MT prop upgrade on a 231

[Ethan]

49 minutes ago, carusoam said:

Terrible assumption…. 

All MSers know….

That sliding their chair back in flight is…

• More comfortable…
• Better B in the WnB calculation….
• More Kias….

Remember…

The tail plane is generating negative lift…. To balance the plane in flight…

The more it needs to pull down, the more drag it generates…
 

Everyone has a WnB calculator…

Experiment with the calculations to see how far back you can move the Cg…..  before it falls out the back of the graph…

Make sure you know that the WnB calcs and graphs apply to your current plane’s weight…

Don’T load the plane up with people the first time you experiment with WnB… bags of sand tied in place work pretty well too…

 

Pp thoughts only, not a CFI…

Best regards,

-a-

Well, on a good day I’m 5’ 7”. I slide the seat all the way up unless I’m wearing my clogs. With clogs, I’m one notch back but still way forward.

I also like my feet on the rudder pedals during flight so I can keep the airplane flying straight - for efficiency. In cruise, I find the airplane likes a scosh of left rudder to center the ball nicely.

I guess to max out on speed I’ll have to throw an anvil in the trunk.

[Will.iam]

Or add a yaw damper. It has rudder trim so you can slide the pilot seat way back. 

[carusoam]

28 minutes ago, Ethan said:

Well, on a good day I’m 5’ 7”. I slide the seat all the way up unless I’m wearing my clogs. With clogs, I’m one notch back but still way forward.

I also like my feet on the rudder pedals during flight so I can keep the airplane flying straight - for efficiency. In cruise, I find the airplane likes a scosh of left rudder to center the ball nicely.

I guess to max out on speed I’ll have to throw an anvil in the trunk.

the preferred anvil… is a box of tools and spare parts…

For rudder trim… you can make one adjustment (pick your favorite loading)….  (I have the rudder trim switch, which is really cool if you can add one…)

There are also rudder pedal extensions if you want to be 1.5” to 3” further from the panel…. It’s all about leg length, not so much neck length…

 

Its all about getting to the back line with the minimum useless weight being added…

Its not a lot of kias…. More of an engineering exercise… because you can. 

Flying around at 10k’ agl… the air is pretty smooth most often.  Not a lot of rudder pedal action going on…

I bet one of those GFCs with the rudder anti tail wag feature would really help…

 

PP thoughts only, not a CFI or mechanic…

Best regards,

-a-

[Z W]

Our K was very out-of-rig when we got it.  Would drop a wing pretty badly to the right when you released the yoke.  Handled poorly in slow flight, requiring big corrections.  Yaw was a half-ball to the left in level cruise.  Had it re-done by a Mooney specialist shop in Florida.  They fixed the rigging on the gear doors, flaps, and ailerons.  Now it flies beautifully hands-off, ball centered, no wing drop and nice and solid in slow flight.  I'm told this job requires special rigging boards not found in most shops.  There are other threads on it here.

After that, we gained maybe 1-2 knots in cruise, if any.  Worth it but not for the speed gain.

I would check (and share here) your power settings.  You're missing 10-15 knots somewhere, and I would find it hard to believe it's your rigging or prop.  At 10k MSL, 28" MP, 2500 RPM, and 13.5 GPH, I see about 165 KTAS.  If you're using similar settings, I would suspect your pitot-static system or airspeed indicator gauge.  The old analog gauges are notorious for being inaccurate.  Easy to check that with a 3-way GPS speed check (fly three different headings opposite more or less from each other at the same altitude and power settings, record your speed once the plane settles in, then calculate the average of the three to remove the wind factor).  We gained 5kts of indicated airspeed moving from an old analogue ASI to a digital panel.  Groundspeed stayed the same though, unfortunately.

I've never read anything to make me want to switch from our Hartzell aluminum 2-blade prop.

Good luck.

[Guest]

18 hours ago, WAFI said:

Quick question on the MT 3 blade on a M20J 201, does it remove the yellow arc (Vibration Range)? 

I looked at their website. It does not mention any RPM restrictions.  Nor does it say that it eliminates them.  My guess is that there are none.

 

[KSMooniac]

2 hours ago, M20Doc said:

I looked at their website. It does not mention any RPM restrictions.  Nor does it say that it eliminates them.  My guess is that there are none.

 

The MT removes all restrictions on the J installation.  In fact, the STC paperwork instructs you to re-mark the tach, or at least add a placard.  When I installed my EDM-900, I sent the relevant data to JPI and got back a tach display with no yellow arc.

