V-22 Osprey Tiltrotor

. . ."let the pilot control the guns. . ."
What are you mad!!!
That's insane! He has enough to do without trying to hit something with a weapon. Besides giving the guns to the enlisted guy gives him an instant scapegoat. . .

Don

Yeah i guess they'll have to wait for a virtual targeting system to be perfected.That way they would have a veiw of the whole enviorment around the aircraft.That way they could have a weapon on the top of the craft if needed also.

squidsson - you're close, but I think you overshot a bit (no pun intended)... users of the Apache-style helmets need a lot of visibility... that's going to be tough for a gunner riding in the back... let the pilots control the guns.

If they begin to suffer sensory overload, gunner in the back would be the approach, though he'll probably end up with a CCTV system. Extra electronics and weight factors are concerns, but if it proves to be valuable enough, I think they'd make the tradeoff.

I was wondering about the Apache cannons myself.They could have a couple gunners with the Apache style helmet targeting system connected to a couple of cannons mounted on the bottom of the bird.
Is it just too complicated or is there weight factors involved I wonder?

The location of avionics boxes or other electronics is something I hadn't considered.

I was originally thinking an unmanned Sperry-type ball turret that only has to be partially retracted so that the landing gears have clearance (a la the B-17 or B-24). I don't know the square footage taken up by one of those systems, but having it unmanned would certainly assist in reduction of footprint. Also, if you put it up right behind the cockpit, it would minimize effect on operations in the cabin, much like how a lot of the important lifesaving stuff in ambulances is placed right behind the driver so that it doesn't impede moving the gurneys in and out. On the other hand, a better option may be an Apache-style cannon.

With the number of hydraulic systems going to electronic motors, I'd guess you could probably get a system that cuts into the cabin 1-2 vertical feet, with the housings creating permanent seats/benches (though at the loss of some carrying capacity since they couldn't be folded up like the webbed seats). I'm also guessing there's a gap between the floor and the skin of the fuselage, and taking advantage of it as much as possible would be a better scenario. Ammo could also be run up the walls in conduits (imagine a vertical P-51 wing). But like I said, I hadn't considered how much of this space may already be taken up by black boxes and control lines.

(Oh, and by the way, I'll be graduating soon and don't have a job yet, so if Bell or Boeing or the military wants to hire me to work on this, I can start ~October... e-mail me )

I think the follow question to that would be, what does the turret retract up into? Is there enough room in the airframe for such a device (gun, the mechanics of the lift and ammo) so that it doesn't interfere with the main cabin or cause displacement of any avionic boxes in the cockpit area?

I realize I'm joining the conversation a bit late, with reference to defense issues, does anybody know if a retractable belly turret or two has been considered for weaponry? There'll still be some field of fire issues, but certainly not as many as trying to fire from the fuselage. And if you put it relatively up front just behind the pilots, I don't think it'd obstruct operations in the cabin that much.

QUOTE: Originally posted by salbando Supercobra....hoist ops, rappelling, SPIE/FRIES and drops (squares and rounds) are how we get to where we do our job (except of course for strolling out the door). But hell I thought by your tag you were a Whiskey driver. How did you get the rope time, by starting off in Force Recon?

Nope, long story short I got my ropemaster certification because I was instructing the pilots and thought it would help.

Thanks for the lowdown Don!

The main reason the helo backs off in USCG Rescue Swimmer ops is to get a better view of the situation and to let the swimmer do his job.
Rotor wash is not really an issue when the swimmer is in the water as it has enough resistance to keep you from getting blown away and the mask keeps the spray out of your face.
On cliffs, ice and land however, the rotor wash is bad in a '65 and worse in the '60. On ice you will get blown back a long way. For Ice rescues the swimmer (used to anyway) puts on crimpons to help dig in. Also the helo can go higher than the normal 25 foot approach to a hover to reduce the wash until over the swimmer then decend to a lower altitude.
The wash directly under the helo isn't nearly as bad as just outside the blade path.

Don

Just passing on what i've been told from guys I worked with, and yeah...every helicopter I've ever been under produced varying degrees of rotorwash, but these 3 guys said it was prettty damn bad. Were they able to conduct the testing...yep. But that was even a previously noted problem even form the USMC OT&E side of the house.

