 3D/advanced maneuvers, it is time to move on to something like the Trex 600 or the Knight 50.
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vinay

Anwar, I noted that in a sim when I pitch up a Trex 600 and move the aileron left and right (like moving the heli up in a snakes path), the Trex boggles down to very low head speeds. How does people like Tareq do 3D on nitro Helis?  :headscratch:

anwar

Lavneet - That above discussion reminds me that I should warn you to leave the tail blades pretty loose. In fact, loose enough that they fall on their own weight.  Otherwise you tend to lose the torque tube gears at the slightest hit of the  tail blades on the ground or even in grass.  I have changed mine about 5 times now, mostly practicing auto-rotations that did not work well initially.  

Some people even jig up something like thick aluminium rods/wires (or piano wires) under the tail fin to increase the clearance of the tail blades from the ground.  I have seen others connect their landing gears facing backwards to help with this, but I have not been convinced about the effectiveness of the same.
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anwar

#43
Quote from: vinay on April 10, 2010, 04:09:14 PM
Anwar, I noted that in a sim when I pitch up a Trex 600 and move the aileron left and right (like moving the heli up in a snakes path), the Trex boggles down to very low head speeds. How does people like Tareq do 3D on nitro Helis?  :headscratch:

Not enough data to comment on what is happening on the sim for you. 

As far a Tareq is concerned (or any full 3D flier), it is a mix of a well tuned engine, the help of a governor in maintaining a constant head-speed and most importantly, learning to realize the right about of collective/pitch (or a combination of collective and cyclic) needed to perform each maneuver.  If you watch the videos of the 3D pros which shows their stick movements, you will realize that the whole marketing talk about "our heli is capable of doing -14 to +14 pitch range" is not needed at all to do what they are doing.  They almost never take pitch to such extremes, and even when they hit extremes, that is only for a fraction of a second (a quick "pitch pump" for those thundering stops). If you keep the pitch at max, the head gets loaded and you lose head-speed quickly in most cases.
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vinay

Well that answers my question exactly!

Well when it comes to motors, a High KV motors or a 4 Cell lipoly increases the speed of 450 size heli. Is there a similar way to increase the head speed of a nitro heli, like different breed of engines specifically for 3D etc?

anwar

Yes, there are engines of different performance (mostly rpm) capabilities.

Head speed is also a factor of gear ratios (especially the pinion gears on the motor shaft, which is something you missed in addition to motor, lipo).  That is something often tweaked for electrics and rarely for nitro ones.
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lavneetgyani

#47
Quote from: anwar on April 10, 2010, 04:10:18 PM
Lavneet - That above discussion reminds me that I should warn you to leave the tail blades pretty loose. In fact, loose enough that they fall on their own weight.  \

Point well noted, will keep that in mind. I have had a friend loose those gears on the Trex 500....

All electronics/radio/battery/gyro installed and programmed. All bench tests done and pitches set for all three modes and only need to add fuel and test fly- Crazy to see how effortlessly the pitch jumps from a -14 to a +14  if one wants to set it up that way.... I have gone by the manual with -2 to +10 setup in the normal mode...

lavneetgyani

#48
Successful maiden..First a 5 minute sortie with training gear and the booster plugged in. Off with the training gear in 2nd flight. Kept it mostly in ground effect to run the rich engine in....last photo is of all the guys who helped me with the project - Roet Bindra, Ramesh Tahlan and Jagjit Singh - missing from that picture are Anurag from Nagpur with his constant over-the-phone inputs and Amit (akumar) who could not come to the field today...It was a fun 2 weeks...Over and out on the build pictures....!!

:salute:

anwar

Congrats !  The first picture stands out for its beauty :) 

Wonder why you left the glow igniter dangling from the heli :headscratch:
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