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brian]
Cleared for Takeoff
Found on a post found here - sorry, not sure if it is a public site, but I keep stumbling upon it - excellent information:
www.matronics.com / archive / archive-get.cgi?Beech-Archive.digest.vol-ad
I think you will find that the group on this email list will have no problem agreeing that the early series Bonanzas are the nicest handling, least expensive, and most fun of the Bonanza line, if not the fastest. The E-series engine has its faults, but if you are nice to it (and feed it lots of oil), you will be rewarded with long and dependable service.
The Beech Bonanza propellers are an interesting story and I hope I can tell some
of it correctly.
When the Bonanza was being developed, Walter Beech wanted the best performance possible from a new engine developing about 165 hp., so he had to go to a constant speed prop to do it. Beech had been using the Curtis design electrically controllable pitch propellers with good success on its war models, and it was adapted for the new Bonanza. A small electric motor changes the pitch of the propeller blades (instead of hydraulic pressure from motor oil, regulated by a pressure governor). The electric pitch motor is controlled by an up/down toggle in the cockpit.
The first was the R200 series wooden propeller. The prop pitch change motor is mounted quite a ways back, and has a long drive shaft that engages the ring gear that changes the blades' pitch. Legend has it that this was the most efficient propeller ever made for the Bonanza. These are only used on the model 35 and A35. The blades were BIG. 88" in diameter. Wide. 11" across, I think. A note here -- the electric pitch change mechanism was NOT a "constant speed prop." it was an "electrically adjustable prop." The engine's rpm will drift over time, meaning that you had to manually ajdust the pitch using an up/down toggle switch to maintain the same rpms. YOU were the constant speed governor.
Beech did introduce an electronic pitch governor unit, and it *did* make the system a constant speed prop, but it was an option that cost more money. Something like $495 back in the 50's, if I remember correctly. Not everyone coughed up the extra dough. The original Beech electric prop governor unit made by Flight Research (not THAT Flight Research) is a cantankerous marvel, using vacuum tubes and light sensors to maintain the propeller's rpm. The system is tricky to repair, and, like everything else, the parts are hard to find. Airborne Electronics, a company in N. Calif., came out with a solid state electronic governor unit that replaces the original one, and is a zillion times more reliable. (I have it and it is brainless to install and use.)
The next series was the B200. The electric motor that changes the props' pitch is mounted right next to the ring gear, and the hub is beefed up a bit, larger blade bearings were used, and there were some other changes. The engine that Beech used wasn't 165 hp. after all. It was a 185 hp. E185-8 (ad later, the E185-11) engine. Still used the same birchwood propeller blades, though. I think the wooden blades are subject to a 100 hr. repetitive AD forcing them to essentially be refinished every 100 hours. (Correct me, guys, if I am in error here). So, even though getting replacement wooden blades would probably be relatively easy (just have a new set made), the AD makes them very expensive to maintain.
In 1954, Beech offered a new beefier engine -- the E225-8. The fancy new 215 series propeller came out, to go with it, and had the same electric prop pitch change system, but with a few improvements. The blades are the biggie. They were aluminum. Still 88" long, but something like 8" wide. The aluminum blades were such a hit that they also became usable on the B200 series hubs, but not the R200. The aluminum blades are *NOT* as efficient as the original wooden ones, but only by something like 1%, so the experts say. With the new E225-8 engine, you could use 2600 rpm on takeoff (for one minute), and at that speed, the 88" prop was getting pretty close to the speed of sound. A recommendation was made to trim the blades from 88" to 84", reducing the tips' speed enough so it didn't scream so much. Earlier takeoff limits were, I think, 2300 rpm, so this was a BIG improvement for the ever-heavier airplanes and their payloads.
