LOP tries in the Rocket

[Houman]

Hi,

Just flow today from Montreal to New York and staying at KLDJ (Linden), during the flight I tried running LOP with my EDM 700 ( My Fuel Flow is beside on a Hoskins FT101 ).

The LOP went well on all cylenders and with the GAMI injector, my GAMI spread is about .7 GPH, so pretty good, all CHT's are well below 400 an EGT's are in the 1400 to 1500 and it's not long from 1st cylender to 6th cylender showing lean on the EDM 700, but not long after LOP is attained my TIT goes up fast and gets over the 1650 limit, when the overheat light went on, I went back to rich...

What am I doing wrong or is this normal, should I have leaned it more or what ???

Thanks !!!

[carusoam]

Welcome to NJ,

There is a really good recent thread on this topic for turbo Mooneys...

Apparently, peak for the cylinders comes before peak for the turbo.

JLunseth I believe is one of the authors....

Try this...

http://mooneyspace.com/topic/9165-m20k-leaning-and-engine-temp-practices/

Best regards,

-a-

[aviatoreb]

Welcome to NJ,

There is a really good recent thread on this topic for turbo Mooneys...

Apparently, peak for the cylinders comes before peak for the turbo.

JLunseth I believe is one of the authors....

Try this...

http://mooneyspace.com/topic/9165-m20k-leaning-and-engine-temp-practices/

Best regards,

-a-

 

Hi FormationHY - yeah - what he said.

 

To add - in my experience 0.7gph was not enough for my engine to run smoothly lean of peak.  To run smoothly I needed to swap injectors around (didn't need to get GAMIs) to achieve 0.4. Then I chased some pin hole sized holes in the baffling.  And a new Mags set.  Now it runs decent smooth LOP.  But just as you found, at higher power settings I hit TiT max anywhere near Peak.  So to avoid hot Tit I need to be either deep LOP at high settings - meaning lost power, or just lower MP settings, again not high power settings.  End of the day - I am only happy running LOP at 60% or less or so - at TiT <1600.  So at <13gph LOP I can make 170-180TAS from low Teens up (depending on how high) which is nice for long range, but I can't really go faster LOP since I am tit limited as I said.  Need to go ROP for more power.  And LOTS more fuel.  I usually run ROP since I like speed.

 

There was a guy on here a few years ago who was running his rocket at 75% and up LOP successfully at the same kind of rocket speeds we get ROP a 75%.  (Remember percent power LOP is measured by multiplying your gph by 13.7 hp/gph).

 

The IO550TN is a higher compression engine from tornado alley (featured on the Bonanza) and they report LOP with low TiT and they run 85% LOP routinely.  If only I could run 85% LOP on my rocket wow that would be fast.  Faster obviously than I can run on my 75% ROP and on less fuel.

 

Tornado Alley should really make a TN conversion for the Mooney Ovation - that would turn the Ovation into the speed king of Mooney's and a great LOP machine.

[Houman]

Hi Erik,

I love the speed as well, my wallet loves it a bit less, but made KBTV to KLDJ in 1h19 minutes of air time, with an average GS of near 200 Kts runing ROP and wanted to get there before sunset.

When you say deep LOP, do you mean you continue to leaning after all 6 cylenders are indicated as lean on the EDM ?

Not sure I understand exactly what you mean...

[aviatoreb]

Hi Eric,

I love the speed as well, my wallet loves it a bit less, but made KBTV to KLDJ in 1h19 minutes of air time, with an average GS of near 200 Kts runing ROP and wanted to get there before sunset.

When you say deep LOP, do you mean you continue to leaning after all 6 cylenders are indicated as lean on the EDM ?

Not sure I understand exactly what you mean...

 

Hi Houman, Don't forget the k in Erik.

 

Yes, I mean to keep the Tit cool, you can lean and lean further well past peak (on the lean side) which cools everything off , but also results in less power, less fuel flow, and possibly rough engine if you are not extremely well balanced to run >50 or 75 LOP.

 

Even ROP, you can slow a rocket down to 170s and use maybe 13 or 14gal.  They say you can do 231 speeds on almost 231 fuel flow....No one says you have to run 18 or 20 gallons ROP, but its so much fun to go >200kts.

[Houman]

Sorry for the miss-spell, in french your name is written with a C at the end...

and yes it is fun to go that fast, I got hooked on the performance of the Rocket since the 1st time I tried it... It is a hell of a machine...

[aviatoreb]

Sorry for the miss-spell, in french your name is written with a C at the end...

