Robinson R-22 Manifold Pressure Online Ground School
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- เผยแพร่เมื่อ 8 ต.ค. 2015
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Robinson R-22 Training Manifold Pressure Online Ground School. Hey, this is David Redmond, at Odyssey Aeronautics in Auburn, California. We had a member on Helicopter Online Ground School ask about Robinson R-22 manifold pressure and what that means. I'm going to make a little video today on manifold pressure performance, and we're going to take that right into why we have the engine we have in the Robinson R-22 Helicopter. When you're dealing with manifold pressure the first thing you really need to understand is what the heck is it measuring. It's measured in inches of mercury. Most people don't understand what that actually means. Back in the day when they had to measure what is the pressure of the atmosphere ... You know they had to measure this thing. They built a device that looks just like this and they filled it full of mercury. When you see something that says, inches of mercury, Hg is just the 2 letter identifier for mercury on the periodic table. What they did was they pulled a vacuum in this tube and this mercury would get pulled up right here. What's actually going on is it's the outside pressure pushing down that's pushing the mercury up. Well if you pull out all the air so it's a complete vacuum up here this mercury will only rise so far, and then you literally just measure it. If you go outside and it says, oh today is 30 inches of mercury, like your altimeter setting, that literally means that the mercury is getting pulled up 30 inches. If you have a lower pressure system coming in and you don't have nearly as much pressure coming in this level will go down to let's say like 28 inches, or a higher pressure system comes in and you have the mercury go up to let's say 31 inches. It's just literally how high up mercury goes in a tube with a vacuum and an open pool. When they say high, low pressure, inches of mercury, this is what they're talking about. Now on to our manifold pressure gauge. This is just measuring pressure. Now here we have kind of a cartoonish drawing of the engine and we have ... Air would come through here. This is our throttle, so this lets more or less air into the engine. Then it goes from there into the engine. Obviously we have venturi and fuel and all that kind of stuff going on, but for this we're not worried about that. Do you ever notice when you get into the Robinson R-22 helicopter and you haven't started the engine yet, your manifold pressure is up to almost the end of the scale. The manifold pressure will be reading something over here like 30 inches. Well with the engine off, and I just ... This doesn't actually exist, but I just made up my own manifold pressure gauge for on the other side of this butterfly valve. Right now this is all equal. No air is flowing anywhere, so your pressure inside going to the engine is actually the same as your outside atmospheric pressure. You can see these 2 are the same. The engine starts turning over and it starts pulling air in, well this throttle is mostly closed. You're actually going to pull a vacuum in here and this manifold pressure, you'll notice when the engine starts it's going to drop way down. This will drop down to somewhere around 10 to 12 inches at idle. Which means you still have 30 inches of pressure out here in the outside atmosphere. This butterfly valve is mostly, so it's not allowing much air to get by, so you have far less air pressure down here. That's why your manifold pressure is down low when the engine is at idle. Once you start actually flying this valve will start to open up depending on your power needs and let more air through, so your needle will begin to rise reflecting that up to, let's just say like 22 inches or more. This Robinson R-22 manifold pressure is just simply measuring how much air pressure is going into the engine. That's a direct proportional to how much power the engine is producing. As a note, before you start the engine. You're sitting there the engine is dead, wherever this manifold pressure gauge is reading is actually where the engine would be at if you fired it up and ran it wide open throttle. When you do your limit Robinson R-22 manifold pressure checks and you look at your chart and say, okay given this altitude and this temperature I can pull, let's just say 23 inches of power. That 23 inches of power will be back here, but your engine could actually pull this much power. We're just not letting it go wide open throttle.
Excellent tutorial, no music, no drama, just solid information ... I wish others would get the message that all that "foo-foo" junk adds nothing to the instructional value! Thanks.
Awesome thank you!
got an r22 and rebuilding it by myself for decoration. after your videos, i will definately start it up
Have fun!
David Redmond, you've explained and taught me this before going through flight school in such an outstanding way that I could understand it 100% I will for sure be ahead of the game now and I'm sure it has eased things up for me in future teachings of this. I love the analogies. made it very easy to follow and comprehend. Thank you so much brother!
Thanks for commenting! Dave is an awesome instructor! We will have some new videos coming from Dave soon!
Great explanation on manifold pressure and how it applies to flying! I appreciate the lesson...
Thank you for the feedback!
Excellent description of the significance of manifold and atmospheric pressure
Thanks!
Thank you David. Your video is clear, informative and of great value.
Thank you for the feedback!
