Jump to content

R22 de-rated?


Recommended Posts

I think I only have a vague understanding of the R22 being de-rated. Can anyone explain this and WHY they would de-rate the engine?

 

 

Thanks.

 

Hey, I'm just starting my PPL ground school, but I'll take a shot at answering this (all you old grizzled pilots go easy on me if I get it wrong please).

 

From what I understood from our first lesson, the R-22 only weighs 865lbs and the Lycoming powerplant was derated in order to increase the longevity of the powerplant, since the R-22 doesn't require the full HP of the engine (180 maxhp) to achieve lift when fully loaded.

 

Like I said, I've only been through the first week of ground school so, if I've misunderstood, I would definitely appreciate clarification or more details.

 

Kelly

Link to comment
Share on other sites

Hey, I'm just starting my PPL ground school, but I'll take a shot at answering this (all you old grizzled pilots go easy on me if I get it wrong please).

 

From what I understood from our first lesson, the R-22 only weighs 865lbs and the Lycoming powerplant was derated in order to increase the longevity of the powerplant, since the R-22 doesn't require the full HP of the engine (180 maxhp) to achieve lift when fully loaded.

 

Like I said, I've only been through the first week of ground school so, if I've misunderstood, I would definitely appreciate clarification or more details.

 

Kelly

 

Yes, this is correct. However, it is also derated to allow for better altitude performance. As you go up in altitude, you lose available horsepower. If you start at 180 HP instead of 131 HP, you can maintain maximum usable horsepower to a much higher altitude.

 

Another added benefit is you have a great deal of reserve power to use in an emergency. If you need to pull 180 HP at sea level to keep from bending metal, then go ahead. It won't hurt anything.

 

One final reason is that lowering the RPM slightly reduces noise.

Link to comment
Share on other sites

What the others are saying is true. From what I got from my instructor and from attending the safety course, derating the engine

 

Protects the drivetrain from handling more than they are designed to.

Extends the life of the engine to 2200 hrs.

Allows for a higher density altitude and reserve power at the higher altitudes

Link to comment
Share on other sites

Cool, I had read a bit about the better performance at higher DA from somewhere (this forum) but didn't want to just spout that out since we didn't really cover it in our class last week. Good to get the fuller explanation.

 

Thanks!

Kelly

Link to comment
Share on other sites

Hah. Well I am always thinking of Frank as a great engineer and an even better businessman, so if you think of it in terms of what he wants for his product, it all makes sense. The product can mechanically perform much more than it is RATED for, saves him the trouble of people bending them up all the time (bad for business, esp if you happen to also own the insurance company... B) ...) because there is always some reserve power "in the bank".

 

But the way it is usually explained is that it by limiting the performance to only a percentage of it's max potential, it "preserves the mechanical and structural integrity of the engine" (since it's the engine that's technically de-rated but that obviously helps save wear and tear on the rest of the powerplant)...so it can get to 2200hrs. Basically another way of saying what everyone else has already said! :P

Link to comment
Share on other sites

For the sake of clarity I'll compare the R-22 Beta and Beta II because these are the only two helicopters I know how to fly and, as far as I know, the only one's derated (I don't know if Schweizer derates their helicopters).

 

Schweizer derates the 300C, they don't clearly say so in the manual, but it is derated. The 269A, 269B, 300CB, and 300CBi are not derated.

Link to comment
Share on other sites

If you need to pull 180 HP at sea level to keep from bending metal, then go ahead. It won't hurt anything.

 

 

Rocky- be careful here. The R22 is one very light weight ship because the components are built light weight and designed to take 131 HP not 180 HP. You can take out the main or T/R transmissions, bearings, mast stresses, etc, if you pull 180 HP when those components are designed for much less. Of course, you probably won't be flying it when it fails, because these stresses are cumulative in nature...so some poor skinny guy will be in the ship when it falls from the sky. However, I agree that if you need to pull the power to keep from bending metal then do so....just report the excessive MP so that your mechanic can can check the ship before the skinny guy gets in.

Fly Safe !

Goldy

Link to comment
Share on other sites

Yes, this is correct. However, it is also derated to allow for better altitude performance. As you go up in altitude, you lose available horsepower. If you start at 180 HP instead of 131 HP, you can maintain maximum usable horsepower to a much higher altitude.

