Staff
Senior Member
Posts: 1510
Loc: Roanoke Va USA
Reg: 03-05-00
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 04-22-02 01:31 AM - Post#7093
Place your "Main & Tail Rotor Tips" on this thread!
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rotorwash
New Member
Posts: 11
Loc: Christiana, Tn.
Reg: 04-07-02
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04-22-02 11:58 PM - Post#7175
In response to Staff
Don't underestimate the importance of balancing the main rotor blades with a blade balancer. When I built my helicopter I didn't have one so I balanced the whole rotorhead assembly on a high-point & put tape at the end of the light blade. That was all I did & things seemed smooth enough. Recently though, I ordered a blade balancer & balanced each blade individually to make sure the CGs were the same & then balanced them together, adding tape to the CG of the light blade. What a difference! The rotorhead is much smoother now & it definitely flies better.
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Heli-Nut50
Member
Posts: 45
Loc: Valemount, BC, Canada
Reg: 03-15-02
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04-23-02 01:35 AM - Post#7186
In response to Staff
Keep that tracking. Whenever you perform maintence on you heli the main rotor blades usually come off so here is a very little thing you can do to keep things matched up. Just put a small dot of paint on one grip, its blade and pitch link this way you can have the rotor head right off and every thing is coded so when it goes back together it should all be the same as when you started.
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nsacco
Senior Member
Posts: 453
Loc: Raleigh, NC, USA
Reg: 01-10-01
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 04-23-02 12:51 PM - Post#7201
In response to Staff
Let's not forget to balance our tail blades also. Weigh them and/or balance the tail assembly on a pivot balancer. You'd be amazed how out of balance they can get after contact with the ground. A bit of sandpaper judiciously applied to the blades usually corrects the problem. Be careful not to alter the airfoil and the CG. Replacing is a much cheaper option for tail blades than main rotors. Many vibes can be traced to tail rotor.
ALso check for worn balls/ball links on the bellcranks and tail mechanisms, tails usually have exhaust oil blown into them that attracts dirt and makes great wet-sanding materials!
| Happy Flying!
It's not how much it costs, it's how much you can afford! |
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RaptorCop
Member
Posts: 29
Loc: Visalia, Ca USA
Reg: 12-08-01
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04-23-02 01:07 PM - Post#7205
In response to Staff
Flying wooden blades? Don't forget to shrink the plastic covering. I Let a set of woodies sit in the sun last weekend and I was amazed at how loose the covering became. I took them home and hit it with the wife's hair dryer and tightened them up nicely. I took a brand new pair and did the same thing. I was surprised at how much more the covering shrunk!
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nsacco
Senior Member
Posts: 453
Loc: Raleigh, NC, USA
Reg: 01-10-01
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 04-23-02 06:59 PM - Post#7218
In response to Staff
If you're having a problems with erratic tail control on belt-driven helis, check for pulley slippage. Loose belts or worse - the pulley slipping on the axle. Usually the tail is fine, then slowly the tail will begin to rotate unexplainably. It gets worse as the parts heat up from friction. Soon total failure will leave you with a pirouetting out of control helicopter. Look for roll pins or other pins holding pulleys on the axles missing in action or loose plastic pulleys distorted from heat.
| Happy Flying!
It's not how much it costs, it's how much you can afford! |
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Micro Rotors
New Member
Posts: 20
Loc: So. Cal USA
Reg: 04-06-02
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04-24-02 01:49 AM - Post#7223
In response to Staff
You ever have those tail blade mounting nuts come loose every now and then?
I always replace them with nylon insert locking nuts, They do not require lock tite and they stay put. You will want to replace the nut after you remove it 10 or so times.
Bill
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sbalder
New Member
Posts: 15
Loc: Westland, MI
Reg: 10-16-01
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04-24-02 04:34 PM - Post#7244
In response to Staff
I have used a High Point balancer for blades, rotor heads, tail rotors, and fans for some time. I was never satisfied with how it balanced blades so I purchased a digital gram scale. What a difference! With this device I can balance blades so that they match to a tenth of a gram!
Here's what to do- most blades currently being sold have some degree of pre-assembly and are fairly closely matched. Complete the final assembly of the blades and then check the lengthwise CG by laying the blades on the sharp edge of a table. Your CG should be within 2mm. Then weigh the blades individually on the gram scale. Add trim tape to the lighter blade until the weights are identical. If the CG is correct, add the trim tape to the lighter blade at the CG point. If not, adjust the position of tape to bring the CG in or out as necessary. Your goal is to get blades that are identical to each other in both weight and center of gravity. All the blades I currently fly are equally-matched in weight, but you can go as high as 2 grams off and not have a vibration issue.
