Horten Ho 229

[davparlr]

Some fighters are not recommended for certain maneuvers.

Indeed! It is not unusual for aircraft, including fighters, to have a limited operating envelope for various operational configurations, certainly with external stores including fuel. The F-4 was notorious for departing when maneuvering with certain store configurations. Generally speaking, external stores are jettisoned prior to engaging in combat (F-86 procedures required retuning to base if external fuel was not jettisonable). If we address the aft tank of the P-51 as similar to external stores, then a limited performance envelope until burn off to a stable configuration is reasonable and equivalent to jettisoning tanks prior to combat.

 

[davparlr]

But they still have to climb to, and descend from that altitude, just like any other aircraft.
That in itself is exposing them to some pretty extreme climatic conditions.

Surely they don't have to restrict them to perfect weather missions only.

Maintainability of the RCS coatings of the B-2 have been an on-going issue for a long time and I think they have implemented an upgrade to mitigate that (it's been a long time since I was on the program). It does not hamper operational effectiveness. In Kosovo, in miserable weather that grounded Navy and AF aircraft, the B-2 was able to destroy 40% of the identified targets with only 10% of the missions.

 

[stona]

I believe that the weather-related problems of the B-2 are because of the radar-absorbent coating. The Germans are unlikely to have had RAM, although they probably had the theoretical knowledge to make them (so did the British, the Americans, the Japanese, the Russians, the Italians, ....)

The Horten aircraft were finished in standard aircraft lacquers.

Cheers

Steve

 

[Monkeyfume]

I've followed a number of these 'Luft 46" type aircraft with interest for some years, and the Gotha/Horten prototypes have recieved their fair share of attention. There was even a documentary a few years back where a replica prototype was made in the US. While the original example might be on display one day in a museum, it would have been extremely unlikely that this novel aircraft would have made it past the testing stage. Other advanced Luftwaffe jets were well and truly ahead of this one in terms of production readiness, and they never got their chance either. In my opinion, it is the "futuristic" appeal of the Ho-229 that maintains the interest generated in it, far apart from the practical or tactical application of what might have been. The Arado flying wing jet bombers had much more potential than this one, as did the designs of Dr Lippisch. However, the Red Skull in the "Captain America" movie had a flying wing that bore an uncanny resemblance to the Ho 229......

E.555 was cancelled in '44 as it was too complicated/expensive. H-IX was still being developed at the end of the war and we realistically can only guess as to what it could have become.

 

[Monkeyfume]

The Horten aircraft were finished in standard aircraft lacquers.

From Wikipedia:
After the war, Reimar Horten said he mixed charcoal dust in with the wood glue to absorb electromagnetic waves (radar), which he believed could shield the aircraft from detection by British early warning ground-based radar that operated at 20 to 30 MHz (top end of the HF band), known as Chain Home.

Never used, but potentially could have been.

 

[Capt. Vick]

I have always thought of this as bunk! But couldn't it be answered with a simple test by the Smithsonian? Let's put this to bed already.

 

[GrauGeist]

I have always thought of this as bunk! But couldn't it be answered with a simple test by the Smithsonian? Let's put this to bed already.

When tests were conducted on the Ho229 at the Smithsonian, it was found to contain graphite embedded in the surface laminate. They also tested the original airframe with WWII era radar and it did return a low signature.

You may recall that they built a 1:1 scale replica based on original blueprints and rebuilt it as close to original as possible. This was tested at Northrup's facility and found that the Ho229's design did indeed have a reduced signature. So, for example, had the Ho229 crossed the channel on a mission, the British radar would have about a 20% reduction in detection, allowing the Ho229 to get closer than a conventional inbound enemy aircraft before it's signature was detected.

So it's not bunk, it is real! Here's a link to NatGeo's page for all the details: "Hitler's Stealth Fighter" Re-created

 

[davparlr]

When tests were conducted on the Ho229 at the Smithsonian, it was found to contain graphite embedded in the surface laminate. They also tested the original airframe with WWII era radar and it did return a low signature.

