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freezing my tukus off!

J

jeff beckley

Well Known Member
Flying in -7 is really rough. I have the standard heat box and was hopping for some suggestions on how to get more heat.
 
jeff beckley said:
Flying in -7 is really rough. I have the standard heat box and was hopping for some suggestions on how to get more heat.
Click to expand...

1) Install something that serves as additional heat sink and airflow reducer in your heat muff. My heat muff is packed with stainless steel scrubbing pads.

2) Seal air leaks.

I've only taken moderate actions here by slitting a piece of foam pipe insulation lengthwise and putting a removable "C" shaped section between the canopy rail and canopy skirt. This really helps.

You can seal the little V shaped grooves between the baggage compartment back wall and the bulkhead.

Also, you can put little booties on your aileron pushrods to seal the openings where the aileron push rods enter the fuselage.

My personal experience is that with just the canopy rail seals and the scrubbers in the heat muff, my airplane is reasonably comfortable on days when the surface temp gets down to 10f AND the sun is out. Without solar heat, I think it would be very cold...
 
I agree with what Kyle says, but what would also help is to get the engine hotter by restricting air flow through the cowl.

That of course would involve some sort of cowl flap, more weight and complexity and before you know it, spring has arrived and who needs it. But, I figure if the CHT's could be increased from 290 to 375 without a hassle, there would be plenty of heat for the cabin. I've been thinking about a simple inlet baffle to restrict incoming air. I think Larry has done something like that with the RV-12 out in Nebraska.
 
Long Johns

You should see what Cub pilots wear in our neck of the woods when flying on skis to meet their buddies on snow mobiles out on the ice :)
 
jeff beckley said:
Flying in -7 is really rough. I have the standard heat box and was hopping for some suggestions on how to get more heat.
Click to expand...

I'm assuming that you've sealed everything up and you just need more heat?

I am currently in the process of getting more heat into mine. In my research I have seen the following ways of generating more heat.

1) Install another heat muff on the exhaust stack on the other side. Then run scat from the baffles to the new muff, to the old muff then to the heat box.
2) Install a longer heat muff (Aircraft Spruce sells them). Some folks swear by it, some don't.
3) Pull heat off of the oil cooler, then to the heat muff...then to the heat box. I personally don't think this is a very good method since a lot of us block off our oil coolers in the winter anyway.
4) Drill a hole and install a scat tube on the lower cylinder baffles (the ones that are usually included with the engine). Then go to the standard heat muff then into the heat box.
 
Also,

* At the baffling, reduce the opening for the duct going to the heat muff. I think I made mine a 1 or 1 1/4" hole instead of 2". Slower flow will heat up more.

* Lean the mixture more when/if possible -- higher EGT's make a difference.

* Heated seats.

* Warm thoughts....
 
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Higher EGT and CHT's :eek:

You will be heating your cockpit at the expense of your cylinder/engine life. If you can get 290 degree cylinder head temps, keep em!
 
Wow. If I use my cabin heat at all (sometimes in the winter) it is cracked open the smallest amount which generates nice warmth combined with all my canopy leaks. :rolleyes:
'Course I am in the southeast but it would have to get REALLY cold for me to even open it halfway. Anyway, gonna fly a dog tomorrow and temps should be around freezing when I depart. Might have to open it a crack and a half!
 
Lots written about this topic in the archives, do have a look. Basic deal is that it is fairly easy to keep comfortable down to about 20F OAT. But, much, much tougher with OAT's near or below zero F. Two heaters is a must, airflow control is a must (too much air = cold air, too little means nice hot air but not enough). Lots of cold air wanting to come in. It comes in via wing roots and baggage area, back of slider if so equipped.

One simple trick is to fill the baggage area with a couple fluffy sleeping bags. Also, fold a towel and stuff between fuse outer skins and seat, to act as a **** to keep cold air from the baggage (side by side discussion here) from spilling around seat.

Mixture and power settings are important, go for max egt.

The aircraft performance in really cold weather is simply unbelievable.
 
Also worth noting that it's waaay below zero here in Iowa right now - dang near everywhere/everything is COLD. :D (-11 actual temp in Cedar Rapids right now)

That said, some good suggestions above. :)
 
Simple Solution

Here's the simplest and best suggestion...

Put the plane back in the hanger!:D

I, too, live in Iowa and would not think of going flying when its this cold.

Good Luck,
Tom RV-7A N175TJ Flying (when its warmer)
 
great flying today in Iowa

Come on Iowa Guys! I too live in Iowa and went flying today, comfortably warm in the Beech Skipper. I've learned a lot about winter ops, and I think there are lessons to learn for a warm RV.

