Hi all,
I have also heard of Bill Lockwood's opinion that the gear box can suffer damage
if the idle is set below 1800 rpm. I have a few thoughts on that subject.
1. Even at 1400 rpm idle setting, the Rotax/Europa recommended idle speed, the
plane tends to float a little on landing (we have a short wing XS with 912S and
Whirlwind CS prop). At 1800 rpm idle setting (we tried this ONCE, after speaking
to Bill L.) the airplane becomes difficult to get down, a potential safety
concern, IMHO. We are currently set to a compromise of about 1600 rpm. The
engine
idles fairly well and the plane eventually returns to earth at idle (except on
those pesky runways with some down slope).
2. Does a gear box that can be damaged this easily belong on any airplane?!
3. I have a Honda 919 motorcycle (four cylinders, 919 cc, 115 hp at the crank)
with virtually no flywheel and a very light crankshaft. It idles quite well at
1200 rpm, immediately on start-up! Why is it that a longer stroke Rotax, with a
flywheel, cannot be made to idle smoothly below 1400 rpm (or 1800 rpm, according
to Bill L.)? Is this 'rocket science' too much to expect in a 'modern' aircraft
engine? I suspect an ignition system with centrifugal advance (or electronic
equiv) and electronic fuel injection might help.
We have 250 hours on our engine now. Less vibration and noise at cruise would be
greatly appreciated, so we will be trying the softer mounts soon. If the Rotax
engine/gearbox craps out because of this, maybe we need to start looking at an
engine swap with my bike.
BTW, we have had our prop dynamically balanced three times, and have adjusted
our
carbs with a solid state differential pressure transducer in place of the
balance
tube. We adjusted with the cables at high throttle settings and with the idle
stops at idle.
regards,
Terry Seaver
Ron Parigoris wrote:
>
> Hey DJA727
>
> On my speedwing monowheel, i plan on installing a 914, with CS.
>
> I spoke to Bill Lockwood, from Lockwood Aviation in FL for some time
> bout the rotax motors.
>
> Any viabbarion kills the redrive. Unbalanced carbs, idle too slow and
> "MOTORMOUNTS THAT ARE TOO SOFT!"
>
> I am not an expert. I never saw a 914 mount in my hand.
>
> But Bill is suppsedlly an expert and says that 0200 mounts are a bad
> thing.
>
> He said use the provided mounts, idle 1800RPM min, sync carbs exact both
> low speed and high and have prop dynamic balanced.
>
> Here is his exact quote:
>
> "Motors like to be mounted fairly rigid, he is not real thrilled with
> continental 0-200 Lord mounts if they are softer"
>
> This is per a conversation 12-30-2002.
>
> I am only repeating what he said.
>
> Any other comments to the contrary?
>
> Ron Parigoris
>
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