NX4 Stretched for 500mm blades?

[jaofos]

Originally Posted by akamullen

The SAB 500mm blades will work with the NX4 stock grips, you just need a brass insert to make the blade bolt hole go from 4mm to 3mm. The 500mm blades would be awesome IMO since they are very thin chorded for a 500mm blade. they are only 42mm wide, so about exactly the same chord width as most 420~470mm blades. once you go to 520ish blades, the blades are WAY wider and heavier, and will suck power from the engine pretty quick when flying any 3D.

Do you happen to know of any brass spacers? Surely someone out there makes some bolt hole spacers designed for something like this.

[jaofos]

This looks like it may work? Although it says blade root reducer, it has brass sleeves in it.

http://www.robsrchelispares.co.uk/PB...?ItmID=9492211

I can't believe how hard it is to find blade bolt reducers.

[jaofos]

I just got home and did some quick measurements on the X5 and the NX4 grips. As far as I can tell, the X5 grips will bolt right on and the spacing is identical between the two sets as far as link rods, etc. I'm going to hit the local hobby places this weekend and see if I can find some brass tubing. I also have a friend who just so happens to have a spare set of blades for his Goblin 500, so I'll borrow those as well. Now I just need the full length torque tube for the X5 and I should have everything I need to try 500mm blades on this guy.

[akamullen]

Originally Posted by jaofos

Do you happen to know of any brass spacers? Surely someone out there makes some bolt hole spacers designed for something like this.

The brass sleeves that come with EDGE 523 blades are almost exactly what you would need, they are a couple mm to long is the only thing, but could easily be cut with a dremel to the right length. they are 4mm outside dia. 3mm inside. I am sure there is a source somewhere out there, I have not really looked though.

[jaofos]

Originally Posted by akamullen

The brass sleeves that come with EDGE 523 blades are almost exactly what you would need, they are a couple mm to long is the only thing, but could easily be cut with a dremel to the right length. they are 4mm outside dia. 3mm inside. I am sure there is a source somewhere out there, I have not really looked though.

Thanks, I'll try to find some, if not I'll just order some X5 grips.

Think the NX4 will have issues swinging 500mm blades at 2700RPM? Doesn't look like there is an option to go down a pinion to lower headspeed for optimal motor RPM's.

[akamullen]

Originally Posted by jaofos

Thanks, I'll try to find some, if not I'll just order some X5 grips.

Think the NX4 will have issues swinging 500mm blades at 2700RPM? Doesn't look like there is an option to go down a pinion to lower headspeed for optimal motor RPM's.

Not sure, but I do know the SAB 500mm blades are VERY light weight for there length since they are the same width chord wise as most 425mm blades, so should not be a problem IMO, but I'm not a nitro guy so not positive, I would imagine they will be fine though. it would auto and fly very light weight, disc loading would be AWSOME as well! The 500's do come in a red version too, same blade with red accents, those would look pretty sweet on the NX4..

If you do try it, I am very interested in the results... Let us know how it goes...

[hoggy]

Interesting you guys want to use the sab 500mm I was using them on my goblin 500 and hated them I now use edge 473 and I find it flies way better just increased the headspeed a little to get the same pop but they track way better. The I had to tap out the brass sleeve in the edge 473 for the bolt to fit in.

[crickr1]

Originally Posted by jaofos

Would the X5 grips alter the head geometry in any way? I'm interested in attempting this, and not opposed to buying a set of X5 grips to try, if they don't work out I'll just have them as spares for the X5.

I may try fiddling with the grips tonight when I get home and see how the geometry compares between the two.

as far as I can tell, (and I remember nexgen over on the Hurricane forum swapped alot of these parts around. That's how I was influenced on my stretch.) they are same size and geometry. Just accommodate larger blades.

[bobbyra]

Originally Posted by jaofos

Well.. I may be trying this sooner than expected. I picked up a used (and already stretched!) NX4 by trading off my Goblin 500. Currently, the heli is running a cut-down X5 boom and torque tube, but I will be picking up a new X5 torque tube shaft and running the full length boom and TT, and giving it the carbon tail pushrod treatment using the Goblin 630 pushrod and X7 guide (the guides I have left over from doing this on my X5).

