550 ops- running wide open

[Cardiff Kook]

I read this long tutorial on 550 ops by john deakin. Its many pages.

That author recommends running big bore continentals at full throttle for the entire flight regardless of altitude. Only adjust mixture and rpm based on fuel burn requirements (edit: only applies to LOP operations.)

“In fact, on a properly conducted flight, the throttle will go fully open on takeoff, and remain there for the entire flight regardless of the cruise altitude, until somewhere in the descent when the airplane picks up too much speed. There is no functional difference between a partially closed throttle and a dirty air filter, and few would willingly fly with a dirty air filter.”

Hes obviously talking about unless there is some need to reduce airspeed (turbulence.)

Never heard of that. I generally run mine at 21/23 but I do wonder if I baby it too much which I know isnt great.

Is this “throttle wide open” a thing? Considerations?

 

[BC12D-4-85]

+

Gary

 

[Cardiff Kook]

+

Gary

Ha. Can of worms?

After watching a a two hour seminar by mike busch after i posted this I buy it for LOP operations. Air is in excess already in LOP operations so adding more doesnt add more power/stress. Power is controlled w mixture in LOP, and throttle in ROP ops.

 

[BC12D-4-85]

When the manufacturer recommends the procedure then proceed. They fulfill the warranty.

Gary

 

[BC12D-4-85]

Cardiff, so we have a common ground for discussion, how about linking the article you're referring to for all to evaluate? I can see full throttle ops above a pressure altitude, and am willing to learn more.

Gary

 

[RedOwlAirfield]

I can tell you that - at the altitudes I commonly fly - This winds up being pretty much the way things work. I fly a Cessna 180 with an O470U. Since my home field is at about 5000 FT and there's mountains all around, Pretty much every time I go anywhere its above 10,000. The manifold pressure is never enough to square up the settings so I tend to just leave the throttle full and use the prop if I want to change anything - which I rarely do until descent. Feels good and seems to work well and I haven't blown up the engine yet.

I do know the 180 POH has a bunch of charts for different altitudes showing what settings they recommend for what per cent of power. All of them do top out at some point - meaning that full throttle is expected above a certain point even for lower power settings.

 

[Cardiff Kook]

See attached.

Its 50 pages. Lots of supporting data from testsI believe were completed at GAMI test centers in Oklahoma.

Mike Busch of Savvy Aviation has lots of youtube videos where he preaches a similar practice. Mike runs his turbo 310 wide open, LOP throughout his flights as well.

 

[Cardiff Kook]

This method I believe is what is taught in the Advanced Pilot Seminars. Mike Bush and Deakin claim their enigines go 200%+ TBO

 

[sj]

This method I believe is what is taught in the Advanced Pilot Seminars. Mike Bush and Deakin claim their enigines go 200%+ TBO

3000hrs on continental cylinders? Not with a carb for sure.

sj

 

[BC12D-4-85]

I ran three IO-520's to TBO+ w/o cylinder work. At +100-125 ROP. It can be done providing CHT is monitored and maintained, and EGT controlled (it was done with a single cylinder Cessna probe). Now we have advanced electronics and better motors, so I'd hope for similar if not better results.

The author of the OP's articles writes well while carrying across his beliefs supported by some data. As far as the full open throttle while power and temps are adjusted elsewhere, I agree providing the pressure altitudes operated at are high enough, and the detonation margin sufficient.

If flying point to point "up there" or at low level but high elevations, ok. That's different than typical stop and go Bush flying Alaska or elsewhere, which often involves frequent excursions near Earth, or to numerous low elevation strips or water bodies.

Good points from the articles and worth a read.

Gary

 

[cthartman]

TCM 520's and 550's with tuned injectors can be flown WOT LOP without issue regardless of altitude provided the operator avoids the "red box." Does this require an increased level of engine monitoring? Yes. In addition to APS/Deakin guidance, TCM's Tips on Engine Care, published in 2011, states that LOP is an acceptable practice on numerous engine models (including 520/550's). Page 27 (attached herein), and elsewhere, provide guidance. Regardless of one's opinion on ROP/LOP debate, either methodology can result in long engine life with good practice. Personally, I would strongly encourage anyone considering operating WOT LOP to educate themselves beforehand. Deakin's Pelican Perch articles linked above is a good starting point. Cheers.