The B-49 was shown to disappear from radar in certain attitudes and it was certainly not designed for radar avoidance. The very shape of the Ho 229 could show reduced RCS. With the front mounted engines with straight inlets, the compressor blades, which act as rotating radar reflectors, would light up a radar scope from the forward quadrant. So too, maybe with a bit less reflectivity, turbine blades buried deeper, would the the rear quadrant. Putting on special paint to reduce radar reflectivity would be like a hunter dressing up in camouflage and then putting on a day-glo vest for protection.

 

[GrauGeist]

Reimar was onto something, there's no doubt about it. He spent a great deal of time with Naval engineers, in an attempt to defeat radar detection.

I agree that the very profile of the Ho229 presents a low RCS by virtue of design, however, how sensitive was WWII era radar in respect to the turbojet inlets, versus what we know and use in modern radar technology/stealth profiles?

In otherwords, technology has taken a quantum leap in the 70 years or so since that technology was employed. Back then, a U-Boat could talk to Berlin on it's two-way with an antenna that was the length of the boat and required a great deal of power. Now, we can do the same thing with a hand-held device using only a few volts and an antenna that's less than an inch.

So radar technology today is highly sophisticated, extremely sensitive and has a broad range of counter-measures versus the archaic "analog" systems of WWII.

 

[thedab]

it is bunk,that test was with the 1940 chain-home radar using 22-25 MHz from about 42 the British were using centimetric radar working on 3GHz of 10cm wavelength,like what they had on the H2S radar

 

[GrauGeist]

CHEL had an extremely short range and was used in conjunction with CHL which had the range, but not the low altitude detection of CHEL...

And I am willing to guess that the engineers at Northrup-Grumman were well aware of the various frequencies used during the late war period.

 

[stona]

When tests were conducted on the Ho229 at the Smithsonian, it was found to contain graphite embedded in the surface laminate. They also tested the original airframe with WWII era radar and it did return a low signature.[/url]

The tests were conducted only on the nose cone, not the entire structure. If I tested the air dam on the front of my car I might conclude that the entire body was constructed of composite materials, but it isn't.

The Ho 229s low radar signature is due to it's lack of two of the structures which caused a large component of the radar reflection of more conventional aircraft of the day, a vertical fin(s) and a propeller disc(s). It is not due to any intentionally built in stealth.

A large contribution to the stealth of modern aircraft is in the careful design of their geometric shape, to minimise reflection. The shape of the various Horten projects owes absolutely nothing to this consideration, and everything to attempting to make them fly controllably. Any stealth properties of the aircrafts' shapes were purely coincidental.

The first time that either of the Hortens implied that there was some kind of stealthy aspect in the design of their aircraft was Reimar in the 1960s, when such technology was being seriously developed. The pertinent question is why he, who was still involved in aircraft design and was chasing contracts, might say such a thing with the benefit of hindsight?

Cheers

Steve

 

[Milosh]

Wasn't the Mosquito hard to detect with radar?

 

[Capt. Vick]

Why would the Horten brothers have bothered putting RAM of what was essentially a POC airframe? I think the jury is still out on this point at least. Just my gut feeling.

 

[Monkeyfume]

Wasn't the Mosquito hard to detect with radar?

No.

 

[FLYBOYJ]

Wasn't the Mosquito hard to detect with radar?

No.

Actually the Mosquito did present a lower RCS than other aircraft of the same shape and size and I believe the Mosquito carried a taylored transponder (IFF) to address this. It wasn't invisible, just a little harder to see at times, if one was to see an old radar screen and how targests were acquired this would be apparent, especially if dealing with any kind of clutter or interferance. I think if you search older posts this was discussed in length.

The tests were conducted only on the nose cone, not the entire structure. If I tested the air dam on the front of my car I might conclude that the entire body was constructed of composite materials, but it isn't.

I think the Northrop team that constructed the replica found there was graphite impregnated in other parts of the structure as well

The Ho 229s low radar signature is due to it's lack of two of the structures which caused a large component of the radar reflection of more conventional aircraft of the day, a vertical fin(s) and a propeller disc(s). It is not due to any intentionally built in stealth.

