Trex 450 Pro build videos

[Finless]

Glad to hear it! Thats what I do them for
Glad I could help.

Bob

[PilotImpersonator]

I finished my first helicopter build ever (450 Pro Super Combo) and had a fantastic first 3 flights early this morning (hovering 3 packs and doing a little fine tuning). I've been practicing on Phoenix Sim for the last couple months and was happy to finally move to the real thing.

Couldn't have done it without your awesome videos!

Thanks Bob!

[marian206]

Bob, I am setting the tail right now and I run into some issues.

Basically, when I set the lenght of the rudder control rod to 345mm as per manual, with servo arm at 90 the tail pitch control arm is way too far from 90 with the rod because the rod seems to be too short to have 90 at both ends. OK, so I increase the lenght of the rod and at 350mm (which is the maximum I think) and thus I get it almost close to 90 with the tail pitch arm having my tail servo centered at 90.

In this case, having the rod lenght at 350mm at 90 to both ends with servo arm and tail control arm, servo centerd and ball link on the servo arm at 8 mm, the slider is almost centered and the tail has zero pitch, while the tail servo (Futaba BLS251) does not bind at all with rudder travel set to 75 (end points are default 135) on my Futaba 8FG.

So in this case, by lenghtening the rudder rod as much as possible it seems I get no need for flipping the tail grips... Am I missing something here? What rod lenght have you ended with? Or the rudder control rod should not be 90 simultaneously with both the servo arm and tail control arm? Or is it possible that they have solved the tail pitch issue on the latest 450Pro kits?

[ScotY]

I just picked up a kit. I'm still amazed that Jason Krause would put his name on the box with such a mess of a tail slider design. I haven't started putting it together but mine is definitely not corrected.

[Jasmine2501]

Originally Posted by ScotY

I just picked up a kit. I'm still amazed that Jason Krause would put his name on the box with such a mess of a tail slider design. I haven't started putting it together but mine is definitely not corrected.

You can talk theory all you want, but I put mine together and flew it, and the result speaks for itself. The tail design is fine, and the overhaul of the 450 is something I would be proud to put my name on.

[ScotY]

Originally Posted by Jasmine2501

You can talk theory all you want, but I put mine together and flew it, and the result speaks for itself. The tail design is fine, and the overhaul of the 450 is something I would be proud to put my name on.

Sorry...the tail design is not "fine" by any definition especially when you consider one solution is as simple as adding a couple mm to the output shaft length. Add the fact that they allowed a bunch of cosmetic changes that make manufacturing costs go up seems to imply that there were no compromises during the design process. The grip flip is a viable fix but now you have the pushrod pushing rather than pulling for right rudder/tail. This is a "Pro" model with a premium price tag. This type of simple design flaw is really not acceptable.

[lucien]

Originally Posted by ScotY

Sorry...the tail design is not "fine" by any definition especially when you consider one solution is as simple as adding a couple mm to the output shaft length. Add the fact that they allowed a bunch of cosmetic changes that make manufacturing costs go up seems to imply that there were no compromises during the design process. The grip flip is a viable fix but now you have the pushrod pushing rather than pulling for right rudder/tail. This is a "Pro" model with a premium price tag. This type of simple design flaw is really not acceptable.

I agree after watching Finless's video. My 450 is out on the UPS truck right now so today I'll be able to look at my tailcase to see if it's still like this, but if so, the geometry is definitely not right as-is.

Besides the geometric problem, you're almost at the limits of control by the looks of it by the time you get to just hovering pitch on the tail rotor. That's bad......

Again, without even having looked at one before, I doubt there's enough force needed for right rudder to buckle or even bend the control rod (maybe you could add some more supports for it on the boom if so), so I wouldn't be too concerned about that.

But I agree - if I were align, I'd bite the bullet and fix it. Parts support would be a pain, but the tail would then be done right....

LS

[e30ernest]

Actually to fix it, I think all they needed was a longer tail shaft.

[Jasmine2501]

Originally Posted by ScotY

Sorry...the tail design is not "fine" by any definition especially when you consider one solution is as simple as adding a couple mm to the output shaft length. Add the fact that they allowed a bunch of cosmetic changes that make manufacturing costs go up seems to imply that there were no compromises during the design process. The grip flip is a viable fix but now you have the pushrod pushing rather than pulling for right rudder/tail. This is a "Pro" model with a premium price tag. This type of simple design flaw is really not acceptable.

