MonsterMaxx
06-03-2007, 01:31 PM
I’m a total newbie flyer and have been enjoying the E-flite Blade CX2 micro helicopter since I got it 6 days ago. As I’ve gotten a little more adventurous on the sticks and moved the linkage out on the servo horns I found I got a lot of blade strikes. Both between upper and lower blades and the lower and flybar. Normally resulting in a crash and damaged blades.
So I thought, why not increase the separation between them and give it a little more room. I know this isn’t an original idea and there are products on the market to do this, but I’m kinda a do-it-yourself type and figured give it a shot.
I’ve also found the inner shaft is made from peanut butter metal and bends very easily so I figured I’d make that from music wire which is stronger. If it works out, I’ll order some drill rod (very strong) for the next try.
I figure that I’ll use a short piece of outer mainshaft from a damaged one I had and put a sleeve over the outside, then make a longer inner shaft.
I decided to try 15mm extended to see how that worked.
The result is zero blade strikes even with the most violent banging of the sticks. 15mm may be more than is needed, you should experiment on your own to find the optimal length.
Here’s how I did it:
I got some Ø.078” music wire from my LHS, $2.19
And some Ø 3/16” x .014 Aluminum tube, $2.19
To start I cut a 15mm long section of outer main shaft from a damaged one I had (chewed gear teeth.)
http://www.unlimitedengineering.com/gallery/files/1/CutShaft.jpg
Put the upper bearing on that 15mm section and butted it up against the new outer I’d installed in the frame and measured how long the Ø3/16” sleeve should be.
http://www.unlimitedengineering.com/gallery/files/1/TubeLength.jpg
(sorry for the fuzzy pic, camera got out of macro and I didn’t catch it.)
Then I cut some of the sleeve to 35.5mm and slipped it together for a test fit. Seemed good so I put a dot of CA on the outer shaft and slid things back together rotating them around to distribute the CA. The CA doesn’t really bind it together, but it does take up any slack. It can still be disassembled if needed to service the lower parts.
The next step would require the metal head’d inner shaft (I already had.) This is a good investment anyway since the stock plastic head seems to break pretty easily.
Deburr one end of the music wire and slip it up in the head. Install the setscrew and tighten it – this will mark the spot on the shaft you need to grind a small flat. Remove from the had and grind a small flat – cutoff wheel on the dremel works well for this.
http://www.unlimitedengineering.com/gallery/files/1/InnerShaftUpperNotch.jpg
Next is to assemble the whole thing so you can establish where the bottom marks need to be. Since you are still working with a long piece of music wire work from the underside of the bird, slip the music wire up thru the bottom gear, thru the bearing, up thru the outer shaft, into the head and install the setscrew ensuring you engage the flat. Now push the head down and the gear up taking out all the slack. Tighten the gear screws (this will mark the shaft) and mark the shaft where it sticks out of the gear. Dissassemble.
Grind two flats where the marks are and cut the shaft to length. I found that reinstalling the upper head and using the blades as reference helped get the flats 180° opposite each other.
http://www.unlimitedengineering.com/gallery/files/1/InnerShaftLowerNotch.jpg
I’ve found what seems to be a little misalignment between the pinion and the lower gear allowing it to chew half the teeth off. There seems to be a little flashing on the underside of the gear where it contacts the bearing, trim this off if you are using a new gear – check it at least.
http://www.unlimitedengineering.com/gallery/files/1/MainGear.jpg
Put everything back together and that’s about it.
http://www.unlimitedengineering.com/gallery/files/1/Finished.jpg
I found that 15mm was plenty to ensure that the lowers do not strike the uppers or the flybar no matter how hard I bang the sticks. I have my servo horns on the #3 hole for elevator and #2 on aleron which pretty well maximizes what the swash plate is capable of moving.
It seemed like the bird flew a little differently, though it was a bit gusty yesterday when I tried this and have already gotten used to it so I can’t really tell for sure if it made any difference in the way it flies. On the plus side I’m not shattering blades from strikes and crashing due to wacked out flybars.
I also just had the very first flight where I had no crashes on a whole pack, my brain is beginning to get the orientation down. I’m pleased with the results of $4.50 and 15 minutes of my time.
