Will a Gallon make a Big Difference?

[Missile=Awesome]

Our IO-550 in our Missile is flowing 26 Gallons at Full Power on Take Off.  Photos don’t show climb Cylinder Temps or EGT’s (These are cruise) and there is NOT a problem with the volts, well there is, but it is in the pin for the 830...Not an actual voltage problem...Here is question:

Will One Gallon (Getting Max Fuel Flow at full take-off/climb power make a significant difference on cylinder temps.  The missile is tightly cowled and has no cowl flaps so doing a cruise climb is preferred (still see 700-1000fpm), but we are seeing some temps in climb approaching and ticking above 400.  EGT’s are also significantly higher than I would expect.  (This is at 8500’).  Sea level is 27.4gph on IO-550.  We are going out of <1,000’ and seeing 26 to 26.5 max on full power fuel flow.  We are running boost pump in climb and still seeing elevated cylinder temps...

Appreciate input.

[jetdriven]

Consensus over on beechtalk is these big continentals like fuel flow on takeoff. Adding an extra gallon per hour on takeoff makes a huge difference in cooling And cylinder life. So get your mechanic guy to turn it up a little bit. 

[Missile=Awesome]

Just now, jetdriven said:

Consensus over on beechtalk is these big continentals like fuel flow on takeoff. Adding an extra gallon per hour on takeoff makes a huge difference in cooling And cylinder life. So get your mechanic guy to turn it up a little bit. 

Any thoughts on EGT’s in cruise?  I know they are just numbers, but I would think 1400 vs. what I am seeing...

[1980Mooney]

You appear to be flowing way too much fuel.  The Missile STC has an IO-550A.  There are currently 11 versions of IO-550 most with different fuel flow profiles and the profile above doesn't designate or match anything.

You need to be looking at TCM service bulletin  SID97-3E.  As Mike Busch says it is The “gold standard” for adjusting fuel flow on fuel-injected TCM engines is a 39-page service bulletin called SID97-3E". 

https://www.avweb.com/ownership/the-savvy-aviator-65-whats-your-fuel-flow-at-takeoff/

Look at Table 9 on page 27 of 38.

https://www.victor-aviation.com/pdf/tech-docs/SID97-3E.pdf

Also the IO-550A on the Missile has an altitude compensating fuel engine driven fuel pump (Auto-lean).  Look at Section 7-2.3.3. IO-550 Altitude Compensating Fuel System Flight Check in the overhaul manual.  The Auto-lean fuel flow curve is the same as the leaning schedule in SID97-E (See page 7-5..it is in lbs/hr but SID97-3E has both lbs/hr and gph shown)

http://www.softoutfit.com/static/refs/io550overhaul.pdf

At sea level the fuel flow should be set to 25.6 gph. (at its max).  At 1,000 ft. elevation where you are taking off you should be seeing 25.4 gph.  You should not need to run the electric boost during climb.  The Auto-lean is "set and forget" when you are in a full power climb.  When you are at 8,500 ft. wide open at 2,700 RPM and full rich you should see approx. 20.3 GPH.  Remember with the Missile you have the air induction which adds about 0.5 PSI to the manifold pressure when you are at speed (or about 1,000 ft. improvement when looking at engine/fuel performance curves).  That also assumes that your top cowl fits tightly against the air filter box without any leakage.

The factory TCM injectors that came with the engine in the Missile STC seem to be quite well balanced and uniform.  With the tight cowling it is typical to fight cylinder temps of 400F or high oil temperatures during summer take offs especially  here in the hot Gulf coast.  You just have to balance climb, speed and temperature.  - sometimes shallower climb with greater airspeed - worst case pause the climb for increased speed/engine air cooling at reduced power.  Your EGT's look about 75 F high. I typically run 75 F ROP.  What do you see for Peak temps?  How does your EDM compare to the original factory analog temp sensor (which has to remain per STC and in my experience is very accurate and a good average to go by)?  Perhaps your injectors need cleaning.  That might explain some of the variation.

