R22 de-rated?

[RockyMountainPilot]

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

 

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

 

We are seeing DA's in the 5K range right now in the Denver area. In the summer we see 9K+. Anything below 5K is not considered high altitude operations in helicopters by most people. Here, we don't consider anything below 10K to be high altitude.

 

I think you either misunderstood Tim, or you took it out of context. When you apply carb heat, you reduce the max available horsepower of the engine. This you can find in almost any book relating to aircraft engines.

[captkirkyota]

We are seeing DA's in the 5K range right now in the Denver area. In the summer we see 9K+. Anything below 5K is not considered high altitude operations in helicopters by most people. Here, we don't consider anything below 10K to be high altitude.

 

I think you either misunderstood Tim, or you took it out of context. When you apply carb heat, you reduce the max available horsepower of the engine. This you can find in almost any book relating to aircraft engines.

 

Nope, did not misunderstand him, as I stated in my original post, yes the engine does work harder, but since it is only using 124 hp of the avail 180, you are not losing power in the sense that now you don't have that 1 inch that it went up when you added carb heat, you just get to up your limit by 1 inch too. IE before carb heat and flight you figure MP max continuos at 20, then at your hover you add heat and the MP, ( say at the hover is 16 ) increased by an inch. ( so now at 17 ) As long as you leave the heat on, your NEW max continuous can be 21, according to what they say at the factory course.

Does that make what I'm telling you they told me 3 times more clear? Text does not always convey that well.

[RockyMountainPilot]

Nope, did not misunderstand him, as I stated in my original post, yes the engine does work harder, but since it is only using 124 hp of the avail 180, you are not losing power in the sense that now you don't have that 1 inch that it went up when you added carb heat, you just get to up your limit by 1 inch too. IE before carb heat and flight you figure MP max continuos at 20, then at your hover you add heat and the MP, ( say at the hover is 16 ) increased by an inch. ( so now at 17 ) As long as you leave the heat on, your NEW max continuous can be 21, according to what they say at the factory course.

Does that make what I'm telling you they told me 3 times more clear? Text does not always convey that well.

 

 

You understand that you don't have 180HP available at 5,000 feet, correct? How many times have you had to pull more than your limit MP? Do you know how much power you can lose when you apply carb heat? Do you know that applying carb heat in summer will cause more power to be lost than in winter?

[captkirkyota]

You understand that you don't have 180HP available at 5,000 feet, correct? How many times have you had to pull more than your limit MP? Do you know how much power you can lose when you apply carb heat? Do you know that applying carb heat in summer will cause more power to be lost than in winter?

 

1.Yes I do.

2.Not that much, if any that I recall anyway.

3.I could figure it out with the chart prolly.

4.yes of course.

 

Ok, since text is not getting it across in brevity, here is a longer explanation. ( BTW I just called and talked to Tim right now and had him explain it again to me, this time he went into more detail than in class and instead of using 1 inch example numbers just made up for ease sake, he explained in better detail, which is exactly what I've been trying to say all along )

 

The engine does not know what DA or temp I'm at, all it knows is the temp of the air going in based on the CAT gauge.

 

Pulling carb heat to warm the cool morning air is just like what the sun does, so for this discussion, pulling heat at 7 am makes the air going into the engine the same temp as 3 pm in the afternoon. ( in effect raising the DA )

 

Since we are only using 131 hp of the 180 avail, in that sense, we do not lose performance power avail. ( assuming that you are still at an actual DA and temp combo that pulling carb heat does not put you at what would in effect be a DA that the engine could not produce the full 180 )

 

So, in the example he just gave me on the phone, he says, if you are in temps condusive to carb ice, while on the ground, appy carb heat and look at the temps on the CAT gauge. Use that temp to figure out your MP limit. So, 7 am, temp is 5c, pull heat, now it reads, 25c, use 25c to figure your MP limits on the chart. At 3pm, your temp is not condusive to ice, OAT is 25c, use 25c to figure your MP on the chart.

In that scenario, sense, whatever, you are not losing power, yes the engine is working harder and such, but pulling carb heat is just making the engine work like it does on a warmer afternoon, if you can fly and perform with no problem a maneuver at 3 pm in May, you can do it just as well in Jan with heat on.

 

Here let me explain, multiple times we have been flying and figured the MP before flight. Then later on doing some such maneuver that requires quite a bit of power, my instructors have said to me, hey lets reduce carb heat right now so we don't hit our MP limit and lose/limit our power.