The scale I purchased was the Pro Scale 500 from My Weigh. I bought it from http://www.oldwillknott.com/pr500blk.html for about $75.
If you order one, spend the extra few dollars and get a set of calibration weights.
There are several vendors selling these type of scales on Ebay. My recommendation for helicopters is to only buy a new scale with 500gram capacity, and 1/10th gram resolution. Money well spent.
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volare
Member
Posts: 66
Loc: Cincinnati
Reg: 01-04-02
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04-25-02 12:05 AM - Post#7255
In response to Staff
Don't forget to glue the blade grips on if you fly with wooden blades. Thick CA or epoxy will do the job well. What you should do is take of the grips and remove the covering from the area under it if there is any. Then apply a generous layer of glue and screw the grips back on. Rub off any excess glue that squeezes out.
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Scotty740
Senior Member
Posts: 240
Loc: Nashport, Oh USA
Reg: 01-29-01
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04-25-02 11:43 PM - Post#7307
In response to volare
I mark one blade a grip on all my helis so that the right blades go back on the right grips. I also use the marked blade for setting pitch. When adjusting pitch with my pitch gauge I use the marked blade. Then when adjusting tracking I adjust the unmarked one so I know that my pitch range doesn't change.
| Scott Stickle
IRCHA # 1660
There is a very fine line between Hobby and Mental Illness |
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volare
Member
Posts: 66
Loc: Cincinnati
Reg: 01-04-02
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04-28-02 02:57 PM - Post#7391
In response to Staff
Blade Tension
Generally your main rotor blades should be tight enough that they don't fall over when you tip the helicopter on its side. This usually prevents vibration as well as boom strikes on rough landings.
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basmntdweller
New Member
Posts: 21
Loc: Indianapolis IN USA
Reg: 12-03-01
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04-28-02 09:53 PM - Post#7401
In response to Staff
You can compare the chordwise balance of your blades by hanging them from a nail in a wall and marking where the LE or TE at the tip hangs to. The second blade should hang to the same place. If it hangs to the rear, the blade needs weight added to the TE and vice-versa.
Later,,, basmntdweller
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Anonymous
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05-20-02 05:19 PM - Post#8050
In response to Staff
Re; Carbon Fiber Blades
When its time for you to move up to Carbon Fiber Blades that come pre-balanced. Always continue to Balance each blade as you would if they were wooden blades, checking them for CG and their spanwise balance. Sometimes these pre-balanced blades from the manufacturer come slightly off balance even though they claim to be precisely matched. Its always better to double check them just to make sure. Happy Flying!!
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Mike Robins
Senior Member
Posts: 140
Loc: Woodbridge, Va. USA
Reg: 02-28-01
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06-15-02 12:09 AM - Post#8651
In response to Anonymous
A very easy way to recover your rotor blades with shrink covering is to slip the covering over the blades and then to shrink the covering over a steaming tea pot. I have used heat guns before and have burnt the covering, a hair dryer works, but is slow. Working the new blade over a steaming stream back and forth works great, and shrinks it tight.
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tisrich
Member
Posts: 55
Loc: Western NY State
Reg: 06-17-01
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06-18-02 05:23 PM - Post#8713
In response to Staff
Raptor 30 owners: rule of thumb for setting tail rotor pitch is to leave space of 4.5mm between inside edge of brass pitch slider and tail case when setting up rudder servo at neutral setting.
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Alexy
Member
Posts: 87
Loc: Warrenton VA
Reg: 10-08-01
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06-28-02 12:49 AM - Post#8894
In response to volare
Remember to re-balance the blades after you glue the holders on too!
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Buzzin Brian
Senior Member
Posts: 793
Loc: Okc, Ok, USA
Reg: 01-29-01
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07-01-02 11:19 PM - Post#8944
In response to Alexy
Never assume that blades are OK after a crash where they are not destroyed. There can be internall damage that cannot be seen by the naked eye. When in doubt, throw them out. It is better to buy a new set of blades, than have a rotor head explode due to internal cracks and breaks. This can at the least cost you a crash or your model. And at the worst cause seriouse injury. Safe practice is the best practice you can get. So fly, enjoy, and be safe at all times.
| Brian
Build it, Fly it, Crash it. Repeat as often as needed. |
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Buzzin Brian
Senior Member
Posts: 793
Loc: Okc, Ok, USA
Reg: 01-29-01
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07-01-02 11:28 PM - Post#8945
In response to Buzzin Brian
For belt driven tails!
