Idling at 700 rpm next to impossible

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rwmarth
Senior Airman
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Joined: 07 Oct 2009, 10:25

Idling at 700 rpm next to impossible

Post by rwmarth »

I am having a very hard time idling at the manual's suggested rpm of 700 after starting the engine. The rpm when the throttle is fully closed is around 500 as per the manual, a slight increase can often get it to 600, but after that even a very slight adjustment results in the rpm jumping to 900 or above. Is this a case of engine wear (though I wasn't able to get 700 with a new engine either)? I am using the saitek quadrant and all appears to be running normal from its end: calibration is ok, and the animated throttle inside the Cub matches the adjustments made on the quadrant. Any ideas?

Also, what engine speed will the Cub begin to roll? I could have sworn I had it to 1000rpm and the Cub would sit there, but now 900 rpm is causing her to roll, and anything more she likes to lurch forward.

Thanks in advance!

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CodyValkyrie
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Re: Idling at 700 rpm next to impossible

Post by CodyValkyrie »

Couple of things... First, if you cannot get exactly 700, get as close you can and you will be fine. Idling slightly higher won't hurt anything. Even 900 RPM is not bad. Second, when idling, and really any time on the ground and especially so when more power is applied, KEEP THE STICK FULL BACK! The airflow from the propeller can make the tail of the plane begin to "fly." This is why you can apply brakes, apply half throttle and teeter on the wheels with the tail off the ground using only elevator. The tail has enough lift to get it off the ground from the wind developed from the prop. By keeping the stick in your chest, you alleviate any issue with this. In all tail draggers, unless specified, it is advised to keep the stick back while on the ground.

Your plane will move on the ground dependent on power and weight. Naturally the more weight in the plane, the less the plane will want to move. This however may change the center of gravity, which is all the more reason you want to keep the stick full back. A lot about the Cub is about "feel." Don't get so stuck on numbers. There are few gauges in this aircraft, so spend that time getting a "feel" and keeping your eyes outside your plane.

Remember in the real world numbers are not exact. Gauges fluctuate, temperatures and things as simple as spark plugs make enough minor differences that not everything is "perfect." It is only when we simulate perfection that the misconception comes into play, which is what most simulations do.
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rwmarth
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Posts: 109
Joined: 07 Oct 2009, 10:25

Re: Idling at 700 rpm next to impossible

Post by rwmarth »

Thanks for the advice Cody!

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CodyValkyrie
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Re: Idling at 700 rpm next to impossible

Post by CodyValkyrie »

No worries mate. Just glad I could help. Eventually over time you will find that the engine of your aircraft performs a certain way... You will get a feel for how she flies, and you will begin to know how she handles as she wears and things sound a bit different. Every time you complete an overhaul on the plane, you will get a completely new engine with it's own set of characteristics. This is what Accu-Sim is about.

It's interesting how Accu-Sim planes are developed... they make a perfect by the numbers simulation, and then "remove" the perfection.
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Tigerclaw
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Re: Idling at 700 rpm next to impossible

Post by Tigerclaw »

The Cub has gauges? I can't say I've noticed that to be honest. What does Heidi say? "Keep your eyes, on the sky." Well that's what she keeps saying to me anyway :lol:
Tony (That's all your getting, like it or lump it)

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