More info on auto-lean at end of article. http://www.kellyaerospace.com/articles/ContinuousFlow.pdf

Edited August 18, 2020 by 1980Mooney

[Missile=Awesome]

2 hours ago, 1980Mooney said:

You appear to be flowing way too much fuel.  The Missile STC has an IO-550A.  There are currently 11 versions of IO-550 most with different fuel flow profiles and the profile above doesn't designate or match anything.

You need to be looking at TCM service bulletin  SID97-3E.  As Mike Busch says it is The “gold standard” for adjusting fuel flow on fuel-injected TCM engines is a 39-page service bulletin called SID97-3E". 

https://www.avweb.com/ownership/the-savvy-aviator-65-whats-your-fuel-flow-at-takeoff/

Look at Table 9 on page 27 of 38.

https://www.victor-aviation.com/pdf/tech-docs/SID97-3E.pdf

Also the IO-550A on the Missile has an altitude compensating fuel engine driven fuel pump (Auto-lean).  Look at Section 7-2.3.3. IO-550 Altitude Compensating Fuel System Flight Check in the overhaul manual.  The Auto-lean fuel flow curve is the same as the leaning schedule in SID97-E (See page 7-5..it is in lbs/hr but SID97-3E has both lbs/hr and gph shown)

http://www.softoutfit.com/static/refs/io550overhaul.pdf

At sea level the fuel flow should be set to 25.6 gph. (at its max).  At 1,000 ft. elevation where you are taking off you should be seeing 25.4 gph.  You should not need to run the electric boost during climb.  The Auto-lean is "set and forget" when you are in a full power climb.  When you are at 8,500 ft. wide open at 2,700 RPM and full rich you should see approx. 20.3 GPH.  Remember with the Missile you have the air induction which adds about 0.5 PSI to the manifold pressure when you are at speed (or about 1,000 ft. improvement when looking at engine/fuel performance curves).  That also assumes that your top cowl fits tightly against the air filter box without any leakage.

The factory TCM injectors that came with the engine in the Missile STC seem to be quite well balanced and uniform.  With the tight cowling it is typical to fight cylinder temps of 400F or high oil temperatures during summer take offs especially  here in the hot Gulf coast.  You just have to balance climb, speed and temperature.  - sometimes shallower climb with greater airspeed - worst case pause the climb for increased speed/engine air cooling at reduced power.  Your EGT's look about 75 F high. I typically run 75 F ROP.  What do you see for Peak temps?  How does your EDM compare to the original factory analog temp sensor (which has to remain per STC and in my experience is very accurate and a good average to go by)?  Perhaps your injectors need cleaning.  That might explain some of the variation.

More info on auto-lean at end of article. http://www.kellyaerospace.com/articles/ContinuousFlow.pdf

Thanks for input. My A&P agrees with you. Not sure I agree with your way high fuel flow assessment. We are 26-26.5gph from 870’-1000’. I am cruise climbing at 150-160 knots (about 500fpm) and still cracking 400 cylinder temps. That is unacceptable and doesn’t reflect a high full power fuel flow. Other Missile drivers are saying 27.5 minimum and 28 better...I am just seeking information. We have gami’s...original is analog of course and is in line with edm830. Injectors pulled and cleaned 50 hours ago. Have not noticed pre lean fuel flow at 2700rpm before leaning. Egt’s were 15lop with 12.2gph

[gsxrpilot]

What RPM are you using in the climb? I'd try more fuel and less RPM. I've found that a reduction of 50 to 80 RPM in the climb makes a difference in temps.

 

[Niko182]

Id up that from 26gph to about 28.5GPH. thats a minimum. 26 GPH is way to low. As far as EGTs go, they don't mean shit. You need to find out what you peak EGT is and go from there. The number value doesn't tell you anything. The difference from peak to what value you're seeing, tells you everything.

[carusoam]

yes.
 

So...

An O1 will use near 25gph departing at SL, 2500 rpm...

An O3 at the high end of the STC uses about 27gph, 2700 rpm...
 

Anyone wanting To climb out at full power will ask for more FF...

Some FFs have been documented anywhere from 28 to 30...

There is an excellent review of the Screamin’ Eagle that makes an interesting read...

Getting the STC updated to reflect these changes would be nice.....

Use caution with too high FF... power gets reduced quickly running too rich...

across the range of Mooneys... T/O FF is often 2X the cruise FF, roughly speaking...