Always check the belt on your tail when there are extreme temperature changes. It might have been tight yesterday when it was 75 degrees. But tommorow when the temp drops to 40, you will generally find that it is not so tight any more. And that type of weather changes do happen. I live in Oklahoma, I should know.:~) Make that one of your preflight checks. And continue to check it as the day goes on. It might not change as soon as you get to the feild. Given that the model was most likely kept in the house, and transported in you nice and warm vehicle. Just keep an eye on it, and adjust as needed. Don't forget about that tailrotor pushrod either. Unless you have a boom mounted servo. Any adjustments made to the tail boom length (belt tension) will effect the tail rotor trim.
Enjoy!
| Brian
Build it, Fly it, Crash it. Repeat as often as needed. |
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jmkirsch
New Member
Posts: 4
Loc: Rochester, NY
Reg: 07-01-02
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07-03-02 11:01 PM - Post#8973
In response to Staff
On the Raptor 30 (and possibly many other helis), the outermost radial bearing in the blade grip is held in my two M3x5 self-tapping screws. I noticed in my Raptor 30 that there was a gap between the edge of the outer radial bearing and the edge of the grip; this creates some slop in the head. By simply filing the plastic that the screw buts up against a little at a time, this slop can be completely eliminated. I eliminated wah-wah's in descents with this mod.
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jmkirsch
New Member
Posts: 4
Loc: Rochester, NY
Reg: 07-01-02
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07-03-02 11:04 PM - Post#8974
In response to Staff
In the Raptor 30, an M3x14 socket screw holds the mixing lever into the flybar seesaw hub. A collar is placed over this screw for the bearings to run on, but there is a small amount of play between the screw and the collar. This creates a bit of slop, and can easily be eliminated by wrapping some teflon plumbing tape around the socket screw.
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Tom Berg
Senior Member
Posts: 307
Loc: Clovis, California
Reg: 03-13-00
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07-05-02 04:40 PM - Post#8996
In response to jmkirsch
Some companies make a long shoulder bolt for the blade grips. They have a lot less play than the threaded bolts and do not bend as easy at high rpm. KSJ makes 3mm and 4mm long shank bolts and JR has the 4mm and 5mm (I think) long shank bolts. They are much nicer than standard threaded bolts.
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jack01
New Member
Posts: 13
Reg: 08-22-02
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08-22-02 02:01 AM - Post#9755
In response to Tom Berg
You need to make sure that your tail pitch slider cant move too far on your Raptor 30 because if it does, it can stick to one side, and that can make your flight VERY intresting and short.
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Alan Gilmore
New Member
Posts: 11
Loc: Baltimore, Maryland
Reg: 01-23-03
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01-30-03 04:25 PM - Post#15330
In response to Staff
Balancing main rotors can be much easier if you have a head button that you can apply a balancing target on. The attached file can be printed on a color printer and applied with double sided carpet tape. It must be precisely centered, and the red/green squares should be next to the main rotors, while the yellow/white squares should be next to the fly bars.
Do a static balance of the blades on your bench first.
Then spin up your main rotors slowly with the engine and watch the target carefully. When properly balanced the black dot will remain in the center. If imbalanced the black dot will form a circle or oval.
Notice the color in the center of the circle. Stop the rotor and look at the blade that is next to that color. That is the blade that you need to add weight to.
You will notice that the balancing target will indicate if there is any imbalance in the fly bars also!
I have used these for about a year now, and finally feel comfortable with the design. Yes, it took lots of work to come up with something so simple!!
The above instructions are the simple version, and I suggest that you experiment with it to see how it works.
Several other points I should make:
-Apply carpet tape to the back and clear packing tape to the top before you cut it out. The packing tape makes it water and fuel proof.
-The circles on the target are for helping you cut it out, pick the size that fits your head button.
-Be sure to spin up the rotor slowly. Often at higher speeds the circle changes to a dot and the imbalance is not visibly noticeable.
-If you see multiple circles/ovals, do not get discouraged. You are experiencing multiple oscillations in your rotor head. There are many reasons that this can happen, so look at all the possible causes...loose parts, sloppy linkages, tracking problems, etc.
-Mount it very carefully in the center!!! My latest method is to mark the center of the headbutton (if it doesn't already have a dimple). Then cut half way through to the center of the target with sissors. This allows you to fold back part of the target while aligning the center of the target with the head button.
Let me know how you like it!!!!
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Alan Gilmore
New Member
Posts: 11
Loc: Baltimore, Maryland
Reg: 01-23-03
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01-30-03 04:54 PM - Post#15332
In response to Alan Gilmore
Okay, I am not able to upload the .jpg, what am I doing wrong?
The .jpg is on my hard drive, and I used the "browse" button with Netscape 7 to find it, but it still did not upload to the server!@#$%^&*?????
