2 questions

[midlifeflyer]

Only suggestion I can make on the glide ratio issue without a POH chart is to take a similar model as a baseline and see if it is confirmed or substantially different in yours. Personally, I would have no problem saying that on a checkride. 

I try to keep in mind that the ratio, even as published in a POH, is at best a ballpark. It's based on a clean airframe (in more ways than one), no wind, using perfect pilot technique nailing the best glide speed for your weight. My typical flight involves none of those.

You'll do great. Remember, the commercial certificate is mostly about not scaring the passengers.  Just leave the hip flask home.

[Bob E]

10 hours ago, eman1200 said:

Yikes. Although I don’t have a vacuum step, mine is bolted on. Doesn’t retract.

Ha.  Reading comprehension -- should have noticed that.  My guess is that if the non-retractable step is welded to the frame, a gear-up would likely bend the frame.

[Jerry 5TJ]

A glide ratio question, or two —

Best glide is found at or very near the peak of the L/D curve.  The L/D curve is “more forgiving” for an airspeed slightly below the best than for speeds above best glide.  

The airspeed for minimum sink rate is below that for best glide, as shown in this graph from the venerable “Aerodynamics for Naval Aviators” 

 

This implies if the engine fails, and the pilot hasn’t yet figured out where to head for the landing, to immediately establish an airspeed at or slightly below best glide is good practice. 

The same handbook states that L/D is unaffected by altitude—the same IAS applies but the TAS and sink rate are correspondingly higher resulting in the same glide ratio.  

A puzzle is that my plane, a PA46 with a full-feathering propeller, has a published glide ratio that varies with altitude: Down low it is 15:1 while above 20,000 it rises to around 20:1.   What causes that improved glide ratio?  

And would the same effect apply to a high-flying Acclaim which might expect 15:1 glide up at FL240 and 12:1 at sea level? 

[Bob - S50]

I'll add a couple comments about minimum sink best glide and give a reference.

Minimum sink, which gives you maximum time before you hit the ground is Vy.  Yes the same Vy as best climb.  So if you want as much time as possible to prepare for landing then that's the best speed.

Best glide is a little bit faster than Vy.  So if you want to glide as far as you can, go a little faster than Vy.  How much?  Don't know, but not much.  The POH for my J lists Vy at max gross as 88 KIAS at SL and best glide as 91 KIAS.

Here's an article for you to read if you like:

See How It Flies - John Denker

[carusoam]

5 hours ago, Bob E said:

Ha.  Reading comprehension -- should have noticed that.  My guess is that if the non-retractable step is welded to the frame, a gear-up would likely bend the frame.

Expect that Mooneys are designed to handle GU landings with aplomb....

There won’t be a bent airframe, because somebody over-designed a step...

 

When forced to land GU... do it.  Ignore the step.

 

See if @takair is around to lend some insight regarding the strength of the fixed step...

Best regards,

-a-

[takair]

6 hours ago, carusoam said:

Expect that Mooneys are designed to handle GU landings with aplomb....

There won’t be a bent airframe, because somebody over-designed a step...

 

When forced to land GU... do it.  Ignore the step.

 

See if @takair is around to lend some insight regarding the strength of the fixed step...

Best regards,

-a-

I can’t speak to the specific strength, but a potential customer recently provided me pictures to discuss possible retrofit to a retractable step.  The fixed step seems to have a formed sheet steel skin adapter, such that the skin bears a significant portion of the load.  The rest is transferred to the bulkhead via a bolt. The retractable step has a significant structural doubler on the bulkhead, the fixed step does not.  My guess is that the fixed step is not quite as strong as the retractable structure, but it may also cause less overall damage in a gear up should the step catch on something.  I suspect that a gear up landing in grass or in the rough could cause damage to the skin and bulkhead.  I also think a well executed gear up on pavement may limit this structural damage.  Perhaps one of our salvage or rebuilding experts like Jerry or Alan May have seen the actual results tot he airframe.