Piper Arrow Gross weight - High altitude

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Mtns2Skies

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Mtns2Skies
After seeing the other thread regarding gross weight flying it brought up a question.

I'll be taking a piper arrow to oshkosh and we'll be departing at gross weight from an airport elevation of 5000ft.

The runway is 8500ft long. we'll be departing at 6am.

The POH says in theory we'll be off the ground in 3-4thousand feet of runway.

Any experience with naturally aspirated arrows at altitude at gross? Will it fly OK? Will it takeoff OK? Is it relatively safe?

It's a rented aircraft - Are there any good ways add that significant amount of weight without the people/fuel/bags for practice?
 
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I think the word "lethargic" will describe how it'll perform. Hell, a heavy Arrow III at gross with a DA of 2500 feet barely gets out of its own way. I think an arrow would do well with an o540.
 
Mtns2Skies said:
After seeing the other thread regarding gross weight flying it brought up a question.

I'll be taking a piper arrow to oshkosh and we'll be departing at gross weight from an airport elevation of 5000ft.

The runway is 8500ft long.

The POH says in theory we'll be off the ground in 3-4thousand feet of runway.

Any experience with naturally aspirated arrows at altitude at gross? Will it fly OK? Will it takeoff OK?
Click to expand...

Leave early in the morning when it is cool.

There are several flavors of NA Arrows and then there is the maintenance condition. The 200 hp Arrow I flew had a fuel divider problem (we found out later) and wasn't much of a performer. In general it should make close to book numbers but you prolly know that.

There's nothing quite like the long taxi for departure on a high, hot day with a naturally aspirated engine. Fly the numbers and don't force it off the ground.
 
540 would be great 520 would be too. As for the performance mine pretty much does what the book says. You don't say if it is a III or a II. The III has a 2750 gross weight, not sure what the II has.
 
Three blade may help climb

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Interesting question, I have no experience in an arrow nor do I have much high DA experience. But I do have a few instances where I was at gross or close to in my former plane (235).

What I have done is, instead of rotating at 65MPH I will rotate at 75MPH and then build a little more speed in ground effect until I have reached about 95-100mph before I start my climb.

I guess given your situation thats what I would do, terrain permitting. With a 9k runway, you should have no problem building speed for your climb.
 
I just did this out of Durango, CO (6685 elevation, 9000 runway). I fly a 180 hp Mooney. My strategy was...
1. Leave early. DA was basically field elevation at 6:15am.
2. Leave some gas behind. I left about 15 gal. behind which saved almost 100 lbs. You have to make a fuel stop anyway, just make one sooner at lower elevation.
3. No flaps takeoff for more airspeed on the ground. Long runway, no rising terrain, so number one issue became engine temps on the climb. By building more speed on the ground, and climbing slowly, I kept temps down and easily climbed out to cruise at 11500.

Anyway, that worked out well for us.
 
If you know what you are doing (and if you are regularly renting in Ft Collins you should; if not speak with your instructors) an Arrow will perform as well as any other normally-aspirated airplane in those conditions and subject to the same warnings about densnity altitude and flying at max gross.

I've flown a normally-aspirated Arrow from KAPA to KAEG and had no problems over much higher terrain than you will encounter (it was in October for the Balloon Fiesta so it was cooler that it would be expected in July but still..) Besides, once you get to altitude after takeoff at KFNL, it will be downhill all the way.

I see you have thought about a test flight loading the airplane with equivalent weight? Perhaps with an instructor? Sandbags, heavy suitcases or backpacks, people, most anything can be used to simulate the weight you want.
 
Arbiter419 said:
I think the word "lethargic" will describe how it'll perform. Hell, a heavy Arrow III at gross with a DA of 2500 feet barely gets out of its own way.
Click to expand...

I agree. It will climb like a lead brick. Just keep it on the ground about 5 knots past rotate. It will climb out of ground effect better. Be prepared to see 500' fpm or less in the climb.
 
Mtns2Skies said:
After seeing the other thread regarding gross weight flying it brought up a question.

I'll be taking a piper arrow to oshkosh and we'll be departing at gross weight from an airport elevation of 5000ft.

The runway is 8500ft long. we'll be departing at 6am.

The POH says in theory we'll be off the ground in 3-4thousand feet of runway.