PP thoughts only, stuff read around here...

Best regards,

-a-

[kortopates]

The Rocket Engineering STC is the authority for setting your max FF, its possible they would point to TCM for the IO-550-A in which case TCM M-0 becomes the authority. What does Rocket say for your max FF at 2700 and sea level MAP? Isn't it higher than TCM's spec for the -A? 

Personally I would want to see EGTs at takeoff power to see if the mixture is currently too lean - EGTs are valuable when you know how to use them. But if for example, they're 1300+, no problem adding another GPH.

In climb, because you do have the altitude compensating fuel pump, then its important to verify the fuel scheduling in climb to make sure that is working properly. Here is the chart for your engine.

If for example your max FF is at 27.4 GPH that corresponds to 159.7 lbs (5.83 lbs/gal) on the chart below and you'd have to draw another line displaced off the TCM curve for your engine.

Edited August 18, 2020 by kortopates

[Missile=Awesome]

19 minutes ago, kortopates said:

The Rocket Engineering STC is the authority for setting your max FF, its possible they would point to TCM for the IO-550-A in which case TCM M-0 becomes the authority. What does Rocket say for your max FF at 2700 and sea level MAP? Isn't it higher than TCM's spec for the -A? 

Personally I would want to see EGTs at takeoff power to see if the mixture is currently too lean - EGTs are valuable when you know how to use them. But if for example, they're 1300+, no problem adding another GPH.

In climb, because you do have the altitude compensating fuel pump, then its important to verify the fuel scheduling in climb to make sure that is working properly. Here is the chart for your engine.

If for example your max FF is at 27.4 GPH that corresponds to 159.7 lbs (5.83 lbs/gal) on the chart below and you'd have to draw another line displaced off the TCM curve for your engine.

I will need to look in POH for any info and “it” is in the plane.  There is zero discussion in the STC info about max fuel flow for Missile.

[Missile=Awesome]

23 minutes ago, carusoam said:

yes.
 

So...

An O1 will use near 25gph departing at SL, 2500 rpm...

An O3 at the high end of the STC uses about 27gph, 2700 rpm...
 

Anyone wanting To climb out at full power will ask for more FF...

Some FFs have been documented anywhere from 28 to 30...

There is an excellent review of the Screamin’ Eagle that makes an interesting read...

Getting the STC updated to reflect these changes would be nice.....

Use caution with too high FF... power gets reduced quickly running too rich...

across the range of Mooneys... T/O FF is often 2X the cruise FF, roughly speaking...

PP thoughts only, stuff read around here...

Best regards,

-a-

Agree with ALL of this -a-.  We have a 2700 redline and 26.5 “ain’t getting it done” for cylinder cooling in climb...I am 100% certain that we are NOT flowing “too much fuel” at take off power in our Missile as currently configured...Appreciate the input.

[Missile=Awesome]

1 hour ago, gsxrpilot said:

What RPM are you using in the climb? I'd try more fuel and less RPM. I've found that a reduction of 50 to 80 RPM in the climb makes a difference in temps.

 

Might explore this after exploring MORE fuel option Paul.  Thanks.

[kortopates]

I will need to look in POH for any info and “it” is in the plane.  There is zero discussion in the STC info about max fuel flow for Missile.

If not in the POH AFMS, Rocket published something in form of maintenance instructions with the STC. You should be able to get that info from them - they no longer provide it on their website - just jet prop stuff.


Sent from my iPhone using Tapatalk

[carusoam]

For the Screamin’ Eagle... Rocket engineering has a FF range printed in pph in the STC...

RE is awesome with regards to their documentation...

Check the Missile docs carefully, it is probably in there somewhere...

Best regards,

-a-

[Guest]

9% of rated horsepower would be a typical number per TCM, however they sell cylinders everyday.  I’d turn it 1 gph beyond even that minimum number as a staring point.  

The current SID 97-3G now refers to the current overhaul manual for procedures and limits for many engines.

