New "Gazaur" build (re-build)

[praetorious]

Hey there,

Just a sanity check, your brushless is spinning right? Have you checked that the pinion is secured to the shaft?

If you recently reinstalled the OWB, it may be in upside down. This would cause the gear to spin with no joy at the rotor.

There is a small arrow on the top of the outer race of the OWB which tells you the direction of rotation. If memory serves, the marked side should be at the bottom of the main gear, and the unmarked side should be flush with the top surface of the main gear. You can do a sanity check by rotating the owb on the mainshaft and ensuring that it locks in the correct direction of rotation.

Now, if after ensuring your OWB is properly installed, and this problem persists, then your OWB has failed, and you will need to replace it.

Mars480.com at some point sold an owb removal/replacement tool, if they still have that you can pick it up along with a new OWB [you will also need a clamp]. I have one and it works well, but I use it just to remove the bearing.
To replace the bearing I use a tool I made consisting of a 10mm hex nut and bolt, and 2x of an assortment of washers. The bolt is put through the owb and main gear, then the washers on either side and then the nut. I then use a spanner and socket wrench to tighten the nut. This pushes the owb into the sleeve to the correct depth. It's also a good idea to use the dry lube on the outside of the owb and the inside of the sleeve.


For more info on OWB failure modes, and in particular why a faulty owb appears to work on the bench, check out this post:
https://www.helifreak.com/showpost.p...07&postcount=7

Good Luck, let me know how it goes.

Also, feel free to email Dave at mars480.com for help. If I'm online (skype or HF) you can pm/message me for direct help.

B.R.
Amit

[crickr1]

Thank you very much, very informative. As i said as a bone-head move on my part, but hey, at least no heli's got hurt! Now I know what I am looking for I can see the marking (DUH) on the old gear and owb.at least I have another set so I will assemble correctly this time.
I will also look for the removal tool@480 and order with my next parts order. Would like to get some air time this morning, have a lot to do with family today, and it is brutally HOT here in Jersey.
Hoping to be able to finally enjoy some air time with her.
Thank you for all your help,

Keep it in the air!

[praetorious]

That's great. You'll be back in the air soon. Just for future reference, I think Dave at Mars480 will install the OWB into your main gear if you ask him to, you'll have to check with him though.

[husafreak]

Hey, just checking the threads and glad to see you got the Poseidon airborne! Can't wait to see the trippy gold canopy :o) Note that the cutouts I made in the original were only necessary when ambient temps over 100 and hard flying started to heat things up. I found the Poseidon very stable in hover so check your links are free if you find it isn't so. The advice about big washers at the motor mount is good but that is why the motor mount plate is doubled up (for the same reason). Interesting that you found the "grabby" stock gear a challenge, I was an accomplished flyer by the time I got it going but with the stock legs it does not slide 1mm after the skids touch! I had the ESC above the battery right under the cutouts and the RX at the back lower frame. Use an appropriate size socket and drill press to push the one way in and out the main gear, works great. Good luck with the Poseidon!

[crickr1]

Couple of pics, need to get some better ones

[apollo7]

sweet!!

[praetorious]

That is great work crickr1! I love the paint scheme, it is the best I've seen on a Poseidon.
Why did you reverse your landing struts? Was it to gain more clearance or was it to get that Henseleit look?

Here's a photo of my motor mount with the added copper washers. i think this is must for increasing the longevity and serviceability of the mounts:



B.R.
Amit

[<3My480Pro]

thats an awesome idea praetorious ima do that to my mars. heres what i have to save the tail blades

[<3My480Pro]

we should have a hint and tips thread for our gazaur

[crickr1]

Thanks for all the tips and compliments! Feeling right at home already ,even as a newbie!

Praetorious, didn't realize gear was backwards LOL! Maybe thats why I thought it was so sticky on pavement!

I will get pics up soon of the paint I did on a Mars, I am going to do the mod on the motor mount this week. Stripped a few gears.

<3My480Pro is that some horizontal CF? How did you attach to tail?

Maybe this weekend I will get some more pics up,

Keep it in the air!

[<3My480Pro]

It's the vertical tail stabilizer parts number GPM0198 from mars480.com. It comes with a hole on the bottom of the fin so I went and cut a 2 inch fiber rod and CA it in. I don't know how the the tail blade sits on the poseidon but on the mars it spins pretty close to ground.

[crickr1]

Tail does sit close to ground on poseidon also. I stiffened the landing gear also with fiber rod and that picked tail up almost an inch. I think the Mars skids are stiffer then Poseidon. I am waiting on some new skids today.I have the GF and was also wondering if the CF has more rigidity. I may pick up a Mars CF kit soon (if I sell some good jobs soon).

