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HomeAircraftHelicopterBlades and Night Flying › Tail blades
01-15-2011 04:32 PM  7 years agoPost 1
seldred

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Newnan, GA

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Just recently got back into the hobby and starting to fine tune more helicopters. I've always run 95mm tail blades on my 50 size helis. How would running 92mm blades effect flight? Advantages/ Disadvantages?

Thanks
-Steve

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01-15-2011 05:02 PM  7 years agoPost 2
billiano

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Greece ,Patras

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Its simple physics.
But why to mess with smthng that already works?

Esprit Model Flight Team
Kasama Srimok 90N FBL
TDR Rigid 90

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01-15-2011 05:04 PM  7 years agoPost 3
seldred

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Newnan, GA

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Care to explain?

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01-15-2011 05:28 PM  7 years agoPost 4
JOLT

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Baltimore, MD

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Taking a shot here....assuming the shorter blades have less surface area, you would get less tail authority with the smaller/shorter blades.

More responsive tail from the longer blades--assuming more surface for deflection.

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01-15-2011 05:34 PM  7 years agoPost 5
billiano

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Greece ,Patras

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Sorry for the delay I was looking smthng else.
I agree with the previous opinion.
But smaller blades don't push that much the engine in clockwise pyros

Esprit Model Flight Team
Kasama Srimok 90N FBL
TDR Rigid 90

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01-15-2011 05:38 PM  7 years agoPost 6
AirWolfRC

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42½ N, 83½ W

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It's not just the length, it's also the blade chord.

More blade area = more authority

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01-15-2011 05:41 PM  7 years agoPost 7
billiano

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Greece ,Patras

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+1

Esprit Model Flight Team
Kasama Srimok 90N FBL
TDR Rigid 90

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01-15-2011 05:41 PM  7 years agoPost 8
junkpilot

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Alamogordo N.M.

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Tailblades
Seldred;
This whole forum works like "Who wants to be a millionair". Every person in the audiance has a pad with buttons on it. If you"The contestant" ask the audience for help everyone is going to answer even if they have no freaking idea what the subject is. In the end you and only you have to sort out the Fools,Liars and Ignorants.
95mm-105mm is what you expect to find on a 60 or even a 90 size. Go ahead and use 92mm you will have no problems.
Junkpilot

When you fly JUNK it's hard to tell when you've crashed!

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01-15-2011 05:47 PM  7 years agoPost 9
GC1

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Manchester, UK

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My friend and I both run 85mm blades on our Trex 600s. The reason for this is that the 95mm blades have a habit of catching on our uneven field and it strips the gears.

I have found it to be generally fine for my flying including 3D, although this thread has prompted me to try the 95mm blades again to see if it affect some of the more aggressive 3D moves or high speed backwards move where the tail can blow out.

In answer to your question they will work fine for most things.

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01-15-2011 05:55 PM  7 years agoPost 10
Solmanbandit

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Tucson , AZ

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There was an article recently in RC Heli talking about tail blades. Basically longer tail blades will give more authority, but rob some power from the motor. They also said to run the shortest blades possible to gain more power, but find a size that works for your flying style.

Trex 700E / Trex 500 ESP - Ikon/ HD 500 - Ikon 2/ Goblin 500 Ikon 2

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01-15-2011 07:56 PM  7 years agoPost 11
seldred

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Newnan, GA

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Awesome! I think I have a good understanding of how they effect performance! I appreciate all the replys

-Steve

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01-16-2011 01:56 AM  7 years agoPost 12
RAK402

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Alhambra, CA

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I am going to disagree with RC Heli (my favorite model magazine) on this one...

Longer tail blades (within reason) work better (IMHO) than shorter ones.Longer tail blades, more disc area, more tail authority. Torsionaly stiffer tail blades work better. If your tail is robbing enough power that you notice it, you have other problems (power system problems).

I (along with others) test tail rotor blades for KBDD, and so have had a lot of different tail rotor blades on many machines (different plastics, different airfoils, different shape, length, chord, etc.). I also have on had a number of different machines from different manufacturers to work with.

