help decide my my 425 stretch decisions

[wolveslayr]

After spending the week on other hobbies the Gaui got some attention.

My 425 Hurri will get some attention the coming week. The 8x12x3.5 bearing that slipped in its carrier resulting in complete deconstruction (bet Steve Jobs would have liked that description). I should have ordered it right away but being pound wise and penny conscious I waited till I figured all the bits I needed. I think a $6 pinion was $6 shipping. Don't like that when I need other undecided things.

SO, 1300kv~1350 Turnigy #3126 with a 14T, 15T pinion with a 550 long boom and 550 FRP blades gets me in the 1900 HS ballpark. Is that where I want to be? 1900? I've got Trex 600 skids, tail blades and flybar. Oh yea 85A Turnigy ESC switching, 2650 Rhino's, DX6i.

Oh, I know at one point the common wisdom was to get the 20T OWB due to 19T imperfections. Is that still the case or did GAUI make a better 19T in the last 12 months?

Am I covering every thing? Specifically the HS?

Thanks all,

Todd

[Jerrymac]

The 14T pinion mated to a 60T primary gear should get you in the ball park of around 1900, which is a good head speed for 550mm blades. I think I mentioned this in post #4, so I hope you also picked up a 60T primary gear.

The 50T primary( which comes with the 425 kit) mated to a 14T pinion will get you somewhere around 2200 to 2300, which is about right for 500mm blades, but might be a little too high for 550's. I run in the ball park of 1900 with 550's, 2300 with 500's, and about 2900 with 430's on my 3 different boomed Hurri's.

I have 'read' about incidents of the 19T OW gear cracking, but I have never had one crack. Of course, I have also read about many OWB failures too, but I have never experienced that yet either. Just sayin..........

One thing I have noticed on the many forums is that when someone has a part failure, all of a sudden it becomes a "known issue". The same single part failure will be mentioned hundreds of times in different threads, even it it only happened once, lol.
I once had a 325mm Align blade break off at the root on my BH450 causing the heli to self destruct, but, that certainly doesn't mean that all Align 325mm blades are junk. It was an isolated incident.

The one thing on the Hurri's that I myself have found to be a weak link are the bearings on the OW shaft. Due to their small size they seem to wear out prematurely. I had a noise in my 550 after about 70 flights and found those bearings seemed a little 'notchy' when rotating by hand. I had to replace them in my 425, which runs a higher head speed, after about 50 flights as they began making a noise too.

Oh, one more thing, flybar paddles. You didn't mention if you got the 550 paddles as they are much bigger than the stock 425 paddles. It will fly with the small 425 paddles, but the cyclic response will be pretty slow. I might have some spare 550 paddles here that I can send you if you need them, I will have to look through my many boxes of spare parts. I probably have some 60T primary gears here too if you need one. I have enough spare parts to start a Gaui Hurricane warehouse. ;D

It is a sickness, lol. Every time I need a couple of small parts, I place a $100 order to get the free shipping.

Jerry

[wolveslayr]

Sorry Jerry I should have reread the entire thread before asking my question. There were a lot of good tips given by very experience Gaui pilots.

I think the week away working on other projects combined with all the variables this heli can take form in many ways.

Speaking to myself here. Ultimately I want to fly 550 blades. I don't want to build it as a 425 when I came to understand how much stabilizer it would be for a novice to control the 550 blades.

So possibly a new lower kv motor, a pinon or 2, possibly a 20T OWB
Possibly a two small tail servo for a 550 boom (ino-lab D261HB).
Several pair of 550 FRP blades. Some 430 blades that probably won't be used a while.

Although explained well by those here. It put me in a stand still. One thing I have learned in RC is to have patience and not just rush a model before your ready.

I think one thing I was thrown by was somebody may say they flew their 550 (but their using 500 blades). So it was me assuming and not looking closer.

I guess it's pretty safe to say people with 550 booms fly 500 or 550 blades. Makes sense now.

Also, I was thinking the longer boom might give more tail authority. My understanding now is it's just to keep the tail out of the way of the blades.

I do have Align 600 paddles but they have the holes so I may get something heavier. I also have the Align Tail blades and will get a bigger fin. Haven't ordered my 60T or anything. I'm thinking nobody will have everything I need. So I just need to order from multiple vendors.

I'm not one to ask for parts. So thanks Jerry, dunkonu and others for their time. I'll get everything together and take my time.

