Flaps 15° for best rate of climb?

[ragedracer1977]

I was just browsing the 77 POH and notice in the climb table, they say the numbers are with flaps at 15°.  Just figured out my owners manual says the same.  I’ve never noticed this before.  Should I be climbing with flaps at TO setting all the way to top of climb?

ive always raised them shortly after takeoff.  I suppose I can try it myself and see if I get there faster or slower depending, just curious what your experience is.  

 

 

Edited June 20, 2018 by ragedracer1977

[carusoam]

Expect for performance, yes...

In real life, no...

Real life...

• has a flap speed that is pretty easy to exceed.
• exceeding a flap speed bends/cracks a minor spar.
• minor spars are expensive to replace...

 

• Air cooling is crummy at speeds less than 120 IAS...
• Crummy cooling leads to high CHTs...
• High CHTs lead to large expenses...

 

• T/O flaps add additional drag

So, unless you are climbing out over a mountain or trying to clear the local Class Bravo...

climb clean @120 and enjoy the ground covering speed with added fuel efficiency and decent air cooling...

 

PP thoughts only... the ancient Mooney texts were creative literary pieces of salesmen’s dreams...  part factual, but funky delivery... they didn’t think you would refer to them again after your first few flights... so it seems...

You get a few choices...

• V_x best rate of climb per distance
• Vy best rate of climb per time
• V_MS best rate of climb per dollar spent overall from an owner point of view...

And... that 77POH is great compared to anything available before it...!

I’m not a CFI...

Best regards,

-a-

[Skates97]

My problem is that maximum speed for flaps in my plane is 100 mph but the best speed for an enroute climb is 120 mph so I retract at 400 AGL and trim for 120 mph. 

[ragedracer1977]

22 minutes ago, Skates97 said:

My problem is that maximum speed for flaps in my plane is 100 mph but the best speed for an enroute climb is 120 mph so I retract at 400 AGL and trim for 120 mph. 

Where do you get the best enroute climb speed number?  I notice in all the C POH it states best speed is 100mph and under, all under flap speed, to address @carusoam post.  Also note that one of the images is from the 77 POH which also recommends flaps 15° for best climb.  

Typically I bring the flaps up around 400 agl and then climb around 105 IAS.  120 would have me in a very shallow climb and with all the mountains around, I want altitude as quickly as safely possible.  

Edited June 20, 2018 by ragedracer1977

[Skates97]

1 minute ago, ragedracer1977 said:

Where do you get the best enroute climb speed number?  I notice in all the C POH it states best speed is 100mph and under, all under flap speed, to address @carusoam post.  Also note that one of the images is from the 77 POH which also recommends flaps 15° for best climb.  

Typically I bring the flaps up around 400 agl and then climb around 105 IAS.  120 would have me in a very shallow climb and with all the mountains around, I want altitude as quickly as safely possible.  

It isn't in the speeds at the end of the manual. In my 1965 manual in the "Flight Procedures" section on page 19 it says:

"An enroute climb speed of 115-120 mph IAS is recommended for improved cooling and good visibility."

In the 1977 C POH which is much better it is in section 3, Normal Procedures on page 3-14:

"An enroute climb speed of 115-120 MPH (100-104 Knots) IAS is recommended for improved engine cooling and forward visibility."

I use 120 mph IAS whenever possible but there are times such as heading north out of my home field that I have a steeper climb at a slower speed. The need to go from 533' on the ground to 8,500'+ to feel comfortable going over the mountains north of San Bernardino in about 25 miles necessitates it.

[ragedracer1977]

9 minutes ago, Skates97 said:

It isn't in the speeds at the end of the manual. In my 1965 manual in the "Flight Procedures" section on page 19 it says:

"An enroute climb speed of 115-120 mph IAS is recommended for improved cooling and good visibility."

In the 1977 C POH which is much better it is in section 3, Normal Procedures on page 3-14:

"An enroute climb speed of 115-120 MPH (100-104 Knots) IAS is recommended for improved engine cooling and forward visibility."

