Replace towel bar antenna with blades

[Kvoisier]

Has anyone done this.  As I understand, it reduces drag a bit and adds a knot or 2. 

Was it a simple swap?  Same coax? connectors?

Thanks

[ArtVandelay]

Or put the antennas inside the winglets and get rid of the towel bar or blades completely.

[Bob - S50]

There was a an article in the Mooney Flyer several months ago in which it was pointed out that the blades do not reduce drag. Save your money.

[aviatoreb]

37 minutes ago, Bob - S50 said:

There was a an article in the Mooney Flyer several months ago in which it was pointed out that the blades do not reduce drag. Save your money.

I would believe that hiding them in the wing would do something though.

[kortopates]

30 minutes ago, aviatoreb said:

I would believe that hiding them in the wing would do something though.

That's what I did and picked up at least 3.14159265359 kts +/- 1 kts. Easy peasy, just a couple dozen cherry max rivets and coax!

[aviatoreb]

6 minutes ago, kortopates said:

That's what I did and picked up at least 3.14159265359 kts +/- 1 kts. Easy peasy, just a couple dozen cherry max rivets and coax!

You had me until the 7th digit then I figured you were exaggerating. +/-1

[kortopates]

3 minutes ago, aviatoreb said:

You had me until the 7th digit then I figured you were exaggerating. +/-1

Guilty! it was actually only +/- 3 kts.

 

But aesthetics are everything to Mooney pilots!

Edited November 17, 2020 by kortopates

[aviatoreb]

3 minutes ago, kortopates said:

Guilty! it was actually only +/- 3 kts.

 

But aesthetics are everything to Mooney pilots!

So its good you are absolutely positive you got .14159265359 increase in speed.

I thought 

1) speed is everything to Mooney pilots.

2) cheap is everything to Mooney pilots.

3) in third place - Mooney aesthetics.

4) numerical accuracy is everything to Mooney pilots.  Oh wait - never mind, that one's Math professors.

[kortopates]

7 minutes ago, aviatoreb said:

So its good you are absolutely positive you got .14159265359 increase in speed.

I thought 

1) speed is everything to Mooney pilots.

2) cheap is everything to Mooney pilots.

3) in third place - Mooney aesthetics.

4) numerical accuracy is everything to Mooney pilots.  Oh wait - never mind, that one's Math professors.

Some refinements, .... 

Yeah somewhere between 6.14159265359 and .14159265359

But I thought Speed is everything to Mooney Rocket pilots but Efficiency is everything to most pre-long body pilots.

But you got to have your bird looking like it fly's fast to actually really go fast - hence aesthetics like ditching the antenna farm. 

Cheap is everything to the 4 cyl Vintage Mooney pilot. 

But I wouldn't discount numerical accuracy, to many engineers and PhDs in this forum. But its humorous how we so often use it to justify our choices. 

[Hank]

24 minutes ago, kortopates said:

Some refinements, .... 

Yeah somewhere between 6.14159265359 and .14159265359

But I thought Speed is everything to Mooney Rocket pilots but Efficiency is everything to most pre-long body pilots.

But you got to have your bird looking like it fly's fast to actually really go fast - hence aesthetics like ditching the antenna farm. 

Cheap is everything to the 4 cyl Vintage Mooney pilot. 

But I wouldn't discount numerical accuracy, to many engineers and PhDs in this forum. But its humorous how we so often use it to justify our choices. 

As an engineer [MSE only, not PhD], I value numerical accuracy. Especially when discussing the efficiency of my 4-cylinder Vintage Mooney.

And Erik's Rocket looks fast on the ground, in the air and on FlightAware! If we ever travel together, that will let him land, select the FBO and pick up the rental car before I enter the pattern . . . .

Edited November 17, 2020 by Hank

[aviatoreb]

1 hour ago, Hank said:

As an engineer [MSE only, not PhD], I value numerical accuracy. Especially when discussing the efficiency of my 4-cylinder Vintage Mooney.

And Erik's Rocket looks fast on the ground, in the air and on FlightAware! If we ever travel together, that will let him land, select the FBO and pick up the rental car before I enter the pattern . . . .

:-). ??!  And plunk down my credit card before you get there?  Allll-right.  I'll rent the car and you buy the first round.

 

[aviatoreb]

1 hour ago, kortopates said:

Some refinements, .... 

Yeah somewhere between 6.14159265359 and .14159265359

But I thought Speed is everything to Mooney Rocket pilots but Efficiency is everything to most pre-long body pilots.

But you got to have your bird looking like it fly's fast to actually really go fast - hence aesthetics like ditching the antenna farm. 

Cheap is everything to the 4 cyl Vintage Mooney pilot. 

But I wouldn't discount numerical accuracy, to many engineers and PhDs in this forum. But its humorous how we so often use it to justify our choices. 

I would argue that efficiency is partly built into cheap at least.  Not entirely of course.

If I thought for a second hiding my towel bars were worth 6 knots I would do it next week.  even if 3 knots.  I am guessing it is closer to the 0.14159264359... (who here remembers the big fiasco when I posted one million digits of pie and froze people's screens?) - I am guessing 0.25kts.  Sadly.

The most major aero clean up for my bird would be more modern air scoops for engine cooling more modern style - like an acclaim.

Then next most major I bet would be acclaim - like wing tips - there's those led light wing tips but I am guessing that's like 1 knot.

Then towel bars?

Then of course the jato.

[aviatoreb]

2 minutes ago, bluehighwayflyer said:

Ha!   Hi, Erik.  That’s a deal any of us CB vintage owners would be happy to make.  
 

Jim

Just cuz I'm too polite to say no.  Not cuz I'm a big spender.  But hey - you come too and there's room in the car and you can buy the second round!

