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HomeScaleAircraftScale HeliScale Helicopter Main Discussion › Question on Scale blades versus standard blades
03-12-2010 08:41 AM  8 years agoPost 1
Yug

rrMaster

UK. Herts

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Can anyone give me a very rough idea of the amount of thrust (and drag) offered by a scale blade as compared to a normal blade for a given HS ?

Vegetable rights and Peace

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03-12-2010 12:48 PM  8 years agoPost 2
Copter Doctor

rrProfessor

Enterprise/ft.rucker ,al- home of army aviation

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others may have different oppinions on this but for me, a scale blade isnt so much performance, but appearance. what is an idealscale blade? well, something that looks the part while at the same time makes the heli fly well. the blades on fullsize helis look a zillion different ways. i dont believe a blade manufacturer is willing to make sets of each and every one,not even for thepopular helis.
flat bottom or semi symetrical blades are popular among sclae birds because they provide more lift for cusioning autos. i dont personally think they make a diference for normal flight what the airfoil shape is, only when it comes to autos.
as far as appearance,l i think any set of blades can be made to look scale simply by painting them appropriately.
i simply choose blades which have the performance i ike, then paint them to match the fulsizei am modelling and go fly

drive a rotary, fly a rotorcraft

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03-12-2010 01:10 PM  8 years agoPost 3
darrens

rrKey Veteran

United Kingdom

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Semis do produce more lift for the same power drain and the profile is also more aerodynamic, so less drag. Overall they are more efficient and while you wont notice that on a nitro bird, you will notice better run times on electric birds where duration is more criticle.

He who dies with the most toys is the winner!

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03-12-2010 01:31 PM  8 years agoPost 4
Richard Morgan

rrApprentice

Virginia Beach, Virginia USA

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Yug:

If you are looking for stuff for your Wessex. I am going to run the Vario pt #440 semi blades (two sets) on the four bladed head from RCaerodyne that does not require a driver for the timing of the head on my Wessex. I highly recommend this set up, it is very nice. Also I am changing out the motor on the Trex mechanics to a 650kv motor 10 tooth pinion and will run it at 12s. Should be around 1500rpm at tne head. I have flown this set up before.

Richard

Is it just me, I thought all Helicopters flew in 3D......Hmmmm?

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03-12-2010 03:18 PM  8 years agoPost 5
Yug

rrMaster

UK. Herts

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What main gear would that be ? Your figures suggest 160T gear

Vegetable rights and Peace

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03-12-2010 04:57 PM  8 years agoPost 6
Richard Morgan

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Virginia Beach, Virginia USA

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Still running the 170tooth in gov. mode on the ESC @ 85 to 90% factoring in efficiency of most motors and 5% mechanical loss. This also depends on the Lipo. I always figure them slightly derated.

This set up is currently on a buddy of mine's Augusta A109 using the Trex 600; very nice!! I also will try it with an 11 tooth pinion as well to achieve what I am looking for . Sometimes you have to work the system and because these are variables unique to each system the results are just that; "variable" but usually close. There is a headspeed calulator that is known as Fredrik "MrMel" Melin's Heli Headspeed Calculator - 5.0 that I use and it appears to be better than most.

Here is the link http://heli.dacsa.net/CalculatorV2/

Richard

Is it just me, I thought all Helicopters flew in 3D......Hmmmm?

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03-12-2010 05:07 PM  8 years agoPost 7
Yug

rrMaster

UK. Herts

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Factoring in efficiency, wouldn't that therefore give you no more than 1200 at the head or have I missed something ?
37 * 85% * 650 * 10/170 = 1202

Vegetable rights and Peace

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03-12-2010 05:11 PM  8 years agoPost 8
Richard Morgan

rrApprentice

Virginia Beach, Virginia USA

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Look back at my previous post. I edited in a headspeed calculator I like to use.

Richard

Is it just me, I thought all Helicopters flew in 3D......Hmmmm?

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03-12-2010 05:14 PM  8 years agoPost 9
Richard Morgan

rrApprentice

Virginia Beach, Virginia USA

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Yug:

You are right, I goofed I meant to put 12S not 10s... Big difference!!!

12S will give the headspeed I was talking about, pardon me while I get me a drink!

Richard

Is it just me, I thought all Helicopters flew in 3D......Hmmmm?

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03-12-2010 05:32 PM  8 years agoPost 10
Yug

rrMaster

UK. Herts

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Aha, that makes more sence. I've been unsuccessfully trying to massage the figures to get your 1500.
800kv @10s 10/170 also comes close to 1500.

Vegetable rights and Peace

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03-15-2010 01:26 AM  8 years agoPost 11
Yug

rrMaster

UK. Herts

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Richard, where is the balance point on the Vario 440s ? I ask because I'm using a rigid head. After looking at the specs of the 440s, I see they are wide chord. Can you reccommend any more scale like narrow chord semi blades ?

Vegetable rights and Peace

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03-15-2010 04:36 PM  8 years agoPost 12
Richard Morgan

rrApprentice

Virginia Beach, Virginia USA

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Hi Yug

They appear to balance right down the blade bolt hole or slightly forward. I haven't put them on the balancer to check. As to narrow cord scale blades, this an area where we are lacking maufacturers support. I believe OF has a set of narrow cord, but they are far to long. I don't recall anything from Vario. Joe Howard at EastCoast Scale Heli Vario I am sure could shed more light on that. The head I am using for my HC2 is the one that RC Aerodyne sells that does not require a driver. I have had the opportunity to try this head and it is not bad at all evn without stabilization, and Vario blades bolt right up without spacers

Richard

Richard

Is it just me, I thought all Helicopters flew in 3D......Hmmmm?

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03-15-2010 05:54 PM  8 years agoPost 13
Yug

rrMaster

UK. Herts

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Crikey, I am supprised how far and few between 600mm semis are

Hmmmm, just came across these....know anything about them ?
Also remember coming across some Rototechs somewhere.

SWE Semi-symmetrical CF 600mm

Vegetable rights and Peace

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03-15-2010 06:20 PM  8 years agoPost 14
doorman

rrProfessor

Sherwood, Arkansas

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Semi's
You were correct about the Roto Techs.....

http://www.centuryheli.com/products...C¤tid=461

There certainly are not a bunch to choose from!!!! Maybe now with all the slip on fuselages coming out someone might realize there could be a market for some choice!!!!

Stan

AMA 2918-Team Spin Blades,,Castle Creations, Unique Aircraft

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