rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 590 ONLINE 29 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]2969 viewsPOST REPLY
GrandRC . CanoMod . Futaba-RC

.
.
Century Hawk - Falcon - Raven - Predator > Falcon 50 SE II Tail Modification
 
 
Lift
Elite Veteran
Location: Houston, TX

The new Falcon 50 SE II is a fantastic heli. I have now burned close to 4 gallons through it and the OS .50 SX-H is starting to come alive. I have been working on various combinations of paddles, tail setups, mufflers, and radio tuning till I have it the way I like. Although, there is one problem that I have exhausted to no avail so I have a modification that I would like to propose to you guys.

I have been having problems getting enough travel on the Falcon 50 SE II tail for Nose-Left piroettes in FF. Let me emphasize Forward Flight. Please do not respond and say that your Falcon piros real fast to the left if you are referring to a stationary piro. No matter how well you center, set at 90, play with lengths out on the servo horn, transmitter ATVs, ect. you WILL NOT get the Falcon tail to provide enough travel to piro the heli NOSE-LEFT in FF.

I use the Futaba GY 401 w/9253 digital servo which uses the "Limit" pot to set the travel for the rudder servo. What happens is once you set the gyro "Limit" pot to clear the tail rotor bellcrank moun you end up with little to no tail rotor pitch for NOSE LEFT. No matter what you do to the piro rate(ATV to 150) it still doesn't have enough pitch to piro the Falcon in FF. Why? Because the Limit is just that. A LIMIT and it will not travel beyond that point.

Just try it.
Method 1)
Go into a 540+ stall turn and begin the piro on you way up NOSE LEFT. It will turn the heli 90 degrees to the left and STALL until the forward speed dips to a level where the counter torque of the main blades begin to bring it around.
Method 2)
Go into level FF at average speed now input full Left Rudder. You will see the heli turn 90 degrees and STALL until the same as in method 1 above occurs.
After all, on a clockwise rotating head NOSE LEFT releases the torque of the engine/blades. So, unless your tail blades have enough pitch to over drive the existing counter torque of the blades/engine then the heli will STALL until the forward speed dips to a level low enough for it to swing around. I tried everything from different blades to countless configuration settings to no avail.

Now, the problem in the tail is the pitch fork and the geometry as to how it attaches to the blade grip. The fork is straight, i.e. 90 degrees to the tail rotor shaft. If you look at it compared to other pitch forks you will see this right away. The fork WILL hit the tail rotor bell crank unless you limit the travel. This reduces the overall travel of the 401 since you do not have independent travel adjustment on it like you do the GY 502 & 601. Those gyros let you set the end points for left and right independently. Although, I am NOT in the market for a new gyro so I decided to stick with the 401. Anyhow, here is a pic of the Falcon SE II's tail from Century's site(Geez, nice Carbon Fiber boom. How come my kit didn't include one ) :


Now, look at the Raptor 60 tail rotor pitch fork. See how it is swept forward. Since I can now set the limit for NOSE RIGHT at a much higher value I can also get more NOSE LEFT throw and thus more tail pitch.



As I mentioned I installed what you see above on the Falcon SE tail since both the Raptor 60 and Falcon SE use 5mm tail shafts. Namely I used the following Raptor 60 parts:
1) PV0136 Pitch slider. $9.90
2) PV0151 Tail Rotor Hub $6.99
3) PV0148 Tail Rotor Grips $5.99
4) PV0200 Tail Rotor Bearings (d5 x D10 x 4) $10.39

All this is a bolt and fly setup. It creates a more symetrical pitch range in the tail rotor and TOTALLY solves the problem of NOSE LEFT stalls. I am now able to do a NOSE LEFT piro in FFF and the stall turns can be started at any point in the verticle line. I was leary to do much backwards flight with the tail not responding properly but now it is AWESOME.

This has been my only real gripe on the Falcon. And if that is all then I am way ahead compared to the issues of other well known 50 helis. This is one great flying heli that I intend on pushing to the limits of my ablility gallon after gallon. Glad to resolve my final issue.

Now, where is that drum of fuel??????
07-22-2002 Over year old.
 
 
Isaac F
Key Veteran
Location: Panama Republic of Panama

Hello Alexander, Why you have to change the Tail Rotor Grips and Tail Rotor Hub????

