Tiger folks: service ceiling question

[dukeblue219]

I know there are plenty here with extensive Tiger experience. I am newish to the club and haven't taken mine above 9,500 yet, and while it was still climbing (solo, ~40gal remaining) it wasn't exactly screaming for the sky either. I recall something like 200fpm though I didn't record it. For those who have more Tiger experience than I, what kind of practical ceiling can I expect? Obviously DA comes into play, but on a standard day, are you comfortable planning for 11,500? 12,500?

I'm not talking about flight planning over a 12,490' peak in the Rockies or trying to climb above ice, but just general purpose cruising. The POH for my plane only lists climb performance at max gross and only goes up to 10,000', but I haven't yet explored the limits and am curious to hear experiences of other Tiger owners who have regularly gone above 10k and how the plane performed. Thanks!

 

[poadeleted20]

No way to answer this question without knowing far more about your particular Tiger, its maintenance history, engine condition, modifications, and prop type/pitch. There are far too many possible differences between your Tiger and mine (or anyone else's) to expect your plane to perform like mine.

 

[dukeblue219]

Fair enough. It's something I will try to explore for myself eventually, but rarely do I go above 6-8k anyway. For what it's worth, it's a stock '03 AG-5B with 1500 hours since new and good compressions that's been hangared most of its life in a partnership. I know you have an older model that's probably a bit lighter than mine -- do you ever take it up high? Would you ever do 12,500 or is it too long to get up there?

 

[PilotAlan]

Anthony here had a Tiger in Colorado, where density altitude at the runup pad is regularly over 9000ft DA.

 

[poadeleted21]

Not that this adds anything to the conversation. But I used to routinely take my 1963 PA28-150B (150HP) up to 12,500 to clear the cumulogranite in the Montana Rockies. I'd be highly surprised if a Tiger wouldn't make it up there. It took a while, but it got there.

 

[Clark1961]

Anthony here had a Tiger in Colorado, where density altitude at the runup pad is regularly over 9000ft DA.

Didn't he taxi full length for departure at FTG? (grinning, ducking, running very quickly...okay, as quickly as I can which is sort of ambling along)

 

[ChitDisturber]

I know there are plenty here with extensive Tiger experience. I am newish to the club and haven't taken mine above 9,500 yet, and while it was still climbing (solo, ~40gal remaining) it wasn't exactly screaming for the sky either. I recall something like 200fpm though I didn't record it. For those who have more Tiger experience than I, what kind of practical ceiling can I expect? Obviously DA comes into play, but on a standard day, are you comfortable planning for 11,500? 12,500?

I'm not talking about flight planning over a 12,490' peak in the Rockies or trying to climb above ice, but just general purpose cruising. The POH for my plane only lists climb performance at max gross and only goes up to 10,000', but I haven't yet explored the limits and am curious to hear experiences of other Tiger owners who have regularly gone above 10k and how the plane performed. Thanks!

I think there is a book with all that information in it, if you look in your plane you might find it :wink2:

Second option, go take her up and find out.

 

[dukeblue219]

I think there is a book with all that information in it, if you look in your plane you might find it :wink2:

As I said in the post you quoted.... the POH only lists climb performance up to 10,000ft (80fpm). That seems quite low to me, but the table is only provided at max gross, so I don't have any other reference available.

Second option, go take her up and find out.

Agreed. Just wondering about the experiences of others with similar planes, though.

 

[Baron2PG]

I had my Tiger with a pretty new engine up to ~13K once; wanted to see how high I could go. Probably could have nursed it higher but I grew tired and bored. It was pretty anemic at best. Also, I had an engine monitor which helped me keep the mixture optimized near peak EGT. At those altitudes you're not making much power so the mixture can be set for max heat.

I certainly would not put myself in a situation where I was looking at a piece of granite wanting to climb over it. A little higher OAT or a mountain down draft and you would be history.

I wouldn't flight plan on much of anything above 10K. In reality, unless you have a portion of a route with a high MEA I wouldn't fly the Tiger much above 8K. A little trial and error and you'll find the perfect cruise altitude. You can cut to the chase if the POH provides performance tables.

 

[Clark1961]

I had my Tiger with a pretty new engine up to ~13K once; wanted to see how high I could go. Probably could have nursed it higher but I grew tired and bored. It was pretty anemic at best. Also, I had an engine monitor which helped me keep the mixture optimized near peak EGT. At those altitudes you're not making much power so the mixture can be set for max heat.

