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RV-7 N117TR

I have seen some that just put a large diameter disc of semi rigid foam on the hub then let it float there. The internal pressure (I assumed) pushed it up to the disc of the cowl. Any motion was just sliding against the cowl. This way the seal to the hub was snug and did not have to absorb any misalignment or wiggle from start/stop. Like yours, my cowl is hard to get on, but I have developed a technique that might work. The disc design might allow easier cowl install/removal. I will send a picture when found again :roll eyes:

Keep it going Andy!
 
Another interesting front seal design BillL! My current foam seal setup doesn't add any complexity to assembly/disassembly, the flap seal to ring gear underneath the weight ring would've complicated it.

I installed the wife's new dryer yesterday, after uninstalling it from the "free" setup and installation service....:confused: Anyway I used some of the leftover tape from the second installation kit to protect the surface of my prop spacer. I initially used 1 piece making sure the tape joint wasn't being peeled off by the rotation. I ran the engine for a minute and checked the foam seal, just a little smoking. After a couple runs and checks the seal "conformed" to the spacer and no more smoke, you can slightly hear the seal rubbing when turning the prop by hand. There was foam dust everywhere, but a quick blowoff took are of it. Here's the prop spacer/tape/seal interface after 1 trip around the patch.

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The seals were slightly trimmed down.

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I peeled off the first layer of tape to check for excessive rubbing and to reapply the metal tape without wrinkles. Everything looked good and wiped up easily, I applied 3 pieces of tape this time mostly wrinkle free.

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Initial flight tests show 5-10 degrees cooler on CHT's with oil temp the same as prior, although it's only the mid 80's not the mid 90's like several weeks ago. Both upper and lower cowling pressures seem to be up .75-1 inch H2O. Bumpy and clouds weren't cooperating but speeds seem the same. Enough time and fuel on testing, I'll continue to gather more data on upcoming trips.
 
Even though the large Al-647 bottle does fit under the seat back with 1/4 inch clearance with the regulator I decided to mount it on the right forward side of the baggage area for easier access.

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I wanted to tuck the bottle as far forward as possible for W&B as well as baggage space. This put the mounting hardware right in line with the flap weldment. Good news was the flap weldment had 5/8 inch clearance from the cover plate and a doubler/nutplates/bolt was just over 3/8 inch. The foam chunk and lines mimic the flap weld net movement.

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With nutplates and doublers installed.

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I used some thin cardboard to make a pattern for the upper mount/covey hole.

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Long ago I dented this donor .032 wing skin with a dead blow hammer while dimpling.

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I bent some 1/4 inch flanges for strength.

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I made a doubler with flanges and lightening holes.

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Bottle mounted securely.

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Looks good, Andy. I mounted my O2 in the same place.

Dave
RV6
130 hrs and still learning how to land
 
While I wait on an autopsy of my plane power alternator I figured I might as well do some more glass work.

I've been trying to play with different variations of re-shaping the lower cowling exit to get rid of the sharper corners. I installed a lower firewall bump/curve a while back in this thread http://www.vansairforce.com/community/showthread.php?t=112941

My current outlet is about 50 sq inches, I'm anticipating more airflow through the new exit and aiming for a 10-15 sq inch reduction on the exit size. I'm visualizing an elliptical exit that has radiused corners glassed into the lower cowling feeding the exit snugged up against the lower firewall bump/radius. Kinda a combo of the kindergarten cardboard sculptures below.
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Everything taped/waxed up and ready for some pour foam, my main goal was to get accurate placement of the lower firewall bump.

A173B4D7-C622-43C9-8694-EE867C85359D_zpsck1kskql.jpg


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Not sure the pour foam was a great choice, it took an hour to get the cowl off.

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She looks pretty ugly at the moment, I used a large concrete cutoff wheel to cut grooves into the foam as a kind of sanding gauge to rough out the shape. I'm doing a lot more staring and thinking then I am sanding, I hope to have the final shape in a couple more days.

96543855-7BB0-4CBF-B755-121369B15DBF_zpsofyk32zo.jpg
 
A little more shaping tonight, using the 14 inch cutoff wheel to cut radius guide marks into the foam worked pretty well for shaping the lower cowl exit. Pretty easy to eyeball a center for the cut and then measure from the cut off wheel to the cowling to keep things concentric. Kinda odd that I actually had a 14 inch concrete cutoff wheel laying around the shop from a totally different project.

