Advice on climbing to FL240

[aviatoreb]

There isn't any real advantage in this...if cylinders start getting hot, just lower the nose for faster airspeed in the climb. Leveling off to give the engine a "break" is just going to provide an extremely short fluctuation in CHT. Literally within a minute or so of starting your climb again, the cyl temps will be right back where they were.

I would just climb at whatever the max continuous power is and get to altitude as quick as you can.

I'm sure you can make quite a climb at 140 KIAS or so.

 

Seriously the rocket has superb cooling.  In the winter I climb with cowl flaps closed.  My worry in the winter is keeping the engine warm enough - not keeping it cool enough.

 

As for 02 - if you are flying at 02 levels, don't forget to put 02 continuity on your preflight checklist.  Make sure you get positive feedback that your O2 is working today, and that you have plenty of it, that your mask etc is ready to go and all plugged in before you start the engine, and that your emergency o2 is also ready to go.

[jlunseth]

I have been to FL240 and to FL230 several times in my 231, which has quite a lot less HP and not the robust cooling of your Rocket.  I am at FL200 or 210 virtually every long flight.  It is not a big deal.  Cooling is the only real issue and it should not be an issue at all in the Rocket.  Climb full rich, don't even think about leaning in the climb, and as was mentioned if the temps get up where you don't want them just reduce your climb rate and increase your airspeed. 

 

The only reason I don't go to 240 very often is that the time of useful consciousness falls fairly quickly above 220, so I go up there when I have a reason to but not as a matter of routine.  I have an oximeter, a mic'd mask, built in O2, and the best safety device in all of that is my old school Precise Flight flow meter.  It is the type with a little ball that goes up to show there is O2 flow, and it sits in my lap, so if I want to check I just look to see that the ball is up where I want it and if it is, I have all the O2 I need.

[Yooper Rocketman]

I have been to FL240 and to FL230 several times in my 231, which has quite a lot less HP and not the robust cooling of your Rocket.  I am at FL200 or 210 virtually every long flight.  It is not a big deal.  Cooling is the only real issue and it should not be an issue at all in the Rocket.  Climb full rich, don't even think about leaning in the climb, and as was mentioned if the temps get up where you don't want them just reduce your climb rate and increase your airspeed. 

 

The only reason I don't go to 240 very often is that the time of useful consciousness falls fairly quickly above 220, so I go up there when I have a reason to but not as a matter of routine.  I have an oximeter, a mic'd mask, built in O2, and the best safety device in all of that is my old school Precise Flight flow meter.  It is the type with a little ball that goes up to show there is O2 flow, and it sits in my lap, so if I want to check I just look to see that the ball is up where I want it and if it is, I have all the O2 I need.

Good points. I was coming out of Atlanta (actually Griffin) after delivering my F model to it's new owner in April and had reduced the RPM and manifold to cruise climb, 2500 and 35"s. It wasn't too long and the CHT's were hitting 400. I increased the RPM to max, 2650 and manifold to full, 38" and the temps came right back down. Also had a flight from Milan TN visiting my future painter to Geenville SC where I had filed FL230 for weather, in October 2013,and had to slow the climb to keep temps down under 400. I was alone on that flight too.

I rarely have an issue, but there can be times that you need to manage CHT's.

[Hondo]

Read Martha King’s  ‘When not to talk to ATC’ in the April issue of FLYING magazine.

[Houman]

Well my attempt to go to FL240 was stopped by a freaking CHT going very high. I have #6 going always a good number of degrees hotter, but this time, it got as hot as 425, even if we decided to climb at about 500 ft/min, all other temps on other cylinders were very normal, in ther 350 range.

I guess I got a problem with number 6....

[Yooper Rocketman]

Well my attempt to go to FL240 was stopped by a freaking CHT going very high. I have #6 going always a good number of degrees hotter, but this time, it got as hot as 425, even if we decided to climb at about 500 ft/min, all other temps on other cylinders were very normal, in ther 350 range.

