4 bladed tail for the Swift 16 !

[Spidious]

Well I have been working on my 4 bladed tail rotor for my Swift. So far it is working out better than I planned. Except for one small snag. I need a double ball in order to connect the two tail blade assembly together. It will need to be able to screw into the blade grip like the original. Whether it is by using four balls and two screws. Or if somebody actually makes a double ball screw I will try that. But below are some pictures of it so far.
I have not notched the shaft yet for the set screws, or drilled the hole for the gear drive yet. I need to get it set up before I figure those dimensions.

[Spidious]

I might of found some 3mm shaft balls that will work with my hardened screws. I will stop at Advantage Hobby tomorrow on the way home and keep my fingers crossed !

[laughingstill]

That was fast! When are you going to test it?

[Spidious]

May be a while I still need to get the balls to allow it to pivot correctly, Notch the shafts for the hub screws and drill the holes and cut the shaft length down. Once I get all of that done.
I may not test it till I get the aluminum tail assembly. Or I may, since I am running a low head speed anyways.
If it works as good as I think it will. It should really look nice on the Agusta A109 Coast guard version with a four bladed head !

[electrosphere]

just wondering if that mechanism will work?
i noticed based on the picture.. one of your tail grip is set up on the leading edge where as on the other tail grip is set at the trailing edge..
for example, if the first set of blades goes to -15' to turn right will the other set of blades goes + 15' and cancelled the effect of changing pitch??

[Fred Bronk]

Very nice work Spidey, but he is right. The blades will work against each other as setup. Flipping one set of holders should work fine though. You won't need much pitch either.

I think the dual ball setup as you have it will work, but get a shoulder bolt under those balls :D

FB

[electrosphere]

I'm also setting one up for a 450.. my plan is to use dual pitch plate, one with short linkage which connect to the inner tail rotor grip, and one with longer lingkage which connect to the outer tail rotor grip. by doing that there's no grip flip between the two system.. hopefully my suggestion will be usefull... photos coming soon...

[Spidious]

Yes I know they are working against each other. I just wanted to see just what else I need. When I set it up they will be closer tot eh tail on a AH-64 then at the 70° they are at now.

[Greybird]

Gadget had trouble with leading edge control. Make them all trailing.(and test it with plastic blades)

[tioli]

I was thinking about a 4 blade tail for my mini titan and wondered aloud with my friend whether you make a fake set...have two regularly pitching blades, and two that just look pretty.

[Super_Hornet]

For cascade type of tail rotor, here is how I done it:
http://www.rcgroups.com/forums/showthread.php?t=784069&highlight=cascade

http://static.rcgroups.com/forums/attachments/2/7/0/6/9/a1608230-255-DSCF0012_WithTag_resize.jpg

Remember that the scale heli that I use in those pictures are MD500E...thus the tail is on the left and spin downward like in real MD500E.

SH

[Spidious]

Well it was a good idea. But I can't figure out how to get the blades at about a 90° with out having the linkages bind up.
Does anybody make a 4 tail blade for a 5mm shaft ?

Or can draw up a 4 bladed hub that would work on the Swift shaft assembly that I can have somebody make ?

[Fred Bronk]

http://www.heli-world.com/searchresult.aspx?categoryid=256

http://www.starwoodmodels.com/products/of/multitails.php

[Spidious]

I figured somebody would know. Thanks Fred
The heli-world looks reasonable for $120, but they have no specs on what it even fits ? I have emailed them.
And the other for $700, I don't think so !

[Greybird]

What about if you re-built the slider with a star servo wheel? You could space out 4 ball links with 3mm rod and secure with bolts. 2 longer, 2 shorter. Here is a quick mock-up. the between ball link distance is very close. I don't know if the 2 heavier bolts would cause extreme vibration? ( This is 2mm bolts from Eco stuff. This is very similar to the Eco design, except for the 2 longer bolts, but it will not bend at the extreme like the Eco does. My main worry would be vibration).

[Spidious]

Hey good idea. I will check it out later...

[Greybird]

It is not a good idea until it actually works....

[Spidious]

Great idea Greybird !


