Hello.
I was finally able to find, and buy, the correct engine used in the Bell 47 for an APU.
Some may think this sounds odd, a 2 cylinder 3 HP engine, but here it is.
http://saturnsurplus.com/engine/twocyl.htm
If you research the NSN number you will find that this is a good match.
The Bell 47 has a separate engine powered APU ? You sure ? I have never heard of this on the smaller piston powered helicopters. I have heard of it on some of the jet equipt helicopters used for starting and aux power and transmission function.
BTW, not a bad price. Wonder if I could adapt one or more to a generator.
Last edited by n2ize; 10-29-2010 at 03:35 PM.
I keep my 2 feet on the ground, and my head in the twilight zone.
Where did you get the info that the engine was use on the Bell 47, Rudy?Originally Posted by n2ize
Seems possible, but it would depend on whether or not you could couple the engine crankshaft to the generator. 3HP is equal to roughly 2.25 KW, although you're not gonna get the full power out of course.BTW, not a bad price. Wonder if I could adapt one or more to a generator.
All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.
Hello.
Yes, depending on the aircraft they may be equipped with an APU for "Hand Starting".
Even the CH-47 can be "Hand Started" by way of manual hydraulic pumps.
Remember that aircraft normally have very limited battery power, perhaps 30 minutes, so if you want to run things like radios (Tube type) while on the ground awaiting instructions you need something other than the battery.
fixed wing of this era did not need this as they need a runway and as such have at least a semi-improved facility.
A helicopter can land nearly anywhere but is limited on fuel so a 3 HP engine makes sense and being a 2 piston job means it is far quieter than a single.
He isn't implying that the 2 cylinder was used for powering the main rotor and tail rotor in flight. On the Bell 37 that is generally handled by a Lycoming 200-300 Hp engine. he's implying that it is used to power the APU. But, I have never seen one on a Bell 47...unless it was retrofitted perhaps which I have never seen. Now, I'll admit, I've only been up close to about 2 bell 47's so maybe I didn't notice is.
yeah, just wondering how it would compare to the typical single cylinder Tecumseh or Briggs & Stratton driving a generator.Seems possible, but it would depend on whether or not you could couple the engine crankshaft to the generator. 3HP is equal to roughly 2.25 KW, although you're not gonna get the full power out of course.
I keep my 2 feet on the ground, and my head in the twilight zone.
I realized that. I mean, it's pretty obvious that it takes more than 2HP to power a helicopter. I just wondered where he got the information that the engine was used on the Bell 47 at all. It says nothing of the sort on the linked Web page.
Better, for sure. Two cylinders is nice--one power pulse for every crankshaft revolution, for one thing.yeah, just wondering how it would compare to the typical single cylinder Tecumseh or Briggs & Stratton driving a generator.
All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.
How are you defining "hand starting" for a full sized heli ? For a jet or piston MODEL RC heli it would mean hand cranking something directly or indirectly attached to the motor crankshaft or turbine in order to start the motor... But even most modern RC heli's use some sort of automated electric start if they are piston or jet powered. Only diff is the electronics and FADEC are usually powered direct from a battery where as on a full size they are using a generator/magneto.
Right... which is where a magneto comes in. I've just never heard of a separate engine powered unit on any of the Bell 47 series. I don;t see it listed in any of the parts lists.Even the CH-47 can be "Hand Started" by way of manual hydraulic pumps.
Remember that aircraft normally have very limited battery power, perhaps 30 minutes, so if you want to run things like radios (Tube type) while on the ground awaiting instructions you need something other than the battery.
http://bell47parts.com/PartsList.aspx
And yet they generally have a magneto to provide power to the electronics, accesories, charging batteries, etc.fixed wing of this era did not need this as they need a runway and as such have at least a semi-improved facility.
huh ? But the helicopter is not running on a 3hp engine. It is not going to provide anywhere near enough power for lift and flight.A helicopter can land nearly anywhere but is limited on fuel so a 3 HP engine makes sense and being a 2 piston job means it is far quieter than a single.
Some of the newer helicopters, like the Bell 407 are relatively quiet but that has a lot to do with new main rotor designs, rotor head speeds, etc. takeoff and landing area don;t mean squat. true a heli can take of and land vertically because the rotor is constantly spinning and generating enough lift regardless of the actual forward speed of the aircraft (although forward speed will impact lift at a given pitch). A fixed wing needs forward speed for lift. But in either case its coming from an engine... jet or piston... that is a lot bigger than 3 Hp.
Last edited by n2ize; 10-29-2010 at 06:40 PM.
I keep my 2 feet on the ground, and my head in the twilight zone.
Hello.
APU.
http://en.wikipedia.org/wiki/Auxiliary_power_unit
The only thing it is used for is running equipment on the ground while the engine is off and to assist in starting.
You can not easily crank the main rotor of a helicopter as you can spin the prop of a fixed wing by hand.
However you can wrap a rope around the front spindle of that small engine and pull.
And this means of starting was quite common in the era that the Bell 47 came out in.
http://www.tractorbynet.com/forums/g...ony-motor.html
Batteries were not as compact as today nor as reliable and the electrical load of tube type radios just on receive was something to deal with.
And remember we a talking VHF here, at least a dozen tubes plus vibrator.
If the aircraft was equipped with another radio simply double the current.
Remember that a helicopter was used as a scout and so radio contact with both the ground and other aircraft was vital.
Just like tractors no longer you pony motors but simply better batteries and starters as a rule, most aircraft no longer have the small engines but good batteries and solid state radios.
But if you want to hand start a helicopter this is just about the only way.
Rudy, I know what an APU is and the other link you provided was all about farm tractors, not helicopters. I'm not saying that the little motor you bought isn't from a Bell 47--I honestly don't know--I was only asking you from where you got the information that it is.
All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.
Farm tractors, helicopters, they are both the same thing. They both are used outside and have a loud motor.
"Friendships come in strange packages
The best ones are opened with a smile"
NA4BH '15
Posting Permissions
Reply With Quote