Maybe we should all start a new "Show off your Gazaur pics" thread soon. Talking to some of my friends at the field and raising interest in Gazaur helis. Would be nice to see some more around but then again, I like having "Unique" stuff!

Keep it in the air!

[praetorious]

There are two show-off-your-Gazaur threads somewhere around here. They just fall to lower positions because there haven't been new picture posts. You can add yours to those threads if you find them and bring them right back up.

<3My480Pro That's a cool mod. I've seen people use rings attached to the stabilizer to protect the tail blades.

Yes, the tail rotor on both birds is close to the ground. This is because unlike in most birds, the belt drive is below the main gear. I suppose this was done(well the reason why I personally would do it) is to move the boom farther away from the blades, to minimize the chance of a boom strike.

I grew tired of nicking my stock tail blades, so I started buying the carbon fibre 59mm Radix tail blades from Mars480.com. I think they may be 2-3mm shorter than stock, so It gives a bit more clearance off the ground. Unfortunately if you drag the tail sideways on the ground, you will damage the CF ones too! It's not really a problem when you have more flights and experience under your belt.

And yes, the CF is stiffer than the GF. This is very apparent when you compare CF and GF Mars vertical stabilizers. The GF stabilizer in my experience, will begin to bend(especially if you did not set your tail gearbox flush :/) depending on how you set it down. And depending on how you store it, you may get a permanent curve.
I bought the GF kits because I loved the look of the silver fibre. But there is only a $20-something difference between a CF and GF kit, so go for the CF if you are so inclined! in fact, a cheap way to keep spares for these birds is to buy a whole other kit, so if you go that route, go for a CF one.

B.R.
Amit

[<3My480Pro]

thanks praetorious. also if u take a look at where the screw is on the vertical stabilizer, I added hard rubber o-rings to reduce tail vibration. no matter how well balanced the tail blade is, for some reason I get a really bad mid rpm vib on the rear end. adding the o-rings it completely reduce 80-90% tail vib at all rmp. only problem is tail case is not as secure as i would like it to be.

[praetorious]

Hey, yeah, I noticed the o-rings. good idea, but they will only alleviate a symptom of vibration, and not the vibration itself. The Gazaur landing gear and tail are particularly good at letting you know when something is off with your setup vibration wise. It's a left to right vibration right? If it is, then it's not your tail, but your head you need to check out. Particularly, the mounting of the head to the mainshaft. You need to make sure it is flush and the bolts are tight.

Read this quick thread I posted in about tail fin vibes:
https://www.helifreak.com/showthread.php?t=317644

There are other vibration tracking threads all over HF.

B.R.
Amit

[<3My480Pro]

actually i get the vibration switching from low rpm (hoover) to mid rpm (stunt 1). took out main blades and tail blades and have her spool up and it's smooth like butter. with cf main blades on it's still smooth. with balanced tail blades on it gets crazy at mid rmp. i've replaced all shaft to new ones and new tail blades still same thing. i was scratching my head for a while until i thought of the o-ring solution

[praetorious]

Have you replaced your feathering shaft?

[<3My480Pro]

yep first thing i replace after ever crash, light or severe. that thing is pretty weak. but it's better having to replace that than other things that might be more expensive .

[praetorious]

Odd. If I could see a video of your bird, I might be able to tell you what it is. I've just been flying it for that long.

The feathering shaft is interesting really. I think it is either 3 or 3.5mm diameter, most 450 birds use 4mm I think. So yes it always goes in a crash, especially if you have metal grips and CF blades, but otoh, it saves other parts when it does. In my last few bad crashes, the shaft snapped completely in two and my blades, by some miracle were saved.

[apollo7]

after checking the routine stuff ie: main blades balance, tracking, shafts, bearings, and still have tail vibrations @ high rpm its probally the hub connection to the shaft. If the gazaur has one drawback its where the shaft meets the hub. For every advantage (floating heads provide greater stability) theres a disadvantage (harder to keep balanced). Sissor type/bell hiller heads are easier to keep balanced but are less stable and can have cross coupling issues, and more slop.

Solution: loosen hub and re-seat. Sometimes I have left hub just a hair loose, spool up, and then tighten down hub (torque each screw a little at a time). If that don't work you can always add weight (i use black electrical tape) onto one of the main blades to counter weight the imperfect alignment of the connection of shaft to the hub.

If your hub has been damaged in a crash then of course it would need replaced. OR the main shaft collar could be damaged. Remember when heli was brand new? Chances are you didn't have this issue. That would signal theres been something damaged. I would guess the hub, or main shaft collar bent, or dented.