The problem with Cessna 172's in Colorado.

[Tim Cobb]

I'm a new pilot but wanting to buy my first aircraft. I see lot of nice 172's on the market and they would serve my needs for the most part except. KFTG (Front Range Airport) is 5,500 MSL. This means the plane with 160 hp can't even haul 4 passengers on a warm day with a full load of fuel. The next step up is a Cessna 182 I guess. But more money and more fuel consumption. Anybody have any thoughts on this?

 

[bbchien]

A 160 hp plane with four adults and full fuel can't do that from sea level either.

If you want to haul 4 big guys and 80 gallons of fuel, you need at LEAST 230 hp (Sea level), maybe 260 or 300 hp (which at DEN is 230 hp).

It's more money but no more fuel consumption. You get up to 11,000 feet and the thing will only burn 11.5 (The 260 hp Cessna 205) or 10.0 (the 230 hp Cessna 182). Much less AIR up there to make the right, burnable mixture.

 

[Clark1961]

First off shave the goatee - that'll save you five pounds right there.

A 180 (or higher) horsepower 172 is really nice up here. A 180 Cherokee is also an option. Of course another option is to just fly within the limits of the aircraft that you decide to purchase. I bought a turbo Dakota so I wouldn't have to give up so much at high density altitudes.

 

[Tim Cobb]

LOL Can't shave the goatee its a part of me! Never seen a thicker or bushier one. Its a Colorado landmark and can be seen from space.

 

[Doggtyred]

I'm a new pilot but wanting to buy my first aircraft. I see lot of nice 172's on the market and they would serve my needs for the most part except. KFTG (Front Range Airport) is 5,500 MSL. This means the plane with 160 hp can't even haul 4 passengers on a warm day with a full load of fuel. The next step up is a Cessna 182 I guess. But more money and more fuel consumption. Anybody have any thoughts on this?

A general rule of thumb with general aviation planes is to consider them a compromise...

You can have full fuel... or full seats... but not both. There are very very few factory GA planes that can do both.

A C172 would be a good plane for 2 seats and full fuel with a long runway in Colorado.. A 180, 182 or 185 would be even better. That being said.. its not impossible to use a 172 to its maximum effectiveness.. A friend of mine moved to SLC from the coast with a Cessna 140 (yes.. the antique..).. and he was able to operate out there (it was tedious and you planned ahead) safely...


Now THAT is an example of a plane that flew on the wing, and not on the prop. You climbed by keeping the nose down, building speed, and letting increased speed increase your lift.

 

[CJones]

182 is a nice bird. The 182RG I flew would let you fill all 4 seats, camping gear for all 4 people (2 couples) and something around 80+ gals of fuel in the tanks (at 1,000' MSL). Oh, and it true'd out around 150kts.

One thing that some people don't consider is that airplanes come with a throttle control for a reason - you don't 'have' to run it at max cruise all the time. If you don't want to burn 13 gph in a 182, then pull the throttle back and burn 10 gph - sure you'll go slower, but if 172 speed is all you want/need then you can use the extra HP in a 182 for takeoff and climb, then pull the power back to 172 fuel burn and cruise numbers. With that said, though.... I don't know that I could make myself pull the throttle back.

 

[flyersfan31]

I'm a new pilot but wanting to buy my first aircraft. I see lot of nice 172's on the market and they would serve my needs for the most part except. KFTG (Front Range Airport) is 5,500 MSL. This means the plane with 160 hp can't even haul 4 passengers on a warm day with a full load of fuel. The next step up is a Cessna 182 I guess. But more money and more fuel consumption. Anybody have any thoughts on this?

How far are you travelling? Do you need full fuel loads with 4 pax?

How heavy are the pax you envision transporting? 4 200 pound dudes would keep any 4 seater I can think of on the ground.

With regard to fuel burn, remember, you may burn more fuel but in many planes you will also be going faster. 8 gph for 120ktas in a 160hp 172 vs 12gph for 145ktas in a 182. Since you get there quicker, you don't burn the full 4gph difference.

If you think you'll be hauling 4 big un's around often, think about a Cherokee 6. Still simple to fly. You'll need a HP endorsement but that's no big deal. That, or if you like high wings, a Cessna 206. A little more cramped, but great in the back country.

 

[COFlyBoy]

There are a lot of NTSB accident reports about people trying to fly fully loaded 172s in Colorado. I wouldn't try it, except maybe when it is really cold. Buy horsepower or a turbo if you really need to haul 4 people.

In the 6 I can take 4 200 lb dudes, 3 hours of gas and still be 450lbs under gross.

Don't push high DA ops in CO, you'll lose.

P.S. You should look at Platte Valley. It's only 10 minutes away.

