Aircraft with strange protrusion (photos)

And a close-up further along:

dude i've totally seen this one go off into the sunset with my dad a few times with my dad,i'll start taking pictures for the next ones and those to come.

I have to be honest with you chinabean, this looks like a contrail should and its being disapated by wind in the area.

Here is another interesting test bed:





[edit on 12/22/05 by FredT]

I have tried searching for any pictures of a 707 test bed, so far without success, but on repeated viewing of the photo the obstacle does look more like a high bypass turbfan cowl than anything.

Originally posted by waynos
I have tried searching for any pictures of a 707 test bed, so far without success, but on repeated viewing of the photo the obstacle does look more like a high bypass turbfan cowl than anything.

Ask and ye shall recieve:




Honeywell Aviation Service Boeing 720-051B



[edit on 12/22/05 by FredT]

And another view:




Here it is with the engine removed



[edit on 12/22/05 by FredT]

[edit on 12/22/05 by FredT]

[edit on 12/22/05 by FredT]

Nice photos. That looks like it's definitely what it was, then.

By the way, the image chinabean replied to is the one I said appeared normal. It's the OTHER ones that appeared odd to me.

[edit on 22-12-2005 by LoganCale]

Could it maybe be a camera to take photos of the ground or a camera to film what the airplanes seeing, maybe for a movie or something?

Originally posted by Nventual
Could it maybe be a camera to take photos of the ground or a camera to film what the airplanes seeing, maybe for a movie or something?

Please take a look 2 posts up

I reckon it's not an engine, some sort of gadget that has been plumbed directly into the avionics, hence the unusual mounting. An engine test with the engine mounted asymetrically like this would cause stress and load problems all over the ariframe. It could be a "dead" engine undergoing some sort of aerodynamic testing but I would have thought that doing so without the engine in it's natural location would be a waste of time.

It's pretty big, I think it may be a trial at putting radar on commercials or some sort of radar based shenannigans. Possibly some anti-missile technology clumsily applied by a civilian firm undergoing some evaluations...

Just seen the pics above (weren't loading before), this is a new thing to me, but it would seem that these engine tests are the best explanation, such a strange looking test-bed though, nice work on your quick photography. I'd also agree that the contrails seemed to be affected by the wind. I love the ATS forums, big respect to all you guys, you really make it your business to both raise issues and inform. Thanks for all your research efforts, they're a pleasure to read.

Originally posted by Eddie Peoples
An engine test with the engine mounted asymetrically like this would cause stress and load problems all over the ariframe. It could be a "dead" engine undergoing some sort of aerodynamic testing but I would have thought that doing so without the engine in it's natural location would be a waste of time.

Not so. I agree that the thrust in question would be asymetricle, but information about specific fuel burn in different conditions, as well as thrust under load and flight conditions would be better evaluatuated. Also the extra engine can be trimmed out and/or thrust reduced on the engines on the otherside to compensate for the additional thrust. Also, it would allow testing of smaller engines as well as easier adapatation and quicker testing etc.

I would say FredT nailed it - great post Fred!

They could be testing to see how an engine/aircraft performs mounted near the front of an aircraft instead of mid-way or at the rear.

Or it could be a MEPS Multi-megawatt Electrical Power System. Basically the air goes in, spins the blades really fast, and that creates a bunch of power for the aircraft's different systems.

[edit on 23-12-2005 by NWguy83]

Originally posted by LoganCale
Well, it was flying in an east-west loop, with the westernmost part of the loop in the area of Fort Huachuca.

Thanks, that explains what i've been hearing. I'll try to spot it.

Originally posted by bmdefiant
Man im just laughing about the floor imagining a 747 dumping several tons of slurry on an unsuspecting foe...must be an advanced non-lethal weapon system to be used in Iraq

Local pilots familiar with tankers who have witnessed drops described a line of red rain for miles. If such a system was used as a non-lethal weapon it would make sense to load it with some sort of glue. Just imagine laying a swath of sticky goo that gums up everything.

