talk about stalls

[dkkim73]

1 hour ago, Shadrach said:

I built an aircraft specific spreadsheet long ago that calculates stall and approach speeds in all configurations at any weight and bank angle up to 60°. I was actually curious about the weight range of his aircraft for normal single pilot ops. Normal single pilot ops for me is is between 2000 and 2100lbs (200lb pilot, two hours of fuel remaining and 20 to 40lbs of stuff/baggage). Under those conditions, I’m crossing the threshold of 55kias. 
 

If @dkkim73 is crossing the fence at 70kias, I’m guessing he weighs around 2700lbs for that target speed.

Heavier than I want, but less than 2700 lbs unless you are including the plane!!! Seriously, though, I probably don't like to operate with much below 24-30 gals in the tank, so call it 2800 at lowest weights. On commutes, I may be landing close to 3200lbs (MLDW) when tankering fuel. I keep it closer to 75 heavy and 70 light. Once within a few feet of the runway, it's comfortable to slow down a lot more. Generally don't go below 80KIAS while maneuvering or reconfiguring. A "designated min. maneuvering speed" (1.4Vs) would seem to be 75-90KIAS based on configuration. So 80-85 until established on final, then trying to slow and stabilize, adjust angle as required. 

55KIAS sounds really slow until in ground effect. 

[exM20K]

1 hour ago, Shadrach said:

I built an aircraft specific spreadsheet long ago that calculates stall and approach speeds in all configurations at any weight and bank angle up to 60°. I was actually curious about the weight range of his aircraft for normal single pilot ops. Normal single pilot ops for me is is between 2000 and 2100lbs (200lb pilot, two hours of fuel remaining and 20 to 40lbs of stuff/baggage). Under those conditions, I’m crossing the threshold of 55kias. 
 

If @dkkim73 is crossing the fence at 70kias, I’m guessing he weighs around 2700lbs for that target speed.

A 2700# Acclaim with a 200# pilot has a few cups of fuel.

70 KIAS is fine 2900-3000# in good conditions.

-dan

[Shadrach]

12 minutes ago, Hank said:

Huh???

Stall strips hasten the stall in the area where they are installed by causing boundary layer separation aft of the strip. It causes a consistent localized stall ahead of the break and a pronounced buffet. 

[Shadrach]

1 hour ago, dkkim73 said:

Heavier than I want, but less than 2700 lbs unless you are including the plane!!! Seriously, though, I probably don't like to operate with much below 24-30 gals in the tank, so call it 2800 at lowest weights. On commutes, I may be landing close to 3200lbs (MLDW) when tankering fuel. I keep it closer to 75 heavy and 70 light. Once within a few feet of the runway, it's comfortable to slow down a lot more. Generally don't go below 80KIAS while maneuvering or reconfiguring. A "designated min. maneuvering speed" (1.4Vs) would seem to be 75-90KIAS based on configuration. So 80-85 until established on final, then trying to slow and stabilize, adjust angle as required. 

55KIAS sounds really slow until in ground effect. 

Same basic airframe with very different wing loading and fuel burn.  Thats why I figured you at 2700ish.
20 gals is 2 hours of fuel at cruise for me, so pretty conservative reserves for the end of an XC flight

55kias is slow for the pattern but not for the threshold. I want to be at 1.2xVso over the numbers. At 2000lbs, calculated Vso is ~46kts (less in ground effect). 

[Pinecone]

The main purpose of stalls strips are to cause that part of the wing to stall first.  They are typically inboard to make sure the root area stalls first for a more stable stall.  The buffet comes from the stall, whether there are stall strips or not.

The original configuration of the Piper Tomahawk had only outboard stalls strips.  It has a bit of a lively stall and spin entry.  The spin entry was pretty much a 1/2 snap roll then the nose dropped as it continued to roll and become a spin. Piper did add inboard stall strips to make it a bit more docile.

I did my CFI spin endorsement in an outboard only stall strip Tomahawk.  GREAT fun.

 

[Shadrach]

12 hours ago, Pinecone said:

The main purpose of stalls strips are to cause that part of the wing to stall first.  They are typically inboard to make sure the root area stalls first for a more stable stall.  The buffet comes from the stall, whether there are stall strips or not.

The original configuration of the Piper Tomahawk had only outboard stalls strips.  It has a bit of a lively stall and spin entry.  The spin entry was pretty much a 1/2 snap roll then the nose dropped as it continued to roll and become a spin. Piper did add inboard stall strips to make it a bit more docile.

I did my CFI spin endorsement in an outboard only stall strip Tomahawk.  GREAT fun.

 

A stall will always cause a buffet. A stall strip will cause buffet that occurs further ahead of the break. I’ve never removed a strip to see the difference in the buffet. I’m simply relaying what I’ve read how they work and what they do. 

[Fly Boomer]

11 hours ago, Hank said:

Huh???

"I was under the impression that most GA aircraft had stall strips. Stall strips yield a pronounced buffet before the wing breaks."

If you select the text, you can read it.

[A64Pilot]

12 hours ago, Hank said:

Old Mooneys have small rudder, stopping the horizontal stabilizer. Around 1965 or 66 or so, the rudder was pushed all the way to the bottom of the vertical stabilizer. So not exactly a "more modern nose wheel airplane. "

Smaller, shorter, lighter airplanes with less HP.