Supercobra....hoist ops, rappelling, SPIE/FRIES and drops (squares and rounds) are how we get to where we do our job (except of course for strolling out the door). But hell I thought by your tag you were a Whiskey driver. How did you get the rope time, by starting off in Force Recon?

Here's the bottom line guys...as with any airframe there's going to be folks both pro and con. I'm just saying that from a CSAR perspective (what I do for a living) and one from someone operating in and out of the bird, most of the consent that i've heard is con. I'm leaning that way but then again I haven't worked out of the V-22. I also understand the apprehension when considering change. A new airframe is no different, but I still have to say that given it's troubled past and the comments I've heard from folks involved with OT&E (on the USAF side of the house)...I'm far from sold on the concept for military use in a SOF or CSAR role. The only Marine I talked to about it was a 53 Echo driver (Major) who said that he wanted nothing to do with it. According to him that was pretty much the pulse of the 53 driver community. Now that was back in 1997...has it changed??? Riddle??? The major also said something about RHAW gear/Comm gear interference and something about the co-pilot having problems when making boom contact (during A/R). Something about his view of the probe.
We're supposed to get one up here this October for a Demo during our annual Arctic SAREX. We've been having this exercise for over 10 years now with my unit here in Alaska, the Canadians and the Russians. Each year the location revolves between Alaska, Canada and Russia.

I'll be sure to pass on any observations (both mine and others) and pics if I can remember to take them. Word is we'll also have a CH-149 (EH-101) participating.

I've fastroped/SPIE'd/and rappelled from 53s, 46s, and Hueys, and they are all doable (or we wouldn't do it obviously). I've never gone out of a V-22. Yes they have a lot of downwash but the vector diagrams I've seen show deadzones (or lesser zones) in the right areas and those who have done it say it isn't a problem.

Trigger
I haven't spent any time under a 46 but I was dumb enough to tell some Chinook guys that I would stay and do some hook-ups for them. We had been doing some sling load training on some guys and I drew the short straw. When the 47's showed up I figured that it couldn't be that bad. If they don't make a decent approach it can be pretty rough but all I ever really needed to do was take a knee as they came in. The only really bad part was when the dumb driver cracked my helmet when I got up to do the hook up.

Mac

Thus inspiring challengers to the throne to hock loogs across the land. Just make sure y'all don't spit against the wash.

Here's a great rotorwash story ...

In '69 in Phan Thiet we were hoisting a wounded soldier out of a jungle clearing too small too land in and i was part of the security force surrounding the site. The Huey took very little time getting the litter out and I was standing with my back to it as the rotorwash buffeted everything around. About then, I hocked a big loogie and the rotorwash caught it and carried it hundreds of feet out before it fell to the ground in the trees. I think I set a world record for flipping a lunger.

This isn't a hot rotor, it's a conventional coaxial system like the Russians use a thousand times a day, although it does have some ABS innovations. Sikorsky's ABS testbed used separate, external engines for forward thrust, adding complexity and weight, not to mention fuel consumption. The Rotorjet has the same kind of two-function turbine as a high-bypass turbofan, but the shaft that would drive the big fan drives the rotor instead. And the speed would be decidedly subsonic, due to rotorhead drag, but much faster than Osprey. And much simpler. Fewer moving parts, closer together and balanced in every quadrant around the CG. Sergei had some very good things to say about it. He recommended that the rotor be a low-profile, elastomeric type with a flat chord to reduce drag at higher speeds. And he agreed with me that pitch should be minimal above normal rotary-wing speeds to reduce drag and allow the wings to dominate flight control instead of cyclic and collective, which would be the primary control at low speeds and hover.

I've never been under the rotor wash of anything bigger than a B-412 so my comment about how a tilt-rotor would operate in a maritime rescue situation is based on watching video of Jayhawks and Dolphins conducting pickups.

Hmmm.... Chinooks have bad rotorwash too? Anyone here spent any time under a -46; how's that rotorwash? I'm wondering if the Osprey's rotorwash problem is a problem with the Osprey itself or something that happens with an airframe that has two rotor discs.

