Hair/hare brained idea begins

[Totem]

wow, that steak is gonna be rare. Well Done!

[ToyoGuy]

Wow, congratulations,  just some very nice, clean work. (and,...it works !)  Wish I could say all my stuff worked out as well all the time, but sometimes you just have to take the leap of faith and see it through for better or worse.

You know,... I would show my sweetie your / this work-log, just to prove that there's someone who thinks about this stuff more than I do,... but then I'd have to install a coach air-conditioner.

On the previously-discussed topic, sometimes I just have to stop, have a cup of joe and realize, jeeze, I've had "too much to think".

[jjrbus]

I am disappointed that no one has noticed the ice cube on the thermometer  

The weather here has only been around 90° and mostly overcast so not a fair test of my window AC.  I do not expect it to be able to maintain under 80° in the coach on a 95 degree sunny day in FL, that is what my prior testing showed. Many will think that is ridiculous, but I keep my house thermometer on 80 during the day. Any colder and I do not want to leave the house.  On the other hand it runs nice and quiet and will be great for sleeping.

                                                                                Jim

[jjrbus]

12 hours ago, ToyoGuy said:

Wow, congratulations,  just some very nice, clean work. (and,...it works !)  Wish I could say all my stuff worked out as well all the time, but sometimes you just have to take the leap of faith and see it through for better or worse.

You know,... I would show my sweetie your / this work-log, just to prove that there's someone who thinks about this stuff more than I do,... but then I'd have to install a coach air-conditioner.

On the previously-discussed topic, sometimes I just have to stop, have a cup of joe and realize, jeeze, I've had "too much to think".

It is said great minds think alike!

 

 

So do really sick ones, but let's not go there.                                 Jim

[Derek up North]

43 minutes ago, jjrbus said:

It is said great minds think alike!

 

 

So do really sick ones, but let's not go there.                                 Jim

http://thoughtcatalog.com/nico-lang/2013/09/31-famous-quotations-youve-been-getting-wrong/

[jjrbus]

The outside is done and came out and looks ok.   But I have a bone to pick with you guys.   That extension rack is too low to the ground and nobody noticed, no wonder NASA dumped you!

Too late for this trip but I will have to be super careful.     Jim   

Edited July 23, 2016 by jjrbus

[jjrbus]

2 hours ago, Derek up North said:

http://thoughtcatalog.com/nico-lang/2013/09/31-famous-quotations-youve-been-getting-wrong/

Your just upset because you missed the ice cube

[Back East Don]

19 minutes ago, jjrbus said:

no wonder NASA dumped you!

You mean the agency that is littering space with junk, loses a Mars probe due to a simple math error and has had projects fall out of orbit and crash into earth?  That agency?  I think I know why I'm not qualified.

[jjrbus]

My progress is very slow I had hoped to be on the road by the 20th of this month, this year!  The AC is up and running and most inside is done. The new inverter has arrived but that should take no more than 6 weeks to install

Reading and looking and figuring I decided on doing the genset compartment with a roofing repair tape instead of the more expensive butyl products and will be using HVAC duct board for the same cheap reason. I have come across some designs on the internet that use the Honda engine fan instead of auxiliary fans to keep the genny cool.  I am attempting to mimic those. We will see.

 

[Back East Don]

7 minutes ago, jjrbus said:

I had hoped to be on the road by the 20th of this month, this year!

I'm sure you'll get done by the 20th of some month of some year.  Hang in there.

 

[jjrbus]

I had to change direction here a bit.   There is a group of Honda fanatics that claim a quiet box needs no fan!   I am pursuing this route and ordered some Soundown foam to make better seals isolating the case of the genny from the exhaust.

I ordered the foam from Maine and was pleased it was in Orlando yesterday and in Ft Myers today.  When I looked at the shipping details it was shipped from Port Charlotte which is the next town north of me

I decided to use some THHN AWG 14 I had laying around and of course ran out.  