 

Another added benefit is you have a great deal of reserve power to use in an emergency. If you need to pull 180 HP at sea level to keep from bending metal, then go ahead. It won't hurt anything.

 

One final reason is that lowering the RPM slightly reduces noise.

 

What do you mean by "lowering the RPM slightly reduces noise." ?... The derating isn't from the reduction in RPM, and Engine/Rotor RPM is almost entirely constant in powered flight. You completely lost me on that statement.

Link to comment
Share on other sites

Hey, I'm wondering, if you pull an inch over the 5 min max power, will that do much-if any-damage. I'm looking for actual instances, not theory.

 

Thoughts?

 

Later

 

Hey Aaron, where ya been?

Link to comment
Share on other sites

Schweizer derates the 300C, they don't clearly say so in the manual, but it is derated. The 269A, 269B, 300CB, and 300CBi are not derated.

 

The 269B is "derated" in the same way the 300C is.... The B model is limited to 26.1 inches manifold at sea level and can maintain take-off 5 minute power up to 3900 feet (180 hp) and max continuous (160hp) up to 7200 feet.

 

The C model is 26 inches (standard atmosphere) up to 4200 feet (190 hp) and there is no 5 min. rating or take off rating... all power (up to 26 inches) can be used at all times.

 

The A models still have the 180 hp max power 5 minute rating but can use as much manifold as available (engine is 180 hp).. max continuous is 160 hp (26.2 inches)

 

I know we've been over the "derated" topic before but wanted to clarify the 300's

Link to comment
Share on other sites

Hey, I'm wondering, if you pull an inch over the 5 min max power, will that do much-if any-damage. I'm looking for actual instances, not theory.

 

Thoughts?

 

Later

 

Hey Aaron, where ya been?

 

 

I will go on the record and say that if you pull ONE inch over 5 min. max you will not do any damage..... The variables in deducing ACTUAL power being distributed to the drive train will vary by engine compression, and a whole slew of other factors...... the manufacturer has tested the components to well over their design continuous rating and it will not come apart or damage anything ONE inch over published.... (you may cause additional wear).... but as stated above, that one inch on one engine may be less power than the published power output for the helicopter (131 hp or whatever it is).

 

note: everything stated in this post is my personal opinion and should not be used as justification to depart from the published poh.

Link to comment
Share on other sites

If you pull over the rated power, you're putting more strain on the transmissions and rotorhead than they were designed to take.

 

Will it come apart in 2 seconds? No, of course not. It will have a reduced life because of it. Do it a few times over the 2,200 hours of a Robbie and it shouldn't come to any harm. Do it every flight and you are a lot less likely to have 2,200 successful hours of flight time before something comes apart.

 

There is no inspection (that I've found) for going over max rated power, however it is unwise to do it on a regular basis. Take care of your helicopter and it will take care of you...

 

Fly Safe!

Link to comment
Share on other sites

Let me ask a stupid question. When I was doing my Army training in the TH-67 (bell 206) we pumped out a PPC (performance planning card) everyday where we figured out our max torque, cruise torque, etc for the day... We, based on that card would know if it were a engine or a transmission limit... Does the civilian world, either the r22 or 300 have anything like that? To tell you that you would hit an engine limit or transmission limit first for that day?? Thanks, and be gentle!

 

 

 

 

CHAD

Link to comment
Share on other sites

Let me ask a stupid question. When I was doing my Army training in the TH-67 (bell 206) we pumped out a PPC (performance planning card) everyday where we figured out our max torque, cruise torque, etc for the day... We, based on that card would know if it were a engine or a transmission limit... Does the civilian world, either the r22 or 300 have anything like that? To tell you that you would hit an engine limit or transmission limit first for that day?? Thanks, and be gentle!

 

In the R22 you have a placard where you figure your 5 minute take off power and max continuous power based on outside air temp. The checklist has you figure those along with Vne for as part of the pre startup checks. It doesn't specify engine or transmission limit.

Link to comment
Share on other sites

I was just at the safety course last week. Both Frank and Tim Tucker spoke of the one and ONLY single reason the engine was de-rated for, and that SINGLE REASON, was for, as mentioned, power availability for higher altitude flying, period. Tim especially made a point of this.

