CX Swing Blades
 

Project Success!
I took the advise of several posts on here about the blade grip style mounts that the guys are making. I went with one more revision. Rather than a screw hole, I went oversized and used a #2-56 screw with a blind nut. There's a lousy photo attached for those who don't know what the blind nut looks like.
Anyhow, with the blind nut epoxied to the underside of the grip, the barrel protrudes through the grip and through the blade. The screw holds it all together. The blades actually swing, like on the big helis. It looks sort of pitiful sitting there with the blades all wopperjawed, but as I bring the rpm up slowly it settles into a perfect balance and hovers well.
I'd have never believed that the CX would run with swing blades, but it's happy as a helicopter has a right to be. Go figure!
There is a photo of the heli before I powered up, then the same photo with the blades at rpm nearly at liftoff. The stop action is blurry, but it shows the blades properly aligned and the center hub is running true. Note, I had to add 6 layers of tape to one of the upper blades to get a balance. I am using junk blades for this experiment.
Soloboss

RE: CX Swing Blades
 

So...does it really fly well?
How's the tracking and flight times?

Next Flight: Please fly into something hard, at a good pace, and let us know how the blades make out.

I'm going to need complete and detailed data in order to come to a conclusion on the desirability of this modification.

RE: CX Swing Blades
 

Thats a good idea, but I do have to wonder, why do that which might be more weight then just a normal locking nut? How is your other balance. the forward to backward setup. I havent had the time to look at mine yet. Anyway. It looks good. Glad you tried it out. Dont forget to post more tests :)

RE: CX Swing Blades
 

If I didn't already have my order in for the xtreme grips this would have been the mod for me. That last doosy of a crash kind of put things in perspective for me. I have quit the radical flying and now have 10 bats on the same set of blades. Another record for me as a pilot. Even my wife noticed something was up because I was spending more time in the air than on the repair bench! Great work as usual Soloboss, keep us posted on your findings!

RE: CX Swing Blades
 

Honestly, I was so excited to see the blades self-align that I wanted to post the preliminary details before bed. I did spin it up twice. The first time with the blades nearly aligned, the second time - well, you saw the photo.
So the early results are that it does fine. I was hovering in a confined area (about 4 x 4 feet) and it was controllable. I poked the sticks around and it seems to be tight. I expected it to be loose and sloppy.
I see that I have other replies so I'll catch those and everybody who cares can read all the stuff and we'll pick it up from there.

Oh, and I ended my little flight by crashing into the steel leg of my computer desk. It's a rectangular, hard edged leg and I whacked it a good one. No damage.

As I noted, the blades were out of the scrap bucket. Two of them had broken at the blade / mount boss juncture and were epoxied back together. One has a major chip in the leading edge with a tape band-aid. The one opposing the band-aid blade has 6 strips of packing tape, 3/8" x 2" to get static balance. And the thing flies with no shake.

Soloboss

RE: CX Swing Blades
 

Geez.........Now yer gonna make me follow your lead, as usual, like a curious little puppy.....I think this could work, I really do...I've seen even before a long time ago of someone else doing this, and been seeing it a few more times currently....Here is a web-site, and some pics that this gentleman took of also how he did it...I'am hoping yours is similiar Solo, as I take your word more assured, than possibly others...But it looks like the same concept...I'am sure Horizon has thought of this, but why would they do that, when they could keep the business flowing with blades breaking...Lol...(Job-Security)... I'am always getting something no matter what it is, and re-engineering it (hopefully) for a even better product, and this makes good sense, on at least giving it a shot...Thanks for the involuntary blade strike on the stool...:) That just shows me even more that I'll have to give this mod a shot..! Keep up the good work there Mr. Solo........... Jeff ;)



http://www.stingerrc.com/heli_articl...lade_CX_Titan/

I tried to download the pics, but there a bitmap image (whatever that is) but click on the link, and you'll see how he does this, if a new guy is wondering....:D

RE: CX Swing Blades
 

When I came home with the package, trimmed the contents to the configuration I needed. That was (4) each of screws -#2-56 x 1/2", flat washer and blind nut. The blind nuts are interesting. I cut the 3 pointed bits off so the flange would fit tight to the underside of the blade grip. If you look at the nut, there is no mass to them - the nut weighs 0.3 grams and the entire hardware pack per grip is 0.6 grams. I wish I had a scale that weighed to 2 places in grams, but I guess 0.6 is close enough for now.

Because the weight centered is on the shaft, it is in the center of the COG of the heli. My front to back and side to side movement seems to work well. But as I told Wolfpackin, this is really preliminary. First flights look excellent. And crashworthyness is at least as good as any blade grip because I have NO friction at the mount.

I went into the experiment was to make some use of the upper / lower blades that I cut to 1" shorter than stock. I made grips and tossed the rest.
Then I went through the blades that I should have thrown away, but didn't They are a sorry lot - the details are in my reply to Wolfpackin.

With the addition of the grips and the steel hardware, My heli dry weight is 183 grams. So I'm 4 grams above my standard weight.