Had one laying around, trimmed the center part.
Took a broken swift slider apart.
Screwed it on, and except for it being a bit to small across 24mm.
I need to find one that has the distance of 30mm from hole to hole.
And it will work perfectly !
And I can get it at 90° !
So now I need to find a cross with the 30mm across and then drill the holes in the shaft to test it.

[Spidious]

Found the one I need. It is 38mm on the outside dimensions.

FUTFSH6X

But of course it is out of stock !
I want the cross style to allow a little flex to the movement.

[Greybird]

Looking good Spidi. Some tweaking here and there and you might have it. Maybe spin it up in a drill press to check for smoothness when you get a working version?

[Spidious]

Matter of fact. I still have the drill sitting next to me :)

[Greybird]

The Futaba one actually has a ridge on the one side that sits on the bearing perfect. I have a couple of those arms. Pm me your address.. Wait a second, I'll send one.. I might have to try this also. :D

[Greybird]

It's in the mailbox. It will go out in the AM.

[Super_Hornet]

The slider using servo horn will work IF it does not hit the pitch arm or the surrounding.

I done that (using servo) during last time I build an inline 4 bladed tail rotor for my TRex450 in my 6 bladed head. The problem for TRex450 size is that the tail area quite small and the servo horn (HS-56) hit the surrounding when applying pitch on the end side. I end up trimming some parts off.

SH

[Greybird]

You are right SH, that might need to be spaced with a washer.

[Spidious]

I figured I might need a spacer for extra clearance. But I will figure that out after I get the servo cross from Greybird.
Did some more playing around with the shaft. The end lines up perfect with the lock screw in the hub. The hole that needs to be drilled. lines up at the center of the indention of the shaft. I will need to trim off about 40mm off of the end of the shaft. So far it is working out pretty darn good !

[Super_Hornet]

If u are building for AH-64 or MD500E, do remember that both have the upper blades "lead" the bottom blades. MD500E has its tail rotor spin downward while AH-64 tail blades spin upward.

SH

[Spidious]

I will have them both spin upward into the air stream.
Very good chance I will end up buying the Agusta A109.
The AH-64 looks fantastic, but I just am not sure how well I could build it. Maybe someday somebody can build them and then sell them ? Or at least have it almost assembled.
And they will be running at a 90° angle to each other, what do you mean the upper blade leads the lower blade ?

[Super_Hornet]

I thought A109 only have 2 blades on the tail? They have 4?

As for the blade "lead".. Take a look at the blades between the upper pair and the lower pair in AH-64/MD500E. Look at the side where the angle is smaller...that is 55 for AH-64. Since AH-64 spin upward, the upper blades is in front/lead the lower blades if u trace it based on the spinning direction.

EDIT: What u are doing right now is like 2 pairs of blades arrange in a "cascade" manner. This configuration is like AH-64, some MD500E with 4 blades tail and AH-1Z. Tail rotor for UH-60, Lynx are something like multibladed main rotor (inline type).

SH

[Greybird]

Looks like 2 blades on this one. The A109 is a good looking machine. I still think the 4 blade tail would look great on yours Spidi.

[Spidious]

Maybe not on full sized A109's.
But if I go to the 4 bladed head I will loose a lot of tail authority due to the lower head speed. So I will make it up with tail surface area.
Plus it will look nice with the four blade head !

You know the more I look at this copter, the more I like it. Below is my computer background...

[Greybird]

You know, the Century kit looks almost as nice as the real one...

[Greybird]

Spidi, The Futaba cross arm rides on that bearing perfect. For added clearance, Maybe you need these.(flathead socket screws) Here is a 2mm screw countersunk. I think 2mm is plenty. My Logo 10 uses 2mm bolts on the ball links. You will not get 3mm in that servo arm. I bent and twisted this piece. It seems pretty tough.

[Spidious]

Hey Greybird, got the cross today.
THANKS ! :D

Drilled out the center so I could put it on the slider all the way. Did a spin up and it should work pretty good. Will test it on the copter this week end maybe ?

http://www.vimeo.com/1792053

[laughingstill]

Looks good!

[Lynxman]

If you want more tail authority you could increase the tail rotor rpm instead. Isn't the 620 tail drive pulley bigger? That will increase the tail rotor rpm a little.

[DSB11]

Does this can improve the efficiency of bladed tail ?

