Cloud Nine's New Plane

[James_Dean]

101.5% is the MU-2’s redline...

Mine is 805*C or 1477 ft.lbs - whichever comes first. Game on.

 

[Ted]

More useless trivia on the MU-2, specifically on this F model:

Redline RPM: 101.5% RPM
Redline Torque: 60 psi
Redline EGT: varies from 500-550C, depending on OAT. Starting limit is 815C for 1 second.

At 100% RPM, propeller RPM is 2000. Some other TPEs used gearboxes with a 1591 RPM redline, but for the -1s it's 2000.

Certain TPEs used ITT rather than EGT. ITT has the advantage of having a fixed temperature. However, the ITT harness on the TPEs ends up being difficult (and thus expensive) to change if it fails. The EGT probes are just a bunch of probes sticking into the exhaust stream which you can actually see if you look inside the exhaust pipes. There's a table that determines max EGT allowance depending on the phase of flight and the OAT. The OAT gauge also has multiple bands on it to include EGT limits. Also, since you're looking at EGT vs. ITT, the numbers don't correlate as some of the heat is being turned into energy by the stages 2 and 3 turbine wheels, and it's also being diluted with secondary (cooling) air. On the Commander, for instance, the exhaust temps were ITT.

The torque being measured in PSI has to do with how the torque sensor works - it's literally a pressure sensor. Twin Otters also use torque in PSI as a measurement. For an engine guy like me I find it rather annoying, I'd rather have it in ft-lbs or %. On the Commander, the torque gauge was labeled as horsepower, but that horsepower was calibrated at 100% RPM. So if you ran at 96-97% in cruise (which is what's recommended) it was technically giving you an inaccurate horsepower number. But what matters is you respect the redlines and don't exceed them.

Because the engine inlet anti-icing uses bleed air, that will change your ITT/EGT some when you activate it as it changes the airflow through the rest of the engine.

I wonder where the screw to turn the boost up is...

 

[jsstevens]

[snip]
I wonder where the screw to turn the boost up is...

I called it! More power...

 

[Ted]

I called it! More power...

Technically I can just shove the power levers forward more, but that wouldn't be wise. Melting the hot section will get expensive fast.

And while I could try to do an upgrade to "Super 1s" or -10s (don't think I could do a -5/-6 upgrade) for more power (specifically more altitude performance), the cost is not only out of reach, but not worth it.

MT 5-bladed propellers COULD be worth it. I would expect their design to improve the ram air effect into the engines in cruise, plus just a better prop design that is likely going to prove better performing, especially in the higher altitudes. That's where I noticed the biggest improvement on the 414. However, these props are still working and thus that's a very, very low priority at this point.

Priorities for the aircraft itself are (not necessarily in order of importance):

1) Get the hot section done
2) Put the new tires on it (currently the nose tires are dry rotted and one of the mains is almost bald)
3) Get the plane 2020 legal
4) Get the plane set up the way I want it and start looking for weight reduction opportunities

 

[SCCutler]

5) Get Spike in the right seat.

 

[Ted]

5) Get Spike in the right seat.

While I'd be glad to have you along, I must point out that the regs don't allow anyone who hasn't taken the required training to touch the controls, even for SIC purposes.

 

[SCCutler]

5) Get Spike into SFAR training;
6) Get Spike in right seat.

 

[Ted]

5) Get Spike into 14 CFR Part 91 Subpart N training;
6) Get Spike in right seat.

FTFY, the SFAR no longer exists.

 

[SCCutler]

FTFY, the SFAR no longer exists.

We all knew what we were talking about - right?

 

[SixPapaCharlie]

So what is it that makes this plane more dangerous than any other plane?

 

[Croomrider]

So what is it that makes this plane more dangerous than any other plane?

High wing loading, spoilers instead of ailerons. Just a guess, I don't know for sure!

 

[Bill]

So what is it that makes this plane more dangerous than any other plane?

I'd tell ya, but I don't want to spoil the surprise!

 

[Ted]

We all knew what we were talking about - right?

Yep, and I've been calling it the SFAR as well. It'll take a solid 10 years for that to die, I'm sure.

So what is it that makes this plane more dangerous than any other plane?

The fact that I'm flying it, obviously.

There are a few factors that come into play.

The plane has the wing area of a 172 with a nearly 10,000 lb gross weight. Wing loading is 53 lb/sqft, which is almost the same as early Lears (54 lb/sqft). Everyone describes it as a jet with propellers, and you need to fly it as you'd fly a jet. The total wingspan is actually a bit less than the 414, at least it feels that way, and the wings definitely don't go back as far.