Todd
The bearing that deconstructed was to support the OW shaft.
EDIT: Spent a couple hours on HF. In the past it seemed not much activity and some older information. I spent some time and dug 5-6 pages in and got a bit wiser.
I think building the 425 to a 500 with 470L blades or 500W. Is my best bet. Instead of trying to hit that ultimate goal right now is unreasonable. It's still way bigger than my 450.
Now except for the bearing. I'll pick up some spindles, shafts...a crash kit x 2. Get my lumps and come back for the X5 when $ allows.

Todd

[Jerrymac]

Todd,
I think the reason the '550' sometimes gets confusing is because the original 550 kits came with 500mm blades. Not sure why, but that is what mine came with too. Some people just built and flew them that way, while others, like me, installed 550mm blades.

You could use that motor with a 14T pinion and 50T primary and run 500mm blades. I guess it can just get a little more confusing when you are building a kit that has so many boom lengths and gearing options available.

I think you will find that the Hurri actually crashes pretty well, lol. I have been fortunate not to crash too often, but usually just end up damaging the blades and boom.

Sorry if I may have caused you more confusion than assistance. Just trying to help.

Jerry

[wolveslayr]

No you definitely helped me. I have spent more time reading here and HF today. At first I was thinking I may just build it the way I bought it.

On the other hand the boom kit is cheap. 500 woodies aren't breaking the bank.

Got the electronics, paddles flybar. Makes me (change my mind a lot) want to spend $40-50 and fly it bigger.

One thing I haven't at least come across yet is the inclusion when converting a 425 to a 550 is with the longer boom you need longer boom supports. Seems common sense.

The other is the crash kit. Those of us noob novices. A short 30 sec. first flight, new parts frustration can get a person out of the hobby.

Todd

[Jerrymac]

The boom supports ( G-204557 ) are the same for the 425 and 550. I know it would seem strange, but they were made for the 550 I believe. They just look a little bit long on the 425.

As far as I know, the only difference in the 425 and 550 air frame is the boom, belt, tail control rod, fly bar paddles, main blades, and tail blades. All of the other parts are the same for both. They also make a medium sized boom kit that can be used with 500mm blades instead of the long boom. ( More confusion, hehe )

So, basically, if you want to stretch the 425 to run 500mm blades, you can use either the medium boom kit, or long boom kit. You would need to gear for a head speed of somewhere around 2200 to 2400. Then just add a set of 500mm blades, and larger tail blades and fly bar paddles.

There is a lot of helpful info over on Freak, unfortunately, too much of it gets lost in the many hundreds of threads over there. That is one of the reasons we decided to put this site together. We were hoping that we would be able to organize some of the info to make it easier to find.

Don't worry too much about crashing 30 sec into your first hover. If you have your set up right, you will be surprised at just how stable a larger helicopter can be compared to a small 450 sized heli. Believe me, you will be like, WOW, ;D it practically hovers on it's own.

BTW, I don't remember you asking for any parts. I offered them, and the offer still stands if you need anything that I have on hand. Helping other RC hobbyists out is just another part of the hobby.

Jerry

[wolveslayr]

BTW, I don't remember you asking for any parts. I offered them, and the offer still stands if you need anything that I have on hand. Helping other RC hobbyists out is just another part of the hobby.

You didn't and I just don't want to take advantage of the good will shown me here.

If it was something I couldn't find and you were not going to use it, I'd be happy to pay.

I do have some unused 430 woodies from HFCenter. If I build the mid or long boom. I'll find somebody that might want them. If people don't help those starting. They probably won't continue. I learn from noobs almost daily.

Todd

[Jerrymac]

Sorry if I offended you in some way as it certainly wasn't my intentions. Was just trying to help out, that's all.

[wolveslayr]

I'm sorry if you got that impression. It was totally unintended.

Thanks for the work you do here and the Gaui community.

I'm about to start the build. The 550 manual helped a lot. Much clearer.

I may drive to a LHS today and look for a 12x8x3.5 bearings, seem common.

I checked Boca Bearings and the first one up was $16. World class yes, but I think $5-7 bearings should be fine.

Todd

[Jerrymac]

Wow, $16 for a bearing sounds a little excessive to me.

Gaui could have done a much better job with the 425 manual. Maybe just a reprint of the 550 manual with a few changes.

Good luck with your new build. Keep us updated on your progress.

Jerry

[dunkonu23]

Checkout either RCBearings or VXB Bearings. They're much less expensive.

Scott