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BrianW

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You could learn a thing or two by looking at that old plain-jane workhorse - the Cessna 150.
1) Stall warning. cut a vertical slot in the wing leading edge. Blank it with a curved cover which is adjustable in height and leads to a pipe to the cockpit end which is fitted with a pipe organ reed that sounds when sucked. Adjust the slot so it sounds 2 or 3 mph above stall AoA
2) Parking brake. arrange a hinged flap secured to structure at the hinge line through which the brake master cylinder rod passes. Arrange a spring on the flap so the rod can move through the hole freely.
Arrange a bowden wire cable to pull against the spring & flap when a cockpit control is pulled.
Push the brake pedal; pull the brake knob; release the pedal; release the control. The rod now wishes to extend, but is jammed by the brake flap.
Both of these devices weigh next to nothing, and keep working for 50+ years. You could not design something more efficient AND lighter, in your dreams.
 

BJC

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2) Parking brake. arrange a hinged flap secured to structure at the hinge line through which the brake master cylinder rod passes. Arrange a spring on the flap so the rod can move through the hole freely.
Arrange a bowden wire cable to pull against the spring & flap when a cockpit control is pulled.
Push the brake pedal; pull the brake knob; release the pedal; release the control. The rod now wishes to extend, but is jammed by the brake flap.
Well, we will just have to disagree about the C150 parking brake, which I consider to be a PoS.


BJC
 

Victor Bravo

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I can assist you with simplicating the Cessna even further.

First, remove the pipe organ reed and its ducting. Donate it to the baseball stadium, or perhaps the local church, wherever pipe organs are still being used.

Then remove the doubler (if there is one) around the hole that you cut in the wing leading edge skin. (If you can, don't cut the skin in the first place)

Now, cheerfully begin to enjoy the startling performance and fuel savings that you have gained from the weight reduction, and use the cost reduction (in aircraft construction time by not having to put that entire system in place) to buy your grand-children an ice cream cone.

You may then use the stall warning system that was thoughtfully built into the 150's design - by the nice old folks who stole the Cessna 100 series design from Don Luscombe. Instead of hearing a pipe organ sound, you will feel a rumbling and shaking through the airframe as you approach a stall.
 
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plncraze

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This is why I love the internet! Instead of tapered outer wing panels lengthen the inner rib of the outer wing panel for a saw tooth and enjoy a free vortex. The 150 is the Luscombe of the new millennium. Cheap and simple.
 

TFF

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I didn’t know there were still any parking brakes on 150s anymore. I thought they were all removed.
 

Twodeaddogs

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Well, Reinhold Platz designed the original Fokker Triplane to have no interplane struts but Fokker supposedly told him to fit them, to stop the pilots fretting. When you look at all the heavily strutted aircraft that came afterwards, I guess the concept of keeping things simple went out the window.
 

cluttonfred

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Hehe, that reminds me of the neat little Fokker V.40 we have discussed before, about as simple as you can get with that sort of approach.

1604407928932.png

Well, Reinhold Platz designed the original Fokker Triplane to have no interplane struts but Fokker supposedly told him to fit them, to stop the pilots fretting. When you look at all the heavily strutted aircraft that came afterwards, I guess the concept of keeping things simple went out the window.
 

TFF

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After the Triplane came back from testing, the Army test pilots did not trust no struts. Fokker liked it without, because he like sensation. He was also the best test pilot at the company so he knew it flew fine, but a little something extra can’t hurt if it gets the sale.
 

Riggerrob

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Another version of the story claims that German General Staff ordered Fokker to add inter-plane struts to his Triplane. Since the new struts changed load paths, a few wings fell off Fokker Triplanes until Fokker perfected the struts.
We guess that Generals never looked at the massive box spars inside Fokker's wings.
 

Riggerrob

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This is why I love the internet! Instead of tapered outer wing panels lengthen the inner rib of the outer wing panel for a saw tooth and enjoy a free vortex. The 150 is the Luscombe of the new millennium. Cheap and simple.
You are suggesting a "fix" that NASA invented during the 1970s, whereas the basic Cessna 150 fuselage was a 1940s design updated with a 1950s wing. Yes, extended outer leading edges are now stock on Cirrus and Kodiak, but they took a few decades to become fashionable.
 

Dan Thomas

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Those 150 parking brakes were famous for slipping and letting the airplane roll away. No experienced pilot trusts them. They are probably made of plain 4130, with no hardening, so the sharp edges in the hole wear off and don't grab anymore. They could have been made of a plain high-carbon steel and heat-treated to harden and temper them, but then they would leave notches and raised metal on the piston shaft that would cause binding and wear in the guide. Cessna used them not so much as to save weight but to save money.