[Greybird]

Spidi, Can you post another close-up? Does it have enough clearance for the lever to snap on the ball? I have all the parts to build one, except, I need some blade grip bearings. Before attaching it to a heli, maybe grab the slider and test as fast as you can power it, at the limits each way? Put some strain on the parts.

[Greybird]

Spidious, I have this one. DSB11 and Lynxman. Authority, Efficiency, whatever. It Just looks COOL!!!

[Spidious]

Don't know if the 620 pulley is bigger or even fits.
But as far as looks, I don't think you can beat a 4 bladed tail !
Will look even better when I get my white fiberglass blades with the red stripes on it !
Oh if you do the same, be sure and check the weight of the blades and put them on the same hub. You would be surprised just how much different a tail blade can weigh.

[Greybird]

Spidious, I did not think to try that end of the servo arm. It fits even better. Rides the bearing perfect. Better clearance too. Yours looks good. I measured the Century rods. 2.22mm. 2.5mm hexheads measure 2.41mm. They thread right into Century ball links. ( I tried one) I can send you some if you want. I have metric and standard nuts. Nothing fits those Century rods.

[Spidious]

Yeah why does Century do these stupid dimensions problems ?
Gadget and his cnc heads, and me trying to find nuts that will fit on their rods. Which I have had no luck doing.
I do need to find 8 nuts and four shafts that will fit into the Swift links, to be safer than just them threaded into the plate. But for test purposes today it should be OK.
I lowered the head speed all the way down to 1400 rpm, the lowest I can set it is 1300 rpm with the Castle Link and the 6S battery. If I go with a 5S or 4S battery I can crank it down even further. Which I may have to do with the four balded head.
So if anybody is still wondering what a 4 bladed tail looks like on the Swift 16 look below !

[Spidious]

Well went ahead and did the first test flight tonight.
Turned down the head rpm to 1400, and it still has fantastic tail control for scale flying. Even with that low a head speed !
I do not recommend it for 3D flying with a high head speed. It may work, But I don't want to try it out.
So far the items needed to build your own are.

1) T-Rex 450 main shaft # HS1011 : drill the hole for the gear drive into the center indented part of the shaft. The outside hub is secured at the hole that is already drilled in the end of the shaft. File a flat spot on the shaft for the other hub to lock in in position, to keep the inside hub from rotating. The long end of the shaft is the end the hubs go on. So everything will be in the proper alignment.

2) Two Swift 16 tail rotor hubs # CNE540 x 2

3) Four blades, either the Swift plastic # CNE541 x 2 or your choice of others. If you use other blades, cf or fiberglass. Be sure you check the weight and put them on the same hub !

4) Two long and two short Century links # CNE546 & two link rods that are 10mm and two link rods that are 15mm long. Better would be to use slightly longer rods and nuts on each side of the Futaba servo cross.

5) Futaba servo cross with a 13mm hole from the center of it. Tap the hole for the Century link rods, or use longer rods and nuts on each side to lock them in place.

6) Swift 16 tail pitch slider # CNE537. Remove the pitch arm assembly. Then using a 13/62" drill bit drill thru the center of it and clean it up till the slider brass piece will screw into it. Be careful. If the hole is to small it will pull the threads on the brass slider and ruin it. When it will screw on easily, you have it sized right.

7) Eight bearings for the tail blade grips # HS1031 x 2

Just look at the pictures and you can figure it out. I take no responsibility of what you do as far as building or installing it on your helicopter. I do recommend using a aluminum tail transmission gear box.


http://www.vimeo.com/1799291

[Fred Bronk]

:confused:

OK, but why the offset? Will you use it on the Apache? If so the blades are not 90* from each other.

Other multi bladed TR are in line. If you want more authority, just use longer blades?

Great work though.

[Spidious]

Just something about a 4 bladed tail rotor...
Just come up with these ideas in my head sometimes and have to do it, or it will drive me nuts.
I may buy a actual in line one later, but till then it looks pretty darn cool.
As far as the AH-64, I am not sure my building skills would suit the helicopter.

[Fred Bronk]

If you just want a 4 blade TR then use a 4 bladed head from the T450.