 

 

Oui, je sais. Eric en français.

 

and yes it is fun to go that fast, I got hooked on the performance of the Rocket since the 1st time I tried it... It is a hell of a machine...

 

 

Oui!  Exactement!  Supere genial!

[RocketAviator]

I run my Rocket LOP at 80% plus all the time. Lean until Turbo is below 1625!

35MP smooth at 16.3 GPH 185-190 TAS @ 12000

FormationHY did you get the images I sent you with the settings you and I discussed.

About 13.9 or 14 GPH ay 30MP as I recall.

Lower MP allows for less of a LOP and lower TIT.

[Houman]

Hi, I got your images, thanks very much, I will try to the LOP more on my flight back from KLDJ to CYMX that should take me almost 2h, so plenty of time to try it... I was doing my 1st try @ 7500, since I don't like to use O2 when I fly with my 8 year old son alone,

So, I know now how to do LOP on my EDM 700, and I guess I shoud'nt worry when my TIT goes up, I should continue to lean it more till TIT drops below 1625... I usually try to not run my TIT over 1600, even less than 1550, I had read somewhere that running it hot too long will drastically shorten the Turbo TBO time and that running it under 1550 was well advisable...

Thanks for any input...

[aviatoreb]

I run my Rocket LOP at 80% plus all the time. Lean until Turbo is below 1625!

35MP smooth at 16.3 GPH 185-190 TAS @ 12000

FormationHY did you get the images I sent you with the settings you and I discussed.

About 13.9 or 14 GPH ay 30MP as I recall.

Lower MP allows for less of a LOP and lower TIT.

 

Where did you get 80% measurement?

 

I am interested what is the rest of the settings - rpm, MP, and how far leaned of peak is that setting.  How many gph are you leaned from peak and how many degrees lean of peak?

 

As I understand it, lean of peak, power is proportional to fuel flow.  The multiplying factor is 13.7 hp/gph.  So 16.3 gph*13.7 hp/gph=223hp.

 

223hp/305hp=73%   - also I think the speed you are reporting is more like what you might see at 73% power than at 80% power (244hp).  Still good fuel economy.

 

Still that is pretty good.  How many degrees are you leaned from peak when at 1625?  Have you done the peak test to confirm that your TiT peaks at 1700 - to ensure that you are no inadvertently running closer to max than you think? (or past) keeping in mind that 1625 is very close to the max 1650 allowed.  For example about a month ago I did my peak test as called for in the POH - and I found on that day that I peaked at 1680 (at 34'' and 2400 I think was the POH called for setting of the test).  That means that it is supposed to be 1700 so I would read max as shifted by 20 on that day, so max becomes 1630.  So if you are going to be running close to peak Tit be sure you are using an accurate number.

 

Mostly I strive to keep temps below 1600Tit when LOP.  Which is why its lower rpms and lower power settings for me if I LOP.

 

Some people would say that my "babying" is misdirected since they would argue that the peak pressures are lower LOP even if at 80% vs 75% ROP  - and so since I run my engine 75% ROP, I would be better off running it 75 or 80% lean of peak, even despite the high TIT.

[RocketAviator]

Erik

I have dual TIT and one is calibrated. The Engine Monitor I have installed is Insight G4, it calculates the HP. Just last week I updated the firmware so now it calculates HP in both LOP & ROP. The formula as I understand it is different, but I won't even try to debate that with a mathematical guru l I keep you lol.

I'll post images of older and recent shots of the G4 screen.

[aviatoreb]

Erik

I have dual TIT and one is calibrated. The Engine Monitor I have installed is Insight G4, it calculates the HP. Just last week I updated the firmware so now it calculates HP in both LOP & ROP. The formula as I understand it is different, but I won't even try to debate that with a mathematical guru l I keep you lol.

I'll post images of older and recent shots of the G4 screen.

 

Its not really the kind of math that I specialize in - its more engineering and just stuff I learned here and there as a hobby flier - so feel free to debate me.  I hold very little special credential in this arena.

 

But...  the idea of power being proportional to fuel flow when lean of peak means the more fuel you can push throw the engine the more power you can make - but keeping proper settings (red box limited and also tit limited).  As far as I understand it - 80% of 305hp is 244hp and 244hp/(13.7hp/gph)=17.8 gph. SO unless you can push 17.8 gph through the engine while lean of peak and within acceptable temp limits the you aren't running 80%.  So I think your instrument's software is in error. Obviously the alternative is that I am in error.  :-O   Still,l what you are running sounds like some impressive LOP setting in any case.