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Military / Re: Nuclear Weapons NEWS ONLY
« Last post by bobbymike on Today at 07:19:32 pm »
Nice find thanks for posting
Aerospace / Re: Lockheed Martin F-35: News ONLY topic
« Last post by seruriermarshal on Today at 07:16:32 pm »
F-35s have arrived on UK
Military / Re: Nuclear Weapons NEWS ONLY
« Last post by bring_it_on on Today at 07:01:45 pm »
Fiscal Year 2017 (FY17) Intercontinental Ballistic Missile (ICBM) Reentry Vehicle Applications Program (RVAP) Technology Studies
Broad Agency Announcement (BAA)..
Army Projects / Re: USMC Marine Personnel Carrier
« Last post by bobbymike on Today at 07:01:18 pm »
...walk into any engineering shop today and ask about rivets people will be think you are something as low and base as an archetict.
In aircraft construction rivets are still widely in use.
Why are planes using rivets & not welded construction?
Short answer: High-strength aluminium alloys are tricky to weld correctly. Aluminium is such a fine material for aircraft structures that the need to rivet it is gladly accepted.

Two things are important:

1.While steel has a temperature range in which it gets more and more runny, aluminium alloys change from solid to liquid within a few degrees. Also, heat conductivity in iron-based alloys is lower than in aluminium, so heating steel locally will keep the surrounding material cooler and more solid compared to aluminium. While welding thin sheets of steel is trivial, it needs lots of experience in aluminium. For very thin sheets, special equipment like a water-cooled copper backing on which the aluminium sheets rest, so their back is cooled, are needed. Also, the melting temperature of steel and titanium is high enough for it to glow long before it melts, while aluminium will melt without giving you any optical hint of its temperature.

2.High-strength aluminium is produced by progressively aging and precipitation hardening the material. The usual alloys use copper atoms dispersed through the aluminium matrix which locally distort the atomic lattice and strengthen it. If they are heated and rapidly cooled by welding, the copper distribution would be changed and the material would be weakened around the welding area. To harden the finished structure again is rather impractical in most cases, so riveting is the better alternative.

A third speciality is the oxide layer on aluminium, which has a higher melting temperature than the base material. You need an AC TIG welder to disrupt the aluminium oxide layer, so your choice of welding techniques is rather limited.

Also, riveted structures are easier to inspect and to repair. Most repairs need to remove aircraft structure for access, and a riveted structure is easier to disassemble and to put together again after the repair using slightly thicker rivets.

My experience with aluminium welding stopped at 4mm thick sheets; while thicker ones were easy to weld, I never managed to weld thinner ones. You sit in front of your structure and heat the spot where you want to start welding. Watching it through the darkened head screen you wait until the spot under the arc becomes glossy, which signals that the surface has started to melt. Now you need to add your welding wire like crazy to keep the spot from heating more, and get the spot moving. If you fail to do so, a second later you will have a hole under your arc, because the aluminium has molten completely and has fallen away. Doing this with 2mm sheets was a pure exercise in futility for me - the moment the surface became glossy it fell away already.
Listen at 7:00 this was 1954

Space Projects / Re: BAe HOTOL
« Last post by starviking on Today at 05:52:46 pm »
HOTOL as it was born

Any more information on this configuration? There would appear to be attachment points and what may be umbilical covers aft of the payload bay. For a booster? fuel tank?

Early Aircraft Projects / Re: Various Italian aircraft
« Last post by blackkite on Today at 05:07:29 pm »
Thank you blackkite
the qouted engine drawing is very interesting
Do you have a similar one for the Asso 750 or asso 750 R?
I will try to find my photos
er me
I will try to answer your question. Give me time. :)
Aerospace / Re: Lockheed Martin F-35: News ONLY topic
« Last post by sferrin on Today at 03:27:47 pm »

Aerospace / Re: Lockheed Martin F-35: News ONLY topic
« Last post by Flyaway on Today at 03:19:30 pm »
User Artwork / Re: Advancedboy's Designs Topic
« Last post by riggerrob on Today at 02:34:17 pm »
Clever the way you have integrated engines with wings on those transports.

However, on the jet hydroplane, I would crank the wings in the other direction because bolting the wings' center section directly to the fuselage would shorten load-paths and reduce interference drag. Then crank the outer wings upwards outboard of the engine nacelles. High outer wing panels will whack fewer docks, trucks, fork-lifts, etc.

The greatest challenge is making it maneuverable enough to reverse onto docks so that it can unload straight out the back end. Thrust-reversers pointing up, over top of the wings?

Either way, you still need to keep engine inlets well above the waves to minimize water-ingestion. Floats will help reduce spray directly into engine intakes.

Sorry dude, I was not trying to tell you how to draw your pretty pictures. ..... Instead, I was looking at your sketches from a truck-driver's perspective and trying to figure out the easiest way to unload cargo.
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