PA28-140 Performance Charts

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sfzpilot

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sfzpilot
Hi everyone,

In the process of buying a PA28-140 with the 160 HP upgrade and noticed the performance charts are somewhat lacking.

Does anyone have any good gouge about fuel flow in the climb? Trying to plan some cross countries and want to make sure I accurate account for climb fuel, and yes I'll be extra conservative.

Also what's everyone's favorite way to use the fuel? It seems like the manual says run on one for an hour and then switch and run the other tank nearly empty, and then switch back. Anyone use this method or others?

Thanks!
 
Are you trying to go max endurance? If it doesn’t have a totalizer or engine monitor than you are betting a lot on leaning technique and book numbers. The Lycoming Operators Manual should has plenty of numbers but they are spaghetti charts and take a little effort to decipher. The minimum fuel flow at 100% rated power is graphed at 13.5 GPH and then it goes down from there as the HP diminishes (increased altitude).

The only 140 I’ve flown has this 160 hp STC and I’m done with the climb in 10 minutes or less so it’s not a big concern for me, so I can’t help there. I believe the overall average fuel burn I’ve calculated is under 8.5 gph or less IIRC.

I usually burn 30 minutes each tank otherwise, with no autopilot, I start to notice the imbalance.

There is only so much precision in setting RPM with a simple tachometer, so spend some time on mid-range flights to gather data before shooting for max endurance.
 
I suggest that you use the charts for a pa-28-160 or a Warrior II.

I had a 140 with a 160hp STC and repitched the prop so that the engine/prop matched the stock Warrior II. I used the Warrior II performance charts... or when being sort of lazy, I just planned for 8.5 gph.
 
I have the LyCon 160 HP upgrade and didn’t get any additional paperwork with it. There are great charts in the Lycoming operators manual for the O-320. Fuel flow is probably a bit more than stock O-320-E which I have. But they have charts for O-320-B and D** which are 160 HP so those are probably close enough.

https://www.lycoming.com/sites/default/files/O-320 Operator Manual 60297-30.pdf
 
My Cherokee 160 running ROP used 8.8 gph all in - I just rounded it to 9 for flight planning (taxi, climb, cruise, descent, land).

I preferred to make the first tank switch at 30 minutes, and then every hour after that.
 
GRG55 said:
My Cherokee 160 running ROP used 8.8 gph all in - I just rounded it to 9 for flight planning (taxi, climb, cruise, descent, land).

I preferred to make the first tank switch at 30 minutes, and then every hour after that.
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That was my fuel tank schedule in the Arrow, as well. The tanks were never more than 30 lb out of balance that way and the heavy side alternated due to the 1-hour switches after the first switch. I also started on the left tank since I was usually solo or at least the heavier person in the plane so the left wing was already the heavy one.

As far as fuel burn in the climb, the conservative answer is to assume it’s burning the 100% power fuel flow for the engine. I always planned in my Arrow for slightly worse than real fuel burn and slightly worse than real TAS. I always landed on time with a little extra gas. Don’t overdo it, because you really do want to know what the plane can do without tankering gas unnecessarily. But never push the envelope into the territory where you land later than planned on a highway just outside the airport fence.
 
Thanks for the replies everyone! Airplane is going under inspection so we shall see how it goes. It has the 160 STC engine in it. I haven't looked through the flight manual that's in the airplane very thoroughly yet since I don't have access to the plane. I've googled some V-speeds for the PA28-140s and it's interesting to see how there are some different V-speeds out there (and yes converted to the same units of measure). The ASI in this plane is MPH. Does anyone have the V-speeds handy? Also does anyone happen to have a "procedures" handbook for maneuvers for this plane? Thanks!
 
I put 700 hrs on one in 5 yrs. 8.5 gals/hr. 2350 rpm= 110 kts.
 
BarryCooper said:
I put 700 hrs on one in 5 yrs. 8.5 gals/hr. 2350 rpm= 110 kts.
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Thanks Barry! Do you have the V-speeds for the airplane handy since I haven't gotten our plane yet. Trying to do some learning.
 
sfzpilot said:
Thanks Barry! Do you have the V-speeds for the airplane handy since I haven't gotten our plane yet. Trying to do some learning.
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Vx 75 mph
Vy 85
Vg 85
Vo 55
Vr 65
I always came over the numbers at 75mph
 
The numbers threw me - note, mph, not kts. 75 kts over the numbers would be very fast.
 
