M20J In-Wing Radar

[AF M20J]

Hello everyone!

Did anyone ever find use for the in-wing radar systems?
I found it to be pretty useless in general, and am wondering if anyone had experience otherwise....

[toto]

I’ve never seen a wing-mounted active radar system in an M20J. 

If you’ve got one of these installed, I’d be very curious to see photos. 

[toto]

For what it’s worth, I have an old Stormscope installed, and I think it’s awesome - despite a late-80’s monochrome UI. I really like having a real-time sferics source to confirm the delayed Nexrad.

Tbh, I’m not sure whether you were talking about weather radar - but that’s what I assumed?

[M20F]

 

[toto]

5 minutes ago, M20F said:

 

Interesting - til

 

[A64Pilot]

There may have been recent electronic advances, but Radar on smaller aircraft has never been of much use due to the limitation of antenna size

[EricJ]

1 hour ago, AF M20J said:

Hello everyone!

Did anyone ever find use for the in-wing radar systems?
I found it to be pretty useless in general, and am wondering if anyone had experience otherwise....

I've never run across one that was functional. 

 

[AF M20J]

Indeed, it has an in-wing radar system, that I think is ineffective due to the absolutely tiny aperture...
It does work, but again, not in a way that is useful to me.
It is definitely *not* a strikefinder. I also have a strikefinder.
The Radar system has an ancient monitor which was surprisingly light, given the tech involved. The radar antenna was not.

IIRC, only 6 J's from '81 were delivered with the option (can't recall the source of that info though)

[EricJ]

5 minutes ago, AF M20J said:

Indeed, it has an in-wing radar system, that I think is ineffective due to the absolutely tiny aperture...
It does work, but again, not in a way that is useful to me.
It is definitely *not* a strikefinder. I also have a strikefinder.
The Radar system has an ancient monitor which was surprisingly light, given the tech involved. The radar antenna was not.

IIRC, only 6 J's from '81 were delivered with the option (can't recall the source of that info though)

I think if you compare the lateral width of the antenna with a typical weather antenna from a light or medium twin or even regional jets, they're comparable or at least not hugely different in many cases.   It doesn't need much.    The wider it is laterally the narrower the beam width, which is what provides the lateral resolution.    Because it is small vertically, the vertical resolution won't be very good at all, but most people don't care about that nearly as much as they do about the horizontal resolution.    Unless you need the information to fly over or under whatever it is in front of you, the lateral resolution is the most useful.

There may be other limitations on that system that result from light weight or low cost, but if it is limited, which I don't doubt, I don't think the antenna is the biggest issue.

[GeeBee]

The problem with that system is not antenna size, but antenna size relative to receiver sesativity. If you could couple that antenna with some of the newer R/T units it would be a reasonable unit. As it is, nobody is interested because it is a miniscule market and it would require a completely new system including antenna, smal and odd though it may be.

The new R/T units are so sensative that the transmiiter puts out less power than your home microwave is allowed to leak. This of course requires a sensative receiver (a deaf man hears nothing at a rock concert). A more sensative receiver can use smaller a antenna.

 

[A64Pilot]

Sure you could build a RADAR with a smaller antenna now, but not then. Ever wondered why an F4 and an F-15 were so big, and why an F-16 has such a big nose? It’s for antenna size, the pie are squared thing, antenna surface area is so important. 

Look at the Fire Control Radar Antenna on the AH-64D, it’s as big as they could put on the aircraft, it would be bigger if they could have made it so, and trust me it’s an extraordinarily sophisticated RADAR costing millions and highly classified but the bigger the antenna the more a RADAR can discriminate.

RADAR has come a long way, one on my boat was a frequency modulated continuous wave RADAR, no more main bang, a continuous wave that modulates the frequency and its power output was tiny, no health hazard at all. But it essentially didn’t exist in the civilian world just a few years ago.

[GeeBee]

Fire conrol radar and wx radar are two different missions. You don't need the kind of resolution in a transport aircraft as you do in a combat aircraft. We are talking wx radar here.

[Guest]

From the IPC 

[A64Pilot]

19 hours ago, GeeBee said:

Fire conrol radar and wx radar are two different missions. You don't need the kind of resolution in a transport aircraft as you do in a combat aircraft. We are talking wx radar here.

