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Winter Flying?

Piper J3

Well Known Member
Flew today with OAT in high 30F. I’ve been working to seal some of the air leaks in the cabin as follows:

1. I made a cardboard bulkhead that fits directly behind the seatbacks and in front of the spar. This is fairly tight fitting and seals pretty well. The cardboard is a few inches shorter than the seat back frame.

2. I added boots to the stick openings primarily for safety (so nothing can jam the sticks) but also to stop loss of warm air from heater.

3. I added 1/8” x ½” foam tape to bottom of front canopy bow to seal against the sheet metal over the instrument bay. Works well.

4. Foam tape also added to bottom of canopy side rails and this works well too.

5. I made triangle foam rubber – approx. 4” wide with taper of 6” in back to 1” in front for side of seat bottoms against fuselage. Not happy here yet. Pilot and passenger still get cold air against hip and thigh at fuselage sides.

So here’s my question… I think I’m getting a lot of air coming from the main landing gear cutouts and also from the spar cutouts. Has anyone tried to seal these openings?
 
I just added L.G. leg and intersection fairings to try to seal the L.G. openings. I still have a significant air leak behind the seats. Have not had a problem with cold fuselage sides against our thighs.

To tell the truth, we looked at that air leak as an advantage down here in Florida but we were up in D.C. last weekend: 27 deg (F) on the surface, 6 deg at altitude and we pretty much froze our tushes off :) - cold air coming in from the baggage area and unable to get the engine temps high enough to keep us warm. I've fabricated a simple fixture to block a portion of the radiator if we go north again in winter. Not exactly sure how much to block off but it's adjustable and I'll have to experiment with it carefully.

Sure would like to know where the air is coming in, tho.
 
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"So here?s my question? I think I?m getting a lot of air coming from the main landing gear cutouts and also from the spar cutouts. Has anyone tried to seal these openings?"


I tell all my passengers thats the air conditioning system!
 
In snow country - -

you learn where the air is coming from. It comes in around the spar openings. I felt it was too complicated to try to seal those openings and not affect taking wings off. The flexible vinyl "divider" keeps the cold air down low from coming forward, and my Heater Damper Door makes great heat, and the plane an all season comfortable plane.
 
How I reduced the air flow from the spar openings

Pull the pins and roll the wings out far enough to get access. You can have a helper support the wingtips or rest them on a padded table or stand. Attach some sticky backed weather stripping foam to the fuselage skin surrounding the spar opening. Make it a good tight fit, the foam will be fexible enough to allow the spars to slide back in, but will do a pretty effective job of sealing the openings.

Someone was wondering why the wing root seals were not sufficient to keep air out. I do not believe that is where the air comes in. I believe the whole interior of the wing is slightly pressurized relative to cockpit air. Visualize those openings out at the wingtips that reside in the high presuure air area on the bottom side of the wing.
 
Hey BigJohn - -

I believe the rear of the canopy lifts a bit while flying and pulls a lot of air out thru. Even with the heater door open some, replacing some of the air escaping the rear of the canopy, there seems to be enough suction inside to pull the cold air thru the spar openings, and the landing gear openings. Some cold air comes thru the flap handle opening, ( likely from the gear leg opening ), and the spar openings. My simple flexible vinyl 'curtain' keeps the cold air in the rear and then it likely just goes up and out the canopy rear. I might try a foam seal around the rear of the canopy to see what that does to help. If you don't have cold air coming forward down low, and lots of real heat coming from heater, it makes it very comfortable.
 
I'm going to try experiment today. I'll use 2" blue painter’s tape to seal the gear opening at the outside of the fuselage. Likewise, I'll tape the wing root to the fuselage. My wing has rubber U-channel to seal top of wing root but I left the bottom of the wing open basically for drainage. I'll seal everything with tape today and report later after flying.

Edit 4PM EST - Well, I started taping and it really looked bad so I decided not to tape the gaps. Instead I added a little more foam rubber near where the wing pins attach and it helped considerably. I can live with what I've got going at present. There is still a pretty good draft going on in the baggage area behind the seats but I've been successful in creating an air **** which allows good comfort in front of the spar.
 