And as a mechanic, I have seen what happens to the o-rings in the master and caliper cylinders when subjected to constant pressure for days: they deform and compress and start leaking. As an instructor I told my students to use that park brake (any park brake) only to hold the airplane on a slope or in the wind while they get out and chock it, then release the brake. The brake seals in those airplanes lasted a long time.

Cessna specifies the stall warning to be set to sound at five to ten MPH (or knots) above the actual stall break. Two or three MPH is nearly useless. There's a little plastic fitting behind the slot in the wing that is supposed to seal against the inside of the leading edge, and has a nipple to attach the plastic tube to the horn. Besides often leaking at the leading edge and messing up the stall warning speeds, that plastic ages in the heat and cold and whatever UV gets at it and it cracks, or the nipple breaks off. You really don't want to know what a new one costs. A homebuilder, of course, can make his own from fiberglass, maybe.

Real pilots don't need stall warnings. They know when it will happen, and know how stall speed increases as load factors rise when maneuvering. They fly the airplane so that it doesn't stall unless they want it to. There's a real shortage of training along that line, and the accident record shows it.
 

BJC

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Besides often leaking at the leading edge and messing up the stall warning speeds, that plastic ages in the heat and cold and whatever UV gets at it and it cracks,
And that’s not the only plastic that turns to crud in a Cessna.


BJC
 

Dan Thomas

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And that’s not the only plastic that turns to crud in a Cessna.


BJC
Yup. The interior stuff degrades. Plastic wingtip and tail fairings degrade. But so does the plastic on or in any 50-year-old car that has sat outside most of the time.
 

BrianW

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Jul 2, 2018
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Location
Altus SW Oklahoma
I can assist you with simplicating the Cessna even further.

First, remove the pipe organ reed and its ducting. Donate it to the baseball stadium, or perhaps the local church, wherever pipe organs are still being used.

Then remove the doubler (if there is one) around the hole that you cut in the wing leading edge skin. (If you can, don't cut the skin in the first place)

Now, cheerfully begin to enjoy the startling performance and fuel savings that you have gained from the weight reduction, and use the cost reduction (in aircraft construction time by not having to put that entire system in place) to buy your grand-children an ice cream cone.

You may then use the stall warning system that was thoughtfully built into the 150's design - by the nice old folks who stole the Cessna 100 series design from Don Luscombe. Instead of hearing a pipe organ sound, you will feel a rumbling and shaking through the airframe as you approach a stall.
1) Mouth organ reed about 1/2 inch long
2) A seven turn spin in each direction was a requirement of my private checkout. Strange how that rumbling and shaking was completely absent in every case, so that once when I was hanging in silently (except for the mouth organ reed squealing ) my instructor kicked the rudder hard, and away we went! (Perhaps you had a Luscombe in mind? <g>)
 

BrianW

Well-Known Member
Joined
Jul 2, 2018
Messages
140
Location
Altus SW Oklahoma
Those 150 parking brakes were famous for slipping and letting the airplane roll away. No experienced pilot trusts them. They are probably made of plain 4130, with no hardening, so the sharp edges in the hole wear off and don't grab anymore. They could have been made of a plain high-carbon steel and heat-treated to harden and temper them, but then they would leave notches and raised metal on the piston shaft that would cause binding and wear in the guide. Cessna used them not so much as to save weight but to save money.

And as a mechanic, I have seen what happens to the o-rings in the master and caliper cylinders when subjected to constant pressure for days: they deform and compress and start leaking. As an instructor I told my students to use that park brake (any park brake) only to hold the airplane on a slope or in the wind while they get out and chock it, then release the brake. The brake seals in those airplanes lasted a long time.

Cessna specifies the stall warning to be set to sound at five to ten MPH (or knots) above the actual stall break. Two or three MPH is nearly useless. There's a little plastic fitting behind the slot in the wing that is supposed to seal against the inside of the leading edge, and has a nipple to attach the plastic tube to the horn. Besides often leaking at the leading edge and messing up the stall warning speeds, that plastic ages in the heat and cold and whatever UV gets at it and it cracks, or the nipple breaks off. You really don't want to know what a new one costs. A homebuilder, of course, can make his own from fiberglass, maybe.

Real pilots don't need stall warnings. They know when it will happen, and know how stall speed increases as load factors rise when maneuvering. They fly the airplane so that it doesn't stall unless they want it to. There's a real shortage of training along that line, and the accident record shows it.
I seem to have touched a nerve here. About real pilots: when you have been flying C-150s for fifty years, tell me what all real pilots know, by all means. Meanwhile, don't leave a parking brake applied for days - it's unbecoming to real pilots?
On the other hand, if you are flying a C-5 Galaxy, you will know that the brakes, all twenty-four of them slip if you apply too much power. <g>
 
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