RR Rated M For Mature
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 347 ONLINE 17 EVENTS SEARCH REGISTER  START HERE
 
1 page409 viewsPOST REPLY
CarbonXtreme . Midland Helicopters . HeliProz

.
.
Scale Model RC Helicopters > Four bladed rotor head
 
 
jackheli
Elite Veteran
Location: Vancouver - Canada

My Posts This: Topic  Forum
What do I need to convert a two blade head into a four-blade head other than obviously the blades and the new head? Do I need a helicommand or is my Futaba 10C capable of applying the mixing? Is the swashplate the same? I suppose there are no washouts, correct?

Thanks. This is an undiscovered country for me, so that's why the basic questions.



Anyone who has never made a mistake has never tried anything new
Albert Einstein
07-02-2009 08:42 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

My Posts This: Topic  Forum
simplest way, IMO, is to put one of the various head gyro units on (Vbar, Helicommand, Skookum, etc.). Get it to fly well with original head, flybarless. Take original head off, put quad head on. Make sure matched pairs of blades are opposite each other. Make sure you're happy with expected head speed, and Hey presto you're flying four blades. I saw no real difference in flight performance from 2 to 3 or 4 blades going this route. It's pretty much plug and play with head gyros. Make sure you check phasing though, whichever route you go. You've probably never thought about it with a 2 bladed, flybarred heli.

We don't need no stinking flybars!
07-02-2009 09:19 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
Copter Doctor
Elite Veteran
Location: daleville/ft.rucker, al

My Posts This: Topic  Forum
good point but keep in mind, you dont absolutely need any of the stabilizing systems to fly a 4 bladed head. they just make thingsd a little more relaxing on the sticks. the right blades will find no need for a stab system at all
best advice is to get with someone experienced as they will save you a lot of headache setting things up. there is much to know about the muiltibladed heads and systems. i would say set things up without the stab systems first, then add whatever you want as you get things flying right.

drive a rotary, fly a rotorcraft
07-02-2009 10:09 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
jackheli
Elite Veteran
Location: Vancouver - Canada

My Posts This: Topic  Forum
Quote 
they just make things a little more relaxing on the sticks.

What changes in the flight characteristics?

Quote 
the right blades will find no need for a stab system at all;

How do we find out which are the right ones?

Thanks a bunch, guys.



Anyone who has never made a mistake has never tried anything new
Albert Einstein
07-02-2009 10:39 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
oldfart
Elite Veteran
Location: Vancouver, Canada

My Posts This: Topic  Forum
Jack

The phasing on a non flybar head is more critical then on one with a flybar that can control the consequences of any anomolies of many blades (e.g. a 3D blade is designed purposely to be dynamically unstable). So when flying any flybarless configuration, the more dynamically stable (neutral) a blade is, the better it will fly without the need for stabilization from a flybar.

Some of the specially designed blades, configured for FAI/F3C type of flying, will also be prime candidates for any flybarless configuration.
07-03-2009 12:46 AM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE  
 
 
Copter Doctor
Elite Veteran
Location: daleville/ft.rucker, al

My Posts This: Topic  Forum
differences in flight characteristics is always a tough one to answer. you wont realize how much the flybar does for you til you fly without one. the dampening effect of a flybar is no longer there and you do all the corrections and compensations yourself. i always recomend the flybarless heads only to those who are absulutely confident with their flying. not to scare the less than confident pilot away mind you, in a hover on a calm day you cant really tella difference between the two if the flybarless is set up correctly.
the way i found ideal blades two ways, experimenting with sets i already have and buying new sets. ideally, you wnat blades that are heavy so get the specs beofre you buy. i love the rotortech blades from century, they are fairly heavy so they provide stability in the hover and fwd flight. their razor thin airfoil as with most carbon blades provide less drag and thats a good thing when you got a bunch 'o' blades up there and the engine will love you for that, and they are fairly economically priced. i am flying a set on my 58D and they are pretty cool. i still look vor others that will work as well. century has fiberglass sets made for the multibladed heads i havent had a chance to try yet but will.

drive a rotary, fly a rotorcraft
07-03-2009 02:40 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   HOMEPAGE   GALLERY
 
 
jackheli
Elite Veteran
Location: Vancouver - Canada

My Posts This: Topic  Forum
Thanks guys.

I am contemplating fitting my Predator into a scale fuselage and looking at my options.

So ideally, I would strip the flybar etc. from the Pred and try a two bladed flybarless configuration first.

Do I need to extend the grip arms? I hope that buying a brand new two blade flybarless head won't be necessary since it is just for a temporary test... Any thoughts about this?

After the two bladed system is working I would upgrade the head to multi-blade... and then fit the whole thing in the fuse.

Does that sound like a plan?

I am tending towards the Skookum since I have a gyro and reports about the system are all positive.

Thanks.



Anyone who has never made a mistake has never tried anything new
Albert Einstein
07-03-2009 05:20 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

My Posts This: Topic  Forum
There's no need to buy a specialty flybarless head. You can easily modify any of the stock heads and turn the stock washout base into a swash follower (although, you'll probably want to buy a decent swash follower for the final multi blade configuration). If you go this route, I (we) can give specific guidance on the mechanical mods to the stock head. You can also do searches for your answers of course. I've modified 4 stock heads for FBL duty so far. I have also bought parts for two of them since they were going to live permanently as two bladers (or so I thought!). There are really only two critical parameters in doing a mod; phasing and servo resolution.

We don't need no stinking flybars!
07-03-2009 07:28 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
jackheli
Elite Veteran
Location: Vancouver - Canada

My Posts This: Topic  Forum
found this post:
http://www.runryder.com/helicopter/t523113p1

Was is the purpose of the follower? it doesn't connect anything to anything else...



Anyone who has never made a mistake has never tried anything new
Albert Einstein
07-03-2009 07:36 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
FrittsLogic
Senior Heliman
Location: Honolulu, Hawaii

My Posts This: Topic  Forum
The follower locks the rotation of the swash to the rotation of the mast. If you didn't have it, your swash to blade grip rods would twist and your heli would last for only a few microseconds upon spoolup. On a normal two bladed, flybarred heli, the washout base serves a dual purpose of locking the rods to the head in rotation. The swash follower you linked to looks great for a two blader, but may not work for a 4 blader. You will need 4 balls on the swash for your 4 blades, plus a 5th for the swash follower. If your swash is not pre-drilled for this, you'll have to get a new swash. This is why I say, just modify your washout base for swash follower duty, test with two blades sans flybar. Get the electronics dialed in, then put your 4 bladed head, swash, and swash follower on. Then re-check phasing and go fly. If you want to modify your stock head, and can't get Predator specific guidance, I'll give you some general pointers. It's really a lot easier than most folks think.

We don't need no stinking flybars!
07-03-2009 09:32 PM
PROFILE   PM   EMAIL   POSTS   BUDDY   IGNORE   GALLERY
 
 
1 page409 viewsPOST REPLY
Ron’s HeliProz South . MTA Hobbies . Model Rectifier Corp

.
.
Scale Model RC Helicopters > Four bladed rotor head
 Print TOPIC Advertisers 

Subscribe to This Topic

Sunday, November 8 - 9:25 am - Copyright © 2000 - 2009 runryder.com | email | link to rr | START HERE | NF