FB

[Spidious]

Thought of that also.
But they would cost almost the same as a 4 bladed tail rotor. Which I am still waiting for information from a company that sells them.
For the dimensions of it !

http://www.heli-world.com/detail.aspx?ID=4137

[Spidious]

Ended up calling them on the 4 bladed tail. It is made for a 3mm shaft. And she thinks 30 sized tail blades. I really don't think it would be able to take the swift blades ? I could see enlarging the hole to 5mm, but not actually having one in my had or a picture of a actual 4 bladed tail rotor head. I can't be sure.

[Spidious]

Well actually flew it today with the 4 bladed tail.
Forward flight, hard turns, simple scale flying..
Works fantastic !

Head speed = 1500 at 0-98% 1600 at 99-100%
Battery = Rhino 4900 6S
3123 out of 4900 used = 64%
12 minutes of flying time = 250.25 p/m
Should be able to fly 15 minutes and use 80% of the battery !

I also tried some silicon lube on the tail belt and readjusted the gear lash, it runs a lot quieter now !

[Greybird]

What motor and pinion? How are you getting the headspeed that low on 6S?

[Spidious]

1100 Z motor
9t pinion
CC speed controller set in rpm

################################################## #####
# Castle Link Data File
# Created: Sunday, October 05, 2008
# Do Not Edit This File By Hand
################################################## #####
Brake Strength: 0
Brake Delay: 1 sec
Brake Ramp: Super Slow
Current Limiting: Disabled
Cutoff Voltage: 180
Cutoff Type: Soft Cutoff
Motor Start Power: 59
Motor Timing: 5
Direction: Reverse
PWM Rate: 12 Khz (*)
Hex55: 85
Vehicle Type: Helicopter
Throttle Type: Governor Mode
Throttle Response: 5
Governor Gain: 2
Initial Spool-Up Rate: 5
Head Speed Change Rate: 5
Auto Rotate Enabled: True
Governor Mode Type: Fixed
Vehicle Setup - Battery Type: LiPo
Vehicle Setup - Number of Cells: 6
Vehicle Setup - Battery Voltage: 22.2000
Vehicle Setup - Gear Ratio: 10.645
Vehicle Setup - Motor Kv: 1100
Vehicle Setup - Motor Number of Poles: 8
Desired Head Speed 1: 1503
Desired Head Speed 2: 1503
Desired Head Speed 3: 1603

Dark horse set up (http://dhrc.rchomepage.com/calc.htm?kv=1100&voltage=22.2&pinion=9&gearTeeth=96&drag=.66&dia=1200&mah=4900&AUW=2350&amps=15.65&packv=22.20&time=12.02&drain=.64&redButton=B-Restore3&LastItem=drain&)

After a 12 minute flight.
Speed controller cool
motor cool
battery cool... !

It actually can go as low as 1300 rpm. But I think that may be a little to low !
It can go as high as 2200. Dark Horse set up 2200 rpm (http://dhrc.rchomepage.com/calc.htm?kv=1100&voltage=22.2&pinion=9&gearTeeth=96&drag=.97&dia=1200&mah=4900&AUW=2350&amps=23.52&packv=22.20&time=8.75&drain=.70&redButton=B-Restore3&LastItem=drain&) But boy does it eat the battery up and is extremely fast flying ! :eek:

If I go with the 4 bladed head, I will have to either go with a 5S or 4S battery to get a head speed of around 1100 ?

Dark Horse set up 1100 rpm (http://dhrc.rchomepage.com/calc.htm?kv=1100&voltage=14.8&pinion=9&gearTeeth=96&drag=.73&dia=1200&mah=5000&AUW=2350&amps=51.09&packv=14.80&time=4.11&drain=.70&redButton=B-Restore3&LastItem=drag&)

I will probably up it back up to 1600 across the board, as it handles better !

[Greybird]

Which CC speed controller do you have? I assumed they would get hot, dialing down the rpm that much.

[Spidious]

It is a phoenix 60 and it actually doesn't get hot at all.....

p.s. Forgot to mention that it did get very hot, motor/battery/esc at 2200 rpm ! And was it loud and scary !

[Dogwoodtheone]

Nice work Spidi, this thread will come in very handy when I do my Apache build :)