180 hp best range power setting

[blueldr]

It seems to me that the ones I've seen pictures of showed a different tail too.

I'll bet it is a world beater on Alaskan gravel bars!

[doug8082a]

It was a real good demonstration of hull speed if that term applies to airplanes as well as boats. Reminded me of a tug boat, it doesn't matter how much horsepower you put in one, it's not going any faster.

An extreme example of the opposite would be the Cassutt Formula 1 racer that can do over 200mph with an O-200. Take a C150/152 with an O-200 and you only go 95mph (give or take a few).

[GAHorn]

Top speed improvement is usually at the sacrifice of low-speed handling and takeoff distances.

Curious to discover how such a speedy aircraft might fare with regard to takeoff distance (when compared to a C-150)... I found the following link about Cassutt Forumula 1 racers.

I was reading the excellent investigation article when it struck me that it's a fine example of why we should not be performing aerobatics in non-aerobatic aircraft, and how pilots, even when qualified/trained in aerobatic manuevers, can still get themselves into unexpected trouble.

Notice the investigation's commentary regarding negative/positive "push-pull phenomenon".

http://www.aaib.gov.uk/cms_resources/df ... 500678.pdf

[hilltop170]

It seems to me that the ones I've seen pictures of showed a different tail too.

I'll bet it is a world beater on Alaskan gravel bars!

Check out this article on the SM 1019 Turbine Birddog, http://www.warbirds-eaa.org/articles/04_02_featue.pdf.

As far as short field performance, the book says for shortest take-off, to power-up the turbine engine with the brakes locked then release when 100% is reached. That might suck a lot of rocks and sand into the prop or engine compressor on a gravel bar. Power changes should be made smoothly on a turbine so if brakes are not held, a lot of room is used up before full power is obtained. I'm told it's not good for the health of the turbine to jam the throttle to full like you would on a piston engine. But once again, let your pocketbook be your guide.

[cessna170bdriver]

By golly, thats's pretty impressive!

Almost seven miles per gallon!

Leave it to the Italians to develop a better Bird Dog.

blueldr-
Not only that, but Jet A averaged $5.32/gal mostly due to the Canadian fuel stops. The 16.7 hour trip cost $1653 just for fuel!

Like a Stearman (13gph to go 80kts) that Italian Birddog sounds like an airplane you fly just because it is what it is. Assuming similar prices for 100LL, even a 310 could have done the trip for around $400 cheaper, and you could have hauled another couple and LOTS of luggage (but obviously with more limitations on where you could land it ). For pure grin factor, I'd take the Birddog.

Miles

[Roesbery]

Lucky,
OK, Will try it one more time. I have a chart ( a bit aged ) of power settings for the Lyc. 0360 A1A. MPxRPM=fuel burn If you want a photo copy send me your address etc. via messages or e-mail and I'll mail it to you. Or anyone else that needs one. Charlie

[Lucky]

Thanks for all the input! Charlie, I just sent you an email...I've been out of town for a few days.

Going with the stock numbers seems to make sense, as drag is still the key factor. I don't have any rpm limitations, so I'll play around and see what settings work best.

[jamyat]

Sorry but I don't believe it!!!

150 at 7.5 gph NO WAY!!!

I have a O-360 Lyc. The airplane is clean and light and the best I can do
is 115 kts at 8 gph. I know the Continental isn't THAT much more effficient than the Lyc.

Buck..........Galena, AK

I am the owner of the Cont IO360 that blueldr referred to. It is easy enough to verify the fuel burn from the gas pump reading and the time on the GPS. I don't mean that once upon a time it made 7.5 gph, I mean that it does it routinely. To get that fuel burn, I make a high power climb at 15 gph to about 3500 feet (my field elevation is 1200). I level for cruise and then do a cruise climb to my cruising altitude. The engine will lean to just a little over 7 gph on the fuel pressure/flow gauge at power setting of about 62%. The Cont is a very efficient engine. It is fuel injected with the air induction system on top of the engine. The induction is cross flow with intake on top of the engine and exhaust on the bottom. The valves are angled to give a very nearly hemi-head combustion chamber. The exhaust manifolds are from the front engine of a Cessna 377 shortened to fit the 170. The left muffler for the cabin heat is from a Bonanza, the right is from a Hawk XP. The tail pipes are from a Bonanza with inside diameter of about 2 and 3/8 inches, but shortened to fit the 170.

It's harder to get the true airspeed since there are so many variables involved. However, the airspeed indicator has been bench calibrated so its error is in the installation. Then of course there is the error in reading it. However, the E6B in the GPS usually gives a true airspeed close to 130 knots. This can be verified from the ground speed and the winds aloft forcast. I routinely see ground speeds of 130 knots and more. So how can this be? Maybe it's the extra horse power. Maybe it's the constant speed prop. Maybe it's the cleanup from eliminating the venturi and the exhaust pipes sticking out of the nose of the cowl. Maybe it's the wheel pants and brake covers. Maybe the fairing of the brake lines. Maybe it's because the airplane is in good rig and flies ball centered with feet on the floor. Maybe it's all these things taken together. I am satisfied that the airplane cruises at or near 130 knots (150 mph). I should also mention that it attains this speed at altitudes between 5000 and 8500 feet.

