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Will the anti-Splat cowl flap fit in a RV-8 cowl?

bobmarkert

Well Known Member
I am hours away from ordering an EZ cool flap ( http://antisplataero.com/EZ_Cool_Flap.html ). I'll then jump on a commercial plane from Denver to Alabama where my new RV-8 is in the paint shop. I have been fighting high CHT?s. After spending about an hour on the forum last night, I think this cowl flap may be the fix. One problem??, I can?t find a post that says it fits in an -8 cowl. The -8 has very little flat surface on the bottom of the cowl. Has anyone successfully installed the anti-splat ez-cool cowl flap in an -8 and did it require significant fiberglass work because of the tight curve of the cowl. Pictures?
Thanks
Bob
 
Bob,
It will fit nicely in the center section of the cowl. I just started my install. Cowl has been cut and an .050 shim was bonded to the interior of the cowl. Haven't yet decided to either rivet it in place or use screws.

Plans are straight forward other than than call out for the LED hole size is incorrect (too small). Wiring the switch is a pain since soldering is required, wires are super thin and a few jumpers are required.

Install should be completed this weekend. I'll post a few pics when done.
 
Pictures please

Mike, I'm having the cowl flap delivered to the paint shop in Alabama and I will fly in from Denver on Tuesday to install it. I have the Vetterman 4 pipe exhaust. I'm trying to remember how much room is left after the 4 pipes come together in the center of the cowl. I envisioned I would have to put it on the side on the bottom because the 4 pipes would not leave room in the center, plus that area is really hot. What exhaust do you have? Pictures would really help as you progress.
Thanks
Bob
 
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I have the 4 into 2 exhaust pipes which leave plenty of space for the cowl flap. it should also fit to the right or left of the center section of the cowl. There is a very slight curvature of the cowl in those areas that you may have to address with either flox or shims. You will need shims if you want a 100% flush fit. My cowl is 2005 vintage and needed 0.050-0.080 of shimming for a flush fit.

Will add some pictures this weekend.
 
Do AntiSplat cowl flaps work for you?

This is a pretty old thread, but hopefully some of you have tested them by now and can let me know if the AntiSplat cowl flaps actually do anything to lower the cht on climbout.

When hot and heavy my cht will go up to 435 or more unless I throttle back and lower the nose. This drops the rate of climb to about 500 fpm, so I am thinking of installing one or two cowl flaps.

But in considering the increased exit area, it does not seem to improve it by a very large percentage over the standard air exit around the exhaust pipes.

Does anyone have any real-world experience? Can I expect to improve my cht if I install them? I would like to keep them all below 400 even when climbing at full power at gross weight on a hot day.

Gordon
 
This is a pretty old thread, but hopefully some of you have tested them by now and can let me know if the AntiSplat cowl flaps actually do anything to lower the cht on climbout.

When hot and heavy my cht will go up to 435 or more unless I throttle back and lower the nose. This drops the rate of climb to about 500 fpm, so I am thinking of installing one or two cowl flaps.

But in considering the increased exit area, it does not seem to improve it by a very large percentage over the standard air exit around the exhaust pipes.

Does anyone have any real-world experience? Can I expect to improve my cht if I install them? I would like to keep them all below 400 even when climbing at full power at gross weight on a hot day.

Gordon
After researching and finding several good reports on added cooling performance, I decided to order one. It's somewhere between Spruce East and my house. Planning to install in the left side of the cowl lower surface. I have a 4 pipe exhaust, and don't want the actuator too close to the pipes, so center section isn't an option. Planning to start with one (side). If it makes some improvement, I may buy a second for the right, then (future) reduce the main outlet.

After fitting a template, it looks like the side area of the lower surface isn't not quite wide enough, so I'm sure some finish work will be required for the cowling. Temp issues about the same as you've described. But to answer your actual question, I don't know yet.
 
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Cowl flaps

I installed two of the anti-splat cowl flaps and am happy. My RV7 is based near Seattle but we are often in Ca or Az and they help on afternoon fuel stops.

Open them up on takeoff with heavy load and all is better.
 
have installed one cowl flap from AntisplatAero on the right side of my cowling, there is enough room for it. But the effectiveness is less than I expected. During climb out I can't see any improvement. During cruise there is a 10 degree F reduction of the CHTs ( takes about 10 minutes to see that 10 degrees reduction after opening the flap )
In order to reduce CHT temperatre during climb out it is important to have the air inlet ramps installed. Once I did that my climb out temperatures are even on hot days in summer below 400 degrees F.
 
Have you considered checking the "Delta P" between upper and lower plenums first?

If you can achieve 5.5" H2O differential at your climb speed, I don't know if I'd spend the money and effort towards a cowl flap.

If less that 5.5", then a Cowl Flap MIGHT help, but then developing an effective installation would require effort and discipline.


FWIW

mjb
 
Thanks for that input. My RV-8 is 2009, and the finish kit was circa 2007. I am not sure what you mean by the inlet ramps: is this something that was introduced after I got my finish kit?
 
Sorry - that reply and question was for Josef.

And for Marc - it is a good idea to measure the delta-P. What sort of pressure transducer did you use, or was it just a simple water manometer?

Gordon
 
Cooling

My ? eight kit is from about 2002. I do have the inlet ramps, and never get over 380 even in a prolonged climb at 80 miles an hour indicated on a hot day. Never flew without them but have read they contribute majorly to cooling. If you don't have them I'd sure try them. Not hard to install. Good luck!
 
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