I think that the engine manufacturers agree with you that the engine can't be hurt with the mixture knob when the engine isn't making even 3/4 power. That said, we were taught to operate rich, about 100 to 125 degrees, of peak egt for max power. I don't know how much difference it makes from a practical point of view, just sharing how we're taught to operate at high DA.

The AFM for the 'kota is sorta funny because it has best power and best economy settings based on desired engine output, e.g. 75% power. Every time I look at it I have to ask myself what-in-the-heck-do-they-mean by best power and best economy for 75% power? Does one 75% power setting have more power than another 75% power setting?

I can see that there may be more efficient ways to get 75% power but 75% is 75% so there really can't be a "best power." There can be a rich power and a lean power 75% and maybe that's what they really mean...

 

[Baron2PG]

I think that the engine manufacturers agree with you that the engine can't be hurt with the mixture knob when the engine isn't making even 3/4 power. That said, we were taught to operate rich, about 100 to 125 degrees, of peak egt for max power. I don't know how much difference it makes from a practical point of view, just sharing how we're taught to operate at high DA.

The AFM for the 'kota is sorta funny because it has best power and best economy settings based on desired engine output, e.g. 75% power. Every time I look at it I have to ask myself what-in-the-heck-do-they-mean by best power and best economy for 75% power? Does one 75% power setting have more power than another 75% power setting?

I can see that there may be more efficient ways to get 75% power but 75% is 75% so there really can't be a "best power." There can be a rich power and a lean power 75% and maybe that's what they really mean...

At 12K feet the NA engine probably isn't making 50% power. The 75% power at WOT intersection is probably closer to 6K-7K. Been awhile since I flew fixed pitch prop so that probably screws with the power output as well. The mixture is also pretty crude with a carburetor vs. GAMI tuned fuel-injection so the mixture is more of a rough order of magnitude adjustment as the cylinder to cylinder spread is going to be large.

 

[Clark1961]

At 12K feet the NA engine probably isn't making 50% power. The 75% power at WOT intersection is probably closer to 6K-7K. Been awhile since I flew fixed pitch prop so that probably screws with the power output as well. The mixture is also pretty crude with a carburetor vs. GAMI tuned fuel-injection so the mixture is more of a rough order of magnitude adjustment as the cylinder to cylinder spread is going to be large.

Carb'd or injected, go at least 100 degrees rich of peak for best power.

 

[SteveR]

I took a 160hp Traveler to over 18,500 true once (under 18,000 indicated, but over 18,500 or so true per the GPS). I was solo, so more than 300lbs under gross at takeoff, and it was a three hour leg. The elevator was at a ridiculous trim angle to maintain the AOA necessary for level flight. The last few thousand feet were 100 to 200fpm at a time. I believe I went to 12K or so, leveled for 45 minutes or so to burn fuel, then started climbing again.

As for a practical service ceiling, I think 12,500 was reasonable, loaded maybe 200lbs under gross on an average day. Hot days required leveling for a while to cool down. On hot days at gross, above 10,000 wasn't too practical...climb time was 45+ minutes.

 

[Pilawt]

I think there is a book with all that information in it, if you look in your plane you might find it :wink2:

If they were sold at Barnes & Noble, a lot of those books would be on the shelf in the "Fairy Tales" section.

Second option, go take her up and find out.

For something like climb, that's the better option. As the fleet ages, there are a lot of variables that make "book" performance numbers less relevant.

 

[poadeleted20]

Fair enough. It's something I will try to explore for myself eventually, but rarely do I go above 6-8k anyway. For what it's worth, it's a stock '03 AG-5B with 1500 hours since new and good compressions that's been hangared most of its life in a partnership. I know you have an older model that's probably a bit lighter than mine -- do you ever take it up high? Would you ever do 12,500 or is it too long to get up there?

First, the AG-5B's send less power to the prop because of differences in the induction and exhaust systems, so they generally climb and cruise more slowly than otherwise-comparable AA-5B's. Second, good compressions alone don't guarantee the engine is putting out full power -- you need a good static RPM check with a strobe tach to determine that (and note that the proper RPM range varies with the prop pitch). Also, the AG-5B's came with three different possible prop pitches of 61, 63, and 65 pitch, and what you get with those is radically different between the three, and even the 63-pitch Sensenich that was stock with the AG's is also significantly different from the shorter stock AA-series McCauley prop of the same pitch. And, as you note, with the same load, the heavier AG's are probably running a gross weight about 75 lb heavier than the same load in the lighter AA's.

