AOA in a Mooney

[Buster1]

Does anyone have AOA in their Mooney?  Do you know if you can add it later?

As a military pilot, we fly and land by AOA...I think it is not only a valuable tool, but almost a requirement for safety.

Seen some on line where they have to put small holes in the wings, and I've seen a few other types as well.  Can these be added, are they only experimental, or are they (STC'd is that the right word?) for a Mooney.

Thanks!

[jrjaks]

Quote: Buster1

Does anyone have AOA in their Mooney?  Do you know if you can add it later?

As a military pilot, we fly and land by AOA...I think it is not only a valuable tool, but almost a requirement for safety.

Seen some on line where they have to put small holes in the wings, and I've seen a few other types as well.  Can these be added, are they only experimental, or are they (STC'd is that the right word?) for a Mooney.

Thanks!

[Carl S]

My wife is waiting for me in the car so I don't have time to reason this out, but what about a 337 form for a Dynon?  It would not be a promary flight instrument but they do have an AoA option. Cheap in a relative sense also.

 

 

[M016576]

Hi Buster-

     It would be nice to have AOA in a mooney, but I don't see it as safety of flight equipment (neither do the pro's from Kerrville, either, apparently).  I understand why we need it in the Hornet, and I imagine that your viper is similar: thrust curves + relatively large changes in gross weight due to fuel burn + precision glideslope control + attitude at touchdown = AOA approaches.  In the mooney, airspeed does the trick well enough (it's only a few KTS shift between full weight and empty).  I think the lack of an AOA gauge is primarly due to private pilot training, where advanced aerodynamics isn't really broached as a subject.  Regardless, the only two times I would want to see AOA in the mooney are A) on approach, on the waveoff (nice to know exactly what the best alpha for a flyaway is... especially at high altitude in a 200hp single!).  You'll find that the Mooney has plenty of buffet/response to let you know as you approach the onset of a stall or approach turn stall.  The one thing I really don't like about it is that she tends to exhibit a pretty harsh wing drop (maybe that's just mine, though...)... I wouldn't want to experience that during the approach turn.

     Are you in the guard or AF?  I recently purchased a 1980 M20J for trips from my duty station to my parents home up in Idaho: it's nice to have the flexability to land at any FBO that'll take me, regardless of contract fuel... and it beats driving! 

                                                               -Job

[Buster1]

Thanks guys, guess it may not be worth it huh?

Job, I am Active Duty, flying Vipers at Hill Air Patch just north of Salt Lake City, just south of Ogden Regional where my rental Cessna parks!  Moving to Vegas in 2 months to begin a new adventure there, and hopefully purchase a 231!

Thanks for the help guys!

[GeorgePerry]

With over 2000+ hours in civil aircraft and 3000+ in TACAIR platforms, making an Apples to Apples comparison between TACAIR and light civil aircraft is impossilbe.  I'd be like comparing a dump truck to a modern ferarri.  Yep they both have a steering wheel, but that's where the similarities end.  Miltary flying and GA (Mooney) flying are completely different.  To try to apply military flying techniques to a small GA aircraft just doesn't work...at least not well. 

On a slight tangent since we're talking Civilain / Military comparisions...[Present complany excluded]...Lots of Military Fighter Jocks don't give small airplanes the respect they deserve.  After I graduated from Embry Ridde I worked as a CFII and chief flight instructor at a flight school just down the road from a Marine Air base.  Lots of Marine pilots would stop by to get checked out in our 172's so they could fly their wives or girlfriends or get ready for their Southwest Checkrides.  These guys might have been great sticks in the harrier or F-18, but they were down right dangerous in a small plane.  My point here is what works with a fighter, doesn't work well with GA aircraft.

AOA isn't important for GA aircraft - Airspeed is.  The only time AOA would be important in a GA aircraft is if there's a significant load (G's) on the airframe.

Also...LEX (leading edge extension) equipped aircraft don't stall like straight winged GA planes do.  A GA aircraft has a very specific stall speed (1.0 G level flight) with an immediate loss of lift after the boundry layer detaches from the upper airfoil surface.  Military TACAIR jets like the hornet and viper have a LEX that allows controlled flight well beyond alpha ranges associated with the traditional "stall".  Not to mention that Vortex lift generated by the LEX and Laminar flow lift are two different aerodynamic creatures.  All of this and that doesn't even begin to factor in the WOPPER super computers that modern fighters have.  They instantly calculate every known flight parameter,  program in the required flight control surface input and artificially smooth out rough handed pilots with software tools like beta dot feedback and rooling surface interconnect.

