RS2K

My Feedback: (8)

What head speed should I run my helicopter at with an OS 50 SX-H with a CY muscle pipe and how far out should the pipe be from the header? I want to get it on the pipe and unfortunutly I don't know the difference between 1700 and 1900 headspeed by sound yet.

Once I have my engine set to run correctly at 1900 and I also prgram a throttle curve to run at 1500, how will my engine resond if set to run at 1900?

Thanks for any help!

Hitch-Hiker

I kind of liked the stump story... but since it is removed, guess my reply to it isnt necessary either.

RS2K

My Feedback: (8)

Since some people can't seem to get past the story, to the question, I will leave the question by itself. I guess people just freak out when they hear the words "tach" and "heli" in the same sentence.


Here are the only things I want to know:

What headspeed should I be at when using a CY muscle pipe? How far from the header should the pipe be?

Barbary

you're supposed to choose your head speed and then adjust the pipe to come on at that speed. there's no single head speed for any given pipe, that's why they're gapped differently for different engine rpms.

RS2K

My Feedback: (8)

Yes, I know but I'd like a headspeed for the recomended 1/4 inch gap. Do you know what that is?

Barbary

no, but an os 50 peaks at a higher rpm than the 91 curtis is using. if you set the pipe to come on at the combustion frequency of a 91, it's probably going to give you a lower head speed than you want, depending on your gear ratio. why don't you just light it up and experiment?

Hitch-Hiker

What I use (not in any way meaning it is the right or only way...)

OS 50 and TT 50
CY MP for the 61 engines
GV1

Pipe is about 1/4 inch off the header. (if you are over reving in a decent, and are burning plugs, you need to be a little longer) Proper glow plug and fuel is also a variable.

I run head speed at 1600 in hover Idle 1 is 1800-1850 and Idle 2 is 1900-1950. Of course blade choice will affect what head speed you will like most. I use zig saws.

the GV1 keeps a very nice head speed with heavy 3d. And you dont need a tach anymore.

Some say that the mp will act as a governor. I never really was able to see what they were talking about. At least not on the 50 sized engines.

Vance

I have my gap at 5/16''
OS50
MP
Enya #3
CP 30%
600mm FRP Airborne models blades @ $33.00
1600 in normal
1875 in IU 1&2

I mount the coupler on the pipe with about 1/2 the coupler on the pipe end. Secure it with tie wraps or pipe clamp. I then use a plastic caliper and measure the total distance from the open end of the coupler to the beginning of the pipe. Subtract 3/8'' from this measurement and put a scribe mark on the header at this measurement. Measure in 1/16'' towards the end of the headerand put another scribe mark and then measure in another 1/16'' and put another scribe mark. You now have scribe marks at 3/8, 5/16, and 1/4. Now mount the pipe with the coupler and you can use the scribe marks on the header to get an accurate measurement exactly where your pipe is and you can make accurate adjustments at the field to adjust it to 5/16 or 1/4 if you want.
My OS 50 like to be pretty rich on the low speed needle to get a nice smooth hover.
Vince D

RS2K

My Feedback: (8)

Thanks for the help! I guess I really should just get a GV-1. I have seen the effect of the CY Muscle pipe acting as a governer to some extent. When I was still having my pitch problems due to bad thrust bearings sometimes I'd get no pitch and only throttle. Before I had the CY muscle pipe it over sped like CRAZY! I thought it was going to fly apart it was going so fast. When I installed the CY pipe it had a lot more power but when I started to get no pitch again it oversped but MUCH slower.

I am running 30% CP, an OS #8, and a fuel pump. I am still tuning my engine but am getting much closer. My hover is now smoother since I moved the pipe in a little and my idle is richer. I am guessing that I am running my head around 1900. I really like running a high headspeed becaue of the way it handles. I also love the CP30! I know some people don't like the smoke but I LOVE IT!

Oh yes, I also have 600mm TT woodies on it.

Barbary

fyi, i read on cy's site that he doesn't use a governor because it tends to fight the pipe. i then put a gv-1 on my xcell with an os 50 and hatori pipe. couldn't get the engine to run right. at full throttle it wasn't really winding up, but with the gov off it would behave fine. i ended up taking it off, mixing in some throttle to cyclic, and now it has great power, stays on the pipe and head speed is consistent during 3-d. the same gov works great on another xcell i have with a muffler. if your head is overspeeding you can lower the top end of your pitch curve and use the reserve for mixing during hard cyclic pulls.