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Vortex generators on an Ovation?


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47 minutes ago, daytonabch04 said:

Does anybody have them installed on a Bravo?  Any differences?

I have them on a Bravo - I haven't taken a trip since they were installed, but even if I lose a 3-5 knots on cruise, for the difference in low speed I feel it's worth it. The airplane feels much more controllable at 65-70 knots than before.

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1 hour ago, LANCECASPER said:

I have them on a Bravo - I haven't taken a trip since they were installed, but even if I lose a 3-5 knots on cruise, for the difference in low speed I feel it's worth it. The airplane feels much more controllable at 65-70 knots than before.

Would be interested in your feedback after you take a long trip and see some pictures of them installed on a Bravo.  It's definitely on my wish list..

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Hmmmmm....

Good news / good news with some back-up from another TC’d user....

Bravo, slow speed, will be very much like the NA Long Bodies... so the reported improvements will apply nicely...

Where it gets more interesting is...

the Bravo flies in the FLs more often than the NA birds... making the VGs even less draggy... in cruise...

For a similar comparison... using VGs on a TC’d Mooney... Erik has them on his Rocket... and wrote about them a while ago... they were removed for paint... and put back on....

Best regards,

-a-

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  • 1 year later...
On 11/6/2019 at 9:06 AM, LANCECASPER said:

I have them on a Bravo - I haven't taken a trip since they were installed, but even if I lose a 3-5 knots on cruise, for the difference in low speed I feel it's worth it. The airplane feels much more controllable at 65-70 knots than before.

Did you ever take a long trip and see if there was any difference and if so how much?

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16 hours ago, Will.iam said:

Did you ever take a long trip and see if there was any difference and if so how much?

No noticeable difference in cruise that i can tell. I'm sure they have to add a negligible drag,  since you've added something that wasn't there before. But they also clean up and direct the airflow better. Even if they cost a couple knots, the slow handling improvements are well worth it.

(Sorry @daytonabch04 I hadn't noticed your post before)

 

Side point: In a partnership I was in on a Piper Meridian back in 2002-2004, the gross weight mod that Piper came out with included Micro VGs. We noticed all of the improvements mentioned already and, again, no noticeable difference in cruise speed. 

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Annie Brogan owns Micro Aerodynamics, I’ve done quite a bit of work with her and her VG’s, First getting the STC on the aircraft we manufactured and then in testing as we noticed an interesting phenomena that hadn’t been noticed before, 

That is on an Ag plane the vortices seem to mix with the spray and more evenly mix it, making your swath width wider and more even, both very desirable.

‘Anyway, you need to understand why and how VG’s work and what they do. They create vortices of course and theoretically this energized airflow will stick to an airfoil in higher angels of attack before it separates and this separation is of course the stall.

You see them very often on Airliners and other intensively studied and designed aircraft, but here’s the thing, you only see them in a few places and those are places that need “fixing”, you don’t see them across the entire wing, and you have to wonder why not?

They do have draw backs of course, reference TANSTAAFL . They do increase drag, where do you think the energy comes from that’s added to the airflow? Icing is another consideration, I keep seeing icing systems referenced in this forum, and well if icing is any kind of possibility, you certainly don’t want VG’s accumulating ice.

Another is that if three are missing, the aircraft is grounded, and line boys love to drag fuel hoses over VG’s and they pop off or get bent.

‘They make washing and especially waxing a real PIA.

Loctite Depend is the “special” glue used to hold them on, there are green plastic sticky templates used to position them for the install, we found it better to not remove the adhesive backing and tape them in place instead, you use a scotch rite pad to roughen the paint, apply an adhesive primer from a spray can and glue them on with the Loctite Depend, which has a relatively short shelf life so be sure to check that, it’s plainly printed.

The adhesive is really tough, but here is the thing, you glue them onto the paint, so it’s the paint bond that often fails, so to install them “right” it need to be on alodined paint free metal, which means stripping the wing of course but be careful when you spray the wing because the VG’s do work and if you not careful it makes for overspray.

‘If you install on a painted wing, pre paint the VG’s before installation of course, a very easy way to do that is simply stick them onto a roll of tape, that holds them in place and masks off the bottom where the glue goes so it’s not painted.

They come in plastic boxes and there are extra VG’s, paint them too and carry them with you just in case you need to replace some when traveling.

Also if you ever repaint the airplane, Annie will sell you a “repaint” kit that is just the VG’s and no STC paperwork for a small fraction of the original price, most of the price is for the STC and not the materials.

 

Edited by A64Pilot
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I’ve never had the VGs pick up and ice and when the TKS system is running you can actually see the fluid hit the VGs and get dispersed aft. I asked Annie about this since I didn’t want to affect the FIKI certification and I was told that the VGs do not adversely affect the TKS system. This has been my experience as well and I believe at least one other person on this forum with VGs and TKS.

I’ve seen booted planes with VGs (mostly twins) and although icing would be more of a concern to me in those situations I’m not aware of any instances where this has been a problem. 

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7 hours ago, carusoam said:

VGs and TKS... naturally invite @aviatoreb to the conversation...

 

Do we have a contact for the VG company/Annie?

Best regards,

-a-

you call?

My feeling is that whatever is lost due to tks is already lost - just like speed mods don't add often to make even faster numbers in this case "anti" speed mods don't add.  The flow is already tripped due to the tks and the cruise speed is reduced a bit - the vortex generators do no further damage to the flow.

