Gasser Throttle Curves (Baseline)

[rccardude04]

I'm sure I've read before what the baseline curves should be, but I dug through several pages checking pretty much every post on "setup" and didn't see anything about baseline curves.
I know it's going to be different than my nitro .50 but I'm not sure how much different. It seems like the butterfly would make it seem like it has a bunch of positive throttle expo (for you JR guys, it's negative ;)).
I was thinking about setting it to something like 0-10-25-50-100 Sound close?
I'm running the stock muffler, with the Z-RC insulator, and some MS Composit 800 blades, with Raja's beautifully crafted generator. Stock tail blades and paddles.
I'll be setting up 2 of these actually. Mine on a 9CAP, and one on a 14MZ (should be interesting on the 14. That's a shiny radio :))
Thanks for any/all input. :)
You'd think I woulda flown this thing by now... Turns out, the guy I contracted to paint my canopy has been lying to everybody. He basically stole my fiberglass canopy and the Lexan was donated to someone else a long time ago. I'm finally getting my UNPAINTED canopy back after several months of waiting. I'm going to have another, more trustworthy friend paint it up for me all nice and shiny so I can balance this sucker out and give her a test flight.
I'm so excited! :D
-Eric

[v22chap]

I like to get the motor up to speed and the clutch engaged early ,,so I would probably go 0-15-30- 50- 100 .. but your curve is close ,, go fly it ,,,you don't need no stinkin canopy to fly these and have fun . :wink: :D

[cbergen]

If you have it setup mechanically with the ATV's at or near the same for high and off throttle, then you should end up at around 40-45% at mid throttle in a hover.

Should look something like this, 0,25,45,75,100. Then tweak the 1/4 and 3/4 points to keep your RPM's constant while climbing and descending.

This is a normal curve for a 1450 headspeed. For idle up curves, increase accordingly for a 1550 and a 1650 headspeed.

[rccardude04]

I've got my 0 pitch somewhere around -5 in normal mode with +10 at top stick, and zero pitch at the middle.
I'm also always very, very anal about making sure everything is symmetrical so my ATVs are identical in both directions. :)
I don't think I'll have any trouble getting it set for constant rpm, but I don't have a tach so I want to try and get it close. I got my raptor within 100rpm of where I wanted it so hopefully this one won't be too bad :)
-Eric

[rbort]

Do you have a governor? If so use that to dial in the throttle curves, works just as well as a tach and you can do it yourself without a buddy to use the tach for you.

-=>Raja.

[rccardude04]

I don't have a governor yet. I try to set stuff up without one so I'm not tempted to cheat it :)
Planning on a gv-1/gator though. From what I've read, it should be a good combo, no?
-Eric

[lperagallo]

Eric,

The GV-1 and Stator Gator is a great combo. I run one on my Bergen. A word of caution....Make sure your engine is broken in and your curves are set up correctly before running a governor. Chris warned me about this and it took a while to get the GV-1 to work right, but now it's sweet.

Lou

[rccardude04]

How long to break in the engine? Couple gallons?
I always make sure I have my curves set where I want them before putting on the governor. On my raptor, I'm not sure if I could tell if the governor failed. It just makes it so the thing won't unload on me during high alpha descents :)
These engines come set to run pretty well from the factory don't they? Meaning I shouldn't have to mess with the needles should I?
-Eric

[lperagallo]

You need to set up the engine to match your pitch curve. Start at 1 3/8 on both high and low needles, then see how it runs. Gassers are different then nitro and you can't really set them up the same way. You need to get the engine in the power band just before you load the disk. The Bergen hovers on the low needle and transitions to the high needle when you need power. Work the low needle first, then the high. Make very small adjustments, the width of a screwdriver. It took me a trip to see the Bergens to see how to set up the engine, pitch curve and throttle curve. Once you get it right, it is smooth and powerful. You also can't beat the fuel economy and long flights. I run about 15 minutes on a half a tank of fuel. I have a two gallon can and I haven't had to buy fuel in a long time and I fly any day the weather is reasonable. It took about two to three gallons before the engine seemed to be broken in well. I use Penzoil full synthetic outboard oil so it may have taken a bit longer to break in.

[cbergen]

These engines come set to run pretty well from the factory don't they? Meaning I shouldn't have to mess with the needles should I?


To coin a phrase, There are NO factory settings on these carburetors!!

On brand new engines I have found everything from fully closed to 4 turns out.

YOU must set the needles to 1 3/8 turns out on both needles as a start.

[rccardude04]

Alright, I'll do 1 3/8 :)
Good thing I asked.
Do the gassers tune similar to nitro engines? I've done nitro on cars, planes, and helicopters (and even a little bit with boats), but never a gas engine.
Do you listen for the similar gurgle/pingy noises?
-Eric