Pireps on firewall forward HP + STC

[Sandman993]

Can’t bang out everything she can do yet... at 25 hrs, she’s still got a bit to go until I can ask all the ponies to gallop. At this juncture, im trying to stay around 24” , 2450 2500 and 11.x gph to stay below 380  Cht’s...at or below 7.5 altitude. 

Part of the reason for the hi comp pistons is higher altitude flights with more ponies at a given altitude. Making more horse power up there, where the air is thin and less drag made sense, even to me. I know there are turbos to buy for this sort of goal, but there’s the maintenance and operating cost notion to deal with...didn’t turn this 201 into a F18, but I could say this 201 is awake.

70% of stock 200hp is 140hp

70% of horse power plus 225hp is 157hp and change.

there are always bigger faster fish... but they don’t burn 10.x gph rop.

[jetdriven]

3 hours ago, Sandman993 said:

 

70% of stock 200hp is 140hp

70% of horse power plus 225hp is 157hp and change.

there are always bigger faster fish... but they don’t burn 10.x gph rop.

Their website says “up to 25hp” but has anyone ever actually dyno’d one of these engines?  25 Hp is 12% more HP, but it’s 14% more compression and I’m not sure it’s linear. 

[carusoam]

Sandman,

What was the break in procedure like?

• full throttle
• mixture in
• Alternating rpm every 15 minutes or so?
• Stay low 
• Cold days if possible

Fun flights near the beach with a second person on board....

Best regards,

-a-

[Sandman993]

This is an STC and while all engines are different, the basic goal is 25hp increase. They do have a dyno test stand at the facility...and folks that send their engines in for overhauling will get a certain amount of break-in on the stand. I chose option b, so my overhauled engine went straight onto the firewall and a company test pilot did the honors for the first 1.5 hrs. Of course, everything went fine, but not sure I would trade jobs with that fella. In theory, this mod should increase hp output by 25hp + or -. I was there and watched the test flights... it’s in FlightAware.

The break-in procedure is straight forward. Cht’s Under 400 and fly long legs over 2hrs at 60 to 65% power settings at or below 7,500’ for up to 50 hrs. As the cylinders seat, they will begin to transfer heat better to outer cooling surfaces so in essence, temperatures dictate power settings. Mines at 25hrs and break-in is almost complete. Soon i’ll Be able to stretch her legs (cool pun) and see what she’s hiding. But she’s already faster than before.

[carusoam]

Sandman,

Ever look into adding a TN?

wondering if the STC for one keeps away from the STC of the other...

Technically, air cooling becomes a bit more challenging as the air density declines with altitude...

There are a few people running TNs on both O360s and IO360s around MS...

Looks like a lot of TBO fear goes away with decent instrumentation....

Thanks for sharing your details.

PP thoughts only, not a mechanic...

Best regards,

-a-

[Sandman993]

It really is about the gauges isn’t it? I wonder how anyone can manage one of these very expensive engines without knowing what’s going on inside them. 

TN is a great idea, but I’m already funding an overhaul... the turbo notion is just out of reach for me. To add one to a solid engine, might be a different story. Now, I’ve painted myself past the door since hi comp pistons and turbos are not compatible. As you probably know, the high output turbo engines typically have compression down in the 7’s... if I tried that with 10’s, I think there would be a Fukushima moment coming to an airspace near me.

if I had it all to do over again, I could see wanting a 252... but In the beginning, I didn’t realize where this journey would lead. Am sure we can all remember moving up to a 201 from something... for me, it was a Grumman Cheetah...a fulfilling moment... I just had to figure out how to drive what was then, a new and challenging, complex platform. Over time and lots of training, the complex little ship revealed itself and for the most part, her mystical vail was lifted. In other words, we always want for more, once we’ve caught up to something... flying is no different. I keep telling myself, it’s the economy of the 201, along with her good looks that is it’s true, truth. In the certified world, there’s not much out there to compare. Of course, you can buy an experiment platform... built somewhere, in some garage by a stranger.

[carusoam]

Sand...

What I was thinking with the TN...

You can keep the same 225hp all the way up into the high teens(?)...

So not so Fukushima as a highly compressed dragster at the 1/4mile near you....

Just not running out of power as the air thins out... never more than 225hp...

Improved efficiency the higher you can fly, while still maintaining a comfy 65% bhp.... Running LOP

 

This also is an interesting issue during really cold days... when atmospheric pressure gets pretty high.  The DA can drop a couple of thousand ft below sea level...

Does your STC have a complete power chart?

Does it have a recommendation for really high natural MPs?

The Original mooney manuals didn’t cover the high MPs found around the north east in the middle of winter... 

There are a few pictures of cracked cylinder heads around here. Possibly related to really high ICPs...(?)

Something to keep in mind On really cold days...

 

As for the 252... it is so expensive because... it is so well developed.... and delivered...

I went the route of simply adding more displacement...  had to change planes to do that...

