Power Flow performance testing

[pfactor]

I'm going to have a PowerFlow installed in my '77 J model when it goes in for annual later this month. I want to do some before & after testing to actually measure the benefits I see.

Power Flow claims it will do these things for a J model:

• 5 -7 knots faster cruise speeds
• 10% – 15% increase in rate of climb
• 0.5 – 1.5 gph reduction in fuel burn at equivalent airspeed
• Improved Take-Off Performance (100’ – 300’ reduction in ground roll)
• Increase in Service Ceiling of 2,000’ – 5,000’
• Cooler CHT’s

Here's what I'm planning to measure in my tests.

• Short-field ground roll and climb performance at Vx
• Normal takeoff ground roll and climb performance at Vy
• Cruise performance at 2500, 7500, and 11,500 MSL  (replicate these performance tests)
• Find service ceiling (can maintain at least 100 fpm climb)

I'm open to suggestions for other things I should test. I plan to do the "before" testing next weekend.

Phil

[carusoam]

What are you going to use to measure these?

I used an app called CloudAhoy to measure the performance of the 310hp TopProp performance.  The SkyRadar provides WAAS data for the accuracy that you need for proper T/O distance.

Check the cloud ahoy app for what it will do before you buy it.  It has become an excellent app for flight instructors. Used to debrief a flight with a student.  Full memory of what the student did.  The student really appreciates it.

I was the student when using the app...

best regards,

-a-

[philiplane]

It will do all they claim. I put one on a 67 F model about 7 years ago. The owner still has the plane and the exhaust has been one of the best upgrades he did. The only other high performance option available would be the 210 HP mod, which uses slightly higher compression pistons from the helicopter version of the IO-360.

[jetdriven]

The 201 exhaust is better than the previous versions. I don't think the reported gains are nearly as much

[Piloto]

Measure the cockpit noise level at full power also. 

José

[garytex]

I think it's great that you are going to undertake this project.

[Bob - S50]

How about time to climb.  Be sure you have the same fuel on board, pick your desired climb speed then climb without leveling off all the way to 11,500'.  Record your times at several altitudes on the way up.  Then do your cruise testing at 11,500', then 7500', then 2500'.

I wouldn't bother checking the service ceiling unless you regularly fly at altitudes needing oxygen.  You do know you will be up around the flight levels and have to be IFR if you get there right?

I thought I read someplace that you get the biggest benefit at higher altitudes so I would expect the biggest benefit at 11,500', somewhat smaller benefit at 7500', and little to no benefit at 2500'.

Here is a link to an article in which they compared performance improvement on a Mooney: Review

Let us know how it works out and if you don't mind, how much it costs.

[Bob_Belville]

I installed a PFS in 2012. I like it a lot and think it helps performance in my M20E. We've lubed the slip joints @ annual and it has required no other attention. Unfortunately, I was already down with a failed muffler/tailpipe when I bought the PFS so I did not get to quantify before and after performance. Cost was $4600 in 6/2012 plus installation which was probably an hour or two with me helping.  

[slowflyin]

I think it's great that you are going to undertake this project.

+1

[pfactor]

What are you going to use to measure these?

I used an app called CloudAhoy to measure the performance of the 310hp TopProp performance.  The SkyRadar provides WAAS data for the accuracy that you need for proper T/O distance.

 I'm planning to use video to measure the takeoff distance. I can mount a GoPro under the wing which gives a good view of when the wheels actually break ground. Counting runway stripes should give a pretty accurate distance measure. I just started using CloudAhoy, and I'll see how its calculated takeoff distance compares to what I see on the video. I upload the GPS data from my Garmin 796 to CloudAhoy, which will give me WAAS accuracy.

I'll also have a camera pointed at the instrument panel so I can review things like pitch angles and speeds after the flight.

[pfactor]

Measure the cockpit noise level at full power also. 

José

I don't have a good objective way to do this.

Phil

[pfactor]

How about time to climb.  Be sure you have the same fuel on board, pick your desired climb speed then climb without leveling off all the way to 11,500'.  Record your times at several altitudes on the way up.  Then do your cruise testing at 11,500', then 7500', then 2500'.

Good idea. I'll do that.

I wouldn't bother checking the service ceiling unless you regularly fly at altitudes needing oxygen.  You do know you will be up around the flight levels and have to be IFR if you get there right?

The last time I tried to climb high in my 201, it was a pretty hot summer day and she pretty much was done climbing at 16,500. I don't plan to see if I can actually get to the flight levels, but maybe I'll record my time to climb to 15,500

I thought I read someplace that you get the biggest benefit at higher altitudes so I would expect the biggest benefit at 11,500', somewhat smaller benefit at 7500', and little to no benefit at 2500'.