 

[mvivion]

First, read the specifications for YOUR engine. At least some IO-550 engines have a prohibition on leaning when operated at greater than a specified brake horsepower power setting. If I recall, that was 70 % on the ones I operated. So, Deaken/Bushe, etc offer suggestions.....the engine manufacturer MAY offer "requirements"......I'd definitely honor those first.

MTV

 

[cthartman]

First, read the specifications for YOUR engine. At least some IO-550 engines have a prohibition on leaning when operated at greater than a specified brake horsepower power setting. If I recall, that was 70 % on the ones I operated. So, Deaken/Bushe, etc offer suggestions.....the engine manufacturer MAY offer "requirements"......I'd definitely honor those first.

MTV

Your inference that I failed to read my engine specs is incorrect. I just didn’t stop there, I kept on reading. As a part of that knowledge gained, I posted to this thread an informative document published by TCM concerning engine care and operation whether it be ROP and LOP. Feel free to read it for yourself. I haven’t met anyone that didn’t take something from it. Nor have met someone that didn’t take something away from the other authorities referenced. Anyway, for clarification, WOT means the “throttle” position full only, not max power as you imply I suggested. The school of thought to operate LOP means adjusting the mixture control sufficiently to stay outside the “red box” at a permissible RPM setting. Leaner is cooler. If one reads the TCM document I referenced, Deakins articles, or takes the APS course, it becomes readily apparent that is the methodology to operate WOT LOP. Does the throttle have to wide open to run LOP? No, but it is preferable to do so as to avoid the temptation to increase throttle to “regain” lost power and end up inside the red box after be sufficiently LOP. Importantly, I cautioned anyone inclined to dip their toes in the LOP pool to educate themselves. It’s worth noting that at one point in time, TCM did not endorse LOP operations. But that is no longer the case. If you have a question about your specific model, call them at 1-888-826-5465 (this number is listed in the guide I referenced), or submit an email. You may find that despite what your original OM states, LOP operations are likely not prohibited now.

Moving along, the max recommended cruise power setting on every 550 I’m aware of (including mine own, and the IO550F model for that matter) is 78%, which is about 70-90 degrees WOT LOP. You can’t lean too much further than that without the engine starting to stumble. Not sure what the equivalent ROP setting would be, but the 550 is certified to operate max power 300 HP all day with the mixture full rich. 5 minute limitation on a 300 hp rated 520 at that setting. Limitation or recommendation, none of the referenced authorities would suggest operating high power LOP with a stumbling engine. It’s just common sense. But the problem with common sense is that it isn’t all that common. Back to the IO550 70% power setting you recall, you’ll find most authorities, including TCM, suggest operating 25-40 degrees LOP there, which results in a fuel burn around 14.3-14.5 GPH off the top of my head. That’s a nice “comfortable” LOP setting, WOT of course. LOP or ROP, just stay out of the red box. Cheers.

 

[mvivion]

You might try in bunching your panties. I was simply suggested that anyone operating these engines should first abide by the manufacturer’s requirements, THEN apply operating methods within those parameters. If nothing else, that doesn’t void whatever warranty that very expensive engine came with.

i did NOT suggest that any procedure you proposed would necessarily violate manufacturers requirement. As a long time CFI, I have many times observed pilots operating engines out of ignorance and the internet.

Example: I put 1300 hours on a 550 in a 206. Another pilot borrowed that plane, put 20 hours on it, it went right into 100 hour, and four cylinders were shot. How’d he run it? High power settings at low altitude, on floats.

Your recommended procedures are fine, as long as one minds the manufacturer’s rules.

 

[cthartman]

You might try in bunching your panties. I was simply suggested that anyone operating these engines should first abide by the manufacturer’s requirements, THEN apply operating methods within those parameters. If nothing else, that doesn’t void whatever warranty that very expensive engine came with.

i did NOT suggest that any procedure you proposed would necessarily violate manufacturers requirement. As a long time CFI, I have many times observed pilots operating engines out of ignorance and the internet.

Example: I put 1300 hours on a 550 in a 206. Another pilot borrowed that plane, put 20 hours on it, it went right into 100 hour, and four cylinders were shot. How’d he run it? High power settings at low altitude, on floats.

