WOT Descents..Who's doing them?

[BigTex]

My C has a Vne of 189 mph so these models all have different V Speeds.  We need to be careful generalizing that just because you use a given speed and/or technique for one model, the works for all.

[Lood]

I never reduce rpm for the descend. I normally cruise between FL065 - FL095, ROP, WOT (always) and 2500 rpm. For almost all descends I push the nose over to establish a descend at around 400ft/min, as that's where my pax are most comfortable wrt their ears.

The MP is normally somewhere around 21" and during the descend, I just keep it at that. Every 1000' or so, I will pull back a tad on the throttle to keep the MP at 21" and this has always kept me well in the green, without any major drops in CHT's.

Where quicker descends are required, I just reduce power to around 19" and that's it. Our Mooney's are indeed slippery, but I've never had trouble getting down with the air speed running away. Come back on the power to around 17" and the descend rate becomes substantial, while keeping the speed in check.

[danb35]

My biggest worry if I go all the way through landing with low RPMs and leaned is what if I need to make that rare go-around.

My thoughts on this, given my descent profile (again, I typically leave mixture and prop at their cruise settings until shutdown), are that even if I forget to push prop and mixture forward, and just hit the throttle, I will still climb out--after all, I should be at a pretty close approximation of cruise power.  It won't be the best climb-out, but it will still get me climbing while I take care of resetting prop, mixture, flaps, gear, etc.

 

The process, though (which I've practiced) is mixture, prop, throttle.  Takes a second or so.

[Hank]

My C is green to 175 mph, then yellow to Vne at 200 mph. I ease throttle back to stay green as it is often bumpy descending in the yellow. The higher speed makes up for the climb, and helps reduce block time.

[1964-M20E]

I never reduce rpm for the descend. I normally cruise between FL065 - FL095, ROP, WOT (always) and 2500 rpm. For almost all descends I push the nose over to establish a descend at around 400ft/min, as that's where my pax are most comfortable wrt their ears.

The MP is normally somewhere around 21" and during the descend, I just keep it at that. Every 1000' or so, I will pull back a tad on the throttle to keep the MP at 21" and this has always kept me well in the green, without any major drops in CHT's.

Where quicker descends are required, I just reduce power to around 19" and that's it. Our Mooney's are indeed slippery, but I've never had trouble getting down with the air speed running away. Come back on the power to around 17" and the descend rate becomes substantial, while keeping the speed in check.

My descents are similar I just let the MP climb to 25" then reduce throttle to maintain 25"MP and maintain 2500RPM.  I leave the mixture where I was in cruise.  I can generally get up to about 700fpm+/- decent and stay low in the yellow arc.  If ATC advises me to descend at pilots discretion and I'm not ready to descend I generally set up for about 300 to 400FPM to stay in the cool air longer.  If I need to descend faster I'll maintain 21"MP and setup for 800 to 1000FPM and maybe even back off to 18"MP if necessary.  I do what I need to do to satisfy the distance, altitude airspeed equation to get me down to the altitude I need to be when I need to be there.

[stevesm20b]

My C is green to 175 mph, then yellow to Vne at 200 mph. I ease throttle back to stay green as it is often bumpy descending in the yellow. The higher speed makes up for the climb, and helps reduce block time.

What did they do to the 1970 model C to increase the green arc from 150mph to 175mph, and the Vne from 189mph to 200mph?

[Hank]

My Owners Manual is in the Download section--1970 M20-C electric. Gross weight is 2575; 52 gallons of fuel; full length rudder; PC system; electric gear and flaps; O-360-A1D with Marvel Schleber updraft carb.

Most if not all were implemented prior to 1969, but I can't tell you when exactly. My back windows are rectangular, not rounded triangles, too. No shotgun panel, either--from the factory. It's in standard 6-pack configuration, on a slant.

If you can spot the changes, Steve, please let us all know. I have no idea.

 

Here's the page from my Owner's Manual now that I'm no longer on the phone. I can't say why, this just supports me when I say that.

 

 

[pinerunner]

My Owners Manual is in the Download section--1970 M20-C electric. Gross weight is 2575; 52 gallons of fuel; full length rudder; PC system; electric gear and flaps; O-360-A1D with Marvel Schleber updraft carb.

Most if not all were implemented prior to 1969, but I can't tell you when exactly. My back windows are rectangular, not rounded triangles, too. No shotgun panel, either--from the factory. It's in standard 6-pack configuration, on a slant.

If you can spot the changes, Steve, please let us all know. I have no idea.

 

Here's the page from my Owner's Manual now that I'm no longer on the phone. I can't say why, this just supports me when I say that.

I'm jealous,

 

My 64 M20E has all the speed restrictions. I especially my max flap extended speed no higher than 100 mph. It's very easy to exceed that if I get distracted. Are your flaps beefier than the older ones?

 

Dave

[Shadrach]

I beleive all of the changes you guys are discussing were "paper" changes. ie. no changes to the air frame structure from 64 to 70.  Don't quote me though...

[jlunseth]

I push the nose over and pull the MP back about inch, trim for 500' per minute descent.  I adjust the throttle during the descent to maintain a relatively constant MP.  I will descend all the way from the flight levels to the airport that way.  The reason for taking out an inch of MP is that ram air effect will increase MP by that much.  I am generally running ROP at cruise and I just leave the cruise mixture setting where it was.  If it gets bumpy I will do something else, but generally I have several thousand feet before reaching the cloud layer.