As for what I do with mine, I'm up in the 12-13000 range rather often in the summer to get to cool, dry, smooth air. But while I have the same 63-pitch Sensenich prop with which most AG's left the factory, I also have the LoPresti induction system and Lycon ported and flow-matched cylinders which put out significantly more power than a stock engine, and I'm usually carrying less than 400 lb payload and my empty weight of about 1465 is probably 75 lb less than your AG's. Climb from 10,000 up is only around 250 ft/min, but usually nobody's bothered by a slow climb in that range.

Does that help?

 

[poadeleted20]

I had my Tiger with a pretty new engine up to ~13K once; wanted to see how high I could go. Probably could have nursed it higher but I grew tired and bored. It was pretty anemic at best. Also, I had an engine monitor which helped me keep the mixture optimized near peak EGT. At those altitudes you're not making much power so the mixture can be set for max heat.

The "max heat" for which you should be leaning for best power up there is near peak CHT, not EGT, but even that isn't what you should be targeting. With the fixed pitch prop you find on all but a dozen or so Tigers, you should be leaning to max RPM, not any particular temperature, and you don't need an engine monitor to do that.

 

[dukeblue219]

Does that help?

Yes. I didn't know about the possible power difference between AAs and AGs for one thing, and I should go look up the pitch of the prop just out of curiosity. Granted, the Grumman board would be a better place to ask I suppose. Thanks Ron.

 

[danhagan]

Same as Ron. On long XC I am usually at 11.5 or 10.5. I've been to the service ceiling 13,400 once and was only getting 100-150 FPM climb at that point - could've gone higher, but it was pretty anemic (was solo but full fuel).

 

[Art VanDelay]

About the only thing I didn't like about my Tiger was the fuel burn. That airplane would have been ideal if only it had come with a constant speed prop.

 

[danhagan]

About the only thing I didn't like about my Tiger was the fuel burn. That airplane would have been ideal if only it had come with a constant speed prop.

C/S would be nice. I normally burn 8.8 GPH at 9500, am near but am not at redline (usually 2500 RPM). If putzing around, I usually meander at 2200 RPM at 7 GPH.

 

[FastEddieB]

I figured 132k @ 10 gph in my AA5B Tiger at middle altitudes.

I think I had her up to 14k once to top some clouds. Very anemic climb with two on board.

 

[kyleb]

C/S would be nice. I normally burn 8.8 GPH at 9500, am near but am not at redline (usually 2500 RPM). If putzing around, I usually meander at 2200 RPM at 7 GPH.

What was your TAS at 8.8 GPH and 9500'?

 

[poadeleted20]

About the only thing I didn't like about my Tiger was the fuel burn. That airplane would have been ideal if only it had come with a constant speed prop.

I've flown Tigers with them. Doesn't change the fuel burn at any given speed significantly since the engine's HP/lb/hr is pretty much a constant. All it lets you do is generate more power without overspeeding but you burn more fuel when you do that.

 

[Van Johnston]

Took me 27 min to climb from 1,000 to 11,500 on a hot morning in Oklahoma last June. Solo, 76 Tiger, McCauley prop.

 

[Art VanDelay]

C/S would be nice. I normally burn 8.8 GPH at 9500, am near but am not at redline (usually 2500 RPM). If putzing around, I usually meander at 2200 RPM at 7 GPH.

I never saw anything close to that. Do you have an actual Fuel Flow gauge or are you just estimating ?

 

[Doggtyred]

ABout 12 years ago, when I went from Houston to Dayton to visit my then Bro in law, I took our club's Tiger up and back. On the return trip, it was right after a strong cold front (bad enough that I was worried about surface winds while tied down)…. My choices were fly low, take 25 its on the nose and get beat up for the first couple hundred miles, or climb up to 10000-11000 feet and take 50 knots on the nose… I took the headwind and made an extra fuel stop. I don't remember anything bad about performance, but I do remember it as being the highest I'd been in the Tiger. That was one soul, full tank, and light baggage.

I could have kept climbing, but I didn't have oxygen and I'd already had a few flights at 11-12000 in a Bo that were hours long and I didn't like the way I felt when they were finished…

For the power, you can't go wrong with a Tiger if its got a good engine. A power flow can only help. Just wish they had a CS prop.

 

[danhagan]

What was your TAS at 8.8 GPH and 9500'?