I’m sure others have done this before, but I didn’t see a thread on it or a how-to so I thought I’d share.
Hope you enjoy.
So I thought, why not increase the separation between them and give it a little more room. I know this isn’t an original idea and there are products on the market to do this, but I’m kinda a do-it-yourself type and figured give it a shot.
I’ve also found the inner shaft is made from peanut butter metal and bends very easily so I figured I’d make that from music wire which is stronger. If it works out, I’ll order some drill rod (very strong) for the next try.
I figure that I’ll use a short piece of outer mainshaft from a damaged one I had and put a sleeve over the outside, then make a longer inner shaft.
I decided to try 15mm extended to see how that worked.
The result is zero blade strikes even with the most violent banging of the sticks. 15mm may be more than is needed, you should experiment on your own to find the optimal length.
Here’s how I did it:
I got some Ø.078” music wire from my LHS, $2.19
And some Ø 3/16” x .014 Aluminum tube, $2.19
To start I cut a 15mm long section of outer main shaft from a damaged one I had (chewed gear teeth.)
http://www.unlimitedengineering.com/gallery/files/1/CutShaft.jpg
Put the upper bearing on that 15mm section and butted it up against the new outer I’d installed in the frame and measured how long the Ø3/16” sleeve should be.
http://www.unlimitedengineering.com/gallery/files/1/TubeLength.jpg
(sorry for the fuzzy pic, camera got out of macro and I didn’t catch it.)
Then I cut some of the sleeve to 35.5mm and slipped it together for a test fit. Seemed good so I put a dot of CA on the outer shaft and slid things back together rotating them around to distribute the CA. The CA doesn’t really bind it together, but it does take up any slack. It can still be disassembled if needed to service the lower parts.
The next step would require the metal head’d inner shaft (I already had.) This is a good investment anyway since the stock plastic head seems to break pretty easily.
Deburr one end of the music wire and slip it up in the head. Install the setscrew and tighten it – this will mark the spot on the shaft you need to grind a small flat. Remove from the had and grind a small flat – cutoff wheel on the dremel works well for this.
http://www.unlimitedengineering.com/gallery/files/1/InnerShaftUpperNotch.jpg
Next is to assemble the whole thing so you can establish where the bottom marks need to be. Since you are still working with a long piece of music wire work from the underside of the bird, slip the music wire up thru the bottom gear, thru the bearing, up thru the outer shaft, into the head and install the setscrew ensuring you engage the flat. Now push the head down and the gear up taking out all the slack. Tighten the gear screws (this will mark the shaft) and mark the shaft where it sticks out of the gear. Dissassemble.
Grind two flats where the marks are and cut the shaft to length. I found that reinstalling the upper head and using the blades as reference helped get the flats 180° opposite each other.
http://www.unlimitedengineering.com/gallery/files/1/InnerShaftLowerNotch.jpg
I’ve found what seems to be a little misalignment between the pinion and the lower gear allowing it to chew half the teeth off. There seems to be a little flashing on the underside of the gear where it contacts the bearing, trim this off if you are using a new gear – check it at least.
http://www.unlimitedengineering.com/gallery/files/1/MainGear.jpg
Put everything back together and that’s about it.
http://www.unlimitedengineering.com/gallery/files/1/Finished.jpg
I found that 15mm was plenty to ensure that the lowers do not strike the uppers or the flybar no matter how hard I bang the sticks. I have my servo horns on the #3 hole for elevator and #2 on aleron which pretty well maximizes what the swash plate is capable of moving.
It seemed like the bird flew a little differently, though it was a bit gusty yesterday when I tried this and have already gotten used to it so I can’t really tell for sure if it made any difference in the way it flies. On the plus side I’m not shattering blades from strikes and crashing due to wacked out flybars.
I also just had the very first flight where I had no crashes on a whole pack, my brain is beginning to get the orientation down. I’m pleased with the results of $4.50 and 15 minutes of my time.
I’m sure others have done this before, but I didn’t see a thread on it or a how-to so I thought I’d share.
Hope you enjoy.