[REPORTED] Flaps Down Warning sound

[Crumpp]

It doesn't change the fact that nothing in these manuals indicates that the horn went silent if the engine wasn't in idle. On the contrary, it clearly states that the horn was hard to hear if the engine wasn't running idle.

 

Correct translation:

The horn can only be heard clearly if the engine is running idle.

 

Again, it is written for the pilot not the mechanic.

 

It is fact the sentence does not say the horn runs continuously. :thumbup:

 

Hearing it clearly at idle is not "horn sounds continuously".

 

It works just like every other gear warning horn and comes on when the flaps are down and power is reduced.

 

From a mechanics standpoint....that makes sense.

[Crumpp]

The emphasis on the part that it is "only" heared "well" when at idle implies that it can be heared also if not at idle - just not as good as otherwise.

 

You are right, it does not mean that it will sound at every throttle setting, but at least it is not limited to only idle.

 

I wouldn't think it just worked at idle. Most aircraft require some power to maintain Vref on a ~3 degree glide slope in landing configuration. Most horns will go off if the throttle is reduced to the vicinity of that power setting,

[Derbysieger]

Assuming, just from a users standpoint, I read this manual and then got into the aircraft and flew. The way it is worded I would expect this horn to be on as soon as I lower flaps with the gear up or in a transitional state. I may not be able to hear it well if the throttle isn't idle but I would expect it to be on.

 

Now, it doesn't clearly say that it's on all the time, but it is worded in a way that I, as a native speaker, would expect it to be on as soon as both the conditions that are given in the manual are met, regardless of throttle setting.

 

To be 100% certain we'd have to look at a plan of the actual wiring but that's what I would take from the manual.

[Crumpp]

 

 

That is all. Maybe the horn stopped at a higher power setting but I heven't found anything in the manuals to indicate this.

 

My suggestion would be to Look in the maintenance manual for the mechanics not the pilots manual if you want a detailed technical description of how the gear horn works.

[Derbysieger]

Maybe there's something specific in here:

 

http://www.avia-it.com/act/profili_daerei/libretti_velivolo/PA_libretti_tedeschi_PDF/Bf-109K-4.pdf

 

I'll have a look tomorrow.

[Crumpp]

Assuming, just from a users standpoint, I read this manual and then got into the aircraft and flew. The way it is worded I would expect this horn to be on as soon as I lower flaps with the gear up or in a transitional state. I may not be able to hear it well if the throttle isn't idle but I would expect it to be on.

 

Now, it doesn't clearly say that it's on all the time, but it is worded in a way that I, as a native speaker, would expect it to be on as soon as both the conditions that are given in the manual are met, regardless of throttle setting.

 

To be 100% certain we'd have to look at a plan of the actual wiring but that's what I would take from the manual.

 

I think it is unlikely it sounded all the time. If it did I am sure most Bf109 gear warning horns either did not work or were replaced often.

[Derbysieger]

All the time the conditions were met. The horn would only sound in the time between retracting the gear and raising flaps just after take off and also if you lower flaps for landing before lowering the landing gear or if the gear isn't locked.

 

8. Signalhorn ertönt, wenn das Fahrwerk nicht mehr eingerastet ist und gleichzeitig die Landeklappen angestellt sind.

Das Horn ist nur bei Leerlauf gut zu hören.

That quote is from the part of the manual describing a normal take off with 20° flaps, not landing which makes me lean even more towards the assumption that it has nothing to do with the throttle setting.

 

 

Using flaps in combat in the Bf 109 seems highly unpractical due to the amount of time it takes to lower and raise them so that shouldn't be a factor.

Edited March 24, 2015 by Derbysieger

[I.ZG15_FALKE]

I think it is unlikely it sounded all the time. If it did I am sure most Bf109 gear warning horns either did not work or were replaced often.

 

What do we know from the sources?

Two conditions lead to a sounding horn

a) retracted gear

b) deflected flap

We have an additional information that the sound is heard clearly if the engine is in idle.

That's what good sources say.

 

You may think and assume what you like, if you want to proof that the sound is only if engine is in idle, just come up with some proof, not assumption and guess.

 

Btw no German native speaker would understand that sentence in a way that the horn is only sounding while the engine is in idle. There is a clear difference between sounding and being audible.

[messermeister]

Signal horn was dropped from production in early 1944, so no horn for K-4:

 

[Crumpp]

What do we know from the sources?

Two conditions lead to a sounding horn

a) retracted gear

b) deflected flap

We have an additional information that the sound is heard clearly if the engine is in idle.

That's what good sources say.

 

You may think and assume what you like, if you want to proof that the sound is only if engine is in idle, just come up with some proof, not assumption and guess.