Got it, so why are small aircraft Wx RADAR’s pretty much never seen anymore? It’s not because of ADSB, Transport Category aircraft have Wx RADAR still.

It’s because it just doesn’t work very well.

But with the death of the magnetron and possibly a phased array, maybe we will see a resurgence of the small RADARs, the C-210 had an under wing mounted pod, that way they could get a 10” antenna in there, that wouldn’t have been done if an in wing worked nearly as well.

Speaking of Wx RADAR, ever seen those huge golf balls? Those are Wx RADARS.  Size matters greatly with RADAR, look at the surveillance RADAR at an airport, it’s so big for a reason. 

This is the Frequency Modulated Continuous Wave RADAR I had on the boat, due to beam sharpening and the difference in operating principle from a Magnetron RADAR  (it measured Doppler) it was outstanding for squall detection (Wx RADAR) but your not putting it a wing. Not yet, maybe coming in the future, but the old Magnetron small RADAR’s just couldn’t discriminate much.

 

https://www.nmea.org/Assets/navico-brands-broadband-4g-radar.pdf

24” antenna I think

 

 

[GeeBee]

Those huge golf balls contain NEXRAD which requires lots of power to project a beam without attenuation because there is a requirement to see through the storm and beyond for several hundred miles.. Aircraft don't need that, because you don't fly through attenuating weather.......ever. All you need to see on an aviation radar is what is before you, not what is beyond the storm. Further, modern systems have attenuation alert, so simply put, they have built in a system to warn you that the beam is being attenuating . Again, we are talking airborne weather radar which is a different mission from fire control radar or ground based Nexrad radar.

As to small aircraft radars, TBM, Daher and others use the Garmin 10" radar antenna. It will fit in those "pods" on the C-210 etc.  It works quite nice, especially the GWX-8000 and guess what? Its max  antenna is 18". Don't need bigger. Gone are the old 30 inch days.

 

[carusoam]

The whys….

We have two resources that work…

The strike finder… or other spherics type detectors for tactical navigation around the storm… in real time.

and ADSB or nexrad fancy color graphics for better big picture reasons… with a few minutes of delay…

 

Trying to put a radar on a Mooney typically ran into a huge draggy surface that kind of got in the way….  That and price….

And… how to operate the simpler radars also caused some issues… the first storm absorbed all of the energy, leaving a clear area behind it… the clear area was a bigger storm, but the radar didn’t know it was there…

It would be interesting if Big G wanted to sell a Mooney sized radar… if they have updated radar systems the way they did Navigation for Mooneys…

Best regards,

-a-

[EricJ]

15 minutes ago, carusoam said:

Trying to put a radar on a Mooney typically ran into a huge draggy surface that kind of got in the way….  That and price….

Cost, weight, power consumption, maintenance, panel space...all trades for not a tremendous amount of benefit compared to strike finders or looking out the window.   For non-FIKI airplanes or airplanes with essentially no anti-ice or de-ice capability there's not much reason to be navigating anywhere near where one of those radars would be necessary.   As you say, these days ADS-B-in or Sirius-XM gets you nearly all the way there with a relatively small delay.    ADS-B-in is available for free to be displayed on your EFB and/or your in-panel GPS display.   It would be hard to justify having even a modernized version of the radar in most of our airplanes even these days.     I can see the utility on many pressurized airplanes, or maybe FIKI turbo'd twins but not so much on ours.

[carusoam]

On 9/18/2022 at 1:00 PM, AF M20J said:

Hello everyone!

Did anyone ever find use for the in-wing radar systems?
I found it to be pretty useless in general, and am wondering if anyone had experience otherwise....

Most of the discussions around here… are the cost of removal of the old systems…. Lots of sheet metal work to consider…

And the benefit of the UL increase…

Best regards,

-a-

[GeeBee]

Here in the south there are times when I could benefit from the utility of real time weather detection. Times when I diverted or cancelled because I feared too much latency in other systems.  It is much like FIKI, you don't need it often, but it does increase the utility of the airplane albeit at the expense of UL. 

Personally, I think it could be accomplished very nicely with a real time Nexrad network broadcasting locally. Don't see the dollars for that forthcoming though. It could be accomplished on the ground side fairly cheaply.