[Jeff_S]

For me it all depends on the likelihood of bumpy air as you descend...which in the summertime in the South is VERY likely! So I generally start to dial back the MP and reduce RPM to maintain a comfortable IAS, whatever that happens to be for the conditions. But I like to be at 20"/2400RPM when I level out because that starts my landing routine. And as others have said, I leave the mixture where it was at cruise LOP unless I am going to be in a sort of extended holding situation or otherwise need to manage temps better.

[Hank]

I beleive all of the changes you guys are discussing were "paper" changes. ie. no changes to the air frame structure from 64 to 70.  Don't quote me though...

 

I thought there was some change to the rear spar that the flaps are mounted to?

 

But I understand Dave's frustration, that's just how I feel reading about J's dropping gear at my own cruise speed in lieu of speedbrakes, or to initiate descents. I use my own gear to start descending when I'm 1½ dots high on the glideslope, as it takes a little while to have a noticeable effect.

[pinerunner]

I beleive all of the changes you guys are discussing were "paper" changes. ie. no changes to the air frame structure from 64 to 70.  Don't quote me though...

Well Hank mentions full length rudder ( like the F and J models is what I'm assuming). That could be a pretty significant change, maybe stronger, maybe more stable. My 64 E yaws a bit when its rough at speed.  

[Seth]

Not me - the Missile will go down or slow down. No speed brakes. I'll go past the never exceed speed easily at full power in a decent.

So no WOT decents for me. Cruise power decents sometimes, but not WOT as I get lower.

-Seth

[Shadrach]

Not me - the Missile will go down or slow down. No speed brakes. I'll go past the never exceed speed easily at full power in a decent.

So not WOT decents for me. Cruise power decents sometimes, but not WOT as I get lower.

-Seth

Even at 500FPM?  I can easily exceed redline as well...if I try, but at 500FPM I think I only see about a 10 to 15% increase in IAS.Does the Rocket cruise that close to the redline?  Even at altitude?

[Shadrach]

Well Hank mentions full length rudder ( like the F and J models is what I'm assuming). That could be a pretty significant change, maybe stronger, maybe more stable. My 64 E yaws a bit when its rough at speed.

I thought everything after 67 got the big rudder... I cannot imagine that that has anything to do with gear speed, flap speed or even VNE for that matter... The big rudder helps just wher you think it would, at approach speeds and at high AOA...at 170kts, I'm sure the shorty provides plenty of authority.

[jetdriven]

the yellow are is the source of much rumor, fear, uncertain, and doubt.  OMG, the wings might fly off at any second......

[kmyfm20s]

the yellow are is the source of much rumor, fear, uncertain, and doubt.  OMG, the wings might fly off at any second......

For our aircraft I would agree in others there is a legitamate argument for some tails would fall off. There is an interesting thread on the V-tails on Beechtalk and they seem to be very thoughtful of design limits. Im not a V-tail hater either I just have 2 strikes against me for that plane, I'm a Doc and I'm to tall to sit on top of that wing spar.

[Shadrach]

I love v-tails. I count the V35B as one of the best performing and best looking GA passenger planes. However, it's no secret the Beech had issues with the early design and that it was fragile in the hands of MDs ;-). They did beef up the structure over the years. Metal Mooneys (as you stated) did not suffer from this. The wing on a 64 C model is essentially the same as the wing on an Acclaim save for the root fairing and tips. The gear was beefed up for higher MGW. Some of the numbers on the early birds are down right silly in comparison. Even my F cruises well into the yellow at lower altitudes in the winter.

[kmyfm20s]

I love v-tails. I count the V35B as one of the best performing and best looking GA passenger planes. However, it's no secret the Beech had issues with the early design and that it was fragile in the hands of MDs ;-). They did beef up the structure over the years. Metal Mooneys (as you stated) did not suffer from this. The wing on a 64 C model is essentially the same as the wing on an Acclaim save for the root fairing and tips. The gear was beefed up for higher MGW. Some of the numbers on the early birds are down right silly in comparison. Even my F cruises well into the yellow at lower altitudes in the winter.

I agree!

[Shadrach]

Well, the hydraulic versus electric flaps are an obvious change that might be relevant to this discussion.

Jim

Why would the addition of a worm gear and an electric motor have an effect on V speeds?

[pinerunner]

Pinerunner in the post prior to yours brought up the older models' 100 MPH Vfe. That was what I was referring to and assumed you were referring to.

Jim

I wouldn't assume the hand-pumped hydraulic would be weaker than electric. On my older E model the actual flaps don't look like they're mounted in a very rugged way. They basicly swing on a bunch of bolts with locknuts and an axle through the head of each bolt. The flap seems to kind of fly free with the bolts holding it in its center of lift and able to swing back, rotating around the axles. The affair is actuated inboard and i wonder about the torque on the whole thing and the stresses on the outboard "bolt". It doesn't look very rugged to me  compared to the Cessna "paralift" flap but maybe the stresses are balanced just right and its really much better than it looks. Anyway I take the 100 MIAS Vfe very seriously and find it way too easy to exceed. I wonder if the newer Mooneys have that beefed up somehow.

[fantom]

.....yes later models did get a rear spar doubler that beefs up the flap mounting quite a bit.

 

....and I'm glad mine has the spar doubler for reasons I won't get into.

[jetdriven]

Hey fantom did u try the 190 knot downwind entry yet?

[fantom]

Hey fantom did u try the 190 knot downwind entry yet?

Not in a Mooney Does 150 knots until 3 miles out count for something? You getting your bird painted out here for Christmas?