The Skipper is very tight, with only minimal air leaking in. The only significant leakage is thru the wing spar attach box, under my seat / legs. Putting my hat there seems to help a lot. In an RV this would be the same as aileron boots.

As an interesting aside, the Skipper has a large open air vent in the rear of the fuselage, connected to a grill at the back of the cabin with 2" scat. This remains open all year but is an airflow exit - no cold air comes in.

The Skipper has a single heat "muff", actually a shoud around the muffler. It produces A LOT of heat - in fact so much that I have to tape off the cabin side in summer to prevent overwarm air from leaking past the heat box. It really is amazing, when you consider that it is a small engine. The RV lesson I'm taking here is "have mufflers".

Next is the Reiff heater, discussed in another thread. Plane starts like its July. My RV will have a Reiff.

Next is the Battery Minder. My 5 year old wet cell Gill still meets new battery capacity, so winter is no problem. My RV will be on a Battery Minder (but no Gill!)

The last thing that I have is a $17 heated seat pad that I bought on Amazon. It plugs into the cigarette lighter and gets very warm (maybe even too warm). I'm toasty warm right after engine start. Highly recommended. My RV will have the built-in electric seats.

With all of this, I'm comfy down to -10F OAT. Of course, I try to run near max EGT to get the most heat I can, and I leave the power on longer in descent than I might normally. It gets cold quick when you pull the throttle back!

The worse part of cold weather flying is getting the plane into and out of the hangar. Aside from that, it was a great day flying. I woudn't want to miss winter flying - it is the only time I can ever get 1000 fpm climb rates!
 
I have to agree with the muffler solution...

...I found out yesterday that my -10 has dual mufflers and a 1/4" pull on the front heat will almost drive you out.

The mufflers are only about 9-10" long and I believe they'd fit most RV's.

Best,
 
Shouldn't available heat be from EGT?

David-aviator said:
I agree with what Kyle says, but what would also help is to get the engine hotter by restricting air flow through the cowl.

That of course would involve some sort of cowl flap, more weight and complexity and before you know it, spring has arrived and who needs it. But, I figure if the CHT's could be increased from 290 to 375 without a hassle, there would be plenty of heat for the cabin. I've been thinking about a simple inlet baffle to restrict incoming air. I think Larry has done something like that with the RV-12 out in Nebraska.
Click to expand...

The heat muff is installed on the exhaust pipe. I don't understand why it would matter what the CHT's were unless there is a different way of getting the heat for the cabin.
 
Come on Iowa Guys!
Click to expand...

Oh, yeah.. it's great flying. Great visibility, great performance. But, my "This is fun" meter has its limits. :) Honestly, just give me ABOVE 0 degrees and I'll go. Below that... I'll be in the shop. :)
 
hevansrv7a said:
The heat muff is installed on the exhaust pipe. I don't understand why it would matter what the CHT's were unless there is a different way of getting the heat for the cabin.
Click to expand...

The total engine compartment is so cool, the max EGT at peak is just barely 1300. I do believe egt is related to CHT, at least it seems to be. EGT's are much hotter when the CHT is 375 rather then 290.

Yea, I know 1300 should provide enough heat but at 10F it isn't. The heat muff is a not near the egt probe and the #4 pipe is no where near 1300 at the muff location.

A second heat muff would help and that will be checked out for install possibility. At present incoming air is from #3 baffle as per the plan and there should be room to go to a #3 heat muff and then across to #4.
 
David-aviator said:
Covers 2 pipes? You must have 4 pipes and it covers 1&3 or 2&4, that's a good set up. I will check it out. Thanks.
Click to expand...

On my -7, I have a 4pipe system from Vettermans and have a muff similar to this pic. Except inlet and outlet are straight.
RV4-4-pipe-exhaust-%28a%29.jpg
 
Heated clothes:
Widely used in the motorcycle world. Works great for a relatively small power draw. I've used it down to 23 degrees OAT, zipped along at 75 mph for over 12 hours at a time. The stuff works. Google gerbings heated clothes and read for a while. Lots of choices.

DM



dhall_polo said:
Save the Tuku's. Now that's a bumper sticker.

The temps are only so bad for part of the year. Is it worth it to 'fix' the airplane for a temporary phenomenon? I haven't tried any of this stuff in the link, but it looks interesting. Maybe someone has a pirep on heated clothing?

http://www.flyboyaccessories.com/store/index.php?main_page=index&cPath=65&zenid=01f863c6f1484e718e9247819dac108b
Click to expand...
 