I'm not writing this to bust anyone's bubble as much as I am to convey to the non-military pilots who read this board that flying a GA aircraft well is MUCH HARDER than flying in a modern fighter.  Modern TACAIR planes are designed to be easy since flying isn't the reasons they exsist.  TACAIR platforms sole purpose in life is to act as a weapons delivery platform.  Anyone, and I mean anyone could be tought to just "fly" a modern fighter.  The same can not be said for GA aircraft...They actually require some stick and rudder skills.

[mjc]

As far as I am aware, it's the serious backcountry pilots who love AOA indicators. I'm told that an AOA indicator (actually a lift reserve indicator, I think) gives them the capability to bring the airplane in at absolute minimum speed regardless of density altitude for really short landings and climb at the highest possible angle after takeoff. Aside from that use case, I agree with the others that using airspeed to judge lift reserve is probably fine. And yes, while a Mooney works just fine in the backcountry, it isn't really the ideal airplane to get in and out of the shortest strips. An AOA indicator is probably less useful than, say, VGs or gap seals.

[M016576]

Mr. Perry-

         I respect your opinion and spent quite a while thinking about your statements regarding the difference between flying a light civil vs. a modern fighter.  I cannot speak for any modern jets other than the T-2C Buckeye (not so modern), T-45C Goshawk and the F/A-18A-F.  On the "civilian" side, I have flown a C152, C172, Piper Archer II, Piper super cub, Mooney M20J and Pilatus PC-12.  I have just short of 3000 total hours.

I like to think of the comparison more as the difference between an Audi and a Formula 1 car.  A capable driver can sucessfully navigate either vehicle, but those used to flying an Audi will struggle to maximize the performance of a Formula 1 car.  I disagree that applying military flying techniques to a small GA aircraft won't work: I find they not only work well, but emphasize generally safer principles in both preflight planning and enroute procedures.  There are a few exceptions to this, particularly in regards to engaged manuevering within a MOA, which is a dangerous prospect.

I initially nodded as I read your summery of why it was easier to fly a fighter than a mooney (light civil), but after giving it some thought, I now disagree: here's why....

 What you say about the LEX is true.  Also, our flight control computers in both the Hornet and Super Hornet are amazing (they allow for controlled flight well into a developed stall, of course the danger of a tailslide+motor snuffing ensues in these situations). Both the Hornet and Super hornet also auto trim to 1 G flight.  When flying at high alpha, if a lateral stick input is sensed, the flight control computers will attempt to give the appropriate response, but using all 12 flight control surfaces.  Truely a sight to be seen from the cockpit (lots of twitching control surfaces)!  I believe this is why you said it is "easier to fly a tacair aircraft."

Here is why I think it is harder:

A)  The speed.  You can put a fighter pilot in a cessna and he won't have many problems "keeping up."  When I transitioned from the T-45C (a pretty fast jet!) to the FA-18E, I oversped the gear in my first sim (most of my friends did the same, as do many students now).  Afterburners/large motors move you along at quite a clip, and you are right: you can train people to deal with the speed (once they get used to it), but there are PLENTY that don't make it through flight school... ask two of my five roommates from Meridian.... 

  The systems.  you aptly described the beauty of the flight control computers.  Did you know the FA-18 does not have a VOR or ILS?  In fact, the only precision approach we can shoot at a civilian airfield is a PAR.  The "moving map" is nice, but our TACAN systems aren't the most reliable, and while our INS/GPS system is nice, it is not tight enough to be certified by the FAA, and a far cry from a WAAS system.  Also, our autopilot is fairly basic by modern standards, having only a couple to course feature, baralt hold or flight path attitude hold setup.  It will not shoot an approach for you at a normal field (the carrier is a bit different, I can get into that later)

C)  The boat.  Landing on the carrier is the hardest thing I've ever done in my life.  Day gets to be fun.  Night never does.  It's all hand flown*.  (I'm asterisking this because senior pilots, once they have proven their ability to land on the boat, may couple to the ACLS at night or in case III scenarios... over the course of 5 deployments, I have done this once [it was scary], and I have seen it done only a handfull of times).

D)  The mission.  Two people flying in excess of 500kts (initially), at alphas in excess of 35 degrees both trying to kill each other.  It's hard and dangerous, even in training.  Low level attacks are practiced at 100-200 feet and 540kts ground speed, while our velocity vector helps us avoid hitting the ground, it is by no means an easy task, and it is hand flown.

