Some Ideas, or wild a guessing
and three virtually ineffective adjustable NACA vent things in canopy fairing skirt (2 in aft, 1 in fwd seats). Thinking about Van's RV-10 fuse side panel tilt-out doors at front and rear seats, plus exhaust vent under baggage compt floor. Thanks for input.
If you search the web the forums there is some good info. I posted some info. Due to prop wash the canopy NACA vents are pretty poor. However I put some VG's vortex generators in front of them. It is hard to describe and don't have a picture, but
>two VG's
>The VG's are about 1.25" to 1.5: long and 1/4" or 3/8" tall
>The front of the VG's can be radused, looks good ....
>VG's fwd of the NACA scoop on the either side of the NACA center line
>VG's angled about 20-30 degrees from the center line, closer together at fwd end than aft end
>VG's are about ~1" apart at front of VG and wider at the aft end because they are angled of course
>VG's aft ends will end about where the scoop starts.
VG......................./
flow of air >>>>>>...<[[[[[[[scoop]
VG.......................\
The back-slash and fwd-slash are not at the proper angles, but it shows what I mean. This is not my idea but I tried it and it worked. I think the credit comes from an old RVator. I forgot which one was more affective but with the above VG's the flow went from nothing to something on one and light to excellent in flight. The VG's where alumunyn T's with two way tape. They where real VG's. The plane was white with the gold anodized VG's in front of the NACA scoops it looked good. I had spares thinking they would fall off and experiment. They never did fall off and it worked so well from the first itteration I left them alone. The angle distance and postion fwd/aft I just made it look good. WHAT DOES IT DO? It trips the boundry layer and keeps the prop wash from dominating across the NACA scoop, I think.
For taxi I had a custom partial canopy holder that keep it cracked and there was no problem with breeze with the big fan shouving air (prop).
Also you should reduce leaks into the cockpit from the aft baggage compartment and alerion area. It may seem good to have air come in but what it does is fight your vents and keeps air from flowing.
The three golden rules of HVAC (heating ventalation and air condition) for comfort is:
Temp: Not much we can do about that
Humidity: Not much we can do about that
Flow: Convective flow, not statignant.
The latter rule is where we get our comfort, that feeling of air flow across the skin. This is why a fan works even though it is not AC.
So how do you get more air flow into the cockpit from the vents. You have to get OUT FLOW. Makes sense. If you seal the heck out of the cockpit you really are not going to get AIR FLOW across you for comfort. In some of my other post I talk about putting in a belly scoop to get that flow.
A lot of leaks around the canopy in all models are both in and out. You will get these little leak couples. None of it is reall good since its not in your control. In winter they make cold drafts and in summer they keep the vents (or heater) from working well because of the issue of pressureizing the cockpit, fighting the vents where you DO want air from. I found my RV-4 leaked like crazy around the aft canopy. I sealed it as best I could. It did not pose much of an issue. I flew in a very temperate North West and heating was more important. I few solo mostly in the cold months and in the summer, X-C's with a passenger, temp was not an issue, since it was mostly at altitude where its cooler. I also had two pretty good vents on the canopy front and back, left side after the VG's where put on. I never tried to improve the HVAC so to speak till I sold that plane. My RV7 is a little different and plan on trying the belly exit vent.
From Walmart I got some sun shades that have suction cups. The Girlfriend never complained but than shes a trooper. The idea is to get to altitude and
The POP out RV-10 scoops might be OK, they are going to be more drag, but you can retract them and adjust as needed.
OUTFLOW EXIT VENT
I personally have not done this but a RV-8'er did, but I am a BIG FAN of this idea. I have been thinking of this for a good bit. Again serach the forums, I have some post with pictures. He found that leaks around the aft canopy caused air to leak in on the neck of the back seater in cold weather. None of the heat was making it to the back seater. He put in vents on the back deck of the fuselage and ducted it to the belly. Problem soloved. In this case he was he was not really so much as sucking cold air drafts out but causing a low pressure area that DREW the warm air from the heater in the front registers to the back. Same principle will work with cold air.
If you don't have air going through the cockpit it is static and causes it to be uncomforatble hot or cold.
