First Raptor 90

[dacostad]

I am just completing my fist 90 size heli, a Raptor 90SE.

What is the bottom connection on the fuel tank for? I assume it remains unused and is therefore blocked off. If so what is the preferred way of blocking it off?

Thanks


David

[invertmast]

my 60 has a piece of tubing and a aluminum stopper plug pushed into the end of the fuel tubing and zipties to keep it from coming off...

or you could do it the ghetto fab. way and just stick a bolt in the fuel tubing and zip tie it to keep it from coming off.

[creightoncarr]

Yes, just use a short piece of tubing and the aluminum stopper from the kit. I do sometimes use the bottom nipple to completely drain my tank at the end of a day.

[dacostad]

Thanks guys.

David

[dacostad]

So now I am ready to test fire my Raptor 90SE up and need some help with the engine settings.

I am using a OS Max 91SZ-Hring PS-Hyper pumped engine and a Hatori SB-17H muffler and also pressurizing the fuel tank from the muffler.

I have set the initial carb settings as per the manual, ie the high speed is set to 2 1/2 turns from closed, idle mixture left at factory which is between 10 past and 1/4 past the hour, with the medium speed valve set at 1.5 turns from fully closed.

The engine starts with no problem and idles quite well, however as I open the throttle beyond idle to about 50 - 60% the engine really starts to cough and splutter and struggle.

I have pinched the fuel line and the engine revs increase significantly for a while before fuel starvation sets in so I guess I am running rich, but I am not sure what to adjust as I don't have much experience with nitro engines.

Any help is appreciated.

Thanks


David

[Neriyah]

Keep closing your middle needle 1/4-1/8 turn at a time till it runs well. You'll most likely end up around 1/4 turn open from fully closed. Some close it all together but since this is a new engine I think you'll prefer to leave it a bit on the rich side...

[iher]

Hi!
According to some people ( not me yet, until I get mine and study the subject thoroughly ) you don´t need to pressurize the tank if you use the pump. This apparently helps keeping a more continuous fuel feed into the carb.

what altitude and % nitro are you using?

Remember the break in process( that is a whole subject), don´t skip it or you might end up with a difficult or a short life motor.

Let us know how it went.
ian

[toro]

yea.. dont pressurize off of muffler, and run a fuel magnet.

[werew]

I'm helping a friend tune his and it clearly states set your idle first using only your idle screw and high speed screw. Don't mess with medium needle til high and low is set. Ignore the mid-throttle behavior and adjust for high throttle first!

I prefer using a flat line pitch curve @ 47% so there's just a little bit neg pitch. This way you can rev your engine thru the entire engine rpm range without worrying about your heli being mid air and ur engine bogging out on ya.

Your idle screw dictates how much O2 can be "inhaled" thru out the throttles entire rpm range, i'd leave it at factory setting for break in (1-2 tanks) and goto your high needle and lean it until your engine stays running at idle w/o plug warmer on. If exhaust smokes @ high and no bog @ high, leave it. Sometimes the idle needs to be adjusted too...

Next observe in between idle and high, if it sputters and smokes heavily in mid throttle, lean it. Test entire rpm range again and keep adjusting til all rpm ranges are smooth in transition and it's smoking good.

Once you're confident your engine will not bog out on you, throw in a pitch curve of 47-47-50-75-100. That'll get you up in the air. Also... your throttle curve, don't overspeed your head... In throttle curve set a max throttle % of 80 to begin with.

Once you're in the air it might act a lil different when loading the head with collective pitch. Adjust accordingly

I agree on not using muffler to pressurize fuel tank, take the tubing nipple off the muffler and plug the hole.

Hope this helps

[iher]

WOOOOOHOOOOO!!!
I just got the news that a brown suited guy with a big brown van left a big brown cardboard box at home
this only means one thing: my Rap 90 SE is home!!!!! :) :)