AC6B079F-94BD-47B1-9F25-2BA7360F3B6F_zpspmbwihtk.jpg


You can see parts of the guide marks cut into the foam, basically just sand the grooves to the same depth or gently sand the grooves flush and it shapes itself.

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F0CE9C9B-A735-4C9B-BC0A-1529AC7EC2E5_zpsarpipshm.jpg


A paper towel roll is close to the same dimensions of the lower firewall bump/radius, trying to visualize how I want these curves to intersect.

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Looking good, funny, I used to use those beer box parts and same tape to visualize and make pattern stuff......too bad I don't drink beer anymore :-( now I go and steal all the wife's cardboard file folder supplies ;-)
 
A couple pics of my lower cowling cooling exit....

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2 layers of 8.9 oz glass and 1 layer of Lantor Soric, seams and edges all received a bead of Flox. If it works well I'm hoping to remove the foam/filler and reshape the aft 1/3 of the lower cowl.

C97086FC-8477-4473-AF3A-690519A3812F_zpstmthn5ne.jpg


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For now I think I'll taper the outside of the cowl to match the new contour and see what happens.
 
Andy, remove all the pour-in-place foam. Been, there, done that. Over time pressure changes cause it to swell in some spots and crush in other others. I had some inside wingtips and had to take it out. Had a bit more in my cowl mod and had to vent that area of the core.
 
Exit Fairing Update after 30ish hours:
As far as I can tell my CHT's and oil temps have remained the same in climb/cruise as before, but 2ish knots faster. I still haven't cleaned up the outside portion of the exit, someday....

I installed new Desser Monster Re-Treads and since the wheelpants were off I attempted to reduce the gap/seal the wheel pant 2 tire gap. I mounted my wheelpants slightly higher with a fairly large gap (.5-.75 inch) to minimize damage on grass strips. This is a pretty cheap and easy experiment since I'm using my old tubes for the seal and leftover weatherstripping adhesive. I started with a cardboard template, which probably would've worked well with a flat rubber sheet.

BF47AC2C-98CD-4CF1-8A51-D2CAE519A8BE_zpsziyhrv6l.jpg


I split the old tubes open and proceeded to cut and fit the rubber to the wheelpants.

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Because of the shape of the rubber tubes I had to use multiple pieces to fill the gap.

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Oversized rubber strips all glued and ready for fitting and trimming.

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On a positive note the seals conforms better than I expected, on the downside I need to remove several of the strips that were too narrow and make wider strips for the inside. They don't seem to cause a lot of friction between the tire and seal when rocking the airplane back and forth, I'm sure it'll get pretty warm at 60 knots....

EA077587-F8F0-4207-82A0-A8B697BF6C94_zpstsoz2ruv.jpg


FFF28386-2ACC-4E44-B1FA-8888EE6FF7AC_zpszoru0ytp.jpg


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I found it easiest to cut the center thicker part of the tube out first.

8C2CACD7-CDAB-4D69-A57C-1C088C4A2148_zpsnkwi1ohm.jpg


Then position the tube in the wheel pant and mark the edges with a sharpie.

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Larger side flaps added....

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nice

Andy,
This is wonderful experimenting!
I have seen others try or attempt to close this gap with baffle material or I think Lopresti even made operable doors. But nothing has proven practical for the masses. I even noticed Axle put front skirts on his RV4 pants for the racing circuit.
You rubber idea sounds promising.
Looking forward to your test flying results.
Are you concerned about venting/cooling the brakes?
Seems to me the EZ guys or maybe Klaus put naca inlets on the inside side of the pant to blow air on the brakes....assuming it would exit around the bottom.
Great pictures too....
 
Andy,
This is wonderful experimenting!
I have seen others try or attempt to close this gap with baffle material or I think Lopresti even made operable doors. But nothing has proven practical for the masses. I even noticed Axle put front skirts on his RV4 pants for the racing circuit.
You rubber idea sounds promising.
Looking forward to your test flying results.
Are you concerned about venting/cooling the brakes?
Seems to me the EZ guys or maybe Klaus put naca inlets on the inside side of the pant to blow air on the brakes....assuming it would exit around the bottom.
Great pictures too....

Thanks Bob!
Bob Axom/DanH/Axel and others' mods on the wheelpants got me wondering, I'll have to look up Klaus's EZ wheelpants.

