flyrotary@lancaironline.net Mailing List Archive

Aha! Something a bit different ok.

I don't have any experience pushing oil that distance. However, I would think extra care on initial start up is in order as I'm sure you are already aware. By that, I mean to make certain the oil system (coolers/line/filter) are filled with oil. Given how long it sometimes takes cranking to get oil up on a newly rebuilt engine, I can only think it would be much longer with that much volume in your oil system - before oil actually begins to flow - unless they are already filled.

I didn't catch the size of your oil coolers, but oil thermostats might be a consideration if you fly in cold weather.

Ed A

----- Original Message -----

From: bmears9413@aol.com

To: Rotary motors in aircraft

Sent: Monday, January 30, 2006 5:22 PM

Subject: [FlyRotary] Re: Cooling air inlets

Thanks Ed,

I also didnt mention that since Im building a Spitfire, I have two oil coolers mounted in scoops under the wings. I do have concerns of pushing oil that far. Anyone of any limits? I'll be going from engine to oil cooler one, then oil cooler two and back to engine. I havent actually measured it yet but I'm guessing that would be about 15' of oil hose.

Bob Mears

-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 30 Jan 2006 09:51:35 -0500
Subject: [FlyRotary] Re: Cooling air inlets

Hi Bob,

I fly a Rv-6A with a 13B. I started out using 24 square inch opening for each of the radiator cores AND 24 square inch opening for the oil cooler for a total of 3x24 = 72 sq inches.

I have since reduced the radiator openings to 18 sq inches each - leaving the oil cooler at 24 sq inches for a total of 60 sq inches, but I spent a lot of research and experimenting with the ducts to get the best pressure recovery I could.

I estimate (based on fuel burn) that I am producing between 170-180HP. Naturally the more HP you make the more cooling you need. So what may work fine for a 160 HP engine may be marginal (or worst) for a 180-200 HP installation.

50 sq inches will probably cool at cruise with no problem - however, it could be marginal or worst on a hot day with a max power climbout. A lot depends on how well the ducting and exit of the air is done. Ducting and associated detail is one reason why seemingly identical installations may vary greatly in cooling ability.

Its all about trade offs, given sufficient surface area and airflow - IT WILL COOL. However, you may encounter lots of cooling drag if you have not make an attempt to optimize your compromise.

Its possible that using one 50 sq inch duct (such as the James cowl) may be adequate (I believe Tracy Crook is intending to use such with a 20 B - so if it will cool a 20 B then there is little doubt it will cool a 13B). I am eagerly awaiting the results of using such approaches .

Ed

Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

----- Original Message -----

From: John Downing

To: Rotary motors in aircraft

Sent: Monday, January 30, 2006 9:22 AM

Subject: [FlyRotary] Re: Cooling air inlets

Bob; The 40 sq. will not cool the engine. Ed and others are using a 2 1/2 inch x 10 inch hole under the spinner for the oil cooler, as more than half of the engine cooling is through oil, as I understand it. I'm working on the oil cooler opening as well as the round holes to cool the coolant. My exit is currently 61.8 sq. inches, so it appears that I need to add some type of cowl flaps to exit more air. JohnD from the farm

----- Original Message -----

From: BMears9413@aol.com

To: Rotary motors in aircraft

Sent: Sunday, January 29, 2006 9:19 PM

Subject: [FlyRotary] Re: Cooling air inlets

That's good to know that you think around 40 square inches of air inlet will cool your motor. I'm planning to run an underbelly air scoop to the radiator that will have 51 sq. in. inlet. I had no idea if that would be enough. but from what you guys are saying, in should be sufficient for my 20B.

Bob Mears