[A64Pilot]

On 9/26/2022 at 6:32 PM, GeeBee said:

Those huge golf balls contain NEXRAD which requires lots of power to project a beam without attenuation because there is a requirement to see through the storm and beyond for several hundred miles.. Aircraft don't need that, because you don't fly through attenuating weather.......ever. All you need to see on an aviation radar is what is before you, not what is beyond the storm. Further, modern systems have attenuation alert, so simply put, they have built in a system to warn you that the beam is being attenuating . Again, we are talking airborne weather radar which is a different mission from fire control radar or ground based Nexrad radar.

As to small aircraft radars, TBM, Daher and others use the Garmin 10" radar antenna. It will fit in those "pods" on the C-210 etc.  It works quite nice, especially the GWX-8000 and guess what? Its max  antenna is 18". Don't need bigger. Gone are the old 30 inch days.

 

Yes the 10” RADARs have some utility, especially before XM Wx and ADSB, but they won’t even come close to fitting inside of a Mooney’s wing, not even close, and the topic is in wing RADAR, not 10” RADAR in an under wing mounted pod. 10” is the size of a dinner plate, in wing maybe 3” or so?

Then we aren’t talking about modern RADAR’s either, but the old Magnatron in wing RADAR’s.

In wing RADAR is about as useful as that little Strike Finder thing I have, compared to the cost, you get very little benefit.

[GeeBee]

Of course and there is no need to fit it in the wing. A 10" unit can fit quite nicely in a slipper pod, as the TBM or the Bonanza does. A Garmin GWX 8000 would be both functional and useful in such a configuration but I doubt most Mooney owners would give up the speed penalty. Further it may in fact put the airplane over the 61 knot limit, I don't know, only flight testing could tell. It is not impossible but neither is it profoundly marketable.

[A64Pilot]

An old 10” RADAR was marginal in utility, but it was certainly better than nothing, I’ve flown them, and in some extent they are dangerous as since your RADAR equipped and what it shows isn’t that bad you will drive on, but it can only see what’s directly in front of it, the cell just behind it can be a hail filled killer and you won’t see it in time to do anything. 

But with the old Magnatron technology anything that would fit inside on a Mooney wing would be pretty much worthless.

Back in the day RADAR power was in the tens of thousands of watts, in pulses, like a strobe. The FMCW wave Marine RADAR I linked to’s power output was 1/5 the output power of a cell phone, but it’s continuous. Maybe one day soon a working RADAR could have an antenna the size of a pack of cigarettes, but I don’t think it’s happened yet and I’m certain back in 1981 it didn’t.

I think maybe if the market existed we might have it now

[GeeBee]

I think it has to be a newer power transistor radars for it to be of value. Think of it. With these units, an 18" performs as well as an magnetron 30 inch.

 

[A64Pilot]

21 minutes ago, GeeBee said:

I think it has to be a newer power transistor radars for it to be of value. Think of it. With these units, an 18" performs as well as an magnetron 30 inch.

 

That’s not due to the transistors, but beam sharpening, I think the biggest difference was the old Magnetron units were Analog, where the new RADARS are now Digital and digital signal processing is so much more effective.

The transistors enable lightweight and Magnetrons were very life limited and degraded from day 1, so they lost effectiveness over time, they also gave off lots of heat too. It’s literally comparing an old tube radio to a modern digital radio, same thing.

FMCW is a completely different operating methodology too, completely different

https://www.automation.com/getattachment/d201a032-1c4b-4885-b41b-b2c0400b3cd2/FMCW-vs-Pulse-Radar-White-Paper.pdf?lang=en-US&ext=.pdf

Coming from sailboats the power a magnetron RADAR used was just too much to run often, where the modern FMCW RADAR I left on all night, nighttime you couldn’t see the squalls like you can in the day of course. I got knocked down once, that was enough.

So yes I think a whole order of magnitude of accuracy and precision is possible now with a small aircraft RADAR, is there enough market for someone to build a FMCW RADAR for airplanes?

[Pinecone]

They have the radars and the mechanics.  The issue would be getting the STC approved for enough airplanes.  And at a price that people will put them in.

Looking at Garmin Marine radars, they have 18 inch long antennas.  The total height, with mount and radome is about 10 inches.  Looking at the open antenna types, the height of the actual antenna doesn't look that tall.

But those radars do require a moving antenna.  We would probably be better off with a phased array antenna.