Performance M20C with Hartzell 3 blade propeller HC-C3YR-1RF/F7282

[Urs_Wildermuth]

3 hours ago, bluehighwayflyer said:

The great American philosopher, Mike Tyson

I think I know what you mean. Of course there is always the unexpected and it's also part of the fun.

[Shadrach]

This thread seems so odd to me. I don’t remember the last time I used a POH to set power. My airplane was delivered with a placard against continuous operation below 2350 and above 1950. I’ve never felt that I was missing out by not being able to operate at 1951, 2349 or some area in between. I would never choke my engine back just because the day that I happen to be flying wasn’t meeting the particular numbers at a particular altitude in the table of a 50 year old book.  Seems silly to get worked up about not having a 50 year old of piece of paper with your planes serial number on it to set a power with a 50 year old MP gauge. Both items are of dubious precision, and the power flow exhaust negates the original imprecise figures. 

[Urs_Wildermuth]

1 hour ago, bluehighwayflyer said:

Urs just enjoys and finds gratification from demonstrating the owners manual performance tables.

Well, I guess that is in my dispatcher's blood. During my airline time I came across some really challenging datasets which needed to get into computer generated flight plan or weight and balance models. I probably was one of the first who managed to get a DC3, Caravelle and a TU154M into a electronic load and balance program (in the 1980ties mind) from simple graphic data. Later we did performance evaluations for high fidelity flight sim products. And if you think I am picky about numbers, don't ever mess with that crowd

So I am not simply some sort of number freak, but I like to be on the precise and safe side when doing the docs for my airplane and I want to have a pretty good off hand idea what it can do. But primarily I want a dataset I can safely put into flight planners and which actually work. No point in taking a default C performance model and wondering why it's calculating wrong. For what I use, this requires a complete 75/65/55% power table plus some other goodies which for now remain the same (time fuel distance to climb/descend). That is all.

And btw: At least in Switzerland, we are strongly encouraged to have an Operational Flight Plan available in case of ramp checks. In Europe many people still carry a paper briefing package for that purpose. Myself, i also find it easier to work with. But as you say, each to his own. In order to generate an operational flight plan, data needs to have some semblance of accuracy, otherwise in the case of an incident or heaven forbid accident, the authorities will have a field day proving you negilgent in flight preparation.

 

[Shadrach]

7 minutes ago, Urs_Wildermuth said:

Well, I guess that is in my dispatcher's blood. During my airline time I came across some really challenging datasets which needed to get into computer generated flight plan or weight and balance models. I probably was one of the first who managed to get a DC3, Caravelle and a TU154M into a electronic load and balance program (in the 1980ties mind) from simple graphic data. Later we did performance evaluations for high fidelity flight sim products. And if you think I am picky about numbers, don't ever mess with that crowd

So I am not simply some sort of number freak, but I like to be on the precise and safe side when doing the docs for my airplane and I want to have a pretty good off hand idea what it can do. But primarily I want a dataset I can safely put into flight planners and which actually work. No point in taking a default C performance model and wondering why it's calculating wrong. For what I use, this requires a complete 75/65/55% power table plus some other goodies which for now remain the same (time fuel distance to climb/descend). That is all.

And btw: At least in Switzerland, we are strongly encouraged to have an Operational Flight Plan available in case of ramp checks. In Europe many people still carry a paper briefing package for that purpose. Myself, i also find it easier to work with. But as you say, each to his own. In order to generate an operational flight plan, data needs to have some semblance of accuracy, otherwise in the case of an incident or heaven forbid accident, the authorities will have a field day proving you negilgent in flight preparation.

 

See, there is the problem I failed to see. US GA pilots are cowboys that just take to the skies and hope for the best.  I'm pretty sure my plane will run for another hour on my machismo alone. 20 years of XC flying without using POH power tables have made me complicit. How else could one plan a flight?  I'd likely die flying overseas...if they even let such a scofflaw in the cockpit.

[Urs_Wildermuth]

Well, Ross, you probably fly a lot more than I do. And in the US, you have countless airfields and airports where you can decide to land and fuel and where you can do so without prior permission (often up to 48 hours ahead) and similar stuff. Clearly, that makes it a lot easier.

I would not dream of calling anyone names because of that!

Also, with the fuel prices we have, we really aim to fly as efficient as we can. And personally I fail to see how to achieve that without proper performance data. Quite often it turns out that what people THINK is quite different from what transpires if someone who knows performance looks at it. 

Anyway, all I wanted to get in this thread is some information what other people who have this STC get in terms of figures.

 

[Urs_Wildermuth]

7 minutes ago, bluehighwayflyer said:

In terms of VFR flight planning, here in the U.S. FAR 135.615 does require us to “document (our) VFR flight planning procedures in (our) operations manual”, but I have never heard of that having been interpreted so strictly as to require us to set power solely by reference to our POH performance tables.  

