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Question for those with J and K experience.


Will.iam

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I remember distinctly in my dad's 1977 201J model, if we were above about a 3 degree path down we were going to have to go around on our then 2000ft runway since the J glided so well.  I have now about 30 hours in my 252 K model and I can't help but wonder if I'm flying too much on the back side of L/D max or if the full flaps setting on the 252 was redesigned better than what was on the J because I can be higher than a 3 degree path and still have it slow down to where I can visibly see my sink rate increase. This is more pronounced when I slow from 80 kias to 75 kias that's with just me and 40 gallons of gas.  I practiced some simulated engine out landings and at 0 or 10 degrees of flaps it seemed to glide like I remember the J doing but the one time I rolled in full flaps I had to add power to keep from landing short of the runway.  Was just curious if it's due to my bad technique or if the turbo K just has more wing loading due to more weight in the aircraft than the J.  My dad's useful load was 950 I think where as my useful load is only 767.

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All Mooneys are slippery...

All 2k’ runways are short...

The only difference is going to be the Actual GLW of the ship... and the momentum that needs to be controlled...

See if @donkaye has any advice on landing differences between J and K on short runways...

Of course... Dad’s have a lot of skill...   :)

Best regards,

-a-

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With gear down and full flaps, at 75-80 KIAS, the plane is not slippery and will really sink.  It also uses far less runway.  It's the proper landing speed for short final, and the required speed for short field landings.

The angle of approach is related to the speed, but not exactly.  You could be flying a stabilized 3 degree approach at 100 KIAS in a clean configuration with the engine near idle and not be able to slow down and stop in time for a short field.  You could be flying the same 3 degree approach at 80 KIAS in a landing configuration and using more power and have no trouble at all.  Adjusting your angle of approach in different configurations at different speeds is a great exercise to really hone your piloting skills.  A good CFI can show you the differences.

I think you may be focusing on the wrong indicator for a go-around.  It should be your indicated airspeed, not your angle of approach.  At 75 KIAS the plane will drop nicely onto the runway with very little float.  At 90 KIAS you will float for most of those 2,000 feet.  Many pilots fly closer to 90 and have trouble as a result.  I myself would be concerned about a 2,000 foot runway and would consult the POH landing distance tables carefully.  That's not very long for a K model and you would have to nail your speed, if it's possible.

Also, your useful load should not change your landing performance.  Gross weight does that.  I believe all Ks are 2900lbs max gross.  Early Js had lower amounts.  If anything the lighter, earlier Mooneys should have better short field performance.  They have less mass to slow down and stop and aerodynamically are the same.  That was my experience going from a C model with speed mods to a K.  I expect it might be the same with a lighter J.  Just pointing out that your useful load number does not really have anything to do with landing distance.

Good luck getting used to the new ship, and good for you on spending some time figuring out how to master the landings.  It's a little different than other planes but very capable once you have the techniques down.

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As a new pilot in 1993 I got checked out in a almost new MSE at Denver’s front range airport. (Now KCFO) Back then they had a 2500’ 35/17 runway near the west edge of the airport. That runway was removed once DIA opened. At an elevation of 5500’ that was a pretty short runway.

That is the runway I was taught to land a Mooney on. Approach speed was everything. Most people get sloppy and fly 90 knot approaches. 
Mooneys are EASY to land if you use correct airspeeds. Until I had the approach numbers nailed every time I couldn’t rent that plane solo.

Thanks to that CFI my introduction to Mooneys was all about landing correctly.

 

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I have about 20 hours in a J and quite a bit in my 231. I flew the J first, then the K. I noticed the same thing you did, the J likes to float. If I was too fast or too high on the glideslope I was going to float a long way. Not so much with the K. It is a heavier aircraft, pull the throttle back to idle on the glideslope and it will fall. If I recall correctly the later J’s had the same GW as the K, but if you have one of the earlier models it is lighter by quite a bit.

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In the J, the slip is your friend if you are too high.  I remember several years ago I was getting some mountain flying instruction in my J.  We were returning into Longmont airport and I miscalculated the airport elevation in my head and started the pattern at 2000' AGL.  The instructor asked my intentions, to which I replied "I'm going to slip into a landing."  I don't know if he was scared or impressed, but he didn't say much on final and we crossed the threshold on speed and altitude no problem.  He also signed my logbook, so I guess I did okay.

I'm not recommending that, by the way...I was a lot cockier in my early flying career, and this led to some things I had to correct when I moved into the Ovation.  As noted above, approach speed is key, and with full flaps a Mooney will safely go a lot slower than many people feel comfortable with.  I think it's because we get used to the heavy feel of the controls when a Mooney is cruising, and when we slow it down the controls get mushy and it feels weird.  Learn to fly the Mooney slow and landing is not as much of a problem.