That is all theory. GO FLY THE EFFING THING, IT IS FINE!

And yes, I understand what people are saying, but to give a quick visual inspection and decide that it's such crap that you're willing to insult Jason Krause, without even flying the thing, is a little over the top. I don't think Jason's reputation is in jeopardy because of this design, due to the fact that it flies fine, and I don't know about you, but I can't really see the "flaw" when the thing is in the air.

[lucien]

Originally Posted by Jasmine2501

That is all theory. GO FLY THE EFFING THING, IT IS FINE!

And yes, I understand what people are saying, but to give a quick visual inspection and decide that it's such crap that you're willing to insult Jason Krause, without even flying the thing, is a little over the top. I don't think Jason's reputation is in jeopardy because of this design, due to the fact that it flies fine, and I don't know about you, but I can't really see the "flaw" when the thing is in the air.

Ok, the UPS man just brought my 450 kit and so I took a close look at the tail case.

Just eyeballing it, it really doesn't look that far off. Yes, it is off, but not really by a whole lot. Neutral pitch on mine is at approx. center slider; there's about an equal amount of pitch adjust in both directions, though maybe just a hair more in the left (away from torque) direction.

Just going by memory where hover pitch was on my Shuttle and JR's from years ago, I'd say hover pitch is going to be a little bit "left slider" looking from the rear. So, yeah, it is off a little bit, because of the apparently neutral pitch at (approx) center slider design.

What makes it a little goofy is that the angle formed by the control bellcrank is more than 90degs so there's going to be some differential action in right vs. left rudder. Right rudder is going to bunch up a bit in that last little bit of travel as that angle increases.

But since the angle of the control rod vs servo arm is going to be increasingly less than 90, this differential might actually be a good thing in the air.

My fix would be making the angle of the bellcrank a little closer to 90 than it is and running a slightly longer pushrod. And maybe make the rotor shaft a hair longer.

But honestly, tho, just looking at it, it doesn't look far off enough to screw around with it. I'm going to leave mine as-is since it looks like it's still going to work ok...

LS

[Finless]

It flys fine for most people until you really start pushing the tail with backwards hard stuff and piro rate in one direction is more like an on off switch due to lack of resolution. So no it is not fine but does work fine for most people out there.

Bob

[lucien]

Originally Posted by Finless

It flys fine for most people until you really start pushing the tail with backwards hard stuff and piro rate in one direction is more like an on off switch due to lack of resolution. So no it is not fine but does work fine for most people out there.

Bob

Yeah I can see how that's going to be a consequence due to the differential induced by the angle of the bellcrank there's going to be with right rudder.

It definitely _is_ off, I agree, and could use fixing (apart from your mod which is brilliant ).

In my case, tho, I'm starting back up after 10+ years of flying full-scale planks, so I'm not going to be doing much more than hovering with a training gear on it for quite a while . So it's not going to matter much to me.

And by then I'll probably be building a 700E or something that doesn't have this problem.

I'll just see what kind of mood I'm in when I get to loctiting the tailcase; I might still end up flipping the grips just for grins...

LS

[ScotY]

Originally Posted by Jasmine2501

That is all theory. GO FLY THE EFFING THING, IT IS FINE!

And yes, I understand what people are saying, but to give a quick visual inspection and decide that it's such crap that you're willing to insult Jason Krause, without even flying the thing, is a little over the top. I don't think Jason's reputation is in jeopardy because of this design, due to the fact that it flies fine, and I don't know about you, but I can't really see the "flaw" when the thing is in the air.

Well, since you seem to head up the Jason Krause fan club, would you give him a call and find out exactly how he sets up his 450 Pro? I didn't need to look too deep since the tail slider/bellcrank seems pretty much like the earlier Align 450s that I can remember. Aside from different tail blades, it's not a whole lot different. And while you have him on the phone, can you see if he can talk Align into putting out some revised parts?