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Another question regarding winter operations... how do you block off part of the oil cooler and what oil temp do you try to achieve?
 
Another question regarding winter operations... how do you block off part of the oil cooler and what oil temp do you try to achieve?

It is easy to make an aluminum cover plate to block 1/2 of the cooler area, and secure it with the two mounting bolts. Watch your temps on climbout on warmer days, and if necessary climb at shallower angle and/or reduced power to keep the oil temp out of the red.

The much better solition, is to install an oil thermostat, such as the one offerred by Aircraft Specialties. Then you needn't worry about oil temps, and your warmup to 122F will be way shorter. Lots of previous threads on this.
 
Just a comment - -

As advertised, the Thermostasis oil therm will pay for itself with gas savings. Even in warmer weather, it warms up faster. No sitting and burning gas while waiting to warm up. You don't have to do anything. Whether winter or summer, it warms up faster. The type auto stores sell ( designed for trans cooling ) do not work as well.
 
Radiator Blocking

I made an aluminum cover to fit over the entire oil cooler. The aluminum plate is riveted to a piano hinge and connected to a cable so I can open it or close it in flight.
I'm thinking on making the same thing for the incoming cooling air for the engine because when it is below zero Fahrenheit the engine only gets up to about 125 degrees.
 
That's looks like a real good solution. I need to know if it will fit on the RV-12 oil cooler. Does it close off completely? Looks like it remains partially open probably for safety.

It is, indeed. It closes off 100%, if you want. Check it out with Van's !
 
I may actually do this sooner than later. I flew the RV-12 today with 36F OAT and oil is just shy of 160F with engine at sustained 5100rpm.
 
That's looks like a real good solution. I need to know if it will fit on the RV-12 oil cooler. Does it close off completely? Looks like it remains partially open probably for safety.

I installed mine when I lived in PA and now live in Maine and fly well below zero most of the winter. I can keep my temps up to 220.

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Slight mod to make it larger to fit over the oil cooler.

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Fully adjustable in the cabin in flight
 
Dave, No still on the cruise with the Rubin's. We will have a VAF hat sighting at the Panama Canal soon!
 
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Seal Fuselage Spar Openings?

I removed my wings last week while performing an inspection and remembered a post about adding foam rubber to the root rib in order to seal the fuselage spar opening. So I cut foam 1.5” wide and thick enough to protrude ½” beyond the edge of the wing skin. Foam pieces are full height of the root rib. One piece of foam on each side of the spar is held in place with double-side tape against the root rib. When the wing is slid in place the foam rubber compresses by ½” and seals the spar cutout in the fuselage. Full test will be next winter but reduction in airflow in the cabin is very noticeable. I think this is going to work a charm...
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I'll be real interested in how that works out. I tried something similar with weather stripping and it didn't have much of an effect.
 
I'll be real interested in how that works out. I tried something similar with weather stripping and it didn't have much of an effect.

Tom

You live in Florida. Maybe wrong approach for you. Try installing add'l vents...
 
Oh, don't need it at all while down here. Up north in November or so, another story ... ;)
 
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Somebody asked me for a photo quite some time ago. Had the wings off earlier in the year, took a pic and then didn't get around to posting. Was still working out how to upload photos - think I've cracked now, or at least I hope so! These seals work a treat.

Jack
 
Nice! Thanks for posting that. It?s about time to commence the condition inspection on ours. Perfect time to stick in some foam blocks.
 
I would suggest that the aluminum surfaces underlying any such foam blocks be coated with corrosion-resistant paint -- as it appears Jack above (or is it down-under?) has done. Over a period of time, the foam has the potential to entrap and hold moisture against the aluminum leading to possible corrosion.
 
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Can?t take the credit for the paint - I didn?t build it. The guy did protect the airframe very well. It was his third RV and he certainly knew what he was doing by the time he got to the this one - I?m the beneficiary of great workmanship!

Jack
 
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