As they got bigger and especially longer and more power they needed more rudder I’m sure to pass Certification and as they could go down it was most logical as opposed to increasing cord. Going down also increases rudder authority with less roll imparted, and often you need the roll to pass Cert as one requirement is that you must be able to lift a dropped wing with rudder only. To pass that is very often why more modern aircraft often have aileron / rudder interconnects.

”Old” design aircraft were designed to and expected to be spun, spinning back in the day was considered to be a normal thing for smaller single engine airplanes. It wasn’t until later that spins were to be avoided and that trend has continued until we have reached the point where airplanes if a spin is inadvertently entered may not be recoverable, so we need parachutes to get an equal level of safety

You may not, but I consider a Mooney a modern design, heck most even consider a Bonanza a modern design and it first flew in 1946 I think?

I’ve not measured my little 140’s rudder area but think it has as much as my Mooney, and the little 140 has a half ton less Gross weight and at 85 HP well less than half the HP.

Old school would often be prior to WWII and or soon after. Sadly believe it or not but there hasn’t been much advancement in small aircraft design, we literally fly our Grandfathers aircraft. Even the most modern aircraft like say a Cirrus really isn’t in truth very advanced, for whatever reason we never did adopt designs like Routan’s etc.

[Pinecone]

6 hours ago, Shadrach said:

A stall will always cause a buffet. A stall strip will cause buffet that occurs further ahead of the brake. I’ve never removed a strip to see the difference in the buffet. I’m simply relaying what I’ve read how they work and what they do. 

The stall strip causes the flow to trip and have a localized area of the wing stalled at a LOWER AOA than without the strip.

Yes, a stall causes a buffet, but there are airplanes where the stall occurs at an AOA below that of the buffet.  NOT normal GA aircraft.

[varlajo]

15 hours ago, Shadrach said:

I built an aircraft specific spreadsheet long ago that calculates stall and approach speeds in all configurations at any weight and bank angle up to 60°. I was actually curious about the weight range of his aircraft for normal single pilot ops. Normal single pilot ops for me is is between 2000 and 2100lbs (200lb pilot, two hours of fuel remaining and 20 to 40lbs of stuff/baggage). Under those conditions, I’m crossing the threshold of 55kias. 
 

If @dkkim73 is crossing the fence at 70kias, I’m guessing he weighs around 2700lbs for that target speed.

Yep, same here, for my 71E (in mph)

Edited August 27 by varlajo

[Shadrach]

38 minutes ago, varlajo said:

Yep, same here, for my 71E (in mph)

Nice. Mine is a bit more crude but I just uploaded the latest version.

 

 

[Shadrach]

2 hours ago, Fly Boomer said:

"I was under the impression that most GA aircraft had stall strips. Stall strips yield a pronounced buffet before the wing breaks."

If you select the text, you can read it.

Is my post not readable?

[Shadrach]

50 minutes ago, Pinecone said:

The stall strip causes the flow to trip and have a localized area of the wing stalled at a higher AOA than without the strip.

Yes, a stall causes a buffet, but there are airplanes where the stall occurs at an AOA below that of the buffet.  NOT normal GA aircraft.

I think you meant lower.

[Hank]

1 hour ago, Shadrach said:

Is my post not readable?

No, it's just three solid black lines.

[Shadrach]

27 minutes ago, Hank said:

No, it's just three solid black lines.

Weird.  I saw this happen to half of one of @MikeOH's posts.  It looks like it's a dark vs light mode thing... It looks perfectly normal in dark mode.

 

[MikeOH]

@Shadrach

Right you are!  I went to 'dark mode' and your post showed up with no problem.

I use an iPad; no idea if that has any bearing on the issue but many other people don't seem to have a problem.  Did you use any special formatting on that post?

[Shadrach]

10 minutes ago, MikeOH said:

@Shadrach

Right you are!  I went to 'dark mode' and your post showed up with no problem.

I use an iPad; no idea if that has any bearing on the issue but many other people don't seem to have a problem.  Did you use any special formatting on that post?

No. In fact, I go out of my way to remove formatting because it's annoying when I try to read posts that are mis-formatted. 

Whenever I paste, I get a prompt that says:

Pasted as rich text.   Paste as plain text instead 

I always chose plain.

[MikeOH]

16 minutes ago, Shadrach said:

No. In fact, I go out of my way to remove formatting because it's annoying when I try to read posts that are mis-formatted. 

Whenever I paste, I get a prompt that says:

Pasted as rich text.   Paste as plain text instead 

I always chose plain.

Interesting.  I never get that prompt when I paste.

[Shadrach]

26 minutes ago, MikeOH said:

Interesting.  I never get that prompt when I paste.

Looks like this:

[Pinecone]

4 hours ago, Shadrach said:

I think you meant lower.

Oops.

 

Fixed

 

[Shadrach]

17 hours ago, Pinecone said:

Oops.

 

Fixed

 

I’m here to read what you say and ensure that you say what you mean…

at least you know someone is paying attention.

[Pinecone]

16 hours ago, Shadrach said:

I’m here to read what you say and ensure that you say what you mean…

at least you know, someone is paying attention.

Thank you for that.