Absolutely phenomenal explanation and great use of the the white board visuals. Thanks.
Thanks for commenting!
Really enjoyed and more importantly UNDERSTOOD thank you sir. I'm going to use this for my high school class due to your ability to put a complicated concept in a very simple way.
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Crystal clear explanation. Very easy to understand.
Thank you!
Thanks, another excellent video Dave!!
Your welcome and thank you!
Brilliant. Thanks for the fantastic explanation.
Glad it was helpful!
Very good explanation... clear & concise. Thanks!
Thanks for commenting.
Excellent explanation! I have always wondered what manifold pressure is and now, thanks to your lucid lecture, I think I nailed it !
Thanks for the feedback! I would like to give you a free copy of a book I wrote "Helicopter Check-Ride" It hit Amazon #1 best seller within 24hrs of publishing. Here is a link. www.helicopterground.com/pl/1856
Hello. Can u help me about snage
Thank you, your instruction helps 🙏🏼👍🏼
This is a very popular video for us. We have many more like it in our online courses at www.helicopterground.com/
Thanks for watching and commenting. We would like to give you a free PDF copy of an Amazon #1 best selling book, "Top Ten Check Ride Tips". Here is the link for the free book www.helicopterground.com/pl/38587
ugh... GOLDEN - thank you!!
Thanks for commenting.
Great job on the explanation.
I had an old army maintenance pilot once say that the term "de-rated" was probably the cause of the confusion. He liked to explain this same theory, except he used the term "reserve engine power" needed for higher altitudes. Since the "De-rated" term has become the language we use when teaching, the law of primacy makes it hard for us to change.
I notice that you use both the Robbie & Enstrom when posting these videos.
If you add the explanation of how the turbo charger (like the one on the
Enstrom) effects the manifold pressure, it might be helpful for your Enstrom students too.
Thanks for the feedback!
Brilliant explanation thank you 🙏
Thanks for the feedback!
Wow....well explained!!
Thank you 🙂
Great video - just about to start rotary lessons on the R22 this helps, thank you,
+sheffair1 Your Welcome and Thank You sheffair1!
Thank you David that helps a lot! Couldn't understand how MP works 🙏🏼👍🏼
Thanks for the feedback!
very very..very..well explained . well done 🙂
Thanks Gabriel. Grab a free copy of Amazon #1 best seller, "Helicopter Check Ride". You will have to enter an email for the free digital download, but we do not share your email! www.helicopterground.com/pl/1856
Excellent and professional explanation. Fortunately no music
Thank you very much!
Another outstanding explanation! I'm currently working on my CFII and wish you the best of luck in your career. Hope to cross paths out there one of these days. 👍🏻
Thank you! It's a small world may very well happen!
Thanks for teaching this
Thank You!
Good job !! 👍
Thank you! Cheers!
What an awesome video, perfect explanation
Glad you like it and thanks for commenting.
@@HelicopterGround can help me pls
Thank you
You're welcome thank you!
Hi. Had my first helicopter ride this past weekend in a R-44 Raven II. Very exciting.
You presented a good explanation and I learned how the chart helps identify power. But one caveat; always describe the pressure of air as a "pushing force," not as a vacuum. Nature seeks to fill a vacuum all the time and vacuums do not draw/suck air. So when barometric pressure drops from 30" Hg to 28" the air pressure is lower and doesn't seek to fill the vacuum as quickly, thus the HP loss. Same thing in a car engine. Thanks! :D
Glad you liked the R-44!
Auburn CA my hometown!, greetings from Helipro in San Luis Obispo, CA
Cool Mitch. I see you tested out the instrument course last fall. Did you get your instrument rating?
I sure did, II too thanks so much for all the great material!
Very nice, and thanks for the reply and positive feedback!
A+ explanation
We get that alot :) Thank you! Grab a free copy of Amazon #1 best seller, "Helicopter Check Ride". You will have to enter an email for the free digital download, but we do not share your email! www.helicopterground.com/pl/1856
Excellent!! *gitar riff*
Thanks
Ballin video!
+Daniel Vazquez Thank you very much!
Thanks !! nice explanation
Thanks Natalie. Are you training in the R-22? We would love to give you a free copy of "Helicopter Check Ride". This is Kenny's first book that hit Amazon #1 best seller. Here is the link and don't worry, we never share emails! www.helicopterground.com/pl/1856
Yeah I have my private and I doing my commercial now I'm confused with MP when used with different wastgates in turbocharger (for an unknown reason) ^^ getting there eventually
I see. MP is a different topic when moving from a non turbo to a turbo. A non turbo always has a vacuum when running because the engine is sucking the air in, while a turbo builds pressure greater than the daily barametric pressure when running because the air is being forced in with a fan driven mechanically from another fan in the exhause flow. The manufacture sets the limits on both based on their research. A waste gate set up would definately have a great deal to do with their magic number to limit you on a turbo. Feel free to browse our free video blogs at www.helicopterground.com/blog
Great! Thanks 😊👍🏽
Thanks for commenting Mona!