Best regards,

-a-

[Sandman993]

Yeah, the digital tach had to be sent off to be re-calibrated...which means the rpms have some new operating ranges. Also, the old badges have been replaced with exactly what you were writing about...it’s pretty rare in my part of the country to have minus density altitude, but it does happen... plus you’ll need this information while on away trips. Not a big deal, just fly the numbers with a little less MP so the engine doesn’t over pressure itself.

I have a lot to learn going forward... finding the new sweet spots and learning new parameters. The ships baffling is right so I’ll get an honest assessment on how to manage heat. I do like the new takeoff power... still surprises me every time.

 

[jetdriven]

What do you mean new operating ranges? Isn’t the tach 2700 RPM redline and a yellow arc from 1450-1900 or similar? 

[Sandman993]

The redline remains at 2700... but the operating ranges change significantly enough that the tach needed to be messed with. As those of us with digital tachometers know, there’s a bit of a light show when we are out of bounds. I love my digital tach. A cable tach would just get some new badges.

[jetdriven]

I do not understand what you mean. It’s either a green band or a red light when you exceed 2700 RPM. What else constitutes this “light show” ?

Edited June 19, 2018 by jetdriven

[AaronDC8402]

When we switched from the Firewall Forward cam and pistons STC back to the Lycoming standard pistons and cam, there were no changes to our analog or digital tach. Operation in the yellow band seemed the same between the two engines. 

 

 

[Sandman993]

I’ll get you guys the numbers next time I’m looking at the new placards. It changes... I don’t know if it’s symbolic or important, but there is a shift in parameters. The analog tachometer is just that. The digital unit is programmable to throw a light when you over speed or if you get the rpms in a place with low mp at same time... has to do with internal crankshaft balance weights which have been overhauled with the rest of the engine.

[320KPH]

So not so Fukushima as a highly compressed dragster at the 1/4mile near you....

 

but those dragsters are running methanol or nitro fuel...

[kellym]

On 3/11/2018 at 2:09 PM, Sandman993 said:

25 hp added to 200 is more like 12+% increase.

altitude is a horsepower bandit... high da’s are too. An extra 25 would certainly be welcomed trying to get off a 5,000+ ft msl runway! Ask anyone.

to that other fellas mention of variable timing... I checked in via email with an electronic ignition outfit to pose the question of when they might offer that to our certified birds... the response by a fella named klaus was, buy an rv 10, which would make sense except I don’t want an airplane that was made in someone’s garage by a stranger. Besides, I like my magical Mooney.

Just ran across this thread. Those that started on the original Mooney email list know that a 201 with the FF 10:1 pistons had an engine failure on takeoff from Madison for the first Mooney Caravan.  After a couple other unrelated engine incidents, the pilot became known as Black Cloud. 

I've seen this discussion on Cardinal and Mooney lists. The extra horsepower is likely in the 10-15 range, not 25. It is also unavailable at sea level, if you abide by the restrictions in the STC. It will run hotter, because you are making more HP. Reports are typically needing a top at 800-1000 hours unless you are very religious about keeping CHT down. Yes, you can generate 75% power to higher altitudes, and once you have a few thousand feet you can out climb a stock engine. If a pilot is out climbing you from sea level, they are not abiding by the STC. The MP limit is to keep you from making more than 200 hp, because that would reclassify the aircraft, and would require a High Performance endorsement to fly. They probably did not test the engine for endurance at above 200 hp either..which would have been required if they allowed it to make more than 200 hp (plus 2% tolerance the OEM has).

Note mentioned in the discussion is what one does when the current 100LL goes away and possibly the replacement does not have as much detonation margin.

[kellym]

On 6/16/2018 at 3:49 PM, Sandman993 said:

This is an STC and while all engines are different, the basic goal is 25hp increase. They do have a dyno test stand at the facility...and folks that send their engines in for overhauling will get a certain amount of break-in on the stand. I chose option b, so my overhauled engine went straight onto the firewall and a company test pilot did the honors for the first 1.5 hrs. Of course, everything went fine, but not sure I would trade jobs with that fella. In theory, this mod should increase hp output by 25hp + or -. I was there and watched the test flights... it’s in FlightAware.

. But she’s already faster than before.

Even if you can produce 225 hp on a dyno, 1. you won't get that on the airframe with muffler and prop, alternator etc. 2 you can't legally use over 200 hp and the MP restriction is supposed to keep you at or below 200 hp. Fact is a J is certified with 200 hp and unless the STC actually addressed a hp increase (I am sure it did not, due to testing costs) you can't use it.

If you choose to cruise at above 150 hp, you will burn more fuel, significantly and the speed gain only increases as something like the square or cube root of added hp.

[ArtVandelay]

It should not run hotter just because it’s producing more horsepower. If it’s more efficient, and my understanding is higher compression is all things being equal, then it should produce less heat. I’m betting all things are not equal.

[kellym]

Just now, teejayevans said:

It should not run hotter just because it’s producing more horsepower. If it’s more efficient, and my understanding is higher compression is all things being equal, then it should produce less heat. I’m betting all things are not equal.

Efficiency is not going to reduce the heat produced. HP=heat.  Better efficiency will turn more of the heat into output, rather than going out the exhaust.