We'll see about brake heat issues but a Steerable tailwheel instead of differential braking for steering will help. I'm also a "brake minimalist" when flying, a little preplanning is smoother and easier than replacing brake pads.
Pretty sure even without wheelpants our brakes only have 1 heavy application before getting hot and fading, the wheelpants seals will probably extend the cooling off time. After some normal flying I should test a "heavy brake application."
After writing the above a quick search yielded this thread:
http://www.vansairforce.com/community/showthread.php?t=121025&page=2
 
Thanks Bob!
Bob Axom/DanH/Axel and others' mods on the wheelpants got me wondering

Now you got me wondering. I have another wheel pant mod in the planning stages. I may have to incorporate this (if you don't mind). I was going to use felt.
 
Axel, copy away.

Dan, my final revision may end up very similar to your booties.

Did a short fuel/software/speed run yesterday, although the rear part of the seal stays put when hand moving the airplane on the ground I think the friction caused by the higher speeds grabs and tucks the seal into the wheel pant. The side flaps also seem to be rubbing on the outside of the wheelpants, but was also found tucked into the wheelpant. The front of the seal seams to be doing well.
You can see the aft portion of the seal tucked into the wheelpant which actually seals very well but not sure how long it would last, I don't think the side seals are sealing at all.

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No speed difference at all based on TAS, same 6000 PA and similar temps as previous flights. (TAS checked within 1 knt with NTPS 3 leg run)

I trimmed the side flaps and will do some more flying and thinking.
 
expaning foam

I helped with some Red Bull Air Race mods a couple years ago and to seal the pants we wrapped the wheel/tire with plastic/tape and shot expanding insulation foam into the gap, then trimmed it after cure. A pretty tight seal was achieved, and the tire rubbed away any foam that got in the way. No idea if it helped, were doing lots of other speed mods at the same time.
 
Like your ideas for speed

Mike, 3M weatherstrip adhesive from the auto parts store I had laying around.

84FD5B73-D682-4135-B613-A0FE0B3981A1_zpsnokdbjkd.jpg

Crabandy,
I have some ideas as well for my tailwheel.

I'll work them make up some working efforts and show my pix.

Keep it up.

Daddyman
dues paid +
 
Since my cowling/plenum work, oil temps have been about 10* warmer which is odd since CHT's are down. I'm attempting to remotely mount my oil cooler for more control over oil temps and also direct the air toward the exit. I'm trying to use most of my existing baffling, hoses and hardware. I'm attempting to place it about here....I'm thinking of securing the lower duct to the engine mount which will then hold the oil cooler.

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From what I've read a 3 inch (7.07 sq in) scat tube with a properly designed duct/hood over the oil cooler should be adequate for my 7 row Niagra 20002A. Folks with the larger coolers find 4 inch (12.57 sq in) scat tube is needed. Because I'm reusing my existing baffles, I made a square 5.25 x 2.00 (10.5 sq in ) inlet where the cooler was mounted.

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I made the curvy transition pieces using 5052 H3 aluminum (bends easier and sharper ) a few clamps and finger strengthening exercises....

AB93BD5A-1ACA-4014-87C2-E716BC2BC63F_zpsvcrm4uic.jpg


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I finished the last curved lip for the oil cooler inlet, I'm leaving everything cleco'd for now while I work through the rest of it.

D7F2D773-B5B4-4B43-9B5D-DC0F6D5BB1CE_zpszs6ejbq2.jpg


I glued some foam together with epoxy/micro and a couple long deck screws to keep things from sliding around. I added a small chunk of wood the size of the oil cooler fins as a reference point, also deters me from sanding the final shape too small. I made a separate chunk of foam for the bottom of the cowling that nestles into my exit.

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I trimmed the foam to fit inside the cowling and to semi mate to each other. I had to have the lower cowling installed to correctly position the bottom piece, it didn't leave a lot of room to work. Looks like the epoxy/micro exotherm'd a bit and melted some of the foam.

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I'm aiming to keep the exit duct for the oil cooler the same size as the cooling fin surface area, about 16.5 sq in, the duct exit is odd shaped to nestle into my lower cowling exit radius. I used a sharpie to scribble some rough shapes for sawing and sanding, I used a fabric sewing tape measure to keep things concentric. The melted foam/epoxy rib is gonna take a little more fixn, lots of work left to do but I have a rough shape...

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WOW

Andy,
I admire your ability to just tear into things. Not a thread redirect but about the oil temp, do you have piston squirters?