In my mooney, I take off, level off, couple my autopilot to the GPS, then plan an enroute descent so as not to overspeed or cold shock the aircraft.  Then I land.  The landing part is hard for me, I'm not used to flaring and a mooney is VERY sensative to both ground effect and flaring.  However, after a few hours with a CFI that had experience in a mooney, I figured it out.  Honestly, my M20J is far more capable an IFR platform than the hornet: it's got a 430W (waas approaches), and ILS, two NAV radios (hornet only has a single TACAN), XM weather (awesome!) and a century 41 autopilot that will shoot an entire approach for me!  Heck, the Garmin displays the whole appoach!  In the hornet, we have to fly it all manually: we don't have the GPS database onboard (not enough memory for it, we use our waypoints for tactical purposes). 

Other difficulties, like I mentioned: 

A) the Mooney (or my mooney, at least) has a bit of roll-off when it stalls.  

and

the single engine mentality- I had to get back into the "if I lose my motor, where am I going to glide to" mind set. 

 

All in all, I believe that flying a military jet is the same as a general aviation jet or turboprop if all you are doing is going from point A to point B in VMC conditions AND you are used to flying at 250kts below 10000' and much faster at high altitude.  However, when you factor in the other missions we are required to perform, I believe it is more difficult to fly the military jet.

 

Just my 2 cents! 

[carusoam]

So, does the stall warning indicate AOA in any way, more or less?

Excellent technical discussion above.  I was interested in AOA so as I near the runway, I can flare with a known margin of safety.  Realistically airspeed is used for this.  However, my eyes are outside the cockpit for this part of the flight.  I don't think I could watch either the airspeed or AOA at that point. 

The stall horn warning however occurs audibly prior to critical AOA.  horn silent AOA below critical, horn blairing AOA near or at impending critical AOA.

Please note: I offer to trade seat time in an M20R for comparisons in an F/A-18A-F (or similar).

[Immelman]

I haven't flown with an AOA indicator, and I'm a civilian pilot.

But from what I've seen, I think it could be a very useful tool. I disagree with the generalization that you can look at AoA in a light GA airplane by airspeed alone -- for example while landing. Hear me out here: Any mooney pilot will tell you that speed control is critical on final to get a good, safe landing. I would argue that its not speed, its AoA... and that varies, substantially in my opinion, depending on the landing configuration (flap setting) you choose and gross weight. I can tell by 'feel' now that solo I can take 5mph off of my final approach speed comfortable for operaitons at max gross, and still carry more float into the landing flare than is desirable. Add in variations in flap selection (example, due to crosswind) and it gets even more interesting. How much margin do you have on a partial flap landing at max gross flying the same speed as you normally do solo... perhaps not as much. as you think! I think an AoA indicator would therefore be quite useful.

Although I have not seen such a mod, I would think an interesting modification (is it possible aerodynamtically?) would be to replace the traditional stall warning "switch" common in mooneys with something that measures AoA (not merely a SPST switch) and feeds that into the cockpit. The instrument could still issue a stall warning at a pre-determined AoA. I think such a mod would be interesting because it would not require any airframe modifications, just an indicator and replacement of the sensor switch.

[Buster1]

Commander, Job, and all,

Great discussion overall, but way too many Navy guys in here talking;-)  For an Air Force perspective here goes.

First off, aural stall warning is great, but AOA in the Viper (F-16) is done via lights on the glareshield (very easy to see in the landing picture) and in the HUD...which you look thru to see the rwy.  So it's an easy crosscheck.  Aurally would be tough to do in my opinion as there are so many possible degrees of AOA that it needs to be presented somewhat visually.

Commander, while I agree with you, I disagree too.  I have to say, I carry a ton of respect for any airplane, and was actually pretty nervous getting checked out a few months ago in the Cessna 172.  It has been 10+ years since I had last flown a GA plane.  I have 300+ GA hours, commercial, multi, instm, glider...all pre-air force and mostly on my own dime.  I too have seen a few military guys get into trouble in GA aircraft.

I also disagree with you.  I have personally sent students "packing" in the Mach capable T-38.  Some could handle the complexity and speed, some couldn't.  I believe both Mil and GA flying each bear their own eases and difficulties.  Handling bad wx in a Viper is much easier that in a light single, I just power thru it and climb as high as req'd.  Can't do that in a Mooney.  Patterns and landings in a Cessna...much easier than in a Viper.  It's give and take.