I guess I got a problem with number 6....

Sorry to hear. You may want to check that injector, as that cylinder may be running a bit leaner than the rest.

[aviatoreb]

Sorry to hear. You may want to check that injector, as that cylinder may be running a bit leaner than the rest.

 

That is a good thing to check, but I am guessing it is not it since he shows a picture of the EDM700 and it says 1380 - 408.  1380 is not all that lean.

 

Houman, at what altitude did it start getting hot?  Was all normal until you reached a hot altitude?

 

The air is VERY thin up there - less for cooling - but I never had that problem before, although I RARELY go above FL21.  Other than increasing IAS a bit (lowering nose) above 17,000 or so, the rocket cooling is generally sufficient to keep the cylinders relatively cool.

[RocketAviator]

Well my attempt to go to FL240 was stopped by a freaking CHT going very high. I have #6 going always a good number of degrees hotter, but this time, it got as hot as 425, even if we decided to climb at about 500 ft/min, all other temps on other cylinders were very normal, in ther 350 range.

I guess I got a problem with number 6....

Not sure if the images your showing were during your climb but if so and your fuel flow was 22.5gph that would cause my Rocket CHT to be Hot! I climb out at close to 33gph on a hot day and less when cold I adjust mixture to keep CHT below 380 during take off. I typically climb out at 1200fpm @ 132kts. Home base high desert and hot often.

Also my engine anayliser first had the banjo under the spark plug temapture prob that consistently indicated 45 hotter, changed to new dual sensor which resolved the higher single CHT issue display.

Now you've got my interest up, I've climbed to and flown at FL 21 but never higher than that. No problem with climb but I was not in any hurry don't recall what my climb rate ended up as. I'll let you know when I fly next.

[jlunseth]

+1 on the fuel flow comment. Again, I own a 231 not a Rocket so don't know the engine intimately, but the max fuel flow range for my 231 is 22.5-24, so your Rocket is on the low side of that and producing 305HP rather than my engine's 210, It sounds low to me. My guess is that you are either leaning for the climb, which will indeed give you nice toasty CHT's, or the fuel flows are not properly set up for your engine.

[Parker_Woodruff]

What is your takeoff fuel flow?

[Houman]

My fuel flow was at around 29 I think at takeoff, I climbed full rich, never leaned it during climb, and all my cylenders were just fine beside #6. Wondering if it is going bad on me, since at last annual (when I bought the plane), it had the lowest compression, it was 68/80, but according to the mecanic still in good condition.

The engine has 200 hours on it, so a bit surprised that it would go bad this fast.

[M20F]

Couple things that I see. You fuel flow is low, Rocket lists 22 GPH at FL240 cruise (http://www.rocketengineering.com/content/rocket-conversion) so seeing 22.5 in the climb if you weren't leaning indicates the mixture needs adjustment. Second 200hrs is meaningless without a time reference on the rebuild. 200hrs on a six month since top/major engine is different than 200hrs since top/major in 20yrs. Lastly climb rate isn't relevant (500 FPM reference) it is about IAS/TAS so without knowing the speed hard to provide feedback there.

[Yooper Rocketman]

Not sure if the images your showing were during your climb but if so and your fuel flow was 22.5gph that would cause my Rocket CHT to be Hot! I climb out at close to 33gph on a hot day and less when cold I adjust mixture to keep CHT below 380 during take off. I typically climb out at 1200fpm @ 132kts. Home base high desert and hot often.

 

 

I have never seen under 30 GPH at full throttle, full RPM.  You are climbing at full throttle and 2650 RPM, right?  I usually see 33 GPH.  If you are under that, this is the first item you should be looking at.  If you get that figured out and it doesn't help. I would try swapping out the #4 and #6 CHT sensors.  That way you can verify it's not an indication problem.

