B&S 49-series (810cm3/49ci) for aircraft use - TiPi's Q&A thread

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Chilton

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Maybe the carb heat should be half on normally all the time. The pilot could "override" this carb heat momentarily for takeoff with a spring loaded gate valve that snaps back to normal.
That sounds exactly like the DH Gipsy engine system, the warm air (not hot as it comes from around the cylinders not the exhaust) is the normal feed and the selector flap is spring loaded to this, the last half inch or so of throttle lever travel over rides the spring and selects cold air for full power.

This is one of the reasons why DH teaching was to pul the power back slightly at around 500 feet on the climbout to give the engine warm air. It is not necessarily a good habit to carry forward to the Lycoming and Continental engines.
 

rtfm

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Hi,
Not sure if this has been mentioned before, but the Valley Engineering Big Twin has a small outlet drilled in the exhaust, and a narrow pipe tapped into this feeds directly into the air intake just before the carby. Instant and constant carb heat. Simplle and fail-proof. What power loss? Have no idea.

Duncan
 

TiPi

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Carb icing and the evaporation are 2 separate problems linked by the temperature of the intake air:
- carb icing can happen at the butterfly even with a warm manifold if the carburetor is isolated from the manifold
- fuel evaporation is helped by air temperature from the time the fuel enters the airstream
- it is better to have the carburetor isolated from the manifold to reduce heat-soaking after shutdown to prevent hot-start issues

Carb icing and fuel evaporation benefit from an increase in air temperature entering the carburetor. The downside is the powerloss due to decreased air density and the added mixture change (richer) as the temperature increases.

Ideally, at WOT the air temp is as cold as possible and then increases to about 25-30deg C with closing trottle, and 50-60deg at idle to help with the fuel evaporation at low air volume and velocity. Carburetted cars used to have a thermo vacuum valve that controlled the intake air temp regardless of throttle position.
1594852440102.png
 

Hephaestus

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Got some excess battery power?

Diesels have intake air heaters...fuel-systems-dih1-64_1000.jpg

Warm air no recirculation, just takes amps. Would be fairly easy to build a fancy driver to have it come on as needed without input.
 

Hot Wings

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Noticed something quite disturbing last night. I was scanning the usual sources here in the US for the 810 engine we are both working on to check the current price trends.

Seems like the 810 may be history. Only one source has any listed (EFI version) and even the B+S site says they are "out of stock". Given the Pandemic this alone wouldn't be all that concerning. In place of the usual selection of 810 versions I see series 61s (Big Blocks) that have mounts for both vertical and horizontal mounting.
If I were a company in the same financial condition a new universal engine would be something I'd consider. It would be nice to have a 1L class engine to convert.....

Unfortunately for us weight isn't much of a concern for lawn mowers. Also the 61's all have internal oil pumps meaning that a bolt on conversion to inverted is going to be nearly impossible.
I still want a converted 810 for personal use but it looks like it's days for a commercial product may have come to an end? :grave: :beer:
 

Vigilant1

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I dunno. Yes, I saw looked around and saw a lot of the normal retailers were short on 49 series engines. OTOH, Small Engine Warehouse seemed to still have a wide selection of 49 series engines, and quite a few in stock (e.g they show 88 of these EFI engines with 1 1/8" shafts are in stock).

There are many strong companies with good balance sheets that cut back production a lot due the uncertainty of this COVID issue, they just wanted to reduce production to stay liquid long enough to emerge in good shape. There are lots of stories of shortages at Home Depot and Lowes of lumber, plywood, etc due to this. I imagine the situation could be a lot more severe at B&S due to the precarious financial situation of the company.

I'd think the local newspaper(s) where the 810cc plant is located would have stories about it if the line had been shut down or was being retooled. I'll poke around a bit on that...
 

TiPi

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Thanks for the update. I know that they have delivery issues, I have a short-block on order with a lead time of 3-4 months. Hopefully there are enough OEM users of the 810 (and 40/44-series engines) out there to pull it through.
Otherwise Hot Wings and myself will have some unique engines :( I have all the parts to finish mine but I don't have the forged crank yet.
I haven't found any news other than the chapter 11 announcement.