Any experience with naturally aspirated arrows at altitude at gross? Will it fly OK? Will it takeoff OK? Is it relatively safe?

It's a rented aircraft - Are there any good ways add that significant amount of weight without the people/fuel/bags for practice?
Click to expand...
What are you used to flying? If a LSA, go take a CFI along to see the difference.
The POH is clueless for,our altitudes. You live up here, so you understand leaning....just remember to "unlean" the further east you go. Also expect a bit longer departure roll. No big deal.

You'll be astonished at performance when you leave.
 
Lethargic but doable. I've flown my Arrow II out of KTVL (6,300' elevation) on a hot Summer day without issues. It's best to treat it as a soft field takeoff - get off the ground, gear up, stay in ground effect for acceleration terrain and field permitting, and be prepared for a slow climbout.

I've flown my Turbo Arrow plenty of time out of the same airport. Climb performance isn't great but climb performance isn't much better at sea level to begin with.
 
murphey said:
What are you used to flying? If a LSA, go take a CFI along to see the difference.
The POH is clueless for,our altitudes. You live up here, so you understand leaning....just remember to "unlean" the further east you go. Also expect a bit longer departure roll. No big deal.

You'll be astonished at performance when you leave.
Click to expand...

Used to flying at KBJC/KFNL my whole life in Just about all single engine 4-place planes you can rent in the area. Flown Diamonds, 40 hours in Arrows, 40 hours in 182's bunch of hours in 172's and 172RG's, Citabria's. I've done all of the mountain flying training and regularly fly out to Grandby over Rollins.

Just never had a need to fly at or anywhere near gross weight before so I'm just unfamiliar with that aspect.
 
Lean to max power. Take off, accelerate to Vy in ground effect, then climb at Vy. If you can leave some fuel or your extra change of socks behind, it'll help.
 
Mtns2Skies said:
Used to flying at KBJC/KFNL my whole life in Just about all single engine 4-place planes you can rent in the area. Flown Diamonds, 40 hours in Arrows, 40 hours in 182's bunch of hours in 172's and 172RG's, Citabria's. I've done all of the mountain flying training and regularly fly out to Grandby over Rollins.

Just never had a need to fly at or anywhere near gross weight before so I'm just unfamiliar with that aspect.
Click to expand...

If you have to come back and land, don't get slow early as the bottom tends to drop out rather abruptly. you'll be able to keep the nose up but it develps a high sink rate really fast compared to what you're used to.
 
SmashTime said:
Interesting question, I have no experience in an arrow nor do I have much high DA experience. But I do have a few instances where I was at gross or close to in my former plane (235).

What I have done is, instead of rotating at 65MPH I will rotate at 75MPH and then build a little more speed in ground effect until I have reached about 95-100mph before I start my climb.

I guess given your situation thats what I would do, terrain permitting. With a 9k runway, you should have no problem building speed for your climb.
Click to expand...

Any time you're not at Vy in this scenario, you're wasting energy. I know it's not much, but I would be flying the numbers from the performance calculations all the way up through the take off.

To the OP -
Wheels up in the early morning
Leave some fuel behind
Run the numbers (with a conservative fudge factor, I'm not a Chuck Yeager and you probably aren't either)
Lean for best power

Have fun!
 
I just plotted out 75* and 6000 DA, 0 kts headwind, 61 kt rotation and came up with a take off distance of 3700' at 2750# or gross with 25* flaps, and with 0* flaps I get 71 kt rotation and a take off roll of 3750'.

I would go no flaps.

One thing to remember if the auto extension is not removed from that aircraft is to disable it so the gear will come up before the approximate 75 kts of air speed.
 
Mtns2Skies said:
Used to flying at KBJC/KFNL my whole life in Just about all single engine 4-place planes you can rent in the area. Flown Diamonds, 40 hours in Arrows, 40 hours in 182's bunch of hours in 172's and 172RG's, Citabria's. I've done all of the mountain flying training and regularly fly out to Grandby over Rollins.

Just never had a need to fly at or anywhere near gross weight before so I'm just unfamiliar with that aspect.
Click to expand...
I kind of hoped you were talking about unfamiliarity with the airplane or OP's at ir near gross. If that - gross weight OP's - is not something you've experienced, it is something you want to try out in a controlled anvironment before you do it with the pressures of wanting to get there. That would be true even at sea level.
 
