Shaun3000 From United States of America, joined Mar 2002, 445 posts, RR: 0 Posted (11 years 7 months 6 days 18 hours ago) and read 23852 times:
I don't know why I just thought of this, but here it goes. I took my private checkride, over a year ago, in a 172. The check pilot asked me what kind of flaps the 172 had. I told him Fowler, since they slid back on a track when set to one notch, and then lowered when more flaps were commanded.
He said I was wrong and they were slotted. We had a good discussion about it, and I said they shoudl be Fowlers since they slid back more than down on the first setting and increased wing area. But the POH said slotted, so that's what he wanted. (It didn't affect me, though, I sill passed. haha)
SO, what kind of flaps does a Cessna 172 have? Slotted or Fowler?
Aaron atp From United States of America, joined Mar 2000, 533 posts, RR: 2
Reply 1, posted (11 years 7 months 6 days 16 hours ago) and read 23824 times:
If you are going to call them fowler flaps, you would need to call them "single slotted fowler flaps"
I think that given the 175 ft2 surface area, the extra <7.5 square feet from the flap travel isn't that noticeable. Therefore, calling them slotted is probably more correct. I think the official word from Cessna is indeed 'slotted.'
7.5 ft2 equates to a 4.2% increase in surface area for an aircraft at 2300 lbs is not completely neglibable (<100 lbs by rough mental math [L= Cl q S], but probably <50 lbs considering the TE design of the wing). However, I think if I had time to do the math I could show you that it isn't nearly as important (effective) as it is for jet aircraft that are equipped with double/triple slotted fowlers. Compared to the lift increase due to change in camber, the lift due to extra sfc area is irrelevant on the C172.
Maybe someone who has worked with C172 graphs more recently could come up with actual numbers.
So I haven't actually told you anything in this post, but at least look at it as a different way of evaluating the problem.
NormalSpeed From , joined Dec 1969, posts, RR:
Reply 4, posted (11 years 7 months 6 days 13 hours ago) and read 23797 times:
Interesting. I probably would have said "fowler" too. Well, it just goes to show you should read your POH. Actually, I DID get that question on my CFI checkride. I had to teach a lesson on Airplane Flight Controls (or whatever the exact name of that Technical Subject Area was.) And I did say that Cessna flaps were fowlers. And I didn't get any challenge on it. In fact, I would have just gone on thinking that Cessna flaps were fowlers if I hadn't read this thread.
Now, the flaps on the Warrior/Archer/Arrow--THOSE are slotted flaps.