The earlier posts regarding power settings, fuel burn, and airspeed for 170s was very informative.
I have a 180 HP Lycoming and would be interested in the power settings people are using with their 180 HP Lycoming powered 170s, along with fuel consumption and speed. I suspect that the bigger engine provides better takeoff performance, both on distance and loads (although officially there is no gross increase), and some speed. But perhaps the speed increase is not that much ? ? ?
I haven't flown straight wheels in a while. I've been flying FliLite 3000 Hydraulic Wheel Skis and floats. With average to heavy loads (hypothetically -- full wing tanks and 400-900 pounds inside), I've been noticing the following:
1) 105 mph at 24.0 Manifold Pressure and 2400 RPM
2) Burning between about 8.5 gal/hr
I've noticed that the plane flies at about the same speed with either wheel skis or floats.
What power settings do you guys use and how do my numbers compare?
-Rob Stone
N2814C
Airspeed and Power Settings for Lycoming Powered 170s
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Fuel burn calculations
Rob, I purchased N170GA last January and was concerned about fuel burn because it was a new aircraft for me. I have a C/S prop, so my speeds might be different than those with a fixed prop. I've been keeping records on tach times, fuel burns, etc. Here's what I have been able determine:
2450 x 2450 11-11.5 GPH
2400 x 2400 10 GPH
2350 x 2350 9.5 GPH
These seem to hold up pretty well, but I have had one instance where I was way off for some unknown reason (12.2 GPH). It occurred on a long trip with a headwind so you might guess what happened. When I stopped for gas (unplanned stop 30 miles short of destination because I was feeling uneasy) I was astonished when the fuel slip read 37 gals! That experience taught me 2 things. Don't compromise on "reserves", and be meticulous with record keeping. The only thing I can figure was perhaps I wasn't careful about setting the MP and Prop and was running stronger than I thought. Looking at the progression in my numbers above, it would only take being high by 100 x 100 to get the fuel burn up over 12 GPH.
I only find that I loose 3-4 knots between each of the settings above, but the fuel savings is substantial.
I'd be interested to hear others findings too.
Neil
N170GA
2450 x 2450 11-11.5 GPH
2400 x 2400 10 GPH
2350 x 2350 9.5 GPH
These seem to hold up pretty well, but I have had one instance where I was way off for some unknown reason (12.2 GPH). It occurred on a long trip with a headwind so you might guess what happened. When I stopped for gas (unplanned stop 30 miles short of destination because I was feeling uneasy) I was astonished when the fuel slip read 37 gals! That experience taught me 2 things. Don't compromise on "reserves", and be meticulous with record keeping. The only thing I can figure was perhaps I wasn't careful about setting the MP and Prop and was running stronger than I thought. Looking at the progression in my numbers above, it would only take being high by 100 x 100 to get the fuel burn up over 12 GPH.
I only find that I loose 3-4 knots between each of the settings above, but the fuel savings is substantial.
I'd be interested to hear others findings too.
Neil
N170GA
My bird is a bit unusual in that I have not only the 0-360, but also a Lazar ignition and the Power Flow System tuned exhaust. I've found 2450 square gives about 140 mph (8:00 tires) and burns about 10.5 gph. However, for me, getting there is most of the fun. So, 2300 rpm and 18" mp ;gives 112-116 mph and 6.5 gph. Take off and climb can only be experienced to be belived. This is all with the bird very light.
Pete
Pete
Pete Kuckenberg
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Eric, the Lazar ingition was installed at Lebanon, Oregon, but that FBO is no longer in business. It does have an STC and took about two hours to install and set up. I never checked the numbers all that close, but I did get significant savings in fuel consumption (about 2 gph as I recall) and enough more power to be definatly noticeable. Not as much as the tuned exhaust, but enough to produce a big grin! It will also start up and idle at about the same rpm as that produced by the starter. I haven't heard much about them lately, but I'm glad I've got mine! Pete
Pete Kuckenberg
Pete, Eric, Neil, and Charlie, thank you for your replies.
Neil:
Like you, Neil, my plane also has the constant speed prop. I am running the 80 inch blades, however. I put the longer blade on at the same time as a major overhaul and other mods, so I'm not certain the impact the longer blades have had on airspeed and fuel consumption. The take off performance and slow flight have been inhanced, but the Sportsman stol kit contributes to these as well. And the Sportsman stol kit probably makes the plane fly a little slower than if there was no stol kit. Your power settings to fuel flow chart is excellent -- thanks! How fast do you fly at the settings you displayed for us?