 

[jjrbus]

I have been monitoring how my window AC is performing and right now the remote reader seen as outdoor is sitting in the middle of the bed.  The indoor unit is sitting in the garage and showing 94° The middle of the bed in the Toy is showing 76° sitting in full sun!   I am just thrilled and hope it is not an anomaly.       Jim

[jjrbus]

I think about not posting on this as there is very little input, but there are 580 views.  Stumbling through this as best I can.   I was unable to make a good seal between case and exhaust side with duct board so ordered Soundown online for $80 delivered. 

The design has changed due to new found info so as usual things are kind of confused.  The duct board itches!  It is hard to find where people have experimented with this online, one keeps coming up where the man did great videos, but it is obvious he spent much time and effort on a fancy box that dose little to lower sound or secure his genny. Plus no one wants to give tempatures all kinds of DB levels but no temperatures of gen set running in box, $1000 gen set and they do not know what the operating temp is, makes no sense!

What does not show here is 4 hours of installing taillights and running wires an arduous task.

I am experimenting with baffle designs to lower operating temps and sound as much as practical.

I found some inspiration here.

https://picasaweb.google.com/117753292951231606905/GenBox?noredirect=1

[jjrbus]

While I have your attention, my mount for this is too close to the ground and I will have to be very careful with it.  I need some kind of simple warning device if it is going to scrape. Curb feelers or some such thing?  I believe that curb feelers depended on the sheet metal of the car to generate sound?  

[Back East Don]

44 minutes ago, jjrbus said:

While I have your attention, my mount for this is too close to the ground and I will have to be very careful with it.  I need some kind of simple warning device if it is going to scrape. Curb feelers or some such thing?  I believe that curb feelers depended on the sheet metal of the car to generate sound?  

You have thunk that I'd have more to say with regard to this project as acoustics are in my wheel house.  With regard to the last question.  The principal at work is resonance.  It is not the guitar body that generates the sound, it's the string.  The body uses resonance to amplify the sound.  So is the case with the curb feelers.  My initial thought would have been that the aluminum box would make a great sound chamber but you are going hog wild to deaden it with all sorts of baffles.  So the answer is simply, try it and see.

On to the more in depth topic of acoustics.  I presume all the effort in this is to lessen the sound?  Consider as with the case above what is generating the noise and where it is coming out from.  The case of the generator is already designed to mitigate most of the mechanical noise.  While not too familiar with the Honda, I can guess that after the exhaust, the next loudest part is from the cooling fan.  Consider a car for a moment.  They are often louder at the back than the front.  The mufflers can do a great job at keeping noise at bay or can be designed to accentuate the glorious sounds of those ponies.  Think Rolls Royce vs Ferrari.

In my work I've dealt with acoustic treatment a number of ways but principally by using sound absorption coefficients.  Those panels you bought have a list of coefficients by frequency.  These will be anywhere from .01 to 1 with one being total absorption.  This is important to understand because the lower the frequency, the harder it is to absorb. This is due to the longer wave length of low frequency.  You'll notice on a car the muffler usually does a pretty good job at idle but rev up than motor and it will make its presence known.  It is a tuned system.  Your generator and its muffler is the same thing except almost in reverse as the muffler was designed to quiet at operating speed.

So the practical ways to deal with sound are normally mass or using traps and resonators.  Sound absorption using any sort of insulation though with hot exhaust gas is worrisome.   In my work, foam treatment is often used but in comparison to rigid fiberglass insulation, it is only half as effective.  That is because it is cheaper and doesn't have the problems dealing with fiberglass has.  You have the little fibers to contend with.  Foam for sound treatment has fire retardants added but would not be suitable for an environment with hot exhaust gasses. For this application there is mineral wool or ceramic based insulation like in a furnace. 

Traps and resonators.  These are complicated to design as they work by targeting a specific frequency range or ranges through a series of baffles using the same principals of the guitar body in reverse.  This is all that a muffler is except that you have to balance the performance of the motor with the restrictions you are going to place on exhaust flow.  If you are still reading this, you might now get a sense of why I've stayed away from this topic.

