MT 4 Blade Pirep

[SkepticalJohn]

It was just north 32k total - that scan was the final bill. A large part of it (~9k-10k, I'd have to look) was the beta/reverse thrust design and approval process. I think your M20M is an STC, the M20K install is a field approval.

I'm hoping for a shorten landing distance, lightened weight/increase useful, and a further aft CG. My engine is in a shop right now for an overhaul. The prop will go on with the fresh engine. So unfortunately, I won't have a real apples to apples performance comparison as I'm changing 2 variables at the same time. Landing distance should still be apples to apples, though.

On the cowling removal for the 4-blade, do you position the prop "x" or "+"?

John

Edited January 20, 2021 by SkepticalJohn

[GeeBee]

After seeing my buddies crash in a Murphy Moose, when his MT prop governor went into reverse airborne, (much to the chagrin of MT) I would be reluctant to go that route.

 

[carusoam]

Looking forwards to the pirep on the beta system!

+1 for knowing how the beta system fails...

Something i didn’t like so much about the Rocket’s gov failure to increase pitch, instead of flatten pitch...

Improves glide if the engine croaks...

Kills thrust if the gov croaks...

Really short landings would be really interesting...

Best regards,

-a-

[N442PT]

I am so glad to get some feed back on the M&T 4 blade. Awesome PIREP 

[KLudwick]

Very interested in hearing a future PIREP on the beta/reverse operation!

[SkepticalJohn]

PIREP on the reserve thrust and 4-bladed prop on my Rocket:

It's much more handy than I thought it'd be. There have already been three times where I fueled (self-serve) and some yayhoo pulled in the opposite direction, blocking me from pulling straight out. I fire up the aircraft, put it in reverse, and back out.

There was another time, I taxied to my buddy's hangar home on a dead-end taxiway, did a three point turn at the end, and avoided having to pull the aircraft by hand.

I landed in Tulsa at night and the tie down parking was almost full. I pulled up in front of the spot I wanted to park and backed her into the spot.

All of those cases, I used my backup camera and looked out the windows to assure I didn't bump into anything.

The original idea for that feature was to shorten landings. I don't know how much it shortens landings as I haven't done back to back landings for an apples to apples comparison yet. I can say, the prop slows the airplane down a bit faster than the brakes can. If you also use brakes AND revere during landing, it stops at a pretty high rate of giddieup. I'll try to do some comparisons when I get a chance for empirical data instead of seat of the pants, so more to follow. 

It seems to be one of those things you didn't know you wanted/needed until you have it. Here's a video of the first time I played with it.

we all got out of the plane afterwards and had the same opinion, "that is soo handy, I can't believe that every plane doesn't have it!"

I answered my previous question, on how to decowl the plane with the 4-bladed prop. Position the blades in an "x', not a "+", and as Erik mentioned before, drop it straight down straight down one side at a time on something soft like a blanket and drag it out to the side.

There was a comment before to the effect, you need even multiple blades on your plane.. 2 blades for a 4 cylinder, 2 or 3 blades on a six cylinder. When the mechanic balanced this setup on the airplane, it came out at 0.02IPS. That's turboprop-like balance. My last plane (231 with 2 blades) was 0.2 IPS, balanced. This new prop on the Rocket is silky smooth.

[aviatoreb]

2 hours ago, SkepticalJohn said:

PIREP on the reserve thrust and 4-bladed prop on my Rocket:

It's much more handy than I thought it'd be. There have already been three times where I fueled (self-serve) and some yayhoo pulled in the opposite direction, blocking me from pulling straight out. I fire up the aircraft, put it in reverse, and back out.

There was another time, I taxied to my buddy's hangar home on a dead-end taxiway, did a three point turn at the end, and avoided having to pull the aircraft by hand.

I landed in Tulsa at night and the tie down parking was almost full. I pulled up in front of the spot I wanted to park and backed her into the spot.

All of those cases, I used my backup camera and looked out the windows to assure I didn't bump into anything.

The original idea for that feature was to shorten landings. I don't know how much it shortens landings as I haven't done back to back landings for an apples to apples comparison yet. I can say, the prop slows the airplane down a bit faster than the brakes can. If you also use brakes AND revere during landing, it stops at a pretty high rate of giddieup. I'll try to do some comparisons when I get a chance for empirical data instead of seat of the pants, so more to follow. 

It seems to be one of those things you didn't know you wanted/needed until you have it. Here's a video of the first time I played with it.

we all got out of the plane afterwards and had the same opinion, "that is soo handy, I can't believe that every plane doesn't have it!"

I answered my previous question, on how to decowl the plane with the 4-bladed prop. Position the blades in an "x', not a "+", and as Erik mentioned before, drop it straight down straight down one side at a time on something soft like a blanket and drag it out to the side.

