When I set out to build my RV-10 since this was going to be my "retirement/dream" airplane I set as a personal goal to stay as close to plans as possible for the airframe, and structure, but for the areas where the builder has options on various items, I determined that I would search for and find what for me was 'best of breed'. My decision to install the Will James Holy Cowl and the BPE Cold Air Induction IO 540x are examples of that 'attitude', however, it also left me looking for a solution for filtered induction air. After one of several Google searches, I happened upon Rod Bower's incredible device. Initially, I hadn't even thought about the added benefits of RAM air, so when I found his solution, it was like a bonus. I absolutely love simple and elegant designs, and in my opinion, this was absolutely one of the best I'd ever seen. A brief chat w/ Rod indicated that some modification to the cowl would be necessary. However, I've got a minimal amount of fiberglass experience (I'm at least not afraid of it, just don't like it), and after weighing the options of building and designing my own induction system to fit the Holy Cowl vs. making the mods to the Cowl to accept Rods Ram air. I decided the latter was the way to go. It turns out the modification was easier than I expected, I even made a mold of the result for Rod so that any who choose to follow would have an even easier install. The installation of the Ram/Filtered/Alternate Air unit itself couldn't have been easier.
This past year @ OSH I happened to run into Rod and his award-winning RV8 and during our discussion, he showed me the latest generation/update of his design. Boy, I didn't think it was possible to improve on what he had; but after seeing it, it told him “I've got to have one”. The new unit was a bolt-on replacement for the old one, even the holes for the mounting cable bracket matched the new canister. I'm in final assembly now, and can't wait to provide some data, once I'm airborne.
I wasn't that impressed with the induction filter Vans supplied, so I did some research on what was available for homebuilts. Reviewing some other builders' web pages, I found the induction system that was developed by Rod Bower Aviation. The system consists of a round aluminum can that encases the filter. The system also includes a ram air valve that allows the air to bypass the filter with a straight shot to the fuel servo. Since my engine uses a vertically mounted servo, Rod has an elbow that will place the ram air system in the correct position. The ram air kit also includes a modified induction scoop that takes the place of the scoop on Van's cowling. The scoop can be permanently installed or installed with camlocs. Since I have a 3-blade prop, I decided to go with the camlocs. This will make removing the cowling a lot easier concerning the 3-blade prop.
The ram air valve is closed during the ground operation mode (takeoffs, landings). With the valve closed, the air is supplied through the reed valves around the perimeter of the can body. A filter is used during the ground operation. In flight, the valve is opened to bypass the filter and provide a direct route of the incoming air to the fuel servo. The ram air valve is controlled by a push/pull cable. I used a Mac servo and a switch on the console to control the valve. When the valve is opened an annunciator light illuminates to remind you to close the valve for landing.
I wanted to let you know how well my Ram Air system's working on my new RV-10. I started my phase 1 flight testing in late July. After flying for about 10 hours I tested the Ram Air for the first time. At 8,500 feet, cruising at about 165 knots true when I opened the Ram Air valve. I was pleased to see an increase of a full 1.5 inches of manifold pressure and I could hear the engine tone change and feel the airplane accelerate.
In addition, I've tested it several times on take-off and climb and I can tell you that it is very effective. I see a decrease in runway used and the addition of between 300 and 400 feet per minute in climb rate.
I couldn't be more pleased with the system.
I have been meaning to write to thank you for a first-rate product. The unit fits my FM 200 perfectly. Also fits the Sam James Cowl perfectly. You saved me hours to months on the process of figuring out how to do alternate air, filters, etc. I hope to get the plane to Oshkosh next year. I will be happy to show it off for you.
The B-nut that connects the control cable to the air valve arm is a very nice, robust unit. I would like to get one to match my AFP fuel purge.
Anyway, thanks again. Couldn’t be more pleased.
RV 8 FWF
The new Rod Bower Ram Air induction for the horizontal air intake on my IO-360 is beautifully engineered and fits perfectly. It has increased manifold pressure by about 1.5 inches and airspeed of 3-4 knots. I highly recommend it.
Variable Oil Cooler Valve
Cold Air Solution
Flight tested this morning. The outside air temp was 46 degrees at 4,500 feet. Oil temp leveled off at 161 degrees. I closed the door about 85% of completely closed, (not sure what 100% would do) and the oil temp rose to 179 degrees. I then left it there for the remainder of the flight. Oil temp did not vary more than 5 degrees during loops, rolls, and Cuban 8's and then returned to 179 in level flight. No change in the descent, but at 1,000 feet, I opened the door to 50% because the outside temp was 58 degrees. After landing, I opened the door completely and taxied in with the oil temp reading 165 degrees. This unit works great and the installation is simple. I wish I would have done this two years ago, after the first cold flight. I would highly recommend this design for any cold-weather flying.