 

He then went on to say that as a RESULT, but not even a concern to Frank when he decided to de-rate them, was that it does extend parts life etc etc.

 

He also made a point that nothing has actually been done to the engine, the card we all use to figure what MP we can use based on temp is what de-rates the engine.

If you look at the bottom corner of the chart it says full throttle, meaning that we always stop raising collective based on the temp chart at approximately 124 BHP, at the height of 8000 ft and OAT of 30c we will have the throttle all the way open to be able to fly and using all the HP that engine has to fly at that combo.

 

What I wish they would really make clear and specifically address in the POH is that using carb heat does not really cause you to have a loss in power you have available. IE, Tim stated that if you determine that your MP allowed is 20, and if you pull carb heat, and the MP goes up by one inch, you can then actually now use 21 as your new MP limit, while carb heat is being used, since the engine has the extra power available due to the "de-rating".

 

Yes the engine is working harder to keep it aloft, but you are still well below the 180 hp it can actually produce and so you are still with carb heat, only asking it for the 124 the chart figures are designed to keep you in. I made a point of asking him about it 2 more times after he explained it.

 

I told him every one of my instructors have said at one time or another, lets lower carb heat for this since we are not in the yellow so we don't lose any avail. power, and he said that that is not the case. I mentioned amending the POH or sending out some sort of bulletin and his answer was that we have been teaching this info for years at the safety course, so everyone should know it.

 

So I bet you can guess what I put in my critique. :D

Link to comment
Share on other sites

The 269B is "derated" in the same way the 300C is.... The B model is limited to 26.1 inches manifold at sea level and can maintain take-off 5 minute power up to 3900 feet (180 hp) and max continuous (160hp) up to 7200 feet.

 

The C model is 26 inches (standard atmosphere) up to 4200 feet (190 hp) and there is no 5 min. rating or take off rating... all power (up to 26 inches) can be used at all times.

 

The A models still have the 180 hp max power 5 minute rating but can use as much manifold as available (engine is 180 hp).. max continuous is 160 hp (26.2 inches)

 

I know we've been over the "derated" topic before but wanted to clarify the 300's

 

The B model is derated? I guess I just don't remember having to consult the MP chart when I flew the B, but I only have 7 hours in that model. As to the A model, some have the 5 minute 180 HP limit, others you can pull 180 all the time, just depends on the helicopter. I just didn't want to confuse things by adding that.

Link to comment
Share on other sites

There are no A models that you can pull full power anytime you want. All A models have a 5 minute takeoff rating (180) and a max continuous rating (160 hp)

Just like with the R22.... some pilots just choose to regard the 5 minute max power as a "anytime they want" type of placard since the dynamic components are essentially the same as the 300C that has a higher (190 hp) rating for all operations.

 

Consult the Type Certificate Data Sheet to compare the models.

Edited by apiaguy
Link to comment
Share on other sites

I told him every one of my instructors have said at one time or another, lets lower carb heat for this since we are not in the yellow so we don't lose any avail. power

 

captkirkyota,

I have had nearly ALL of my CFI's say to "Tell me (cfi) when to reduce carb heat, at approx 100 agl" so you don't have to take your hand off the collective, while flying dual. Esp on those hot humid days. They say solo, just leave the heat on and land, then turn off the heat.

Link to comment
Share on other sites

I think I only have a vague understanding of the R22 being de-rated. Can anyone explain this and WHY they would de-rate the engine?

 

 

Thanks.

 

 

OK, I didn't read everyone's answer but I think Franky de-rated it in order to get lycoming to put on a longer TBO from 1800hrs to 2200hrs. But lycoming told Franky that if they were to put a longer TBO then he (Franky) would have to de-rate the engine and not run it at full throttle like they do in fixed-wings. But I'm sure power and performance had something to do with it as well. Just my two cents.

Link to comment
Share on other sites

OK, I didn't read everyone's answer but I think Franky de-rated it in order to get lycoming to put on a longer TBO from 1800hrs to 2200hrs. But lycoming told Franky that if they were to put a longer TBO then he (Franky) would have to de-rate the engine and not run it at full throttle like they do in fixed-wings. But I'm sure power and performance had something to do with it as well. Just my two cents.

 

You are also correct. From 1800 to 2000, then he convinced them to go to 2200 based on the condition of engines that were coming in for rebuild. Then he got them to lighten up the cylinder walls for the 44 and still keep the 2200 TBO.