 

Btw no German native speaker would understand that sentence in a way that the horn is only sounding while the engine is in idle. There is a clear difference between sounding and being audible.

 

You are making as much of an assumption and guess as I am Falke. The only difference is one fits the purpose of a gear warning horn and the way in which they function in aviation.

Edited March 24, 2015 by Crumpp

[Crumpp]

Signal horn was dropped from production in early 1944, so no horn for K-4:

 

 

Excellent find. Our Bf109k should not have a horn at all then.

[Hummingbird]

Makes little sense if it sounded every time you touched the flaps as well, considering that many 109 pilots mention using flaps in hard maneuvers much of the time. The hand wheel also makes it easy to apply minute amounts of flaps for the incremental increase in CL_max that you might need in a fight without crossing that line of causing too much drag and/or reducing the critical AoA too much.

[NineLine]

Makes little sense if it sounded every time you touched the flaps as well, considering that many 109 pilots mention using flaps in hard maneuvers much of the time. The hand wheel also makes it easy to apply minute amounts of flaps for the incremental increase in CL_max that you might need in a fight without crossing that line of causing too much drag and/or reducing the critical AoA too much.

 

 

Of course that also might explain why it was removed in early 1944 as well if it did fire every time you touched the flaps.

[Solty]

You are making as much of an assumption and guess as I am Falke. The only difference is one fits the purpose of a gear warning horn and the way in which they function in aviation.

 

Umm no.

1. He is German

2. He is a translator.

[NineLine]

You are making as much of an assumption and guess as I am Falke. The only difference is one fits the purpose of a gear warning horn and the way in which they function in aviation.

 

Its a tough call here, for the translation I am going to lean towards what Falke said BUT if you have any wiring diagrams for similar systems, preferably German showing how they worked, that could sway it the other way as well.

[Yo-Yo]

Excellent find. Our Bf109k should not have a horn at all then.

 

It is not so doubtless because this document is for G model. Reworked wiring diagram for K4 contains this horn and all circuit. Logically, all changes that were made for earlier model with special lists and add-ons must be included in the subsequent design.

[NineLine]

It is not so doubtless because this document is for G model. Reworked wiring diagram for K4 contains this horn and all circuit. Logically, all changes that were made for earlier model with special lists and add-ons must be included in the subsequent design.

 

So if you have the wire diagrams, am I to believe that the horn is working as those diagrams state and perhaps all we need is an adjustment of the volume so it blends into the engine noise more at higher RPMs?

[iFoxRomeo]

Excellent find. Our Bf109k should not have a horn at all then.

That is no evidence for the K not having a signalhorn. Only the maintenance manual of the K can clear this point.

 

Makes little sense if it sounded every time you touched the flaps as well, considering that many 109 pilots mention using flaps in hard maneuvers much of the time. The hand wheel also makes it easy to apply minute amounts of flaps for the incremental increase in CL_max that you might need in a fight without crossing that line of causing too much drag and/or reducing the critical AoA too much.

 

How does a signalhorn prevent the pilot from using the flaps in hard maneuvers?

I guess they didn´t idle the engine during hard maneuvers.

And I couldn´t care less about the signalhorn if I tell someone my war stories.

Because no 109 pilot mentioned the signalhorn, it does not mean it wasn´t there.

 

 

Fox

[I.ZG15_FALKE]

You are making as much of an assumption and guess as I am Falke. The only difference is one fits the purpose of a gear warning horn and the way in which they function in aviation.

 

No need to get crumpy:smilewink:

 

What we dicussed is a G Series document as a source

which - from the newer finds - should anyway be in doubt if we could use it.

 

In this source only two facts were mentioned, a third was added through your educated guess. It doesn´t make sense to discuss this without having a clear source. Yo-yo seems to have good documentation on the system in a K series. Therefore I have no doubt it will either already be working correctly or it will be changed to work correctly.

 

Jeez all of us are nitpickers when it comes down to getting things as correct as possible.

 

So let´s have a [good old german] beer together some time ...

Edited March 24, 2015 by I./ZG15_FALKE

[Yo-Yo]

So if you have the wire diagrams, am I to believe that the horn is working as those diagrams state and perhaps all we need is an adjustment of the volume so it blends into the engine noise more at higher RPMs?

 

I think so.

[Crumpp]

No need to get crumpy

 

No need to get your beak bent, Falke. :smilewink:

 

a third was added through your educated guess.

 

Well, a gear warning system does not function as a gear warning system unless it tells the pilot in landing configuration that the gear are not down.

 

That is why 14 CFR 23.729 - Landing gear extension and retraction system is written the way it is with two requirements for any basic gear warning system.