[c170b53]

So no special magnets?

[buchanan]

Sorry……..call me skeptical but I would still have to see it to believe it. When I tested my C-170B it had the Avcon conversion, a 76” prop with rpm limitations and a stock wing. The airplane weighed about 1325, was polished and had the vacuum generators removed and it was on *8:00 tires. What I did was to fly 115kts on the GPS two ways and then keep that power setting and altitude [6,500”] for the remainder of the flight (usually no longer than one hour), then measure the fuel burned and see what I got. It was NEVER less than 8 ghp. This was tach hours. Now with the Sportsman STOL and 80” prop (no limitations) I fly slower and burn more fuel. But that hole shot is NICE!!
Here is a “formula” I came across that may be applicable.
If you assume 62% power and your airplane is 210hp then your BSFC is about 0.34 If your airplane is 195hp then your BSFC is about 0.367. If it were 180hp then the BSFC would be 0.396. All of which seem optimistic using the scenario below. This scenario is full power so maybe an engine is MUCH less efficient at 62% power.
Thoughts Tim???
Buck Buchanan, Galena, AK

"formula"
A more commonly used yardstick for expressing thermal efficiency is known as Brake Specific Fuel Consumption (BSFC). It is simply fuel flow (in pounds-per-hour) divided by measured HP, and is expressed in Pounds-per-Hour-per-HP.
BSFC = Fuel Flow (PPH) ÷ Horsepower
or BSFC = 5.92 x Fuel Flow (GPH) ÷ Horsepower

This tool is also an important yardstick for comparing the performance of one engine to another and for evaluating the reasonableness of performance claims.
An excellent BSFC for a well-developed, naturally-aspirated, high-performance liquid-cooled engine at 100% power is in the neighborhood of 0.44 – 0.45. Claims of gasoline engine BSFC values less than 0.42 at max power tend to be suspect. At reduced power settings (in the region of 70% and below) BSFC values of 0.38 have been achieved, but they are not commonplace.
The operator manual for a 300 HP Lycoming IO-540-K, L, or M series engine shows a full power fuel flow of 24 GPH which is a BSFC of 0.474 ( 24 * 5.92 ÷ 300 ) and a TE of 28.3% (explained above). Those numbers aren't too bad for an air cooled engine which meets the FAR-required detonation margins. However, the turbocharged TIO-540-V2AD requires a MINIMUM of 39.2 GPH at 350 HP for a BSFC of 0.663 and a TE of 20.4%.
So if someone tells you that they have a piston engine which, at max power, makes 300 HP on 20 GPH of gasoline, you quickly calculate a BSFC of 0.39 and a Thermal Efficiency of 34.4%. You should be highly suspicious of such a claim.

[jamyat]

As I said before, computing gph is quite easy. You only need the number from the pump and the time. I use the GPS time, not tach. It consistently does 7.5 gph and not just once in a blue moon. As I said before, there is a technique. Use full power for takeoff. At about 50 feet altitude, turn prop back to 2600. Fuel flow/pressure gauge indicates 15 gph at this power setting. Climb about 2000 feet. Level and set up for cruise at most 65%. Engine will lean to just slightly over 7 gph according to fuel flow/pressure gauge. Roll the trim for a slow climb 300-400 fpm to cruise altitude, then level cruise.

A couple of things I forgot in my first post. Not only is this engine fuel injected, but the induction system located on top of the engine is tuned. We removed the cooling lip from the bottom of the cowl and installed a fairing that covers about 2/3 of the cooling air exhaust. I don't have any way to measure it, but it seems reasonable that cooling drag was decreased. The engine cools quite well with this mod.

Just for emphasis, I am not using the fuel flow/pressure gauge to compute gph. I am only using gallons from the pump and time from the Garmin GPS. GPS time starts when the aircraft speed exceeds 30 kts and 500 feet altitude is gained. It stops when you land and speed drops below 30 kts.

[Chris Christensen]

I have the same problem of not having any viable cruise numbers.
I am currently getting one of the JPI 800 series engine analyzers installed with fuel flow etc. Hope to be able to get some cruise #s this spring and fall while flying from Ried Hilview in San Jose Ca. to McCall Idaho.

Should have enough time to get the numbers at several altitudes plus the 500. Will advise later on IF:, 1, I can learn how to use the thing. Old dogs - new tricks, etc. 2, I really do get the time off to do so.

I sorta scared myself last summer. The arithmetic in McCall came out to ONLY 8.4 gal per hr.

Set a record of 4 hours and 12 min. Started out at 7,500 till reached just west of the Lake Tahoe area, then went to 9,500 till out over Black Rock Desert, then to 11-500 to clear a lot of dust storms. Check my density alt. on a new lectric inst. and it was near 14,000 so went on oxygen. Got a great tail wind of some 40+ knots. Best GPS ground speed of 172 MPH.

Still not ready to count on that 8.4 GPH.