A large contribution to the stealth of modern aircraft is in the careful design of their geometric shape, to minimise reflection. The shape of the various Horten projects owes absolutely nothing to this consideration, and everything to attempting to make them fly controllably. Any stealth properties of the aircrafts' shapes were purely coincidental.

The first time that either of the Hortens implied that there was some kind of stealthy aspect in the design of their aircraft was Reimar in the 1960s, when such technology was being seriously developed. The pertinent question is why he, who was still involved in aircraft design and was chasing contracts, might say such a thing with the benefit of hindsight?

Cheers

Steve

Agree 100% Stealth technology is not one or two technologies applied to aircraft construction but a combination of technologies that took years to develop and evolve into what we have today. Along the way, some designs revealed a piece of the puzzle (the Mosquito low RCS, the low RCS encountered on flying wings, etc.)

Although this technology is not foolproof, it is a game changer. The Hortens may have been on the right track in their thinking but were still years away from developing a true stealth aircraft.

 

[swampyankee]

From Wikipedia:
After the war, Reimar Horten said he mixed charcoal dust in with the wood glue to absorb electromagnetic waves (radar), which he believed could shield the aircraft from detection by British early warning ground-based radar that operated at 20 to 30 MHz (top end of the HF band), known as Chain Home.

Never used, but potentially could have been.

Belief is cheap; ask any body who's a fan of the Chicago Cubs. In any case, working radar-absorbing materials don't use charcoal.

 

[Capt. Vick]

Yeah. This makes sense. Let me mix a little charcoal in with the wood glue that holds the plane skins together. Never mind the unknown consequence this might have on it's bonding ability, and let's ignore the fact that the Tego Film factory was bombed and the replacement glues failed spectacularly during a high profile He 162 fly over. Really? REALLY? Does anyone else feel that hearsay, unspecified sources and just plain bunkery have made the uncompleted V3 and to some degree the V2 prototypes into something that was more wished than reality-based?

Questions (to my mind) that need to be answered

1) Was RAM, in any way, shape or form used in the construction of the jet powered Horten flying wings, through direct analysis of the (apparently) only surviving article.

2) Review of the transcript of the National Geographic "documentary" in order to specify the claims made in it and systematically judging their merit based on known facts or in lieu of that an educated guess.

3) Confirmation about what happened to the remains of the V2 after it's fatal crash.

 

[blueskies]

Yeah. This makes sense. Let me mix a little charcoal in with the wood glue that holds the plane skins together. Never mind the unknown consequence this might have on it's bonding ability, and let's ignore the fact that the Tego Film factory was bombed and the replacement glues failed spectacularly during a high profile He 162 fly over. Really? REALLY? Does anyone else feel that hearsay, unspecified sources and just plain bunkery have made the uncompleted V3 and to some degree the V2 prototypes into something that was more wished than reality-based?

Questions (to my mind) that need to be answered

1) Was RAM, in any way, shape or form used in the construction of the jet powered Horten flying wings, through direct analysis of the (apparently) only surviving article.

2) Review of the transcript of the National Geographic "documentary" in order to specify the claims made in it and systematically judging their merit based on known facts or in lieu of that an educated guess.

3) Confirmation about what happened to the remains of the V2 after it's fatal crash.

Adding charcoal was hardly some unknown.

If you have a formaldehyde resin then the addition of charcoal will improve curing times with the addditional benefit of slightly improving strength.

Imho this is by far the most likely reason for charcoal being present in the 229.

 

[GrauGeist]

The Tego film was a very reliable laminate adhesive used worldwide before the war and was on a par with the laminate adhesives used by the Allies for their aircraft construction.

It was the alternate laminate adhesive, manufactured by Dynamit after Golmand's factory was bombed, that was the culprite behind the delamination failures on several Luftwaffe aircraft. It was due to a corrosive reaction to the wood after it had cured, that caused catostrophic failure under stress.