Beech made changes to the type certificate so you could retrofit the aluminum blades on earlier models if you wanted, and practically everyone did. 88" aluminum blades for the E185-11 engine, and 84" blades for the E225-8 engine. (A little empirical data here -- My 1954 E225-8 powered E35 Bonanza originally had the 84" blades on it, and I had to have 'em replaced. Found an 88" set, and put them on without trimming them. I can do that with the E35 model. My data showed that the additional 4" of prop disc gives me about 2 kts higher speed. So there's another 1-1/2% loss most of the planes suffer)
In 1957, Beech changed the engine (again) from the E225 series to the IO-470 series. This engine has the hollow crankshaft capable of using a hydraulically controlled propeller pitch mechanism, so they discontinued the Beech electric propeller, developed the Beech 278 series prop for the Hartzell controller. Unsubstianted claims state that the 278 series propeller loses, again, about 1-2% efficiency over the previous (215-series) blades. But, since there was a more powerful 260 hp. engine, nobody cared. Hartzell also developed a hydraulic pitch governor for a set of Hartzell blades which was a direct swap for the Beech B200 / R200 / 215 series propellers, so those that wanted nice, smooth, trouble-free constant pitch could have it. So, lots of people switched to the Hartzell blades/governor, and they were in ignorant bliss until a few years ago when the onerous AD came out requiring a mandatory 5,000 hr. (or X years?) inspection. Lots of folks found out that their props were in poor shape (Surprise! See what 0 maintenance over 10 years will do?). Once the AD is complied with, the Hartzell is again trouble-free and you won't have to give it another thought.
HOWEVER, The Hartzell conversion is a nightmare of parts that are different from a "normal" hydraulic prop system, and the installation guides are, in some places, vague. In other places, they are incorrect. Who knows how many units were damaged by inexperienced mechanics? If you have this system, you NEED to get the back issues of ABS magazine, and read, nay, memorize all of Lew Gage's "Currents" columns dealing with the Hartzell propeller installation and service. The Beech electric props, on the other hand, have never had an AD against them, although the recommended service time is a removal and inspection every 250 hours, and an overhaul every 1,000 hours. The big bugaboo is parts availability. Beech 84" and 88" 215-series blades are very hard to find. Something like $4,000 if you do. The little electric prop pitch motor that looks like it comes out of a SkilSaw costs something like $400 to overhaul. The pitch change bearing is unique, and replacement cost for this little devil is over $1,000 -- when you can find it. So, like so many other brilliantly-engineered wonders, the Beech electric prop is slowly fading away mainly due to lack of parts, not poor performance.
www.matronics.com / archive / archive-get.cgi?Beech-Archive.digest.vol-ad
I think you will find that the group on this email list will have no problem agreeing that the early series Bonanzas are the nicest handling, least expensive, and most fun of the Bonanza line, if not the fastest. The E-series engine has its faults, but if you are nice to it (and feed it lots of oil), you will be rewarded with long and dependable service.
The Beech Bonanza propellers are an interesting story and I hope I can tell some
of it correctly.
When the Bonanza was being developed, Walter Beech wanted the best performance possible from a new engine developing about 165 hp., so he had to go to a constant speed prop to do it. Beech had been using the Curtis design electrically controllable pitch propellers with good success on its war models, and it was adapted for the new Bonanza. A small electric motor changes the pitch of the propeller blades (instead of hydraulic pressure from motor oil, regulated by a pressure governor). The electric pitch motor is controlled by an up/down toggle in the cockpit.
The first was the R200 series wooden propeller. The prop pitch change motor is mounted quite a ways back, and has a long drive shaft that engages the ring gear that changes the blades' pitch. Legend has it that this was the most efficient propeller ever made for the Bonanza. These are only used on the model 35 and A35. The blades were BIG. 88" in diameter. Wide. 11" across, I think. A note here -- the electric pitch change mechanism was NOT a "constant speed prop." it was an "electrically adjustable prop." The engine's rpm will drift over time, meaning that you had to manually ajdust the pitch using an up/down toggle switch to maintain the same rpms. YOU were the constant speed governor.
Beech did introduce an electronic pitch governor unit, and it *did* make the system a constant speed prop, but it was an option that cost more money. Something like $495 back in the 50's, if I remember correctly. Not everyone coughed up the extra dough. The original Beech electric prop governor unit made by Flight Research (not THAT Flight Research) is a cantankerous marvel, using vacuum tubes and light sensors to maintain the propeller's rpm. The system is tricky to repair, and, like everything else, the parts are hard to find. Airborne Electronics, a company in N. Calif., came out with a solid state electronic governor unit that replaces the original one, and is a zillion times more reliable. (I have it and it is brainless to install and use.)
