WW2 Stealth - DH Mosquito??

[Piper106]

I keep thinking of some facts that I think I know regarding the DH Mosquito. .
1. Materials that are not conductors of electricity generally are poor reflectors of electro-magnetic radiation.
The majority of the Mosquito was wood, a poor conductor of electricity.
2. Electro-magnetic radiation interacts weakly, if at all, with objects that are smaller than 1/2 the wave length of the energy being used.
For the early to mid war German Freya radar operating at 125 MHz (2.4 meter wave length), that would imply you need a metal object that displays a length normal to the beam of more than 1.2 meters to develop a decent return echo. The only metal on the Mosquito bigger than 1.2 meters in length would be the engine cowling and the propellor blades. Again, depending on their angle to the radar beam, the return echo might be quite weak.

Bottom line; I would bet some of those fancy high denomination chips they have at a casino that,a DM Mosquito, at least for the German Freya radar, had a significantly smaller radar return echo than similar WW2 aircraft such as a P-38 or a B-26.

While most texts tell us it was the high performance of the Mosquito that lead to its success, I would suggest that poor radar detect-ability also played a part in its success.

Piper106

 

[vikingBerserker]

That certainly seems logical. Japan discovered one of the benefits of using wooden/canvas biplanes in the kamikaze roll was a lower radar signature.

 

[Kryten]

years ago whilst in the air defence we were being taught about radar and it's limitations , the instructor used a radar emitter and an oscilloscope to show how different aspects of model aircraft gave different returns.
one of the models used was a mossie, the instructor showed how the small cross section of the fuselage and its round shape gave a much lower return than the slab sides of other aircraft!
now i'm not claiming the mossie was stealth technology, just it's shape gave poor reflection of radar signals compared to other aircraft of the time, I dont think the wood structure really came into it as the radar would have reflected off the painted surface anyway!

 

[buffnut453]

The sodding great props whirring around would still present a significant radar return, though.

 

[AirWolf]

Maybe with modern radar but not with the radar tech of ww2

 

[Jack_Hill]

Hi,
Just guessing and asking for longtime ago, but i think Mosquito's and Ho-229 stealthness might be a simple, natural consequence of their own designs.
Yes, a great operational "plus".
But, maybe, not much more than a lucky, succesfull hazard.

 

[AirWolf]

Hi,
Just guessing and asking for longtime ago, but i think Mosquito's and Ho-229 stealthness might be a simple, natural consequence of their own designs.
Yes, a great operational "plus".
But, maybe, not much more than a lucky, succesfull hazard.

The Mosquito's 'stealth' was a lucky extra, but the Ho-229 was designed to be hard to see from below.

 

[Piper106]

I agree, there was no deliberate intent by the DH engineers to reduce radar cross section. It was just a natural result or 'lucky accident' of some of the other decisions that were made regarding materials of construction and aerodynamics. Still was a nice bonus however.

Kryten remark as far as paint has been noted. Seems reasonable that aluminum pigmented dope or some types of (metalic pigment??) paint could bump the return echo up to almost the level of a solid metal construction. The flip side is that there may have been a 1940s vintage shellac, varnish, or other paints as good at protecting the wood with a far smaller radar return. Modern texts seem to indicate iron ferrite particles in a surface coating absorb radar energy and prevent radar reflection.

 

[FLYBOYJ]

The Mosquito's 'stealth' was a lucky extra, but the Ho-229 was designed to be hard to see from below.

There was an effort to reduce RCS but this was more or less a secondary consideration. "Low drag and reduced weight" was the primary design consideration of the flying wing. Horten did try to make his aircraft "stealthy." It still had an RCS way less than a BF109.

 

[FLYBOYJ]

I agree, there was no deliberate intent by the DH engineers to reduce radar cross section. It was just a natural result or 'lucky accident' of some of the other decisions that were made regarding materials of construction and aerodynamics. Still was a nice bonus however.

100%
correct!

 

[Erich]

LW sound equipment was incredibly sensitive the LW knew when any Allied A/C was in process of taking off for the Reich....... the anti Mossie units in 1944 knew when and where the Mossies were located the problem overall was the non-height advantage to take on an effective attack.

 

[FLYBOYJ]

That certainly seems logical. Japan discovered one of the benefits of using wooden/canvas biplanes in the kamikaze roll was a lower radar signature.

"Canvas" is not used to cover fabric aircraft. Irish Linen and Cotton were the main fabrics used during WW2. "Canvas" is very heavy and was used to cover access areas on larger aircraft.

 

[parsifal]

Mosquitoes were a lot of good things, but I would seriously question that it was significantly less detectable on radar than any of its contemporaries.

I confess I dont have any first hand experience at detecting wooden aircraft. However we regularly had to search for wooden hulled boats for fishing, smuggling, customs checks and the like. The radars we were using were post war developments of WWII surface radars. so better, but not greatly different. There were never any real problems finding or tracking these surface craft using that type of technoilogy.

