Improving the cabin heat on a stock 170

R COLLINS · Post by **R COLLINS** » Thu Jan 15, 2004 2:14 pm

Thank God for Texas. It was 70 degrees here yesterday and all the pretty girls were wearing shorts.

RC

doug8082a · Post by **doug8082a** » Thu Jan 15, 2004 5:33 pm

R COLLINS wrote:Thank God for Texas. It was 70 degrees here yesterday and all the pretty girls where wearing shorts. RC

Oh sure... rub it in. The wind chill up here in MA right now is -20deg. F. Everyone's got their parkas on so you can't tell which girls are the pretty ones. For that matter, you can't even tell which ones are the girls

A previous job of mine took me to DFW quite frequently. I miss those wintertime Texas sights.

N1478D · Post by **N1478D** » Thu Jan 15, 2004 8:25 pm

I just got new glasses. They work well. Been testing them on those Texas sceneries.

Post by **GAHorn** » Thu Jan 15, 2004 9:16 pm

Dave and DensityDog: I'm not purporting to state that the cabin has "positive pressure'" or not, nor am I encouraging anyone to open that area up to the cabin. (In fact the opposite might better serve: see below.) I was only pointing out the relative lack of sealing of the cabin area relative to the tailcone. If one were to assume the cabin had excessive positive pressure, then dumping it to the rear fuselage is not the solution the guy named "Max" apparently thought it was, per Bruce Shipp's previous post. There is already ample openings between the tailcone and the cabin.
In fact, the opposite may be true. The tailcone might actually be a source of cold air to the cabin.
An example of that situation is the number of times a CO monitor sets off alarms until the tailcone is sealed off. Aircraft exhaust has been known to enter the tailcone through various openings and then travel forward into the cabin.
When I was taxiing around one day with my headset off my head I noticed how noisy that "sound box" tailcone is. I could hear every concrete seam the tailwheel crossed as it bumped. I imagined how distracting that must be to rear-seat passengers and decided to rectify it.
That's when I noticed the lack of bulkhead behind the hat shelf. I cut an appropriately shaped piece of 2024 aluminum sheet and using PK screws attatched it to the sta. 108.00 bulkhead on the aft surface, and then applied soundproofing to the rear surface of the 2024 sheet to prevent oil-canning. Made a huge difference in cabin noise level both taxying and in-flight.
As for cabin heat, I'm spoiled. My airplane is a '53 model with the much improved cabin heat and ventilation system AND I'm in the Texas "hill country". (I've seen more fabric on dental floss than those girls wear on Lake Austin.)

Dave Clark · Post by **Dave Clark** » Fri Jan 16, 2004 12:32 am

Yes George I have an aluminum piece fitted to the bulkhead above the hat rack just like you and did it for the same reasons. I,m thinking it's the right thing to do. But I also like the idea of the Javelin vent under the floorboards pulling any possible gas fumes out of the tailcone. It might also help draw heated air in the cabin but I'm not sure.

4-Shipp · Post by **4-Shipp** » Fri Jan 16, 2004 3:44 am

Reference the relative pressure inside th etail cone: A Canadian friend's 180 had a small air scoop located on the right side of the tail cone approximately at the same station one would install a BAS pull handle (it had nothing to do with the BAS handles, this is just to give you a reference point). This small scoop was pointed forward and would have acted to induce airflow into the tailcone and increase the internal pressure. Can any 180 owners (past or present) familiar with this scoop educate the rest of us?

I don't know if Max's scheme worked or not, but having seen the scoop on the 180 it made sense to me

Bruce

DensityDog · Post by **DensityDog** » Fri Jan 16, 2004 8:18 am

Oh ouch, gahorn. But I have read my prior posts and I see that I did not write "dump it down the tailcone", but rather to vent the air out the tailcone or to some other (as yet unknown) lower pressure area. You were the one implying the air would travel aft through the 108 bulkhead on its own. And yes, you are correct that it is a generally held belief that air moves from the tailcone forward into the cabin during flight. In my old 170 I always felt the cold air moving forward from the back seat area along the floor, especially on cold days with the heat on full blast.
gahorn, my thoughts expressed here are merely to stimulate thought and discussion among fellow classic taildragger pilots, not misread and picked apart, and they are not intended to be the last word on every subject, unlike some.