From a design perspective, what part of the noise is your box addressing?

[Totem]

22 minutes ago, Back East Don said:

You have thunk that I'd have more to say with regard to this project as acoustics are in my wheel house.  With regard to the last question.  The principal at work is resonance.  It is not the guitar body that generates the sound, it's the string.  The body uses resonance to amplify the sound.  So is the case with the curb feelers.  My initial thought would have been that the aluminum box would make a great sound chamber but you are going hog wild to deaden it with all sorts of baffles.  So the answer is simply, try it and see.

On to the more in depth topic of acoustics.  I presume all the effort in this is to lessen the sound?  Consider as with the case above what is generating the noise and where it is coming out from.  The case of the generator is already designed to mitigate most of the mechanical noise.  While not too familiar with the Honda, I can guess that after the exhaust, the next loudest part is from the cooling fan.  Consider a car for a moment.  They are often louder at the back than the front.  The mufflers can do a great job at keeping noise at bay or can be designed to accentuate the glorious sounds of those ponies.  Think Rolls Royce vs Ferrari.

In my work I've dealt with acoustic treatment a number of ways but principally by using sound absorption coefficients.  Those panels you bought have a list of coefficients by frequency.  These will be anywhere from .01 to 1 with one being total absorption.  This is important to understand because the lower the frequency, the harder it is to absorb. This is due to the longer wave length of low frequency.  You'll notice on a car the muffler usually does a pretty good job at idle but rev up than motor and it will make its presence known.  It is a tuned system.  Your generator and its muffler is the same thing except almost in reverse as the muffler was designed to quiet at operating speed.

So the practical ways to deal with sound are normally mass or using traps and resonators.  Sound absorption using any sort of insulation though with hot exhaust gas is worrisome.   In my work, foam treatment is often used but in comparison to rigid fiberglass insulation, it is only half as effective.  That is because it is cheaper and doesn't have the problems dealing with fiberglass has.  You have the little fibers to contend with.  Foam for sound treatment has fire retardants added but would not be suitable for an environment with hot exhaust gasses. For this application there is mineral wool or ceramic based insulation like in a furnace. 

Traps and resonators.  These are complicated to design as they work by targeting a specific frequency range or ranges through a series of baffles using the same principals of the guitar body in reverse.  This is all that a muffler is except that you have to balance the performance of the motor with the restrictions you are going to place on exhaust flow.  If you are still reading this, you might now get a sense of why I've stayed away from this topic.

From a design perspective, what part of the noise is your box addressing?

Careful... don't get called a nay-saying troll. Lets see what happens with this experiment

We all know the more you tell him its not a great idea the more complicated he will make it...

 

[Back East Don]

1 minute ago, Totem said:

Careful... don't get called a nay-saying troll. Lets see what happens with this experiment

We all know the more you tell him its not a great idea the more complicated he will make it...

 

I made no comment on the idea of this.  I highlighted the challenges and asked a couple important questions.  If that makes me a troll, so be it.

[Back East Don]

For anyone who would like to view an powerful demonstration of resonance. This is a short youtube video of the Tacoma Narrows bridge collapse.

The designers didn't take resonance into account and the results were a spectacular failure because hey, math is hard.  So for anyone keeping score, this is how you troll.

 

 

[jjrbus]

This is something I have wanted to play with for some time.   I have seen other people pull it off very successfully and  I have done it one time before with a Honda EV4010.   I am not happy with the Duct board but have to keep cost down so cannot hope for silence.

The motor side of the Honda should generate less noise so I will use the Duct board there, I will the use the pricey Soundown on the exhaust side where most of the noise is.  I am experimenting with routing and baffles and think I have found an issue with what is being reported on the net.  They are reporting air temp in the engine side slightly higher than ambient, I have been measureing case temp.  If I put remote thermometer in air stream instead of on case temp drops from 110 to 92 with 92 ambient temp.