 

My desire was that the POH would explain better that one should figure out the MP limits based on the CAT temps on the ground with heat applied so that scenario I just gave would not take place.

 

Then we could/would do like Tim said we should be doing, pull heat to get you out of the yellow and then fly the entire flight allowing the carb heat assist to do its jobs and adjust the heat up and down with the collective, and the only time we should need to touch the carb heat knob again would be full application of heat for an auto, then set it back to where it was before. In theory the assist feature should keep you from ever having to adjust the heat during the whole flight sans auto. ( right now we adjust the carb heat several times during flight and it seems ridiculous )

 

If this does not clear up what I'm trying to say, then I'm sorry, I KNOW what I mean, and what I was told, but typing that with my hunt and peck method and making it as understandable as having an actual conversation are not always possible. <_ src="%7B___base_url___%7D/uploads/emoticons/default_wink.png" alt=";)">

[RockyMountainPilot]

1.Yes I do.

2.Not that much, if any that I recall anyway.

3.I could figure it out with the chart prolly.

4.yes of course.

 

Ok, since text is not getting it across in brevity, here is a longer explanation. ( BTW I just called and talked to Tim right now and had him explain it again to me, this time he went into more detail than in class and instead of using 1 inch example numbers just made up for ease sake, he explained in better detail, which is exactly what I've been trying to say all along )

 

The engine does not know what DA or temp I'm at, all it knows is the temp of the air going in based on the CAT gauge.

 

Pulling carb heat to warm the cool morning air is just like what the sun does, so for this discussion, pulling heat at 7 am makes the air going into the engine the same temp as 3 pm in the afternoon. ( in effect raising the DA )

 

Since we are only using 131 hp of the 180 avail, in that sense, we do not lose performance power avail. ( assuming that you are still at an actual DA and temp combo that pulling carb heat does not put you at what would in effect be a DA that the engine could not produce the full 180 )

 

So, in the example he just gave me on the phone, he says, if you are in temps condusive to carb ice, while on the ground, appy carb heat and look at the temps on the CAT gauge. Use that temp to figure out your MP limit. So, 7 am, temp is 5c, pull heat, now it reads, 25c, use 25c to figure your MP limits on the chart. At 3pm, your temp is not condusive to ice, OAT is 25c, use 25c to figure your MP on the chart.

In that scenario, sense, whatever, you are not losing power, yes the engine is working harder and such, but pulling carb heat is just making the engine work like it does on a warmer afternoon, if you can fly and perform with no problem a maneuver at 3 pm in May, you can do it just as well in Jan with heat on.

 

Here let me explain, multiple times we have been flying and figured the MP before flight. Then later on doing some such maneuver that requires quite a bit of power, my instructors have said to me, hey lets reduce carb heat right now so we don't hit our MP limit and lose/limit our power.

 

My desire was that the POH would explain better that one should figure out the MP limits based on the CAT temps on the ground with heat applied so that scenario I just gave would not take place.

 

Then we could/would do like Tim said we should be doing, pull heat to get you out of the yellow and then fly the entire flight allowing the carb heat assist to do its jobs and adjust the heat up and down with the collective, and the only time we should need to touch the carb heat knob again would be full application of heat for an auto, then set it back to where it was before. In theory the assist feature should keep you from ever having to adjust the heat during the whole flight sans auto. ( right now we adjust the carb heat several times during flight and it seems ridiculous )

 

If this does not clear up what I'm trying to say, then I'm sorry, I KNOW what I mean, and what I was told, but typing that with my hunt and peck method and making it as understandable as having an actual conversation are not always possible.

 

 

You are missing my point. When you are at altitude, you might only have 140 HP available. If you apply carb heat, you can lose as much as 20% or 28HP. This leaves you with 112HP. Now, you can't even pull max continues much less max power. This is why your instructor tells you to turn it off. Also, any experience instructor will tell you that there are times they pull a lot of pitch when a students does properly perform certain maneuvers. They would rather have more then less power available to them when they pull beyond the max takeoff power. Even if they have the full 180HP available on a standard day at sea level, better that then the 145 to 155 or so HP they get with the carb heat applied.

 

If you were approaching a field for landing and at 10 feet you notice a thin wire in front of you, do you want that extra horsepower, or will you be happy with what you have with the carb heat on?

