Trex 450 Pro build videos

[cpmboy]

Originally Posted by pinguin

You need to flip the tail grip to get a 8 degree pitch. Without flipping the tail grip, everything works alright, but if you flip the tail grip, you will get a better geometry.

I usually set my tail in rate mode first. It's not necessary, it's personal. If you can have a steady tail in rate mode, it means that you have the correct pitch. When you flip to HH mode, the gyro and servo don't need to work hard, because the tail pitch is already correct. But if you don't set the tail in rate mode, you don't know what pitch you have, the gyro and servo have to work harder to keep the tail steady.

Hi,
Thanks for sharing..so..one thing is clear.....to set the tail, its best in RATE MODE...hw do I knw that by doing the flip, I'll be getting 8 deg pitch on my tail blades?...and..(I hvnt try it yet...going to later)..is it ok to sub trim an align rudder servo and is it true that the gyro will sense it as a neautral position?...............

[cpmboy]

Originally Posted by Finless

Yes I think the Aligh gyro works much better at 8mm rather than 10mm.

Bob

hi Bob,
I decided to follow ur suggestion....do I need (after the flipping thing) to change the balls position (10mm to 8mm)?.or if I just leave it on 10mm..would it be ok?...Im using the GP780....................and can I really subtrim a rudder servo (..to be setup wt the GP780 later)

[pinguin]

Originally Posted by cpmboy

Hi,
Thanks for sharing..so..one thing is clear.....to set the tail, its best in RATE MODE...hw do I knw that by doing the flip, I'll be getting 8 deg pitch on my tail blades?...and..(I hvnt try it yet...going to later)..is it ok to sub trim an align rudder servo and is it true that the gyro will sense it as a neautral position?...............

I wouldn't use any trim or sub-trim on rudder. Better set mechanically.
Some gyro will treat trim or sub-trim as a stick input.

[Finless]

Yes still go to 8mm even with the grip flip. This gives the gyro more room / resolution to work with.

Bob

[cpmboy]

ok ...

[Jasmine2501]

Originally Posted by cpmboy

hi Bob,
I decided to follow ur suggestion....do I need (after the flipping thing) to change the balls position (10mm to 8mm)?.or if I just leave it on 10mm..would it be ok?...Im using the GP780....................and can I really subtrim a rudder servo (..to be setup wt the GP780 later)

You can, but it doesn't always work. The trick is after you put the subtrim, you need to re-bind the radio. To check if it's working right, simply observe the behavior on the bench - if you leave the stick in the center, the servo should not move - it should stay wherever it is (possibly not center). If you get a slow creep to one side or the other, it's not understanding your sub-trim. This would manifest in the air as a slow piro which can be stopped by trim entries. (A slow drift which is unaffected by trim entries indicates a different problem)

[cpmboy]

ic...for nw (myb my luck) , when I restart the gyro, the servo arm is centered at the position where I centered it wt -9 subtrim..not the original position when I mount the arm to a close 90 deg.

[scottkoblitz]

Just wondering if bob or any of you heli freaks can tell me if the tail geomtry of the pro and sport are the same? I have a EXI 450 pro that is completely upgraded to all align parts but the actual frame qark gyro and tail. I'm going to order a sport tail box since I'm a noob and don't want to strip gears everytime I touch the blades on a blade of grass. Anyways, can I use the linkage control arm and slider from the pro clone or do I need to order sport parts? I alread have the pro hub installed and have the grips flipped. I'm just wondering if the control arm is the same with the goofy geometry issue on the sport?

[isogloss3d]

Originally Posted by scottkoblitz

Just wondering if bob or any of you heli freaks can tell me if the tail geomtry of the pro and sport are the same? I have a EXI 450 pro that is completely upgraded to all align parts but the actual frame qark gyro and tail. I'm going to order a sport tail box since I'm a noob and don't want to strip gears everytime I touch the blades on a blade of grass. Anyways, can I use the linkage control arm and slider from the pro clone or do I need to order sport parts? I alread have the pro hub installed and have the grips flipped. I'm just wondering if the control arm is the same with the goofy geometry issue on the sport?

The Align Trex 450 Pro and Sport use the same control arm. However, it's still a good idea to confirm this with a visual comparison to clone parts if you want to be certain of an identical match. Some clones claim to have 99% parts compatibility, the problem I ran into (at least with HK) is they don't tell you what parts are in the 1% category leaving you to find out for yourself the hard way.

[netsurfr]

Well finally finished my 450 Pro build. Took my sweet time because this was my first build. Those Finless videos were such a huge help. Thanks Bob! I have not done the tail grip switch mod yet but will after I make sure she flies & nothing else is screwed up. Hopefully will get to hover her tomorrow & all goes well. I do have a question or 2 before I maiden her so hoping someone can answer...

1. I ended up having to adjust the pitch & aileron & upper links to get close to 0 at mid stick. I actually ended up with more like 1 at mid stick & about 10 positve & 9 negative so I'm assuming this is ok? I won't be doing 3D type flying so I don't expect to need anywhere near that -9 pitch.