Because of this, the stall speed is very high. Clean at gross it's 101 KIAS. To make the stall speed lower and give good short field performance, they employed double slotted, full length fowler flaps with a maximum of 40 degrees. So at max landing weight with full flaps, stall speed is 77 KIAS. Much slower. Vmc also changes with flap settings, and is very high.

The plane needs to be flown fast. Per the book numbers, 150 KIAS on downwind (pretty much regardless of conditions), 120-125 or so on final, slowing to Vref which is somewhere in the range of 93-100 over the numbers. Did I mention you need to fly it fast? In a no-flap landing, you go over the numbers around 120 or so. All these numbers are from memory so I may be off by a bit. But like I said, go fast.

So the main problem you have is people will fly it too slow, thinking numbers like they're used to, or they'll incorrectly use the flaps. A big problem is if people lose an engine and retract flaps immediately, or if you do a go-around and retract flaps immediately. You need to achieve certain speeds before you retract any flaps, and you have enough horsepower to do so, even OEI. If I take off out of Houston at gross on an 85F day and lose an engine, the book says I should still have 600 FPM climb rate. But, I need to retract the flaps according to the schedule and at the right speeds.

Because of the full length fowler flaps, you can't have traditional ailerons - there's no place for them. The flaps literally go from the fuselage all the way to the tip tank. So, Mitsubishi's way around this was adding spoilers. The spoilers go up on one side at a time, are only about 2" long and then extend from the inner engine nacelle to the tip tank. But having spoiler creates some interesting handling characteristics (which I don't know all the details of yet - haven't done the training) and that can also create some situations where if the plane isn't handled correctly can crash.

Keep in mind that prior to 2005 or so when the SFAR came out, anyone who had the cash and a multi rating could go buy an MU-2, hop in it, and fly it. I could hop in a King Air, Conquest, or Cheyenne and legally fly it from the FAA's perspective. So you'd get people (and in some cases cargo operators) who'd buy these things up cheap, toss pilots in without any significant training, and the pilots would then crash the things when they came about some abnormal situation or else just fly the plane too slow in general.

As someone who likes flying fast, the plane is a good fit for me in that regard.

I looked at the performance charts last night to see about flying into Gaston's, and the plane will do it just fine. 20 degree flaps for short field, and come in light on fuel. Says it'll do the takeoff with 50 ft obstacle with room to spare. Mitsubishi achieved their goal - fast airplane with short field capability.

If you look at the background, Mitsubishi designed this as their first plane following the war effort, and really their only GA plane at the time. So unlike most GA manufacturers, they didn't go into it with preconceived notions of what a GA turboprop should look like or how it should fly, nor did they have another airplane to base the concept off of. Beechcraft based the King Air on the Queen Air, which itself has roots to the Twin Bonanza. Mitsubishi went in with a clean sheet design and experience on mostly larger aircraft, so they came up with requirements for what they wanted it to do and figured out how to make it happen.

Like any other high performance aircraft, though, it is intolerant of low performing pilots. See Lancairs, for example.

 

[Bill]

Like any other high performance aircraft, though, it is intolerant of low performing pilots. See Lancairs, for example.

This is a very interesting aircraft, Ted, fast with lots of character. I think you will get great pleasure in mastering and flying this one. I've enjoyed watching your progression through the various aircraft, and I have to say this is the first time I'm somewhat jealous of where you are! This is a thinking man's plane, you're gonna have fun.

 

[Ted]

This is a very interesting aircraft, Ted, fast with lots of character. I think you will get great pleasure in mastering and flying this one. I've enjoyed watching your progression through the various aircraft, and I have to say this is the first time I'm somewhat jealous of where you are! This is a thinking man's plane, you're gonna have fun.

Thanks, Bill.

I've always enjoyed learning and mastering a new aircraft. This one is different in a lot of ways, both by being a turboprop and also it being something you need to fly more like a jet than a more typical owner-flown turboprop. Laurie and I are both excited about it, even though she doesn't intend on doing the training. But I hope she'll fly up front with me when we go places together.

The steps I've had along the way have all been fun and all been planes I've learned from. The insurance likes me doing it this way, too. My insurance is actually quite reasonable on the MU-2 with my high multi time, having some turboprop time in the logbook, and plus plenty of pressurized time. The instructors I've talked to have said they don't think I'll have any problem transitioning with my background, but I'm certainly going into this with a lot of respect for the aircraft.