Of course not. Most people will eventually get a preferred setting they use all the time. So do we in most cases. Yet that setting has to be covered in the database in Foreflight or whatever you use to make sense. For most of our planes including the stock C model, those models are readily available, therefore people feed it into their Ipad and go. Nothing wrong with that in the least, or even with the more basic approaches, as long as people are familiar with them. The way you do this does not matter as long as they coincide.

19 minutes ago, bluehighwayflyer said:

ou, even in the case of my previous M20J’s POH, which was vastly superior to the owner’s manual of my current C model, there were so many obvious minor errors in the performance tables if you really examined them that I would never want to rely on them to their limits.

I know. Let me tell you that for example there are much worse "Range" figures in other makers POH, even though much better "organized" but just as wrong. I've been using a different algorythm for a long time to generate Range figures. And guess what, they are quite a bit smaller than POH figures.

You know, I really don't want to make things more difficult or to as the saying goes in Switzerland "make a doctorate out of it". The main thing is to get some basic data to start with. The rest is easy. And the aim is to provide something which the other pilots can use for information which looks and is easy to use, such as the old tables printed on the sunscreen of most Pipers. I had all that for the C as it was and now it needs updating, that's all that is to it.

I REALLY don't want to tell anyone else how to go about things, really, all this is about getting some data. I am quite happy with the results, as they confirm my gut feel: 1. we know that the take off RPM/MP is way too low and we know as well that there is at least someone who gets the figures he expects with the same prop. That means for me we need to find out if our installation is faulty or what is going on. And then we will figure out the rest.

[Shadrach]

5 hours ago, Urs_Wildermuth said:

Well, Ross, you probably fly a lot more than I do. And in the US, you have countless airfields and airports where you can decide to land and fuel and where you can do so without prior permission (often up to 48 hours ahead) and similar stuff. Clearly, that makes it a lot easier.

I would not dream of calling anyone names because of that!

Also, with the fuel prices we have, we really aim to fly as efficient as we can. And personally I fail to see how to achieve that without proper performance data. Quite often it turns out that what people THINK is quite different from what transpires if someone who knows performance looks at it. 

Anyway, all I wanted to get in this thread is some information what other people who have this STC get in terms of figures.

 

I may or may not fly more than you, but I am confident that the view from your cockpit is usually superior.  I inferred from your comment that my flight planning might be less than adequate and may be viewed by the Swiss authorities as "negligent". That may indeed be the case.

From the outset you seemed resigned that the utility of your airplane was now in jeopardy.  Using phrases like: 

 "total killer", "no more long range cruise" "loss of most of the performance information we have in the POH!"  "65% power is not possible below 7500 ft using the POH, let alone 55%..." or "That means pretty much no long range cruise, worse range and so on."

To read the above, it appeared that you needed to use your POH settings for your airplane to have utility. They don't need to be accurate, you just need to be able to use the settings.  That seemed dramatic to me. Especially given that those numbers are imprecise in the first place and less so with your new exhaust.  My point from the outset is that you need to derive your own data from flying your machine as it is currently configured.   Powerflow exhausts work but they are not magic. All other things being equal, the increase in volumetric efficiency means higher power and therefor higher fuel burn than the POH numbers.  Indeed, what people THINK is often different from what transpires, which is why some basic flight testing to actually see what transpires is the best course of action.  Given the quest for efficiency and precision, I would guess you have an engine monitor and fuel totalizer. Would it not be acceptable to take a day and fly POH TAS for a corresponding power setting and see what real world fuel burn looks like?  Do the authorities even care about power percentages? Is TAS and fuel burn by altitude not adequate?  One need not fly every altitude and setting, surely some interpolation is possible.

I meant no disrespect.  Having to change you SOP across the board is a pain but in the scheme of what you've been through with this prop strike, it does not seem like a huge burden. Perhaps it's just that it is another in a series of setbacks and you're tired of setbacks.  If that is the case, I can certainly understand and I am sorry that it's been difficult.  I hope you get things sorted out and are back in the air soon.

[Urs_Wildermuth]

So after about 10 hours into the new prop, we now are working with a constant degradation of 5 kts in comparison to what the 2 blade prop was, with identical fuel flow. As most of this 10 hrs were recurrency training, we donˆt really have proper cruise data up high yet. 

If this confirms once we get to fly more, it would mean quite a significant loss (5 kts means an average planning speed of 135 KTAS rather than 140 we had before) but not as dramatic as 8 or 10 kts. With a 4 hour range, it would kick some 20 NM off the plannable rage and a cost increase of about 6% over a 500 NM distance. Not nice, but we will have to live with it. 

Take Off RPM and MP is higher now, I have no exact figures reported to me yet, but it appears the adjustments did something. Take off performance is notably better. 

One other bit is Weight and Balance... the new prop installation is now approx 10 kgs heavier and causes a massive CG movement to the front. I have to play with this a bit but all in all, this will further restrict range as both Weight and CG are now critical. For training flights with 2 up front and full tanks, we will need some 30 kgs of ballst in the baggage compartment to get it back into envelope. 