So I will continue to experiment with this, I may end up with an expensive storage compartment for the gen set?

I have been looking and thinking and wondering about attaching a tomato paste can to the bottom of the steel rack as a noise maker?     Jim

I remember watching the Narrows bridge video.

 

Edited August 2, 2016 by jjrbus

[WME]

Wow got a head ache just reading that missive 

I think we're dealing with 2 noises, one needs to be amplified (curb feeler) the other needs to be dampened (genset).

I think a 1/2' wide piece thin spring steel sticking down about 1" and bolted to the rack would make a nice screech if it rubbed on something

I've had good results using acoustic mass damping with a lead/foam matrix for sound reduction. Of course is the humble opinion of a guy who once stapled a 1,000 card board egg cartons to some walls to make a dead end for a stereo demo room, Bose 901s didn't like this very much

 

 

[Back East Don]

6 hours ago, jjrbus said:

I am experimenting with baffle designs to lower operating temps and sound as much as practical.

I found some inspiration here.

I want to note that in the pictures you linked to the white insulation used is a refractory type.  Important point because the exhaust exit is really hot.  He also uses a two chamber baffle for the exhaust with bottom exit at the end.  Both the baffle and the insulation is working to reduce the sound level.  I also suspect the foil faced insulation is mineral wool.  Would be a good choice as mineral wool is good to 1200 degrees and the ceramic stuff he used 2500 degrees.  Both will also have good NRC ratings (noise reduction coefficient).

[Back East Don]

22 minutes ago, WME said:

Wow got a head ache just reading that missive 

I think we're dealing with 2 noises, one needs to be amplified (curb feeler) the other needs to be dampened (genset).

I think a 1/2' wide piece thin spring steel sticking down about 1" and bolted to the rack would make a nice screech if it rubbed on something

I've had good results using acoustic mass damping with a lead/foam matrix for sound reduction. Of course is the humble opinion of a guy who once stapled a 1,000 card board egg cartons to some walls to make a dead end for a stereo demo room, Bose 901s didn't like this very much

 

 

Can you imagine writing it.  Sorry, I did the best I could keeping the explanations at the ground level but the practicalities of acoustics are just complex. 

Like the Tacoma Narrows bridge, people don't factor in the environment.  This is true with things like this isolation chamber or a listening or live presentation space.  The lead foam combo is certainly a better choice at making a dead end than those egg cartons.  You might gets some limited mid diffusion with the egg cartons but very little broadband absorption.  Here in lies a point that is often misunderstood.  There is a world of difference between sound treatment and soundproofing.

In the picture Jim linked to, there is insulation inches from the exhaust exit.  Here foam would be a fire hazard.  In fact I would contend that around this gas powered device, I would keep combustibles to a minimum. 

[WME]

5 hours ago, Back East Don said:

.  You might gets some limited mid diffusion with the egg cartons but very little broadband absorption.  Here in lies a point that is often misunderstood.  There is a world of difference between sound treatment and soundproofing.

In the picture Jim linked to, there is insulation inches from the exhaust exit.  Here foam would be a fire hazard.  In fact I would contend that around this gas powered device, I would keep combustibles to a minimum. 

So where was the wise elder when I was stapling things?

This might help with heat, https://www.summitracing.com/parts/dei-010131/overview/

Edited August 3, 2016 by WME

[Totem]

if this catches on fire and burns up that expensive toy and generator along with all of that  extra $ fixins, my $1000 HF generator and mach 1 PS combo will be looking pretty sexy; in fact right now its too sexy to even describe on a family friendly website...

my anti-theft device is simple... a ratchet strap on the bumper and I just used mine while driving through 99 degrees of southern states while on holiday.

But I gotta admit, that stanless steel box looks sweet. I would have used it too had I had one, only mine would be full of extra gear not  all that baffling trying to make the super quiet honda even more quiet. When done I am expecting this thing to go unheard at a Helen Keller rally.