 

[dmccormack]

You need a Cessna 205.

 

[Mtns2Skies]

If i'm one of your pax i'm alright 5'7" and a massive 120 pounds. Not prompting for a ride or anything

 

[wabower]

Yeah, read Martha Lunken's recent article in May's Flying Magazine. It's directly on point to your question. Her answer is simple. Either leave off some fuel or some pax.

I'm a new pilot but wanting to buy my first aircraft. I see lot of nice 172's on the market and they would serve my needs for the most part except. KFTG (Front Range Airport) is 5,500 MSL. This means the plane with 160 hp can't even haul 4 passengers on a warm day with a full load of fuel. The next step up is a Cessna 182 I guess. But more money and more fuel consumption. Anybody have any thoughts on this?

 

[rottydaddy]

If it's at all possible to fly out of KFTG on 160 hp with 4 adults but partial fuel, that doesn't seem too bad a compromise. Why burn more fuel just to haul more fuel, unless you're heading out over the ocean?

 

[murphey]

A 160 hp plane with four adults and full fuel can't do that from sea level either.

If you want to haul 4 big guys and 80 gallons of fuel, you need at LEAST 230 hp (Sea level), maybe 260 or 300 hp (which at DEN is 230 hp).

It's more money but no more fuel consumption. You get up to 11,000 feet and the thing will only burn 11.5 (The 260 hp Cessna 205) or 10.0 (the 230 hp Cessna 182). Much less AIR up there to make the right, burnable mixture.

Bruce:

11K around here in the summer is barely enough to fly Denver - Pueblo. Please understand that there are times when density altitude is 9K on the ground.

 

[murphey]

Tim:

Think about what your mission is. Will you always be taking a full aircraft or only rarely? If it's rarely, then the 172 is fine then you get a high-performance add-on and rent the 182 or whatever when you need to take more mass. On the other hand, if you need to carry those 4 adults & gear, then you must look at the Piper Dakota/235 or the Cessna 182/206/etc.

Remember, just because there's 4 seats doesn't mean you can put 4 bodies there.

Got Sat, June 12 free? Take the Colorado Pilots Assoc. High-Altitude Airport (aka Mountain Flying) course. It's all day ground (counts as Wings and I think BFR when you take the all-day practical) that goes into excruciating detail about this. (yes, I'm shilling)

I've got 180 hp and the only time I take 4 people is when 2 are small or children. I've had 3 adults & full fuel (50 gal) and max gross (2400 lbs) at sea level, it was ok. After the first fuel stop, never did fill up again (36 gal). Up here, no way.

 

[flyingcheesehead]

172's don't haul 4 people and full fuel anywhere.

There's two ways to get sea level performance where you are: Keep the plane light enough that your power loading (pounds per hp) is the same as at sea level, or get something with a turbo. You'll still use more runway there than at sea level, but you'll be able to climb better.

I took off from Leadville at about 300 under gross with a DA of 12,200 and used 2000 feet of runway in a normally aspirated 182. I also got it to climb to 17,500 (DA of 18,848) at about the same weight, and it was able to climb at 500 fpm up to 15,300. So, if those numbers work for you, get a 182. If you want to take three buddies camping for the weekend, get a turbo 182.

 

[wabower]

I fly with the power pulled back all the time. If you're not going anywhere anyway, what's the hurry to not get there?

182 is a nice bird. The 182RG I flew would let you fill all 4 seats, camping gear for all 4 people (2 couples) and something around 80+ gals of fuel in the tanks (at 1,000' MSL). Oh, and it true'd out around 150kts.

One thing that some people don't consider is that airplanes come with a throttle control for a reason - you don't 'have' to run it at max cruise all the time. If you don't want to burn 13 gph in a 182, then pull the throttle back and burn 10 gph - sure you'll go slower, but if 172 speed is all you want/need then you can use the extra HP in a 182 for takeoff and climb, then pull the power back to 172 fuel burn and cruise numbers. With that said, though.... I don't know that I could make myself pull the throttle back.

 

[bbchien]

Bruce:

11K around here in the summer is barely enough to fly Denver - Pueblo. Please understand that there are times when density altitude is 9K on the ground.

I lived and flew for a few years from Flagstaff, 7011 MSL. Tell me about it. Pilots also need to distinguish Pressure altitude (which determines POWER - all that the engine needs is absolute partial pressure of Oxygen molecules to make power) and Density altitude, which determines how the airframe flies. If you look at a density altitude performance chart, 10,700 is very common at FLG.

I'm happy Tim is asking, because he doesn't really understand the issue. For his four big guys and fuel task, he needs a Cessna 205....with two seats out, and with gear, he'll need a turbo or a really long runway with a really slow climb. Vy (75 mph) in the Cessna 205 is actually 89 mph into wind at 7000 feet.

