Aviatix
Topic Author
Posts: 1
Joined: Thu Oct 12, 2006 1:34 am

C172: Flaps Down Fully

Mon Oct 23, 2006 2:06 pm

Certain Cessna 172's flap operating range is between 0-40 degrees electrically driven, while another which I flew a few year's ago, was 0-30 degrees manualy operated. Why the difference? Safety?
 
Cadet57
Posts: 7174
Joined: Mon Jul 25, 2005 2:02 am

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:17 pm

Quoting Aviatix (Thread starter):

It depends on the model. The newer 172's will have the 40 degree electric while the older models the 30 degree manual


Also, welcome to a.net. Strap in and have fun.
Doors open, right hand side, next stop is Springfield.
 
Fly2HMO
Posts: 7207
Joined: Sat Jan 24, 2004 12:14 pm

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:32 pm

Quoting Cadet57 (Reply 1):
The newer 172's will have the 40 degree electric while the older models the 30 degree manual

Uhm, nope. Late model 172 SP or R models have up to 30 deg, and they are electrically driven by a motor on the left wing. IIRC, the Q and N models had the 40 deg setting.
 
Vref5
Posts: 187
Joined: Tue Dec 13, 2005 2:55 pm

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:44 pm

Quoting Aviatix (Thread starter):
Certain Cessna 172's flap operating range is between 0-40 degrees electrically driven, while another which I flew a few year's ago, was 0-30 degrees manualy operated. Why the difference? Safety?

A bit of extra climbout performance. Also makes it less likely a student will crash and burn when attempting to do a panicky go-around with 40 degrees of flaps still selected.
 
flyf15
Posts: 6633
Joined: Tue May 18, 1999 11:10 am

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:51 pm

I'd say my favorite 172 is the 210hp R172K. Variable pitched prop and 50 degree flaps. If you needed to, you could make that thing fall out of the sky like a sack of lead bricks.
 
SB
Posts: 152
Joined: Sun Aug 06, 2006 2:29 pm

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:55 pm

The maximum flap setting on the A-N models is 40°
From P onwards they stop at 30°

I think they went with electric flaps from D onwards. That was in 1962.

Cessna produced the C172, 172A, 172B, 172C, 172D, 172E, 172F (USAF T-41A), 172G, 172H (USAF T-41A), 172I, 172K, 172L, 172M, 172N, 172P, 172R and 172S/SP. Quite a family!

S.
"Confirm leave the hold and maintain 320kts?!"
 
Charliejag1
Posts: 226
Joined: Sun Aug 20, 2006 4:48 am

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 2:57 pm

Even though he does go to Embry Riddle instead of Purdue, FLY2HMO is absolutely right. Before switching to Pipers for Commercial, instrument, multi, etc, I did my private in 172s, mostly P, R, and S models. I have never seen anything other than a 30 degree electrically driven flap system. The aforementioned 40 degree manual system reminds me of a Piper Warrior 3.

FYI, my school pride is all in good fun.
 
BigJimFX
Posts: 301
Joined: Tue Jun 28, 2005 2:25 am

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 3:03 pm

Quoting Vref5 (Reply 3):
A bit of extra climbout performance. Also makes it less likely a student will crash and burn when attempting to do a panicky go-around with 40 degrees of flaps still selected.

Ummmm. The last time I checked C172 (R) POH... More flaps don't equal climbout performance. Flaps at 10 degrees are used for short field/ soft field takeoff. Not to mention that a panicky go-around would raise all flaps instead of the checklist recommended "Full throttle, flaps 20, Climb speed, positive rate, flaps 10, positive rate, Vy or Vx Flaps up.

Never flown a C172 with 40 degrees of flaps, but seeing as that I have put the flaps up from 30-0 on a go-around... (Almost 300 ft AGL and first go-around with a CFI... I lost about 110 ft) I would assume that from 40-0 on a go-around would make life a little more difficult.
I'd like to thank me for flying Me Airways...
 
Vref5
Posts: 187
Joined: Tue Dec 13, 2005 2:55 pm

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 3:08 pm

Quoting BigJimFX (Reply 7):
Ummmm. The last time I checked C172 (R) POH... More flaps don't equal climbout performance.

Reducing them does, and they also upgraded the engine at the same time they made that change.  Smile

A secondary concern was legal liability and expensive lawsuits from what I understand, though I am not sure how much that factored into their final decision.
 
Vref5
Posts: 187
Joined: Tue Dec 13, 2005 2:55 pm

RE: C172: Flaps Down Fully

Mon Oct 23, 2006 3:27 pm

Quoting BigJimFX (Reply 7):
Not to mention that a panicky go-around would raise all flaps instead of the checklist recommended "Full throttle, flaps 20, Climb speed, positive rate, flaps 10, positive rate, Vy or Vx Flaps up.

Some will, but have you ever seen an extremely flipped out student? They might freeze at a very critical moment; one where you have a very high rate of descent and not really enough time or altitude to properly arrest it without skipping a few heartbeats and a few very quick prayers.

With 40 degrees of flaps, you have a very high rate of descent. Sometimes people changes their mind when they're so close to the ground that they suddenly want to start climbing, no matter what... and if you just blindly move that lever back to zero, you will lose some extra altitude until the plane stabilizes in its new configuration.

That might not be altitude you may have available to spare. It is also a lot harder to climb out of a balked or aborted landing while 40 degrees of flaps is still selected.

It's hard enough with 30, but more realistic then, as you yourself noted and I can personally attest to.

Cessna also made this change concurrently with an engine upgrade for a little extra horsepower. So, between limiting to 30 degrees of flaps and some extra engine power, you basically have a performance boost.

Along with lessened risk of a student crashing. Most students or certificated pilots will not crash, but there's always situations or days where everything just goes wrong. Cessna, I believe, also wanted to limit their exposure to legal liability.

Cessna actually halted production of their GA planes for years until the 17 year liability rule was passed into law, for this reason. (Expensive lawsuits.)

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