My reason for the extra effort to get swinging blades comes from my Falcon. Every time I land hard or even spin up too quickly, one of the blades goes slightly out of alignment. I have read several accounts of blade grip users and they say they need to snug the blades somewhat. So, how do they align the blades? If they aren't nearly perfectly aligned with each other, the heli shakes terrible. Then they have to figure out if it's the upper or the lower rotor, then which blade is wrong. AARRGGHHHhhh! And it may be more than one. I don't need that missery - I'd rather buy blades. With my setup, I just swing the blades so they are pointed the right general direction and spin up slowly - just like a collective pitch.
Later I'll set up a camera and take a video of this thing spinning up.

So will this work better than the Xtreme grips? I doubt that something I made using a hand held Dremmel and no jigs for uniformity will outperform a CNC grip. On the other hand, perhaps the grip makers quit too soon in their design studio. These little buggers DO spin rotors fast enough to align the blades.

RE: CX Swing Blades
 

Here's the dope. Real Photos! How about that?
I guess the photos tell the story. Oh, and on the grips I left most of that gusset on the top side of the grip. When the blade starts to lift, it catches on the gusset and that keeps the lower blades from rising. That should be adding distance between the upper blades and lower blades to lessen blade clack. I took the gusset off the top grips so the blades will bend up under lift so the handling stays "normal".

I'm just wingin' it here, kids. Stay tuned as I learn more - or go get the hardware and do your own set. The hardware package was $1.39.

RE: CX Swing Blades
 

That's pretty cool, Solo.

I tried flying grips with them loose; and they line up alright, but when you go sliding side to side; they fold in the air! There must be a difference between a swing blade and a grip, right?

How is this different? Is the purpose for ALL grips, homemade or bought, is so that You can leave them loose. I was always told to tighten it.

Did You try hard aileron?

So the screw tightens on the blind nut before it tightens the blade, so it's secure without binding the blade, and the washer is just to keep excess play out of it?

Lots of questions. :)

Gary

RE: CX Swing Blades
 

I've heard of grips used on all of the larger helis. Collective pitch helis use them. I guess everything with a blade that has some mass to it uses them. My Falcon is odd in that I have to snug the blades. Really snug! I can turn them by hand, but they must be manually aligned. In the forum I've read far more accounts of CX guys tightening the blades on the grips. They leave enough movement that the blades will fold in a collision, but the blades are pretty snug in the grips. I only use the term Swing Blade to indicate that my blades are flopping all over when I carry the heli around.

Now that I've said that -PLEASE - blade grip guys let me / us know if you are putting enough friction into the grip that you can turn the rotor. Or are you running with the blades swinging on the pivot? Inquiring minds need to know. If I just "Invented" the same thing you are using - well at least it was fun.

I have not had the opportunity for an outside trial. It may fold up like a $2 lawn chair. Time will tell. And it raining and dark out now.
I have so many variable that even if it does fly it may be a bad idea. Heck, the crummy blades may be so far wrong that they bind on the pivots at speed and that's what makes it work! I dunno. Yet.

I'd hate for anyone to follow my lead and waste another set of blades. We went through that with the clipped blades. (And I'm not dne with that yet. My next chapter is "Clips on Grips)

On the other hand, if you try it, it only works if you bring the rpm up slowly like the collective pitch guys do.

RE: CX Swing Blades
 

Solo;

I have to have them pretty tight, or in tight aileron, they buckle and the heli dives in. I have them so I can pretty much rotate them with a finger with no movement on the blade.

I only align them once loose, then tighten, test fly, and if no TBE, then mark the trailing edge of the blade and the corresponding area of the grip for realignment when I crash, so I don't have to untighten, rev, tighten again. Saves alot of time and wear on the screw.

I would try heavy aileron sliding the chopper side to side and that'll test Your swingblades. Let me know, You have my attention.



Gary

RE: CX Swing Blades
 

I use my setup pretty snug. It folds fine if I hit something but they are tight where they dont flop around any. They will after I get it up to speed straighten out on their own. I dont ever just mash the stick forward and wait for lift off. I always spin up the blades to ge them rotating a good speed. Then I mash both sticks forward and watch it go. Im waiting for G4 to come out so I can start working on my trex flying. I have noticed that even the electrics you spin them up slowly and then powerup to get lift. Maybe this needs to be something we do with the CX? I dont know. Solo, keep testing. IF it will work with them looser like the bigger helis. Ill go that route. Although I think the wind will have something to with it.

RE: CX Swing Blades
 

Holy Crap ! !

I just loosened up the grips real good on the XTREME'S and it flys GREAT ! !

I tried it with the Micro Heli Grips and it wouldn't work at all, OR maybe it's the XTREME blades that make it work, I don't know.

I just assumed that there wasn't enough blade Mass when it didn't work the first time.

I'm gonna leave them loose and loc tite the screws.

This is weird. I'm sure gonna enjoy them more!

RE: CX Swing Blades
 

Hey, Solo.

