Discseven............

YOU SIR ARE A STEELY EYED MISSILE MAN - :cool:

RonO... knowing you to be an engineer of measurable repute, am always interested in your perspectives & input. Gather you're thinking of a sucker concept (not like that :eek:) with fan on air-exit side of condenser. If you would, sketch what you have in mind and post it. I looked at a sucker idea but there were obstacles in my view. You may see it from a completely different---and doable---perspective.

Yes on blow-through. Original idea was indeed to put turbine as far from cabin as possible---engine and turbine noise would likely have blended rendering turbine moot. That positioning doesn't work because ducting arcs where turbine was intended to be. And so the move forward. Length of duct is based on drawing air in from as far from engine as possible and from as near to exterior air as possible. And so the idea of intake being ahead of wheel and close to rocker level.

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Gona help you with suspension (if you need) when AC is done---will surly be before end of 2018.

Intake stack progress

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Intake stack’s bend insulation. This is outer layer = closed cell foam. Stuff cuts much easier than fibered insul. Pattern is not symmetrical due to subtle turn (towards inside of car) as duct also bends with axis of car.


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Left side is vertical stack---filter inside. Top right is turbine’s house. This is total section that will come out of car to service turbine/motor. 1 quick-release strap holds stack to car---will be center strap of 3 straps seen here on vertical section. 2nd retainer strap is a “loosen-only”... is positioned aft of turbine’s house. At this moment, am sorting how to config insulation around turbine housing for easy access to blades & brushless motor. (CG commented earlier in thread on supercharger run without filter showing results to blades. Is motivation in this case to eventually check blades to see what happens with 1/8” mesh filter given my driving environment. Another unknown = how unsealed brushless motor will hold up.) Point here is it being one thing to set parts in place... another to take them apart. Am attempting to think in both directions.


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Joint between turbine-house and bend leading down to intake. Idea is to lap insulation. Closed-cell foam insul has peel-and-stick backing. Decided not to use it. If downstream mod is needed, "floating" insul will simplify things.


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Another fitting in progress. This is to get more accurate read on CEET's required length, push-fit into crevice (above wheel), and look at mounting bracket's positioning. In final form, CEET duct will be insulated. Plan is foam insul only. Turbine noise control may alter this plan---more insul may be needed. Joining CEET duct directly to turbine's house was tested. Even with turbine's house skinned, getting CEET onto house was not consistently a simple matter---even a little fumbling is justification to wonder WTF! There’s now a hard-female coupling permanently attached to CEET's forward end. This config adds 2 clamps but fumbling is no more.


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CEET directly above wheel. Duct is distorted into an oval form in this area. This flattens duct some---increasing clearance between it and tire---and allows it to be shoved into crevice just above rear lid release cable’s sheath. Credit to Raff for suggesting aviation duct material and RawKnucklesRonO for source---turns out this is excellent conduit in this area due to its' flexibility & rigidity combo. Imagine an arch wanting to straighten out on it's pivot point… then add a little compression to it’s elastic length. Next, stuff arch it into crevice with a friction fit. If you see dynamics of this like I do, you'll recognize how nicely aviation duct performs here. Is great pleasure doing P-car projects... moreso with input/ideas like this---thanks guys! Bottom line, I believe dynamics here means CEET duct needs no attachment to car. Only for security purposes am I going to zip tie it to cable's sheath (locations arrowed).


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Intake stack's connection to car has seen a number of iterations come & go. This version is on its way out. Could make molded fender to fit void here but something’s not right with mounting config. Not sure what it is yet but gut’s call is clear enough to push eject button on this. Will rethink what's happening here.


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Clearance between tire & duct (overhead) was “calculated” early-on to establish feasibility for direction taken. Knowing calculations can be ball-crushers on occasion… am now---albeit later than sooner---checking clearance to be sure there's adequate space. This 911 has 23 1/8" ground-to-rear-fender measure... static clearance between tire & overhead CEET duct = 4". With tight suspension, survivability of this duct has high probability. No baja.

12v motorcycle batt is in. If day goes according to plan, will connect electronics later in day for first stab at Arduino autonomy.

Arduino Sketch/Program

ESC is arming and operating brushless motor correctly with this sketch. For the moment, have turbine at half speed---noise level seems doable. Tested full speed... :eek:. Letting system run a few hours... checking motor & ESC temps along the way.