I use 120 mph IAS whenever possible but there are times such as heading north out of my home field that I have a steeper climb at a slower speed. The need to go from 533' on the ground to 8,500'+ to feel comfortable going over the mountains north of San Bernardino in about 25 miles necessitates it.

Ah yes, I do remember seeing that, thanks.  Problem for me is all the IFR MEAs around are at least 9000’, and with a need to advise (AIM, so not regulatory, but...) ATC of an inability to climb at 500FPM, well...  at 120 IAS and 10000’, I’m climbing at 100fpm, maybe.  

Climbing out of KMYF last week, I was climbing at 90mph IAS and maintaining 405° on the CHT but making only about 300fpm after about 8000msl at near gross. So, you can see why I’m trying to wring any last bit of lift I can.  

[carusoam]

Brice,

I think you are on the right track... but you would have to generate your own numbers.... weight and temp are critical to each flight while climbing at max rate... at altitude...

 

I flew the C prior to having MS... often at 12.5k’ with four aboard...

I stowed gear, before going too fast...

Stowed Flaps And secured the fuel pump a 1k’ AGL...  this can become a memory challenge to wait any longer than that... done enough times... (pump gets forgotten, flaps get forgotten)

It leaves the opportunity to put it into your procedures... climb Vy to TOC... stow flaps, then accelerate...

I had a class B to get over... I would climb at 120 safely towards the side of the B, until clear of it by altitude... then change direction... continue climbing....

Solving this challenge comes with either a change in power or weight...  increasing the HP/wgt ratio works like magic...

See the threads regarding adding TNs to O360s....

Best regards,

-a-

[ragedracer1977]

16 minutes ago, carusoam said:

Brice,

I think you are on the right track... but you would have to generate your own numbers.... weight and temp are critical to each flight while climbing at max rate... at altitude...

 

I flew the C prior to having MS... often at 12.5k’ with four aboard...

I stowed gear, before going too fast...

Stowed Flaps And secured the fuel pump a 1k’ AGL...  this can become a memory challenge to wait any longer than that... done enough times... (pump gets forgotten, flaps get forgotten)

It leaves the opportunity to put it into your procedures... climb Vy to TOC... stow flaps, then accelerate...

I had a class B to get over... I would climb at 120 safely towards the side of the B, until clear of it by altitude... then change direction... continue climbing....

Solving this challenge comes with either a change in power or weight...  increasing the HP/wgt ratio works like magic...

See the threads regarding adding TNs to O360s....

Best regards,

-a-

I told @N201MKTurbo that I’m trying to wear this one out (at 250 hours over the last 12 months, I’m doing my best!) so I can convince my wife I need a 231 or a 252.  She’s trying to fly Arizona to Florida in the C over the 4th of July.  That alone might convince her a bird that flies a little higher and a little faster might be a good way to spend money.  Turbo normalizing the C is unlikely, but probably cheaper than upgrading to a 252, hahaha

[carusoam]

I went from crumbly C to a pretty nice O....

No convincing required.

Probably works for the 252 as well.

Best regards,

-a-

[ragedracer1977]

14 minutes ago, carusoam said:

I went from crumbly C to a pretty nice O....

No convincing required.

Probably works for the 252 as well.

Best regards,

-a-

My biggest Hangup is how nice my C is.  It’s gotta be in the top percent of nicest C models out there.  It has almost everything I want.  Except TN and a good autopilot. If it had even an AP, I’d really have to think hard about parting.  I thought this might be my forever plane, but the more I fly long distances, I’m not so sure.  My son is in the USMC and going motor T, so he’ll be in Missouri for a while.  Then my daughter really wants to go to Oregon State, so I can foresee some longer trips in the future.  

New Orleans is the farthest we’ve gone thus far, and we broke it up into 2 days.  Only 48 gallon capacity makes stops a little more frequent.  

