The Boeing-Vertol BV-347 - Basically a Chinook with wings!

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BrtFrkwr@reddit

Good wiki entry https://en.wikipedia.org/wiki/Boeing_Vertol_BV-347

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waldo--pepper@reddit

" During demonstrations in Washington DC, the BV-347 was flown by over 125 pilots, 100 of which had never flown an aircraft of any kind before, with some even being capable of performing normally difficult maneuvers.

Never flown ... well golly!

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ackermann@reddit

What about this design made it so easy to fly? Do the wings add stability somehow?

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Massive surplus of lift when not loaded, no tail rotor to worry about, and a ton of mass to dampen out wind and whatnot. I had a buddy I used to work with, who was primarily an Apache pilot, but managed to fly damn near every airframe the Army operated. He always raved about how nice the Chinook was to fly.

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Mediocre_Dog_8829@reddit

A Chinook and an Apache landed near me recently. I was surprised to see that the Apache is almost as long as the Chinook. Roughly 15 metres vs approx 16 metres, if my memory of what I read in Wikipedia is accurate.

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rocket_randall@reddit

Lift, mostly. I have never flown a Chinook, but pilots have said that it's a bit more intuitive than other helicopters since the rotors are synchronized and you can change power without having to engage the pedals to offset yaw. This model also had the automatic flight control system which was incorporated into the D model, which further assisted the pilot.

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RCAF_vet71@reddit

If the rotors were not synchronized, they would quickly chew each other to bits on start. I think you mean to say that they are counter rotating and therefore cancel out the torque that a single rotor helicopter experiences, which in turn requires the tail rotor.

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aadoqee@reddit

I would say the fly-by-wire system is responsible

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rocket_randall@reddit

Vietnam era rotary aviation had its moments.

The pilots then offered to "put on a little air show." They proceeded to do low hovers, high hovers, pedal turns, sideways and backwards flights, nothing particularly fancy or dangerous. That ended the demonstration. The pilots had two hours of fuel, and were just going to "burn it off on the back 40" when the pilot radioed the DZSO: "Hey, any of your guys want to get some stick time?" We couldn't believe it. The pilot was willing to let the Pathfinders, none of whom were rated aviators, fly the helicopter. We had heard apocryphal stories of aviators in Viet Nam who had taught their crew chiefs to fly in case the pilots were shot on an LZ and unable to take off. It was considered a form of life insurance. Based on the offer from this pilot, apparently those stories were true.

2LT William Groce was first to leap at the offer. He asked: "Who wants to drive my 'vette back?" [from the DZ]. CPT Dougherty, who loved Corvettes, agreed to drive it back. SSG Tichenor had left his car at the airfield, so he stayed with the helicopter. I asked, "Who wants to take the roller skate back?" but got no offers. So we watched as the pilot got out of the cockpit of the helicopter and climbed into the back cargo compartment, while 2LT William Groce got in the pilot's seat and strapped in. They took off, in what appeared to be a regular takeoff. We watched and waved as they turned west and climbed to a few hundred feet. I said to myself "That lucky son of a bitch." Then the main rotor head snapped off.

http://airassault.bizhosting.com/PostRVN.htm

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sidneylopsides@reddit

"In a fraction of a second the mast is overloaded and it snaps. In this case the blade pivoted down and sliced through the left side of the cockpit after breaking off. The blade was recovered several hundred meters away. Embossed in the leading edge, in reverse type, was the word "BELL". This matched the raised lettering on the co-pilot's anti-torque foot pedals of the Huey, destroyed when the blade sliced through and struck them."

Wow

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rodface@reddit

That is a dark story. I like seeing this sort of writing out there, real history.

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Mal-De-Terre@reddit

Sorta begs the question of why they're called pilots, then

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Constant-Draw2629@reddit

Im surprised it didnt get more widely adopted

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Xav_NZ@reddit

This thing had FLY BY WIRE in 1970 in a HELICOPTER that is insane ! apparently the very first helicopter to have FBW.

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CountGrimthorpe@reddit

It's almost the first aircraft period to fly with digital fly-by-wire (analog systems predate it by a lot). There was a NASA F-8 with an Apollo guidance computer that beat it out, but that's assuming the 347 didn't have the FBW system in its first test flights. I did a little looking to see when the prototype had its FBW system installed, but there's not a lot out there.