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Scott Owens
Member
Posts: 34
Loc: Dallas
Reg: 05-27-03
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06-06-03 09:50 PM - Post#20854
In response to Staff
I use the Koll Rotor Pro Balancer and a GOOD gram scale to balance ALL my blades. So far the claims of perfectly matched blades right out of the box has not been true for me! The weight may be the same but the CG is always WAY off!
The instructions are confusing at best and I don't do it their way.
If your blades came finished than the weights should already be installed and visible through the cover. IF they have weights! Some don't!
Check the weight of each blade. One may be heavier. If it is note the difference in the weights and mount it on the rotor pro. This will be your master blade. Balance it on the rotor pro. Mark the CG through the hole in the bottom of the rotor pro. Now remove the master and mount the slave blade on the rotor pro. You will now just place a piece of tape (equal to the difference in the blade weights) on the slave blade in a spot that centers the bubble level. At this time just set the tape temporarily on the blade.
Now both blades should be the same weight and balance span wise.
Mark a spot on the span wise CG on both blades. Now turn the rotor pro sideways and slide in the master blade centering it on the spot you just made. Level to get the chord wise CG. Mark the chord wise CG from below. Slide your span wise CG mark to match the chord wise position thereby combining the two marks into one. This will be your master blade CG point. Remove the master and check the slave. If you're lucky they will match. Most likely they wont! Try and position the your piece of tape toward the lite side of the blade to get the chord wise CG to match. If it does you're done. If it doesn't you will have to add more tape to the lite side until it does. Of coarse this extra piece of tape will make the slave blade heavier than the master and you will have to add a equal weight of tape to the CG of the master blade to get them back in balance. This is easy to do, just center it on your span wise/chord wise CG mark on the master blade. This will increase the weight but not change the CG so both blades should still match. Check one against the other to be sure.
Now although I told you the points are the blades CG the truth is there not. Why? Because the rotor pro is also being balanced with the blade. But it doesn't matter because what you're doing is getting the blades to match in weight/span wise CG/chord wise CG and they are. Its just that the actual CG although they are the same they will not be on your marks. Don't let this confuse you. Both blades are now exactly the same!
You can use any kind of tape. Tracking tape, clear tape just as long as it wont come off. Sometimes I just use Scotch Brand tape and so far its not come off.
If your blades are much different in weight you may not be able to do this with tape. That's when it gets tough! Drilling holes to glue in brass dust and all that! I don't mess with all that. I don't find the new built blades to be that out of balance as far as the weights are concernered. But if you build your own it can happen. And for that reason I don't bother building blades anymore. It doesn't hurt to take your rotor pro and gram scale to the hobby shop and check the blades before you buy if you can! You might get lucky and find that so called perfect set!
I think most people just check the weight difference, bolt them on and fly. But if you've already got the rotor pro you might as well do it right. At least you wont be wondering if that vibration is coming from your blades.
Scott
The Sun's up. Go Fly! 
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WildMisterT
Member
Posts: 97
Loc: Canada
Reg: 06-17-03
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 07-21-03 04:32 PM - Post#23314
In response to Staff
To balance my Main Rotor Head+Flybar+Paddles, I remove the Head and Shaft from the Heli and put it into a PowerDrill, secure the shaft as a drill bit, then select the proper direction, hold the drill vertical over my head and spin the rotor.
That way I was able to troubbleshoot a vibration problem I had. Now be shure to tight the shaft properly, you don't want the rotor to fly off the drill...be carefull.You will see and feel the vibration if any, then ajust paddles, flybar, etc...
| Don't Drink and Fly... ;) |
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velocyraptor
Member
Posts: 47
Loc: Jakarta, Indonesia
Reg: 08-28-03
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10-17-03 01:30 PM - Post#28296
In response to WildMisterT
For anyone who looking for cheap tail boom replacement, go to aluminium store (they made alu display, etc). I get tailboom replacement for my Raptor with only $4 for 10 unit tailboom. So it only 40 cent each. It's slightly heavier but worked perfectly. The raptor diameter is 7/8 inch.
Albertus Herinanto
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Duffy
New Member
Posts: 3
Loc: Virginia
Reg: 03-03-04
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12-29-04 11:13 PM - Post#55824
In response to Alan Gilmore
I like the idea about the color wheel. I can't seem to download the att.??
Happy flying.. 
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casio
Professional User
Posts: 68
Loc: -n-load
Reg: 04-03-07
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04-27-07 06:41 AM - Post#83739
In response to volare
I am getting ready to run new wood blades, I did what you suggested. I am curious why they even have a coating on the blade. Is it ok if the plastic is not sealed near the grips? the leading edge of the blade's plastic is loose.
| DUCK!!! HEAR IT COMES!!!!!!!! |
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