I just now noticed that pilot and polite are very closely spelled cuz I almost misspelled it.

[Hank]

27 minutes ago, aviatoreb said:

I would argue that efficiency is partly built into cheap at least.  Not entirely of course.

If I thought for a second hiding my towel bars were worth 6 knots I would do it next week.  even if 3 knots.  I am guessing it is closer to the 0.14159264359... (who here remembers the big fiasco when I posted one million digits of pie and froze people's screens?) - I am guessing 0.25kts.  Sadly.

The most major aero clean up for my bird would be more modern air scoops for engine cooling more modern style - like an acclaim.

Then next most major I bet would be acclaim - like wing tips - there's those led light wing tips but I am guessing that's like 1 knot.

Then towel bars?

Then of course the jato.

You ain't seen my towel bars! Now I gotta look for the pictures. I thought about replacing it with the wingtip whiskers, right up until I looked at how mine are attached . . . .

[aviatoreb]

35 minutes ago, bluehighwayflyer said:

I’d love that, Erik.  Truly.  

Jim

One day!!

[carusoam]

Welcome aboard Kv!

There may be some value to the newer variety of blade antennas...

Chances of re-using ancient antenna wire gets slimmer by the day....

Up for doing a minor sheet metal mod and paint project?

Was that two kias... or was that two KTs TAS?

Who has the precision data collector to demonstrate a two kias increase?
 

Is that at 10’ above SL, or at actual cruise altitudes?   
 

That NJ pilot that was proving the speed mods at 10’ASL didn’t finish the data collection...

Rounds of beer, and towel bars...

Can only mean one thing....

Mooney Summit is in the schedule..!

KOSH is where I have seen towels actually hanging on Mooneys...  it seems they are there to protect the prop... 

Best regards,

-a-

[jetdriven]

I replaced the cat whiskers with a set of blade antennas. Im not sure how the factory did it cause the fin is only 3/4" thick there and the 90 degree BNC connectors are 1"...  And i put in plates with nutplates on them, I think you'd use rivnuts.  Anyways quite a project but looks cant be beat.

looking through the photos I had quite the rat rod / parts chasing shop beater. We caught the FBO employees actually laughing at us. But it was winning air races and we could go anywhere with a VFR GPS and a VOR.

 

[Guest]

On 11/16/2020 at 7:01 PM, Bob - S50 said:

There was a an article in the Mooney Flyer several months ago in which it was pointed out that the blades do not reduce drag. Save your money.

Go to YouTube and search “Fluid Dynamics of Drag, part 4” It makes a compelling argument for streamlined versus any other shape.

Clarence

Edited November 19, 2020 by M20Doc

[carusoam]

Round shapes of the towel bar, are incredibly draggy... in the cross diameter direction.

Overall, it is a pretty small part, so the net drag won’t be very much...

PP thoughts only, not a fluid dynamics kind of guy... anymore.

Best regards,

-a-

[PT20J]

I would think the cat whiskers would have the lowest drag because they have such a small area. I would think that the towel bars would have the highest because circular cross sections are draggy. Both are ugly, though. The more aesthetic blades should have drag somewhere in between, I'd think, because they have a fair amount of wetted area. Also, I'd expect them more sensitive to mounting -- you'd want to get them at the zero-lift AoA at cruise. Perhaps @blueontop might have some better insights. 

At any rate, I am always impressed with Byron's workmanship. 

Skip

[carusoam]

Blue must be very busy... 

It has been several weeks without even a log in...

Does he know Jonny?

Best regards,

-a-

[ArtVandelay]

You can also put the epirb antenna in the dorsal fin, and marker beacon antenna beneath the fiberglass belly if you have it. So you’ll lose 2 vor, 1 belly, and 1 epirb antenna...that’s got to be 5 knots. ;-)

 

 

 

Tom

[PT20J]

Mooney put the marker beacon antenna in the belly above the fiberglass belly panel and the 121.5 MHz ELT antenna folded into the dorsal fin on my ‘94 M20J. I think the 406 MHz ELTs require the antenna to be vertical, though.

I’ve removed the ADF antenna, but I’ve still got GPS, Aspen, ELT, 2 comms, nav, stormscope, DME, and transponder. Starting to looks like an AWACS 

Skip

[Hank]

2 hours ago, carusoam said:

Round shapes of the towel bar, are incredibly draggy... in the cross diameter direction.

Overall, it is a pretty small part, so the net drag won’t be very much...

PP thoughts only, not a fluid dynamics kind of guy... anymore.

Best regards,

-a-

There's more to it than just drag from the antenna bar. Look at the structure!

So much sheet metal work to take this beast out.

[Blue on Top]

36 minutes ago, Hank said:

There's more to it than just drag from the antenna bar. Look at the structure!

So much sheet metal work to take this beast out.

Oh, man.  I really, really don't want to offend anyone, but here's a little aero and engineering straight talk  

OMG @Hank  You have peaked out with drag and ugliness, but I have to say, structurally, that thing ain't coming off.  On another great note, YOU might be able to get 3.1415926 knots of speed taking it off.  The aluminum work on your vertical is beautiful, too!

@ArtVandelay  Love the blue tail ... but I am bias.

@jetdriven  Love the red checker board tail.  Beautiful!

@PT20J wins the drag issue, though.  Cat whiskers (or TV rabbit ears) wins the low drag argument.  Although the Cd is high, there is little area, and that area doesn't change with AOA.  In addition, due to the sweep of the antenna, the cross section is really an ovular cylinder and not a circular cylinder to the airflow.  We (Mooney-Chino) actually ran all three (3) antennae in CFD to see for ourselves.

PS.  Why do TKS owners put up with the loss of 8-10 knots?  Should I start a new thread?