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Xav_NZ@reddit

I was about to mention the Space Shuttle in my original comment but STS1 launched in 1981 so technically this either predates or is roughly at the same time. Pretty insane either way.

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Gramerdim@reddit

ok but why and how?

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Agitated_Art7@reddit

B

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Latentius@reddit

The wings are, of course, the primary weird feature of this aircraft, but just in case that weren't enough, they added an extra blade to each rotor.

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Raaka-Kake@reddit

Any idea why they added the extra blade?

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Latentius@reddit

I would expect extra lift would be a primary factor, but a quick search says it was also an attempt to reduce noise by splitting the same load across more blades.

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WholeLottaBRRRT@reddit

It looks like they’ve took the wings from an F-8 Crusader or A-7 Corsair

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Correct_Inspection25@reddit

The USSR Mi series had a number of models that could achieve up to 20% of their crushing lift with wings, this made sense. Guessing the mass of the wing didn’t offset the lift gain.

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earl_of_lemonparty@reddit

The Mi-24 produces 28% of it's lift from it's fixed wings:

https://www.globalsecurity.org/military/world/russia/mi-24-design.htm

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R-27ET@reddit

The lift gain does offset the mass by quite a lot.

The main problem with the wings on Mi-6/24 is that the rotor wash pushed against them in a hover, reducing max hover takeoff weight.

Little problem for Mi-24, bigger problem for Mi-6.

Mi-6 could even rotate the wings down to stop them stalling during autorotation, which is another weakness.

For Mi-6/24, the benefit was from cruise/climbing/turning from ETL to max speed, actually reducing Retreating blade stall becuase by being position behind the rotor/CG they reduced the need for forward cyclic (which decreases speed of retreating blade stall), and increased pilot comfort and also acted as a stabilizer.

On Mi-35M with shortened wing, one of the main complaints was pilots was it made it less stable at cruise speeds.

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dmr11@reddit

The main problem with the wings on Mi-6/24 is that the rotor wash pushed against them in a hover, reducing max hover takeoff weight.

BV-347 fixes that problem by rotating the wing to point up during hover, as seen in the third picture of the post.

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Correct_Inspection25@reddit

Thank you! I only recently learned about that feature, and wondered why the US didn’t have that featured more prominently. Like i thought the Navy heavies sponsons provided some lift but found out that effect was negligible.

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BrtFrkwr@reddit

What the wing does is partially unload the rotors allowing the aircraft to fly faster and more efficiently.

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Correct_Inspection25@reddit

Didn't even think of that bonus, longer serviceable rotor lifespan.

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Foreign_Athlete_7693@reddit

Now this is the sorta plane I wish someone would add to the FlightGear repository😂

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Havoccity@reddit

Looks and is named like something made by Blohm & Voss

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Constant-Draw2629@reddit

I wonder why it isn’t more popular

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_BMS@reddit

It's kinda hard to visit. It's located at the Army Aviation Museum at Fort Rucker, meaning you need to either have a military ID or get a visitor's pass to get on the installation to visit.

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Vast-Return-7197@reddit

Well damn, tilt wings.

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CarVac@reddit

Tilt wing but fixed rotor.

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brumbarosso@reddit

Chinook be wildin sometimes

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bCup83@reddit

Oh god no! Dear god no no! 😱

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PlanterDezNuts@reddit

I am a pilot who has also never flown any other type of aircraft

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tuckernielson@reddit

I love this sub - I’ve never seen this before. Thanks for sharing.

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CapitanianExtinction@reddit

What do the wings do?

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RonaldMcDnald@reddit (OP)

They were added to provide extra lift and maneuverability during flight, and even cooler, they could rotate 85 degrees upward to minimize rotor downwash during hovers

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Double_Minimum@reddit

Provide lift when moving forwards? Which likely increases fuel capacity, so extra distance, or if that isn’t needed, possibly extra cargo instead of the fuel weight.

One the fastest helicopters in the world has wings (single “post” counter rotating rotors and a pusher prop).

Not having a tail rotor can make a helipad design wild