[gsxrpilot]

1 hour ago, ragedracer1977 said:

My biggest Hangup is how nice my C is.  It’s gotta be in the top percent of nicest C models out there.  It has almost everything I want.  Except TN and a good autopilot. If it had even an AP, I’d really have to think hard about parting.  I thought this might be my forever plane, but the more I fly long distances, I’m not so sure.  My son is in the USMC and going motor T, so he’ll be in Missouri for a while.  Then my daughter really wants to go to Oregon State, so I can foresee some longer trips in the future.  

New Orleans is the farthest we’ve gone thus far, and we broke it up into 2 days.  Only 48 gallon capacity makes stops a little more frequent.  

I used to fly a very nice (panel, paint, interior, speed mods) and very fast (according to DMax) M20C... and sold it to get a 252. No matter how nice the C, the 252... Wow.

[Hank]

One thing Anthony didn't mention is how temperature affects climb. (Besides the fact that ATL's Bravo goes to 12,500 . . . ) Last weekend, my climb above 8000 msl was miserable, but it was 65° F there, when it should be below freezing. I was even holding around 95 mph, because if I let speed inch up to even 100 mph, climb went to mostly nothing.

[aggiepilot04]

According to the MAPA PPP, flap speed limitations only apply to full flaps...not T/O flaps.  My POH isn't very clear on that.

[Bob_Belville]

25 minutes ago, aggiepilot04 said:

According to the MAPA PPP, flap speed limitations only apply to full flaps...not T/O flaps.  My POH isn't very clear on that.

I will have to dig out the PPP manual, a very good resource, I do not recall ever seeing that distinction and my instinct is to ask "who says", or "says who?" 

[Bob - S50]

10 hours ago, ragedracer1977 said:

I was just browsing the 77 POH and notice in the climb table, they say the numbers are with flaps at 15°.  Just figured out my owners manual says the same.  I’ve never noticed this before.  Should I be climbing with flaps at TO setting all the way to top of climb?

ive always raised them shortly after takeoff.  I suppose I can try it myself and see if I get there faster or slower depending, just curious what your experience is.  

 

 

Ya, but that chart also says full rich mixture.  If you are still full rich at 18,000' the engine probably wouldn't even be running.

[Bob - S50]

9 hours ago, ragedracer1977 said:

Ah yes, I do remember seeing that, thanks.  Problem for me is all the IFR MEAs around are at least 9000’, and with a need to advise (AIM, so not regulatory, but...) ATC of an inability to climb at 500FPM, well...  at 120 IAS and 10000’, I’m climbing at 100fpm, maybe.  

Climbing out of KMYF last week, I was climbing at 90mph IAS and maintaining 405° on the CHT but making only about 300fpm after about 8000msl at near gross. So, you can see why I’m trying to wring any last bit of lift I can.  

Did you remember to lean during the climb?

[aggiepilot04]

10 minutes ago, Bob_Belville said:

I will have to dig out the PPP manual, a very good resource, I do not recall ever seeing that distinction and my instinct is to ask "who says", or "says who?" 

I'm not sure it's in the manual (I quickly flipped through and couldn't find it), but it was openly discussed in one of the sessions a few weeks ago in Fort Worth.  I also confirmed that I heard that correctly with the instructor that I flew with because that's the first time I'd heard it.  That being said, if this information is incorrect (or I misheard), I would like to be corrected here...that's why I posted.  Maybe someone that also attended the Fort Worth PPP can confirm or deny?

[Bob_Belville]

1 hour ago, aggiepilot04 said:

I'm not sure it's in the manual (I quickly flipped through and couldn't find it), but it was openly discussed in one of the sessions a few weeks ago in Fort Worth.  I also confirmed that I heard that correctly with the instructor that I flew with because that's the first time I'd heard it.  That being said, if this information is incorrect (or I misheard), I would like to be corrected here...that's why I posted.  Maybe someone that also attended the Fort Worth PPP can confirm or deny?