Nice radius work, do you have data on this or is it wishful thinking about the airflow verses pressurized plenum air? Thinking I have seen someone lately do a similar thing to direct flow through cylinders somewhere...can't remember now.

Quote: "I'm aiming to keep the exit duct for the oil cooler the same size as the cooling fin surface area, about 16.5 sq in, "
Why the "size" of the oil cooler?
Why not 125% of the input, allowing for thermal expansion?

Which input...the 10" opening in the baffling or the 7" duct opening?
I can appreciate your effort to pressurize the input air tapering down from 10 to 7.....but not clear on your exit thoughts.
I understand starting at the cooler size for attaching and gathering the air but you could taper to a smaller size to help fit better.
10 times 125% or 7 times 125%
or maybe you have found the actual free air flow number for the cooler?

Just 2 cents from a fan...
 
Andy,
I admire your ability to just tear into things. Not a thread redirect but about the oil temp, do you have piston squirters?

No squirters that I'm aware of, converted HIO-360-A1F6D to carb and 8.5 compression and electronic ignition. Oil Temp was really not a problem, me tearing into things probably is....
#4 has always been my hottest cylinder in climb by 20*, in cruise everything is pretty even. I had some baffle wraps left on cylinder 4 I wanted to pull off as well as see if I could direct a little more air into it. I also wanted to duct the oil cooler air toward the exit, just to see....


Nice radius work, do you have data on this or is it wishful thinking about the airflow verses pressurized plenum air? Thinking I have seen someone lately do a similar thing to direct flow through cylinders somewhere...can't remember now.

Mostly wishful thinking or rounded corner is better than square, I'ld like to say I've understood the old NASA reports on engine baffling but the pictures and summaries help.

Quote: "I'm aiming to keep the exit duct for the oil cooler the same size as the cooling fin surface area, about 16.5 sq in, "
Why the "size" of the oil cooler?
Why not 125% of the input, allowing for thermal expansion?

Which input...the 10" opening in the baffling or the 7" duct opening?
I can appreciate your effort to pressurize the input air tapering down from 10 to 7.....but not clear on your exit thoughts.
I understand starting at the cooler size for attaching and gathering the air but you could taper to a smaller size to help fit better.
10 times 125% or 7 times 125%
or maybe you have found the actual free air flow number for the cooler?

I went with the 10.5 sq in oil cooler opening because it was a split between the 3 and 4 inch scat tube areas and it fit nicely with the stock opening on the baffle.
I plan on a diverging duct to the face of the cooler that's about 16.5 sq in so I will lose some pressure.
Really didn't plan on thermal expansion of the air in the exit duct. I was hoping to maintain enough pressure differential to cool the oil well and stay above lower cowling pressures.
Really just a guess overall.
The cooler on the baffle had about 10ish sq in of fin area available to plenum pressure, the other 6ish inches were right next to the hot cylinder head with the exit blowing against the firewall. I'm thinking that moving the cooler off the hot engine and exposing all of the cooling fins to airflow will make the already adequate cooling even more so. I do plan on making the exit of the oil cooler duct slightly smaller to "throttle" the exit, it should give me a little leeway to open the exit slightly if I need more oil cooling.

Post #12 from this thread reinforced what I've searched online...

http://www.vansairforce.com/community/showthread.php?t=146953&page=2

Just 2 cents from a fan...

Thanks Bob, but I'm an amateur.....pictures prove it!
 
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Nice radius work, do you have data on this ...

Its hard to go wrong installing any sort of curved entry. There are lots of studies describing best entry into a duct. Velocity stacks are one example.

Three good illustrations here:

https://www.performancebyie.com/blog/the-right-bellmouth/

More comprehensive:

http://www.profblairandassociates.com/pdfs/RET_Bellmouth_Sept.pdf

Quote: "I'm aiming to keep the exit duct for the oil cooler the same size as the cooling fin surface area, about 16.5 sq in, "
Why the "size" of the oil cooler? Why not 125% of the input, allowing for thermal expansion?

Thermal expansion regularly gets dragged out to explain why exits should be larger, but the numbers tell the tale. Here is a table of volume correction factors:

http://www.engineeringtoolbox.com/air-temperature-volume-d_853.html

Note that raising the air temperature by 100F only increases volume by a factor of 1.06.