Here is a link to an article in which they compared performance improvement on a Mooney: Review

That article was great! Thanks for linking that. I didn't know that Power Flow's "travelling machine" is a 1977 201. That's exactly what I've got.

Let us know how it works out and if you don't mind, how much it costs.

I pre-ordered the exhaust so it's waiting at Top Gun for the install at annual. Preordering saved me some money. $4390 for the 201 kit with the ceramic finish.

Phil

[Bennett]

PowerFlow inside a LoPresti cowl is tight, but a great combination on a 201. Add a Top Prop (or a new MT prop), and the usual speed mods from LASAR, and you have a real hot rod.

[OR75]

how does one determine the compatibility between all the STCs ?

power flow and new cowling ?

power flow and MT or Hartzell prop ?

just wondering since I recall seeing someone here having to resell a component because of STC compatibility (I cannot recall if it was a prop or a power flow) 

[KSMooniac]

it is up to the installing IA to make a determination of compatibility.  

[Bob_Belville]

I don't have a good objective way to do this.

Phil

Look for a smart phone app.

[chrisk]

 I'm planning to use video to measure the takeoff distance. I can mount a GoPro under the wing which gives a good view of when the wheels actually break ground. Counting runway stripes should give a pretty accurate distance measure. I just started using CloudAhoy, and I'll see how its calculated takeoff distance compares to what I see on the video. I upload the GPS data from my Garmin 796 to CloudAhoy, which will give me WAAS accuracy.

I'll also have a camera pointed at the instrument panel so I can review things like pitch angles and speeds after the flight.

Measuring this seems very difficult.  You will need identical days for wind, temperature, pressure, and the weight of the plane.  I know my plane gets off the ground much faster on a cool day with a 10 kt head wind.     --Maybe you can use the charts in the manual and scale for the differences.

[PTK]

PowerFlow inside a LoPresti cowl is tight, but a great combination on a 201. Add a Top Prop (or a new MT prop), and the usual speed mods from LASAR, and you have a real hot rod.

 

How do you define "real hot rod?" What's the delta compared to without these mods?

The way I do the math it's a questionable savings of ~6 minutes on a 300 nm flight. Slightly less on a shorter flight and slightly more on a longer one.

I can't justify the costs of all these mods for a few negligible minutes.

The J is the ultimate Mooney. Why mess with it?

Edited October 20, 2015 by PTK

[pfactor]

Measuring this seems very difficult.  You will need identical days for wind, temperature, pressure, and the weight of the plane.  I know my plane gets off the ground much faster on a cool day with a 10 kt head wind.     --Maybe you can use the charts in the manual and scale for the differences.

Yeah, the tests will certainly be done under different weather conditions. I think all I can do is collect what the actual conditions are on both days.

[Piloto]

 

How do you define "real hot rod?" What's the delta compared to without these mods?

The way I do the math it's a questionable savings of ~6 minutes on a 300 nm flight. Slightly less on a shorter flight and slightly more on a longer one.

I can't justify the costs of all these mods for a few negligible minutes.

The J is the ultimate Mooney. Why mess with it?

One that is really noisy.

[OR75]

it is up to the installing IA to make a determination of compatibility.  

probably easy and obvious decision most of the times like for avionics 

for powerplant items , probably not so obvious 

[Hector]

I don't have a good objective way to do this.

Phil

If you have an iPhone look for the app SPLNFFT. It is one of the best sound meters for phones out there. It is somewhat technical but it will record average and highest db(a) among a bunch of other stuff.

[Two Oh One]

how does one determine the compatibility between all the STCs ?

power flow and new cowling ?

power flow and MT or Hartzell prop ?

just wondering since I recall seeing someone here having to resell a component because of STC compatibility (I cannot recall if it was a prop or a power flow) 

I know that the STC approved model list for my EDM 900 specifically listed compatibility with a J equipped with the exact STC for my MT prop. Easy determination there.

[aaronk25]

The power flow isn't any noise reduction inside than the stock exhaust best I can tell.

P.f. Is worth 5kts or so maybe more down below 9k. And yes only a kt or so is free the rest comes of the kts require a little more fuel. The best thing about the power flow it lowers CHT by 20-30f and allows the choice to use more available h.p. in cruise should it be desired.

[jetdriven]

5 knots?  That's like 30-40 HP. I can see near that on a C model with the exhaust they got but not a J. I can't see it's very much better and certainly not 5 knots worth....