 

Just to reinforce how important fuel flow is to cylinder cooling, when I picked up the Bonanza for our mercy flight organization at Tornado Alley after the new engine and turbo were installed (big bore continental), I was taught to turn the boost pump on low at 5,000' and high at 10,000', and not turn it off until in cruise and cylinder temps were stable below 400 degrees.  The fuel is used to "cool" the cylinders as much as it is used in combustion.

[Houman]

well I never fly at 2650 more than 30 seconds after takeoff, I was told not to hold the engine at the red line for too long, so I usually dial back to 32 or 33 MP and 2400 Prop RPM. My transition instructor had a lot of experience with the Rocket engine, but not in a Mooney ( he is an ATP ).

 

As for the low boost pump, I have never turned that one beside when having a bit of trouble starting the engine. I went trough the normal and Rocket POH when I got the plane and can't remember reading anything about that, I understand that the fuel would be used for cooling, but wouldn't that be too much fuel or cause other issues.

 

Unfortunately we didn't have the 3rd person on board that was suppose to film everything and now the whole interior of the plane (seats, carpets, sidewalls ) are all removed for our redo in a week. So I will try these once it is ready again.

 

I would be really interested in the boost pump thing, if it is not dangerous in flight, I would think it would have a great effect cooling the cylinder heads. I will also try to swipe the readers to see if it is a reader problem.

 

Thanks ! 

[Yooper Rocketman]

Houman,

 

Sorry, didn't intend to lead you to believe this was a technique used on the Rocket, thought about that post right after I sent it.  That was just to reinforce how important fuel flow is.  On the Rocket, the hi and low settings for electric fuel pump are just in case of mechanical fuel pump failure (from what I remember).  I have never used that pump in flight.  I do use the boost for priming before start, but that's another switch.

 

I was taught to use 25 x 35 for climb (2500 RPM and 35" of manifold) OR 2650 RPM and 38" for full power climb, OR to keep the CHT's down during the climb in warmer weather.  I am home, so don't have my Rocket manual with me, but I believe if you look in your manual, you will find that those are the two options listed for climb settings.  I have done the full throttle, 38" climb on my engine since OH, and am at 270 hours past TBO, so it appears the engine likes it.

 

This may have nothing to do with your problem, but it sure seems worth looking into.  As I noted in an earlier post, I had problems right after purchasing my Rocket, down in Atlanta in April after delivering my F to the new owner, with the temps going over 400 CHT on climb out at 25 x 35, and went to full throttle and prop and dropped the CHT's under 400 in minutes.

 

Good luck!

[Houman]

Thanks Tom, that is worth the try, I guess the extra fuel flow with the full throttle at 38 MP should help.

[Parker_Woodruff]

well I never fly at 2650 more than 30 seconds after takeoff, I was told not to hold the engine at the red line for too long, so I usually dial back to 32 or 33 MP and 2400 Prop RPM. My transition instructor had a lot of experience with the Rocket engine, but not in a Mooney ( he is an ATP ).

What does your POH say about the max continuous power for the engine in your Rocket? Don't go by what the fears are about "red line". If Rocket allows full rich and max power all the time in the climb, then do that, assuming your fuel flow is sufficient. Do climbs at the max continuous power specified by Rocket Engineering. This is not necessarily the suggested climb power. It may, in fact, be 100% power.

My Mooney flew the coolest with climbs at max power (39" MP, 2600 RPM). Only upon leveling off would I reduce power to a cruise setting.

[Parker_Woodruff]

Houman,

Sorry, didn't intend to lead you to believe this was a technique used on the Rocket, thought about that post right after I sent it. That was just to reinforce how important fuel flow is. On the Rocket, the hi and low settings for electric fuel pump are just in case of mechanical fuel pump failure (from what I remember). I have never used that pump in flight. I do use the boost for priming before start, but that's another switch.

I was taught to use 25 x 35 for climb (2500 RPM and 35" of manifold) OR 2650 RPM and 38" for full power climb, OR to keep the CHT's down during the climb in warmer weather. I am home, so don't have my Rocket manual with me, but I believe if you look in your manual, you will find that those are the two options listed for climb settings. I have done the full throttle, 38" climb on my engine since OH, and am at 270 hours past TBO, so it appears the engine likes it.