2. I'm using a DX8 and the Gyro setting range on it is now -100 to 100 yet the Finless videos say I should set the Gyro (GY401) to 40/-40 but is this more like 75/-75 in a TX like the DX8?

3. I balanced the CF blades & did a test spool up on the ground. Everything seemed fine (tail moving & correcting in right direction although first time it just spun around like crazy then I searched here & found that is a sign of needing to reverse my Gyro direction & that fixed it (thanks Bob!). One issue I noticed is I saw a bit of vibration of the heli on the ground during low rpms. Seemed like by the time the throttle & pitch were at around mid stick they were gone. Vibrations were minor but is this a problem?

[Finless]

1) It will fly a little off with the pitch like that but you should correct it long term.
2) The DX8 is different than other JR/Spektrum radios. The gyro menu is 1 to 1 like Futaba. So use the gyro menu and set it to 32% to start with and that will be "about" the right amount of gain. My quark on my other V2 is running about 24% in the DX8 gyro menu so 32 if you have wag just lower it.
3) Most helis will vibrate / wobble a little on spool up because the blades are not perfectly straight out. As head speed increase centrifugal force pulls the blades out straight and vibration goes away. Perfectly normal.

Bob

[netsurfr]

Thanks Bob! Very high winds outside today so haven't been able to do much other than barely lift off the ground in my small basement.

One other question... I use an iphone app to measure headspeed and it measured 3900 rpm & that was not at 100% throttle. I'm afraid that sounds too high but then again not sure how accurate that iphone app is either?

BTW - I have the old 450 SE V2 motor (430XL) in the 450 Pro with an 11T pinion.

Originally Posted by Finless

1) It will fly a little off with the pitch like that but you should correct it long term.
2) The DX8 is different than other JR/Spektrum radios. The gyro menu is 1 to 1 like Futaba. So use the gyro menu and set it to 32% to start with and that will be "about" the right amount of gain. My quark on my other V2 is running about 24% in the DX8 gyro menu so 32 if you have wag just lower it.
3) Most helis will vibrate / wobble a little on spool up because the blades are not perfectly straight out. As head speed increase centrifugal force pulls the blades out straight and vibration goes away. Perfectly normal.

Bob

[Finless]

You IPhone app is not working correctly. I have seen that app miss-read head speed before. I am no expert on that app but when it is not reading right is is way off. When it is, it is usually within 100rpm variance.

No way with 11T and stock motor are you getting 3900. More like 2700. A 13T with stock 430L motor is about 3200.

Bob

[netsurfr]

Took another sample w/ the headspeed app outside & this time got a more reasonable reading of 2572 so I guess taking a reading inside in the basement probably messed up the app.

[ExtensionChord]

Hey you know the mod that fixes the pitch of the tail blades when the pitch arm is at 90 degrees for the 450 pro? do you have to do that for the sport as well?

[isogloss3d]

Originally Posted by ExtensionChord

Hey you know the mod that fixes the pitch of the tail blades when the pitch arm is at 90 degrees for the 450 pro? do you have to do that for the sport as well?

Good question. I was wondering exactly the same thing the other day, seeing as I own both the Sport and (just recently) the Pro.

I did the grip flip on the Pro during my build and the tail has been performing well. I didn't do the flip on my Sport as I was brand new to the hobby and wasn't aware of the flip at the time of my build. Also, there is never any mention of doing the flip on the Sport. I'm still not 100% sure if this is because there is truly a difference or if it's simply because the Sport is often overshadowed by the popularity of the Pro and its association with more experience/advanced pilots.

In my experience repairing, maintaining and ordering parts for both - it appears that they are identical tails so the "flip" may be beneficial to the Sport as well.

One obviously doesn't HAVE to do the flip because I've flown my Sport hundreds of times and (at my skill level, and only flying in H.H. mode) the tail does what it needs to do.

The tails do feel different when flying each heli but I just assumed it had more to do with them having different gyros and tail servos.

Hmm, now you've really got me wondering!

[jayess]

Hi All

Hope you can help, I am a fairly confused newcomer to the hobby.

Finless recommends a throttle curve of something like 0-50-80-90-100.

The guy at my LHS recommends something similar.

However, there seems to be a lot of chatter on the web with regards electric motors and throttle curves, some guys saying flat is better, i.e. 80-80-80-80-80 or 0-80-80-80-80.

Is this true?

If so, is this also better for the ESC and Motor as the ESC does less work at higher current?

Jayess

[Finless]

Flat throttle curves are used for idle up not normal mode. However with some of the latest ESCs with good soft start you can run a flat normal mode curve and just switch out of hold in normal or idle up. Lots of guys do it this way. Myself I prefer a lower head speed normal mode throttle ramp up for takeoff. Also while learning to hover if you do not have a normal mode curve that goes down to 0 throttle at low stick, you MUST learn to use hold. I consider not having 0 throttle at low stick in normal mode a safety issue myself especially for new guys learning.

Bob

[Waxweazle]

Thanks bob for the great videos!
I built the 450 3gx with your help!


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[DPW]

Disregard post config on tail can not be changed by control arm mod