[BloomerJohn]

Can somebody provide vendors who make a 3" air scoop that would be mounted just inside the left cowling opening to direct more air volume into the 3" supply line going to the heat muff? The Aviat Husky uses a 2" one to provide greater volume of air across the heat muff. I need 3" to surface mountable one. Thanks in advance! John Nielsen (living with sub-zero OAT's in this midwest winter!)

 

[Randy]

Can somebody provide vendors who make a 3" air scoop that would be mounted just inside the left cowling opening to direct more air volume into the 3" supply line going to the heat muff? The Aviat Husky uses a 2" one to provide greater volume of air across the heat muff. I need 3" to surface mountable one. Thanks in advance! John Nielsen (living with sub-zero OAT's in this midwest winter!)

John,

I think you will have difficulty getting much benefit from the approach you are considering. You would be trying to force more air through the 2" scat hose that flows warm air to the cabin inlet valve. A scoop may not be able to overcome the pressure that is already present in that 2" scat. I say this based on my experience with several different configurations and placements of naca vents with oil coolers and intercoolers on my RV7A airframe. I did have some success with a modified NACA with a helper scoop added to it, reaching out into the faster airstream to get some air. NACA vents can be a real challenge if using them in an attempt to flow air into an area that already has some positive pressure.

Adding a second heat muff and inlet for it might be an option. I know that this is an option for me with the new Vetterman "Trombone" system. I would think the normal cross over system might be able to accomadate a second heat muff, if you have room for a second cabin heat valve etc.

Another possibility to gain at least a perception of warmth is a 12 volt electric heater. I flew a Lake Amphibian for 3 years, and it came with a little 12 volt heater that would glow red and look like it was putting out some heat. I learned to just dress for the OATs I was going to be flying in to be comfortable

Randall in Sedona

Oh, I guess you could move down here as another option

 

[BloomerJohn]

Thanks for the insight...my muff and intake and all supply including through the firewall is 3". The current intake is simply a flush opening in the baffle separating the upper and lower side of the plenum. I tried a 3" soup can cut and taped in place with great results...now I am looking to replace the duct taped soup can with something that looks more appropriate. John

 

[Mike S]

now I am looking to replace the duct taped soup can with something that looks more appropriate. John

http://www.aircraftspruce.com/catalog/appages/ductflanges.php

 

[BloomerJohn]

Mike,
I have this flange now, but am looking for one that includes a 'scoop' that would protrude into the airstream inside the cowling opening to 'grab' more air. John

 

[rjbob]

John,

Randall in Sedona

Oh, I guess you could move down here as another option

Sounds like it just may work, Randy!

 

[Mike S]

Aha, now I know what you are after, my old Stinson had something like that for the cooling duct to the generator.

You might take a look at various aluminum aerosol cans that have a nice rounded dome like top--- like hair spray or such, cut out the parts that do not look like a scoop, install the rest??