Charlie:
You make a good point about the tach and Man. Press. Gauge. Right after the major overhaul, I purchased a digital RPM and a Man. Press. Gauge. I had the prop balanced and so the RPM does read correctly. I have had numerous problems with the Man. Press. Gauge (and we're still working on that problem -- it's been ongoing for more than a year). The avionics shop tells me that it works fine in the shop, but the Man. Press. climbs through the roof -- sometimes reading upwards of 40-50 inches of pressure after 1/2 hour into the flight. And these readings are sporatic. My take off performance is outstanding, but the in flight performance has been troubling -- thus the reason for my post regarding speeds, power settings, and fuel burn. Thanks for the input. Your chart will certainly help out with my concerns.
Pete,
Sounds like the tuned exhaust and Lazar ignition are great mods! A year or two ago I remember discussing the tuned exhaust with someone and reading about it on line. It sounded like a good mod, at a cost of about $1,500 or so. My memory is not so good regarding the cost.
Where would one find information about the Tuned Exhaust and Lazar ignition modifications? Since I'm in Anchorage, I would prefer to buy the materials and have my mechanic at Lake Hood perform the installation.
Thanks again,
Rob Stone
N2814C
-Rob
Neil:
Like you, Neil, my plane also has the constant speed prop. I am running the 80 inch blades, however. I put the longer blade on at the same time as a major overhaul and other mods, so I'm not certain the impact the longer blades have had on airspeed and fuel consumption. The take off performance and slow flight have been inhanced, but the Sportsman stol kit contributes to these as well. And the Sportsman stol kit probably makes the plane fly a little slower than if there was no stol kit. Your power settings to fuel flow chart is excellent -- thanks! How fast do you fly at the settings you displayed for us?
Charlie:
You make a good point about the tach and Man. Press. Gauge. Right after the major overhaul, I purchased a digital RPM and a Man. Press. Gauge. I had the prop balanced and so the RPM does read correctly. I have had numerous problems with the Man. Press. Gauge (and we're still working on that problem -- it's been ongoing for more than a year). The avionics shop tells me that it works fine in the shop, but the Man. Press. climbs through the roof -- sometimes reading upwards of 40-50 inches of pressure after 1/2 hour into the flight. And these readings are sporatic. My take off performance is outstanding, but the in flight performance has been troubling -- thus the reason for my post regarding speeds, power settings, and fuel burn. Thanks for the input. Your chart will certainly help out with my concerns.
Pete,
Sounds like the tuned exhaust and Lazar ignition are great mods! A year or two ago I remember discussing the tuned exhaust with someone and reading about it on line. It sounded like a good mod, at a cost of about $1,500 or so. My memory is not so good regarding the cost.
Where would one find information about the Tuned Exhaust and Lazar ignition modifications? Since I'm in Anchorage, I would prefer to buy the materials and have my mechanic at Lake Hood perform the installation.
Thanks again,
Rob Stone
N2814C
-Rob
Pete,
Believe me, I've thought of that! My old days as a semi shade tree mechanic gives me thoughts of four barrel carbs, headers, and hi rise manifolds, but my sense is that getting an STC for them would be impossible.
The ignition/exhaust route would be much easier. I have a muffler that is showing signs of old age now, and I was thinking of fixing it during my next annual. Maybe now's the time for a tuned exhaust?
Believe me, I've thought of that! My old days as a semi shade tree mechanic gives me thoughts of four barrel carbs, headers, and hi rise manifolds, but my sense is that getting an STC for them would be impossible.
The ignition/exhaust route would be much easier. I have a muffler that is showing signs of old age now, and I was thinking of fixing it during my next annual. Maybe now's the time for a tuned exhaust?Thought I could lay my hands on that chart but have been unable to find it. I gave a copy to a friend a few years ago but will have to wait a couple weeks till he is back in town to get a copy of his chart. But will post it when I get it. I like to keep a copy in the plane, so if I need to stretch the fuel I can look up the right power settings to do so. Charlie
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Classic170
- Posts: 10
- Joined: Mon Apr 22, 2002 6:31 pm
STC for Powerflow
Pete I looked on the web site for Power flow and they do not seem to have a STC for the 170. Did you go the 337 route? Do you have a copy of the 337? Thanks Tom
Tom, Yes, I did go the 337 route. The FAA here in Spokane (closest outlet, but operates under the Seattle office) wouldn't even consider the mod So I took it to Denver, had the work done and got it approved. It could also have been done in Alaska.
However, Power Flow has (As I understand it) decided not to sell the system for any airframe for which they have no STC. Apparently they had several people install them on Non STC'd planes and they found they had to do a lot of cutting, fitting and modifying. (It took about 40 hours shop time to make mine work, but I expected it and was happy with the whole operation) Anyway, there was enough whining and sniveling that Power Flow took this route. Tom my knowledge there are only four 170s with the mod. Pete
However, Power Flow has (As I understand it) decided not to sell the system for any airframe for which they have no STC. Apparently they had several people install them on Non STC'd planes and they found they had to do a lot of cutting, fitting and modifying. (It took about 40 hours shop time to make mine work, but I expected it and was happy with the whole operation) Anyway, there was enough whining and sniveling that Power Flow took this route. Tom my knowledge there are only four 170s with the mod. Pete
Pete Kuckenberg
Using a True Tach, I found out that my tach is accurate. The Man. Press. Gauge is still causing problems.