I'm just calling it as I see it...it's a design flaw. If it insults your friend, I'm sorry but that's not going to change my opinion. I'm sure I'm far from the first person who's had this thought. He's a pro...I'm confident he knows what he's doing and can handle a little criticism. I actually suspect he didn't overlook this problem but somehow the fix was never implemented.

Now here's a poke at you...you should back down with your attitude. This thread is all about theory and setup. Why are you telling me to stop talking theory and go and fly it? I already know how it flies and it's a nice little model.

[lucien]

In case anyone's interested, I just got through with the tail build at this point and i did end up flipping the grips as Bob suggested. I looked at it both ways with the blades fitted and it's actually a lot better with the flip mod. So just confirms Bob is right (tho clearly he is just from watching the video). I think it really will come out better overall this way....

Onto putting the head in and adjusting all that...

LS

[muscleflex]

i just got a 450 pro. on the tail build now. do i need to do this flip mod?
i did check and the pitch on the tail is indeed 0 when the arm is at 90 degrees

if i dont do this flip mode, does it mean i wont be able to fly in rate mode?

[Bob O]

Originally Posted by muscleflex

i just got a 450 pro. on the tail build now. do i need to do this flip mod?
i did check and the pitch on the tail is indeed 0 when the arm is at 90 degrees

if i dont do this flip mode, does it mean i wont be able to fly in rate mode?

If you get zero degrees of pitch with the tail slider centered, then there's no need to flip the grips as you will still have zero degrees.

If you have the slider centered but DO have pitch in the blades, you want to make sure its right rudder pitch.

[muscleflex]

Originally Posted by Bob O

If you get zero degrees of pitch with the tail slider centered, then there's no need to flip the grips as you will still have zero degrees.

If you have the slider centered but DO have pitch in the blades, you want to make sure its right rudder pitch.

you have just confused me now. i thought the whole reason for bob's tail mod was because the pitch is zero when tail arm is at 90degrees?! ie no counter action to the torque from the main blades hence, in theory, the heli will just spin around if pitch is 0 on the tail?

[lucien]

Originally Posted by muscleflex

you have just confused me now. i thought the whole reason for bob's tail mod was because the pitch is zero when tail arm is at 90degrees?! ie no counter action to the torque from the main blades hence, in theory, the heli will just spin around if pitch is 0 on the tail?

Sorry the confusion may be my fault. When I first got my kit yesterday I was just eyeballing the tailcase by itself and it didn't look that bad. So I got on and said "well it's not that bad".

But I did a u-turn once I had the blades fitted and the case temporarily fitted to the boom and I could see the situation more precisely. Then it was like... oh yeah, Bob's right, this tail is screwed up...

I'd say just rewatch his vid on the mod itself and his explanation of it. That's the clearest explanation of what the grip-flip does.

I just finished putting on the tail rudder servo and can see how much more linear the pitch range is with the tail with the grips flipped. Were it not for not having any dean connectors I could probably finish my build this weekend. Alas, it'll have to wait till I get connectors in the mail...

LS

[muscleflex]

exactly which video does it show what the problem is? i can't find it!
i have watched:
tailgyrostock
geometry
otherhelis

and there was no mention of what the problem is.
mymod video just shows what the mod is but no recap of what the problem is.


sorry if this has been asked before but it's a hassle going thru 88 pages of this thread.
oh and another thing - i can't really see how a servo doing an arc can have more range from 0 - 45 degrees than 45 - 90 degrees. a servo's arc should do a perfect circle if it is allowed to go around 360 degrees therefore distance between 0-45 and 45-90degrees is the same?!

EDIT: just found the problem video - arms at 90 and the pro gives positive pitch going with torque (should give REALLY fast piro then! )
i'll recheck my pro and see if i have the same problem.

[importfan]

I have a 450 Pro and have had the motor slide away from the main gear three times now. What is the correct install sequence. When watching the Finless videos the motor is not installed when doing the servo installation. Is it on another video that I missed. Seems I need the main gear in and then the motor and then work the servo install. Is this the best way? Also, do I need lockwashers on the motor screws? I have used loctite and tried to screw them in tight but they slip anyway. Thanks for any suggestions. The videos are great and I have learned a lot from the forums so I am hoping that hovering is only a couple of days away!