You'll get off and turn east You'll be fine. All downhill from there. Three in an Arrow, IFR to Santa Fe and Denver approach asked if we'd left Fort Collins yet. Joke that they tubocharged the Arrow to keep up to Mooneys:)
 
SmashTime said:
Interesting question, I have no experience in an arrow nor do I have much high DA experience. But I do have a few instances where I was at gross or close to in my former plane (235).

What I have done is, instead of rotating at 65MPH I will rotate at 75MPH and then build a little more speed in ground effect until I have reached about 95-100mph before I start my climb.

I guess given your situation thats what I would do, terrain permitting. With a 9k runway, you should have no problem building speed for your climb.
Click to expand...

:confused: Why? Vy does not change with DA since IAS is self correcting at the pitot.:dunno: Basically you are giving up rate of climb for airspeed. This may help if you have cooling issues in the climb, but does not help the climb itself.
 
Henning said:
:confused: Why? Vy does not change with DA since IAS is self correcting at the pitot.:dunno: Basically you are giving up rate of climb for airspeed. This may help if you have cooling issues in the climb, but does not help the climb itself.
Click to expand...
Most POH will show Vy decreasing and Vx increasing with altitude (not that much but it's there) until they meet at the airplane's service ceiling. We fly the same approach speed regardless of altitude because IAS is self-correcting. But Vx and Vy involve more than just the pitot tube.

Not sure of his reasoning for a delayed rotation, though. I do understand getting into ground effect in very high density altitude situations but that's usually done at a lower rotation speed, not a higher one.
 
Henning said:
:confused: Why? Vy does not change with DA since IAS is self correcting at the pitot.:dunno: Basically you are giving up rate of climb for airspeed. This may help if you have cooling issues in the climb, but does not help the climb itself.
Click to expand...

Vy does indeed change with altitude, and trying to climb faster than that in a PA28 at 10,000 DA is not fun at all. BTDT, and 5 knots makes a huge difference in climb rate. It will do it with only slightly positive climb rate when using a sea level Vy. It's still weak but much more comfortable at the correct Vy.

There are several available descriptions why it changes, related to the shape of the power curve. In a nutshell, drag force is due to true (not indicated) airspeed and it is a very strong function, so the higher true airspeed will push Vy down. For fixed pitch, there is another prop efficiency effect, but an Arrow isn't fixed pitch.
 
midlifeflyer said:
Most POH will show Vy decreasing and Vx increasing with altitude (not that much but it's there) until they meet at the airplane's service ceiling. We fly the same approach speed regardless of altitude because IAS is self-correcting. But Vx and Vy involve more than just the pitot tube.

Not sure of his reasoning for a delayed rotation, though. I do understand getting into ground effect in very high density altitude situations but that's usually done at a lower rotation speed, not a higher one.
Click to expand...

True, but the relationship would be opposite with Vy decreasing, so it makes it even worse.
 
Even light, an Arrow doesn't perform very well in take offs over 7000' IME.
 
midlifeflyer said:
Most POH will show Vy decreasing and Vx increasing with altitude (not that much but it's there) until they meet at the airplane's service ceiling. We fly the same approach speed regardless of altitude because IAS is self-correcting. But Vx and Vy involve more than just the pitot tube.
Click to expand...

Just as an example, on the 'kota I get best rate of climb about 4 knots slower than the book Vy on a hot day at FTG.
 
Mtns2Skies said:
After seeing the other thread regarding gross weight flying it brought up a question.

I'll be taking a piper arrow to oshkosh and we'll be departing at gross weight from an airport elevation of 5000ft.

The runway is 8500ft long. we'll be departing at 6am.

The POH says in theory we'll be off the ground in 3-4thousand feet of runway.

Any experience with naturally aspirated arrows at altitude at gross? Will it fly OK? Will it takeoff OK? Is it relatively safe?

It's a rented aircraft - Are there any good ways add that significant amount of weight without the people/fuel/bags for practice?
Click to expand...

I've departed several times in my Arrow 2 from 6800' feet (KSRR) in the mornings, but I've always been at least 100 pounds under gross. One time I had a problem raising the gear, and my climb performance was under 100 fpm.

If your aircraft has an auto-extender, be sure it is OFF prior to takeoff, or risk
the fruits of not being able to climb should it prevent gear retraction.
 
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