Do You Use Ram Air Poll

[Zulee]

I have an 81 J and at altitude I noticed little or no movement in MP, so like many others I have it removed. 

[Steve65E-NC]

Use it on my E all the time  in clear air on cross country.  About 1" more MP.  Just have to be careful to close it in any kind of precipitation.

[FlyDave]

In my J I use it above 10K' in the climb adding 100-150 fpm. The only thing it does in cruise is burn an additional 1/2 gph.

[Skybrd]

Quote: Bennett

I have the LoPresti cowl on my M20J, and I regulary use the ram air above 5000' when the air looks clean.  I get between .8 and 1.0 " increase in MP with the ram air fully open.  The LoPresti ram air is quite different from the stock cowling. You can see this on their website and video.  Nice cowl, but expensive.

[jetdriven]

I'd like to fly beside a LoPresti J and check what their manifold pressure is with ram air and off against mine. I wonder if it is an airbox restriction being freed up, like an E model, or if it really rams air in to above ambient pressure.

[1964-M20E]

In crusie when high enough and I'm at FT.

[bd32322]

I have started using this recently in my 1987 J - in cruise it makes next to no difference - I see about half an inch MP. But in climb it does make a perceptible difference in climb - no hard numbers because I didnt note if I was smooth enough to maintain the same IAS before and after opening the RAM air while in the climb. But I think I have seen 200 fpm or a bit more.

I open it after 3000 feet.

[jkb458]

Quote: Steve65E-NC

Use it on my E all the time  in clear air on cross country.  About 1" more MP.  Just have to be careful to close it in any kind of precipitation.

[Seth]

My former 1967 F model had Ram Air and I didn't use it a lot the first two years, and then started using it more and more at higher altitudes in clean air and it is amazing how that extra inch of pressure turns into a few more knots.

The Missile has no Ram Air control.  I know the "winking" eye air intake does work well.

-Seth

[testwest]

We have the Lopresti cowl and get at least 1" of MP at 5000' WOT. It is a little less at high altitude due to the lower calibrated airspeed (a little less ram recovery). However, the Lopresti cowl also has excellent cooling margins for cylinders and OUTSTANDING margins for oil cooling compared to our stock 201 cowl. This allows climbing at Vz (1.316 * 86 KIAS) or 113 KIAS with cowl flaps either closed or in trail. Whenever the air looks clean we open the ram air.

We are down for an EDM-930 install. When that is done we will post some data from the unit showing application of ram air, and the resultant MAP change.

And yes, at very high speed it is possible to recover more than static air pressure.