Calling Bravo Owners! Performance and FF questions.

[Shadrach]

So I was talking with my hangar neighbor yesterday about the 1999 Bravo he flies (he's an A&P and the corp flight department has one he uses to get other birds in the fleet with MX issues while away from base).

 

Some info he was throwing around yesterday.

 

Full Rich Take off FF is about 31.5GPH

 

Initial climb at gross is about 1000 FPM @ Gross but they keep it around 750FPM to keep CHTs under 450.

 

They usually fly in the mid to high teens at 33" X 2300 leaned to 24.5GPH and see speeds between 190 and 205KTS true.

 

It is a FIKI airplane with 120gal tanks.

 

It has less than 1000lbs useful. With full fuel and TKS tanks it has around 180lbs of payload.

 

 

I mention all of the numbers above, because his FF and speed numbers do not make sense to me.  I'm at a loss as to how they are puking that much fuel through the engine in cruise.  With those kind of numbers a Bravo with standard tanks (89gal tanks) would be a 3 hour airplane. 

 

Is there anyone here with similar experience?  To my way of thinking, in cruise this airplane should be burning closer 17.5GPH after leaning.

[carqwik]

If he was paying for the plane, he wouldn't operate it like that. 

[Awful_Charlie]

Sorry, those numbers sound way off to me.

 

My take off FF is around 28-29 GPH, until I pull it back to 34/24 when it drops to 25, then about 22-23 with a tweak of the red. 1000fpm and 120KIAS is about right if lightly loaded, otherwise it can be 600-700 at MTOW

 

1000lbs useful sounds good, and yes, 120usable is going to consume a lot of that, and you lose another 58lbs for full TKS. I don't have the Monroys, so don't have that option, b ut it's not often I would want it, certainly not often enought to make it worth the 30-40 hours of install.

 

I don;t have a problem keeping CHTs way under 450, normally I keep them under 400, but the occasional slip see it over that but under 410 in the climb, as to be expected it it a IAS/FF/OAT/Altitude/Cowl flap setting compromise.

 

For cruise, I rarely use setting over 15GPH, but there is a thread somewhere else about high speed cruise, but 21 will bust the 200KTAS in the high teens of FLs.

 

On the whole, mine is pretty close to book, it seems better in the TAS, but worse in the take off distance, maybe a previous owner got it rigged bang on where I'd like it!

[M016576]

So I was talking with my hangar neighbor yesterday about the 1999 Bravo he flies (he's an A&P and the corp flight department has one he uses to get other birds in the fleet with MX issues while away from base).

Some info he was throwing around yesterday.

Full Rich Take off FF is about 31.5GPH

Initial climb at gross is about 1000 FPM @ Gross but they keep it around 750FPM to keep CHTs under 450.

They usually fly in the mid to high teens at 33" X 2300 leaned to 24.5GPH and see speeds between 190 and 205KTS true.

It is a FIKI airplane with 120gal tanks.

It has less than 1000lbs useful. With full fuel and TKS tanks it has around 180lbs of payload.

I mention all of the numbers above, because his FF and speed numbers do not make sense to me. I'm at a loss as to how they are puking that much fuel through the engine in cruise. With those kind of numbers a Bravo with standard tanks (89gal tanks) would be a 3 hour airplane.

Is there anyone here with similar experience? To my way of thinking, in cruise this airplane should be burning closer 17.5GPH after leaning.

In max AB, the super hornet went through 2 gallons a second... Per engine. That's puking fuel....

[AndyFromCB]

24.5 at 2300/33 is a bit much. Mine eats about 23 at 34/2400 leaned back to 1650TIT, or 26 full rich mixture. BTW, this setting is:

 

-cruise climb, at full rich, about 800fpm at gross at 120knots, never seen more than 410CHT at this setting

-max cruise, at 1650TIT, will easily hit 210knot at this setting at FL180

 

You can get it down to 20 or so if you're willing to run 1750TIT.

 

If you climb at full power, 38/2550 and 105knots, you'll see about 1400fpm at gross but it can overheat. The funny thing I've noticed that if I'm cruise climbing at 34/2400 and 120 and see my CHT hit 410, all I have to do is go full power and the CHT will actually drop due to additional fuel.

 

And yes, Bravo is a 3 hour IFR aircraft but you cover 600nm in these 3 hours, so it's not bad but I almost never take off with more than 70 gallons on board due to my rather sizable behind.

 

The only thing that sucks about the Bravo, as far as I am concerned is lack of heat in the foot wells. I wear really thick socks when it's -40C outside. The rest of cabin is nice and warm but it can be below zero in the foot wells.