There was a comment before to the effect, you need even multiple blades on your plane.. 2 blades for a 4 cylinder, 2 or 3 blades on a six cylinder. When the mechanic balanced this setup on the airplane, it came out at 0.02IPS. That's turboprop-like balance. My last plane (231 with 2 blades) was 0.2 IPS, balanced. This new prop on the Rocket is silky smooth.

Wow - that is really really cool!  Why doesn't every plane have reverse pitch?!!

Can you still do flat pitch for maximum glide in an emergency?

What was the weight difference relative to the McCauley you switched out?  My guess is it is a bit lighter than the McCauley but a bit heavier than the normal adjustable prop that I got from MT.  I took off about 35lb.

Yeah - aint they smooth?!!!

[SkepticalJohn]

It doesn't go feather or low pitch, but rests against the high pitch stops when the oil pressure is off. Like this...

35lbs is the same weight savings I experienced over the stock Rocket prop/ spinner (both of which I still have of anyone is looking for them). So apparently our weights are similar.

I don't remember if I told you, Erik, but your prop was the motivation I had for doing mine. Thanks for blazing that trail!

[SkepticalJohn]

My buddy just posted a video taken from one of his security cameras of the dead end taxiway 3 point turn I mentioned in my PIREP.

 

[A64Pilot]

The high pitch stops would be best for less drag in an engine off scenario, more likely to stop and even if windmilling, it would be at a lower RPM so less energy taken from the aircraft., cause of course the energy to windmill a dead engine comes from somewhere.

High pitch stop when off is often used for aerobatic props as if there is a loss of oil pressure, prop increases and controls engine RPM, going flat could cause an overspeed, especially at high power and speed, it’s similar to throwing a car into low gear at high speeds.

I assume you can maintain flight at high pitch, cause that’s where it’s likely to go if the governor fails.

Be very careful going into Beta before your on the ground as it can block airflow over the tail, smart Ag guys wait until the tailwheel is down, cause the rudder has little authority in Beta

I assume you have an electric switch to control pitch and not a cable like the rest of us?

This is what can happen in an extreme case if the governor loses oil pressure, listen the the engine, it’s astonishing how fast the RPM went once the MT prop exploded from overspeed, this is a prop that goes to low pitch of course

https://youtu.be/DhyEnqudx8M

Sounds like an air impact wrench to me.

Edited March 30, 2022 by A64Pilot

[SkepticalJohn]

There are 4 safeties to prevent accidental reverse:

- a mechanical lockout in the hub that unlocks <1400 RPM

- an airspeed sensor, MT included, that disables reverse above 60 knots. 

- a "reverse arm switch" on the left side of the panel, beneath the G5.

- a trigger on the pilot's yoke to activate reverse.

Otherwise, the cockpit controls are the same as every other 252/Rocket - same throttle, prop and mixture knobs. The procedure is, arm the panel mounted switch before landing, after landing and the nosegear is on the ground, bring throttle below 1400 if it isn't already, squeeze the trigger on the yoke, prop flips to -14° pitch, use brakes and push throttle forward as far as needed to adjust the amount of reverse thrust (which feels weird to do after you just landed and don't intend to takeoff again), release trigger once slowed and taxi like every other aircraft. 

[aviatoreb]

48 minutes ago, SkepticalJohn said:

It doesn't go feather or low pitch, but rests against the high pitch stops when the oil pressure is off. Like this...

35lbs is the same weight savings I experienced over the stock Rocket prop/ spinner (both of which I still have of anyone is looking for them). So apparently our weights are similar.

I don't remember if I told you, Erik, but your prop was the motivation I had for doing mine. Thanks for blazing that trail!

My pleasure skeptical John!  I am really pleased to see you tried an even more advanced option with the beta!  I love hearing how such things go.  I bet you have some really short runway performance now.  I think my rocket was the first one with the 4 blade MT and we had to work out a lot of measurement and fitting issues - I think it was 7 years ago?  Maybe more.  With the rocket power it can certainly take off short but I would be shy to go into shorter runways for the lading and stopping issue which you have now solved.  And anyway how unique and cool!  Plus your plane looks maaaavelous!

Edited March 30, 2022 by aviatoreb

[aviatoreb]

4 minutes ago, SkepticalJohn said:

There are 4 safeties to prevent accidental reverse:

- a mechanical lockout in the hub that unlocks <1400 RPM

- an airspeed sensor, MT included, that disables reverse above 60 knots. 

- a "reverse arm switch" on the left side of the panel, beneath the G5.

- a trigger on the pilot's yoke to activate reverse.