Why dont you use the Factory Falcon Tail Rotor Grips/Tail Rotor Hub with the Raptor Pitch Slider???


Isaac
07-22-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Pitch Fork & Grips

Guys,
I tried to use as much Falcon stuff as possible but the stock Falcon pitch fork and grips have an offset built into them. Actually, the lower one is the R50 tail rotor case. It is hard to tell but if you use the Raptor 60 pitch fork you MUST use the Raptor 60 grips. And, if you use the Raptor 60 grips you MUST use the Raptor 60 hub and bearings.

So, it is an all or nothing deal. If I remember correctly the Falcon uses two different size radial bearings in each grip and neither one of the is the d5 x D10 x 4mm size that the R60 uses.

I hope to get some pics of my setup soon to share. I did use the upgrade aluminum pitch fork like this but the stock plastic one is fine:


I will say that the thrust bearings in the tail are not really that necessary. They will keep the tail tighter for a longer period of time but I don't mind replacing the radial bearings if they get sloppy. All I can say is that if you do this mod you will IMMEDIATELY notice the improved feel and response.
07-22-2002 Over year old.
 
 
gforce
Veteran
Location: Jacksonville FL

I am going to convert mine also. I just got done building the T/R on my falcon, and that hitting, binding thing bugged me to. Thanks for the info Payton.
07-23-2002 Over year old.
 
 
voclain
Senior Heliman
Location: Houma, LA

Payton.....

....I have the 502 gyro,,,,,so you are saying that with this gyro, I will be able to program the nose left problem out by just putting in more throw on that side of the gyro????

Kirk
07-23-2002 Over year old.
HOMEPAGE  
 
 
jimmyhua
Veteran
Location: Guam

Alternative to costly mod.

Lift,

Okay, there is another way to do this.

You can force fit some fuel tubing over the hub and make a stopper so the slider won't go past a certain point.

Then you can set your GY401 so that it binds a little (or alot).

This should give you ALOT of left authority.

If you want to get rid of the binding, you can also try the following mod (which I did on my Hawk).

If you notice the triple BB blade grips actually have TWO holes for the ball links. Use the other hole! It will seem at first that you won't have enough left authority after doing this, but now, the center point will be very close to the hover point, and the throws on the servo arm will be very symmetrical.

You'll probably get less of a left pyro rate this way though, but you get rid of the binding this way.

You could alternatively fill those two holes up with epoxy, and drill a new hole for the ball link in the proper location. This will get rid of the binding and give you alot of throws. You basically want the new hole to be right smack in the middle of those two holes and slightly closer to the blades (or closer to where the BBs are at). Notice how, the slider to ball link arches open wide? It needs to be squared. Hopefully you know what I'm talking about.
07-23-2002 Over year old.
 
 
jimmyhua
Veteran
Location: Guam

volcain

Although I'm not Payton, I'll answer for him.

With a programmable gyro, you can do all sorts of wonderful things.

And the above problem he mentions suddenly becomes a non-issue!

Just make sure the slider doesn't bind at the extremes.

Here's the test. Push full left rudder, spin the tail and make sure it spins freely. Push full right rudder, spin the tail and make sure it spins freely.

If the pitch slider hits the bell-crank in flight, you are gonna have to land w/out a tail. Been there, done that!



Jimmy
07-23-2002 Over year old.
 
 
voclain
Senior Heliman
Location: Houma, LA

OUCH!!!!

That must have been pretty.......

Kirk
07-23-2002 Over year old.
HOMEPAGE  
 
 
Bigfish
Senior Heliman
Location: Royal Oak, Michigan

Tail Slider

I was having the same problem with tail pitch travel when I first built my Hawk SE so I used a JR Ergo fork ................

I have just rebuilt the tail after a little accident and ended up using the standard Century fork.

I put a 3mm length of fuel tube on the gearbox end of the shaft to stop the fork hitting the bell crank pivot. I also found that you can get a respectable amount of blade pitch for left and right if you use the outer ball mounting hole in the grips (note that Falcon picture shows the ball in the inner position closest to the gearbox)

BF.
07-23-2002 Over year old.
HOMEPAGE  
 
 
kevlar11
Senior Heliman
Location: Edmonton

Tail Pitch

aaah has this has been done by Century?
http://homepage.mac.com/kevlar11/PhotoAlbum4.html
They added about 2~3 mm space on to the pitch plate, this would give more
left no?
KD
07-23-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Grip ball holes

Hey guys! Thanks for the responses. Let me catch up.