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Aren't the J and K the same airframe from the firewall aft (except for the trim system)? Don't they have the same wing and flaps? If flown at the proper speed for the landing weight, why would one float more than the other?
Skip

I’m guessing the extra weight and it’s extended nose results in a higher AOA required to keep the nose up, which generates more drag.
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4 hours ago, Jeff_S said:

In the J, the slip is your friend if you are too high.  I remember several years ago I was getting some mountain flying instruction in my J.  We were returning into Longmont airport and I miscalculated the airport elevation in my head and started the pattern at 2000' AGL.  The instructor asked my intentions, to which I replied "I'm going to slip into a landing."  I don't know if he was scared or impressed, but he didn't say much on final and we crossed the threshold on speed and altitude no problem.  He also signed my logbook, so I guess I did okay.

Lol...  ;)

4 hours ago, Jeff_S said:

I'm not recommending that, by the way...I was a lot cockier in my early flying career, and this led to some things I had to correct when I moved into the Ovation.  As noted above, approach speed is key, and with full flaps a Mooney will safely go a lot slower than many people feel comfortable with.  I think it's because we get used to the heavy feel of the controls when a Mooney is cruising, and when we slow it down the controls get mushy and it feels weird.  Learn to fly the Mooney slow and landing is not as much of a problem.

^^This.    When I first got my airplane I was getting used to approach speeds and it all felt kind of wrong.   The big difference in feel from normal/cruise speeds to approach was significant, but more than I thought it should be.   The airplane had a lot of deferred maintenance, and I guessed that the ASI was reading about 10kts fast, because if I did a short final approach at 70kts it didn't feel right, so I was using 80kts which worked quite well and I got used to flying it that way.   I later had the ASI overhauled and they said it read 15kts too high, oof.   I started flying at the recommended 70 kt IAS on short final, and my landings got worse, and to be honest I've never gotten back to being as good or consistent or having consistenty short rollouts to when I was flying probably 5kts "too slow" with the old ASI.

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4 hours ago, PT20J said:

Aren't the J and K the same airframe from the firewall aft (except for the trim system)? Don't they have the same wing and flaps? If flown at the proper speed for the landing weight, why would one float more than the other?

Skip

Well, aren't alot of Js at 2740 GW. The 231 is 2900 and later K's I believe go up to 3200 (the Encore?) on the same airframe. What I can tell you is how they feel. If you chop the throttle on short final in the J it wants to keep going. Push the nose over to get down to the runway and it wants to keep going, but faster. If you cut the throttle in a K it will fall, which I find a useful trait if I have to make a short approach or I start out too high.

A sidepoint, but the 231 does not like a rich mixture on final, it will burble. So one choice is to keep the mixture a pretty long distance out and manage airspeed pitch and throttle if needed. However, if you are pretty sure you are going around, another way to do it is cut the throttle way back and let the aircraft get behind the curve. Then power it up, its usually about 22 inches as I recall, maybe a little more, and you can then put in full mixture in preparation for your go around. Not a J issue, since they are NA they are not set up that rich, and they would not fall if you wanted them to.

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3 hours ago, ArtVandelay said:


I’m guessing the extra weight and it’s extended nose results in a higher AOA required to keep the nose up, which generates more drag.

Probably has something to do with it. We don't necessarily have to trim up to the stops like some of the turbo long bodies, but I am trimmed up when I land.

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47 minutes ago, jlunseth said:

A sidepoint, but the 231 does not like a rich mixture on final, it will burble. 

Mine does this too.  Mechanic says it's fine, it's set per book, and it won't shut off, and it never has.  That being said, I try not to go full rich until go-around, and leave the mixture at about an inch out during approach.  It takes practice and conditioning that you always go full prop and mixture before throttle, both for take-off and go-around.  I will usually go throttle about 1/4 in, then full rich, then throttle in.  At a minimum, this avoids uncomfortable looks from passengers when they hear the engine burble prior to takeoff.  I've often wondered if it's best practice or not, since if you forget mixture and go full throttle, you won't be making full power.  Interesting to hear others have the same experience.

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7 minutes ago, Zane Williams said:

Mine does this too.  Mechanic says it's fine, it's set per book, and it won't shut off, and it never has.  That being said, I try not to go full rich until go-around, and leave the mixture at about an inch out during approach.  It takes practice and conditioning that you always go full prop and mixture before throttle, both for take-off and go-around.  I will usually go throttle about 1/4 in, then full rich, then throttle in.  At a minimum, this avoids uncomfortable looks from passengers when they hear the engine burble prior to takeoff.  I've often wondered if it's best practice or not, since if you forget mixture and go full throttle, you won't be making full power.  Interesting to hear others have the same experience.

I do exactly the same with my tsio520 for exactly the same reasons.

