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Thunder Power RC . Real Raptors . Mikado Modellhubschrauber

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Century Hawk - Falcon - Raven - Predator > what pitch do you run ??
 
 
the Wasp
rrProfessor
Location: Vt

Guys,,, what pitch do you run on your Century helis ??,,, if you run a max of 9 degrees of pitch at full stick with 15% nitro on a Falcon and then your change to 30% nitro you must be able to pull 10 degrees of pitch,,,,, But !!, I run an OS 46, and an OS 50 must be able to pull more pitch, even if the fuel is the 15% ??, right ??

I'm running 10 degrees of pitch on my Falcon with an OS 46 burning 15% C-Power, and I thing it's to much pitch, it's OK for climb outs, and flying, but when I fly straight up or go to loop it over I lose head speed,,, so the week end I will lower the pitch to 9 degrees and see what happens,,, now on my Hawk SE V2 with a OS32 ABC 15%, 9 degrees was great for looping and flying straight up !!

tell us what you run for pitch !!

Jim
08-06-2002 Over year old.
 
 
jimmyhua
Veteran
Location: Guam

Sorry, I'm still in the process of piecing together my Falcon SEv2.

On my Hawk SE. I run +/- 7.5 degrees pitch in 3D mode.

The headspeed actually increases on a straight climbout, however, on stationary flips and rolls, the headspeed slows down greatly. I plan on experimenting with cyclic->throttle mixing to solve this problem.

On smooth forward flight loops, rolls and climbouts, I can run 8.5 degrees pitch w/out bogging on the Hawk SE. The headspeed does slow down a bit, but not really noticeable.

Alexander, I did a post on my Falcon build, and found I have 6+ degrees of cyclic authority, and +/- 17 degrees of collective authority. It's stock, only thing I did to get the 17 degrees is take out the anti-rotation bracket. This thing will roll/flip really really really fast with the stock paddles. +4 w/out flybar weights have been plenty for me.

Wasp, on your Falcon, you're either running too rich, or your muffler is too restrictive, or your loops are so tight that you are actually flipping and not looping. Given the same muffler, the power difference between the OS46 (1.62 bhp) and 50 (1.8 bhp) is like 11%. So if you get the 50, get a good muffler/tuned pipe to go with it. What I like about the 50 is the practical rpm range of 2,000-20,000rpm vs. the 46 which is only 2,000-17,000rpm.

P.S. I know some guys are able to run +/-9 on their Hawk SEs. But my needle setting is in the conservatively rich side still.

08-06-2002 Over year old.
 
 
the Wasp
rrProfessor
Location: Vt

my problem

well, my muffler was lose so I thought I would look at the piston through the exhaust port, and of course my piston just has to be scored,,, I was so careful to brake-in this motor right, it stalled once in a hover, but it did not rev up as it would have if it leand-out, it just stalled,,, Great Planes said that most likely they would replace it because I received it only 11 days ago (as of today), so now I will have to wait 3 or 4 weeks until I get my motor back ,,

as of my pitch, I think I had to much pitch, so when I get it back in the air I will try it at 9 degrees !!

thanks guys, Jim
08-07-2002 Over year old.
 
 
willie evans
Veteran
Location: Alberta, Canada

I think the blades stall at more than12 degrees other than straight flight I run +9 -9 to a total of 14 with that and a tt36 motor theres no slow down of head speed I had os 32 but had to run lower pitch to keep head speed up.
08-07-2002 Over year old.
 
 
blazen
Senior Heliman
Location: California

To much pitch

I do believe that 17 degrees (Collective + Cyclic) is quite excessive. Generally you should try not to exceed 15 degrees of Blade pitch (Collective + Cyclic) . At about 15 degrees the Blade starts to produce more drag then lift and progressively stalls.

If you are not getting the results you need at 15 degrees its time to either increases blade area or rotor speed.

73’s
Blazen
08-07-2002 Over year old.
 
 
kevlar11
Senior Heliman
Location: Edmonton

Pitch

Hi
I run+10-10 on my Faconv2 with a O.S. 50 on 15%
KD
08-07-2002 Over year old.
 
 
jimmyhua
Veteran
Location: Guam

follow-ups

Blazen, Well, I plan to run +/-10 degrees pitch on my FalconSEv2 (maybe even a +/-9). However, I think the +17 might come in handy for a drag racing set-up.

Alexander, you might want to ping oldfart on what kind of mixing configurations you can do with the Falcon. You can actually flip the washout assembly, and get different ratios, I think. For me, strictly following the instructions have been good enough. The feel is pretty solid. And yes, I did see some cyclic binding at the corners. It's rubbing against the plastic in the swashplate assembly. Is it safe to assume that this extra plastic will eventually rub off, and the cyclic binding at the corners will reduce?

theWasp, I am glad you solved your lack of available pitch problem. The engine was scored and didn't produce the necessary power.

I had a great day of heli flying today. My friend even took some pictures. I'll post when the pictures become available.
Anyways, I hope the pictures come out clear, my friend had his camera in manual mode and had to setup everything as I flew... duh.


