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  #11  
Old 09-12-2019, 04:39 PM
rockbottom rockbottom is offline
 
Join Date: Nov 2009
Location: Fayetteville, GA
Posts: 41
Default anchor nuts

I installed two doors on my 8 with anchor nuts riveted to the perimeter of the door flanges in case I decide to remove them later on. I have had no issues with cooling but wanted to experiment with reducing the size of the exhaust outlet in an attempt to minimize frontal drag.

Because of the shape of the bottom of the cowl where the doors are mounted, I added a thin layer of micro reinforced with fiberglass on the outer surface of the doors to match the curvature of the cowl.

Using anchor nuts mounted on the flange of the doors required building up a layer of micro around the door opening on the inside of the cowl to provide a flat surface for the door flanges to rest on. I haven't had a chance to modify the cowl yet as desired, and consequently, have not had to use the doors very often to enhance cooling.
J Baker
RV8/IO-375/Hartzell CS prop/dual pmags
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  #12  
Old 09-12-2019, 11:38 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
Posts: 628
Default

I think I glued mine with proseal per the install instructions, but I'll have to verify that. The wiring comes with a little disconnect plug so you can remove your lower cowling.
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  #13  
Old 09-13-2019, 08:52 AM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 447
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The cowl flap did not make much of a difference in my -8A; maybe 3-4 degrees. Currently, it is not working, so I'm considering removing it in during my condition inspection.
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2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN
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  #14  
Old 09-13-2019, 02:56 PM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 447
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I should also add that my CHTs (#3 and 4) are only "high" on take-off during the summer on hot and humid days at sea level. Once in cruise, the CHTs are around 370 (cooler in winter) at roughly 2,000 depending on power setting - I usually have no reason to climb any higher. One issue that I have not investigated is fuel flow because last time I checked, it was 15.5gph on take off, which is low. The other is timing - I have SDS on one side, and I've been advised to retard the remaining mag from 25 to 23. Note that the "high" CHT was "high" before the installation of electronic ignition. I suspect that airflow through the cowling is not the main reason for my "high" CHTs, and why I haven't experienced a dramatic reduction when using the cowl flap.
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2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN
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  #15  
Old 09-14-2019, 05:10 PM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 447
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Adding a bit more detail, the FF on takeoff for the past two years varies between 14.9-15.9 GPH, which apparently is low. Since the airplane is in the middle of its condition inspection, I'm going to recheck the Red Cube to make sure it is accurate, and if it is, re-jet the carb. Have to read up on that procedure.

As for the cowl flap not functioning, I hooked it up to independent power, and it did not work. Subsequently I removed the actuator, undid the four cover tiny screws and discovered that the power lead negative side was broken at the flexible ribbon attached to the motor contacts. Not sure if I'll be able to repair it. Also not sure what broke the lead, maybe flapping around in the turbulence of the lower cowl? Bad decowling procedure? IDK. Probably going to plop some RTV at the point where the wires enter the actuator shell, and cable tie the wire to the actuator body if I decide to reinstall.
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2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN
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  #16  
Old 09-14-2019, 06:11 PM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,727
Default Proceed with caution.

AntiSplat have some good products but I have personal reservations about their electric cowl flap. These are my thoughts.
1. This device is installed in the lower cowl, generally in the vicinity of exhaust pipes that will be generating a lot of heat.
2. It is doubtful that the electric motor supplied with this device is capable of operating continuously in a high temperature environment.
3. The bottom of the cowl is an area where fuel for an engine fire can accumulate....consider oil dripping from the engine, or consider avgas dripping down from over priming. This is definitely not a location where you want to have an ignition source created by a faulty electric device.

Anyway, that’s my thoughts, bearing in mind that I tend to be pretty conservative about FWF matters.
Apart from the above I suspect that most of the overheating problems reported in Lycoming powered RVs are due to poor workmanship, particularly in the baffles, and that cowl vents/flaps are just a quick and dirty fix.
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Bob Barrow
RV7A

Last edited by Captain Avgas : 09-14-2019 at 06:25 PM.
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  #17  
Old 09-19-2019, 01:00 PM
Jbon Jbon is offline
 
Join Date: Nov 2015
Location: DFW
Posts: 55
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I installed a pair of Anti-Splat’s cowl flaps just last month. I was replacing a pair of 4”x5” louvers, and was hoping to reduce my climb CHT to below 400 F in the 100 degree Texas summer heat. To that end it was successful.

Installation was a snap, though I puzzled over how best to mount them. My RV-6 uses the older, thinner fiberglass cowl, so I figured I’d need to fill the resulting gap between the flange and the cowl somehow. In the end, I realized that because of the flange, there was no way they were going to fall out, so my installation became pretty simplified. I simply cut a hole with a dremel tool and secured the assembly with a flush pull rivet in each corner. To get the cowl flap door to lie flush with the outer skin, I had to stack some washers under the flange. The gap between the mounting flange and the cowl was sealed from the inside using pieces of metalized peel & stick duct tape. Nothing shows from the outside. It worked like a champ. I also used the tape to relieve the strain on the thin wiring where it enters the servo, as well as to secure and shield the wire as it runs up the inside of the cowling. Near the top of the lower cowl, I added an inline fuse in the positive lead, and a quick disconnect spade on the negative. This allows for easy disconnection of the wiring when removing the lower cowl. While I was at it, I added a couple of strips of the shiny tape to the sides of the servo motor to help reflect heat. I also added one of Anti-Splat’s heat shields to the left exhaust pipe to keep exhaust heat away from the unit. The right side didn’t need it because the heater muff served the same purpose.

