AIRPLANES--Things I have always questioned

Giles

(1)--Why do airplanes not have muffler to cut sound?
(2)--Many things are dropped from airplanes using parachutes, race cars and even the space shuttle use parachutes to slow them down.
Why do airplanes not have parachutes attached to their fuselage to slow the decent when a crash is imminent?

Scuba_Dave

Look at the size of this parachute compared to this lightweight plane
Do the math

Tom Struble

a muffler on a jet?

sdsester

Sucking in a bird is natural jet engine muffler. I don't understand why they are always firing off cannons to scare the things away.

The question I am asking is now that personal jets are just around the corner and some are already mapping out airports? Will texting and talking on cellphones be allowed in the air? Will there be legal limits to establish FUI? Will women fard (to apply makeup) in personal jets like they do in cars on the expressway?

I see jet fuel cleanup and roof replacement businesses being hot in the near future. I cannot wait for Illinois drivers to be airborne in their own jets! LaLanders too of course. NYC drivers and even those in Philly never bothered me so much. Chicago drivers don't either but wow was Champaign Urbana an experience is psychotic motorist behavior.

brons2

Personal jets are not around the corner. A "personal" jet like the Eclipse 500 still costs approximately $1.5mil list. And the ACMI cost of a small 6 place jet like the Eclipse is probably north of $200 per hour.

If anything makes flying more accessible, it will be the new light-sport category. Jets will remain in the domain of the multi-millionaire for now.

As to the OP,
1) it would cut airflow too much, thereby reducing efficiency. Powerplant engineers attempt to reduce noise through different ducting designs, and washing bypass flow over core flow. The new 787's have chevrons on the engines that supposedly reduce noise.
2) some smaller planes do have parachutes, for example the Cirrus SR-22. It would take too big of a parachute for a big jet though, again reducing efficiency. The public is not willing to pay triple or quadruple price for tickets on a parachute equipped commercial jetliner. Not to mention that, the most dangerous phase of flight is takeoff and landing, and during those phases the parachute would be of dubious benefit as it probably would not have enough time to deploy successfully.

JetAviator7

The truth is, airplanes DO have mufflers, even jet engines. Without them there would be a great deal more noise.

With respect to parachutes, a number of light airplanes have them, and they have had some success. One of the problems is that even though the chute will slow down the descent, you have no control over where the aircraft will land, and therefore some injuries have occurred.

The comment about why fire cannons to chase of birds has to do with the fact that birds cause millions of dollars of damage to aircraft, and in some cases bring aircraft down or kill pilots.

JetAviator7

John M. White, Publisher

nap

So, can I run down to Autozone and pick up a muffler for my 737?

nap

you need to realize that the race cars and the space shuttle chutes are to slow them down in addition to any other means of braking on the vehicle themselves. The braking chutes are supplemental to the mechanical brakes as the chute itself would not be effective enough to stop the vehicle within anything close to a reasonable distance without the other braking systems being used.

unless you have "air brakes", a comparably sized chute would do very little to increase survivability.

think about how large of a canopy is used for just one man just to slow him down enough so he is not broken on landing. Even then, if you land improperly, you can still get severely injured.

Consider the average guy, oh, say, 180 lbs. a boeing 737-800 has a max take off weight of 155,500 lbs. That is about 864 times the weight. I am not into physics but a bit of logic would tell you the canopy needed would be fricken huge and then, it has weight as well so you reduce the capacity of the plane as much as the chute systems weighs.

Now, if you started figuring out how low the percentage of flights end in a crash, you would quickly come to the conclusion, even if you could install a chute in a reasonable fashion, would be quite expensive compared to any gains.

Tom Struble

fricken huge?is that metric nap?

nap

yes. If I used the English equivalent, I think I would get banned

tpolk

hows about some parachutes on that blue ice huh huh

__________________
The older I get the better I was

norvet

Every piston engine airplane I have ever seen have no muffler. I just came in from my yard and observed six small planes and every one was real loud. Is it a safety reason that the exhaust is emitted without being muffled? My son has had two Cessnas and now has Beachcraft Baron and none of these had any mufflers on them. Anyone know the reason why?

nap

mufflers generally cause a loss of power, add weight, and take up precious space.



but even given that, here is a page where you can buy mufflers for some planes, including some Cessnas.

norvet

Thanks for the info. I live near the beach and in we have airplanes towing message signs almost all summer and the noise gets old after a while, a steady drone all day long. I've tried to contact the FAA, but they would not give me an answer...................

nap

you want noisy piston engine planes?

listen to a P51 or a Jap zero. they are loud, especially when climbing fast.


I would think for something like the banner planes they would have to abide by local noise ordinances or possibly a nuisance issue ordinance.