Rescue hoist, defensive armament, rotorwash, FRIES... was any of that taken into consideration two decades ago?

The aircraft still has to maintain a hover anytime you're doing hoist ops, FRIES or rappeling. Helocasting is great, but you still need to recover the SAR swimmer.
A while back I spoke to several STS members who (for the USAF) were involved with the OT&E on the V-22. These are guys who've operated out of Hawks, Hueys, Chinooks (probably the worst I've ever dealt with concerning rotorwash). and -53's. These guys said the V-22's rotorwash was the worst they'd ever dealt with. Damn near couldn't stand upright when underneath. Besides, where are you going to mount the hoist?

Now show me a rotorcraft that doesn't produce rotorwash, and I'll give you a dollar. And yeah I've seen lots of brownouts, and whiteouts both here in Alaska and deployed, but for an aircraft that's assuming a mission requiring operators to conduct operations from a hover on a regular basis.....extremely powerful rotorwash is not good.

MBT70
I agree with the others, really great illustration. Interesting concept. Even though it appears to be simple, I've worked on these kinds of things in the past, and it always works out that the devil is in the details. I'm not sure how much speed can be achieved simply because a coaxial rotor system creates plenty of drag. I'm not sure what the state-of-the-art is in stability of high speed rotors, I'd have to do a little research. I don't think it's a simple problem though.

Phil

TRIGGER: The condition you refer to as a brown out is common to all helicopters operated in a dust/dirt filled environment. the solution we found in Viet Nam was to shoot the final approach to the ground, instead of to a hover. It worked out pretty well, plus it had the advantage of providing some modicum of obscuration for assulting troops to dismount our Hueys.

MBT70: Nice design! Looks awsome..however a similar "hot" rotor system as you are proposing was tried on the Sikorsky "X-Wing" and was too complicated to maintain (rotor seals/slip rings were the culprit), they also tried a coaxial helicopter known as the "ABC" (Advancing Blade Concept) in competition to the Bell XV-15 and lost out. Your design looks good! Too bad you weren't around for LHX....

QUOTE: Originally posted by rockythegoat Trigger: If rotor wash is a big problem with the Osprey enough to cause brown outs and what not, as reported, wouldn't it also hinder USCG SAR actvities? I'm thinking if it causes a brown out, then it would stir up water enough to cause similar issues and prevent rescue swimmers from doing their thing.

I think what they do now is, the swimmer goes out the door and then the helo pulls back for that very reason. A tilt rotor would have to do the same.

QUOTE: Originally posted by MBT70 I did it ... that's my Rotorjet concept. You are close ... the rotorhead is coaxial and driven by the jet engine N2 turbine stage. It's an axial-flow jet, not anular flow like jet turbine helicopters, so it produces plenty of thrust. To hover, however, the tail cone slides back and blocks the thrust, also exposing cascades on either side that vector it at 90 degrees right and left, canceling the thrust effect. Movable vents within the cascades vary the side thrust enough to turn the fuselage as needed. Too damn simple, isn't it?

Holy crap, I actually understood most of that, and I'm not an engineer (I suck at math so I changed majors)! I'll have to look up a couple of things tonight when I get home, but yeah, that seems pretty simple.

That's a SWEET illustration. I'd like to see some more and discuss the techniques and materials you illustrate with. Shoot me an e-mail?

Neat design

You mean like this?

Very cool, not that I understand all (or any, for that matter) of the techno-talk about it. I can see the attack/escort possibilities from your picture, would it be scalable up to heavy lift and troop transport? Would that require additional rotors and engines?

I did it ... that's my Rotorjet concept. You are close ... the rotorhead is coaxial and driven by the jet engine N2 turbine stage. It's an axial-flow jet, not anular flow like jet turbine helicopters, so it produces plenty of thrust. To hover, however, the tail cone slides back and blocks the thrust, also exposing cascades on either side that vector it at 90 degrees right and left, canceling the thrust effect. Movable vents within the cascades vary the side thrust enough to turn the fuselage as needed.
Too damn simple, isn't it?

Is that some sort of jet powered autogyro or coaxial?

It's a NICE illustration - who did it?

Wow! Those don't look too far off from my AV-15. Biggest difference is the tandem cockpit.