Really, the only thing I need to try the 500mm blades would be some brass inserts for the 3mm bolts on the NX4.

I'm looking forward to getting this little guy flying this weekend!

Here's a pic of her hangin in between the stretched Protos and the X5. A great addition to my fleet!

http://i.imgur.com/v1FxA1Ch.jpg

That is the best looking nx4 i have ever seen.

[jaofos]

Originally Posted by bobbyra

That is the best looking nx4 i have ever seen.

She had a great builder!

[jaofos]

How concerned should I be about balance going forward with this project? Right now, the SK540 seems to be handling the imbalance very well, I notice no negative tendencies in flight, piro's are flat and consistent, but that's no reason to completely ignore balance and just slap a bunch of extra weight on the tail.

Running some pretty heavy stuff up front with the 2600mah Duralite sentinel pack (110g) and regulator (50g or so). Not sure how much bigger I could go with an RX pack, surely not enough to make up the difference. Just a peek around Google didn't reveal any carbon fiber booms for the X5.

Just a couple of weight saving ideas for the stretched tail:
- Is the weight difference between the silver tail supports and carbon tail supports significant?
- Would the old style tail casing be a bit lighter than the "single piece" style?
- Carbon pushrod ( from Goblin 630 ) vs. stock
- Tail blades, runnin stock gaui carbon's, are there lighter options?
- Tail fin, the lynx vertical fin looks lighter? I'll nix the horizontal stab. as well.

Just tossing out ideas that pop in my head while I count down to my next parts order (Friday!).

[crickr1]

Older style tail is little lighter, my belt conversion is also lighter, no added bearings/gears.

[jaofos]

Originally Posted by crickr1

Older style tail is little lighter, my belt conversion is also lighter, no added bearings/gears.

I may swap them around. My X5 has the old style tail and is a bit nose-heavy with 12s packs.

[jaofos]

Mostly done! Waiting on the epoxy to cure on the new carbon tail control rod (cut down Goblin 630 carbon rod).

Looks like a Nitro X5!

Now I'm just debating running larger tail blades, or wondering if they are even needed. I have some spare 82mm KBDD's layin around.

[crickr1]

So you went with, x5 grips, Gob 500 blades and old style tail?
Looks pretty good, waiting on flight report........
Did you use Life? How's the CG?

[jaofos]

Originally Posted by crickr1

So you went with, x5 grips, Gob 500 blades and old style tail?
Looks pretty good, waiting on flight report........
Did you use Life? How's the CG?

Yeah I went with old style tail. It was 47g vs. 54g with new style, barely noticeable. I stuck a 2100 mah life pack (150g) up front (barely fits). I did some quick hovering and flips in the front yard, flies great so far.

CG? What's CG, lol! SK540 takes care of the CG for me, piro's are flat and stable.

[bobbyra]

So the x5 grips fit.If so i am putting 500mm blades on my x4II.

[akamullen]

Originally Posted by bobbyra

So the x5 grips fit.If so i am putting 500mm blades on my x4II.

NX4 and X4 II head is EXACTLY the same, only sold in different package with dif. part number.

[jaofos]

I can't imagine any way to get the CG right with any stretched version of this heli without adding tons of dead weight to the front. She's extremely tail heavy in this setup, so we'll see how she flies.

The 2 minute test flight in my front yard earlier didn't reveal any negative tendencies as a result of the CG (that I could tell). We'll see when I can get out to the field and fly a bit bigger and faster and get some video.

[akamullen]

Originally Posted by jaofos

I can't imagine any way to get the CG right with any stretched version of this heli without adding tons of dead weight to the front. She's extremely tail heavy in this setup, so we'll see how she flies.

The 2 minute test flight in my front yard earlier didn't reveal any negative tendencies as a result of the CG (that I could tell). We'll see when I can get out to the field and fly a bit bigger and faster and get some video.

Cant wait to hear how she flies!! If possible, get some video.. I bet it will auto FOREVER.....