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Heat muffs

I have seen a Vetterman straight pipe setup up with dual Robbins heat muffs....Double the heat sources... Double the volume....And my wife would be asking to turn the heat down ! :)
 
I solved my Heat Problem

Jeff,
Just saw your 1/2010 post on heat in your RV7.

I have a RV7A that was cold too. But I solved the problem.

I spent A LOT of time trying to address cold air leaks (pushrod boots, rear of canopy, up the sticks, along the vertical bulkheads next to my thigh, the baggage bulkhead, the flap pushrods,...), and wasn't getting anywhere. Every time I thought I plugged a hole, I'd get more air somewhere else. Even in Texas, it's cold in January and I was trying to fly in a heavy coat and gloves.

After discussing it w/ a friend, we decided the problem was Not air coming in - but air being sucked out around the sliding canopy/windshield fairing. I could slide a slip of paper between them when the canopy was closed. That leak created cockpit vacuum from fast air traveling over the windshield/canopy fairing. The vacuum caused cold air to come in where ever it could. So I put inexpensive foam weather seal on the windshield fairing so the canopy would seal against it when it closed. WaaaLaa, problem solved!

My standard heat box now provides PLENTY of heat and we fly in shirtsleves.

"Jerry"
RV7A
 
if you have vertical induction you can get vettermans mufflers. I have them and can wear a short sleeve in my 7 with 5degrees outside, nothing sealed up anywhere and no insulation at the firewall or the sides of the airplane. I do have the heat from the left side going into the panel vents in the winter time and I have seat heaters. I'm very happy with my 7 in the winter time. They also quiet down things real nice inside and out. I feel spoiled.
 
bsacks05 said:
Wow. If I use my cabin heat at all (sometimes in the winter) it is cracked open the smallest amount which generates nice warmth combined with all my canopy leaks. :rolleyes:
'Course I am in the southeast but it would have to get REALLY cold for me to even open it halfway. Anyway, gonna fly a dog tomorrow and temps should be around freezing when I depart. Might have to open it a crack and a half!
Click to expand...

Bruce: Tell us about how your heat is installed and what you did for cockpit sealing. Any other novel ideas that might help?

Thanks, Mike
 
heat solution

Hi,
We live in the northeast and installed a cigarette jack in the front and back seats of our new RV-8. I'm always freezing, but my heated motorcycle vest works like a charm. Seems like a simple and effective fix.
Regards,
Barbara
 
Heat improvement items

Solutions to cockpit heat issue are sort of elusive, and maybe the particulars from a few that hav solved or improved their situation will help ferret out good fixes. I have has limited success, reported below.

I flew this winter mostly in / around Virginia to Connecticut-- not the coldest December/January weather. My 7A is a tip up and has the one heat muff installation. When the ambient air at altitude was 25 degrees or colder, it was very uncomfortable. Particularly when there was no sunlight into the canopy due to nighttime or late day flight away from the sun.

I tried a flow restrictor at the front air inlet and noticed no change in volume (which was already low) or temperature. So, I removed that and added a stainless steel scrubber pad inside the heat muff, which brought about a barely perceptible improvement.

Later I experimented with opening the airflow into the tail cone by removing the top half of the baggage compartment and an inspection panel at the rudder. The result was, if anything, a slight reduction in cockpit heat, though I don't know if that was because more heat was escaping or more cold air coming in. I closed up those panels after a two flight trial.

I bought, but did not install, a second heat muff from Rick Robbins (recommended by Larry Vetterman), http://www.robbinswings.com/, who I found to be very knowledgeable on RV heat systems. Rick noted that air temp, not air flow, was the most common heat complaint. I held off on installing the second muff becuase 1/ I think I have a FLOW problem, not a heat problem, and 2/ there must be a more graceful solution given that I live in the South, for crying out loud. Maybe if I lived in Minnesota, just maybe....but not Virginia. As another post said, why should I carry the weight and complexity of another muff, more scat, more clamps, etc., for a season limited problem.

Lastly, I tried sealing the tip-up canopy with home-OWNER grade foam seal applied on the left and right mating surfaces on the canopy surface. This made the most noticeable change of all. Still not adequate, but it is warmer in the plane.

Anyway, spring is here finally and the problem has solved itself. :) But, before next winter rolls around, I will probably try 1/ a better cockpit seal, and 2/ reviewing the scat tube routing and the heater box sealing at the condition inspection. Once winter gets here, I am prone to try heated seats or better (electric?) clothing instead of the second heat muff.

Mike
 
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