 

[SCCutler]

The record since the specially-mandated training (by whatever name) has proven that the plane is not at all dangerous - it simply must be properly flown.

It is, in fact, a fabulous and very robust design.

I never want to fly through a nasty storm in any plane - but if you had to choose one cabin-class turboprop to take to a challenging patch of air, it would be hard to argue against the MU2 as a first choice.

 

[Sam D]

101.5% is the MU-2’s redline...

Then I think you should name the plane Nigel.

 

[Bill]

Then I think you should name the plane Nigel.

Funny movie, a classic.

 

[Ted]

The record since the specially-mandated training (by whatever name) has proven that the plane is not at all dangerous - it simply must be properly flown.

It is, in fact, a fabulous and very robust design.

I never want to fly through a nasty storm in any plane - but if you had to choose one cabin-class turboprop to take to a challenging patch of air, it would be hard to argue against the MU2 as a first choice.

That is very true. The SFAR was perhaps one of the greatest successes in terms of reducing fatalities due to training. After the SFAR was implemented, the MU-2's accident rate went down to be lower than even that of the noble King Air. In recent years there have been 3 fatalities, although those pretty easily come down to "pilot failed to fly the plane correctly" rather than any fault of the plane itself.

There are also some interesting things that was determined about the MU-2 from all the examination it's received over the years. It was determined to be able to handle severe icing (obviously for limited periods of time, but still handle it). And come to think of it, I can't think of any in-flight breakups on record. The fatalities have from what I can tell always been from pilots ham-fisting the plane.

Basically, every time the design has been reviewed, the plane has been determined to have been certified correctly. In some cases there have been improvements made to recommended procedures and there is still debate as to what the best procedures are for certain cases, but in general it's:

- Fly it fast
- Use the flaps correctly
- Fly it fast

Then I think you should name the plane Nigel.

I was thinking of pointing out that the MU-2 always goes to 11.

 

[Cooter]

But having spoiler creates some interesting handling characteristics (which I don't know all the details of yet - haven't done the training) and that can also create some situations where if the plane isn't handled correctly can crash.

The big thing is that you have to keep in mind that left/right control inputs kill lift. It normally isn’t a big deal, but if you get slow or underpowered then it can make a big difference. Instead of rolling the aircraft around the longitudinal axis, it is causing one side to fall. Multiple left/right inputs, like in gusty conditions, can significantly affect performance when you get slow.

It may also affect how you fly OEI. It may be more beneficial to not counteract the yaw and instead accept it.

 

[Ted]

The big thing is that you have to keep in mind that left/right control inputs kill lift. It normally isn’t a big deal, but if you get slow or underpowered then it can make a big difference. Instead of rolling the aircraft around the longitudinal axis, it is causing one side to fall. Multiple left/right inputs, like in gusty conditions, can significantly affect performance when you get slow.

Correct. And you aren't supposed to bank into the good engine when OEI like you do with a normal twin.

 

[Cooter]

Correct. And you aren't supposed to bank into the good engine when OEI like you do with a normal twin.

Ha, you beat my edit. That’s what I was going to say, on a one engine go around, you fly it out sideways.

 

[EppyGA]

Ted, be sure to fly it fast.

 

[SixPapaCharlie]

This plane sounds a lot like a cirrus.

Only not as fast.

 

[Clark1961]

This plane sounds a lot like a cirrus.

Only not as fast.

Only in the air.

 

[Bill]

This plane sounds a lot like a cirrus.

Only not as fast.

In flight breakups dont count Lol.

 

[Ted]

This plane sounds a lot like a cirrus.

Only not as fast.

While I expect to handily lose against JT’s Conquest, I’ll take on the Cirrus with one engine feathered.

 

[mscard88]

I’ll take on the Cirrus with one engine feathered.

 

[James_Dean]

Can I get a consensus on what is correct- Moo-two or Mew-two?

While I expect to handily lose against JT’s Conquest, I’ll take on the Cirrus with one engine feathered.

I might win a drag race. I’m really curious to compare actual fuel consumption differences over a 400 mile round.

 

[Ted]

Can I get a consensus on what is correct- Moo-two or Mew-two?

I've been calling them "Moo-two"s for years, but I doubt that Mitsubishi as .

I might win a drag race. I’m really curious to compare actual fuel consumption differences over a 400 mile round.

