172sp cruise with no wheel fairings

dell30rb

dell30rb

Final Approach
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Anyone have experience flying a 172sp without wheel fairings? Wondering what the cruise speed is. After flying to ohio yesterday in a warrior that would only do 105 kts i'm thinking it might be worth the extra time and money to switch
 
You can count on somewhere between 115 and 110 depending on how clean it is, how well rigged it is, etc. Plus, you have windows to open when it gets too hot!
 
In most fixed-gear light singles in that class, wheel pants on all three makes a difference of 7-10 knots, and 20 extra HP also makes about 10 knots difference. So, all else being equal, a 180HP 172SP with wheel pants will probably be at least 15 knots faster than a 160 HP Warrior without wheel pants at the same % power setting.
 
Ron, you're saying that the new SP they just got at the airport I go to, should go 10+10 kts faster than the P model sitting on the line, which is 128kts?

One of the guys I talked to was hesitant and said that it's a little faster but denied that it even did the 120kts I'd read about.
 
Jaybird180 said:
Ron, you're saying that the new SP they just got at the airport I go to, should go 10+10 kts faster than the P model sitting on the line, which is 128kts?

One of the guys I talked to was hesitant and said that it's a little faster but denied that it even did the 120kts I'd read about.
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I'd expect a new 172SP with wheel pants to do 120 KTAS or a bit more at 75% power. I'd expect a 172P without pants to do about 105 knots at the same power setting. So yes, somewhere around 15 knots difference. If you aren't getting 120 KTAS out of a new 172SP with wheel pants, either you aren't pulling a full 75% power, or there's something draggy (or unthrusty) going on.

One point to be mentioned -- the combination of drag reduction and extra power isn't additive. The curves go up exponentially, so as speed goes up, you're getting less return on power and less return on drag reduction. Hence, 7-10 plus 10 equals more like 15 than 20.
 
We lost about 8 knots when we took the pants off our 172SP..
Dan
 
The 172N I fly (180 hp) is good for about 114 KTAS at 65% (2400 rpm) power. Pants on nose and mains.
 
dell30rb said:
Anyone have experience flying a 172sp without wheel fairings? Wondering what the cruise speed is. After flying to ohio yesterday in a warrior that would only do 105 kts i'm thinking it might be worth the extra time and money to switch
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Do you own, or rent?

I would expect to see maybe 115 knots in a 172SP without pants, assuming it's properly rigged and such. However, you might want to look even higher - If there's a 182, Arrow, Dakota, etc. for rent at your flight school, that might turn out to be cheaper. When you divide things out, IME the 130-135 knot birds such as I've mentioned above are often the cheapest per MILE despite being more expensive per HOUR. When I'm going somewhere, I'm happy if I can spend around $1/nm. Forget the hourly costs on trips, it's the mileage cost that counts, unless you're specifically looking to build plain-jane flight time for some reason.
 
I rent. I can rent a no pants warrior 2 for $100 or a no pants 172sp for $122 an hour. Shame they take the pants off of these aircraft. Had problems with pilots tearing them up. I guess. But i really would have appreciated the extra few knots yesterday.

The warrior i flew was supposedly the slower one but i think we were seeing about 100, maybe 105 kts out of the airplane. Long flight from raleigh to northern ohio fighting a 15kt headwind. Should have saved the money and taken a 95kt 152 for $70 an hr.
 
dell30rb said:
Had problems with pilots tearing them up. I guess.
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Depending on where you are. A lot of flight schools remove wheel pants for lots of reasons.
- easier to find where renter pilots have flat spotted tires from landing with the brakes on.
- easier to observe low pressure tires on preflight
- easier to find the fill valve to air up those low tires
- quicker turn times to change that flat tire from the last renter when you don't take 30min to remove a pant, and 30min to put it back on.
- no fiberglass repairs from the tire collapsing when the pilot blew it out landing with the brakes locked
- easier to inspect brake pad wear from pilots dragging the brakes while taxing, KEEP YOUR HEELS ON THE FLOOR!
- easier to see the valve stem on preflight, if it's straight, the tire has not slipped on the rim, if it's tipped, the tire has slipped and the next landing on a low pressure tire could cut the valve stem
- in winter climates, snow, slush and ice does not build up inside the pant and freeze the tire in position, it's like landing with locked brakes.
 
BillTIZ said:
Depending on where you are. A lot of flight schools remove wheel pants for lots of reasons.
- easier to find where renter pilots have flat spotted tires from landing with the brakes on.
- easier to observe low pressure tires on preflight
- easier to find the fill valve to air up those low tires
- quicker turn times to change that flat tire from the last renter when you don't take 30min to remove a pant, and 30min to put it back on.
- no fiberglass repairs from the tire collapsing when the pilot blew it out landing with the brakes locked
- easier to inspect brake pad wear from pilots dragging the brakes while taxing, KEEP YOUR HEELS ON THE FLOOR!
- easier to see the valve stem on preflight, if it's straight, the tire has not slipped on the rim, if it's tipped, the tire has slipped and the next landing on a low pressure tire could cut the valve stem
- in winter climates, snow, slush and ice does not build up inside the pant and freeze the tire in position, it's like landing with locked brakes.
Click to expand...
And easier to allow those not accustomed to landing on turf to do so without undue (some would say unfounded) fear of damaging the fairings.
 
I owned a 1998 172 with the 180 upgrade. With the pants I got 118-120kts. Without the pants I would get around 110kts.
 
Ron Levy said:
I'd expect a new 172SP with wheel pants to do 120 KTAS or a bit more at 75% power. I'd expect a 172P without pants to do about 105 knots at the same power setting. So yes, somewhere around 15 knots difference. If you aren't getting 120 KTAS out of a new 172SP with wheel pants, either you aren't pulling a full 75% power, or there's something draggy (or unthrusty) going on.

One point to be mentioned -- the combination of drag reduction and extra power isn't additive. The curves go up exponentially, so as speed goes up, you're getting less return on power and less return on drag reduction. Hence, 7-10 plus 10 equals more like 15 than 20.
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Yeah, with higher speeds drag can be a real parasite sometimes :)
 
Dan Thomas said:
We lost about 8 knots when we took the pants off our 172SP..
Dan
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Let the childishness in me be known.. but am I really the only one who chuckled at this? :D

FWIW, the flight school I used for rental has two panted and one unpanted 172SP's, noticed no more than 5-7kts, maybe it's the Florida heat? *shrug*
 
VTC_WS6 said:
Let the childishness in me be known.. but am I really the only one who chuckled at this? :D
Click to expand...

No. I could have worded it better but left it as it was. And then there's "debriefing..."

Dan
 
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