[Back East Don]

22 minutes ago, WME said:

So was the wise elder when I was stapling things?

Probably in the recording studio.  Built my first one in the 70's

At Home

At Work

On the road

[Back East Don]

Quick note for Jim with regard to the foil faced insulation.  The foil part of mineral wool would not be needed and would be acoustically reflective of higher frequencies.

Something like this would do Home Depot Mineral Wool

Cheap and effective plus will have no issue with the high temp.

[jjrbus]

Too late on material, I will be using what I have, but many thanks.

As I researched this I found some odd things, things that don't set right.  One of the links shows a gen set in a wooded box. There are many of them and my original sound box for a Honda was made of plywood lined with a foam made for that purpose. Many of the sound boxes for the Honda are made from plastic containers.

When ToyoGuy posted a pic in response to my plea for case temperature the highest temp he recorded was 182° I have recorded a high of 190°, Hardly a need for exotic high temp material. I am not sure of the exhaust temp itself, I have no way of accurately measuring it.

A spring for noise, great idea.  I used to have no problem finding odds and ends such as that, now not so easy.         Jim

 

 

[jjrbus]

Honda in plastic storage container.        https://photos.google.com/share/AF1QipMJVLWWtKSE6ZtE66u6-FFU7H4wgDoehpOyzTQLXpSCtckz6Z5Q-Nq38Gw2Y9OfIA?key=UDRlUFNlQXEwaGZfbTBTQ21HYS0xYmdpR3U2TmNB

[jjrbus]

On 8/2/2016 at 2:03 PM, WME said:

Wow got a head ache just reading that missive 

I think we're dealing with 2 noises, one needs to be amplified (curb feeler) the other needs to be dampened (genset).

I think a 1/2' wide piece thin spring steel sticking down about 1" and bolted to the rack would make a nice screech if it rubbed on something

I've had good results using acoustic mass damping with a lead/foam matrix for sound reduction. Of course is the humble opinion of a guy who once stapled a 1,000 card board egg cartons to some walls to make a dead end for a stereo demo room, Bose 901s didn't like this very much

 

 

Not having any luck on finding spring steel, any suggestions?     

[Back East Don]

18 minutes ago, jjrbus said:

Not having any luck on finding spring steel, any suggestions?     

What is wrong with your original idea of curb feelers?

[WME]

Curb feelers work. Anything with a coil spring inside old seat belt reels, retractable dog leashes, look in junk piles. Make a small bolt on clamp so that you replace the screecher when it wears. Piano wire would work too.

If only the best will do http://www.mcmaster.com/#standard-spring-steel-sheets/=13l244j

Edited August 5, 2016 by WME

[jjrbus]

I suspect but don't know that curb feelers need a ????   thin metal such as a fender to make noise. 

[Back East Don]

11 minutes ago, jjrbus said:

I suspect but don't know that curb feelers need a ????   thin metal such as a fender to make noise. 

So mount them to a ????

I'll avoid the long explanations so WME's head doesn't explode.  You have the metal frame that is connected to the frame or the RV which is connected to the body of the RV which is connected to the cab of the RV.  Following along?  If your nice new frame and box start scraping the ground, I'm pretty sure it is going to make a bunch of noise and it is also connected to ????

[jjrbus]

8 minutes ago, Back East Don said:

So mount them to a ????

I'll avoid the long explanations so WME's head doesn't explode.  You have the metal frame that is connected to the frame or the RV which is connected to the body of the RV which is connected to the cab of the RV.  Following along?  If your nice new frame and box start scraping the ground, I'm pretty sure it is going to make a bunch of noise and it is also connected to ????

I suspect but don't know that a curb feeler dragged on the ground will not make much of a noise without something to amplify it, such as a fender?

[Back East Don]

4 hours ago, jjrbus said:

I suspect but don't know that a curb feeler dragged on the ground will not make much of a noise without something to amplify it, such as a fender?

And how would a piece of spring steel be different?  Same principal.