Then again, this is not a nice picture, looks like the Swiss Alps are heading to the Mediterranean (or the Rockies to the Pacific):
1598140707505.png
 

WonderousMountain

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So now that you're a V-twin expert,
How about those Honda Aviation style heads?
Any chance we could reconfigure the parts
Into a flat twin?¿?
 
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Vigilant1

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The 810cc engines are made in Auburn, Alabama. The town has two newspapers (plus the student newspaper for Auburn University).
-- There wasn't anything in the Opelika-Auburn News, just some boilerplate from the B&S management about the importance of the factory (like this).
-- I couldn't find anything in The Auburn Villager that seemed pertinent.
Maybe calls to some of the retailers regarding the supply situation would yield some information.

I would think the commercial engines have more profit margin than the semi-disposable consumer-grade singles. And, given the cash-strapped situation they are in, I'd think that re-tooling for a new universal engine would be out of the question. But I don't know anything about this business and it may not be reasonable to assume the B&S managers (old or new) will act rationally.
 

Hot Wings

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Hopefully there are enough OEM users of the 810 (and 40/44-series engines) out there to pull it through.
There still seems to be plenty of the 44's out there - and I somehow missed the Small Engine Warehouse site. I hope I'm just being pessimistic but I can understand the logic of jumping from the 44 to the 61 and discontinuing the 49. I wonder if there is enough material in the 44 block casting to bore and sleeve for the 49 pistons?

I started seeing how a little turbo would work and discovered that the price here in the US for the little RHB31 clone is about half what it was a year ago. Rotax uses a separate mechanical scavenge pump on the their turbo versions. this would add complications but I think there may be a way to scavenge the turbo with the flow from the crankcase to the oil sump.
810 turbo.JPG

Did some thinking about motor mounts on the flywheel side. How about using the head bolts for the mounts?
810 flywheel mounts.JPG

I'd think that re-tooling for a new universal engine would be out of the question.
It looks like they already have a "universal" 61 series block in production. I haven't researched it enough to tell if it is truly universal or if it just has mounts for both the vertical and horizontal shaft. It think it would be a pretty simple thing to locate the internal oil pickup so that it worked for both if that was part of the original plan.
Thanks for the feedback! If you hear anything related to the 810/49 please let us know.
 

pictsidhe

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The 61 is much heavier and more expensive than the Intek 4x engines. If they are going to drop a model, the smaller ones seem more likely. They can easily strangle an 810 to lower power.

I am worried enough about the future availability of the 810 that I am looking for an alternative. There are a few Chinese manufacturers of 764cc engines that might be worth a look. They seem heavy, though. I have asked for long block weights.

It's possible that somebody would buy up things like the small and large block Briggs vanguard designs. The 810s don't have their reputation, though.
 

Hot Wings

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I am worried enough about the future availability of the 810 that I am looking for an alternative.
I'm a little less worried than I was when I posted about the apparent supply problem. I too have been keeping an eye out for an alternate but so far there just doesn't seem to be much. The next step down in displacement just isn't going to provide the power that is needed (IMHO) for even the small light aircraft we are thinking about. The 1L class are significantly heavier.

If I didn't want to use direct drive in an inverted configuration I'd just move to the 1L class and take the weight hit.
 

TiPi

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If B&S drop the 49, then they will also drop the 40 and 44 as they all use the same heads and pretty much the same block, crank and all other gear (just different bore & piston and some minor items). That's why I'm quite confident that this series of engines will stay. There are lots of mowers out there with 40, 44 and 49 engines.
I have a need for a new mower, what suits my needs is the Cub Cadet RTZ S 46. Unfortunately, it only comes with a Kohler 7000-series (23hp, 725cm3). They have lost a bit of weight, listed as 38.6kg dry (725-750cm3). 30-32hp would be about the max as direct drive.
The next size up (824cm3, 29-33hp) is again far too heavy at 61kg dry (they will shed more weight with the big air filters and intake plumbing).
 

Vigilant1

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I too have been keeping an eye out for an alternate but so far there just doesn't seem to be much. The next step down in displacement just isn't going to provide the power that is needed (IMHO) for even the small light aircraft we are thinking about. The 1L class are significantly heavier.
Agree. The 28-30 HP using direct drive is enough for the project I'd like to build, and the HP/lb is more attractive than smaller or larger twins. The fact that new ones sell for a good bit less than a smaller horiz shaft engine is a pleasant plus. If they sold a horiz shaft 810cc engine, it would be interesting to see where the market would price it.
 
