VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 10-24-2008, 07:46 PM
petehowell's Avatar
petehowell petehowell is offline
 
Join Date: Jan 2005
Location: MN
Posts: 2,304
Default DIY Plenum

I really like the sticker on the back of the baggage compartment that says EXPERIMENTAL - it (ok, the certificate) gives us the ability to try new things (within reason) and see how they pan out. I have already done this to varying degrees with things like headsets, nav lights, landing lights, interior lights, canopies, O2 systems and trackers. For the most part, they have worked out well and saved me a few bux in the process.

My latest musings were around a plenum for engine cooling. My cooling has always been OK, but I have always thought it could be better. So I set out to copy some plenum designs I have seen here and on the web. My only criteria were to make it reversible in case I liked the baffle seals better, and it had to be pretty cheap to make. I only have about $60 into the design, so I think I have that one covered. The reversible design worked out OK, too, but I think it led to a less than optimal inlet design.

Here is the finished product:



I started with a sheet of 2" stryo from Aviation Depot and started shaping with a surform and 40grit paper. The goal was to have the plenum fit inside the standard baffles and use the same holes for mounting.



Progress



Shape, fit, repeat. When I got close, I started fitting the upper cowl for clearance. Once it was shaped and I got a good fit, I blew off the dust and covered it in packing tape, and paste waxed it for good release.



I mixed up the EZ Poxy (good thermal properties) and applied 5 layers of 9 oz cheapo Fg cloth I found on sale at Av Depot.



I popped it off the mold, and trimmed the edges. Then, I fit it to the baffle sides and molded the ramps in place on the plane.



More to come in Part II.....................
__________________
Cheers,
Pete

Amateur Plane - RV-9A N789PH - 2500+ Hrs
Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN

Last edited by petehowell : 10-28-2008 at 09:21 AM.
Reply With Quote
  #2  
Old 10-24-2008, 08:20 PM
petehowell's Avatar
petehowell petehowell is offline
 
Join Date: Jan 2005
Location: MN
Posts: 2,304
Default Part 2

Here is the plenum trimmed, fitted with nutplates and installed. It is sealed with speed tape for initial evaluation.



Another View



And a final view after painting - the Sky Pig 2 enhances the background view.



I sealed the edges with black silicone and it looks pretty nice. How does it work? Well, it does seem to cool a bit better. On hot days, I can climb longer before I hit 400 CHT and back off. The cylinder temps are nicely evened out with the exception of #1 that needs a blocker(this is in work). Speed has increased 10 kts. Alex P and I have decided that you always claim 10kts on a drag reduction project. In reality I don't think it made a difference b/c the inlets were not resized. That may be the next project, so no real speed increase at this time.

Inlet as of now



Temps balanced nicely



Was it worth it? Qualified yes- no great transformation occured, but it does run cooler and the there is room for inlet optimization and area reduction that should lead to better cooling and less drag. 10kts - Always claim 10 kts........ I did have fun and learned a few things, too. And for an aviation project, it was cheap.......

Watch for Part 3 when I rework the inlets
__________________
Cheers,
Pete

Amateur Plane - RV-9A N789PH - 2500+ Hrs
Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN

Last edited by petehowell : 10-24-2008 at 08:24 PM.
Reply With Quote
  #3  
Old 10-24-2008, 10:00 PM
scard's Avatar
scard scard is offline
 
Join Date: Jun 2005
Location: Cedar Park, TX
Posts: 3,383
Default

Alright! I'm watching. Looks just like where I left mine, for now. Very interested in your exploration . Great work, keep going.
__________________
Scott Card
CQ Headset by Card Machine Works
CMW E-Lift
RV-9A N4822C flying 2200+hrs. / Cedar Park, TX
RV8 Building - fuselage / showplanes canopy (Done!)
VAF Advertiser
Reply With Quote
  #4  
Old 10-25-2008, 06:17 AM
pierre smith's Avatar
pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,922
Default Really nice work......

....Pete. Do a search on Alan Judy. He has really small inlets....removable ones for hotter days....and a pretty fast airplane too. There is an optimal inlet ramp and sides angle that I've read about somewhere. Someone on here should know and chime in.

Regards,
__________________
Rv10 Sold
46 years ag pilot/CFI
Air Tractor 502/PT-6
Building RV-12, Wings, fuse, emp complete. FWF in progress.
Reply With Quote
  #5  
Old 10-25-2008, 07:19 AM
AlexPeterson's Avatar
AlexPeterson AlexPeterson is offline
 
Join Date: Sep 2005
Location: Ottertail, MN
Posts: 2,510
Default

I noticed almost 10 knots speed increase just by being in the same hangar...
__________________
Alex Peterson
RV6A N66AP 1750+ hours
KADC, Wadena, MN
Reply With Quote
  #6  
Old 10-25-2008, 08:12 AM
petehowell's Avatar
petehowell petehowell is offline
 
Join Date: Jan 2005
Location: MN
Posts: 2,304
Default Thanks Pierre

I have seen Alan Judy's amazing work and will use it as a reference.
__________________
Cheers,
Pete

Amateur Plane - RV-9A N789PH - 2500+ Hrs
Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN
Reply With Quote
  #7  
Old 10-25-2008, 09:07 AM
FredMagare FredMagare is online now
 
Join Date: Mar 2006
Location: Kyle, TX
Posts: 580
Default

(these "how to" posts are always the best!)

BTW, Pete - I'm seriously considering stealing your paint scheme!
__________________
Fred Magare
GySgt, USMC (Ret.)
PP-ASEL&I, A&P
Frederic.magare "at" gmail.com
RV-9A N469MT
Reply With Quote
  #8  
Old 10-25-2008, 09:32 AM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,984
Default

I love it Pete! I keep thinking I need a "do-able" project now and again....that looks pretty simple - and simple is elegant design.

Paul
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #9  
Old 10-25-2008, 09:51 AM
petehowell's Avatar
petehowell petehowell is offline
 
Join Date: Jan 2005
Location: MN
Posts: 2,304
Default Complete Pic Sets

Here are all the photos in case anyone is interested:

http://picasaweb.google.com/fly.rv9A/Plenum#

http://picasaweb.google.com/fly.rv9A/Plenum2#

Set 2 has some captions.

Here are the materials I used:

EZ-Poxy http://www.aircraftspruce.com/catalo...ges/ezpoxy.php 1.5 qt is plenty = $35

FG Cloth http://www.3m.com/us/auto_marine_aer...ml?itemNbr=576 5 packs on clearance = $15

Damaged Foam Sheet from HD = $5

Shop hardware and leftover paint = $5
__________________
Cheers,
Pete

Amateur Plane - RV-9A N789PH - 2500+ Hrs
Amateur Radio - KD0CVN
Doggies Delivered - 25+
St. Paul, MN
Reply With Quote
  #10  
Old 10-25-2008, 01:02 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
Posts: 4,340
Default NOT JUST A COVER

Pete....... Dave Anders got his plenum chamber right after much research. It is not just a motor cover. Yes, and done right, you will see 10 mph increase.

Dave has made a number of modifications to his RV-4 resulting in a substantial improvement in performance. He is able to achieve a top speed of 260+ MPH. Here is a link to his notes.

http://sacrvators.com/Aircraft%20Efficiency%20N230A.pdf

Please be sure to read page 3 and page 8 .......good luck....have fun....
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:19 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.