If vortex generators do any damage to the flow of a clean wing is debatable - the company claims no the cruise speed is unaffected and I find it at least plausible since they supposedly sit in the boundary layer at cruise speeds.

The effect on low speed handling is unmistakable.  Crisper low speed handling and reduced landing touch down speeds due to reduced stall speed.

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I received my VG box this week. Once I figue out which ones get which color, I'll be installing them during the annual in May.  I am convinced from this thread and some others, that they will be worth the additional safety factor. Even if it has some trade of in top speed.  I am looking forward to experiencing the change in improved handling. 

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4 hours ago, spistora said:

I received my VG box this week. Once I figue out which ones get which color, I'll be installing them during the annual in May.  I am convinced from this thread and some others, that they will be worth the additional safety factor. Even if it has some trade of in top speed.  I am looking forward to experiencing the change in improved handling. 

Will you do any speed testing - before and after?

Yeah - safety - if we ever need to stop and make a shorter landing - its all about touching down with as little energy as possible which is facilitated with these things.  

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+1 for grabbing some before and after speed tests...

It will be too late to go back, and get before speeds....  :)

 

Things going on near the boundary layer... the air is relatively slow there... 

it’s kinda stuck to the wing...

The air is less dense on that side.... according to that lift principle...

The air will be even less dense at cruise altitudes...

 

PP amazement on how such a small device, works so well at lowering stall speed, and not affect the cruise speed significantly...

Best regards,

-a-

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  • 5 months later...
54 minutes ago, Healthpilot said:

I am considering installing these on my Ovation 3 any additional test/feedback? @ilovecornfields what model Mooney have you installed the VG's on? If you decide to remove them will they damage the paint?

I think @aviatoreb has experience removing his, but I haven’t tried to remove mine. I have a 2000 FIKI O2 with the 310 HP STC so it’s a little slower than the non TKS Ovations. I didn’t notice a change in cruise speed and according to the VG company they don’t affect the FIKI certification. Crosswind landings are WAY easier, though.

I have noticed that my wing looks 200% more awesome, though.

ACE2DB39-6EA6-47F6-AF5A-55BDBFD672E4.jpeg

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27 minutes ago, ilovecornfields said:

I think @aviatoreb has experience removing his, but I haven’t tried to remove mine. I have a 2000 FIKI O2 with the 310 HP STC so it’s a little slower than the non TKS Ovations. I didn’t notice a change in cruise speed and according to the VG company they don’t affect the FIKI certification. Crosswind landings are WAY easier, though.

I have noticed that my wing looks 200% more awesome, though.

ACE2DB39-6EA6-47F6-AF5A-55BDBFD672E4.jpeg

Your wing DOES look 200% more awesome.  So does mine!

No I have no experience flying with out them.  But I can say I stall slower than book, its crisp right down to stall and yes cross winds are easier.

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10 minutes ago, ArtVandelay said:


To each his own I guess…so much for the smooth sleek lines of your formerly laminar flow wings.

I have to admit I haven’t lost any sleep over the loss of my “formerly laminar flow wings.” I don’t think I lost any airspeed, either.

I do get a smile every time I land in a strong crosswind and feel like I have more rudder authority than I could ever ask for. Or when I land at a short strip and think “wow, that was easy!” I’m sure if I crash in a field somewhere I won’t be sad that the decreased energy (v squared, remember?) makes it more likely that I’ll survive.

To each their own…

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1 hour ago, ilovecornfields said:

I have to admit I haven’t lost any sleep over the loss of my “formerly laminar flow wings.” I don’t think I lost any airspeed, either.

I do get a smile every time I land in a strong crosswind and feel like I have more rudder authority than I could ever ask for. Or when I land at a short strip and think “wow, that was easy!” I’m sure if I crash in a field somewhere I won’t be sad that the decreased energy (v squared, remember?) makes it more likely that I’ll survive.

To each their own…

It was the safety of touching down at lower kinetic energy which was the number one reason I started shopping for them.

Number 2 is manipulating complex flows with cute little gadgets is cool and appeals to what I actually do for my day job.    And all the reasons you said.

ONLY down side is waxing the plane is slightly harder.

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20210603_091102.thumb.jpg.bb2a6a0bf20c463c4cab2ce79a3a0028.jpg

On 4/2/2021 at 7:58 AM, spistora said:

I hadn't planned to but I will if I get a chance.

I did a one pre and three post flight tests. The first showed slightly slower, the second showed slightly faster and the third was slightly slower. In the end, the average of the three post flight test showed less than a knot slower on my K. The weight and CG of each flight was similar but may of had enough difference to influence the numbers.  I did float down the runway more than normal on my first landing, there is a noticeable effect.

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The cool things about the extra drag of these talented devices….

1) They are really far back from where the laminar flow is most important….

2) When flying a TC’d or TN’d Mooney… the air is pretty thin in the O2 levels…. Making the measurable drag become really hard to measure….

3) If you frequent short fields… these devices have a tendency to lower your stall speed, thus your approach speed… making braking distances really shorter.  PIC still has to be really qualified for landing on short fields… :)

 

Really mentally tough to add things to a Mooney like another antenna, AOAi, or VGs…. For all that drag…

Getting a turbine engine would help with the decision making… :)

Best regards,

-a-

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