I was just thinking as the cowl flaps except for enable better cooling also add more drag to the aircaft are they sometimes intentionally used as spoilers in real life?As I am really into dual engine props now, maybe a realworld pilot can shed some light onto this for me.Alex

I wouldn't suggest opening cowl flaps for added drag during an extended descent (~1000 feet). You run the risk of shock-cooling the engine causing all kinds of problems. The proper use of cowl flaps by some pilots I know that own planes with them is not frequent. One guy who just bought a new C182 says he almost always forgets to close them at cruise, close them while long descents from cruise, or open them up when preparing to landAnyway, the amount of drag produced by cowl flaps is going to vary considerably depending on the particular plane.

Does that guy use checklist? (-:

Yes, Cowl flaps when open do add drag to an aircraft, although the main reason is to keep the engines cool, certainly not to slow it down.Regards.. TrevVisit "The DC-3 Hangar"http://www.douglasdc3.comhttp://www.douglasdc3.com/1/dc3.jpg

In addition to your comment on adding drag, I can offer the following. On the Navy P-3 that I fly in real life, there is an oil cooler door on the lower side of each nacelle. They allow air that passes through an opening on the front side of the nacelle to escape after the air passes through the oil cooler itself. The oil cooler doors are opened and closed by the flight engineer as required to keep the oil temperature in the proper operating range.In flight the flight engineer can roll the aircraft left or right by opening the oil coolers on one side opposite the intended direction of turn. As the coolers on engines 1&2 [left side, for example] are extended down into the air stream below their nacelles, the aircraft will roll to the right, the result of deflected air flow. The roll is slow to initiate, but will result in turns in either direction without touching the primary controls. [Also turns out to be one of the many ways to mess with junior pilots].A tidbit for you to consider. Rick

I seriously doubt it. Thank gawd he doesn't have a plane with retractable gear! :-rollHe was asking around if anyone knew how to use a KLN94. I asked if the Cessna guys didn't give him a run-down on how to use it when he went to get checked out on it during the purchase. He said yes but he didn't remember much of what they said. He's only had the plane for 3 months, not exactly long enough to forget everything. He basically knows how to go direct anywhere, which he did to get back to Florida, but has no idea how to program a flightplan or how to get a GPS approach to come up. I worry about some pilots. At least he was in the process of getting his instrument rating. We met in IR ground school. Maybe a good CFII will "help" him out with his procedures.

I've pretty much ignored the cowl flaps on the few models that have them. Do they actually do anything in terms of reducing oil temp in the sim? I can't say as I've noticed anything but I'm not sure how dramatic the impact would be anyway.David

You can also push your door open with your left foot and compensate on the rudder with your right foot.

My experience on a C-47 (think DC3/R4D) was if I were comming a bit too fast they came in handy. In other words: rarely used, but a nice trick to have up your sleeve.

Well, Cowl flaps are important in a sim, just the drag alone should be implemented to reflect correct airspeeds, in my own versions I have them.. have not seen one in the releases (R4D-6) for example.Most of the time, they are in 'trail' position anyway :-)VERY IMPORTANT to have Cowl Flaps work correctly in a sim.. maybe FS2004?Regards.. TrevVisit "The DC-3 Hangar"http://www.douglasdc3.comhttp://www.douglasdc3.com/1/dc3.jpg

From what I read in the FSD forum the reduced temp is modeled in the sim. However the drag is not as well as the pitch change while extend/retract. That is why some 3rd party add-on developers link the cowl flaps to the spoilers instead of the original FS command.Also the original FS commands do not allow for a separate control of the left and right cowl flaps. I guess this can be done with the latest FSUIPC though. I do not know if this also has a separate temp effect on the separate engines. I have two axis left, so I linked one with the cowl flaps, and the other one with the spoilers, as normally you would move both flaps at once anyway. Thus I have all 3 effects provided that the plane is done that way:1. pitch change2. temp change3. drag changeAlex

Thats what I thought. Thx fr all the answers and participation.Alex

>Well, Cowl flaps are important in a sim, just the drag alone >should be implemented to reflect correct airspeeds, in my >own versions I have them.. have not seen one in the >releases (R4D-6) for example. >>Most of the time, they are in 'trail' position anyway :-) >>VERY IMPORTANT to have Cowl Flaps work correctly in a sim.. >maybe FS2004? For what it is worth, the effect cowl flaps have on both drag and engine temp are correctly modeled in the Fly series.

I go with that too :-)Cowl flaps on the Seneca five are not speed limited and do add a fair dollop of drag(you soon notice if they have been left open in the cruise ;-)I will use them for short periods if I need extra drag and they are an extra trick up your sleeve, but certainly not for long descents etc.Going into major airports where you are being slotted in with the jets I have been asked to maintain 160 kts till very short finals which means flying down the glideslope clean and then having to slow up fast to flap and gear speeds.In that case the cowl flaps are a useful tool to act as mini airbrakes ;-)Where the drag should be modelled is in light twins where they do make a difference on single engine work.Peter

Hi Rick!I used to fly P-3's out of NAS JAX back in 1991 and 1992. I'm glad you bring this up because on a particular situation we experienced with a semi stuck aileron, we were able to trim the aircraft by opening the oil cooler doors. It was actually an experiment gone good for us believe it or not!!!!!!!Cheers mate!Sincerely,Dennis D. Mullerthttp://www.aavirtual.com/images/aav205_banner.gif[/img]