You can easily feel the difference with the different types, materials, and sizes of blades.

Right now, these are the types and lengths of tail blades I am running on my .50/600 sized machines:

Trex 600E, Knight 50 Pro, Knight 3D: 92mm TWEE Tail Blades

Raptor 50 (not the stretched version): KBDD 85mm

Compass 6HV: New KBDD prototype 96mm tail blades (best so far).

Kyosho Caliber 700 (550 sized machine): KBDD 85mm.

All flying done from grass fields-no clearance problems on the machines listed above. All the machines above had the tail blades upgraded from CF (and yes, it was an upgrade from CF) or OEM factory plastic tail blades.

I do a lot of backwards inverted and like backwards, outside loops for some reason. If there is a tail blade issue it will usually show up in a backwards, outside loop.

Team KBDD/Compass Team Manger/Experience RC/Team JR Americas/WR Field Rep

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01-16-2011 02:07 AM  7 years agoPost 13
JOLT

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Baltimore, MD

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"This whole forum works like "Who wants to be a millionair". Every person in the audiance has a pad with buttons on it. If you"The contestant" ask the audience for help everyone is going to answer even if they have no freaking idea what the subject is. In the end you and only you have to sort out the Fools,Liars and Ignorants."

Man, that is a nasty approach when I am trying to help here. I don't think I am a fool, liar, or ignorant. I don't understand why you are blanketing fellow members with a statement like that. Just giving a competant reply to a straight forward question......

I haven't received my pad with buttons yet, but it must be on the way.

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01-16-2011 02:11 AM  7 years agoPost 14
RAK402

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Alhambra, CA

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Jolt,

I agree with your comment above.

Also, you were (of course) correct:

"Taking a shot here....assuming the shorter blades have less surface area, you would get less tail authority with the smaller/shorter blades.

More responsive tail from the longer blades--assuming more surface for deflection."

Team KBDD/Compass Team Manger/Experience RC/Team JR Americas/WR Field Rep

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01-16-2011 02:32 AM  7 years agoPost 15
seldred

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Newnan, GA

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JOLT- I have read and seen many of your posts before here on RR. I wouldn't place you (or anyone else that has commented on this topic so far) under the category of fools liars or ignorants. Although, I have read some threads where I would definitely place many under that category! IMO you seem to know your stuff quite well!

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01-16-2011 02:09 PM  7 years agoPost 16
Jeff polisena

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westpalmbeachflorida usa

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On CY tails the 95 mm have thin chord and length on the 92mm chord is thicker but length is shorter . I think you just need to try different ones to get the feel you like .

I stole it ,flew it and gave it back ;)

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01-16-2011 02:45 PM  7 years agoPost 17
Richardmid1

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Leeds, England

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Some 50's have different tail gear ratios, if your 50 has a high speed tail then the 92's would probably be better, if it is slower then use 95's.

Also if person A is using 1800rpm head speed with 95mm tail blades and person B is using 2100rpm head speed with 92mm tail blades, both should have similar tail authority.

60% of the time, it works every time!

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01-16-2011 03:03 PM  7 years agoPost 18
Jeff polisena

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westpalmbeachflorida usa

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Just too many varibles to consider .

I stole it ,flew it and gave it back ;)

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01-16-2011 03:48 PM  7 years agoPost 19
sonnyhad

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Holland,Mi

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A quick note here for 600's hitting the grass. Use the tail fin from the 700, it is an inch longer than the 600 part. Helped me a lot! Then I just use the size tail feathers the manufacturer recommends!

Bald Pilots usually wear hats!

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01-16-2011 06:29 PM  7 years agoPost 20
AirWolfRC

rrProfessor

42½ N, 83½ W

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A formula can be made using
D=shaft to blade bolt length
L=blade length
C=blade chord
to determine if one blade is better than another

. . . assumming the same airfoil . . . which is a good assumption here.

A rough but simple formula is ((D + L)x 0.75)² x C = number

Even simpler for comparing is L² x C = number

The higher the "number" the better.

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