Winter Blues

[MarkD 53]

I have been trolling the Forum lately with not much to add so I thought I would post the latest of my Avid activities.  I tried to enjoy a bit of flying a few weeks ago but with no heat in the cabin I was only good for about 30 minutes till my feet and hands got too cold to call it fun.  It is not as cold here in Western Washington as some places but on a clear day at 34 degrees and 85% humidity it seems that the chill goes right through a body. 

So I'm gonna fix that. 

I started building the components to add cabin heat to my Avid.  I can't put a "Muff" around the muffler so I built a smaller one for the header pipe.  It may not provide enough heat to drive me out of the cabin but should be able to take the chill out of the air.  I made a valve to divert the hot air to either the cabin or exhaust out into the engine compartment so there is always air moving through the muff and ducting and made it operate with a cable from the cabin.  All of this was sheet metal work.  It is all installed but it has been raining steadily since installation so I have not had a chance to do an OP test.

I do not have pictures yet but I will provide some in a follow up post.

Next I started collecting parts to build a "HACman" type mixture adjustment circuit.  I could not find anywhere a 6mm hose barb fitting for the carb tap off so I have made one in an hour or so on the lathe.  The only thing I have left to do is modify one of the carbs to tap the venturi for the low pressure port.  Maybe I can get the carb set up on the mill and do that this weekend.

Again, no pictures yet but I will endeavor to provide some pictorial documentation soon.

Fly safe,  Do not fly where you can't land.

MarkD

[akflyer 1427]

The most important part I have found for the heat muff is the air intake.  as in getting enough flow through the muff to put air in the cabin, but not too much that it does not have time to heat up enough either.  I wont even get into the pot scrubber debate here hahahaha

Looking forward to the pics and follow up posts!

[allonsye 85]

I have been trolling the Forum lately with not much to add so I thought I would post the latest of my Avid activities.  I tried to enjoy a bit of flying a few weeks ago but with no heat in the cabin I was only good for about 30 minutes till my feet and hands got too cold to call it fun.  It is not as cold here in Western Washington as some places but on a clear day at 34 degrees and 85% humidity it seems that the chill goes right through a body. 

So I'm gonna fix that. 

I started building the components to add cabin heat to my Avid.  I can't put a "Muff" around the muffler so I built a smaller one for the header pipe.  It may not provide enough heat to drive me out of the cabin but should be able to take the chill out of the air.  I made a valve to divert the hot air to either the cabin or exhaust out into the engine compartment so there is always air moving through the muff and ducting and made it operate with a cable from the cabin.  All of this was sheet metal work.  It is all installed but it has been raining steadily since installation so I have not had a chance to do an OP test.

I do not have pictures yet but I will provide some in a follow up post.

Next I started collecting parts to build a "HACman" type mixture adjustment circuit.  I could not find anywhere a 6mm hose barb fitting for the carb tap off so I have made one in an hour or so on the lathe.  The only thing I have left to do is modify one of the carbs to tap the venturi for the low pressure port.  Maybe I can get the carb set up on the mill and do that this weekend.

Again, no pictures yet but I will endeavor to provide some pictorial documentation soon.

Fly safe,  Do not fly where you can't land.

MarkD

  I'm all in Mark.

[EDMO 1078]

I will stay with the hot water heater - No CO involved...

EDMO

[MarkD 53]

OK here are some pictures of the cabin heat arrangement.  The last is a pic of the 6mm hose fitting I made for the carb. The carb modification has hit a snag.  I have 38mm type 54 carbs on the Hirth engine.  The castings are the same but internal dimensions are different from the 36mm carbs used on ROTAX engines. I have some additional, corrective, machining to do now to apply the low pressure tap.  I will detail this additional machining with pictures after I get it finished.

MarkD

[dynomike 91]

Very nice .interested to see how the heater will work.rotax makes a 6mm nipple .it's the steamvent fitting on a blue head

[ChrisBolkan 130]

Hi Mark,

have you considered electric seat heaters? They are very inexpensive, draw little current (heaters for both seats can be powered by the 582 alternator) and they are super warm. We all use them on the East side over here in the Tri Cities. There are numerous sources on the internet. Just look for the form factor you want (butt /lower back) and the power consumption. Don't exceed the power you have available. Anyway they work great. Really great. Fantastic. Seriously great for winter flying. When I had them in my MKIV I sandwiched them inside a pillow case and laid on seats. My friends Ron and Jeromie peeled their seat cloth back in their MKIV's and installed like a real car seat heat. Did I say they are fantastic???