At FLG, you have 70% of power available for departure. 260 hp (IO470U) x .7 = 182 hp. You have a smidgen more power available at FTG, elev 5512 (about 76%).

 

[dmccormack]

You need a Cessna 205.

I'm happy Tim is asking, because he doesn't really understand the issue. For his four big guys and fuel task, he needs a Cessna 205....with two seats out, and with gear, he'll need a turbo or a really long runway with a really slow climb. Vy (75 mph) in the Cessna 205 is actually 89 mph into wind at 7000 feet.

Yep!!

Perfect airplane for folks that need to haul stuff, but don't want the complexity or cost of turbocharging and pressurization (Though IIRC Vy is 96 MPH and Vx is 78 MPH).

There's a reason 205s remain popular out west.

 

[gismo]

I lived and flew for a few years from Flagstaff, 7011 MSL. Tell me about it. Pilots also need to distinguish Pressure altitude (which determines POWER - all that the engine needs is absolute partial pressure of Oxygen molecules to make power) and Density altitude, which determines how the airframe flies.

Bruce, you've got that wrong (and I must admit I'm surprised, but flying turbos has apparently rotted your brain a tiny bit). DA has the same effect on engine power with any normally aspirated engine, it's the number of O2 molecules per second ingested by the engine that determines available HP, not the partial pressure of the O2.

 

[Tim Cobb]

Thanks for all the great comments! The 182 does seem like a good step up from the 172.

 

[Clark1961]

Bruce, you've got that wrong (and I must admit I'm surprised, but flying turbos has apparently rotted your brain a tiny bit). DA has the same effect on engine power with any normally aspirated engine, it's the number of O2 molecules per second ingested by the engine that determines available HP, not the partial pressure of the O2.

Hmmm I seem to recall that Ppi = yi*P

In other words the partial pressure of a component is equal to the mole fraction of that component multiplied by the total pressure. In more other words the partial pressure is a measure of the number of molecules of a particular component. As always YMWV.

 

[Anthony]

I was based at Front Range, KFTG, for three years with my Tiger which is 180HP. In the summer, I used it strictly as a two place plane. When I flew it to Leadville, the flight school was operating a 150 HP 172 at a beginning altitude of 10,000 ft and it worked fine. Again, this is with two people maximum, with a VERY experienced mountain flying instructor.

The C-182 is considered one of the best non-turbo choices in the high altitude west as it give you the flexibility to carry a bit more and have the performance necessary to overcome most of the DA situations year round with two - three people and some baggage. To me it is still not a four place plus bags plane in the summer.

Did you take the Colorado Pilots Assoc. Mountain Flying Course yet? If not, do so.

 

[Danos]

I have nothing to add except to say that your goatee is supreme!

 

[colomtnflyer]

Though it's still not going to get 4 big guys and fuel off the ground, I'm suprised there has been no mention of a C172XP, with 210HP and a constant spd prop. It certainly adds a bit of useful and some speed, but it does suck a little more fuel.
But if the guys are full sized, then the 172 cabin becomes a comfort issue, whereas the 182 cabin has considerably more room.

 

[tonycondon]

chris it helped that we have small wives.

 

[steingar]

I think the OP has discovered the problem with a lot of sub 200hp aircraft out west. Not a huge surprise, those rocks are BIG.

 

[Everskyward]

I think the OP has discovered the problem with a lot of sub 200hp aircraft out west. Not a huge surprise, those rocks are BIG.

Even without the rocks the elevations in the Denver area are 5000-6000 MSL and it frequently gets into the 80s in the summer and occasionally into the 90s.

 

[brcase]

Thanks for all the great comments! The 182 does seem like a good step up from the 172.

yep, it is hard to go wrong with a 182.
You can find many airplanes that are better in one aspect or another but it is difficult to find one that is a versatile as a 182.

Brian

 

[wabower]

As did we all . . . once.

And they had lean athletic husbands. And at one time my weight and balance for both of us, plus bags and golf clubs, was ~350#. *snort*

chris it helped that we have small wives.

 

[dmccormack]

Though it's still not going to get 4 big guys and fuel off the ground, I'm suprised there has been no mention of a C172XP, with 210HP and a constant spd prop. It certainly adds a bit of useful and some speed, but it does suck a little more fuel.
But if the guys are full sized, then the 172 cabin becomes a comfort issue, whereas the 182 cabin has considerably more room.

Just talked to a guy this Saturday with a 180 Lycoming-powered 172 with CS prop...

Kinda threw me off when i first looked at it.

