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HelicopterMain Discussion › Here's How To Make a set of blades out of two single ones (crash survivals)
11-26-2007 08:01 PM  9 years agoPost 41
JuanRodriguez

rrProfessor

The Villages, Florida

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How about AirWolfRC's suggestion from another post ??

Do a search and you'll find reams written about this topic.

There are hard ways to do this and there are easy ways to do this.

I choose the easy way (that still works)

Two steps are all that's needed.

6. Join the blades together at the root on a spindle and place the spindle on the edges of two glasses on a flat surface to create a see-saw.
7. Add tape to the lighter blade (at the tip)

You're done
Just another "method" for those not willing to drill into the blades at all.....

Above quote is from this thread :

http://www.runryder.com/helicopter/t385152p1/

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11-26-2007 09:26 PM  9 years agoPost 42
switch26

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San Jose

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JuanRodriguez
thats a good idea but you still have to balance the cg to the heavier blades,puting the two blades on a spindle is ok but you need to make sure the blades are not going to move while they're swinging up and down,this is why you would need a balancer,

it doesnt have to be and expensive balancer as long as it does the job,also the tape is used only when the blades are not too far apart something like a gram or so where the tape would do the job,but if it is off by say about 5 grams then you do need more than just tape

i've read that trhead and it is pretty interesting and informative
i wouldnt recoment balancing blades that are too far apart like say over 5 grams,you'd be in bad shape if you have to put too much weight also try not to put the weight too far away from the root,

the farther away from the root the more sentrifugal force at the tip,comon sence,right?

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11-27-2007 04:43 AM  9 years agoPost 43
Buzzin Brian

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College Station, Texas

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Switch26,

I understand you saying it has worked for years for you, but I have to point out that this is all comes down to the guy doing the modifications interpretation of the method and his level of understanding of the procedure. THIS leaves a LOT of grey area!!!! I could not TELL you how many times I have seen things done on helicopters over the years that I was like "who would even THINK to do such a thing". And most of those guys I would NOT want making their own blades, or drilling holes in them for that matter. I do not doubt your skill level, or your experience with this procedure, but the guy trying this might not have the same results for any number of unforeseen reasons. So I 100% agree, DO THIS AT YOUR OWN RISK!!!!

Build it, fly it, crash it. Repeat as often as needed.

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11-27-2007 12:40 PM  9 years agoPost 44
helifundi

rrNovice

Lick Run, PA

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Thanks for your excellent instructions Switch26. I have two mis-matched blades on the shelf now, and you just saved my $75.00! Your procedure is so simple and logical I can't believe I never figured it out myself. Thanks for your time and effort. RunRyder to the rescue.

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11-27-2007 11:28 PM  9 years agoPost 45
A. Gordon

rrApprentice

Farnham,Va.-USA

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switch26- Thanks for taking the time to post ths very usefull information. It is better to have explanation, rather than imagination when it comes to heli's and as said before "Do this at your own risk". Check over your blades thoroughly and if there is any doubt toss them out.

All for the spectators!!

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11-28-2007 01:33 AM  9 years agoPost 46
RappyTappy

rrProfessor

North Denver, Colorado

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A while back I was flying my Raptor 50 with some v's and doing some of that wizbang 3D and when I did a close fly by, I noticed my heli was shaking badly, looked like the dreaded woof and poof issue all over again. I landed checked everything and it all looked ok. Went to hover it again and I could barely lift off as it looked like it was going to blow up.
While I was checking over everything, I found that the weight had flown out of the hole that v-blade drilled which of course caused the blades to be very badly out of balance.
Even after this, I don't really see an issue with drilling into the blade a little and then inserting some weight, as long as its done properly, but as they say $hit happens and everyones mechanical skill level and expertise varies so ya never know I guess.

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11-28-2007 01:53 AM  9 years agoPost 47
jking

rrApprentice

artesia,new mexico

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switch26 thanks for the info.sounds like you have really done your homework here and any manufacture will tell you not to do it because of liability reasons,and you wont be purchasing new as frequently heck that puts damper on income.

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11-28-2007 05:08 AM  9 years agoPost 48
switch26

rrKey Veteran

San Jose

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helifundi
im happy to hear that Bud,now you can just keep your old single blades and put them in the air again,im willing to match any blades for a fair price but you need to figure out if it is worth it for you since you'll be paying the shipping both ways,

A. Gordon
Thanks for the kind words,i hope this is usefull to everyone and save some cash,i wish i could do more for the heli comunity unfortunatly this takes time and some times your eforts are not appreciated,

this was posted long ago and i have had alot of people pming me about this so this is why i keep bumping it to the top
it is good info as long as you know what you're doing

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11-28-2007 05:17 AM  9 years agoPost 49
switch26

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San Jose

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just a side note:

when i started flying helis i started with a 30 size shuttleZ,back then the crash parts wer a bit too expencive for my taste,so i wanted to learn to make my own blades,

i then came across a good friend of mine who knew how to make them,so i asked him to teach me,so some of this i actually owe to him,good ol Mikey Crawley,he was good at flying just about anything,

and he used to make his own fiberglass gliders from scratch,he's still around but just lost contact with him

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11-29-2007 07:02 AM  9 years agoPost 50
bubba01

rrApprentice

NE Pennsylvania

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Thanks Switch26 for an easy fix!

I tried your method tonight and am happy to say it worked on 2 blades very well since they were close to the same weight.