I haven't had a chance to test the flybar grommet mod. cause I just got my heli rebuilt and it's so pretty. I'm getting this canopy cutting stuff down to an Artform. I'm savoring it before I slam it around too much again testing things. Also, it lets me see how it handles right now and burns it to memory.

Jeff,

I took a hard one off the doorway, went crazy and and hit the floor; not even a scratch on a blade.

I think these grips are gonna pay for themselves. If this were weightwatchers, then I failed, cause the heli is 9 Grams over stock right now. I do love outdoor flying; maybe with the batts I have now, it'll be more forgiving with the added weight, but flight times should be the same as I'm finding out in the living room. Just can't find a calm day this time of year. The stock motors are doing fine, but I am conscious of the temperatures.

Gary

RE: CX Swing Blades
 

Gary,

Are you using the heatsink? I forgot.

RE: CX Swing Blades
 

Gary, I might have to give em' a shot here in the near future... Looking forward to some updates via outside flights.....Oh, Keep the CA glue away from them, I've read somewhere on here the two don't mix together very well....:)

RE: CX Swing Blades
 

Gary, thanks for posting about the xtremes. That might be what DR. ordered then if our homeade ones dont hold up. I am curious to know how it will work in outdoor flight though. With a little breeze, can they hold true and keep the bird in the air?

Oh. I agree with Jeff, Watch that CA :D

RE: CX Swing Blades
 

Yea, all aluminum now, including a heatsink on stock motors.

Gary.

Yea, I hear You on the outside flying. If it is a problem, then one could tighten them like I was flying originally and unwittingly.

I tried my best to fold the blades in flight doing some extreme manuevers in which my 22c batteries let me do some crazy stuff, without the altitude loss, rapid start and stop, backwards, forwards, sideways, sliding turns, uncoordinated turns and flew it under an active air conditioning vent in the basement. It did great, so I'm hoping that a little breeze won't affect it much. I tried this with the blades slightly tighter than a wet noodle flopping around. Tight enough that You align the blades relatively straight before spooling up, but loose enough that if You tried turning the rotor with a finger on the blade, the blade will fold. The neat things about the assembly, is that it has a 'stop' so the blades can't go too far forward, only back. So when You go to the stop, they are aligned good enough to start with, and the centrifigal force does the rest.

Gary

RE: CX Swing Blades
 

I can proudly say that I Used the extra thin CA for mounting a spotlight and nylon mesh on my canopy without incident. :)


BTW: during all the crazy manuevers I was doing, I crashed hard into the brick fireplace with blades almost at full throttle; it made a 'clackity' sound hitting the brick that protrudes out to hold the wooden mantle, before coming down. I just knew that I had damage; but absolutely none except some of the gray primer paint rubbed off the edge of the blades; no divets, dents, cracks; I was amazed, and the modified flybar received no damage either.

This is getting good! !

Gary

RE: CX Swing Blades
 

on the cp and fp i keep the blades loose enough to fold with a finger, but on these heavier blades you have to kinda align the blades so the heli doesn't flop around ot get too much wiggle until they get spun up enough

just pull hard on the ends and it should align fairly well - blade attachment test too


edge

RE: CX Swing Blades
 

Here in the heartland of America (aka flyover country) We still have green. And the green stuff still gets in the way. But I gotta love the blade grips. I untangled the heli and dropped it in the grass, spun up the rotors for alignment and flew again - in to the bush. Then the Cherry Tree. It just kept falling out of the trees and flying again. Since the blades fold up, it doesn't get stuck. Well, it was pretty stuck in the little tree in the photo. That poor dwarf pear tree. Worthless - and in the way.

Anyhow, he heli is fine with Full throttle fast forward rudder turns and aileron turns and uncoordinated turns. I also loops spins and power dives perfectly. Now what? I suppose you don't believe that. Have it your way. I have the grips so loose I get blade clack if I try to spin up the lower rotor first. The bottom blades hit the droopy upper blades!
This is a BLAST!! Fast forward is way faster than before.

Depending where I drill the hole relative to the spine on top of the grip (my home-made grip) I can get more pitch from the blades. I drill the hole just behind the spine (as the rotor turns, so the blade is tilted a bit to add pitch. Another variable - too much fun!

My intent with this blind nut hardware was for the nut to stick all the way through both blades so the blades would pivot with the screws tight. Didn't work. The nut is too short. I'm going to look into sex screws and that will give me large heads that don't need washers and with the screw and nut tight, the blades will swing easily.Never mind, they start at 3/16" diameter. That's not gonna work. I'll look at plastic screws and nuts now that I know this works.

ONWARD!!

Soloboss

RE: CX Swing Blades
 

Impressive results!

RE: CX Swing Blades
 

You asked me to test it rigorously.
Are ya satisfied?

LMAO
Soloboss

RE: CX Swing Blades
 

Eh........Seems the bigger trees are teaching the smaller ones how to reach out and grab our heli's....I guess size doesn't matter.......Lol..

RE: CX Swing Blades
 

YES