Job, the Viper sounds very similar to the Hornet for landings and approaches (but we flare!).  Archaic Tacan, hand flown ILS (just one in the jet), 2 radios, and no moving maps or coupling.  I however am used to the single engine mentality and will trade airspeed for altitude if the engine just looks at me funny.   We also ALWAYS know our prox to every suitable airfield at all times.

Lastly, Carusoam, the AOA does not indicate a stall, or vice versa.  AOA simply indicates the relative wind over the wing...which gives you a performance factor to use.  Stall warning just tells you that a stall is occuring, and in fighters, a wing stall can occur and almost any speed or AOA.  I can stall a T-38 at 300KIAS, 90 degrees of bank with just 4 Gs.  At 45 degrees of back, it's totally different.  The Viper wing WONT stall as the computers constantly adjust the Leading edge slats and Flaperons (like in Job's Hornet) to keep her flying.  (It's actually tough to land as the Viper just won't settle to the rwy when you're aerobraking).  Stall warning and AOA are different, but in light GA planes stall warning is the simple option, and it works, and AOA in light planes is relatively the same thruout the mission.

Nice chat guys.

Nate

[jrjaks]

While it would be an "interesting" gadget to have, an AOA just isn't necessary for Mooneys, (or any other GA aircraft), the more I think about it.  In carrier ops, it's critical for setting the aircraft at the proper angle to ensure snagging the intended arresting cable, or for use in extreme high AOA flight such as during ACM.

As far as which types of planes are easier to fly, (GA or Tactical), they each have different characteristics that need particular attention to fly them safely and effectively.  However, there is no comparison between the complexity of systems used in a tactical jet compared to the simplicity of a Mooney.  Also, the MISSION for which the tactical aircraft is flown is where the largest difference exists between the two.  When I was flying in the military, you would either be flying some sort of tactical training flight, (ACM, AWIs, Low Level, etc.), or your flight was an "Admin Hop", meaning you were just motoring between two points.  Now that all I fly is GA, all my flights are "admin hops".  Not that it isn't enjoyable.  However, as I recall, most of my military flights could be compared to high pressure athletic competitions, where afterward, you are exhausted, soaked with sweat, exhilirated, and ready for a beer!  (Jake, former Marine F-4S pilot, T-2C instructor Kingsville).

 

[N57039]

As a relatively low time GA pilot (mostly Mooney and glider hours) who had the chance to transition to legacy Learjets and Falcon 20,  I had to laugh at the comment that GA aircraft could be easier to fly than a fighter. For sure you can't not consider the systems aspect, but the speed difference makes all the difference. Approaches, en route planning, even weather avoidence occur in slow motion in the Mooney in comparison to a humble subsonic jet. My aviation hat is off you you military pilots and your flying skills.   Thank you for your service.

 

[fantom]

I just checked out this most interesting AOA discussion, without much new to add. An AOA indicator is a neat way for the wing to talk to us, and like air conditioning, once you're used to it....

Last time I strapped on a G-suit in anger was 25 years ago, in the Air Force, F-4's, which yes had an AOA indicator. Later E models, when fitted with leading edge slats had them extend automatically when AOA exceeded six degrees, and retract when the AOA went back to four degrees. Installation of the slats required removal of the BLC system.

For GA, it's at best, a nice to have. There is an outfit that used to offer a GA AOA unit, but I don't know if they're still in business. The unit wasn't STC'd or PMA'd, a 337 and field approval was required, the issue of major or minor alteration was nebulous, and installation and calibration looked be complex.

If anyone want's to investigate it, this was their website: http://www.alphasystemsaoa.com

[Guest Anonymous]

Quote: fantom

If anyone want's to investigate it, this was their website: http://www.alphasystemsaoa.com

[KSMooniac]

Very interesting discussion...as an aero engineer I appreciate the data from an AOA gauge and would love to have one in the Mooney.  I'm not sure if/how it would change my flying, but I'm geeky enough to just want the data.    I suspect it would indeed be very handy for max performance t/o and landing ops once you get some experience with it, but we rarely need that little margin in our birds, IMO.

Buster, I have a classmate/friend that just relocated to Vegas from Edwards.  I flew my Mooney out there last year, unforunately before he relocated, but need to do so again.  It would be great to get together out there sometime, especially if you find acquire your K soon.