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Hot Wings

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(just different bore & piston and some minor items). That's why I'm quite confident that this series of engines will stay
I have no doubt the series will still be produced, but if I were in the position of B+S management I could see a pretty strong case for dropping 2 of the sizes. Every part number or variation they can get rid of makes the production cheaper, along with reducing the repair part numbers stocked.

If they can get by in the HZ market without an 800cc class twin then maybe the end users in the vertical market can get by with a single V-twin between the single cylinder engines and the big block twin?

I know the commercial mower market is a very competitive one (note the dry sump series that exists solely to reduce oil change labor and down time) but I can't see needing the efficiency advantage offered by using an 40 cu in engine rather than a 49. Maybe if we are lucky they will drop the smaller ones and just make the 49's. That would be good for us.

The Predator (Harbor Freight) vertical has an external oil pump but it is 100cc less and who knows what the future of Chinese imports will be here in the US.
 

Vigilant1

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Some notes:
- 49 Series future: As an update from August, I still couldn't find anything indicating B&S plans to discontinue the 810cc engines. A quick review of the local press near the Auburn, AL plant that manufactures the 810cc engines didn't have any news about cuts. The number of engines on the shelves at retailers seems to be good (e.g. Small Engine Warehouse has 75 of the Vanguard 49E877-0002 engines in stock today. In August they had 88, so a slight drop, but that may be entirely normal). It is worth keeping an eye on this, but there doesn't seem to be any current/impending closure of 49-series production.
- I'm looking around at used B&S V-twins to be used as testbeds/learning aids, and there aren't many 49 series engines out there. On the other hand, there are >tons< of used 44 series (724cc) engines -- Intek, Pro series, etc from 22-27 HP (by B&S "gross HP" method--snicker). B&S doesn't make a Vanguard version of the series 44 engine, but the others are there in droves. It is no trouble to find several for sale nearby, ostensibly in running condition, priced at about $200 each (complete with a thrashed riding mower to be taken by the scrapper). It's the same situation on the showroom floor--lots of the 44 series on mass market residential grade riding mowers (at Lowes, Home Depot, etc) , but the 49 series are generally found on higher-end commercial grade mowers in the commercial lawn equipment stores. I'll bet B&S sells four of the 44 series engine for every 49 series engine they sell (but they probably net quite a bit more on each of the 49's) .
The 44 has the same 2.89" stroke as the 49, but the bore is smaller (3.12" vs 3.3")
So, even if I will eventually want a Vanguard 49 series engine to put in a plane, I'm leaning toward getting a used 44 series engine (or two) to take apart and run as a test mule. Any opinions? There are some common parts between the Vanguard 49s and the Commercial 44s, so the 44s could also be a source of spares. (Common parts include the magnetrons, oil pump, oil filer adapter, oil cooler adapter, the fan, alternator coils, etc.) The flywheel (and puller) is the same on the 44 series engine and the 49 series "commercial" engines, but the flywheel model number is different for the Vanguard 49 series. Any ideas on how the Vanguard flywheel might differ? Similarly, the cylinder heads, valves etc are the same between the commercial series 44 and commercial series 49 engines, but the Vanguard 49 series engines have different heads, valves, etc (Tipi noted that the Vanguard valves are beefier).
IIRC, pictsidhe has a B&S V-twin that is a little smaller than the 49 series--maybe a 44?
 
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pictsidhe

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I picked up an intek 40 for very little. It had thrown a rod, but is perfect as a mock-up and experimental engine. May well use the heads on a 49. It has smaller valves. With some porting, it should be capable of more torque than the bigger valve head on the 49. The ports are horrific, Briggs compensated with size
 

blane.c

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Because the pistons are smaller and presumably lighter on the "44" vs. the "49" do the crankshafts and/or flywheels differ for balance reasons?

Are the Intek 40 heads a close fit for the 49? Or how much modification do you foresee? Are they lighter heads? Is the cooling area similar?
 
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