[captkirkyota]

You are missing my point. When you are at altitude, you might only have 140 HP available. If you apply carb heat, you can lose as much as 20% or 28HP. This leaves you with 112HP. Now, you can't even pull max continues much less max power. This is why your instructor tells you to turn it off. Also, any experience instructor will tell you that there are times they pull a lot of pitch when a students does properly perform certain maneuvers. They would rather have more then less power available to them when they pull beyond the max takeoff power. Even if they have the full 180HP available on a standard day at sea level, better that then the 145 to 155 or so HP they get with the carb heat applied.

 

If you were approaching a field for landing and at 10 feet you notice a thin wire in front of you, do you want that extra horsepower, or will you be happy with what you have with the carb heat on?

 

No I have not missed your point, you however have demonstrated that you only seek to argue, at least that is the way it seems, and have chosen to insert situations that have nothing to do with what I said I'd like for Robinson to do and that is to add more info to the POH about carb heat since it is such a confusing thing to so many people and was a big uproar in the class when I was there.

All your points are valid but are not what I was talking about, but what you decided to turn the subject into.

So you win, I'm done, you don't seem to want to see that I agree and do understand, and it seems that you do not want to understand what I was saying, so I'll just stop and you can be the winner.

Stay safe and keep on giving good instruction, but remember good teachers are also good listeners.

[apiaguy]

he he he.... schweizer's don't have carb heat.

 

No seriously... I think everyone was understanding what the other was trying to say... just not communicating it effectively.

[Goldy]

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

 

Ahhh, what does Tim know anyway !!

 

(Glad I can hide behind an avitar, he's doing a checkride of mine SOON !)

[RockyMountainPilot]

No I have not missed your point, you however have demonstrated that you only seek to argue, at least that is the way it seems, and have chosen to insert situations that have nothing to do with what I said I'd like for Robinson to do and that is to add more info to the POH about carb heat since it is such a confusing thing to so many people and was a big uproar in the class when I was there.

All your points are valid but are not what I was talking about, but what you decided to turn the subject into.

So you win, I'm done, you don't seem to want to see that I agree and do understand, and it seems that you do not want to understand what I was saying, so I'll just stop and you can be the winner.

Stay safe and keep on giving good instruction, but remember good teachers are also good listeners.

 

I read your posts and I was trying to understand what you were saying, but I am sorry if I did not. You stated "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." This is not correct. Carb heat does certainly effect your max power available. It may or may not effect your limit HP. You may still have 131HP available, or you may not depending on the altitude and temp. I was taught to use the carb air temp for calculating the MP back in 1994 when I first started flying helicopters. Most everyone I have flown with understands this, so I don't think this is a problem. I think the problem is that you do not understand why your instructor, who has probably pulled all 100% max available power in the past, would want as much power available before getting close to the ground.

 

In any case, there is no reason to get upset.

 

he he he.... schweizer's don't have carb heat.

 

No seriously... I think everyone was understanding what the other was trying to say... just not communicating it effectively.

 

Some 269A's and 269C-1 (300CB) models have carb heat.

 

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

 

 

Ahhh, what does Tim know anyway !!

 

(Glad I can hide behind an avitar, he's doing a checkride of mine SOON !)

 

Pat Cox is my goto man for anything mechanical.

 

Ask Tim about one of the checkrides he had in Colorado. But be sure to do this AFTER your ride.

[captkirkyota]

I was taught to use the carb air temp for calculating the MP back in 1994 when I first started flying helicopters. Most everyone I have flown with understands this, so I don't think this is a problem.

 

No one has ever told me before, they may know it and have just overlooked telling me, my first instructor was a brand new one and may have overlooked that, since it was summertime when I started, then when I switched to a more experienced one he may have thought it was already told to me. Either way, I was not the only one at the course that this was news to. It was an interesting break time conversation for many.

 

 

 

In any case, there is no reason to get upset.

 

Wasn't really, just seemed like you were trying to be antagonistic, so I apologize.

[captkirkyota]

I was taught to use the carb air temp for calculating the MP back in 1994 when I first started flying helicopters. Most everyone I have flown with understands this, so I don't think this is a problem.

 

No one has ever told me before, they may know it and have just overlooked telling me, my first instructor was a brand new one and may have overlooked that, since it was summertime when I started, then when I switched to a more experienced one he may have thought it was already told to me. Either way, I was not the only one at the course that this was news to. It was an interesting break time conversation for many.

 

 

In any case, there is no reason to get upset.

 

Wasn't really, just seemed like you were trying to be antagonistic, so I apologize.