Neck down to increase velocity (no value here). Expand to increase mass flow through the cooler (what Andy wants to do). Why? Read here from our own resident Pro Airflow Guy:

http://www.vansairforce.com/community/showpost.php?p=1091150&postcount=39

Now see the cooler charts:

http://www.oilcoolers.com/LCHX_Specifications.pdf

First chart in each series says increasing mass flow raises heat transfer. Second chart says that mass flow is controlled by the pressure delta across the cooler, or in the case of a ducted system, pressure delta between the entry and the exit.

Which brings us back to the subject at hand. Andy, have you attempted to measure static pressure where you plan to terminate the duct? If it's the same as right behind the cooler in the original no-duct setup, you won't gain anything unless you expand the duct exit area as Steve described. You may even lose mass flow due to duct friction. If the duct is constant area, you must tap a zone of lower pressure to get more flow.
 
Dan,
Thanks for the extra reading!

I have measured the pressure where I'm terminating the duct and it is the same as the rest of the lower cowling I've measured.

I'm hoping to have some gains by moving the cooler off the hot engine and exposing 6 sq in more fin area to cooler plenum area instead of sharing the #4 cylinder fin air.
I have room to gain 20 *F of oil temp and still be fine for test flights. Instead of starting with a large duct and shrinking it to manipulate oil temps I'm hoping to start with a smaller oiler cooler exit duct and enlarging it to get oil temps where I want them.
 
Thanks

I love this...
Dan pointing me to all the data....
Andy doing all the work.
Me....learning...:D

Seriously, Thanks for reasoning and info....I do learn a lot!
 
I love this...
Dan pointing me to all the data....
Andy doing all the work.
Me....learning...:D

Seriously, Thanks for reasoning and info....I do learn a lot!

Thanks for the links, Dan. Note that the three inlets tested had very little variation in flow. A sharp edge is much much greater an issue than any radius at all. I did some port flow testing years ago and had some fancy test pieces made. Since there was not much difference, a sharp edge and some hand made clay pieces were tested to see how rapidly the loss coefficient changed. Even a clay, hand formed 1/4" tall inlet for a 2+" port reduced the loss by 20%. Very surprising. Also the exit loss with a sharp exit had a similar but lesser, effect. After that the improvement was smaller and smaller. So - the fact that Andy has a radius gives 90% of the benefit.

EDIT - DAN - 100F Increase is not 1.06, 30F is 1.06. The ratio of absolute temperatures.
 
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I used regular autobody filler to finish shaping over the foam, I can spread it and be sanding in less than 30 minutes. Probably took 7-8 layers, filled only the low areas first then slowly skimmed the entire surface.

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I used my router to notch a piece of plastic (wal-mart cutting board) 1/4 inch deep to form the off-set flange on the oil cooler and screwed it to the wood end of the plug.

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I laid some 8.9 oz 8 harness satin weave cloth over the plug and drew some reference/cut marks on the glass.

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I waxed and sprayed several coats of PVA on the plug as a mold release and laid up the first layer of the flange by the oil cooler.

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I was really hoping to be able to 1 piece this, it was not to be. I ended up snipping the wet glass and piecing it in. I think it would be more doable if I pre-cut it into 2 pieces.

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Are you going to melt the foam out from inside?
Melt/Chip/Scrape the foam out, the filler skin usually chips right off with the wax/PVA coating.
How many layers of glass?
I did 3 layers on the body of the duct, but 5 layers around the flange since I'm planning on it to support the oil cooler. Probably would've been fine with 2 layers of glass on the body of the duct and 3 layers for the flange, I have a tendency to overbuild and make things heavy.
 
The duct nestled into the lower cowling exit fairing.

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I trimmed the upper flange and clamped it to the oil cooler.

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I need to somehow clamp the duct in position with the lower cowling on so it fits correctly and I can glass some flanges onto the duct to attach it to the motor mount.
 
duct

Andy, If I'm seeing this correctly, one end is connected to engine (moving) and the other end to a fixed mount oil cooler. Something needs to flex. I could be missing something just looking at the pics.
 
Andy, If I'm seeing this correctly, one end is connected to engine (moving) and the other end to a fixed mount oil cooler. Something needs to flex. I could be missing something just looking at the pics.

Hard mounted cooler.
 
Andy, If I'm seeing this correctly, one end is connected to engine (moving) and the other end to a fixed mount oil cooler. Something needs to flex. I could be missing something just looking at the pics.