 

[bbchien]

Bruce, you've got that wrong (and I must admit I'm surprised, but flying turbos has apparently rotted your brain a tiny bit). DA has the same effect on engine power with any normally aspirated engine, it's the number of O2 molecules per second ingested by the engine that determines available HP, not the partial pressure of the O2.

Well you're literally correct! But for takeoff we're basically talking max "diplacement per second at 2650 rpm" or the like. If that is held constant, power will be proportionate to the absolute pressure of O2.

Now I will admit to some instances of brain rot.....

 

[Tim Cobb]

I have nothing to add except to say that your goatee is supreme!

LOL well thanks! I can grow some serious facial hair for some reason. I use a weed whacker to trim it.

 

[murphey]

I was based at Front Range, KFTG, for three years with my Tiger which is 180HP. In the summer, I used it strictly as a two place plane. When I flew it to Leadville, the flight school was operating a 150 HP 172 at a beginning altitude of 10,000 ft and it worked fine. Again, this is with two people maximum, with a VERY experienced mountain flying instructor.

The C-182 is considered one of the best non-turbo choices in the high altitude west as it give you the flexibility to carry a bit more and have the performance necessary to overcome most of the DA situations year round with two - three people and some baggage. To me it is still not a four place plus bags plane in the summer.

Did you take the Colorado Pilots Assoc. Mountain Flying Course yet? If not, do so.

GROUND SCHOOL CONTENT: The ground school covers the basics necessary for flight in mountainous areas, including:

• Mountain weather phenomena
• Flight planning for mountain flying
• Density altitude
• High altitude performance
• Off-airport landings
• Mountain winds
• Mountain airport arrivals
• Enroute navigation
• Emergency planning
• Proper leaning procedures
• Mountain airport departures

This program has been approved by the FAA as both a Wings event and also counts as a BFR (if you need one) when you complete both the full-day ground school and the optional full-day practical flight (taken at mutual convenience with one of the CPA Mountain Flight CFIs.)

Sign up at:
http://coloradopilots.org/registration.asp?event_id=MtnFlying-2010

 

[Trapper John]

Just talked to a guy this Saturday with a 180 Lycoming-powered 172 with CS prop...

Kinda threw me off when i first looked at it.

Avcon or Bush conversion, probably. The Penn Yan and Air Plains 180 hp conversions are fixed pitch. I'm not sure there's a whole lot of benefit to the cost and weight of a CS prop on a 172 myself.

 

[dmccormack]

Avcon or Bush conversion, probably. The Penn Yan and Air Plains 180 hp conversions are fixed pitch. I'm not sure there's a whole lot of benefit to the cost and weight of a CS prop on a 172 myself.

He said there's no MGW increase (though there's an STC available to increase it), but the real advantage is takeoff performance. Otherwise its 10 GPH @ 115 knots.

 

[Trapper John]

He said there's no MGW increase (though there's an STC available to increase it), but the real advantage is takeoff performance. Otherwise its 10 GPH @ 115 knots.

Oh, I agree the extra HP is a good thing, I'm just not convinced that adding a CS prop to a 180 hp 172 really adds anything useful.

 

[dmccormack]

Oh, I agree the extra HP is a good thing, I'm just not convinced that adding a CS prop to a 180 hp 172 really adds anything useful.

Yeah -- sorta like VGs on a 172 -- really?

 

[COFlyBoy]

Oh, I agree the extra HP is a good thing, I'm just not convinced that adding a CS prop to a 180 hp 172 really adds anything useful.

It probably shortens the takeoff run a bit. It is probably more noticeable in Denver than at sea-level.

Given the low ambient pressure and a static RPM of say 2350, your fixed pitch 172 may only be generating 80% of rated power during the start of the take-off run. With a CS prop, maybe you can get that up to 90-95%.

In "The 6" I generally see 25-26 in. MAP at 2700 RPM on take-off

 

[Trapper John]

It probably shortens the takeoff run a bit. It is probably more noticeable in Denver than at sea-level.

Given the low ambient pressure and a static RPM of say 2350, your fixed pitch 172 may only be generating 80% of rated power during the start of the take-off run. With a CS prop, maybe you can get that up to 90-95%.

It's really thrust that makes the plane go, so you need to relate thrust developed along the takeoff path to compare different engine/prop combinations.

 

[COFlyBoy]

It's really thrust that makes the plane go, so you need to relate thrust developed along the takeoff path to compare different engine/prop combinations.

True, and the constant speed prop (assuming similar prop efficiencies) will always generate more thrust during the takeoff run than a fixed pitch prop simply because the engine is producing max power during the entire takeoff roll. Whereas a fixed pitch prop engine combo will not generate max power until you hit whatever the prop critical speed is.

The major advantage of CS props is that they allow the engine to operate at maximum power during all flight regimes. You are trading a little weight and complexity for increased power.