The next series was the B200. The electric motor that changes the props' pitch is mounted right next to the ring gear, and the hub is beefed up a bit, larger blade bearings were used, and there were some other changes. The engine that Beech used wasn't 165 hp. after all. It was a 185 hp. E185-8 (ad later, the E185-11) engine. Still used the same birchwood propeller blades, though. I think the wooden blades are subject to a 100 hr. repetitive AD forcing them to essentially be refinished every 100 hours. (Correct me, guys, if I am in error here). So, even though getting replacement wooden blades would probably be relatively easy (just have a new set made), the AD makes them very expensive to maintain.
In 1954, Beech offered a new beefier engine -- the E225-8. The fancy new 215 series propeller came out, to go with it, and had the same electric prop pitch change system, but with a few improvements. The blades are the biggie. They were aluminum. Still 88" long, but something like 8" wide. The aluminum blades were such a hit that they also became usable on the B200 series hubs, but not the R200. The aluminum blades are *NOT* as efficient as the original wooden ones, but only by something like 1%, so the experts say. With the new E225-8 engine, you could use 2600 rpm on takeoff (for one minute), and at that speed, the 88" prop was getting pretty close to the speed of sound. A recommendation was made to trim the blades from 88" to 84", reducing the tips' speed enough so it didn't scream so much. Earlier takeoff limits were, I think, 2300 rpm, so this was a BIG improvement for the ever-heavier airplanes and their payloads.
Beech made changes to the type certificate so you could retrofit the aluminum blades on earlier models if you wanted, and practically everyone did. 88" aluminum blades for the E185-11 engine, and 84" blades for the E225-8 engine. (A little empirical data here -- My 1954 E225-8 powered E35 Bonanza originally had the 84" blades on it, and I had to have 'em replaced. Found an 88" set, and put them on without trimming them. I can do that with the E35 model. My data showed that the additional 4" of prop disc gives me about 2 kts higher speed. So there's another 1-1/2% loss most of the planes suffer)
In 1957, Beech changed the engine (again) from the E225 series to the IO-470 series. This engine has the hollow crankshaft capable of using a hydraulically controlled propeller pitch mechanism, so they discontinued the Beech electric propeller, developed the Beech 278 series prop for the Hartzell controller. Unsubstianted claims state that the 278 series propeller loses, again, about 1-2% efficiency over the previous (215-series) blades. But, since there was a more powerful 260 hp. engine, nobody cared. Hartzell also developed a hydraulic pitch governor for a set of Hartzell blades which was a direct swap for the Beech B200 / R200 / 215 series propellers, so those that wanted nice, smooth, trouble-free constant pitch could have it. So, lots of people switched to the Hartzell blades/governor, and they were in ignorant bliss until a few years ago when the onerous AD came out requiring a mandatory 5,000 hr. (or X years?) inspection. Lots of folks found out that their props were in poor shape (Surprise! See what 0 maintenance over 10 years will do?). Once the AD is complied with, the Hartzell is again trouble-free and you won't have to give it another thought.
HOWEVER, The Hartzell conversion is a nightmare of parts that are different from a "normal" hydraulic prop system, and the installation guides are, in some places, vague. In other places, they are incorrect. Who knows how many units were damaged by inexperienced mechanics? If you have this system, you NEED to get the back issues of ABS magazine, and read, nay, memorize all of Lew Gage's "Currents" columns dealing with the Hartzell propeller installation and service. The Beech electric props, on the other hand, have never had an AD against them, although the recommended service time is a removal and inspection every 250 hours, and an overhaul every 1,000 hours. The big bugaboo is parts availability. Beech 84" and 88" 215-series blades are very hard to find. Something like $4,000 if you do. The little electric prop pitch motor that looks like it comes out of a SkilSaw costs something like $400 to overhaul. The pitch change bearing is unique, and replacement cost for this little devil is over $1,000 -- when you can find it. So, like so many other brilliantly-engineered wonders, the Beech electric prop is slowly fading away mainly due to lack of parts, not poor performance.