I'm planning on the oil cooler and exit duct fixed to the engine mount with a flexible duct from engine to the oil cooler which is almost my next step. My foam is already glued together for initial shaping!
 
You guys don't check me enough. Previously I wrote:

Thermal expansion regularly gets dragged out to explain why exits should be larger, but the numbers tell the tale. Here is a table of volume correction factors:
http://www.engineeringtoolbox.com/air-temperature-volume-d_853.html
Note that raising the air temperature by 100F only increases volume by a factor of 1.06.

Well, that's a misread of the chart, which is not change of temperature, but actual temperature compared to standard temperature. Duh.

I took another look because my sharp-eyed friend Mark Wesson wrote to say "Hey, what about Charles' Law?" The law states that, given fixed pressure, change in volume is proportional to change in absolute temperature:

V1/T1 = V2/T2

The absolute part is important; it means calculations must be based on degrees Kelvin or Rankine. So, converting 60F to 289K, and 160F to 344K for our 100F rise in temperature, we have :

1/289 = V2/344
V2 = 1.19

Thus based on temperature alone, and if there is to be no pressure increase, the outlet would be 119% of inlet size, not 106%.
 
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Well, that's a misread of the chart, which is not change of temperature, but actual temperature compared to standard temperature.
Thus based on temperature alone, and if there is to be no pressure increase, the outlet would be 119% of inlet size, not 108%.

EDIT - DAN - 100F Increase is not 1.06, 30F is 1.06. The ratio of absolute temperatures.

It took you long enough, but I knew you would get there!!! :D
 
I'm still reading oil cooler charts and the best way to fill pinholes.........I did jump ahead to the absolute temps though!
 
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Yeah, yeah, yeah...the edit time hack says it took you all day ;)

I was just being nice, giving you some time. I went to Chicago for brunch at Brunch just after the post and returned for the edit. Got to see the greening of the river, but (thankfully) missed the St Patty's Day parade. :p

Anyway . . . Andy, thanks for the posts. Dave Anderson said he made his baffle-to-HX duct in one piece so it fit both ends perfectly and then cut it. The gap is a saw kerf and sealed with neoprene glued to both pieces. Apparently, it spreads with thrust.
 
I noticed the same forward motion of the engine on my cowling-2-prop seal, I'm guessing a solid 1/4 inch or more.
As of now I'm leaning towards a flexible rubber boot like I made for the front cowling inlets if I can form a reasonable shape that won't pinch when wiggled, final shape still in-process.

Speaking of the inlet boots, I've noticed bug spatters patterns etc seem to flow pretty well through the top and sides of the round inlet say 7 o'clock clockwise to 5 o'clock. After flying through moisture, the bottom of the inlet 5 o'clock clockwise to 7 o'clock leaves a pattern like the ripples in water when you toss a rock in. Not much divergence here, the shape is pretty flat and shortly inside slopes up to the cylinder.

Here's the shorter left inlet...

23B1066D-12DC-4D07-AD7B-19DBB512A2E3_zpsuxizhzmm.jpg


And the longer right inlet...

D5905290-136C-494F-9B09-C49B722C38E3_zpsqqxedaei.jpg
 
I was just being nice, giving you some time. I went to Chicago for brunch at Brunch just after the post and returned for the edit. Got to see the greening of the river, but (thankfully) missed the St Patty's Day parade.

Seems like a good reason to me.

The interest here isn't really volume, but pressure, the argument being the exit needs to be larger so pressure doesn't rise. Given fixed volume (rather than fixed pressure), pressure would indeed rise the same 19%.

It does rise. However, what matters here is deltaP across the cylinders; raising lower plenum pressure also raises upper plenum pressure. And with a big hole in the bottom of our fixed volume container, pressure results in exit velocity.

Closest thing I have to cowl pressure vs exit area is some notes taken in cruise back in 2013. At a more or less constant airspeed, reducing exit area by about 50% (from aprox 46 to 30 sq inches) raised upper plenum pressure by 8.7%, while an exit pitot static probe showed an increase of 60%.
 
push the Easy Button?

Hey Andy:

Wouldn't it be easier to add a bluff body outlet to the side of the cowl? Tom Martin did this with excellent results - and it's easy to try different shapes before you settle on one size...and you get to tune the oil cooling without re-working the engine cooling...

The outlet for the 540 was remarkably small.

Carry on!
Mark
 
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