Maule M-4 glide polar

PCH · Post by **PCH** » Wed Apr 05, 2017 8:21 am

Has anyone worked out a glide polar for a Maule M-4?

Andy Young · Post by **Andy Young** » Wed Apr 05, 2017 10:35 pm

What's a glide polar?

ajak · Post by **ajak** » Thu Apr 06, 2017 9:20 am

Interesting- I was just looking at these, too. A glide polar, aka drag polar, is a set of graphs that you create by doing some fairly simple "test" flights, recording flight and engine parameters, and then reducing the data. It lets you determine the actual Glide Ratio, Best Glide Speed, Vx, Vy, Optimum Cruise and Max Endurance Speed for your plane in its current configuration.

Since there are so many different engine/wing/gear combinations that we fly, each person's Maule will likely have it's own unique power/drag profile, so one's drag polar would be pretty individualized.

Here's one resource I came across which shows generally how it's done and what you get out of it:

http://www.azcloudflyer.com/flight_test ... olar_3.pdf

I'm planning on trying to run one for my M-6 at some point in the near future. I've been kind of curious how the lengthened wing, VGs, and extended gear affect the "published" numbers in the AFM. I'll post some notes on how it goes.

PCH · Post by **PCH** » Thu Apr 06, 2017 4:21 pm

I ask because Foreflight has added Glide Adviser. This is a big help to determine your glide range if your plane magically becomes a glider. You do need the L/D for your airplane.

ajak is right in that our planes are so individualized as that each Maule will probably have a different polar. I'll report back as to what I find. I'll be curious as to what you find for your plane. Thank you for the above link.

Chris in Milwaukee · Post by **Chris in Milwaukee** » Thu Apr 06, 2017 4:31 pm

Not sure how the M-4 compares, but one fella on BCP, when asked the same, suggested 5:1 for my MX7.

ajak · Post by **ajak** » Fri Apr 07, 2017 4:04 pm

Funny, that new glide feature on Foreflight is what got me thinking about the drag polars, too.

Sounds like roughly 9:1 is what other Maule drivers have figured:

http://www.maulepilots.org/forums/viewtopic.php?t=1764

Chris in Milwaukee · Post by **Chris in Milwaukee** » Sat Apr 08, 2017 6:08 am

Well, now I have no idea. Reported numbers are all over the board. I guess I'll have to do my own tests.

pilot · Post by **pilot** » Sat Apr 08, 2017 7:55 am

Do you guys test glide with the engine at idle, shut off with a windmilling prop or do you slow down until the prop stops?

51598Rob · Post by **51598Rob** » Sat Apr 08, 2017 9:07 am

I think I won't let the far reaches of my longest possible glide path determine my landing point....just saying.

PCH · Post by **PCH** » Mon Apr 10, 2017 7:19 pm

Ajak-

Thank you for the link to the previous thread. I should have posted on that thread.

That said, I did a little test flying this weekend. My plane is a M-4 220c with 850s and no vortex generators installed. The testing was done with engine off, prop stopped and as feathered as possible.

Although my check list said 80 MPH was the best glide, I found that 70 MPH IAS provided both the best glide and lowest sink rate at both 0 and 20 degrees of flap. Best glide with 40 degrees of flap occurred at 60 MPH IAS.

Best glide L/D was 12 with 0 degrees of flap and 10.5 with 20 degrees of flap (both at 70 MPH IAS).

For my plane, if it turned into a glider, I would fly 70 MPH IAS, 0 flap till committed and plan on a L/D of 10 (and hope the engine hadn't quit in a downdraft).

I would be interested in seeing other people's findings.

xcflyn · Post by **xcflyn** » Wed May 03, 2017 4:15 pm

Mine glides like a watermelon.
Which in technical terms equals 1pt. better than a helicopter.
Actually being a glider pilot in a prior life I would be surprised if it was over a 7:1 , in the 80's hanggliders were about a 8:1 and my M4 does not feel that slippery, thou I have powered off and climbed in some nice strong southwest thermals-but that's a different thread.

Duane · Post by **Duane** » Wed May 03, 2017 5:19 pm

Xcflyn.. nice to meet another glider guider

xcflyn · Post by **xcflyn** » Thu May 04, 2017 8:09 pm

God I miss it . they shut the glider port here down a few years ago. But I am going to fly hanggliders again this summer. I had a double discectomy triple fusion in my lower C's , so my neck is finally healing enough to fly prone again.
Gliders and tailwheels - the two best forms of flight !

PCH · Post by **PCH** » Sun May 07, 2017 12:14 pm

Duane- I too am a glider pilot. Best of all, my M-4 has a tow hook. Nothing makes friends faster in the glider community than a towhook.

xcflyn- I have to agree with your gliders and tailwheels comment.