Max

Post by **GAHorn** » Fri Jan 16, 2004 8:46 pm

Note: In my previous post dated Thu Jan 15, 2004 3:16 pm ...I referred to a "Max" that I understood to be the owner of an airplane Bruce Shipp (4-shipp) had observed, and who had altered his airplane. Go back and read the post. Bruce started his sentence, " Max, at the Mineral Wells fly in last spring,..." and he went on to describe the modification of the aircraft. Now, several days later, I realize the "Max" of whom Bruce referred was NOT the owner of the airplane who'd flown it to Mineral Wells, but is instead our own dear Density Dog. This may (or may not) alter the tone of my previous post somewhat, as well as this present post which I'd already made prior to that revelation.

DensityDog wrote:Oh ouch, gahorn. But I have read my prior posts and I see that I did not write "dump it down the tailcone", but rather to vent the air out the tailcone or to some other (as yet unknown) lower pressure area. You were the one implying the air would travel aft through the 108 bulkhead on its own. And yes, you are correct that it is a generally held belief that air moves from the tailcone forward into the cabin during flight. In my old 170 I always felt the cold air moving forward from the back seat area along the floor, especially on cold days with the heat on full blast.
gahorn, my thoughts expressed here are merely to stimulate thought and discussion among fellow classic taildragger pilots, not misread and picked apart, and they are not intended to be the last word on every subject, unlike some.

Max

I'm sorry you misunderstood my message post, DensityDog. I neither "misread" nor "picked apart" your thoughts. My previous msg was in reference to Bruce Shipp's commentary regarding a certain "Max" who had altered his airplane with the supposed intent to increase ventilation between his cabin and his tailcone. I did not represent to quote you when I invoked the words "dump it down the tailcone'...that wording was my own choice. Further, I did not imply "the air would travel aft" ...I only addressed the theory behind the altered airplane. I addressed the issue of the openness of bulkhead 108.00 in the context of ventilation betwixt the two compartments, and that is why I pointed out that air transfer between the two compartments is most likely in the forward direction...not aft. In fact, in my opening sentence I specifically disclaimed to support the idea of cabin "positive pressure".
Emails and other computer-generated text, being devoid of voice inflection, can be easily misunderstood. If you felt "picked apart" the perception was an unfortunate leap to conclusion and not correct.
Finally, If Yours Truly is the subject of your comment about being the "last word" then I can only offer a disclaimer: To All: This is a volunteer position. My opinions and judgments are my own. If you choose to lend credance to, use, or be jealous of them, you do so at your own risk. They are worth what you paid for them.

4-Shipp · Post by **4-Shipp** » Sat Jan 17, 2004 5:12 pm

[quote="gahorn"]Note: In my previous post dated Thu Jan 15, 2004 3:16 pm ...I referred to a "Max" that I understood to be the owner of an airplane Bruce Shipp (4-shipp) had observed, and who had altered his airplane.

The gentleman who had the modified aircraft was "Stu", as identified in the subsequent post by Joe. I was just addressing that portion of my post to Max.

I just realized I in my post reference the vent on the 180 I miss spoke and called the velcro mod "Max's scheme". My mistake, as the intended schemer of record was Stu

DensityDog · Post by **DensityDog** » Sat Jan 17, 2004 6:05 pm

Thanks Bruce, I understood your post quite clearly. I wonder if Stu is out there, and could let us know how his heater works in winter!

Max

N1478D · Post by **N1478D** » Sat Jan 17, 2004 8:09 pm

DensityDog wrote:Thanks Bruce, I understood your post quite clearly. I wonder if Stu is out there, and could let us know how his heater works in winter!