[Hank]

My notes are still in the plane, but I found a surprising speed difference at 7000 msl, which is right at the border between two of my common settings.

To my surprise, 22"/2400 was noticeably faster than 21"/2500. And yes, I have the 3-blade Hartzell. Seems indicated airspeed went from 135 mph to 142 mph. 

Hope you get some of your lost speed back. And yes, takeoff and climb is nice!

[Urs_Wildermuth]

On 8/3/2022 at 11:45 PM, Hank said:

To my surprise, 22"/2400 was noticeably faster than 21"/2500.

That on the other hand is a very useful bit of information. Duely noted.

If you ever get the time to look over your notes, I'd be very interested indeed.

 

[carusoam]

Hey Urs!

Long time no see.

I completely missed this whole thread.

Best regards,

-a-

[carusoam]

Avoiding harmonics was a big challenge for the O360 and it’s original two blade prop…

Going Hartzell 3-blade was supposed to remove the avoidance rpm ranges…. So I thought….

Those ranges are very much engine/prop combinations…

Soooo…. Make sure you have the latest STC details for the prop engine combination…

Hartzell is pretty easy to contact for stuff like this…

 

If having the last POH produced (1977) for the M20C helps… they are available by electronic copies…. Via MSC/factory….

I think Hank’s POH is in the download section… 

Briefly… make sure you aren’t accidentally keeping limits that no longer apply…

Best regards,

-a-

 

[Urs_Wildermuth]

17 hours ago, carusoam said:

Briefly… make sure you aren’t accidentally keeping limits that no longer apply…

Hi there,

Well, we got the prop in June from MT Propellers new from Hartzell with the STC. So I really assume it is the current one, but I'll check it.

Given that on the test flight we flew 2300 RPM in cruise and found it a bit strange, I guess there is a reason for it. I have yet to test the configuration with 2400 RPM, but I guess that was what this restriction is for.

I got some feedback on other channels (initiated by this here post though) which may be useful too. Will have to see.

If someone has a noise certificate based on real world measurements for this configuration, it would be highly appreciated. It appears Hartzell simply issue a Chapter 10 certificate stating it is below the maximum db(a) but does not say (probably because nobody knows) the exact values. I am considering doing a noise measurement flight next year but if someone has the data, I might be able to avoid that.

 

 

[Hank]

32 minutes ago, Urs_Wildermuth said:

Hi there,

Well, we got the prop in June from MT Propellers new from Hartzell with the STC. So I really assume it is the current one, but I'll check it.

Given that on the test flight we flew 2300 RPM in cruise and found it a bit strange, I guess there is a reason for it. I have yet to test the configuration with 2400 RPM, but I guess that was what this restriction is for.

So is your new 3-blade prop a Hartzell or an MT?

I cruise my Hartzell 3-blade at 2300 only up to 3000 or 3500 msl; then 2400 up to 7000 / 7500 msl, and 2500 above that, to keep my Key Number to 46 (= 65% power).

[Urs_Wildermuth]

34 minutes ago, Hank said:

So is your new 3-blade prop a Hartzell or an MT?

Hartzell. The distributor in Europe (or at least where I live) is MT Propellers.

 

37 minutes ago, Hank said:

I cruise my Hartzell 3-blade at 2300 only up to 3000 or 3500 msl; then 2400 up to 7000 / 7500 msl, and 2500 above that, to keep my Key Number to 46 (= 65% power).

Understood, thanks.

[Raptor05121]

Thats interesting youre down to 135KTAS with the prop. I have the same prop on an engine with 5800TT/2600SMOH and the last time I did a "speed run" at 8500 I got 143-147KTAS depending on how I had the mixture leaned. How heavy is your plane? Has it been rerigged recently?

Edited November 7, 2022 by Raptor05121

[Urs_Wildermuth]

20 hours ago, Raptor05121 said:

Thats interesting youre down to 135KTAS with the prop. I have the same prop on an engine with 5800TT/2600SMOH and the last time I did a "speed run" at 8500 I got 143-147KTAS depending on how I had the mixture leaned.

We will have to retest the whole thing. What kind of power setting did you use? FT/2500RPM? And can you roughly remember the fuel flow?

[carusoam]

The MT props really do have a lower outside sound….

At a Mooney fly-in… there was a mass departure…. A line of various Mooneys departing one after the other…

300hp 2700rpm are powerfully loud!

Somebody went by with his 300+hp Rocket with the funky four bladed MT prop…. which was much less intimidating…. 
 

For Europe, the MT makes a lot of sense….

The composite construction must be good a deadening sound vibrations…

Best regards,

-a-

[Urs_Wildermuth]

8 hours ago, carusoam said:

The MT props really do have a lower outside sound….

It is a Hartzell. The MT Props do not have a STC for the C and G model, only for the injected 200 hp engines in the E, F, J and all the others upwards.

MT are not only a manufacturer, they also sell other people's products as a shop in Europe and they also overhaul props of any kind.

A few years ago, they did a great job on my now ruined 2 blade Hartzell.