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Anti Splat Cowl Flap?

boearl

Well Known Member
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Anyone have the Anti Splat cowl flap installed on their RV-10?

Thanks,
Ken
 
Anyone have the Anti Splat cowl flap installed on their RV-10?

Thanks,
Ken

Yes ! Two of them. It leaves you with options especially if you have a hopped up engine (10 to 1 pistons), which requires more heat rejection. No regrets at all on the install of two in the bottom of the cowl.
 
Reservations ?

Yes ! Two of them. It leaves you with options especially if you have a hopped up engine (10 to 1 pistons), which requires more heat rejection. No regrets at all on the install of two in the bottom of the cowl.

Did you have any reservations about installing servo motors in the bottom of your cowl. I’m imagining that’s where flammable fluids can settle (fuel, oil) and also where it’s very close to exhaust pipes and therefore very hot. Possibly not a good place to have an ignition source.

Are the servos you installed rated for a particular temperature and if so is that temperature realistic given the location.
 
I have one - in the left side not down very low. So far I'm seeing almost no difference in CHT's open or closed, nor in speed. But I'm still in break-in (18 hrs) and flying without pants. CHT's were 303*-330*F span yesterday in full rich cruise at 25 squared. Cooling has not been a concern for me so far.
 
Opened the cowl flap today in cruise - about 25 squared for break-in. My hottest cylinder dropped 11 degrees in one minute after opening the cowl flap. I think 342 to 331 degrees. That's as long as I did the experiment this time. Closed her back up. No real speed difference I could see, but there must be a small one. I have no louvers in the cowl, nothing closing the slot ahead of the nose gear leg. Standard cowl, no plenum.

Note: full-rich; OAT 37F today. I've had CHT's in the low 400's when I started phase 1 / break-in in warmer weather.
 
I've had them since first flight in 2015.



Just starting my annual this weekend, and I'm going to be taking them out, replacing them with stock louvers.


I've not been able to see much of a difference between them open and closed. And a few months ago, the wires leading to one of them broke right where they go into the linear actuator.


Now, I'm not saying that they aren't well made, or that they couldn't have a great effect on a different plane. In the location I mounted mine (in place of the stock louvers), it just didn't work. Perhaps outboard of the lower cowl bump would have made a bigger difference...
 
Thanks for your input. I have the louvers. Living in AL, I battle high CHTs, especially in the summer. I live in lower AL. I’ll look at outboard cowl flaps.
 
I installed two cowl flaps instead of louvers when I built. I had high CHTs during Phase 1 which I battled a number of way; sealing baffles, mag timing, servo jet, and a set of louvers much like the RV-7 ones. Good news is my temps are now manageable. I can't tell you how much each of the things I did helped but I'm keeping the cowl flaps.

200 hours in I only had an issue with one of the servos which Antisplat replaced immediately. No further issues with them so far. I assume periodically the servos will go out or break, especially around the wiring.
 
Thanks Justin. I looked at your blog. Nice job on the -10 and your blog. I really appreciate your input. Ken
 
Did you have any reservations about installing servo motors in the bottom of your cowl. I’m imagining that’s where flammable fluids can settle (fuel, oil) and also where it’s very close to exhaust pipes and therefore very hot. Possibly not a good place to have an ignition source.

Are the servos you installed rated for a particular temperature and if so is that temperature realistic given the location.

Well they're small enclosed motors and I would be surprised that would light off fuel in that spot with the airflow that's going through. Also, the only time they're energized is when you are opening or closing the flaps, so if you knew of a leak, just don't activate them. I've seen fuel leaks in that area on mine and other aircraft and it's amazing that things DON'T light off sometimes.
 
Well they're small enclosed motors and I would be surprised that would light off fuel in that spot with the airflow that's going through. Also, the only time they're energized is when you are opening or closing the flaps, so if you knew of a leak, just don't activate them. I've seen fuel leaks in that area on mine and other aircraft and it's amazing that things DON'T light off sometimes.

Larry, I must admit that when it comes to safety issues and backyard experimental products I tend to be a bit reserved, particularly when it’s fire wall forward. It’s easy to get fuel in the lower cowl from over priming. I’d be interested to know what the temperature rating of that motor is. This is the Experimental category so there’s a good chance that the motor has a very low temperature rating and was never designed to be used in such a harsh, high temperature environment. If the motor shorts out you can have an ignition source.
 
rv 10 cowl flaps

Cowl flaps are not just about cooling. Steady temperature = engine longevity. Engine oil cooler flap is a must in cold weather flying as are the cowl flaps. Shock cooling an engine as in a rapid decent on a cold day = shorter engine life. Flying a cold engine, oil temps below 180 degrees = condensation in the oil which leads to shorter engine life. Being able to regulate airflow to an air cooled motor for temp control makes sense that's why certified aircraft with six cylinders engines do it. Well worth the time effort and money to be able to run your 50,000 dollar motor within perameters at 20 degrees and 14,000 feet pulled back in cruise configuration 2100 rpm, 17 inches burning 10.2 gallons an hour. Oil temp 190, 1350 egt, 330 cht. That was yesterday coming back from oklahoma. Warm motor = cabin heat.
 
Just a counterpoint to the above...I have the standard cowl with no louvers or cowl flaps. I'm in the California central valley where it gets really hot in summer and have never had a problem with elevated CHTs (also 10:1 pistons). I think if you do a really good job with the baffles and then seal up even the little gaps with RTV, you probably don't need cowl flaps.
 
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