[WAFI]

2 hours ago, KSMooniac said:

The MT removes all restrictions on the J installation.  In fact, the STC paperwork instructs you to re-mark the tach, or at least add a placard.  When I installed my EDM-900, I sent the relevant data to JPI and got back a tach display with no yellow arc.

Very nice! Thanks for the info.

[khedrei]

14 hours ago, Z W said:

Our K was very out-of-rig when we got it.  Would drop a wing pretty badly to the right when you released the yoke.  Handled poorly in slow flight, requiring big corrections.  Yaw was a half-ball to the left in level cruise.  Had it re-done by a Mooney specialist shop in Florida.  They fixed the rigging on the gear doors, flaps, and ailerons.  Now it flies beautifully hands-off, ball centered, no wing drop and nice and solid in slow flight.  I'm told this job requires special rigging boards not found in most shops.  There are other threads on it here.

After that, we gained maybe 1-2 knots in cruise, if any.  Worth it but not for the speed gain.

I would check (and share here) your power settings.  You're missing 10-15 knots somewhere, and I would find it hard to believe it's your rigging or prop.  At 10k MSL, 28" MP, 2500 RPM, and 13.5 GPH, I see about 165 KTAS.  If you're using similar settings, I would suspect your pitot-static system or airspeed indicator gauge.  The old analog gauges are notorious for being inaccurate.  Easy to check that with a 3-way GPS speed check (fly three different headings opposite more or less from each other at the same altitude and power settings, record your speed once the plane settles in, then calculate the average of the three to remove the wind factor).  We gained 5kts of indicated airspeed moving from an old analogue ASI to a digital panel.  Groundspeed stayed the same though, unfortunately.

I've never read anything to make me want to switch from our Hartzell aluminum 2-blade prop.

Good luck.

Yes, I forgot to include my power settings.  I run 28" MP and 2500 RPM and 13.5 GPH just like you stated.  I have the intercooler and Merlyn wastegate.  My panel is decked out.  Full G500Txi, with most of the bells and whistles so I trust the numbers.  Pitot static was just done this spring at a reputable shop and also done 2 years ago when the panel was done.  Nothing changed after either.  TAS calculator is consistant at 10k feet I see 150kts every trip.  Thats with 2 medium sized guys in the front and a full bagage compartment.  It also gives me wind direction calculator and ground speed and it works out if I do the math.  If I run 29" I can  get a few extra knots TAS.  It has been like that since I got it 5 years ago and been through several shops.  Like I said, it rolls ever so slightly to the right with hands off in flight but not much.  I'm not sure what else I can do.  It has all the gap seal kits that were availalble, but it does not have the one piece belly.Other Media

 

Thanks for all the input on the prop.  Especailly the detailed response from @philiplane Making me think it is unlikely to be worth an upgrade.  Come to think of it, the MT on my friends 182 that I really liked so much did have a crack on the trailing edge.  It was just out of warranty.  A local shop charged around $1500 CAD to send it off and have it fixed.  They did a good job but you can still see where the repair was made.  Perhaps more trouble than they are worth.  I haven't had to do anything to my 2 blade McCauly aside from a file down a couple times a year that takes 20 minutes.

 

Edited September 2, 2022 by khedrei

[khedrei]

22 hours ago, carusoam said:

 

Are you thinking this is a rigging issue?  This is more of an everyday flight in different regimes with different loads issue….

If the elevator was always nicely aligned… we would be building gorilla arms because the trim isn’t working…

Another note to go with this… as the tail gets canted forwards…. The elevator may move in the opposite direction… (it does on the ground for the Mooneys with spring bungees…. Like the M20C… the LBs don’t have the springs and elevator sags on the ground….

PP thoughts only, not a mechanic…

Best regards,

-a-

I don't think it's a rigging issue.  The tail was out of rig when I first test flew it after the avionics install.  The avionics guy called in a specialized shop to rig the tail and it was fixed.  I understand that with different loading senarios at the high end of the speed envelope, the tail would be movable into a position which could eliminat most (if not all) of the requirment to have the elevator displaced.  Again, I am not an engineer nor a mechanic.  I guess it can't move quite that much?  And yes, to answer your question, we see the counter weights of the elevator, not the elevator itself.

It does not seem like the plane is out of rig.  It just seems like I am going too slow.