Otherwise, the cockpit controls are the same as every other 252/Rocket - same throttle, prop and mixture knobs. The procedure is, arm the panel mounted switch before landing, after landing and the nosegear is on the ground, bring throttle below 1400 if it isn't already, squeeze the trigger on the yoke, prop flips to -14° pitch, use brakes and push throttle forward as far as needed to adjust the amount of reverse thrust (which feels weird to do after you just landed and don't intend to takeoff again), release trigger once slowed and taxi like every other aircraft. 

I would definitely be careful though letting any other pilot fly that plane without a very thorough briefing - even a very rocket savvy pilot like me isn't safe without an extra special prop briefing.

How very cool!

[amillet]

Parallel parking next?

[SkepticalJohn]

3 hours ago, aviatoreb said:

I would definitely be careful though letting any other pilot fly that plane without a very thorough briefing - even a very rocket savvy pilot like me isn't safe without an extra special prop briefing.

How very cool!

One of the aircraft I fly at my military job has reverse - C12 (king air 200). Their (CAE, because flightsafety lost the contract) brief was no reverse below 40 kts, to include no backing up. They said if you DO use it to back up, don't hit the brakes or you'll slam the tail on the ground. That critter sets pretty high on long landing gear.

I haven't used the brakes yet, backing up in the Rocket. It sets pretty low to the ground and I think it'd take some aggressive braking to drop the tail. I don't plan on testing that. Mike Patey used his reverse to put his plane, Draco, in the hangar. I'll use my tug and not test that either.

If any of y'all are headed to SUN-n-FUN, my Mrs and I plan on being there a couple days and would like to put faces with names.

[Andy95W]

This is so cool I had to check that today wasn’t April 1st.

[aviatoreb]

1 hour ago, SkepticalJohn said:

One of the aircraft I fly at my military job has reverse - C12 (king air 200). Their (CAE, because flightsafety lost the contract) brief was no reverse below 40 kts, to include no backing up. They said if you DO use it to back up, don't hit the brakes or you'll slam the tail on the ground. That critter sets pretty high on long landing gear.

I haven't used the brakes yet, backing up in the Rocket. It sets pretty low to the ground and I think it'd take some aggressive braking to drop the tail. I don't plan on testing that. Mike Patey used his reverse to put his plane, Draco, in the hangar. I'll use my tug and not test that either.

If any of y'all are headed to SUN-n-FUN, my Mrs and I plan on being there a couple days and would like to put faces with names.

Huh - I wouldn't run my prop in the hangar - it makes all the little things that are not tied down fly around!  In fact I close my hangar door before I start the engine.

I really don't mind using my tug to drag the plane around.

[SkepticalJohn]

Speaking of tugs... in the 444 days it took to the mechanics to rebuild this plane, I built a pretty handy tug I've been planning on doing a writeup on.

[carusoam]

Way cool John!

This thread wins the Best Technical Pirep of the Month!

 

One place I could see some extra value….

Our brakes are pretty ineffective above 50kias, as the plane is still light on its feet.

 

That’s the area where you might have a safety issue…

A very dynamic environment… for a few seconds traveling at high speeds…

 

For easy measurements… I use CloudAhoy connected to my portable WAAS source…

It can measure landing distances to the foot in accuracy….

 

I only ran off the end of a runaway once… Beta would have helped tremendously. 
 

+1 for watching Draco back-up into the hangar… guides, and cameras, would be a necessity for me…
 

Thanks for sharing the awesome details…

Best regards,

-a-

[Fly Boomer]

@SkepticalJohn you are a multi-talented builder!

[aviatoreb]

21 hours ago, SkepticalJohn said:

Speaking of tugs... in the 444 days it took to the mechanics to rebuild this plane, I built a pretty handy tug I've been planning on doing a writeup on.

WOW!  That looks fantastic!  Can I place an order now?  Do you take PayPal!!!

[jhbehrens]

On 10/20/2017 at 5:37 PM, MIm20c said:

The 310 stc is available through you MSC for around 5k. You will need a different governor and some changes to the fuel flow. Hartzell has a thin blade unit that is used on the acclaim s that is pretty efficient. Not familiar with the MT or if it’s FIKI certified if that’s an issue for you.  Other probably know a lot more than I do.

Not a new governor, just a modification - that can be combined with an overhaul

[aviatoreb]

3 hours ago, jhbehrens said:

Not a new governor, just a modification - that can be combined with an overhaul

I don't know if the MT 4blade is FIKI certified since I have the not-FIKI TKS system, but I can say that I do have the tks prop slinger on my MT 4 blade.  I would guess it would still be a FIKI setup.

[GeeBee]

According to literature and conversations I have had, it is FIKI.

 

[SkepticalJohn]

They gave me the option when i had them build my 4-blade. MT said they could make it with or without FIKI.