 

As to cruise, I cruise at about 28/2300, at about 15GPH and hit about 185 mid teens.

[Shadrach]

If he was paying for the plane, he wouldn't operate it like that.

That is a running joke amongst us. He's in the process of getting checked in one their Conquests. :-/

[Shadrach]

24.5 at 2300/33 is a bit much. Mine eats about 23 at 34/2400 leaned back to 1650TIT, or 26 full rich mixture. BTW, this setting is:

-cruise climb, at full rich, about 800fpm at gross at 120knots, never seen more than 410CHT at this setting

-max cruise, at 1650TIT, will easily hit 210knot at this setting at FL180

You can get it down to 20 or so if you're willing to run 1750TIT.

If you climb at full power, 38/2550 and 105knots, you'll see about 1400fpm at gross but it can overheat. The funny thing I've noticed that if I'm cruise climbing at 34/2400 and 120 and see my CHT hit 410, all I have to do is go full power and the CHT will actually drop due to additional fuel.

And yes, Bravo is a 3 hour IFR aircraft but you cover 600nm in these 3 hours, so it's not bad.

The only thing that sucks about the Bravo, as far as I am concerned is lack of heat in the foot wells. I wear really thick socks when it's -40C outside. The rest of cabin is nice and warm but it can be below zero in the foot wells.

As to cruise, I cruise at about 28/2300, at about 15GPH and hit about 185 mid teens.

Interesting. In my mid body, the rear passengers outside legs are the cold spot. You can get the whole cabin warm (will put plenty of heat into the footwells), but risk cooking the front seaters if you fully open the heat exchanger and center vent. It's bee much better since I insulated it.

[Shadrach]

In max AB, the super hornet went through 2 gallons a second... Per engine. That's puking fuel....

It's all relative I suppose...in either case, it's good to have someone else paying for fuel!

[jlunseth]

If the prior owner operated it at 450 CHT's on a regular basis I would not buy it, or if I did I would anticipate having to do at least a top overhaul right away.  I know the POH for the turbocharged engines has a high CHT limit (the limit on my 231 is 460), but the cylinders do not last long at that temp.  I would strive for max 380 at cruise, and would not let the temp go over 420 for any reason, and then it should be short duration. 

[AndyFromCB]

If the prior owner operated it at 450 CHT's on a regular basis I would not buy it, or if I did I would anticipate having to do at least a top overhaul right away.  I know the POH for the turbocharged engines has a high CHT limit (the limit on my 231 is 460), but the cylinders do not last long at that temp.  I would strive for max 380 at cruise, and would not let the temp go over 420 for any reason, and then it should be short duration. 

 

Yeap, even though the lycoming has oil cooled guides, which IMHO makes it the best high alitude engine ever out in a Mooney, 450 is just nuts. Unless you're leaving Aspen, Telluride or Jackson Hole, if the temp starts creeping up, lower the damn nose. I've never seen over 410, even during break-in and it gets pretty damn hot here in Iowa.

[kmyfm20s]

I usually get "Turbo Envy" on my long distance mountain trips. I think this thread has taken care of that:)

[AndyFromCB]

I usually get "Turbo Envy" on my long distance mountain trips. I think this thread has taken care of that:)

 

Don't ever fly one then ;-) Because first time you take off and see 1000fpm vs 200fpm departing from a mountain airport, you'll never go back. You just don't look at the pump receipts ;-) And in all honestly, I can go a bit faster than a J on not much more fuel. I see 155knots all the time at 13gph at about 24"/2350 and peak TIT of around 1600.

[gjkirsch]

I have 120 gallon tanks and TKS.  With full fuel and TKS, I have under 300 pounds of useful load.  I lean in climb to 1500 TIT which is about 25 GPH.  My cylinder temps have never hit 400 in climb and run 360 in cruise.  At 120 knots indicated, I am at 600 FPM at gross and standard temps.  If its colder, it climbs better.  At light weights and low temps, I have seen over 1500 FPM.   I cruise at 30/2400 and 19 GPH which gives me a 1590 TIT.  180 knots at 10,000 to 205 knots at FL210.  Have not been higher

[Shadrach]

Don't ever fly one then ;-) Because first time you take off and see 1000fpm vs 200fpm departing from a mountain airport, you'll never go back. You just don't look at the pump receipts ;-) And in all honestly, I can go a bit faster than a J on not much more fuel. I see 155knots all the time at 13gph at about 24"/2350 and peak TIT of around 1600.