Clarence

Edited August 19, 2020 by M20Doc

[Missile=Awesome]

I will give Rocket Engineering a call.  I see what TCM is saying regarding IO550, but Busch says if Gami’s and aftermarket configurations there may be differences.  I think the Missile is one of those based on others fuel flow setting and reduced cylinder temps in climb.  My A & P stated that he should NOT increase above 27.5 based on TCM’s criteria...Hoping Rocket has something I am missing.  I just can’t imagine that more fuel wouldn’t address some of the temps in climb...

[Missile=Awesome]

Just now, M20Doc said:

9% of rated horsepower would be a typical number per TCM, however they sell cylinders everyday.  I’d turn it 1 gph beyond even that minimum number as a staring point.  

The current SID 97-3G now refers to the current overhaul manual for procedures and limits for many engines.

Clarence

27 is 9%.  That was the number I was thinking of too Clarence “28”.  MUCH APPRECIATED on your input.

EVERYONE Thank you!

[Guest]

Just now, Missile=Awesome said:

I will give Rocket Engineering a call.  I see what TCM is saying regarding IO550, but Busch says if Gami’s and aftermarket configurations there may be differences.  I think the Missile is one of those based on others fuel flow setting and reduced cylinder temps in climb.  My A & P stated that he should NOT increase above 27.5 based on TCM’s criteria...Hoping Rocket has something I am missing.  I just can’t imagine that more fuel wouldn’t address some of the temps in climb...

A little extra fuel at max power is cheap insurance for your cylinders.  The max fuel value is only useful if the flow transducer is accurate, otherwise use a calibrated pressure gauge to measure meter fuel pressure at the flow divider test port.

Clarence

[1980Mooney]

1 hour ago, M20Doc said:

The max fuel value is only useful if the flow transducer is accurate, otherwise use a calibrated pressure gauge to measure meter fuel pressure at the flow divider test port.

Clarence

That was my thought also.  The "K" factor in the JPI Fuel Scan is adjustable.  Since this is a new to you Missile the calibration may be off or never accurately checked.  Another way to check is fill the tanks to the lips (including outer tanks if it has Monroy's), fly it and return to the same pump and fill again.  Compare the JPI totalizer to the pump.  You can  go into the JPI menu and adjust the K factor accordingly. 

I am a bit surprised at the variation in EGT's and in the CHT's excluding #6 up front considering that these are GAMI.  #5 looks hot.  If not the injector it could be an exhaust valve leak giving you the 90 deg. F EGT variation.  My TCM factory injectors have always had a tight EGT spread. Carusoam commented on the same experience  in a thread 5 years ago... 

 

Also make sure that the flexible baffle seal on the front of the engine is turned upwards into the lower cowling.  If it is turned downwards, especially if you have old seal and some engine mount droop,  both the sealing will be poor and the airflow pressure will push the seal further away from the lower cowl.  This allows some cylinder cooling air to bypass and go directly under the engine.  If the seal is turned up, the airflow pressure will push it tighter into place.  I have to remind my A&P every time they decowl the engine.

That said, Missile's run hot in extended hold/taxi, take-off and climb....especially in the South.  It may make some uncomfortable but I have been flying my Missile 19 years without any major issue.

[Missile=Awesome]

13 hours ago, 1980Mooney said:

That was my thought also.  The "K" factor in the JPI Fuel Scan is adjustable.  Since this is a new to you Missile the calibration may be off or never accurately checked.  Another way to check is fill the tanks to the lips (including outer tanks if it has Monroy's), fly it and return to the same pump and fill again.  Compare the JPI totalizer to the pump.  You can  go into the JPI menu and adjust the K factor accordingly. 

I am a bit surprised at the variation in EGT's and in the CHT's excluding #6 up front considering that these are GAMI.  #5 looks hot.  If not the injector it could be an exhaust valve leak giving you the 90 deg. F EGT variation.  My TCM factory injectors have always had a tight EGT spread. Carusoam commented on the same experience  in a thread 5 years ago... 

 

Also make sure that the flexible baffle seal on the front of the engine is turned upwards into the lower cowling.  If it is turned downwards, especially if you have old seal and some engine mount droop,  both the sealing will be poor and the airflow pressure will push the seal further away from the lower cowl.  This allows some cylinder cooling air to bypass and go directly under the engine.  If the seal is turned up, the airflow pressure will push it tighter into place.  I have to remind my A&P every time they decowl the engine.