 

(f) Landing gear warning. For landplanes, the following aural or equally effective landing gear warning devices must be provided:

(1) A device that functions continuously when one or more throttles are closed beyond the power settings normally used for landing approach if the landing gear is not fully extended and locked. A throttle stop may not be used in place of an aural device. If there is a manual shutoff for the warning device prescribed in this paragraph, the warning system must be designed so that when the warning has been suspended after one or more throttles are closed, subsequent retardation of any throttle to, or beyond, the position for normal landing approach will activate the warning device.

(2) A device that functions continuously when the wing flaps are extended beyond the maximum approach flap position, using a normal landing procedure, if the landing gear is not fully extended and locked. There may not be a manual shutoff for this warning device. The flap position sensing unit may be installed at any suitable location. The system for this device may use any part of the system (including the aural warning device) for the device required in paragraph (f)(1) of this section.

 

A case could be made that the Bf-109 fulfills requirement number one by a "calibrated" volume that can only be heard when the power is reduced. If so, that is not the most elegant solution. That point would have considerable variation and would mean power was applied to the horn for much longer than necessary. You would be replacing horns much more often if it works that way. It is just too easy to put a switch on the airspeed or throttle to complete the warning horns circuit so that it works at a precise point. That is what most aircraft do.

 

So let´s have a [good old german] beer together some time ...

 

Always in the mood for some good German Beer!!

[Anatoli-Kagari9]

Couldn't the logic simply be to "alert" the pilot for the fact that flaps were deployed, and gear up, no matter in what phase of flight?

 

If getting ready for landing, it would avoid ditching, if in the heat of the combat, used during tight turns, it would alert the pilot for the need to clean the aircraft again when possible ...

[iFoxRomeo]

No need to get your beak bent, Falke. :smilewink:

 

 

 

Well, a gear warning system does not function as a gear warning system unless it tells the pilot in landing configuration that the gear are not down.

 

That is why 14 CFR 23.729 - Landing gear extension and retraction system is written the way it is with two requirements for any basic gear warning system.

 

 

 

A case could be made that the Bf-109 fulfills requirement number one by a "calibrated" volume that can only be heard when the power is reduced. If so, that is not the most elegant solution. That point would have considerable variation and would mean power was applied to the horn for much longer than necessary. You would be replacing horns much more often if it works that way. It is just too easy to put a switch on the airspeed or throttle to complete the warning horns circuit so that it works at a precise point. That is what most aircraft do.

 

 

 

Always in the mood for some good German Beer!!

Why would Messerschmitt care about 14 CFR 23.729?

Was this ordered by the german government back then?

 

 

Couldn't the logic simply be to "alert" the pilot for the fact that flaps were deployed, and gear up, no matter in what phase of flight?

 

If getting ready for landing, it would avoid ditching, if in the heat of the combat, used during tight turns, it would alert the pilot for the need to clean the aircraft again when possible ...

 

I´d say this is the logic behind that.

 

 

 

 

Even if pilots used the flaps during combat, this doesn´t necessarily mean it was intended by Messerschmitt to use the flaps during combat.

 

Fox

[Solty]

No need to get your beak bent, Falke. :smilewink:

 

 

 

Well, a gear warning system does not function as a gear warning system unless it tells the pilot in landing configuration that the gear are not down.

 

That is why 14 CFR 23.729 - Landing gear extension and retraction system is written the way it is with two requirements for any basic gear warning system.

 

 

 

A case could be made that the Bf-109 fulfills requirement number one by a "calibrated" volume that can only be heard when the power is reduced. If so, that is not the most elegant solution. That point would have considerable variation and would mean power was applied to the horn for much longer than necessary. You would be replacing horns much more often if it works that way. It is just too easy to put a switch on the airspeed or throttle to complete the warning horns circuit so that it works at a precise point. That is what most aircraft do.

 

 

 

Always in the mood for some good German Beer!!

So you want to apply modern standards (from 1999?) to a plane that was made in 1944 and the system was present probably even in 1938...ok

[Crumpp]

So you want to apply modern standards (from 1999?) to a plane that was made in 1944 and the system was present probably even in 1938...ok

 

Well with a little historical knowledge of Aviation Law and Convention...it makes much more sense Solty.

 

Why would Messerschmitt care about 14 CFR 23.729?

 

Obviously Mtt would not care about a modern FAA regulation. However, all of these regulations are part of international convention and mirror each other. The agreement of having universal airworthiness standards goes back to 1919.

 

Germany was not only a signatory of convention, she was a major contributor in terms of engineering airworthiness standards for aircraft.

 

Seeing something that does not conform, especially in the area of subsonic piston engine designs which have changed very little since World War II....should be cause for further investigation.

 

Was this ordered by the german government back then?

 

Yes, there will be something similar in the RLM.

Edited March 25, 2015 by Crumpp