Trim all the way up for best glide

MAKG1 said:
It's not really the same as an SP. Just the 180 HP engine is. Which doesn't matter if it's failed. For some reason, the ASI calibration is different for SPs at low speed (they read slower than older 172s, at the same CAS), so P's don't compare in IAS.

Max weight is also different, despite the same size engine and same flaps. P's are 2400 lb. SP's are 2550. N's are 2300 lb (but have 40 deg flaps).

With two up front and nothing else with full fuel, I'd be around 2000 lb in an N or P. Of course that will vary for the OP and for installed equipment. But that means a 20% reduction in gross weight, so V speed reduction is around 10%. That makes 63 KIAS fast.
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Actually, this is a CAP 172P STCed with Lyco O-360 and Aspen. Brings gross to 2550 from 2400. Same as SP model. While i'm sure it is not quite identical, it's a lot closer to SP than original P including change in best glide to 68(IIRC)
 
MauleSkinner said:
Ok...at what point did I say trim flies the aircraft?

roughly 80% max weight, so adjusted best glide would be roughly 90% of the published number.
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Well, then it was right on the money. +/-2. Even better :)
 
MAKG1 said:
wouldn't you expect a difference between N and P models then, too?
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They are slightly different.

MAKG1 said:
It affects the stall speeds as well (in IAS), which are always at the same angle of attack when clean (as these models have the same wing).
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IAS doesn't measure AOA. Apparently the increased position error doesn't offset the increase in speed.
 
genna said:
I was alone in the plane with 35G fuel. about 500lb under 2550 gross. Not sure on the second part
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roughly 80% max weight, so adjusted best glide would be roughly 90% of the published number.
 
Its good to know how much altitude your airplane loses in a 360 degree turn and what banking to use.
 
coloradobluesky said:
Its good to know how much altitude your airplane loses in a 360 degree turn and what banking to use.
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That would depend on how fast you do your 360.

For standard rate, it should be quite close to 1000 ft in a 172. But you have to PRACTICE it, rather than just know it. And if there is any wind, your 360 isn't going to end where it started.

It's definitely a tool in the toolbox, but I prefer to do circuits around a field if I need to lose altitude, rather than a 360. It's also an option to slip (and a better one if you're in a hurry to get down).
 
jsstevens said:
Isn't best glide at the lowest point on the L/D curve? Or is that max endurance? Dang! Math is hard.
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If the curves are right, you definitely want to go for max endurance. ;)

Or something like that. So I hear. I'm an old married fart.
 
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