Gaui 255 issues

[bobo14]

Hi guys,

so I've just finnished my Hurricane 255 super combo build and had my first test flight. I'm having a problem with the tail.

I fly in heading hold mode and have 32% true gain using my DX7s. with all the trims set to 0 the nose of the bird sways to the left (tail to the right). now i can trim it out but i can't seem to find a nice center point in the trim.

I have also read a few posts where people say it shouldn't drift at all in HH mode.

This is my first build so i'm not all that sure of what i should be looking for.

If anyone can help that would be great thanks.

[glarepro]

Do not trim out the rudder in Heading hold. Flip the switch into normal mode (rate mode) for your gyro and then hover. If the heli is drifting land and move your rudder servo in or out along the tail boom accordingly. Hover again. Repeat this process until you find center. After you find the range you can fine trim by screwing the pushrod link in or out. No need to trim the rudder at this point anymore. Once you've found neutral on your rudder you will have to re-establish the end points on your rudder. You dont want binding to occur because you moved the rudder servo. Once you find center in normal mode and re-establish your rudder end-points, you can fly in heading hold mode. From here on out you can play with the gain if you wish.

[bobo14]

thank you very much. that helps. is -32% true gain on my Dx7s a good setting for normal mode test hovering?

i have 1 more thing... when i power up in HH mode everything seems fine for a while but then the tail slider moves to an end poin (towards the boom). It does this on it's own without touching the bird or the radio. when i flip to normal mode it resets to center but then goes back to the end point when i flip back to HH. when i try to take off like this the bird spins like crazy.

I did have another tread asking the same thing and everyone said it was normal, I guess I'm just being a pain in the butt.

[rhodesengr]

not sure about the DX7 but on a DX6i a gyro gain of 32 is Rate Mode, not HH mode. You need to be above 50 to be in HH mode.

Just googled and found this:
The gyro gain setting in the DX7 ranges from 0% to 100%, with 50% being the reference value. When the value is below 50% the gyro is in rate mode, and the gain increases as the value is decreased. Values above 50% put the gyro in head-hold mode, and the gain increases as the value is increased. The DX8 values range from minus 100% to plus 100%, with zero being the reference. Positive values put the gyro in head-hold mode, while negative values put it in rate mode.

[bobo14]

yeah researched that too. The DX7(s) is the newer version which i have and it's like the DX8 (+100% to -100%). the old DX7 were like the DX6i.

[rhodesengr]

did you try just turning up the gain? My X2 was rotating slowly left until I turned up the gain. I've read that you should be just below where wag sets in. I am running the FBL with the AR7200BX so things might be different but maybe you just need more gain. I needed more gain when i dropped the pinion to 13T. This makes sense because the tail speed was also less so needed more pitch for a given amount or tail power.

[MinskUK]

I experience similar issues with my 255, a tendency to rotate counter clockwise on throttle input, whether up or down. Increasing the gain only resulted in wag. Even when I went FBL on this heli (BeastX) this particular downer remained. I decided I spent enough time trying to get this bird how I wanted, but never one to give in easily, Two week ago I replaced all the bundle Servo's with MKS parts - 3 DS92A on cyclic and a DS95i on Tail. This was a drastically expensive approach but my rational to my heli fund was that if it didn't work I'd have some very capable servo's for use in a future heli. I also read another thread where one of the Mikado developers had stated that fast servo's are the key stable small heli's. So far I've had 3 tests flights. The tail no longer moves of its own will, and the heil hovers hands off. Initially impressed and I'm optimistic that the small heil I was looking for may be starting to materialise. Hopefully if its not blowing a gale in the UK this weekend, I'll test (though really that should be enjoy) further . I'll keep you posted, but its finally looking promising albeit this heli is no longer the cheap flyer I'd intended - must start saving for that 300x...

[djelom]

HI MinskUK, me too had started with cheapy tail servo, but ended up upgrading since the tail seems to put quite some efforts on the servo.

Just out of curriosity, what's the weilght of your bird without battery?

Thanks

[MinskUK]

not sure what it was before, but the digital kitchen scales report 324 grams without battery or canopy.

[fusionsx00]

I would still keep this over the blade 300x, I have owened a blade sr and I did a belt mod with a Rex and then a gaui tail. The 300x is going to be a sr with a belt mod factory installed.

I've gone that road and no thank you, the one thing I know about High power heil like the 255/x2
Is they are attention leaches. If you dont pay them enough attention they act up. I have heard his from a gaui piloit , I agree the bearings and components are small and wear fast. But they fly so crazy good its worth the trouble.

Its just these smaller birds spin some serious head speeds, stuff wears out fast. The larger birds not as much. Just don't give up , they are well worth the effort and once you get them flying good the flights are amazing. And they run on cheap packs. Both of mine are waiting for a spartan vortex or msh brain. Till then they will sit idle.

[glarepro]

I'm loving my X2. I hope the bearings hold up.