Fitted your induction kit to my RV8. Love it. 8 knots for nothing. Oil temp has dropped by 20 degrees due to more air available to go through the oil cooler. We had to modify the snorkel as it was too thin to allow unrestricted movement of the valve arm. I get a 1-inch map drop when the valve closed which reduces my speed by 6 Knots GPS. Thanks, Great work.
Longreach Aircraft Maintenance
Licensed Aircraft Maintenance Engineer
I am extremely pleased with the ram air installation on my RV-8. The aircraft is powered by an Aero Sport Power IO-360M1B6 with the Precision forward-facing induction system. The modification to the cowling to accommodate the scoop you provided was not difficult. I used baffling rubber that was hose clamped onto the filter housing to form the seal between the scoop and the filter housing. As you can see from the photos, I made the scoop removable to facilitate cowling removal.
As to performance, I routinely get more than 1 inch of additional manifold pressure. When flying formation with a couple of other RV-8s, we are even at full throttle and 2400 RPM. As I open the RAM air valve, I can feel the acceleration and hear my buddies complaining as I pull away from them! The top speed at 75% power is 194 kts. About 5 kts of that is due to the Ram Air system.
I have been flying. I see almost an inch increase in MP with the RAM air. Compared to my old, filtered air system with an automated alternate air door, I am seeing an improvement of about .4 inches when running filter only. The system was a breeze to install, and I appreciate the completeness of the kit and the quality of the components. Good stuff!
You called me on my cell yesterday. I told you it must have been a mistake because I had not called you. Anyway, I told you I loved your product, and you immediately asked for a testimony. Well, Rod, I don't know what to say other than it does everything you say it does. Yes, it was very easy to install. After I get to altitude, a very high altitude, above most bugs, then I throw the switch for the filter bypass, direct ram air. A jump you can immediately feel. Okay, maybe a little jump but a jump just the same. Another full inch of MP easy. It's almost the same feeling as when you retract the gear, but don't try that on an RV. I love it. Good stuff. It seriously makes a difference on cross countries.
N925LW (Lord Willing)
- Rod Bower's RAM Air System -
Over the last month, I have been working with Rod Bower http://www.ramairforhomebuilts.com/, doing some testing using his system on my EVO Rocket. We first used his standard air box and air valve and for my installation, it was not quite right for the 540 engine. The filtered air was too restricted at high power settings and the ram air valve was also a bit undersized.
I use a chase plane, Wayne Hadath in his rocket, to determine the effectiveness of any modifications that I make to my plane. In the past, at altitudes of 8000 feet, I used to show half an inch more manifold pressure than Wayne did. When I first installed the RAM air system I was not seeing any real improvement on those numbers compared to my previous system. Rod rose to the challenge and had a larger air box with bigger reed valves made. He also got a larger RAM air valve that has helped with flow. Yesterday Wayne and I did another test and I now have a full inch more MP than he does for an honest improvement of half an inch of MP using the RAM air system. With my previous filtered inlet setup I had not flown beside any other rockets that had a greater MP, so improving on that one is a real improvement.
The filtered take-off performance is now on par with my previous system but when you open the RAM door you can feel and hear the difference. Thank you, Rod, for going the extra mile to make this system work properly with my engine.
EVO1 300 hours
RV4, two HRIIs, and five F1s, and an RV7
I am a Corporate Pilot and CFII that has been flying Brooks Lemon’s Christen Eagle for the last year. Brooks has recently installed Rod Bower’s Ram Air system, and it appears very well engineered with a lot of attention to quality control.
Local flights and low-level training are done with the filtered air system activated but when extra power is needed the Ram Air provides an extra inch of MP. At normal power settings of 26” and 2500 rpm I will see an increase of 1” MP and you can really feel the extra boost when the Ram Air valve is activated. Normal cruise at 24” and 2300 pm will provide 140 MPH.
If I was to give this product a score for power and quality I would give it a 10.
Corporate Jet Jock
I have been searching a long time for a reliable, easy to fit ram air system for my Lancair and Rod had the one I needed.
Installation was easy with the attached instructions. After the first test flight with the new ram air, I was impressed. Opening the valve gives me an extra 1,2" Map for free, and you can feel the extra boost. The technical support is great. After a year Rod sent me an improved, bigger 3" valve for my IO-390, so I get even more extra pressure. The parts are machined in high quality. I can highly recommend this ram air system.
Lancair 390 OE-CCM