I've had my lowly F model to density alt above 16k and have never seen less than 350 per minute. That being said, I see the appeal. I'm not thinking of buying it. My NA 4 banger fits my mission much better. I would not exactly call 155kts on 13gph "J" model performance, a properly rigged J will do 155Kts and more on less than 13gph, but it's not too shabby nonetheless.

If I had an unlimited budget, I'd Turbo Normalize the F and clean up the airframe a bit. I have 1059 useful right now which means I can go 500NM with 200lbs per seat (using round numbers) and still have ~1hour reserve.

Still the Bravo is an impressive AC.

[johnggreen]

My 8 years operation of the Bravo gave me comparable numbers to the above posters.  I generally flew at 2200/30" in the mid teens, burned 14-15 gallons, 1650 TIT or below.  The only thing that I can't "compare" to is the CHT numbers.  Most of you fellows really need to look at your baffling because your numbers are way over what I ever saw.  Even in climb, I would rarely see at cylinder over 350.  At cruise, using the numbers I just gave, 300 degrees was the average.  Yes, I had an engine monitor.  The ship's gauge was always 50+ degrees higher than the engine monitor and we could never figure out why.  As to useful load, my Bravo was 875 with full TKS.  It was hard not to overload by a "few" pounds at times, but rarely more than 75.  I never worried about the airframe, but the gear was another matter.  If the Mooney has a weak spot, the gear was it which, IMO, is a direct cause of so much of an issue with leaking tanks.

 

Bravo: one hell of a capable airplane.

 

Jgreen

[M016576]

I'm thinking that the 450 in the OP is a typo and should read 350. Hard to believe CHT's would hit 450 (redline): you'd have to work to do that, I think.... Unless you've got detanation going on....

[M016576]

Don't ever fly one then ;-) Because first time you take off and see 1000fpm vs 200fpm departing from a mountain airport, you'll never go back. You just don't look at the pump receipts ;-) And in all honestly, I can go a bit faster than a J on not much more fuel. I see 155knots all the time at 13gph at about 24"/2350 and peak TIT of around 1600.

I'm trying to justify a Bravo right now, versus my current J model, mainly for the TKS. Even up to 12.5 density altitude, I can sustain 500fpm climb at max gross weight in the J.

My mission is typically ~ 330nm. I burn 20 gallons for that in about 2:15. (Cruise @ 8500-11500, typical fuel burn is ~8.5gph, 155KTAS). With a good tailwind, I've made that trip in 15 gallons. I figure with a bravo I could do the trip in 1:40 and burn 30 gallons. So for a 35 minute time savings, I'd be paying 30-50% more in fuel. But on those days where it's snowing or icing conditions prevail, I could actually fly the mission. And that makes the extra fuel burn worth it (in the winter). Really, what I need is a J and a Bravo ;-). I wish!

[Shadrach]

I'm thinking that the 450 in the OP is a typo and should read 350. Hard to believe CHT's would hit 450 (redline): you'd have to work to do that, I think.... Unless you've got detanation going on....

It's absolutely not a typo. CHTs of 450 degrees may be unheard of on a well baffled NA 4 banger, but are entirely "achievable" on a larger displacement tightly cowled TCd 6 with a turbo eminating heat inside the cowling. Especially if the baffling is poorly installed.

[jlunseth]

Agreed you can make 450 or more in a big hurry if your baffling is bad, the OAT is high, and you make the mistake of all mistakes with a turbo, which is to lean for climb because you read somewhere that is the way to do it.  That works for NA engines.  Leaning for climb is not a great idea in a turbo.  I have talked to pilots who say they can do a cruise climb and keep the temps low while leaning a turbo, but that is a shallow climb at a high airspeed.  It is way better to open the cowl flaps and run the engine at 100% where the fuel flow will be boosted by the fuel distribution system, so the temps will stay cool in the engine.  I will occasionally do a climb of a couple thousand feet (meaning two thousand or less at a cruise power setting, but not a sustained climb to a high cruising altitude. 

 

If you want to justify a Bravo, think tailwinds aloft.  On a typical west to east trip they can be anywhere from 25-75 knots and occasionally you get some real gales.  So take the Bravo's TAS, say its 190, and add 75, you are doing low turboprop speeds.  The return flight will need to be lower, but that would be true regardless of the engine type.  My best flight ever in my lowly 231 (normally about 165-170 TAS in the Flight Levels), was an average cruise of 240+ knots.  Peoria to Maryland in under two hours.  You do not need a very big fuel tank for that. 