That said, Missile's run hot in extended hold/taxi, take-off and climb....especially in the South.  It may make some uncomfortable but I have been flying my Missile 19 years without any major issue.

Good suggestion on confirming fuel flow.  Have filled to tabs and flown and filled and transducer was +-<gallon.  Engine mounts replaced <500 hours.  The seal I will 100% check as I wasn’t aware of this...THAT could be HUGE.  Thanks.

Edited August 19, 2020 by Missile=Awesome

[Seth]

Sorry for the late arrival to the party and thanks for contacting me directly Scott.

As a fellow Missile owner - YES - 1 gallon will make a difference. Both myself (N1165N) and the former Missile owner of 888 (letters or something different - trying to remember - had our engines set up to factory specs - and it wasn't enough cooling flow on takeoff. There is a thread here on Mooney Space that points that out. You want at least 27.5 GPH on Takeoff, preferably in my experience 28 GPH, or you risk high cylinder temps and cracking of cylinders. In Cirrus Aircraft with a 310 HP IO550, the max takeoff fuel flow is 29.9 GPH to keep the engine cool.

After taking ownership in 2011, I had the engine overhauled. 100 hours later two cylinders cracked. Once we got new cylinders on fully covered by warranty and I split the cost with the engine shop on the other four cylinders, I researched this a lot and found the fuel flow had to be higher on takeoff to avoid this sort of problem. 

Disclaimer - I'm NOT an A&P and worked with my shop to get the adjustments required to ensure the proper fuel was flowing for cooling.

There are two screws that adjust the fuel flow on the IO550 set up in the Missile. One adjusts the top end full power flow and one adjusts the idle flow. They are supposed to be independent of each other but they do affect each other. There is a balance - if you get the full power setting screw set properly, it can effect the idle flow which will cause flooding and your engine will burble and then quit on you. Happens after landing or during low idle. So you to make sure the engine is flowing enough fuel at takeoff (min 27.5 - I like closer to 28 or 28.5 and does not sputter and flood/shut off at idle).

On takeoff and climb out my cylinders stay in the 380 range. On hot days or after sitting for a while in line getting hot before takeoff, one or two cylinder will climb to 392 on takeoff but most stay in the low 380s or even 378. Rarely do I ever see anything with a 400 in front and that's when I did something wrong.

Remember, our mixtures are altitude compensating in the Missile. You can always reduce fuel by pulling the mixture out but can't add any extra in (technically you can by running the boost pump - another idea until you get this sorted).

I also tend to aggressively lean during ground ops/taxi.

Good luck!

-Seth

[Seth]

On 8/18/2020 at 10:04 AM, Missile=Awesome said:

Our IO-550 in our Missile is flowing 26 Gallons at Full Power on Take Off.  Photos don’t show climb Cylinder Temps or EGT’s (These are cruise) and there is NOT a problem with the volts, well there is, but it is in the pin for the 830...Not an actual voltage problem...Here is question:

Will One Gallon (Getting Max Fuel Flow at full take-off/climb power make a significant difference on cylinder temps.  The missile is tightly cowled and has no cowl flaps so doing a cruise climb is preferred (still see 700-1000fpm), but we are seeing some temps in climb approaching and ticking above 400.  EGT’s are also significantly higher than I would expect.  (This is at 8500’).  Sea level is 27.4gph on IO-550.  We are going out of <1,000’ and seeing 26 to 26.5 max on full power fuel flow.  We are running boost pump in climb and still seeing elevated cylinder temps...

Appreciate input.

We had to set the FF higher at sea level to keep cylinder temps around 380. Bump it to 28gph to 28.5 gph.

-Seth

[mike_elliott]

4 hours ago, Seth said:

We had to set the FF higher at sea level to keep cylinder temps around 380. Bump it to 28gph to 28.5 gph.

-Seth

When you can hear the fuel rushing to the engine over the sound of the engine, its probably too high

[Missile=Awesome]

Just now, mike_elliott said:

When you can hear the fuel rushing to the engine over the sound of the engine, its probably too high

Humor?

[mike_elliott]

43 minutes ago, Missile=Awesome said:

Humor?

Not if you have a Cherokee 400