joeq wrote:Well Mark V, (any relation to a BBC?), did you have your Franco very long?
My older brother, who's been tearing down motors since he was about 14, would have gotten the BBC thing right away. Me, I had to look it up.
My brother’s done several frame-up restorations, including a beautiful turquoise '66 GTO with three deuces. It wound up going across the stage at Barrett Jackson, a few years after he sold it to a collector.
He's working on a late 60's (I think) Chevy Nova SS wagon now. That's gonna be cool. I keep trying to talk him into restoring a '63 T-bird drop top (red with white top and interior, wire wheels, dual antennas on the rear fenders--that's my dream car), so he can sell it to me when he gets tired of it. But he never listens.
Yeah, I had two Francos for a total of 28 years. Got my first in '84 when we built our house. Didn't intend it to heat the whole house, just supplement the heat pump, keep the backup heat from running, and keep the basement warm--which it did nicely. Again, most heat output would be first 4-5 hours, then a gradual falloff after that. 8-10 hours in, it wasn't putting out much heat. However, I think because of the slightly deeper firebox compared to yours, I wasn't usually at risk of losing the fire until 12-14 hours. Depended a lot on the coal, though. I usually burned red ash nut, and last year my local coal yard sold me a batch of garbage red ash--I often had nearly-dead fires after only 8-9 hours. Sometimes I could save it, sometimes I couldn't. Never had such a mess.
Franco radiant stoves came in two basic models--a small one, and a larger one like I had--similar to your Surdiac judging from your pictures. Internally, I don't think F-B changed the design of their stoves in at least 30 years. After years of tinkering with dampers, draft, thermostat settings, etc. I got nothing better than I described above.
joeq wrote: I'm not familiar with the amount of hopper fed stoves out there, but from what I understood, the Surdiacs were a popular stove in their day. I wasn't aware there were so many models and styles. I'm not sure sure how to categorize coal stoves, but I'm thinking there are larger styles intended to be primary heat sources for an entire house, and at the other extreme, stoves built to heat smaller areas. I can't see using coal as a medium for "weekend burning only", considering how difficult coal is to light. Are there any hopper fed stoves that will heat a small house,(1000-2000 sq/ft), yet provide long burn times w/o any tending for over approx 12 hrs? And what is the benefit of a hopper anyway, if they sacrifice on coal bed space?
Based on my "vast experience" of five weeks burning a DS Machine 1500, rated at 96,000 BTUs, I can definitely say yes, there are stoves that can serve as a primary heat source for a home. If my setup was better--chimney and stove near center of house instead of at one end--I could come close to heating my place completely with the DS. Some of the larger DS Machine and Hitzer models, based on their specs, could certainly heat a home larger than mine (2250 sf on two floor, plus another 800 sf of basement). Obviously, the home must be well-insulated, and set up to circulate the heat from the stove through the house to get the best result. There are a bunch of threads on here addressing that.
After the F-B, the DS 1500 firebox seemed scary big when I first lit it. But the square firebox, with its area and depth, easily provides 24-hour burns. When it's very cold--low teens or single digits--I shake every 12 hours to keep it a little hotter, but it would go 24 hrs even then. With temps like today, I have the thermo turned back, and the stove's going 24 hours without attention--keeps the whole house comfy, and my heat pump hasn't kicked on once today. That is
sweet.
Re. the hopper...in the DS 1500 it feeds down onto the center of the fire, and holds a full 30-pound bucket of coal. The obvious benefit is to gradually let some new coal onto the fire as it "drops" when the coals are turning into ash--keeping the fire hot, giving a longer burn, and making tending less frequent. Unlike my F-B, which seemed to only feed coal when I shook it, the DS hopper does this effectively--If I check the hopper after it's been burning 12-15 hours, you can see the coal has dropped about 3-4 inches from the top of the hopper.
The other benefit of the hopper, as Franco B pointed out, is you’re feeding preheated coal onto the fire—like 400-500 degrees, as opposed to room temperature. Before I fired my DS 1500 the first time, I was freaked out by all the posts on here about puffbacks and explosions. Never had anything like that with the Franco, and I thought simply having a much bigger firebox would cause that. I think many of the stoves that do that, though, tend to be non-hopper hand-feds, so any new coal is going in at room temp. If you combine that with a 24-hour shakedown, I’d assume there’s much more time for volatiles to build up without the benefit of the “blues” starting up again to ignite them. Hence more chance of puffback.
In the DS, even at a 24-hour shaking, it recovers enough to get the blues going in just a few minutes. I’m careful to leave the ash door open a few minutes before shaking, so there’s plenty of hot coals waiting to reignite the volatiles. But the prewarmed coal definitely helps speed things along.
Sorry for the long response...unlike most others on here, I really can go on and on about burning coal.
I will admit, with my MPD totally shut, the stove does appear to be running longer. today i awoke to a brighter than average coal bed, even tho it was only about 5 hrs after it was scraped.
And relating to your car story, I like your brothers taste. I've been a Poncho fan for yrs, and had my share of GTOs. Unfortunately, they've priced themselves out of my market, so I'm left playing with Trans Ams these days. But don't get me going on this topic, or my computer will run out of ink. 
That's ok, the GTOs were pretty special. I only got to ride in my brother's a couple times before he sold it, but man, did it move. I also like the '65 and '66 Bonneville coupes and convertibles. Not exactly a muscle car, but they looked sweet. Think I built an AMT model of one those as a kid.