2900 GW STC and landing speed

[fatlasercat]

I have just become a partner in an 89 M20J SE that has the 2900 GW increase STC. I am getting ready to "learn" to fly the plane and I came across something odd in the POH.

The main AFM says

"Airspeed on Final 71KIAS"

which is pretty much consistent with the common wisdom of 70 over the fence.

But the STC added a pretty lengthy AFM supplement. Most of that makes sense for the performance numbers, but it also say under Normal landing:

"Approach Airspeed 82KIAS"

That's a huge difference, and cannot really be explained by the moderate GW increase. Does it have to do something with the new ASI plate that comes with the STC?

Thanks.

[toto]

Not to be overly pedantic, but this isn't an STC.  It's the original type certificate.  But Mooney requires completion of a service bulletin to verify rudder balance tolerances and then adding the AFM supplement (and remarking the ASI if required).  

I have no idea about the approach speed - sounds like it's semantics between "final" and "approach" speeds.  Iirc there isn't a change of more than 2kts in the AFMS.

[gacoon]

If someone here has a POH for the later model that came stock from the factory it would be helpful to post that data here.  It might help clear this up, I agree that 11kt seems like a big difference??

[toto]

Where on earth are my manners?  Welcome to MS, @fatlasercat 

 

[gacoon]

8 minutes ago, gacoon said:

If someone here has a POH for the later model that came stock from the factory it would be helpful to post that data here.  It might help clear this up, I agree that 11kt seems like a big difference??

This is a follow up to my previous post.  I remembered that I had a copy of the service bulletin when I was considering doing this to my '90 J model.  Looking at the changes in Normal Procedures and Performance (landing charts) it seems that the higher number is indeed valid.  Varies by aircraft weight though.

Gross Weight Increase.pdf

[moosebreath]

I have a 97 J that came with a 2900 max gross.  I am at the beach just now but here are the numbers for stall at 0 bank angle from my manual at 2900 lbs.

Gear and flaps up ... 63 kts

Gear down flaps 15 deg ... 62 kts

Gear down flaps 33 deg ... 56 kts

 

1.3 times 63 is 82 so I guess that is where your “approach” number came from.  If you come over the threshold at 82 you had better be landing on the space shuttle runway!

Unless you have an emergency of some kind you will never be landing at 2900 lbs.  I try to operate under 2740 except on long cross country legs where carrying the extra fuel is advantageous.  The biggest problem at 2900 pounds is initial climb angle, not landing.

You can search the forum and find lots of opinions on flaps and landing speeds.  I find  75 kts full flaps, or a knot or two slower, over the fence perfectly fine at heavy weights which, as mentioned, is not often required.

My normal speed on short final is between 65 and 70 full flaps depending on my weight.  A knot or two slower than 1.3 times stall in the landing configuration has always worked well for me.

You will get many opinions ... my best advice is to find a nice long, wide, flat runway with no traffic and test different flap and speed combinations starting from 1.3 vso and see what you find comfortable.   The Space Shuttle might have landed shorter than a J will at 82 kts!

Have fun, Mooneys are great planes.

 

 

 

 

 

[gsxrpilot]

My M20K 252 has a 2900 max gross weight along with the same mid-body and wing as the 201. I do have the same 360 cu but distributed across 6 cylinders instead of 4. 

At the risk of blaspheme I'll say that my Mooney lands just fine at any speed between 65 and 90 knots. At the high number you might need 4000 ft of runway, but it will land just as smooth as butter.

I'll agree with @moosebreath that you should go find a longish runway, 5000 ft or longer, and just figure out what works. But you'll find that even 82 knots and no flaps over the fence is an easy landing speed in the Mooney. Just roll it on and don't let it bounce. 

A couple of years ago, back in the good old days before Covid, some 70ish Mooneys landed at Oshkosh on runways 36 L and R. Everything from M20C's to Acclaim Ultras and all came over the numbers at 90 knots. Easy.

 

[PT20J]

Here’s a page from a 2900 lb J POH.

[fatlasercat]

Thanks for all the replies. Will try all the different speeds to see how the plane behaves, but the solution seems to be low 70's.

[carusoam]

Welcome aboard FTL...

Will you be getting any Transition Training with your new 2U aircraft?

There are dozens more details to review that are a bit more coarse than the fine, yet important, detail you are asking about...

Getting a copy of the latest (or most proper) M20J POH can be done by calling your closest MSC...

I’m not a CFI... but I get a bit of un-ease while discussing landing speeds without mentioning a few other details... like temps and density altitudes... or weights...

Your  Mooney has proper data to go with it... Get a copy... get trained... don’t make a simple mistake...  

The first year with any new 2U plane can be very challenging... (Patrick’s lesson)

Best regards,

-a-

[tmo]

11 hours ago, moosebreath said:

The Space Shuttle might have landed shorter than a J will at 82 kts!

To be fair, it does have the chute ;-)