__________________

#include Servo.h // should be pointed brackets around "Servo.h" pointing away at both sides---Forum text format does not recognize those brackets. This calls "Servo.h" in from Arduino library

Servo myservo; // "myservo" is name given to servo

void arm() // setting up arming protocol specific to Turnigy Plush 40a ESC
{
myservo.write(0); // zero speed arms ESC
delay(1000); // 1 second delay required
}

void setup() // setting up connection assignment and speed declarations
{
myservo.attach(9); // pin 9 is signal wire connected to ESC
arm(); // arming protocol called in
for (int speed = 0; speed <= 90; speed += 5) // speed is initially 0 and goes up to half speed as measured in degrees---180 degrees is full speed, speed sweeps up to half speed in 5 degree increments
{
myservo.write(speed); //calling in speed protocol
delay(1000); // sweep up proceeds in 1 second intervals, can increase interval but not decrease from 1000ms
}
}

void loop() // nothing loops
{
}

KinkyK, no sketch, or even a "though out" idea from me . . . was just hit with the thought at the time that it seemed like placing the motor as close to the condenser bucket, perhaps at its exhaust (suck :eek: though style) side, might simplify things (mainly your piping arrangement).

Definitely major, space limitations, though (like you mentioned).

Really good idea about placing the air intake pick-up point as far away from the engine exhaust as possible - nice!

Glad to have given you a heads (:eek:) up about the aircraft ducting - always happy to help you spend money! :D

^^^ Chit RonO... was eager to see what your perve-mind was conceiving here! That's a let down Bro. Was not foolin around when suggesting you seeing things differently and with more finesse than I. Am always open to your input.

TY on intake. (Bong-days referenced.)

YOU spending MY money... no worries--is all on goodstuff :D

Was no overheat of brushless motor or ESC in yesterday’s multi-hour run. Am getting on with loading turbine-house into duct-house.


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Footers---that served bench testing---they're now in the way. They’ll be removed.


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Turbine house is taken apart to blue-Loc all machine screws. Regarding vibration, turbine/brushless motor balance (in this case) is such that were you blind folded, unable to hear unit running, and were it not tugging due to moving air, you could hold turbine’s housing in hand when it’s running---at any speed---and not realize it’s running. Sensation is like… holding an electric unit in hand and sensing current flowing.


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Fender compression’s working well---is snug fit without requiring nasty-force to insert unit. Alternative to this house-in-house config was considered... Idea was to use reduction coupling on intake side and same coupling flipped around on exhaust side. Couplings found were rubber. Way turbine housing is made---with plastic at both ends---connecting rubber couplings to this plastic was not appealing. Can remove plastic ends on turbine-house but then there’s not much house-measure remaining to work with. Rubber couplings were also concerningly flimsy (for using in this particular app.) For sake of entire duct’s stability, house-in-house path was chosen.


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Bullet junctions disconnecting in this environment seems very unlikely. Because strange things happen, they’re getting locked.


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Stainless wood screw driven into each fender.

Next... going to connect all parts as they are---without further insulation being applied---to check noise and air flow. Am ubercurious to see if duct will convert into unforgiving didgeridoo.

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Bench’ing system with 12v 7.0 ah sealed motorcycle batt. ($14 direct from maker.)


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Arduino powers up with 5v from ESC via BEC cable. (ESC is connected to 12v battery here.) Sketch is automatically run by Arduino (on power up) with arming signal sent back to ESC (white wire)… followed by protocol for brushless motor to run. ESC has 3 pulse wires connected to brushless. System works given forked power wire at compressor... one fork leading to ESC. When compressor is ON… so is ESC>Arduino>brushless motor.


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System bench test

Roughly configured (without planned insulation installed yet and bend in flex-duct estimated) am checking air volume exiting condenser and noise level. First speed check is @ 50% (of full speed.) Turbine noise level---even without insulation around turbine area---is inconsequential. Slight high pitch whine is heard at intake with ear at intake. Majority of noise is wooshing of air resonating from air-bucket and out through condenser fins. Insulation on air-bucket---insul being primarily to maintain temp delta between air in bucket and air outside bucket---is likely going to offer some dampening of bucket resonance. Installed, exhaust from condenser faces engine… more dampening is assumed.