Definitely, I'd be curious as well. My expectation is that the MU-2 will be more efficient on fuel with a minimal time penalty, being a short body with -1s. On the other hand, your higher climb rate will get you to efficient altitudes faster and if you pulled back the power to have the same cruise speed (and being able to go higher since my ceiling is FL250) you might eek out some benefits.

The 300+ KT MU-2s will burn around 85 GPH to do it. I'm expecting to see around 260ish on 400 pph combined (so around 58 GPH) from what I've heard talking to others.

As you said, game on.

 

[James_Dean]

I’ll fly down to MKC. Top off the tanks, take off 30 minutes apart, and we go see @SCCutler in Dallas who will document our landing time. We go have some dinner and run back. Top em off again and we should have everything we need to run the #’s.

 

[Ted]

Sounds like a plan. Max speed on the way south max economy on the way north?

 

[Tarheelpilot]

I wonder where the screw to turn the boost up is...

Speed levers full forward

 

[denverpilot]

I remember reading this accident report now what feels like forever and a day ago.

Keep that thing fast in ice, Ted. And boot maintenance sounds like it’s not something to defer very long but was allowed on this 135 certificate if flight into known icing wasn’t expected.

I remember this accident starting a very big discussion of icing in general as the NTSB worked with USAF to fly the MU-2 behind the ice making tanker.

This was a couple of years after the Roselawn ATR-42 accident and icing studies had been ramping up heavily in the intervening two years.

It’s interesting to read it now and think back to when that panel described and the physical relays and servos for the de-icing boot cycling stuff was still considered fairly state of the art.

Also interesting to think back to how difficult it was to get good icing forecast maps in 1996. Now they’re a tap away on my cell phone. Back then it was an on airport weather terminal to one of the weather providers or if you were a fancy pants you had dialup Internet and some software to show you awful graphics.

I remember reading this accident report now what feels like forever and a day ago.

Keep that thing fast in ice, Ted. And boot maintenance sounds like it’s not something to defer very long but was allowed on this 135 certificate if flight into known icing wasn’t expected.

I remember this accident starting a very big discussion of icing in general as the NTSB worked with USAF to fly the MU-2 behind the ice making tanker.

https://www.ntsb.gov/about/employme...ev_id=20001208X05205&ntsbno=SEA96MA043&akey=1

Keep it fast, it seems to do just fine. It’s just completely unforgiving of getting slow with that wing loading.

Looks like you’ll have fun with it.

 

[iamtheari]

Can I get a consensus on what is correct- Moo-two or Mew-two?

There is also Emm-You-Two. That sounds more like a fighter jet so it’s my choice, although that may give off a false impression that it’s an easy plane to fly.

But for this mission, meow-two seems best.

 

[overdrive148]

I’ll fly down to MKC. Top off the tanks, take off 30 minutes apart, and we go see @SCCutler in Dallas who will document our landing time. We go have some dinner and run back. Top em off again and we should have everything we need to run the #’s.

I will be a second opinion!

 

[sferguson524]

I’ll fly down to MKC. Top off the tanks, take off 30 minutes apart, and we go see @SCCutler in Dallas who will document our landing time. We go have some dinner and run back. Top em off again and we should have everything we need to run the #’s.

Make it a little longer distance.. VGT

 

[3393RP]

Ted, I imagine you are fully aware of the ADs concerning RPM limits during ground idle with a quartering tailwind.

Operation at a certain speed causes a reactionless mode resonance which can cause blade fatigue and separation.

I mention it because I found the literature describing the causes and effects of this phenomenon really interesting.

 

[ColoPilot]

Unfortunately with this plane, you'll only be able to rescue fast dogs - greyhounds, salukis, borzois, and vizsla. Pugs, chihuahuas, and anything toy sized will need to take a slower aircraft.

 

[Arbiter419]

I've been calling them "Moo-two"s for years, but I doubt that Mitsubishi as .



Definitely, I'd be curious as well. My expectation is that the MU-2 will be more efficient on fuel with a minimal time penalty, being a short body with -1s. On the other hand, your higher climb rate will get you to efficient altitudes faster and if you pulled back the power to have the same cruise speed (and being able to go higher since my ceiling is FL250) you might eek out some benefits.

The 300+ KT MU-2s will burn around 85 GPH to do it. I'm expecting to see around 260ish on 400 pph combined (so around 58 GPH) from what I've heard talking to others.

As you said, game on.

Another 50pph and you're in Pilatus land at the same speed think of all the dogs! A guy here has a long body MU-2, seems to like the GPU for starts. Very excited to see you guys make use of it!