maule mxt-7-180 real world performance?

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Joe-FBS
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Post by Joe-FBS »

About six months ago, I bought a quarter of a 1998 MXT-7-180. I have only 25 hours on it so far so still with a lot to learn. I reckon that it gives:

- At 24 inches and 2400 rpm about 115 knots (132 mph) and about 38 litres an hour (about 10 USG)

- At 23 inches and 2300 rpm about 105 (120 mph) knots and about 34 litres an hour (about 9 USG)

- Two-up and half tanks on an English summer day (so 15-20 Celsius i.e. about 65 F), it uses about half of our 500 metre long sea-level (as near as makes no difference) strip (flat, smooth, short grass) to take-off and land (so about 800 feet).

All of which seem to be somewhere near what others have already said.

I love it to bits but I have wanted a Maule since I first saw one as a teenager about forty years ago.

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andy
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Post by andy »

Sounds about right as long as you don't have big tundra tires. They add a lot of drag and take 5 - 10 knots off your cruise speed.
Andy
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stevesMaule180
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Performance

Post by stevesMaule180 »

Mountain Doctor wrote:Hangared and cared for the fabric will last as long as you do.

The problem is holes punched in the bottom when operating off airport and/or on gravel.

I have had to deal with several myself. I now use only pavement and grass most of the time.

As far as performance my FP 180 cruises 75% in standard conditions about 135 MPH. It is on the slow side of the adequate spectrum but works.

The CS should be 10 MPH faster ........

Is FP 180 a Maule?
.... We have ‘07 Mxt-7-180 With C/S PROP, but get ‘only’ 121 mph/ 105 knots.
Passing the faster planes, as they re-fuel ðŸ˜￾

Mountain Doctor
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Post by Mountain Doctor »

MXT-7 180A

2002 Maule Comet

Fixed pitch Trigear O-360 Lycoming
I am an AME in Richland, Washington. Please call for an appointment!

560 Gage Blvd.
Richland, WA 99352
(509) 628-2843

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chris_01
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Post by chris_01 »

Mountain Doctor wrote:
135 MPH/ 117 knots is the Maule number they gave me when I bought the plane and represents the best case scenario.

7,500' DA WOT is about 75% max power. Works out to about 2,700 RPM so redline. Maybe a little less.

In real life I see 110 knots. Depending on the wind and altitude and a dozen other factors I route plan 110 and it's about right.

The plane is all stock and in no universe do I consider it fast, but I also drive a Bonanza.

It's fine to run at 2,700 RPM all day as long as you are not continuous above about 75% power.
Thanks for the hint with the 7500' DA WOT mapping around 75% power. That's good to know because having the FP prop and an EDM 830, it is quite tricky to set the correct adjustments for the power percentage parameter that is shown.
Following the book, it gives me an RPM/FF ratio which is supposed to be 75%. When setting this, it still doesn't feel right.
Also the book tells me under Power Plan Limits "180hp@2700rpm, full throttle continuous" I understand that WOT is OK at any time up to and below 2700 RPM. Knowing that other a/c have a max continuous RPM of 2500, it feels bad to run it at 2700 continuously - or is this yet another difference between FP and VP props?

Does anyone have some numbers that may be lmiting on MAP? I have the number on the EDM and hence I could use it to decide whether I'm over or below 75%. Currently, when I fly with the usual 2400rpm, the MAP is usually below 24 whereas with the VP prop, I'd set both to 2400/24 and would be happily cruising around without thinking much...

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andy
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Post by andy »

The higher the RPM the more wear on the crankshaft and other engine parts. While the engine might operate more efficiently from a power or fuel efficiency perspective at higher RPM, it will wear faster. Climbing out after takeoff I use 2500 RPM/25" MP and then 2400 RPM/24" MP for extended climb. I cruise between 2300 and 2400 RPM depending on the fuel burn that I want. The Lycoming engine performance table is useful as a guide to fuel burn but I find that it doesn't mean much in actual flight. What does it really mean in terms of true airspeed to fly at 65% power for example? Each Maule is different in terms of drag so power settings and fuel burn are going to vary all over the place to achieve a particular airspeed. The selection of a particular airspeed is a compromise between flight time and fuel burn. Since drag varies as the square of airspeed, does it really make sense to increase throttle by 100 RPM (fixed pitch) to gain 5 kts when fuel burn goes from 9 gph to 11 gph? You might get there 5 minutes earlier and burn 2 more gallons of fuel. The only time I push my engine is when I'm trying to beat sunset in the mountains since I like to see surrounding terrain and potential emergency landing spots when there's daylight.
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