One change I intend to make. . . The switch Allan provides is a two position (open/closed) type, so the flap can only be fully open, or fully closed. I want to be able to position the flap in a trailing position to provide some additional cooling with less drag when cruising at high power settings in hot conditions. Wiring in a momentary on/off/on switch should do the trick.

Overall, I’m very happy with the product and the installation.

-John

Last edited by Jbon : 09-19-2019 at 02:56 PM.
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  #18  
Old 09-19-2019, 02:25 PM
mturnerb mturnerb is online now
 
Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 1,092
Default

Quote:
Originally Posted by Jbon View Post
I installed a pair of Anti-Splatís cowl flaps just last month. I was replacing a pair of 4Ēx5Ē louvers, and was hoping to reduce my climb CHT to below 400 F in the 100 degree Texas summer heat. To that end it was successful.

Installation was a snap, though I puzzled over how best to mount them. My RV-6 uses the older, thinner fiberglass cowl, so I figured Iíd need to fill the resulting gap between the flange and the cowl somehow. In the end, I realized that because of the flange, there was no way they were going to fall out, so my installation became pretty simplified. I simply cut a hole with a dremel tool and secured the assembly with a flush pull rivet in each corner. To get the cowl flap door to lie flush with the outer skin, I had to stack some washers under the flange. The gap between the mounting flange and the cowl was sealed using pieces of metalized peel & stick duct tape. It worked like a champ. I also used the tape to relieve the strain on the thin wiring where it enters the servo, as well as to secure and shield the wire as it runs up the inside of the cowling. Near the top of the lower cowl, I added an inline fuse in the positive lead, and a quick disconnect spade on the negative. This allows for easy disconnection of the wiring when removing the lower cowl. While I was at it, I added a couple of strips of the shiny tape to the sides of the servo motor to help reflect heat. I also added one of Anti-Splatís heat shields to the left exhaust pipe to keep exhaust heat away from the unit. The right side didnít need it because the heater muff served the same purpose.

One change I intend to make. . . The switch Allan provides is a two position (open/closed) type, so the flap can only be fully open, or fully closed. I want to be able to position the flap in a trailing position to provide some additional cooling with less drag when cruising at high power settings in hot conditions. Wiring in a momentary on/off/on switch should do the trick.

Overall, Iím very happy with the product and the installation.

-John
How much reduction in CHT's did you see?
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  #19  
Old 09-19-2019, 02:54 PM
Jbon Jbon is offline
 
Join Date: Nov 2015
Location: DFW
Posts: 55
Default

Iíd say about 15 degrees, on average.

-John
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  #20  
Old 09-19-2019, 05:06 PM
PerfTech's Avatar
PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,404
Default

Quote:
Originally Posted by Captain Avgas View Post
AntiSplat have some good products but I have personal reservations about their electric cowl flap. These are my thoughts.
1. This device is installed in the lower cowl, generally in the vicinity of exhaust pipes that will be generating a lot of heat.
2. It is doubtful that the electric motor supplied with this device is capable of operating continuously in a high temperature environment.
3. The bottom of the cowl is an area where fuel for an engine fire can accumulate....consider oil dripping from the engine, or consider avgas dripping down from over priming. This is definitely not a location where you want to have an ignition source created by a faulty electric device.

Anyway, thatís my thoughts, bearing in mind that I tend to be pretty conservative about FWF matters.
Apart from the above I suspect that most of the overheating problems reported in Lycoming powered RVs are due to poor workmanship, particularly in the baffles, and that cowl vents/flaps are just a quick and dirty fix.
.
Ö. I think perhaps I should throw a few thoughts out as well for consideration, as I do have some skin in this game!
I was a bit concerned as were some others, in the beginning with the possibility of temperature degrading or damaging
the electronic actuators. To the contrary, this was not the case, with over 5K units out there and six years in service.
We have not seen one failure attributable to heat! We have had a few failures due to the original aluminum hinges
cracking ( all is the first 100 units). We have not had even one since we went to very heavy stainless hinges. We have
seen a few failures where the wires were pulled loose internally from not being restrained properly, or not being
disconnected before removing the lower cowl. The actuators are not a very likely ignition source for several reasons.
They are completely sealed, they are internally fused, They pull only .1 amp, we advise installation of .5 amp fuse
per two units to protect the wires as well. If you dead short the wires to ground the fuse will pop prior to wire heating.
Also worth mentioning is the fact they are only in use for 3 or 4 seconds per cycle. Considering all the aforementioned,
this product is hardly a risky ignition source. I can think of several items that offer far more potential for this type of
problem on all these aircraft.
Ö We see several aircraft weekly at our facility and on occasion we do see some poor workmanship, but its not the norm.
Most are average or above and some are fantastic. The RVs have very tight engine compartments with lower air flow
than most GA aircraft. They generally produce optimum rated output and most can benefit from added convenience of
the EZ Cool Flaps. This is nothing new or groundbreaking, as almost without exception GA aircraft manufacturers elect
to equip their aircraft with cooling flaps. If they weren't needed or desirable to have they would have elected to save
the manufacturing costs. Just my thoughts. Thanks, Allan..
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Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & Services
Info@AntiSplatAero.com
Southern California (KREI)
RV-9A / Edge-540
(909) 824-1020
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