Max

I was somewhat confused by the post. And it was very easy for me to see how George could be confused by it - he wasn't even there. If you need to hear only from Stu, we will wait and see if he responds. If you are interested in someone relaying his input, that can be done. Am not sure that Stu ever posts, think he just lurks.

flyguy · Post by **flyguy** » Sat Jan 24, 2004 12:52 am

MAX- SCHMAKS - DOGGY DOOS 44 SHIPS INA A NITE!!! FER PETE SAKE Y'ALL WHYNCHA TELL PORE OLE RUSS HOW TU HEET UP HIS CABUN?

RUSS IFFN I EVER GIT TU FLY EENY WHERE YA ARE I'LL SHOW U THE BEST SELUTION FER GITTIN HOT* IN A '52. NOW YER GONNA GO FROM SHINEY PURTY "STOCK' TU PURTY SHINEY "ALMOST STOCK" AN STAY WARM WHAL DOIN YER WINTER FLYIN! *cept fer gittin suma them purty gurl in shorts tu fill up yer seats

DFXXXX@#%^@$^^WQEF9ADPFK2693EEEEEEEEEE Get back in the box!

Russ, I can advise you that the mod that I have in '93D is the best for producing a liveable cabin environment in almost any temp. I have flown Ole Delta in -10F several times while living in North Missouri (mizrey!) and always had almost normal cabin temps. You will have to buy some expensive parts andspend some time doing the work but it will be well worth the time and bucks if you fly in much sub-freezing temps. '93 Delta already had the mod and I will forever be grateful to the fellow who did it.

If you want I will e-mail you some digital photos of the mod and look up the PNs for what you have to buy. Look me up in the directory for my e-mail address. OLE GAR

TP · Post by TP » Sat Jan 24, 2004 1:25 pm

Russ, here is my two cent's worth. Your heat exchanger is it the type that is a straight exhaust pipe with a heat muff around it? If so why not make it more efficiunt by increasing it's surface area . What I mean by this is add fin's or swirlers to the exhaust pipe in side your muff. Same principle as the fin's on the jug's on your engine. TP.

zero.one.victor · Post by **zero.one.victor** » Sat Jan 24, 2004 4:23 pm

Gary,could you elaborate on your cabin heat mods? Or must you decline a public description in order to avoid prosecution?

Eric

buchanan · Post by **buchanan** » Sun Feb 08, 2004 6:31 pm

Here is a FWIW and applies to the 180 conversion only and it is just now being installed so it hasn't been proven yet. With the AVCON conversion a 3" scat tube goes from the bottom of the front left baffeling to the muff. From there one 3" scat tube goes to the carb heat box and one 3" tube goes to the cabin heat. There is a 2" hole on the bottom of the carb heat box where the hot air is dumped over-board when carb heat is not in use. We put a flange on the 2" hole and ran a scat tube to be mated up to the 3" scat tube via a Y just forward of the cabin heat controller.

I have a question. Would adding a scoop deflector to the 3" intake on the left front increase the air flow without compromising engine cooling? I see older Cessna 150's have that scoop but with a 1 1/2" or 2" inlet. If the answer is yes, then how "tall" should it be?

My wife is a quilter. She made a quilt for my son's 1960 C-172 which attaches via gromets to the shoulder strap bolts and then attaches to the tops of the fuselage with velcro. You can still easily get to the back seats if they are installed or to the baggage compartment if the back seats are out. If you have back seat passengers the quilt can be draped behind the back seat backs and still offer quite a bit of protection. He says there is a BIG temperature difference between the front seat and behind the quilt. He is located 250 miles west of Fairbanks.

Buck Buchanan, Valier, MT

The International Cessna 170 Association

Improving the cabin heat on a stock 170

DOANT TAKE MUCH TU GIT ME GOIN!!!!!!!