This may have nothing to do with your problem, but it sure seems worth looking into. As I noted in an earlier post, I had problems right after purchasing my Rocket, down in Atlanta in April after delivering my F to the new owner, with the temps going over 400 CHT on climb out at 25 x 35, and went to full throttle and prop and dropped the CHT's under 400 in minutes.

Good luck!

Thanks for posting what the POH says. Glad that full power climbs can be made with this engine.

[Houman]

Well here is what I have in the Rocket STC Manual... I guess I will try full power next time...

 

 

[Yooper Rocketman]

Must have been bugging you as much as me.  I went out to the airport and got my POH, Rocket Supplement, as well.   I bought my Rocket out of the Seattle area, and scheduled my PPI down in Cottage Grove, OR.  The seller flew me and my best friend (A&P and Mooney owner) down there in the Flight Levels, so during the flight he showed me the cruise climb, cruise, and descent power settings he was taught.  He sold me the Rocket with only 300 hours on the conversion.  He had been to Spokane, so don't know if his education came from Rocket or the owner that did the conversion. 

 

Nice to review the manual.  I learned to fly it that way when I bought it (and am sure we reviewed the manual as well), but haven't really looked at that part of it since 2001.

[kmyfm20s]

Normal climb in one place is 34" at 2300 rpm and 34" at 2500 rpm in your STC manual. I would think 2300 rpm is incorrect?

[Houman]

Well there was an AD if I remember well requiring the prop to be run at 2400 according to my transitional CFI, I did look it up a while back and it was there but for cruise I think, I will have to dig it up and see.

 

I guess RPM will have an impact on CHT temperatures, right ?

[kmyfm20s]

With fixed timing increased rpm will push peak pressure further away from TDC and reduce CHT according to the APS guys. Unless you have detonation which is controlled by mixture. So cooling the cylinders is done by cowl flaps, airspeed, fuel (very ROP) or sucking air (LOP). I don't fly a turbo but I have read about people climbing LOP since you have fixed MP, FF and RPM.

[Yooper Rocketman]

Well there was an AD if I remember well requiring the prop to be run at 2400 according to my transitional CFI, I did look it up a while back and it was there but for cruise I think, I will have to dig it up and see.

 

I guess RPM will have an impact on CHT temperatures, right ?

 

Never heard of that AD?  Been running mine in cruise at 2300 / 30" for 1870 hours?  Hard to believe three different shops and  three IA's missed that.  Do you have the AD number?

 

I just went on the FAA's website  with the AD listings and nothing for the TSIO520NB or for the M20K in regards to RPM limitations.

[RocketAviator]

well I never fly at 2650 more than 30 seconds after takeoff, I was told not to hold the engine at the red line for too long, so I usually dial back to 32 or 33 MP and 2400 Prop RPM. My transition instructor had a lot of experience with the Rocket engine, but not in a Mooney ( he is an ATP ).

 

As for the low boost pump, I have never turned that one beside when having a bit of trouble starting the engine. I went trough the normal and Rocket POH when I got the plane and can't remember reading anything about that, I understand that the fuel would be used for cooling, but wouldn't that be too much fuel or cause other issues.

 

Unfortunately we didn't have the 3rd person on board that was suppose to film everything and now the whole interior of the plane (seats, carpets, sidewalls ) are all removed for our redo in a week. So I will try these once it is ready again.

 

I would be really interested in the boost pump thing, if it is not dangerous in flight, I would think it would have a great effect cooling the cylinder heads. I will also try to swipe the readers to see if it is a reader problem.

 

Thanks !

Do NOT need to use boost fuel pump on Rocket unless mechanical pump failure according to my Rocket POH. I have never used either except to test at each preflight. Certainly not during take off or climbing as I did with my Saratoga.