Armed Polite Society
Main Forums => The Roundtable => Topic started by: 230RN on August 08, 2023, 02:53:27 PM
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Browsing around on helicopters and I sometimes wonder how in the hell they ever got developed to the point where they actually got practical.
https://youtu.be/YT39Qor9Ty0 (3:06)
Bell 47 (1941), the "M*A*S*H model."
I suppose my doubts are because all the linkages and swash plates and connections to the tail rotors are pretty much visible to the naked eye, instead of being covered up by a sleek faired body. And man, all those variable forces on that central rotor shaft ! Yikes.
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https://www.youtube.com/watch?v=AnHmEs3TOq4
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The idea of vertical take off was enticing enough for folks to keep throwing money at Igor Sikorsky until he figured it out.
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I also discovered that one of the Batcopters, N3079G, was a Bell 47.
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2F13thdimension.com%2Fwp-content%2Fuploads%2F2014%2F01%2Fbatcopter.jpg&hash=7b9bb3056a17d6a7a9394f1548b86dadcfeb46ad)
Also N937B, in TV's "Highway Patrol," 10-4.
(https://c8.alamy.com/comp/BK0MTJ/highway-patrol-us-ziv-tv-series-1955-59-with-broderick-crawford-as-BK0MTJ.jpg)
I always laughed at Broderick Crawford's ability to down a bad guy at 100 yards with his little old snubby and snap shooting. And keep his hat on.
You know, I think we have an unsung unOscared movie star in the Bell 47.
Terry, 230RN
Pic credits in Properties
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That reminds me, I've still got the plans for a home-built, including prop, helicopter using a motorcycle engine.
Not sure that's ever gonna be built....
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That must be one "heck" of a motorcycle motor to power even a single seat chopper. =|
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IIRC, the plans call for a 650cc.
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That must be one "heck" of a motorcycle motor to power even a single seat chopper. =|
Early versions of the Bell 47 had a 157hp motor. Well within range of many modern motorcycle motors
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Wiki, 47 helicopter:
"Engines were Franklin or Lycoming vertically mounted piston engines of 178 to 305 HP (150 to 230 kW )."
That's for a full 47, max takeoff weight 2850 lbs with a 265 HP engine
https://www.flugzeuginfo.net/acdata_php/acdata_47_en.php
Just for grins, call it 10-11 lb per HP or a tenth of a HP per pound. Just for spitballing purposes with a well-engineered highly successful chopper.
(Composed and posted before seeing WLJ's post. Man, he's fast.)
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I bet that is a Gyrocopter and not a true helicopter @Cliffh.
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I always laughed at Broderick Crawford's ability to down a bad guy at 100 yards with his little old snubby and snap shooting. And keep his hat on.
Apparently the pilot does all the aiming. All he had to do was keep his hat on and pull the trigger.
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I thought I heard someone say what made them really practical was when they started using turbine engines. Gave them a lot more power.
One of my material science professors talked about using composites for the rotors and setting it up so if the rotor started to crack or fail, you had some warning and it didn't immediately break off causing a crash. That was in the early 1990's so I have no idea when that work was done.
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I thought I heard someone say what made them really practical was when they started using turbine engines. Gave them a lot more power.
And reliability, which can't be over looked especially in helicopters
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I bet that is a Gyrocopter and not a true helicopter @Cliffh.
The plans show one overhead prop & a tail rotor w/skids, no wheels/tires.
It is, of course, supposed to be an ultra-light.
Keep in mind I bought these plans about 30 years ago.
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The plans show one overhead prop & a tail rotor w/skids, no wheels/tires.
It is, of course, supposed to be an ultra-light.
Keep in mind I bought these plans about 30 years ago.
Ahhhh! When you said "prop" I thought propeller, not a "Rotor Blade". My bad.
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I thought I heard someone say what made them really practical was when they started using turbine engines. Gave them a lot more power.
One of my material science professors talked about using composites for the rotors and setting it up so if the rotor started to crack or fail, you had some warning and it didn't immediately break off causing a crash. That was in the early 1990's so I have no idea when that work was done.
Like the early warning system on the Titan submersible?
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Warning. One of your rotor blades is about to fall o
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Wiki, 47 helicopter:
"Engines were Franklin or Lycoming vertically mounted piston engines of 178 to 305 HP (150 to 230 kW )."
That's for a full 47, max takeoff weight 2850 lbs with a 265 HP engine
https://www.flugzeuginfo.net/acdata_php/acdata_47_en.php
Just for grins, call it 10-11 lb per HP or a tenth of a HP per pound. Just for spitballing purposes with a well-engineered highly successful chopper.
(Composed and posted before seeing WLJ's post. Man, he's fast.)
Bell heli engines were used in cars, too. (Well . . . maybe one car model. With very limited production.)
"For the production models, engineers selected the O-355, made by Air Cooled Motors, it was used in many small aircraft and made for the Bell 47 helicopter. It produced 166 horsepower. Engineers modified this engine to be used in a car and water-cooled it for some reason. Preston Tucker liked these engines so much that he bought the engine company."
https://www.hotcars.com/tucker-torpedo-facts/#it-was-powered-by-an-aircraft-engine
https://en.wikipedia.org/wiki/Franklin_Engine_Company
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I thought I heard someone say what made them really practical was when they started using turbine engines. Gave them a lot more power.
One of my material science professors talked about using composites for the rotors and setting it up so if the rotor started to crack or fail, you had some warning and it didn't immediately break off causing a crash. That was in the early 1990's so I have no idea when that work was done.
Turbines sure helped but consider the H-34. Vietnam pilots loved that thing because they sat over the large radial engine that absorbed a lot of ground fire.
Lots of systems have a pressurized hollow spar on the blade and an indicator of pressure loss. My old helo was a static visual indicator but later evolved so that when one popped a little radioactive source was exposed to the sensor that picked it up when flying.
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Turbines sure helped but consider the H-34. Vietnam pilots loved that thing because they sat over the large radial engine that absorbed a lot of ground fire.
Lots of systems have a pressurized hollow spar on the blade and an indicator of pressure loss. My old helo was a static visual indicator but later evolved so that when one popped a little radioactive source was exposed to the sensor that picked it up when flying.
Boy, that sounds Rube Goldbergish. Was that radioactive source by any chance a phosphor-tritium light source, as in tritium gun sights?
I never really thought about it before, but those blades really go through hell, and early warning methods are a good idea:
https://newatlas.com/aircraft/bladesense-helicopter-rotor-blade-monitoring-system/
Dramamine™ special (slo mo camera on rotor hub):
https://youtu.be/gxbAoQW7cgg (1:12)
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Like the early warning system on the Titan submersible?
The way he described it, the composite would use long fibers lengthwise that were much stronger than the matrix material. So if the composite cracked through, the fibers would hold on and keep the rotor from coming apart and unbalancing the whole system. I think the idea was to turn a hard crash into an emergency landing. Like I said, this was 30 years ago when I heard the story so I don't know if anything like that is used now.
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Integrated Blade Inspection System used Strontium-90 for a source. I remember them so well because I cut the crap out of my hand on one when a wrench slipped.
I miss my time working on helos but ones today seem too boring to go back to. I was on some of the last great mechanical beasts, H-3s or S-61 in civvie trim.