Second speed run is @ 60%. Whine at intake and wooshing at tail-end has of course increased. Thinking about test environment factors now… there’s zero ambient noise but for system running i.e., there’s no engine running, no tire/road contact, no traffic or other surrounding noise. Also, am not in cabin with window closed hearing noise from evap blower and air passing through ducts to cab. We're also in Targaland as opposed to coupeee. Bring all that acoustobabble to bear... 70% speed seems feasible. 80%... doubt that has wings.

Air flow…

Without deflector installed inside air-bucket, air flow is extremely uneven exiting condenser. (Final deflector form will not insert through inlet to bucket. Must wait until bucket is removed to correct condenser ports---deflector connects to bucket then.) Regardless, air volume coming through condenser is good.

Maybe some Dynamat stuck on the body of the car before the duct-work is put in place would help silence any of the racket into the cabin.

Another fine idea... TY Glen! In regard to racket, just tested higher speeds. Above 60% speed, turbine/brushless whine is omni-present and annoying. Whether that frequency would penetrate tub... unknown. Combo duct-car insulation program has potential. Will bury contraption in blankets tomorrow to see what affect insulating further has.

Do you have first-hand experience with Dynamat?

Dynamat (CLD) will reduce the resonance of floppy metal panels, which makes the vibrations and noise emitted from said vibrations easier to control. It will block sound to a small degree, simply due to its mass, but mass-loaded vinyl (MLV) is more efficient in this regard. As MLV is not directly adherent in the way that CLD panels are, it would be more difficult to affix to the exterior of the car (it would usually go in the interior behind the seatbelt panel for this application).

I would wait to see if your goals are achieved with the system in place before worrying too much about quieting it down.

On your concern about the downward facing intake becoming a water vacuum in the case of standing water, couldn't you fit a CIS style pop-off valve facing inwards before the motor? If water covers the end of the intake there would be a strong vacuum as it tried to suck up the water. Valve then pops inwards and lets in air to relieve vacuum pressure and no longer tries to vacuum up water. Simple to reset and would also work in case of other foreign debris ingestion like sucking up a plastic shopping bag into the intake.
Probably all low-likelihood scenarios, but if counting angels on a head of pin why not engineer a solution?

Treme... Very interesting stuff MLV. (My read: Mass Loaded Vinyl) Agreed on putting system in place before loading up on concern---TY for focus. Am going to do "blanket test" today to sort out if duct is resonating or noise is exiting at ends.


Coastr... pop valve is damm fine thinking. Could be electronically or mechanically engineered into system. At this moment, am not inclined to get more electronics involved in system. Will think it through mechanically. You're welcome to sketch-post an idea if you're inclined. (For entertainment & enlightenment, don't see anything wrong with counting angels on head of pin.)

Taking detour from mounting bracket (as the noted next priority) and “blanket test.” Reason… suggestion tabled is to consider frequency dampening from an alternative perspective---rather than subdue frequencies that motor produces… prevent frequencies from occurring. Door to this alternative noise-subdue possibility is ESC---it’s programmable to a degree with “timing” being the key. It’s possible that by adjusting timing, motor frequency may change… change for the better. (Assumption: sound frequency here is electric-motor’ish rather than blade-cutting-air’ish.) Now, forget noise...

Rather, this is a consideration of a brushless motor's efficiency. Premise… noise = inefficiency = wear & tear = maintenance & cost. Alternately, quiet = increased efficiency = increased durability = maintenance & cost reduction = good stuff.

http://forums.pelicanparts.com/uploa...1503065809.jpg
(Does not represent my card settings.
Am showing for ESC programming options.)

ESC - Electronic Speed Controller’s programming card in hand (above.) “Timing Mode” on my ESC is set “Low.” Why Low? Because with no understanding of how timing effects a brushless motor’s operation, I researched settings with majority of input suggesting “low” being the way to go. Bear in mind crew suggesting this to me... they're RC pilots. Do they prioritize noise reduction?

Where’s this heading? Programming ESC with each timing variable then operating motor at known noise-producing levels seems a valid excursion. (There’s an added point of interest here, that being my not recalling this high frequency when turbine/motor was run WITHOUT full ducting and bucket attached---seems I would recall an important detail such as this.) Nothing may come of this dig in terms of apparent outcome… or might be discovery with multiple recognizable benefits.