The FF STC has a long reputation of tending to run hot. Yes, you can improve cooling in the baffling, etc. but to make more power, more heat is produced. Whether you improve the cooling, or run at power settings and cowl flap settings to control that will depend on your method of using the engine.

[Sandman993]

Am getting closer to break in... and can say heat management is key, but can use most or all available power on takeoff without exceeding 360ish on cht’s as long as She’s full rich... that works well and gives the bird a chance to build up some speed. In climb, get at or above 120 indicated, everything settles in nicely and the leaning process can begin as appropriate. Oil temp looks good. At this point, she’s pulling away handily from a stock 201. I need my F18 license now! Lol just kidding.

Placard does have some limitations below 1800  pressure altitude...Think you have to adjust mp to 28.5 at 1800pa if memory serves. Don’t have to worry about that in my region until summer is over, but the placards are right there if I wander too far off the reservation.

As for heat management, no reasonable thinking pilot should operate our 200hp 4 cylinder platform without some kind of 4 point engine monitoring gadget (insert fav brand). Stock or modified... it’s just too important to know that critical info. My personal cht maximums are 380 degrees... once I get there and if she’s trending upwards, can take steps to reverse the trend and much prefer 350’s. So if the ship starts using up cylinders, it won’t be because I was being a moron and cooking them.

if I want to cruise at the old speeds, I’m finding that less mp at altitude is required as the prop is able to take a bigger bite without binding the engine.

mines not the only aircraft engine out there with high compression pistons... if they ever do change fuel in my lifetime. Sarc

First and foremost, I’m not trying to recommend that everyone run out and add this stc to their airplanes... originally, was simply making note that the company was being unfairly treated and reviewed by a few folks and parroted by several others. Some of the comments were brutal and I didn’t find the claims to be true in my experience. Quite the contrary.

[jetdriven]

So it’s 75% of 215 or 220hp at altitude instead of 200. So at 75% power it’s 10-15HP more at altitude. Does that really cause these life-changing differences in cruise speed and climb?  

[carusoam]

Sand,

Have you gotten any LOP flights in?

This is where the extra technical efficiency could really show up... and cylinder cooling is pretty awesome too...

all (most possible) fuel is being converted to mechanical energy.  None (least possible) is being used for cooling...

Got some 3 or 4 way speed tests with associated FF for that?

What altitude would make the most sense to benefit the most for the FF STC?

I See what Byron is saying... with N.A. engines... our best cruise speeds are at or near 8k’... and our MP has been reduced quite a bit (35% reduction?)

With 310hp in an O3, the extra hp is great for getting off the ground and in climb... but it is terribly expensive during cruise to use what is available....

Thanks for sharing your data...

 

Best regards,

-a-

[ArtVandelay]

19 hours ago, kellym said:

Efficiency is not going to reduce the heat produced. HP=heat.  Better efficiency will turn more of the heat into output, rather than going out the exhaust.

The FF STC has a long reputation of tending to run hot. Yes, you can improve cooling in the baffling, etc. but to make more power, more heat is produced. Whether you improve the cooling, or run at power settings and cowl flap settings to control that will depend on your method of using the engine.

HP=Energy, the more kinetic energy you can get, the less energy is available or left  over that becomes heat. Better efficiency, results in less heat, more energy delivered to the prop. We measure HP delivered to the shaft. 

High compression can result in bad combustion, which will result in more heat. Or more fuel will give off more heat. More efficienct should produce less heat .

[Sandman993]

On 7/3/2018 at 10:13 PM, jetdriven said:

So it’s 75% of 215 or 220hp at altitude instead of 200. So at 75% power it’s 10-15HP more at altitude. Does that really cause these life-changing differences in cruise speed and climb?  

It’s supposed to be 25 hp and yes it’s more robust. Whatever power it is... there’s just more of it.

The nice thing about my experience with this thread has been the feedback... I appreciate the things y’all have written for input. It stimulates thought. Some here seem like they have a decent handle on these airplanes. Not everyone I run across can say that. To date, have had a good time on the 201 platform and I learn something new almost every flight. Fine tuning ones flight skills can be satisfying albeit hard on the pocketbook. Maybe I’ll see some of you at air venture... 

 

[Sandman993]

Too early for lop flights... I’ll look at that when I get to 50hrs. When She gets above 6,000’ I can see decent cruise numbers at lower power settings and gph down in the high 9’s. 

The only real testing I’ve done since the rebuild is a single flight along side the 201 (same year) I share a hanger with. Before we were evenly matched except for his climb rate was much better. Need to mention that he has a three blade prop. Even now I can’t climb any better than him but can briskly walk away in level flight. I wrote this before in an earlier post. But we set him up at 25 squared and my ship was at 2450 and 24” and our ground speeds were 10kts different. I’ll let you guess which was which. It was remarkable.

[ArtVandelay]

3 blade props are known for slower cruising speeds.
So assuming you weren’t making rated HP on your old engine then I would say the 10 knots can be attributed to:
2 blade prop
New, tuned engine making rated power.
STC HP boost.