I owned a 1968 Cherokee-140 with 160 HP for 14 years and put 500 hours on it. I planned 11-12 GPH for climb and estimated fuel burn in cruise based on TAS in flight. I wrote an article in Airfacts Journal about it. https://airfactsjournal.com/2014/02/knowing-true-airspeed-fuel-management/
The POH gives you TAS at various altitudes and power settings. It is relatively easy to flip the equations to give you fuel burn vs TAS when leaned properly ROP. The article includes a TAS correction chart with fuel burns for your aircraft. IT IS FREE

Hope this helps.

IM me if you have any questions. I still have the files on my computer, but the files are no longer available from AirFacts Journal.

You also asked about how to use the fuel? I change tanks initially based on the analog clock in the dash. If the minute hand is on the left side of the airplane I am on the left tank, if it is on the right side I am on the right tank. If I feel like I am holding pressure on the aileron because there is more weight on the other side I switch tanks to change the loading and unload the aileron hold. After you have flown a few long XCs you'll be able to feel when it is time to switch.
 

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On a 140 don’t the performance tables read:

-10 IAS - some
IAS - a little bit
+10 IAS - not much
 
Well, received the airplane. The Owner's Handbook is quite thin and not as thorough as more modern airplanes. I'm pretty sure a new 172 has more performance pages than the entire Owner's Handbook as my PA-28-140.

Now that I have the plane, a couple of questions:

1) Is there a way in '72 PA28-140 to raise the seats? I found the adjustment to move the seat forward and aft but haven't found a way to lift the seat.

2) I read on a checklist I found online to avoid continuous RPM at 2000-2200 RPM in cruise. I don't see anything on this in the manual. Any ideas why or if this is valid? Since the goal is try to build time, we're not in a rush to get anywhere and fuel is the biggest expense. However, we also want to make sure we're treating the engine the way it should be treated.

Thanks for any info!
 
sfzpilot said:
Well, received the airplane. The Owner's Handbook is quite thin and not as thorough as more modern airplanes. I'm pretty sure a new 172 has more performance pages than the entire Owner's Handbook as my PA-28-140.

Now that I have the plane, a couple of questions:

1) Is there a way in '72 PA28-140 to raise the seats? I found the adjustment to move the seat forward and aft but haven't found a way to lift the seat.

2) I read on a checklist I found online to avoid continuous RPM at 2000-2200 RPM in cruise. I don't see anything on this in the manual. Any ideas why or if this is valid? Since the goal is try to build time, we're not in a rush to get anywhere and fuel is the biggest expense. However, we also want to make sure we're treating the engine the way it should be treated.

Thanks for any info!
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1 - no.

2 - do you have a stock 140? if so, then that RPM restriction does not apply to a stock 140. If you have an STC to convert the engine to 160hp, then you need to look at the STC documentation. But I suspect the restriction you are referring to applies to certain 180hp cherokees.
 
Bob Noel said:
1 - no.

2 - do you have a stock 140? if so, then that RPM restriction does not apply to a stock 140. If you have an STC to convert the engine to 160hp, then you need to look at the STC documentation. But I suspect the restriction you are referring to applies to certain 180hp cherokees.
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I guess a seat cushion it is then! I'm 5'11" and couldn't see very well! Yea, it has the STC for the 160hp. When I get back, I'll check the documentation to see if it says anything.

Thanks!
 
sfzpilot said:
I guess a seat cushion it is then! I'm 5'11" and couldn't see very well! Yea, it has the STC for the 160hp. When I get back, I'll check the documentation to see if it says anything.

Thanks!
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The plane should have a placard for any operating limitations like that. You should also read the POH, which will have a section for required placards in case your placard has fallen off the panel. The STC document itself will have more information, but any restrictions on how you fly the plane should have made it into the POH and/or placards.
 
The 140 I fly has a hand crank underneath the pilot seat to raise it.
 
TrueCourse said:
The 140 I fly has a hand crank underneath the pilot seat to raise it.
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The only hand crank mine has is the Studebaker window crank for the overhead trim. Although Piper states in it's literature that the 1970 models switched to the trim wheel down by the flap handle, my 1970 does not. I wonder if someone installed Arrow seats in your 140.
 
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