[M016576]

Agreed you can make 450 or more in a big hurry if your baffling is bad, the OAT is high, and you make the mistake of all mistakes with a turbo, which is to lean for climb because you read somewhere that is the way to do it. That works for NA engines. Leaning for climb is not a great idea in a turbo. I have talked to pilots who say they can do a cruise climb and keep the temps low while leaning a turbo, but that is a shallow climb at a high airspeed. It is way better to open the cowl flaps and run the engine at 100% where the fuel flow will be boosted by the fuel distribution system, so the temps will stay cool in the engine. I will occasionally do a climb of a couple thousand feet (meaning two thousand or less at a cruise power setting, but not a sustained climb to a high cruising altitude.

If you want to justify a Bravo, think tailwinds aloft. On a typical west to east trip they can be anywhere from 25-75 knots and occasionally you get some real gales. So take the Bravo's TAS, say its 190, and add 75, you are doing low turboprop speeds. The return flight will need to be lower, but that would be true regardless of the engine type. My best flight ever in my lowly 231 (normally about 165-170 TAS in the Flight Levels), was an average cruise of 240+ knots. Peoria to Maryland in under two hours. You do not need a very big fuel tank for that.

I have zero experience with turbocharged aircraft; like I said I'm in the justification phase for a bravo right now. I do have plenty of experience with turbo-props, turbojets and turbofans, though... And I like the speed... But can't afford the entry cost, let alone the operations cost! It's the de-ice capability that's really got me looking around, though. I love my J, the speed and performance has worked very well for me out in the Rockies for the cost, but wintertime has the potential to slow me down (although I have only had to cancel one trip in 4 years due to icing).

Anyway, keep going back and forth on it... Like I said, my typical mission is only 330nm or so... The extra speed over the J of pretty much all piston aircraft in my budget is kind of N/A.. But the operational cost certainly is relevant. Again, the de-ice capability brings something tangable to the table for my mission though.... Two years ago if you'd asked me, I'd be against a single engine recip flying in icing conditions... Now here I am....

[M016576]

Agreed you can make 450 or more in a big hurry if your baffling is bad, the OAT is high, and you make the mistake of all mistakes with a turbo, which is to lean for climb because you read somewhere that is the way to do it. That works for NA engines. Leaning for climb is not a great idea in a turbo. I have talked to pilots who say they can do a cruise climb and keep the temps low while leaning a turbo, but that is a shallow climb at a high airspeed. It is way better to open the cowl flaps and run the engine at 100% where the fuel flow will be boosted by the fuel distribution system, so the temps will stay cool in the engine. I will occasionally do a climb of a couple thousand feet (meaning two thousand or less at a cruise power setting, but not a sustained climb to a high cruising altitude.

If you want to justify a Bravo, think tailwinds aloft. On a typical west to east trip they can be anywhere from 25-75 knots and occasionally you get some real gales. So take the Bravo's TAS, say its 190, and add 75, you are doing low turboprop speeds. The return flight will need to be lower, but that would be true regardless of the engine type. My best flight ever in my lowly 231 (normally about 165-170 TAS in the Flight Levels), was an average cruise of 240+ knots. Peoria to Maryland in under two hours. You do not need a very big fuel tank for that.

I have zero experience with turbocharged aircraft; like I said I'm in the justification phase for a bravo right now. I do have plenty of experience with turbo-props, turbojets and turbofans, though... And I like the speed... But can't afford the entry cost, let alone the operations cost! It's the de-ice capability that's really got me looking around, though. I love my J, the speed and performance has worked very well for me out in the Rockies for the cost, but wintertime has the potential to slow me down (although I have only had to cancel one trip in 4 years due to icing).

Anyway, keep going back and forth on it... Like I said, my typical mission is only 330nm or so... The extra speed over the J of pretty much all piston aircraft in my budget is kind of N/A.. But the operational cost certainly is relevant. Again, the de-ice capability brings something tangable to the table for my mission though.... Two years ago if you'd asked me, I'd be against a single engine recip flying in icing conditions... Now here I am....

[jlunseth]

You might want to look at the Ovation.  It can be purchased with FIKI TKS and I understand it can go quite high.  The NA relative of the Bravo.  You might also take a serious look at the 252, it also can be FIKI TKS, it is faster than the 231, and prices and fuel flow are both lower than the Bravo.  I have loved the 231 for trips into the Rockies, mountain weather is not much of a factor when you can fly above it all, and mountain takeoffs are a non-event.  My aircraft makes 100% HP even at Leadville (and quite a bit higher than that).