I'm turning 2660 on takeoff with the constant speed prop with the 80" blades. Any comments regarding whether the governor should be adjusted to obtain 2700 RPM?
I'll test my speed at various Man. Pressure and RPM settings on Sunday and post my airspeed on Monday. It would be interesting to compare speeds with the 80" blades, compared with the 76" blades.
I'm turning 2660 on takeoff with the constant speed prop with the 80" blades. Any comments regarding whether the governor should be adjusted to obtain 2700 RPM?
I'll test my speed at various Man. Pressure and RPM settings on Sunday and post my airspeed on Monday. It would be interesting to compare speeds with the 80" blades, compared with the 76" blades.
Bolt on Horsepower!
[quote="N2580D"]Rather than make claims myself about the tuned exhaust systems, I'd suggest you ask any competent race car mechanic, or just look yourself at any modern race car. You won't find one without a tuned exhaust. Same principles apply to ANY internal combustion engine. Pete[/quote]
I am not going to question anyones experience with their engine conversion performance, their exhaust modification performance or the advantages or disadvantages of the additional modifications to a plane that used technology that was already 25 years old when the 170 was just off the drawing board.
What I will question is "Snake Oil" hype from after market manufacturers without much actual "truth in advertising" mixed in. No doubt an electronic ignition / fuel metering (read : fuel injection) system coupled with a lot of computer controlled sensors and probes would probably benefit the fuel consumption / performance of any 1930's technology. "But" is it cost effective? Probably not.
Tuned exhausts are usually not meant to add any more horespower than the engine produces on it's own. If an exhaust muffler is placed on an engine after the manufacturer builds the engine, and makes a statement as to the HP generated by his engine, then naturally there will be less power available after that installation. That loss is not necessarily reported but the advertised HP for the product using the power plant is telling you what you can reasonably expect out of the HP that is available. Tuned exhaust may lessen the loss but will develop very little in excess of the original HP. Most racing applications are meant to burn more fuel not less, and at the expense of longevity. ie: a dragster engine may be torn down and vital components replaced between races! "any engine" covers a lot of ground and generalities usually have errors! {;>.
I have some doubt that users can reliably expect fuel consumption to be less on a 360" engine over a 300" using much the same technology for fuel metering. The old POH (Continental power) I have gives some ridiculous number of 5.5gph fuel burn at 12500' and 2300rpm! (It takes 12 gallons to get to 12500'!) And I never was able to maintain 5000' altitude at 2100rpm at gross weight to achieve 5.2gph much less get anywhere! There is a little disclaimer at the bottom of the chart stating "......(ie:don't believe any of this!) ..may be subject to carb.....etc. etc.
My two cents worth!
I am not going to question anyones experience with their engine conversion performance, their exhaust modification performance or the advantages or disadvantages of the additional modifications to a plane that used technology that was already 25 years old when the 170 was just off the drawing board.
What I will question is "Snake Oil" hype from after market manufacturers without much actual "truth in advertising" mixed in. No doubt an electronic ignition / fuel metering (read : fuel injection) system coupled with a lot of computer controlled sensors and probes would probably benefit the fuel consumption / performance of any 1930's technology. "But" is it cost effective? Probably not.
Tuned exhausts are usually not meant to add any more horespower than the engine produces on it's own. If an exhaust muffler is placed on an engine after the manufacturer builds the engine, and makes a statement as to the HP generated by his engine, then naturally there will be less power available after that installation. That loss is not necessarily reported but the advertised HP for the product using the power plant is telling you what you can reasonably expect out of the HP that is available. Tuned exhaust may lessen the loss but will develop very little in excess of the original HP. Most racing applications are meant to burn more fuel not less, and at the expense of longevity. ie: a dragster engine may be torn down and vital components replaced between races! "any engine" covers a lot of ground and generalities usually have errors! {;>.
I have some doubt that users can reliably expect fuel consumption to be less on a 360" engine over a 300" using much the same technology for fuel metering. The old POH (Continental power) I have gives some ridiculous number of 5.5gph fuel burn at 12500' and 2300rpm! (It takes 12 gallons to get to 12500'!) And I never was able to maintain 5000' altitude at 2100rpm at gross weight to achieve 5.2gph much less get anywhere! There is a little disclaimer at the bottom of the chart stating "......(ie:don't believe any of this!) ..may be subject to carb.....etc. etc.
My two cents worth!