"To live in a sea of questioning... one's only life-raft-of-sanity is finding answers regardless of their individual appeal." --A. Senna, RIP

Played with system config and ESC timing mode. Skip to "bottom line" for what's been found.

TEST NOTES:

Run 1
System without: CEET duct & bucket
ESC with: original Speed Mode = Low
Speed runs (% of 100/full):
40
50
60
70
80
90

FINDING: 1. Straining to make out high frequency pitch at 80 and 90. No pitch at lesser speeds. (Different than yesterday’s run---with CEET duct and bucket attached.)


Run 2
System WITH: CEET duct and bucket attached
ESC with: original Speed Mode = Low
40 – no high pitch
50 – high pitch barely audible – has whistle-like tone – straining to hear it
60 - high pitch more audible – ominpresent… mostly at intake nozzle
70 – high pitch is annoying
80 – not testing
90 – not testing

Run 3
System WITH: CEET duct attached WITHOUT bucket
ESC with original Speed Mode = Low
70 – high pitch annoying – same as with bucket attached.

Run 4
System WITHOUT: CEET duct or bucket
ESC with original Speed Mode = Low
70 – high pitch there but not annoying


ESC Modification – Reprogram Timing Mode to: Middle
Also: New Cut Off Voltage = Low (ESC will operate until low battery voltage detected… then cut off)
New Timing Mode = Middle

Run 5
System WITHOUT: CEET duct & bucket
ESC with new Speed Mode = Middle
70 – same as last run / #4 - pitch there but not annoying

Run 6
System WITH: CEET duct & bucket attached
ESC with new Speed Mode = Middle
70 – Pitch is back to annoying

FINDING: 2. Possible CEET duct & air-bucket back-pressure generating annoying high pitch and/or… 3. Possible CEET duct & air-bucket creating resonance chamber.


ESC Modification – Reprogram Timing Mode to: High

Run 7
Run WITH: CEET duct and air-bucket attached
70 – Pitch is annoying

Finding: 4. Altering ESC “Timing” does NOT change sound production


ESC Modification – Reverting to Low Timing Mode
Reverting to “Low” timing mode because temp testing ESC and motor was done on that setting with no overheating.


“Blanket” Modification

Run 8
Cover all duct with blankets---10 layers.
System run WITH: CEET duct & bucket attached
70 – Pitch is annoying


Duct Modification

Remove CEET & bucket and attach straight, hard, smooth bore duct to turbine/motor house. Straight duct section has 80 degree hard duct bend attached to end. This duct is approximately same total length as CEET duct length.

Run 9
System WITH: duct modification.
70 – Pitch present but not annoying


Duct Modification

Connect bucket to end of existing smooth bore config.

Run 10
System Run WITH: hard duct with bend at end with bucket attached
70 – Pitch present but not annoying
80 - Pitch present but not annoying
90 - Pitch present but not annoying

BOTTOM LINE:

Something about CEET duct's presence is creating and/or accentuating frequency in system to the annoying level. Fact that with CEET at 70% speed is intolerable and then without it it's OK at 90%… am using this to affirm my hearing ability & bottom line thoughts.

CEET’s excellent in terms of being relatively smooth bore and flexible (so it easily accommodates arching over wheel and is easily formed/pushed into crevice)… but… musical characteristics are obviously unwanted. To those party to CEET’s intended use, no worries. Who could have known!?! ---Is taken in full stride. (RonO... tab is started for you Bro! :D)

Where to from CEET? Perhaps its thin wall has something to do with its musical nature. Thicker wall’d silicone hose might be answer.

KinkyK, might I suggest that you keep the CEET ducting and simply turn up appropriate tuneage to 11 (such as the following)?!?!

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^^^ Creative solution RonO. Nice tuneage... a touch too relaxing.

In that case! :D

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Karl,

FYI Attached is a photo of how the Air Force uses the CEET ducting in our environmental control systems. You can see the combination of the 4-5" metal (aluminum?) pipe and the CEET duct. I wonder if our CEET tube is any quieter than the one you picked up.

Just thought you may like to see another similar application.

Good Luck

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