I'm with you. That makes sense and I have asked about whether the 100 mph flap limit applied to partial but I have never had anyone official or from the company confirm anything except flap speed is 100. 

[carusoam]

A few gray areas being discussed here....

1) Vfe flaps extended doesn’t adequately cover flaps kind of extended.... initial flight training in a C152... Vfe was not applied to the first notch of flaps....

2) Climb rates between fully loaded and lightly loaded aren’t covered very well...

3) Non-linear effects of OAT on lift and power... can really cause some surprises

4) Nice catch, Bob S50, on the full rich vs. blue box/white box/target EGT technique /observation... 

5) A POH that can cover all that... ranges from 300 pages to 1k pages when you include all the other important manuals addenda....

6) While collecting your personal climb data... expect the drag of the flaps, while deployed, is going to be expensive... Changing altitude is a function of power (mostly), less a function of lift (generally)...

Great cognitive exercise!

Best regards,

-a-

 

[N201MKTurbo]

One thing to think about is that when the flaps are all the way up they are being supported by the stop screws with no force on the actuator or linkage. As soon as you put them down even a little the force to support them is being carried by the actuator and linkage. There were incidences of cracks where the torque tube hinges mount to the airframe. It is suspected that it was caused by flap over speed.

I don't think you should operate above the white arc with the flaps down at all. Why would you need to anyway? Best rate of climb speed is in the white arc.

[ragedracer1977]

2 hours ago, Bob - S50 said:

Did you remember to lean during the climb?

Yes, I typically note my EGT at takeoff and lean periodically in the climb to maintain that egt

[aggiepilot04]

7 minutes ago, N201MKTurbo said:

One thing to think about is that when the flaps are all the way up they are being supported by the stop screws with no force on the actuator or linkage. As soon as you put them down even a little the force to support them is being carried by the actuator and linkage. There were incidences of cracks where the torque tube hinges mount to the airframe. It is suspected that it was caused by flap over speed.

I don't think you should operate above the white arc with the flaps down at all. Why would you need to anyway? Best rate of climb speed is in the white arc.

Agree that there's no reason to exceed Vfe in the climb with the flaps partially extended.  I was just pointing out that Vfe is for full flaps (at least, according to the PPP).

On the ILS with the gear down and takeoff flaps, I would exceed Vfe at 15" manifold pressure.  I'd prefer to keep in 15" manifold pressure for as long as possible so that the engine isn't excessively cold for the missed/go around.  Not to mention that I get "max forward speed" on the approach more often than not (being based at AUS).  That's the scenario where T/O flaps beyond Vfe would be helpful for me.

[N201MKTurbo]

26 minutes ago, aggiepilot04 said:

Agree that there's no reason to exceed Vfe in the climb with the flaps partially extended.  I was just pointing out that Vfe is for full flaps (at least, according to the PPP).

On the ILS with the gear down and takeoff flaps, I would exceed Vfe at 15" manifold pressure.  I'd prefer to keep in 15" manifold pressure for as long as possible so that the engine isn't excessively cold for the missed/go around.  Not to mention that I get "max forward speed" on the approach more often than not (being based at AUS).  That's the scenario where T/O flaps beyond Vfe would be helpful for me.

I don't put the flaps out until I have the runway in sight on approach. I realize that if it was an approach to minimums it could get kind of busy in the last few seconds in which case I would probably just land with no flaps. Its not that hard.

[kortopates]

That’s not true about flap limitation speeds applying to full flaps only. Only a few of later model Mooney’s including the later J’s have a higher limit speed for approach flaps. But when this applies the flaps have a detent position for this setting, it’s in the POH and it’s in the TCDS. Without those caveats it doesn’t apply.

 

Which is one reason my approaches are flown without flaps since I am the top of flap range and sometimes above.

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[Marauder]

My POH says VFo is 109 KIAS. That sounds like you can’t operate them above them either in the 15° or 33° position.

 

 

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