Keith:
Maidened the Yak (QQ, 73", 12 lbs all up weight) today with the CDImotor. The engine would not draw fuel into the injector pipe either via the "180 degree"method described below (it did work on the test bench tough), or via open cranking.Abuddy of mine found a simpler method:Just use a Syringe to push air through the open Fuel tank pipe:this quickly drives fuel through the fuel feed, through to the needle and up the injector pipe!
Here's the debrief on the maiden.
Setup
uralite Electronic switch (2 regulators, 5.9V), dual LIPOs (1500 MAH), 15% Nitro, 8% oil. (I'm a sport flyer currently, with an interest in pattern); The batteries were plugged into the receiver (JR 921, 2.4Ghz) and a switch from the receiver powered the ignition. 18.1x10 prop.
After five flights, all lasting 12 to 14 mins, the batteries read:7.6v and 7.3v respectively. The draw seemed to be more from one of the batteries that had "high current"wiring installed on it (though the servos - six 8411's, are not high-current servos). The Asymetric readings seemed a little odd since both batteries were fully charged before the first flight.
Some strange behaviour was observed in starting the second flight:The engine would not start and seemed too rich. Ihad to turn out the pump (counter clockwise)by about 1/4 turn and then it started up properly. On the third flight, another quarter turn out was required.Thereafter, the engine started up well for flights 4 and 5.
Overall result:very satisfying. With the Hatori muffler, however, there is no noise at all so it seems a little wierd. Afriend of mine who has a full-scale Edge 540 says that the big planes just use headers, with no muffler. Is there any problem (other than noise, which is not a problem here in India :-), in running the 170 CDIwithout a muffler?That would make it could much more like a full-scale plane (though the noise would be a bit much Iwould imagine.
This is one great engine for sport flying. Reliable and powerful.Pulls the 12 lb Yak into an unlimited vertical as far as the eye can see. All on 15%. Iguess you pattern guys REALLYuse a lot of power :-).
BTW- any idea where I can get a guide to basic Pattern flying? The sequences, etc.?Do let me know if you have any pointers.
Atul
ORIGINAL: UKpatternflyer
Hi Atul, First run of the day open the throttle and crank the engine 180 degrees backwards and forwards to actuate the pump so that fuel is drawn to the injector pipe; you can see the fuel progressing through it. If after a while it hasn't reached there, there may be some congealed fuel slowing things down a bit in the system (especially on cold days), or if you've got a long tank feed, it might just take a while to get there. Either way pull the fuel feed from the tank to the pump, and ensure fuel can dribble out of it. That way you know you've got fuel to the pump ok. Reattach the pipe and repeat the cranking thing with the throttle wide open. Needless to say, only do this if you are certain the ignition unit is off with the CDi. If you still can't see fuel moving to the injector then you've either got a blockage or the needle is shut. Once fuel reaches the injector, crank the engine by hand a couple of turns to let the fuel lubricate the engine. After that you are good to go with either CDi or DZ. Don't forget to shut the throttle down to idle before starting; Boy when you forget this once, you'll never forget again. This is ok for the first run of the day; after that you shouldn't need to do it. JFYI, today: Angels Shadow DZ / 18 x 11WPN 7700- 7900 rpm; 30/20 Optifuel; Proline CDi 18.1 x 11 7800rpm; 25/10 Optifuel Hope this helps Keith