Kirk,
Yes, from what I understand the 502 & 601 have independent end point adjustments. So, you can use that feature to create more pitch for Left rudder. Wish I had a 502!

Jimmyhua,
I have heard of using the fuel tubing to prevent the pitch slider from contacting the bellcrank. Although, that is what the Limit function is designed to be used for on the 401. I had the Limit set all the way right up till the pitch slider was about 1mm from contacting the bell crank but on the opposite side of the travel it was only giving me marginal blade pitch.
Regarding the holes I did consider that but again it threw the symetry off in the opposite direction. Century probably has the two holes made like that so that if someone flipped the tail rotor assembly to the left hand side for a scale project they could get the necessary pitch in the other direction. I decided to stay away from that one as well. Good idea though!

Bigfish,
Yup, there are alot of options out there to give you the pitch you want in either direction. Unfortunately it is all to the left or all to the right for the Century tail grips & pitch fork. But, the holes just shift the problem from one side to the other by the time you get everything re-centered. Also, the bellcrank abandones a 90 degree angle.

Kevlar11,
I got my kit in the middle of May and it has the same pitch slide that your has. So, from what I can tell this has not been addressed by Century. It wouldn't take much to alter to get it more symetrical as far as the throws are concerned. All they would have to do is modify the gips to use a single hole centered in the blade grips like JimmyHua proposed.

I have now got 4 gallons on the heli. Not alot of time but I think the Falcon SE is an EXCELLENT flier. I think that Century could make some more modifications to a few areas like the tail, the boom clamp(move boom supports to side mount so CF pushrods clear), improved dampners(get soft pretty fast), a tad more rigid canopy, loose the current fuel tank plug setup in favor of what other helis like X-Cell, TT, Hirobo, and the like. Basically, some of these issues are just carry-overs from prior products. Century has done a great job in the scale area. I think with the Predator 60 coming that they might have a new focus on the Sport/3D aspect. So far they have been doing a pretty darn good job in refining the Hawk and the Falcon. We will see!
07-23-2002 Over year old.
 
 
oldfart
Elite Veteran
Location: Vancouver, Canada

Tail rotor/gyro set up

Lift,

I am using the stock set up and have a lot of power to the left and right. for sidways FF flight. So obviously I have been grinding my brain to figure what may be different, and again the only thing I can think of other then that you can easily increase the power of any tail rotor by increasing the length of the tail rotor blades (e.g. 95mm) and optimizing the gyro system to the mechanical set up. This can only happen if your mechanical set up is set up to travel the same both side of center. If you use the gyro end point adjustment and TX rudder trims you may not be so set up mechanically (at the servo arm). DO NOT use the "triple beep" method of trimming initially for both modes in the 401 as it will be very easy to end up with a non-balanced mechanical relationship.

To insure a working "egual travel" (power) mechanical set up:
1 - check what tail rotor pitch settings are used in the hover (on the bench, put the gyro into the YAW RATE mode (non HH), fold the blades towards each other and measure the space between them (this will be 25 to 30mm depending on the RPM you hover at, blades used etc) . This establishes a reference for the pitch required to counter torque.
2 - INSURE rudder ATV settings in the TX are the same on both ends e.g. 100/100.
3 - INSURE the rudder trim is centered at "0" and there is NO mixing.
4 - Now set the rudder servo arm onto the servo so that it is at 90 degrees to the pushrod and in the middle of its travel range. Now ONLY adjust the control rod to the length that required to hold the tail rotor in the same position as in step #1.
5 - Now take the heli into the hover in yaw rate mode and adjust to counter any minor yaw drifting that may occur by ONLY adjusting the length of the pushrod mechanically. DO NOT use your rudder trim on the TX.
6 - Now put it in HH mode and NOW USE the TX trim to trim out any yaw in that mode (this should now only require less then 10 points) and your gyro end point adjustment to set the no binding points.

Now when you check your servo/system travel you will find the same servo travel in both direction from center.

Phil
07-23-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Ditto......

Phil,
Hate to say this but been there, done that. I couldn't get it to work out using the above common procedures. I don't know. I just couldn't get enough throw.