ChrisB

[akflyer 1427]

I will stay with the hot water heater - No CO involved...

EDMO

damn near every small aircraft out there is heated by muffler heat.  Not too many are falling out of the sky do to CO.  That was a CO detector is for.  I had my cabin fill with CO after and exhaust spring broke but I just opened the door and flew it another hour to the home airport.  The water system is marginal at best and much heavier than the muff heat.

[MarkD 53]

I had considered heated motorcycle gloves and heated socks but the Hirth has only a lighting coil for an alternator and I really did not want to be wired to the airplane.  As far as the seat heaters,  I have no problem keeping my posterior warm!  In cooler weather I usually wear fingerless wool gloves and if it is really cold I have some fleece mittens I wear over them.  Feet are the real problem.  I hate cold feet ever since being a youth in Maine where I had cold feet from October to March.  Never again....when my feet get cold I'm all through having fun.  You may notice that the cabin heat inlet valve I installed will direct warm air directly to the pilot side rudder pedals....right where my feet should be.  I hope to be able to do an OP test soon and I'll report on how well, or if, it works.  I believe I only added about a pound (1lb) of weight total with the heat system.

By the way Chris, thank-you for posting the details on the manual HACman type of mixture control system.  Your postings on the subject were very helpful and informative.  Once I resolve the machining issues in the differences with the 38mm carbs I'll post a follow-up with details (and pictures).

MarkD

[RobS 52]

Sorry to sidetrack this thread, but what part of Maine did you grow up in Mark?

[Bandit 286]

I had considered heated motorcycle gloves and heated socks but the Hirth has only a lighting coil for an alternator and I really did not want to be wired to the airplane.  As far as the seat heaters,  I have no problem keeping my posterior warm!  In cooler weather I usually wear fingerless wool gloves and if it is really cold I have some fleece mittens I wear over them.  Feet are the real problem.  I hate cold feet ever since being a youth in Maine where I had cold feet from October to March.  Never again....when my feet get cold I'm all through having fun.  You may notice that the cabin heat inlet valve I installed will direct warm air directly to the pilot side rudder pedals....right where my feet should be.  I hope to be able to do an OP test soon and I'll report on how well, or if, it works.  I believe I only added about a pound (1lb) of weight total with the heat system.

By the way Chris, thank-you for posting the details on the manual HACman type of mixture control system.  Your postings on the subject were very helpful and informative.  Once I resolve the machining issues in the differences with the 38mm carbs I'll post a follow-up with details (and pictures).

MarkD

Thermacell insole boot heaters work great. No cold feet anymore. I draw air off my cooling fins. Works good from 20 degrees on up. At seven to ten degrees you just dress warm.

[ChrisBolkan 130]

Just to clarify I am not proposing Seat heat as the only airplane heat. It works best in conjunction with water or exhaust cabin heat systems. In my experience water and exhaust systems have not provided "comfortable" heat in the coldest of conditions because my Avids have been drafty and un-insulated. The seat heaters add that bit of comfort and luxury that just doesn't come from cabin heat alone. They don't weigh anything either!

[1avidflyer 1983]

I used a J C Whitney auto seat heating pad when I was flying in northern Mn winters.  Cost $20 and I plugged it into a cigarette lighter plug.  I would slide it into the back of my snowmobile suit.  Had to run it on low or it would be to hot.  My thinking is like this.  If the rest of your body is plenty warm, your feet don't get as cold then either.  I did make muffler shrouds for the 582 and Jabiru mufflers and they work quite well.  Jim Chuk

[MarkD 53]

RobS,

Family moved to E. Orland (N.E. of Bucksport) when my father got out of the AirForce (1966).  A couple of years there then we moved to Hermon (S. of Bangor) till I was a Junior in HS.  Then we moved to Idaho (1972).  You know....GI life style, move every couple of years just because.  After I got out of the Navy, I (Wife and kids still attached) settled in W. Washington, been here since 1989.

Chris,

I put a muffler type heater on the RANs S-6S, 912UL and it will drive you out of the cabin with OAT around freezing.  That is what made me decide to try one on the Avid.  Due to the small portion of available pipe to put the muff on I do not expect it to be as good as some but I hope it will take the chill off on all but the coldest days.  I'm strictly a VFR nice weather pilot any more so I'm not planning any trips in Icy conditions.  We have to get together next spring/summer.

MarkD

[Guest]

jealous! I've never had cabin heat that would drive me out of the cabin! My Magnum did better than my MKIV (150 HP of hot air going thru mufflers), but was still damn cold when it was below freezing out!