👏🏾👏🏾👏🏾 Parabéns 🇧🇷
Thanks for commenting
Great job. In addition, engines, whether its piston or turbine are de-rated to so that the engine will make TBO. The hover charts are just references if you try to hover beyond the reference point you can experience low rotor rpm. I tell my students to rename the charts "low rotor charts". Some older engines don't get anywhere near the references on the chart. So be careful especially at higher altitudes where the chart says you can do it, yet the LR horn is blaring in a hover.
Thanks for the info!
The manifold pressure like the oil pressure should be monitored and handled with automation since the pilot has enough on his plate just flying the helicopter and only if there is a problem or potential danger should the pilot be alerted by a warning light and sound. The helicopter can also be designed to prevent the pilot from exceeding design tolerances during flight to prevent accidents.
Thanks for commenting
amen brother
Thanks for commenting
Can you do a nuts and bolts explanation
video on how to basically manage that
manifold pressure, examples, what to
watch for, what to watch out for. I hear
about this constantly with airplanes but
no one seems to go into the practical
does and don'ts and examples of controls
and what you actually twist turn etc, to balance
out manifold pressure against 'whatever' else.
We cover that inside www.HelicopterGround.com
@@HelicopterGround
:facepalm:
can someone explain why in the maximum continuous power chart the manifold pressure drops with altitude but rises with temperature ?
th-cam.com/video/v5-Dt18v2VU/w-d-xo.html
one question: Why do yo not use a pressurized motor? Such a motor has a much lower derating in high altitude and
is also much lighter in weight. For example the pressurized Rotax-Motor gives also about 125 hp.
We use what the manufacturer designed.
@@HelicopterGround sorry... I supposed you are the manufacturer..
4:10 why aren't we letting it pull full power? Because RHC uses lighter materials in the engine so with too much air/fuel entering ilthe engine would wear out faster than is safe with our inspection intervals?
Thanks for commenting.
How can the MAP chart be indicating 124 hp throughout if the power they tell you to pull gets lower and lower? In your example, you indicated you would have to pull the same HP at elevation to get the same HP.
I believe you are forgetting the lapse rate. I reviewed the video again carefully and it is 100% accurate. For more r22 videos, check out my site at www.helicopterground.com and check out my newsroom for free. It has a ton of video blogs in it for absolutely free. Here is an easy link www.helicopterground.com/blog
Hi (Kenny?), thanks for your response. I actually have the lifetime membership on HOGS. Let me be more specific about what I'm confused on:
In the video it's stated that at 24 inches at sea level, the derated engine is producing 124 HP. Then, it's stated that at 3000 feet, the derated engine is still at 24 inches (with some reserve left over), and still producing the same amount of horsepower - that horsepower would only decrease if the inches pulled had to also decrease.
So if the MAP chart is indicating 124 hp throughout the chart, why does the inches you need to pull to get 124 hp go progressively lower with altitude, although in the example in the video you stated that you pull the same number of inches to maintain the same horsepower at higher altitude?
I believe the illustration is confusing you. Think of it this way, barometric pressure decreases as you climb. At some point you will be full throttle, only to achieve the same manifold pressure and horsepower as you had in a ground effect hover. When the non-turbo aircraft reaches full throttle, the manifold pressure and the outside barometric pressure are equal. Butterfly fully open, cannot increase from there. If you continued to climb, you would run out of power
So the pilot via the POH derates the engine?
Essentially
helloooo
Hello!
tengo un MAP de 12.5" en bajas y en alta 14" colectivo abajo.R44 .cual es el Map ideal en alta please?..
English please?
@@HelicopterGround my cuestión is in the R44 have a Manifold.pressure12 .5hg in low collective down idle and 14.5 hg in up.my cuestión is that correct.?...
First FU the inventor of all this.
Second of all the thoings that will kill, a slight math miscalculation, and next is your helo is settling into fatal terrain and there is nothing you can do about it, except pushing your passenger out and dropping slung load, if any.
Thanks for commenting
Brilliant. Thanks for the great explanation.
My pleasure!
Thank you
Thank you!