Developing stealth tech is a very tricky business.

 

[Jack_Hill]

I may be wrong, of course but : while being real fan of Horten's brothers hard working on flying wings, i do not believe in any "stealth carbon glue" or whatever.
Those guys only wanted to make their wonderbirds fly I guess.
By any means : good glue, poor glue,good wood or poor wood, right sized engines or not, did not matters anyhow. Even Ernst Heinkel did not obtained proper glue for his 162.
What i try to say indeed is : including any cheap, disposable saw dust and carbonate matter in the gluing principle might have been a simple matter of economy, doing their best and lately after, maybe, discovering the stealth of the bird.

 

[vikingBerserker]

"Canvas" is not used to cover fabric aircraft. Irish Linen and Cotton were the main fabrics used during WW2. "Canvas" is very heavy and was used to cover access areas on larger aircraft.

I think we are just having a miss on words. In textiles, both Irish Linen and Cotton can be a type of lightweight canvas.

 

[FLYBOYJ]

I think we are just having a miss on words. In textiles, both Irish Linen and Cotton can be a type of lightweight canvas.

Very lightweight!

 

[yulzari]

LW sound equipment was incredibly sensitive the LW knew when any Allied A/C was in process of taking off for the Reich....... the anti Mossie units in 1944 knew when and where the Mossies were located the problem overall was the non-height advantage to take on an effective attack.

I presume you are referring to radio intercepts not sound ranging/direction?

 

[Tante Ju]

2. Electro-magnetic radiation interacts weakly, if at all, with objects that are smaller than 1/2 the wave length of the energy being used.
For the early to mid war German Freya radar operating at 125 MHz (2.4 meter wave length), that would imply you need a metal object that displays a length normal to the beam of more than 1.2 meters to develop a decent return echo. The only metal on the Mosquito bigger than 1.2 meters in length would be the engine cowling and the propellor blades. Again, depending on their angle to the radar beam, the return echo might be quite weak.

If that would be even remotely true, Chain Home with it's 12 meter wavalenght could have not 'see' anything in 1940... but it did.

 

[Jabberwocky]

I keep thinking of some facts that I think I know regarding the DH Mosquito. .
1. Materials that are not conductors of electricity generally are poor reflectors of electro-magnetic radiation.
The majority of the Mosquito was wood, a poor conductor of electricity.
2. Electro-magnetic radiation interacts weakly, if at all, with objects that are smaller than 1/2 the wave length of the energy being used.
For the early to mid war German Freya radar operating at 125 MHz (2.4 meter wave length), that would imply you need a metal object that displays a length normal to the beam of more than 1.2 meters to develop a decent return echo. The only metal on the Mosquito bigger than 1.2 meters in length would be the engine cowling and the propellor blades. Again, depending on their angle to the radar beam, the return echo might be quite weak.

Bottom line; I would bet some of those fancy high denomination chips they have at a casino that,a DM Mosquito, at least for the German Freya radar, had a significantly smaller radar return echo than similar WW2 aircraft such as a P-38 or a B-26.

While most texts tell us it was the high performance of the Mosquito that lead to its success, I would suggest that poor radar detect-ability also played a part in its success.

Piper106

There is no evidence, contemporary or otherwise, that the Mosquito had any passive radar stealthiness.

There are a couple of big metallic radar returns off the Mosquito. The Merlin engines (2.9 m long with mounts and firewall), the propeller cones and hubs, the landing gear, the fuel tanks, the forward and rear armour plates, the aluminium radiators, the ailerons/rudder. Not to mention the return off the windscreen, props and the aircraft itself, wooden construction not withstanding.

German radar controllers typically picked up high flying Mosquitos over the North Sea or Channel, well before they made landfall on the continent. The problem for the Luftwaffe was the combination of speed, altitude (either very high or very low), deception/jamming/spoofing and course changes to throw off intercept. The Germans also often tracked Mosquitos using Naxburg, which tracked H2S/Monica emissions.

Doug Richardson's book 'Stealth' notes that the stealth characteristics of the Mosquito were "almost nil because the radar waves that passed through the wood outer structure would reflect off internal structures, such as the skeleton, wing spars, bomb racks, the cockpit, and the engines. The Mosquito probably had a lower RCS than a metallic Lancaster or Halifax, though this amount was not militarily significant. The Mosquito's survivability was derived from its performance rather than its RCS reduction."

 

[parsifal]

The Mosquito probably had a lower RCS than a metallic Lancaster or Halifax, though this amount was not militarily significant. The Mosquito's survivability was derived from its performance rather than its RCS reduction."

If it did, it was indistinguishable. Thats how the Night fighters masquerading as a bomber ensnared Luftwaffe Night Fighters. All the German radars could see was a blob on the screen. They would then direct the defending NF in that "box" to an intercept. The poor NJG crews would never know what they were stalking...was it a 4 engined bomber, a 2 engined pathfinder, or a snarling NF ready to turn the tables...