I like the idea of the electrical wind driven generator, I think I will go with that as my answer as well, solves all the thrust related problems in the installation. And gives a reason why this is not being tested in a wind tunnel as you could simulate all the flight dynamics on a live running engine in a wind tunnel.

So my guess is that the real secret is the Honeywell Avionics package being tested INSIDE that paticular 707 then the fact that they are using an external power generator.

Edit, I think the application could be something like a low orbit space plane, that as the plane decsends down into the atmosphere this generator is opened up which produces enough electrical power to run all the systems prior to landing, thereby reducing the battery load needed to make this bird operational.

Or it could even be a spaced launched UASC - Unmanned Automatic Space Combat plane. Could be attached to some orbital weapon platform and dropped into the atmosphere, where a small amount of battery power is needed for guidance and communication, then as it drops in the generator charges up enough stored energy to operate some sort of energy disruption device either EMP beam weapon or high power microwave jammer/fryer etc. Since they are working on that currently for the B1. Maybe this will be an add on pod to the B1 to operate the EMP weapon.....



[edit on 23-12-2005 by robertfenix]

Originally posted by FredT
Its an engine that is undergoing testing. Locheeds L1011 had the capacity to carry a third engine on the wing to ferry it to another location.

Waynos, perhaps this is the location they chose as the engine is pretty small and perhaps the 707 needed the thrust of its main engines to get off the ground??

It sounds logical, but why to use large 707 for so small engine?

Originally posted by FredT
How else would you test one? In your picture the engine that replaced the usual engine was of a higher thrust class than the one it replaced. However, if you want to test a smaller engine you may have trouble getting off the ground given the reduced and asymetrical thrust.

Also mounting an engine in that manner should prove to be no problem esp if its a dedicated test bed. Here is a picture of a 707 with a PW150 turboprop in the front:

FAR/JAR regulations deal with engine out take-offs, all commerical aircraft need to be able to complete a take-off even if an engine breaks at the worst possible time (when the pilot commits to the take-off and cannot abort Vc or something I think the pilots call it) - it shouldn't be a problem for a 707 to take off on 3 engines.


I don't see the point of doing it that way though:

1 - replumb the aircraft
2 - redesign and rebuild the fuselage ribs/stringers to take the different loads
3 - mount the engine in a location that needs special equipment to gain access to (why not mount it near the ground?)
4 - operate the engine in a location it will not be used in, different exhaust airflow conditions, admittedly the nacelle/pylon probably wouldn not have been tailored to the wing of the 707, so it wouldn't be exact anyway. But acoustic evaluation would be useless as there is no wing present.

One more thing - does anyone else think the fan disk is awfully far back down the duct? (See FredT's excellent head on shot )

For an engine that would represent a problem in ensuring even flow onto the fan disk at rising angles of attack.


The nacelle does look a little like the NASA AST one, but I dunno if Honeywell were in on that project - I thought it was with Boeing and P&W.

[edit on 23-12-2005 by kilcoo316]

[edit on 23-12-2005 by kilcoo316]

AOA I think is not an issue, if that was the case the F117 would not get enough air.

Forward velocity is forward velocity regardless of your AOA so your movement vector is still "forward".

Plus AOA angle of attack is the amount of bank plus yaw. The aircraft is still flying forward just in a new direction.

No, duct and external aerodynamics are different, the fan will 'suck' air into the duct, however, the boundary layer within the duct itself can be a problem, and higher pressure gradients resulting from adverse AoAs can be a problem. It can result in non uniform loadings on the fan blades.

For the AoA, you cannot decouple the forward velocity from the vertical velocity like that, pressure gradients tend to ignore ya


I guess with modern design techniques it wouldn't be a insurmountable issue, but it would mean a thicker nacelle wall than I'd guess was optimum, thus increasing drag more than needed. The advantage would be reduced acoustic emissions from the inlet, in conjunction with the full length duct it could well be a design aimed at low noise turbofans (would be in-line with the AST project too).



I'm still at a loss as to why they would mount it where they did though - although if the right engines were turned off, the test design (if it is an engine) would be shielded from the left engines so it could be a reason. However, there is no wing to reflect noise down to the ground - which is a big factor.