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first heli build complete - now some questions

Old 12-01-2007, 10:37 PM
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malavivius
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Default first heli build complete - now some questions

I finished the build of my trex 450 SE V2.

i have a DX7 and have it all set up ok, normal mode pitch curve is about -2 degrees at low stick, 0 at mid and +9 at full stick, but in throttle hold it's linear (-9, 0, +9).

should i set the throttle hold curve more like normal mode or even positive (+1 degree pitch) at low stick? I'm comming straight from a fixed pitch heli, where if i got into problems i would just rip down the throttle. On this collective pitch heli, if i did that after hitting throttle hold I' probably slam the heli into the ground and into a million pieces.

Also my kit came with carbon blades but i'm leaving thoes in the box untill i get past my first few crashes. i've got 325 wood blades on it now, did anyone find the blade grips extremely tight? the foam blade holder is no use to me because it feels like i'd snap the blades if i tried to fold them back.
Old 12-02-2007, 01:11 AM
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BryFlyGuy67
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Default RE: first heli build complete - now some questions


ORIGINAL: malavivius

I finished the build of my trex 450 SE V2.

i have a DX7 and have it all set up ok, normal mode pitch curve is about -2 degrees at low stick, 0 at mid and +9 at full stick, but in throttle hold it's linear (-9, 0, +9).

should i set the throttle hold curve more like normal mode or even positive (+1 degree pitch) at low stick? I'm comming straight from a fixed pitch heli, where if i got into problems i would just rip down the throttle. On this collective pitch heli, if i did that after hitting throttle hold I' probably slam the heli into the ground and into a million pieces.

Also my kit came with carbon blades but i'm leaving thoes in the box untill i get past my first few crashes. i've got 325 wood blades on it now, did anyone find the blade grips extremely tight? the foam blade holder is no use to me because it feels like i'd snap the blades if i tried to fold them back.
Your normal curve is right on from what I have been told. I am new also.

From what I have been taught, the throttle hold pitch curve should be 100% linear, same as St-1 and St-2 pitch curves.

I have also transitioned to the TREX from a model where you bail by chopping the left (throttle/pitch) stick. I have been taught that with the TREX, you must get used to using the throttle hold switch to land, or if you get into trouble, instead of cutting the stick. I have only been hovering my Heli so far, but this has seemed to be good advice.

HTH

Bryan
Old 12-02-2007, 04:24 AM
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Default RE: first heli build complete - now some questions

It's fairly important that your blades are not too tight. Make sure the nuts are not too tight, if the blades are sticking in the grips sand them down until they are looser, not too loose.
Old 12-02-2007, 07:38 AM
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Default RE: first heli build complete - now some questions

Thanks,

I sanded them back a little and now they're alot better, but still firm, which i'm guessing they should be.

more questions,

I want to know how people set thier "failsafe". Throttle hold on with some positive pitch? zero pitch? i figure either way you're gonna crash right?

Also i'm a bit tail heavy, but can't see any way out of that problem, will a bit of trim be ok to use or should i add some weight to the nose?
Old 12-02-2007, 08:23 AM
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Default RE: first heli build complete - now some questions

i use a linear throttle hold, just get use to when landing or in trouble hitting the throttle hold.....dont kill the throttle and you should be ok, seeing how if you were already hovering you had to be over 50% throttle when you hit throttle hold you will be in positive pitch, or atleast close enough....then you can auto-rotate back down to the ground.
Old 12-02-2007, 08:29 AM
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Default RE: first heli build complete - now some questions

Regarding tail heavy, just move your battery as far forward as you safely can. If you (or when) you buy some more batteries if you don't use the standard Align ones, in other words cheaper Taiwan jobbies you will find they are always heavier. I thought this was a bad thing at first but then found if you go for a scale fuselage you actually need the extra weight, scale always goes tail heavy.
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Old 12-02-2007, 12:52 PM
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Default RE: first heli build complete - now some questions

I have a pair of the Kong Power 2200 mAH 25C packs. These babies are heavy enough to where she is actually just a bit nose heavy! I just use a bit of negative elevator trim to compensate.
Old 12-03-2007, 06:36 AM
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Default RE: first heli build complete - now some questions

yeah i'm only using the stock align lipo at the moment, but will get more soon. I've read on some posts that the stock lipo isn't the best quality, with some swelling up after a short time.

I guess for lipo's i should be staying around the 2100-2200mAh. Do they start getting too heavy after that?

I'll try to get used to hitting throttle hold instead of cutting throttle / collective. This is going to be the hardest part for me to learn I think, it's just a gut reaction at the moment to rip down the stick.
Old 12-03-2007, 08:13 AM
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hennesseylord
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Default RE: first heli build complete - now some questions

u might be able to find some 2500mah lipos that would work, thats the biggest i could find to fit my falcon.....havnt looked for trex lipos yet, but im sure its going to be about the same.
Old 12-03-2007, 08:41 AM
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Default RE: first heli build complete - now some questions

As heavy as my Kong Power packs are at 2200, I can't imagine what a 2500 mAH pack would be like!
Old 12-03-2007, 11:54 AM
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Default RE: first heli build complete - now some questions

Fly at negative two positive 11 in normal mode. Don't sand or mess around with main blade hubs. The wood blades typically fit tighter than carbon. Always transport your machine with blades folded back and secured to the tail rotor. If you can't turn the blades, loosen the locknut. Whether RC or full-scale, flying helicopters is all about discipline. There's only one right way. Finless Bob's way.
Old 12-03-2007, 02:56 PM
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Default RE: first heli build complete - now some questions

you don't understand, I couldn't fold the blades back even if the locknuts were totally removed, i had to sand them.

I would have made a lot more mistakes and probably still be building the heli if it wasn't for Finless' videos and other build logs on here.

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