Jimmy
08-08-2002 Over year old.
 
 
blazen
Senior Heliman
Location: California

Quote
>>Blazen, Well, I plan to run +/-10 degrees pitch on my FalconSEv2 (maybe even a +/-9). However, I think the +17 might come in handy for a drag racing set-up.<<

Jimmy
That sounds about right to me.

I had/have a schluter JR 50 that seemed unbeatable in a drag race. I don’t recall what the top end pitch was. But I can tell you that I would wind it up past redline on the start line. That rotor was spinning at 2500 rpm + I know that sounds really high (people where ducking for cover because it sounded like it was going to explode) but the JR50 gearing was set to run at 2000 to 2100 head speed stock !! This was one stout little bird !!
In a drag race I would loss 1000 rpm by the time I hit the finish line.


73's
Blazen
08-08-2002 Over year old.
 
 
oldfart
Elite Veteran
Location: Vancouver, Canada

Mixing Ratios

Jimmy,

Alexander has saved me a lot of typing. Follow his lead here.

Thanks Stephen - have you had a chance to try your seesaw ball variation yet?

Phil
08-08-2002 Over year old.
 
 
oldfart
Elite Veteran
Location: Vancouver, Canada

How much pitch?

Jim et al,

Here is a "rule of thumb" procedure I use on any helicopter to set my Maximum Collective Pitch.

Because different blades load differently and power systems vary, I do not like just giving a "pitch" number. Also because one can pull more top end pitch at 1500 RPM then at 2000 rpm, the rotor speed desired is a large part of this equation.

Once you choose a rotor speed at which you want to operate (say 1800), you must then set your pitch and power systems to best advantage. One must first be sure he is getting maximum from his power system (engine, exhaust, fuel, glowplug) at that rpm without being too lean. So I will start from a "safe" pitch setting - e.g. with a 46/50 and 600mm blades I would use 9 degrees. Then I would set for a RICH top end (on the OS 46 & 50 that would be about 1 3/4 open on the main needle). Then I would climb out (straight up) for at least 100 feet to be sure the crankcase has had time to clear itself of any raw fuel. I would continue this, setting the engine leaner each time until it started to sag. (stop the climb when you hear it start to drop in rpm). Then back off on the needle 3 clicks or so. Now start adding pitch until the rpm drops again. Then back off on the pitch setting a bit to that where no drop occurs (You may like to drop the collective number a bit so that it will actually speed up a tad here. This leaves you with some cyclic reserve at full collective). You can now measure the pitch if you want to know the exact number.

Depending on the altitude and temps you fly at, your top end pitch will also vary from that of another. Here at sea level, with the 600mm Hurricane blades supplied with the Falcon SEV2, a broken in OS50, the Century CN3033A muffler, CP30 fuel and Enya #3 plug, I find that even 12 degrees can be pulled at 1800, with throttle to spare. So I drop my collective to 11 degrees, reset the point at the top of my throttle curve (a bit over 80%) and leave the "spare" for cyclic mixing.

Now your engine is set for max power and your top end pitch set to absorb it. So now you can set for a smooth hover.

Now hover the heli and set the IDLE needle AND throttle opening (throttle curve setting) for a "Fat & Happy" setting in the hover. With some engine/carbs/muffler combinations, if you set the top for a very high rotor speed, and hover at the same speed, you may find it too rich at idle. Here at start up it will want to overload and die, so that one may have to pinch the fuel line intermitantly to keep it running before lift off and/or leave the glow plug attached until one has had a chance to clear the engine before lift off.
08-08-2002 Over year old.
 
 
the Wasp
rrProfessor
Location: Vt

Phil,,, buddy, ol pal,,,

,,,, could I talk you into coming down here to Vermont and set up my Falcon,,, LOL,,, it wouldn't take to long,,, LOL !!

I ordered an OS 50,,,
well,,, anyway,,, my new (14 day old) OS 46 has just a little over 1/2 gallon of fuel run through it, and we just couldn't get it to produce the power it should,,, I noticed that the muffler was lose, so I thought I would remove the muffler and look at the piston through the port, well the piston is SCORED, I think my instructor leaned it to much,,, so I ordered an OS 50, it will be here Friday,,,

I was going to wait to get the 50 in the spring and use my 46 in a scale heli, OOohh well. My 46 is going in for warranty work !!

Jim
God I wish I had more money !!
08-08-2002 Over year old.
 
 
oldfart
Elite Veteran
Location: Vancouver, Canada

paddles

As the Falcon uses a 4mm Flybar, many 60 size paddles work very well on it. I would suggest the Vario Skyfox units (they have a large area with a high aspect ratio) so they quicken the response and provide a pretty good hover. The new Black X-Cell units work similarily. For more rapid cyclic, try the new White X-cell units... large area and very light resulting in a lot of flybar power at the expense of flybar stability.
08-08-2002 Over year old.
 
 
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GrandRC . CanoMod . Futaba-RC

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Century Hawk - Falcon - Raven - Predator > what pitch do you run ??
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