Usually near 125 knots...to solidly hit 130-133 then I'm at 9.5-10 WOT in cruise. In my area (desert) climbs are long and hot, so I normally take off leaned for field elevation and increase fuel flow in the climb to keep things cooled off. On hottest days it can sometimes goto 13.5 GPH for a 10-15 minute climb to cool air. In calm (no wind) cruise I can't reach the 139 kt book numbers despite being re-rigged at FletchAIR.

I never saw anything close to that. Do you have an actual Fuel Flow gauge or are you just estimating ?

Yes I have a fuel flow gauge, but those numbers are after establishing in cruise and readjusting mix. Am usually within a half gallon of what it is indicating when refueling as well. Have also noticed if you lean to stumble in cruise and enrichen as you normally would, the fuel analyzer will usually demonstrate a slight improvement over what you previously had set.

Also, there is about an 1/8" of throttle travel that appears to not effect speed (just prior to WOT) but does effect fuel burn. That's why I am usually at 2450 to 2500 and not WOT on long XC. Have done a LOT of El Paso to Fullerton California trips, so have had plenty of time to experiment in cruise.

 

[poadeleted20]

One word of caution on the various RPM values thrown around here -- or rather, two words:

1. The mechanical tachs in older AA-series Grummans are susceptible to long-term wear resulting in reading significantly lower-than-actual RPM. I've seen 100-150 low routinely, and as much as 200-250 in rare cases. With such a tach, you may think you're only turning 2550 RPM when you're actually pushing the 2700 RPM redline. If you have a smart phone, there are a number of apps available to help check this without investing in a strobe tach.
2. With fixed pitch props and normally aspirated engines, the RPM for a given %HP varies with altitude -- takes more RPM at higher altitude to get the same HP. For the engine/prop combinations we're discussing, that's about 100 RPM for each 5000 feet of altitude. So, if 2500 is 75% at SL, it takes about 2650 RPM to pull 75% at 7,500, and 2500 at that higher altitude may only be about 62% power. See your power charts for details, and remember that there are no reliable power charts for AA-5B's with the STC'd Sensenich prop -- you have to build them yourself with a manifold pressure gauge and an accurate tach.

 

[bkspero]

Sorry to be so late to the party. When ferrying my newly purchased '76 Tiger to the east coast from California in January of 2012, the ferry pilot who was flying with me over the Rockies took it north of Jackson Hole to see the Grand Tetons. Plane has a 63 pitch Sensenich prop and the engine had 400 hrs on a factory overhaul at the time. We were loaded to within about 25 lbs of max gross at take-off, and had probably burned about 90 lbs of fuel at that point. The OAT gauge did not read correctly (it was showing +1 deg C at altitude), and I do not recall the altimeter setting (although it was in the middle of a high pressure system, so almost certainly above 30 inches Hg. No wind.

We crossed just south of the 14000 ft peaks at about 12,800 ft and the plane was still able to climb pretty well. I hesitate to quote a number because it would be from my too frequently faulty memory, but I recall getting about 250 ft/min in the last portions of the climb.

 

[Martymccasland]

I had a 79 Tiger with ported&polished cylinders, LoPresti induction, etc. Highest I ever had the plane was 18,400... ATC gave me a local clearance when I got close to the Class A. 14k to 18k took quite a while -- and it was cold. At 18,400, there was no tricks left to do to get the plane to climb even another 50 feet. That was it.

Remember at one point my groundspeed into the stiff winter wind was 17 knots. ATC turned us the opposite direction for the descent back to the airport. We hit 227 knots coming back -- which remained, in that one flight, the fastest and slowest speeds I ever saw in my Tiger over the years of ownership.

For practical flying with PAXs, luggage, flying near gross, I would think really hard going above 10-11k just because the climb performance fell off so much past about 9-10k.

As other's have stated, there's no real standard Tiger performance like many may find with something like a 172. Lots of variables. Some will cruise 145 knots at 2700 rpm, some will barely get 130-132 knots. Lots of airframe drag issues, ill-fitting plastic, little mods, prop, etc... Ditto for climb and ceiling performance. It's basically a very slick airframe that achieves it's relatively high speed. The degree to which owners have kept it slick, or made it slicker (counter-sinking the few rivets on the bottom, tightening up joints, wheel pants, etc.) make a significant difference. I sped my Tiger up 8 knots after buying by doing such clean-ups....

 

[flyingron]

Can't vouch for Tigers but when we were in Colorado we had no problem (on a not too hot day) getting the Cheetah up above 12,5 (and even to 14) to clear some of the passes.