Link to comment
Share on other sites

Rocky- be careful here. The R22 is one very light weight ship because the components are built light weight and designed to take 131 HP not 180 HP. You can take out the main or T/R transmissions, bearings, mast stresses, etc, if you pull 180 HP when those components are designed for much less. Of course, you probably won't be flying it when it fails, because these stresses are cumulative in nature...so some poor skinny guy will be in the ship when it falls from the sky. However, I agree that if you need to pull the power to keep from bending metal then do so....just report the excessive MP so that your mechanic can can check the ship before the skinny guy gets in.

Fly Safe !

Goldy

 

As an A&P IA, if someone reported exceeding the MP and I didn't know better, the first place I would look is the MM for the inspection procedure. I wouldn't find one there, so I would call the factory and they would explain there is no inspection required.

 

There was one in flight failure before TBO that was thought to have been from pulling excessive MP. It was in South America as I recall and it was two robust fellas flying significantly over gross and they pulled well over the max limit MP in flight all the time.

 

So, even the dozen or so over MP limit pulls that occur during some typical training flights will not be enough to cause a premature failure. This is right from the experts at the factory.

Link to comment
Share on other sites

What do you mean by "lowering the RPM slightly reduces noise." ?... The derating isn't from the reduction in RPM, and Engine/Rotor RPM is almost entirely constant in powered flight. You completely lost me on that statement.

 

The 100% engine RPM was 2550 RPM and the 104% engine RPM is 2652 RPM, not the 2700 ROM that the engine is rated.

 

 

I was just at the safety course last week. Both Frank and Tim Tucker spoke of the one and ONLY single reason the engine was de-rated for, and that SINGLE REASON, was for, as mentioned, power availability for higher altitude flying, period. Tim especially made a point of this.

 

He then went on to say that as a RESULT, but not even a concern to Frank when he decided to de-rate them, was that it does extend parts life etc etc.

 

He also made a point that nothing has actually been done to the engine, the card we all use to figure what MP we can use based on temp is what de-rates the engine.

If you look at the bottom corner of the chart it says full throttle, meaning that we always stop raising collective based on the temp chart at approximately 124 BHP, at the height of 8000 ft and OAT of 30c we will have the throttle all the way open to be able to fly and using all the HP that engine has to fly at that combo.

 

What I wish they would really make clear and specifically address in the POH is that using carb heat does not really cause you to have a loss in power you have available. IE, Tim stated that if you determine that your MP allowed is 20, and if you pull carb heat, and the MP goes up by one inch, you can then actually now use 21 as your new MP limit, while carb heat is being used, since the engine has the extra power available due to the "de-rating".

 

Yes the engine is working harder to keep it aloft, but you are still well below the 180 hp it can actually produce and so you are still with carb heat, only asking it for the 124 the chart figures are designed to keep you in. I made a point of asking him about it 2 more times after he explained it.

 

I told him every one of my instructors have said at one time or another, lets lower carb heat for this since we are not in the yellow so we don't lose any avail. power, and he said that that is not the case. I mentioned amending the POH or sending out some sort of bulletin and his answer was that we have been teaching this info for years at the safety course, so everyone should know it.

 

So I bet you can guess what I put in my critique. :D

 

You must be a flat lander! LOL Applying carb heat certainly does reduce you max available power. You only have close to 180HP available at sea level on a standard day. But on a nice warm day here in Colorado, we might only start out with 130HP max and adding carb heat causes us to lose another 20 or so HP. Doesn't matter if you can pull an extra inch if that inch is not even available.

Link to comment
Share on other sites

The 100% engine RPM was 2550 RPM and the 104% engine RPM is 2652 RPM, not the 2700 ROM that the engine is rated.

 

 

 

 

You must be a flat lander! LOL Applying carb heat certainly does reduce you max available power. You only have close to 180HP available at sea level on a standard day. But on a nice warm day here in Colorado, we might only start out with 130HP max and adding carb heat causes us to lose another 20 or so HP. Doesn't matter if you can pull an extra inch if that inch is not even available.

 

I'm training where it is regularly 5k DA during the summer. :P

 

I'm just quoting what I was told 3 times from Tim Tucker last week at the safety course.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...