[Bandit 286]

My SkyRaider heater. The air is ducted into the cockpit from the engine.

[RobS 52]

Mark,

I grew up and still live south of those locations, but the company I work for has operations in and around the Bangor area, including Hermon. Beautiful state to live in . . . in the summer, but right now, not so much!

[MarkD 53]

RobS,

Yup I know what you mean.  I always liked the Fall season the best.  I have often thought about going back to Maine but then I remember the Black Flies.  We are pretty happy here in the West now.  When I was 16 I accomplished my first Solo in my Dad's 46 Champ on skis at Old Town.  Fond memories of my primary flight instruction way long time ago.

MarkD

[Guest]

 Mark, when I posted the pictures of my HAC system on one of the other threads here, I also included 3 documents that ended up sort of hidden within the pictures. There are two at the top of my installation pictures and one at the bottom of the carb mod pictures that might be of some help if you did not notice they are there. They would be easy to miss among the pictures.

Chris

Edited 15 Jan 2016 by Chris Bolkan

[MarkD 53]

Thanks Chris, I did see the PDF files, they were helpful.  The 38mm carb has a larger bore for the slide and the bore Is also deeper in the body casting.  When I drilled in the center of the cast boss for the low pressure tap the drill broke through the bottom of the outer ring of the relief bore for the slide.  Fortunately the slide has the same relief on each side.  I then drilled out the port to 1/8" and used a short piece of 1/8" brass tube to bridge the outer circumference of the slide bore.  I then drilled the port near the center of the venturi for the pressure tap  and used the 6mm X 1 barbed hose adapter I made to  press the 1/8" tube firmly in place.  Pictures will help a lot when I can get them.  The 1/8" brass tube does not interfere with the slide when the slide is fully bottomed so everything should be good to go.  I will try to get a couple pictures of the finished product when I get home tonight and update the post.

MarkD

[Guest]

Sweet! Can't wait to see it. I did not realize you were doing it to a different carb.

Chris

[MarkD 53]

OK got some pictures of the completed mods to the carb.  I do not do a good job of stopping work to take pictures. I am usually too involved in the mental aspect of figuring out what I am doing so I end up only taking pictures after I am through.

Descriptions: First picture shows the brass tube through the right side of the bottom of the relief groove for the slide.  Second is same view just pulled back a bit for better focus.  Third shows the slide and the bottom skirt showing that the newly installed brass tube will not interfere with the slide when it bottoms in the relief groove.  Forth shows a different angle on the slide.

MarkD

[Guest]

Interesting approach. Looks like it should work fine. Nice work!

[MarkD 53]

UPDATE: 

Cabin heat works!  That is one improvement I should have done hours ago.  Makes all the difference in the world as far as fun vs tolerating being uncomfortable.

The mixture control (manual HACman type) still needs additional flight testing.  I think the orfice in the atmosphere pressure line is too small.  The system works great at mid throttle settings but allows EGT to go high on full power (Wide Open Throttle) settings.  WOT should cause EGT to go cold with the main jet I have but during periods of high fuel flow I think the small orfice I initially installed (.070") is causing a lower pressure in the bowls than atmosphere pressure.  This is with the low pressure control valve closed. 

I'm going to open the orfice up in .010" increments and see what happens.

In the mid range throttle settings the mixture control works great.  I can set the throttle for just about any mid range RPM and tweek the low pressure control valve to obtain the EGT desired ((usually 1100F to 1200F).  I try to shoot for 1150F but as you guys know EGT varies with load a bit.

One of the big reasons for doing this is so I can throttle back and fly with a friend in his CH-701.  He only cruises at around 80MPH and I was cruising around 95MPH.  If I throttled back to cruise with him at 80 my EGTs were going above 1200F. I was getting tired of passing him then doing a 360 and coming up along side again just to have to do it all again just to keep EGTs below 1200.  He was getting tired of me always showing him how slow his 701 was.

I suppose I could build up a set of STOL wings and get some 21" or 27" tires then I would have to burn more gas just to go 80.  Maybe not....

MarkD

[lostman 198]

Mark,

Lots of questions for you on the heater. How comfortable is it making the cabin now? Also what did you use for packing on the ends of your heater setup? It doesn't appear to be connected to the exhaust other than friction. Is that correct?

How long is the heater shroud overall? I'm really wanting to do this to my Teenie Two but not sure if my short 8" pipes will give me enough area to heat it up much. I suppose even a little would help though. 

Kenneth