[MinskUK]

I think you're right about the attention required on these smaller heli's. On my last rebuild which followed a 'what happened there event', as well as all MKS servers, I repositioned the BeastX to the front and replaced all the main shaft bearing. I think the later may have caused micro vibration which affected the BeastX. Anybody else experienced an unintended and uncontrolled roll? I also started from scratch on the BeastX and TX setup. Now, after this my first initial flight was unlike any previously experienced with this heli. I've not been able to test more as it hasn't stopped raining but it did appear to highlight the importance of setup and that even after a small 'ding', the head speed means that components can be potentially damaged even if they superficially appear OK.

Persisting with it thought as it now represents a significant investment - though the 300X thoughts were more about a backup heli that spends more time in the air than a replacement - a little like my MCPx does!

Thought the X2 its a commendable little Heil, there are always design improvements that could help us keep them in the air or get them back in the air quicker. Maybe one for a separate thread but to start the ball rolling - a request for a redesigned hub that the uses a nut and bolt rather than a screw!

[glarepro]

They should make the idler pulleys sit higher up somehow. Possibly by making the pulleys 40% shorter. This way we dont have to add O-rings that wear out real fast to keep the belt from rubbing the gears, or do away with a belt all together and design a nice TT tail. I'm sure Bobby can convert his tail design over to a torque tube. Also, make a slot in the tail boom that slips into the corresponding tab in the boom block to the frame. This way we know we always get a perfect 90 degress of perpendicularity on the tail shaft in relation to the Main Shaft. I hate having to stare one eyed down a boom for 30 mins trying to make sure its 90 degrees. Just put a perfect slot, slide it in, clamp down, and done. Other than those two minor gripes the GAUI X2 flys brilliantly with BEAST-X. It really does. GAUI has successfuly addressed all the other issues that plagued the 255 (ie. carbon landing gear, canopy stiffners etc..) when they released the X2. With the last two issues rectified as I stated (idler pulleys, and perpendicular tail configuration for dummies) it would be perfect. I LOVE my X2. I fly it almost everyday, sometimes twice a day. It flys like its on rails, it turns on a dime and it handles the wind really well too. Its a superb neighborhood flyer!
I was flying it for a friend on Sunday right in front of my house over the neighborhood street and the first thing out of his mouth was "DAM THAT THING IS NIMBLE!"

[desertstalker]

The slot is a good idea, but you wont see a TT tail.

It would likely be very fragile and would require a re-design of the frame. What they really need to do is correct the design of the belt system (better quality pulleys and as you stated, correct the idler pulley size. The belt it self is quite durable, but like most belts you should probably replace it every 1-200 flights.

[glarepro]

Had a good flying session today after work. I checked over my heli like I do after every flight and found out the tail bearing is coming out. I'm lucky it didnt come out during flight because today I was really pushing it. Here is the next thing I found out GAUI needs to do. They need to put bigger washers to hold the tail bearing in better. The washers they supply are the exact same size as the screw head and its not big enough to hold the tail bearing in. I dont have a washer that small. I'm not sure where I can get one.
I also see a shim that seemed to have gotten loose inbetween the pulley and the tail bearing,
and the brass bushing is coming out on the other side (tail slide hub side).
For now I'm grounded. I gotta take the tail apart and take a closer look...

[glarepro]

I went to my local hobbystore today looking for a washer that will fit that tiny screw yet still be big enough to hold the tail bearing in. He freakin laughed at me and said "Good luck finding that washer bud." He didnt give a crap because he doesnt get rich selling a pack of washers.

And to add insult to injury I just found out the tech over at GAUI aint gonna be back in untill monday.
Maybe Bobby Watts could help me out? It is his tail design after all.

Looks like my X2 is grounded for at least 5 more days. This really sucks big time man! I was hoping I could get at least 50 flights without a single issue. Oh well.

I'm back to the FURION 450 now...

[GravityJunkie]

I doubt you'd find anything locally for it, other than maybe a hobby shop. Get the hole size and the outside diameter you'd like and google it up. Or check bigger hobby sites with a good search engine. At least that's what I would do. Either way, you'll be down for a bit though.

[desertstalker]

Washer for the tail bearing farthest from tail blades?

Use a washer from the frame screws (the conical ones), they work well, they do overlap the bearing slightly but do no touch the inner race (cover the seal a little but that is recesses so no biggie). You could file it slightly if you wanted (they are very soft Al).

[glarepro]

Thanks for the tip. Yeah its the washers for the bearing farthest from the tail blades, and also the little brass bushing is coming out on the other side where the tail pitch slide is. What do I do to fix that? I tried just poping it back in before with a screwdriver but it just vibrated back out again.

[desertstalker]

Originally Posted by glarepro

also the little brass bushing is coming out on the other side where the tail pitch slide is. What do I do to fix that? I tried just poping it back in before with a screwdriver but it just vibrated back out again.

No idea, im not even sure what thats for.