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HomeAircraftHelicopterBlades and Night Flying › Blade weight question
04-05-2009 06:18 PM  9 years agoPost 1
cdrking

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Seattle

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I have two sets of 325 mm blades for my Beam 450. One set is the stock blades that came with the kit and the other set are 325 mm Radix.

I weighed the blades and here's what I have.

Stock blades:

Blade #1: 27.64 grams
Blade #2: 27.36 grams

Difference: .28 grams

Radix blades:

Blade #1: 21.92 grams
Blade #2: 21.89 grams

Difference: .03 grams

Is that enough to make a difference in how they (stock blades) fly? I weighed some paper and made up .28 grams and just sitting there it looks like quite a bit of weight.

How much can they be off?

Thanks,

Jeff

To hover is divine, the alternative is rather PLANE.

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04-05-2009 06:48 PM  9 years agoPost 2
Funky Trex

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Westerville, OH - USA

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I wouldn't worry about that little difference. I have mixed and matched blades from different sets that are farther off than that with no noticable problems. Sometimes I use some tape to get the weights closer but most times I don't bother unless it is over 1/2 gram difference.

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04-06-2009 01:51 AM  9 years agoPost 3
oldfart

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Vancouver, Canada

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What is more relevant is the % of difference.

e.g. a 0.5 gram difference on a 140 gream blade is very insignificant (only 3/10 of 1%). That same 0.5 gram difference on 28 gram blades is much more significant (a full 1.8%!). Almost like having a 2.5 gram difference on the aforementioned 140 gram 600 blades. That 2.5 gram difference would certainly result in a very noticeable vibration on the 50 sized heli using the 2.5mm misballanced 600mm blades.

Note that the .03gm difference on the Radix is only a 1/10 of 1 % difference so it would not be of significance. But I think the 0.28gm difference on the 27 gram blades is relatively significant, as it represents a full 1% difference..so it may well cause some noticeable vibes.

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04-06-2009 02:49 AM  9 years agoPost 4
cdrking

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Seattle

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so it may well cause some noticeable vibes.
I held off on noting that I do have a vib. This is on a Beam 450 and all shafts and bearings have been changed. The only thing that's not been changed are the blades. I will try them (Radix 325's) tomorrow and see if that makes a difference.

Thanks,

Jeff

To hover is divine, the alternative is rather PLANE.

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04-06-2009 03:08 AM  9 years agoPost 5
Funky Trex

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Westerville, OH - USA

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I thought the little helis were supposed to vibrate like that

If the radix blades fix the vibe, you should try balancing the other set to see if the weight difference was the problem.

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04-06-2009 04:27 AM  9 years agoPost 6
cdrking

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Seattle

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Actually if I fly it fast enough I don't even see the vibration, maybe that's the key.

Jeff

To hover is divine, the alternative is rather PLANE.

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04-08-2009 04:08 PM  9 years agoPost 7
cdrking

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Seattle

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I had a chance to fly and test yesterday. I flew a flight with the stock blades with the "weight issue" and then flew a flight with the Radix blades. HUGE difference, when I first put the Radix blades on they were out of track by about a quarter inch. The stock blades with the same linkage settings were perfectly in track. Also with the Radix blades the machine was vibration free. I couldn't believe the difference, the vertical fin on the tail was now standing still, no vibs.

One of the guys at the field was looking at the stock blades after I took them off and the trailing edges were warped. I think all around they were just a crap set of blades.

Enjoying the heck out this heli now.

Jeff

To hover is divine, the alternative is rather PLANE.

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04-08-2009 06:06 PM  9 years agoPost 8
red_z06

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Dumont, NJ

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Jeff,

Add some packing tape near the CG of the lighter blade. 0.3g on a 325 is hugh. I normally apply a decal of some sort on a lighter blade to take out 0.1g difference.

www.JustinJee.com

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04-08-2009 08:38 PM  9 years agoPost 9
cdrking

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Seattle

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.03 gram difference with the Radix

.28 gram difference with the stock blades

To hover is divine, the alternative is rather PLANE.

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04-08-2009 08:43 PM  9 years agoPost 10
red_z06

rrProfessor

Dumont, NJ

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I rounded your 0.28g to 0.3g. Few layers of packing tape should get it in line.

www.JustinJee.com

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04-08-2009 09:03 PM  9 years agoPost 11
cdrking

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Seattle

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Yeah I thought about that but I like the Radix blades now. The stock blades are also warped a bit on the trailing edges.

Jeff

To hover is divine, the alternative is rather PLANE.

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04-08-2009 09:19 PM  9 years agoPost 12
red_z06

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Dumont, NJ

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Do you recall the blade that was on our Beam when you flew it? How about that one?

www.JustinJee.com

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04-09-2009 02:42 AM  9 years agoPost 13
cdrking

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Seattle

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No I don't remember Benny, I was just concentrating on not crashing Justin's helicopter.

Did it have some tape?

Jeff

To hover is divine, the alternative is rather PLANE.

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04-09-2009 03:08 AM  9 years agoPost 14
red_z06

rrProfessor

Dumont, NJ

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No. It was a Thunder Power blades. If you haven't tried it, you might want to do give it a try.

www.JustinJee.com

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04-15-2009 05:32 AM  9 years agoPost 15
Sam2b

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Tacoma, WA

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Jeff, when you added the packing tape weight, where on the blade did you put it? I would figure you'd put it at the CG of the respective blade (about center)?

Then you have the aerodynamic issue. Yes, true they are small blades, but I respect the small heli's like the big ones.

I've never balanced any of my Radix 325mm sets. In fact in the past I actually put two un-broken blades together as a set after a crash, and no vibes to the naked eye. Thrash'em and crash'em; maybe that's what is not happening enough with your Beam?

PS: I always make it a point to replace the tail shaft after a crash, and I don't have vibe issues afterwards.

_Sam B_

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04-15-2009 05:42 AM  9 years agoPost 16
cdrking

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Seattle

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I haven't tried to fix the stock blades with the packing tape method. I went out today again and flew the Radix blades and they were working perfect. What's interesting is when I got to looking at the Radix blades they have some tape on them right at the leading edge and it looks like it's right on the CG of the blade. They fly great though.

I did however test the skid limit on the Beam. I did a tail slide and almost stuck it in hard. I caught the heals of the skids on the grass and had to use some OH S@#! power to get out. Grass was hanging off the skids for the rest of the flight.

I'm not going to spend too much time tweaking the Beam, I have bigger fish to fry.

Jeff

To hover is divine, the alternative is rather PLANE.

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04-15-2009 06:26 AM  9 years agoPost 17
Sam2b

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Tacoma, WA

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had to use some OH S@#! power to get out. Grass was hanging off the skids for the rest of the flight.
LMAO! NEU 1107 to the rescue.

_Sam B_

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