When you say your heli piro fine in FF are you referring to a complete 360 degree piro while the heli is moving forward? I mean at a decent speed?

Reason I am asking is because if I was just moving around slow and low it was fine. But if I put the bird into say 30 mph flight and tried to get it to piro it would flat out stall. Stall turns were worse.

The average sport pilot may never push the tail around enough to notice this but if you intend on doing 3D it becomes apparent IMMEDIATELY. I mean you can visibly see that their is little to no pitch on the bench for left rudder. But right rudder easily creates 45 degrees of pitch. Look at yours and please tell us how much pitch angle you are getting on the bench.
07-23-2002 Over year old.
 
 
gforce
Veteran
Location: Jacksonville FL

Do the stock Falcon vertical fin slow down the piro rate. It does not look like much air can flow through it. It looks like it would give resistance to a piro while in FF.
07-23-2002 Over year old.
 
 
jugger18
Heliman
Location: Madison WI

Calrification

When you say you had it set to 90 degrees i hope you mean the servo and not the tail....The tail piece should be offset...around 80 degrees or so
07-23-2002 Over year old.
HOMEPAGE  
 
 
Lift
Elite Veteran
Location: Houston, TX

Falcon Tail Fins

Gforce,
Yes the stock tail fins do hinder piro performance. You can open them up by clearing out the square indentions or replace them with a set of carbon fiber fins that fit the X-Cell Fury like I did. Mr. Carbon makes them.

You will have to enlarge the bolt holes and use some spacers on the verticle tail fin to get it to stand off the tail case some. But, it looks very nice and provides enough clearance to run 97mm Model Sport CF tailblades with 3/4" room to spare!

I also added some 3/8" rubber grommets in place of the plastic spacer that go between the lower frame and the rear landing gear struts to "tilt" the heli up in the rear when sitting on the ground. It actually is unnoticeable and keeps the tail out of the dirt on those autos!!
07-23-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Clarification

Jugger18,
Yes, you are correct. The tail rotor bell crank is NOT a 90 degree bellcrank.
07-23-2002 Over year old.
 
 
gforce
Veteran
Location: Jacksonville FL

Payton, those are some good ideas.

I just put a fury vert fin on the Falcon. That does look like it will work better.

Also, I just set the limit on my gy401 with the Falcon and holding it 1mm away from where the slider would hit the pivot point the overall travel is, well let's just say, "less than the full amount possible." Looks like about 70% of the full travel is used to me. The limit setting on my 401 is less than 80%. If the pitch slider were made properly (like the raptor one) I could easily get 4 or 5mm more travel out of it on both sides. I ordered the parts for the conversion from GR8 lakes, and I know it will make a huge difference. Thanks for all the tips!!!

I can't believe Century sell this Heli like this. They need to make a change in the design. It needs it, if you ask me.

So the ultimate setup on this Falcon t/r is:

95mm blades
3D carbon fin
Raptor 60 tail pitch slider, grips, bearings, hub
07-23-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Easy big fella......

GForce and all,
I want to say that while I think the stock design is not optimal I do want to add that this mod may not be for everyone. I HIGHLY recommend that you build the heli stock with the exception of the personal stuff like start shaft adapter, paint/decals, etc. Then after you get a feel for what you have make the necessary changes. Not all setups are the same and what I like may be uncomfortable to you.

I do know that the tail will feel akward(sp?) if you are looking to do aerobatics and 3D. If this is your intentions then consider the modification. If not, then you will be fine with the stock tail system.

As far as the "Ultimate" tail setup I am not sure that I would go that far. This is what works for me and since Mark Ryder is kind enough to provide this forum I would be a fool to not share it.

So, build it stock. Fly it and then start working out the little demons that all helis have.
07-23-2002 Over year old.
 
 
Lift
Elite Veteran
Location: Houston, TX

Pics.

Glenn,
BTW, great looking Fury Extreme you got there. But most of all what a great looking FAMILY! You are blessed dude!
07-23-2002 Over year old.
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]2969 viewsPOST REPLY
A Main Hobbies . Boca Bearings . Modefo's RC Helicopters

.
.
Century Hawk - Falcon - Raven - Predator > Falcon 50 SE II Tail Modification
  UPDATE SCREEN   PRINT TOPIC Advertisers 

Subscribe to This Topic

Saturday, October 11 - 10:55 pm - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie