Help with MULTI BLADE rotor heads

ferretmaster · Posted: Fri Jun 10, 2011 7:24 am Post subject: Help with MULTI BLADE rotor heads

I first posted in the general topic section and no help, maybe this forum has my answer.

I am finishing up a TRex 500 clone and it will be going into a AW-109 Coast Guard fuselage. I am looking to put a four blade head on to get things looking a bit more scale. Question on selecting the head. CopterX has two different types of multi blade heads. Rigid and Floppy. I am somewhat familiar with the rigid design as I have a 4 blade HK version on a 450 clone (also with a AW-109 fuselage). Works quite well but REQUIRES a 3 axis gyro for stability. I have read that the floppy design is SOMEWHAT more stable and in the hands of the right people, may not require a 3 axis gyro. Due to skill level restrictions, I will still use one!

What in the design allows the head to be "FLOPPY"? I assume the reference is to the rotors vertical movement, but not sure. Anyone have experience with the CopterX (or other) floppy multi blade heads?

Are the CopterX ones any good? Personal or at least second hand opinions only please. If using the floppy type of head are special blades required? CopterX seem to refer to this but is not at all clear.

Many Thanks and happy (soft!) landings.

ferretmaster · Posted: Sun Jul 03, 2011 2:43 am Post subject: Answered my own question.....

With no answers I am gathering there is not much interest in multi blade heads on this forum. Crying or Very sad

But just in case. Smile

I bought the CopterX 4 blade floppy version for the Trex 500.

Looks to be pretty good quality and the metal is a good grade aluminum.

The "floppy" is accomplished by having the feathering shaft NOT be a continuous piece all the way thru the head, but stops short of the main shaft. It is held in place with a single pin and retaining setscrew at the inboard end, set at right angles to the main shaft. The shaft is a smaller diameter than the hole in the hub, this allows it to "flop" in the vertical axis. Flop is controlled by the rubber dampers at the outboard end of the hub that appear similar to the standard ones on the Trex type feathering shaft assemblies. By switching the hardness (durometer) of the dampers some adjustment can be made to the degree of flop. Confused

I am going to guess that the more "flop" in the head, the more "cone" there will be to the blades and the more cone, the more stable the heli. At least that MIGHT be the theory Question

Hope this helps someone! Idea

chopper54 · Posted: Sun Jul 03, 2011 4:10 am Post subject: post subject

hi ferretmaster,
i cant help with your scale stuff as i am still learning to keep my helicopters in one piece but i do find your info interesting. i have seen multi blade heads advertised in magazines but didn't realise they came rigid or floppy. if you think logically a three or a five blade head must have seperate shafts so presumably they can be tuned to your own taste by varying the stiffness of the dampers. if the rotors flop a bit when the heli is static it would also add to the realistic look which i think is the main aim of scale heli building. good luck with the project and a video of your floppy rotors would be nice when its up and running.

ferretmaster · Posted: Sun Jul 03, 2011 5:36 am Post subject: Floppy head...

Thanks Chopper54.

I will post a vid. when I get the beast airborne as a multi rotor heli.

At the moment I have 4 builds going on (more time than money!!) and I only have the stock pod and boom 2 blade up and running for adjustments and component verification. The fuselage, a Coast Guard AW-109 will be sitting patiently for the "thrashing" to settle down and I have a confirmed good mechanics to go with. Rolling Eyes

like that will ever happen!!

I am also working on a 600 size MIL Mi-24 from SmartModel. Same thing for the multi blade head. It takes a 5 blade version and I have not decided on the manufacturer yet. Good chunk of change in that one and will need a bit of verbal soothing to take the plunge on ANY head for that one. Confused

Suggestions anyone?

Pappy K · Posted: Wed Aug 31, 2011 7:05 pm Post subject:

Hey Ferretmaster:

How has it gone with the flexi 4 blade rotor head? I am actually trying to do the same thing, same fuselage; however the main airframe is a CoptorX 450. Check out my post on CopterX Build.

Has yours reached flight status yet? I'm really wondering how the rotor head is going to work. The literature seemed to indicate that becoz it was a flexible head there was no need to pruchase a fancy gyro.

My experiement is a long way from flight status yet. Have you figured out where all the wooden bits they supplied you with the fuselage are supposed to go?

I am in the process of installing servos and electrics.

ferretmaster · Posted: Thu Sep 01, 2011 3:35 am Post subject: Not yet Pappy

I am soooo far away from flight testing! Rolling Eyes

I am in the process of getting my wife (and self!) ready for retirement in December that ALL my helis are being neglected! Sad

Most everything is packed up with a move to Arizona expected in that December time frame. I have a very small area to work in for the time being so anything bigger than my 450's must wait.

It's killing me! Crying or Very sad

How are you coming along? I am still going with a BeastX on both the 500 and 600 scale builds. You thinking of going with "just" tail gyro? My skills do not justify that level of security. Wink

chopperaddict · Posted: Mon Mar 12, 2012 6:46 pm Post subject:

Hi there

I know this is a bit of a belated reply, but you may not have yet tried to fly your 4 blade head.

I have just done a CopterX 4 blade rigid head, using some very cheap $1.50 each) plastic thin flexible muilti blades with trim tabs (dummies). These blades are almost identical to a set I have on a Trex 450 pro with a CopterX 5 blade head except they were quite expensive, and have 2 weigjhts fitted to them to get them dead right.

However, I digress. I put this head onto a testbed CopterX, WITHOUT any electronics such as 3G, BeastX etc. Took her out for her maiden flight and got her up to a gentle hover. Just fine, nicely controlled etc. I then got braver, and after playing with ATV and DR settings some more to soften it right down, I went for a figure 8 and then a full circuit.

The heli behaved just as I would have expected from a well setup heli, apart from it being very nice and soft in the control usage.

Now my 5 blade has Align 3G on it, and has never been tried without it. Howeveer I have a theory based on all this, and that is that a 4 blade head does NOT need electronics support because the blades are exactly 90 degrees apart, so you just need to set up the phasing mechanically in the usual way and then each blade automatically handles the dreaded precession that needs electronics if you use a 3 or 5 or 6 blade head.

Make any sense ?

However, I suggest you try it out without electronics first, it REALLY DOES WORK.

ferretmaster · Posted: Tue Mar 13, 2012 12:10 am Post subject:

Thanks for the belated answer ChopperA Wink

Unfortunately all my projects are on hold 'till June this year as I retired, and moved to Arizona and the house I am moving into will not be ready 'till that time frame. I am living in my motor home (37 ft so not too cramped) but defiantly not enough room to build scale helis Crying or Very sad

I am still able to toy around a bit with a pod and boom HK 500 that I did not pack up when I moved. It has the CopterX floppy four blade head and CopterX CX 3X1000 stab unit. Steady as a rock except for a bit of tail authority loss, but that will be addressed with the four blade tail rotor I made, but have not assembled to the mechanics yet. I bought twelve sets of plastic scale blades (24 total) from Hobby King at an unbelievable low price Exclamation

I think it was about $3.00 usd a set!!! Anyway....they weigh in at about 82.5 g and with 24 to choose from I was able to match sets perfectly! They fly very well for my style....slow scale flight.
I have a couple more builds starting in June and will defiantly try the CX Floppy head main rotor w/o a FBL unit and see. Shocked

With my skills....expect the worse Evil or Very Mad

tombo242 · Posted: Tue Mar 13, 2012 6:25 am Post subject:

Hi Dave,

That's something else we have in common. We lived in a camper van while leaving UK and looking for a house here in Portugal. I well remember the hardship of wild camping.

It's not easy to keep things going when you're on the move, but at least you do know that the house will be ready for you and where it is.

I wish you the best of everything in your retirement. I found that I had never been so busy after I had sold my business and retired.

Tom.

ferretmaster · Posted: Tue Mar 13, 2012 8:45 am Post subject:

Thanks Tom.

That wouldn't be a bottle of Petite Sarah your wife (I assume) is guarding is it? Very Happy

Pappy K · Posted: Tue Mar 13, 2012 12:55 pm Post subject:

Hey Dave:

Sounds like an interesting time for you. I left Montana and retired to Australia.

Let us know when you get your 'copters back - I have not made any progress on my 4blade build as I have been building my "cave" to contain all mu computer gear and ALL of my heli gear. Just getting back to normal now.

All the best with the move - and like Tom, once retired you will wonder how you found the time to go to work Smile

Cheers
Kirk

tombo242 · Posted: Tue Mar 13, 2012 5:01 pm Post subject:

Ropieone · Posted: Sun Mar 10, 2013 11:48 pm Post subject:

I too am building a scale A-109. Mine is on a 450 Copter-X Black Angel 4-blade FBL. I tried the 4 blade floppy version rotor. It seemed to work pretty well but before I could evaluate completely, I crashed. Was a receiver problem (think it was a loose antenna connection) that caused my heli to shoot into the air like a rocket, and when I tried to recover, I landed too hard and had a major boom strike. Destroyed my A-109 fuselage and snapped off one of the blade holder shafts. I've replaced the fuselage but have returned to my original rigid 4 blade rotor (strictly economic reasons). Down the road, I think I would like to get another floppy but for now I'll be content. Am running an IKON 3-axis gyro with this set-up and love the Ikon. Am still tweaking the trim adjustments but have been sidelined the past several days because of weather. As of the moment, my heli want to drift left and back when trying to hover. Have checked and re-checked swash level but just can't seem to eliminate the drift. Am experimenting with pitch angle and head speed to see if that helps. It is already quite low. I have a governed 2200 HS (85% power) and hover with a 3-4 degree pitch. That was my setting at last attempt and I still had to add a lot of down elevator trim and could not trim in enough right aileron to overcome the left drift. Tail holds quite well except during landing when I reduce power. Once the governor disengages I get a strong clockwise tail shift before gyro compensates. Gyro gain is as high as I can get it without tail oscillation.
I would love to hear from other scale enthusiasts. I am by no means an expert... very far from it. Without anyone in a reasonably close vicinity that does helis of any kind, I have been pretty much self-taught. Lots of research, reading, blogs and trial and error experiences. So, I can use all the help, advice I can get, even if it means only having a venue to vent frustrations once in a while. On a side note-- Iv'e tried parts from many different brands and for the money, I do like the Copter-X Black Angel. The basisc frame is the same as about any other but rotor heads (especially the FBL series seems to be more stout than most of the others without paying an arm and leg for them. And for someone that has had a great propensity to re-kit helis (at least until recently) that is quite important. At least my wallet thinks so. Wink

waleeed00 · Charging Joined: 14 Mar 2016 Posts: 1

Now my 5 blade has Align 3G on it, and has never been tried without it. Howeveer I have a theory based on all this, and that is that a 4 blade head does NOT need electronics support because the blades are exactly 90 degrees apart, so you just need to set up the phasing mechanically in the usual way and then each blade automatically handles the dreaded precession that needs electronics if you use a 3 or 5 or 6 blade head.

tombo242 · Posted: Mon Mar 14, 2016 9:05 pm Post subject:

Hi waleeed,

You can fly this without a flybar less controller, but you may well need to flatten the pitch curve some and use a little expo. The tail will need strong authority as well.

Recommended is to set one blade in line with the tail and then slide the linkage to give 0º offset.

Could be that Burgess will follow with more advice.

Good luck with the project,

Tom.