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1 hour ago, Zane Williams said:

Mine does this too.  Mechanic says it's fine, it's set per book, and it won't shut off, and it never has.  That being said, I try not to go full rich until go-around, and leave the mixture at about an inch out during approach.  It takes practice and conditioning that you always go full prop and mixture before throttle, both for take-off and go-around.  I will usually go throttle about 1/4 in, then full rich, then throttle in.  At a minimum, this avoids uncomfortable looks from passengers when they hear the engine burble prior to takeoff.  I've often wondered if it's best practice or not, since if you forget mixture and go full throttle, you won't be making full power.  Interesting to hear others have the same experience.

The burbling doesn’t happen on takeoff in my aircraft. It does happen on final if the mixture is not leaned out. It doesn’t hurt anything, although I have had people on the ground tell me my engine is missing. It quits happening if I lean it out. No, it won’t quit on final because it is leaned out. If you lean it way out you do have to put the mixture in some on landing, or it will quit when the aircraft slows during the roll out. I do about the same as you when I have to go around or do a practice missed approach, I put in some power, then mixture, then full power.

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7 hours ago, ArtVandelay said:


I’m guessing the extra weight and it’s extended nose results in a higher AOA required to keep the nose up, which generates more drag.

 

3 hours ago, jlunseth said:

Well, aren't alot of Js at 2740 GW. The 231 is 2900 and later K's I believe go up to 3200 (the Encore?) on the same airframe. What I can tell you is how they feel. If you chop the throttle on short final in the J it wants to keep going. Push the nose over to get down to the runway and it wants to keep going, but faster. If you cut the throttle in a K it will fall, which I find a useful trait if I have to make a short approach or I start out too high.

 

3 hours ago, jlunseth said:

Probably has something to do with it. We don't necessarily have to trim up to the stops like some of the turbo long bodies, but I am trimmed up when I land.

Well, let's think about this. Both the M20K and the later M20Js have a max gross weight of 2900 lbs. I'm going to make comparisons at 2900 lbs, but comparing the two at any identical gross weights would yield similar results. At max gross weight the M20J has a CG range of 45 to 50.1 whereas for the M20K it is 43.5 to 49.3. So the K is a bit more "nose heavy." This was balanced out by requiring a bit more tail down force and changing the trim system from the bungees in all earlier models to a variable down spring. I believe that M20Ks trim with the elevator slightly trailing edge up whereas M20Js trim with the elevator slightly trailing edge down. 

Stall speeds at 2900 lbs with gear and flaps extended are close: 59 KIAS for the K and 58 KIAS for the J. 

The 2900 lb approach speeds listed  in the landing distance chart are 75 KIAS for the K and 78 KIAS for the J. 

Note that the stall speed for the J is one knot slower, but the approach speed is listed as 3 knots higher. That's actually pretty significant. I've always found 78 to be way too fast in a J. And, I think that's part of the problem -- a lot of people fly the Js too fast on approach, perhaps for the reasons that @Jeff_S and @EricJ mentioned. If in fact the K does sink more when the power is pulled back on approach it is either because it’s being flown slower (and thus deeper into the "backside" of the power curve) or perhaps the engine/prop combination has a bit more drag. 

Skip

 

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Some very complex replies to the op’s question. The short answer is that his premise (above 3 degrees equals go around for a 2000’ strip) is wrong.  Landing distance is a function of the energy carried to the threshold not glide slope angle. My SOP is steep and slow into short fields. I do not like the drag and drop method. I’ve used it but I am trying to be better.

Edited by Shadrach
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Thanks for all the feed back.  If I had the aviation knowledge I have now back then I'm sure I would have been more acute to what technique my dad was using and for all I know maybe my head height angle over the glare shield may have had an effect on my pitch picture since I'm much taller now.  It just seemed to surprise me how much more easy the K sinks when the power is pulled to idle. Nice to know other people have experienced this too so not so much anything unusual about my airplane just my expectations compared to what I knew and remembered of a J model. With dad having one of the first 1977 models I don't think his was as heavy as the later year models and always going for a flight around the patch, I'm sure we were usually on the light side of landing weight.   I have speedbrakes in my plane that my dad did not have but I don't need them for getting down that's for sure.  Also our runway has been extended to 2500ft now compared to then or it would be sporty with anything close to max landing weight. I still use all the runway to save on getting on my brakes too hard or possibly getting a flat spot on the tire if they lock up from the runway not being very smooth.  Most of the Baron twin guys are still wanting to extend it even more as they have seat pucker factor every time they fly out of there.

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That's a video of said short runway now 2500ft by our house. Has a nice big hill at the end of the north that is so helpful that most of us will land with up to a 10knot tailwind to take advantage of the hill slowing us down or take off the other way to use the hill to help accelerate us to flying speed.

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8 hours ago, jlunseth said:

The burbling doesn’t happen on takeoff in my aircraft. 

It doesn't happen on mine either unless I sit at idle and full rich, which quickly fouls a plug anyways.  I've just learned not to do that while I line up and wait.  I had developed a bad habit of always going full rich as I rolled onto the runway.  Now I only go full rich immediately before full throttle, problem solved.

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