The other pair I was going to try it on won't work though. I never really noticed how much the weight of identical brand blades varies before (since I never tried to salvage singles). But I have 2 Align 325 carbon fiber blades that I got with a used heli and knew they were mismatched....I just didn't know how much until tonight. The spanwise CG is within 1mm on the blades, but the weight difference is huge. How huge?....on the Koll Rotor Pro, it takes 4 3x8x4mm (Trex main grip) bearings placed at the spanwise CG to bring the blades into balance! I guess these 2 blades will sit on the shelf awhile longer till I get some more singles.


Cop: Sir, have you been drinking? Driver: Why? Is there a fat girl in my backseat?

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11-29-2007 11:24 AM  9 years agoPost 51
switch26

rrKey Veteran

San Jose

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bubba01
great,the cg is not so very critical it can be off say about 2mm and still fly good but preferably the cg would have to be dead on if you can,as far as the other blades being too far apart in weight,i think you are doing the right thing,just wait till another comes along,and just a reminder,try not to put the extra weight too far into the tip of the blade,im glad you got it done
Regards
Raf

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11-29-2007 11:40 AM  9 years agoPost 52
Jeff polisena

rrElite Veteran

westpalmbeachflorida usa

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for those people that are picky add a drop or two of black food color to jb weld when mixing to make it black so it doesnt stick out

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11-29-2007 12:07 PM  9 years agoPost 53
Hamo

rrVeteran

Ireland

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After reading so many conflicting views on blade balancing, I decided to do some testing. At first I was sceptical about AirWolf's simple two step method, so I tested it. I have a set of wooden blades so badly matched that the CGs are nearly half an inch apart. First I balanced these blades with the old, hard way, finding the lighter blade, adding tape to shift its CG to the same place as the heavier blade etc, etc.
I ended up with about 15 turns of 2 inch wide scotch tape at the tip of the lighter blade and about 8 turns of the same tape at the CG of the other blade. I flew the helicopter with these blades with no problems, no vibration while hovering, climbing, descending. Perfect.
Then I removed all the tape and balanced the same blades using the simple 2 step method. Bolt the blades at the root to create a see-saw and just add tape at the tip of the lighter blade (the one that's higher up) until they teeter. This way I only needed 4 turns of tape on one blade only. I flew the helicopter again and it flew without any problems. Same as before. To be sure I removed all the tape from the blades and repeated the above test a second time. Again, the result was the same. I think this proves that both methods work. When balancing blades, the CGs don't need to be matched, and the gram weight of the blades is not important. Please don't write to me with your theories or with what you heard from other people. Try it
yourself. Speak from experience.
Hamo

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11-30-2007 07:11 AM  9 years agoPost 54
switch26

rrKey Veteran

San Jose

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very good info Hamo,im sure the blades work since you already tryed it,im not going to debate your experiment but the reason the cg needs to be matched is simply because there will be more centrifugal force on the blade that has more weight towards the tip,

something to do with phisics,try holding 10 pounds on your hand bent at the elbow close to your sholder,now try holding the same 10 pounds but this time streach out your arm,you know what i mean?this is why it is important to match the cg

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11-30-2007 08:22 AM  9 years agoPost 55
Hamo

rrVeteran

Ireland

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No it's not. An adult and a child can balance on a see-saw simply by the adult sitting more forward. In this case the two sides of the see-saw have different weights and different CGs but the see-saw is balanced.
You can spin the see saw without any problems. Of course at high speed, the adult being bigger, will have more air resistance but that's another matter. Therefore the only important thing is that the blades teeter ie have the same moment. The actual gram weight and the CG positions don't seem to matter.
Hamo

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11-30-2007 01:02 PM  9 years agoPost 56
kangarooster

rrApprentice

Orlando Fl-USA

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Different spanwise CG's will cause each blade to have a different coning angle and will put side force on the mainshaft and bearings.
Not a good thing.
With small differences in CG's these problems may not be apparent,
but the are still there.

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11-30-2007 01:20 PM  9 years agoPost 57
Frank Bostwick

rrElite Veteran

Cincinnati Ohio

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And the balance wars continue

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11-30-2007 02:00 PM  9 years agoPost 58
Hamo

rrVeteran

Ireland

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Kangarooster, the blades I did my test with had their CGs about half an inch apart to start with, so what do you mean by small difference in CG. I added tape at the tip of the blade which was higher up till I got them to teeter. Then I flew the helicopter with these blades, there was no vibration, no problem. If the coning angles were very different this would surely cause visible vibration.
Hamo

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11-30-2007 02:49 PM  9 years agoPost 59
Hamo

rrVeteran

Ireland

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If the coning angles were different, would this not show up as blades going out of track while flying ?
Hamo

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11-30-2007 03:12 PM  9 years agoPost 60
kangarooster

rrApprentice

Orlando Fl-USA

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HAMO,With ridgid CF blades I have created 2 degree coning angle change with a CG movement of 1/2 " at a 60 percent distance on the blade span. definately flyable and with no serious effects.
Much of my balancing experience comes from trying to solve problems on my 5 bladed rotor which seems to have smaller tolerances.
My test setup consisted of a rotor head mounted on an adjustable bracket driven with a variable speed electric motor.
The blades had had modified laser pointer mounted pointing outward
and another was attached to the mainshaft pointing upwards.
I feel that I was able to ge accurate,repeatable results.
I use a different method and different tolerences when I balance ,
I wouldn't say one method was better than another,different situations lend themselves to different solutions.

Ben

Yes, tracking will change with RPM changes

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Scorpion Power Scorpion Power
HelicopterMain Discussion › Here's How To Make a set of blades out of two single ones (crash survivals)
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