Your recommended procedures are fine, as long as one minds the manufacturer’s rules.

up one snarky comment with another all the while being pre

And yet you follow up one snarky comment with another. I remember attending a couple of seminars you spoke at in the late 80's, maybe early 90's. You were a bit aloof and preachy then too. In regards to that 1300 hours you put on the 550 equipped 206, did you strictly adhere to the TCM guidance running 75 degrees ROP at say about 24ish squared? If so, it turns that setting produces the highest internal cylinder head pressures and just as likely contributed to those cylinders premature demise. TCM quietly redesigned the 550D/F cylinders head fins after cylinders were prematurely failing on early models. It was largely attributed to long takeoff runs due to heavy weight with insufficient cooling. I too have a couple thousand hours running 520/550's. I've cruised exclusively LOP at high power, low altitude, and on floats with nary an issue. It can be done all day long operating outside of the red box. It's possible your cohort simply was the guy holding the keys when the cylinders failed. Finally, I'd also recommend that any big bore operator should borescope their cylinders annually regardless of their preferred method of operation.

 

[Cardiff Kook]

Whoa, Nelly!!

Lets all take a breath. (Thats a collective all. I will take one too.)

I appreciate everyones input in helping me answer the question. Lots of good info for me to chew on. Thanks for taking the time to share what you know.

 

[BC12D-4-85]

If I were fortunate to own the engine being discussed, I'd analyze the benefit and learn to manage the risks associated with either WOT or LOP ops at lower altitudes. Being ignorant beyond what I've read here, I'd probably weigh the savings in fuel against longevity others have experienced for similar missions. Not making TBO gets expensive.

Gary

 

[mvivion]

And yet you follow up one snarky comment with another. I remember attending a couple of seminars you spoke at in the late 80's, maybe early 90's. You were a bit aloof and preachy then too. In regards to that 1300 hours you put on the 550 equipped 206, did you strictly adhere to the TCM guidance running 75 degrees ROP at say about 24ish squared? If so, it turns that setting produces the highest internal cylinder head pressures and just as likely contributed to those cylinders premature demise. TCM quietly redesigned the 550D/F cylinders head fins after cylinders were prematurely failing on early models. It was largely attributed to long takeoff runs due to heavy weight with insufficient cooling. I too have a couple thousand hours running 520/550's. I've cruised exclusively LOP at high power, low altitude, and on floats with nary an issue. It can be done all day long operating outside of the red box. It's possible your cohort simply was the guy holding the keys when the cylinders failed. Finally, I'd also recommend that any big bore operator should borescope their cylinders annually regardless of their preferred method of operation.

No, I never operated that 550 at 24 square, because at the altitudes I operated, that setting would have exceeded the max rated hp specified by TCM. But, that’s pretty much what the other guy did: 25 squared. And I always ran that engine LOP.

 

[cthartman]

Whoa, Nelly!!

Lets all take a breath. (Thats a collective all. I will take one too.)

I appreciate everyones input in helping me answer the question. Lots of good info for me to chew on. Thanks for taking the time to share what you know.

You are on the right path. It's not easy to glean substantive information on this subject in any particular aviation forum when everyone has an opinion. However, beechtalk.com has numerous threads on this matter, and sometimes a no kidding real industry authority will chime in. You mentioned APS. Not sure if they still offer their online course, but it is worth the fee no matter how one chooses to operate these engines.

 

[skywagon8a]

Cardiff, Here is a link for the Maintenance and operator's manuals for the IO-550D: https://www.manualslib.com/products/Teledyne-Continental-Motors-Io-550-D-10455528.html After spending $50k (more now?) on a new engine, this is where I'd go for the answers.

 

[RaisedByWolves]

Cardiff, Here is a link for the Maintenance and operator's manuals for the IO-550D: https://www.manualslib.com/products/Teledyne-Continental-Motors-Io-550-D-10455528.html After spending $50k (more now?) on a new engine, this is where I'd go for the answers.

They are only 76k for a 550 now.

 

[dgapilot]

That’s the way we used to run the A36 I flew for many years, throttle wide open except for slowing down for landing.