BPE-14 Turbo Alternator

Aircraft electrical systems. Generators, both engine and wind driven. Other electrical systems, wiring, fuses, lighting and so on.
jepropst
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Re: BPE-14 Turbo Alternator

Post by jepropst » Sun Mar 24, 2013 14:43

I wanted to provide an update to this thread. I have just installed a BPE 14 alternator on my Champ. So far, with a limited number of flights, I have been very pleased with the performance of the unit. Based on some of the comments in this thread, I contacted the manufacturer with a number of questions including the performance problems due to the lip on the wraparound. The owner of the company, Ron Cox, responded quickly to my email questions with answers to all my questions, including the concern related to the performance. Over the course of a couple weeks we had a number of communications via email and I was very pleased with the prompt and factual response. Ron discussed several installations on Champs and Chiefs and sent pictures and drawings of methods used to improve the output. I also called Bill Pancake and discussed the installation. Bill had been involved with several installations of the unit and offered several suggestions similar to the ones that Ron had provided. Bill and I ruled out moving the unit to the left landing leg because it would involve a field approval for deviation from the STC. I felt we should first install it in accordance with the STC and see how it worked. I ordered the unit directly from Ron rather than going through a vendor such as ACS. Ron paints the units to any color on the Polyfiber paint chart. The unit arrived in very good condition and matched my plane perfectly. I initially installed the unit with no modification of the lip on the wrap around and the alternator output seemed limited, which did not surprise me. I do have a Concorde battery permanently installed behind the back seat but I do not have a great deal of running load, so I am limited to how much I can load the alternator. Following the initial tests I fabricated a “tab” and attached it to the wrap around lip as shown on the photo. I also fabricated three miniature vortex generators for the tab. I’m not sure if they added anything to the performance but I figured it wouldn’t hurt. Adding the tab definitely improved the performance. On the last flight the battery voltage was around 11.5 volts prior to starting the engine with the electric starter. At about 1500 rpm the alternator begins providing output current. After takeoff and over the next six minutes the voltage on the Concorde RG 25XC battery steadily increased from 11.5 volts to about 13.5 volts. The peak current output that I saw on the alternator output ammeter was about 6.5 amps. Other than the battery, the only load that I have on the alternator is a 296 GPS, an Icom 210 radio, and the master solenoid, so most of the output current was going to the battery. The only undesirable consequence that I have experienced since installing the alternator is that with my com antenna mounted directly in front of the unit, the radio reception is now very directionally sensitive. My plan to address this issue is to move the com antenna to the wing root cover during the upcoming annual.
bpe 14 photo.jpg
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John Propst
313 Hickory Grove Ln
Elizabeth, WV 26143
cell 304 588 3690
j.e.propst@ieee.org
N3129E 2WV3

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Re: BPE-14 Turbo Alternator

Post by joea » Sun Mar 24, 2013 15:34

John,

Looks interesting... how much airspeed did you drop?

A ballpark cost?

Joe A

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Re: BPE-14 Turbo Alternator

Post by jepropst » Sun Mar 24, 2013 15:45

Joe, it's a "turbo" alternator. It makes a Champ go even faster than a Chief.

Seriously, I couldn't tell any difference in speed. My normal speed range varies anywhere from 92 to 105 mph, with the biggest variable being the pilot's skill. I did dive the airspeed north of 120 just to see if the current output would increase, but it didn't.

Cost of the unit is around $800. The engine analyzer already has a voltmeter. I picked up a nice analog ammeter for $12. Everything else came out of the surplus pile.
John Propst
313 Hickory Grove Ln
Elizabeth, WV 26143
cell 304 588 3690
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Re: BPE-14 Turbo Alternator

Post by joea » Sun Mar 24, 2013 19:48

If its faster than a Chief, then it must have JATO rockets on it as well!

Cost is reasonable and with that you are still not in the "generator equipped" catagory on the bird.

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Re: BPE-14 Turbo Alternator

Post by hangerash » Sun Mar 24, 2013 21:25

John,

Thanks for posting your observations. I have been looking at these alternators for some time. Do you have a total weight that was added with its installation?

Richard
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Re: BPE-14 Turbo Alternator

Post by jepropst » Mon Mar 25, 2013 05:17

Weight addition is 4.0 pounds located 3.3" forward of datum (leading edge of wing). Attached is a graph of the battery voltage (green line) and engine rpm (blue line) during my last short flight. This data was captured from the JPI 830 engine analyzer. The rapid increase in rpm is take off. At this point the alternator starts charging the battery and the battery voltage increases to over 13 volts. As the engine rpm is reduced for landing the battery voltage drops to slightly over 12 volts as I taxi to the hangar.
voltage 3-22-13.jpg
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John Propst
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Re: BPE-14 Turbo Alternator

Post by hangerash » Mon Mar 25, 2013 12:12

John,

Neat graph! Have you found the JPM worth the investment? What was that spike (higher output) in the alternator output just before you powered down? Had you increased airspeed in a descent?

Richard in OH
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Re: BPE-14 Turbo Alternator

Post by jepropst » Mon Mar 25, 2013 13:36

Richard,
I think that trying to justify an engine analyzer is somewhat like justifying insurance or kids. With the significant investment in a major overhaul with all new parts, I find it desirable to not only know if something is going wrong but also to know that everything is OK. The analyzer had a number of features that I definitely like and would recommend. First, it has fuel flow analysis built into it and is integrated with the output of the Garmin 296 gps. This provides the user with the quantity of fuel on board, the quantity of fuel burnt, the fuel flow rate in gallons per hour, the aircraft fuel usage rate in gallons per mile, the quantity of fuel required to reach the destination, and the quantity of reserve fuel that will be remaining at the destination. Another feature that the analyzer has is the carb temp. There is a thermocouple in the throat of the carb that measures the actual temp within the carb. Around my part of the country carb icing is quite common in Continental engines, and the probe provides some early warning of possible icing. The analyzer monitors oil pressure and temp. The temp is monitored at the front end of the left oil galley and indicates the oil temp midway through the engine. I have found that this oil temp is a better indication of the actual engine oil temp than the temp typically monitored on the outlet of the oil pump. I now routinely warm up the engine until this temperature is at or above 90 degrees. Sometimes when the front galley temp is at 90, the oil temp from the sump still has not moved off the gauge peg. I found that my old analog tach had quite a bit of hysteresis and sometimes indicated the correct rpm but at other times was off by as much as 200 rpm. The electronic tach is of course very accurate. The unit has a manifold pressure indication that is OK but in my mind I prefer to follow the fuel flow rather than the manifold pressure. Likewise the outside temp is nice to know but not necessary. The analyzer does have a calculated % horsepower which I find useful. Of course there are the more standard CHT EGT temps displayed for all the cylinders and provides a quick indication that everything is OK. Mike Busche of Savvy and EAA has written a number of articles related to the value of engine analyzers that I have found interesting. For example a recent article related to “mag checks” in which Mike recommended that the check be performed at 65% power. On my engine 65% power is somewhere around 2150 rpm and is much higher than the 1500 rpm value that I had been using in the past. Mike also has an interesting article on leaning engines and discourages the lean find feature of most engine analyzers. His simple leaning approach is that all is OK if you just make sure that you do not exceed 400 degree CHT, no matter whether you are on the rich or lean side of peak. Above all this is the ability to install a flash drive in the unit and download the data to a pc or to the internet. I have my unit set to record all the data points every two seconds. This provides useful data for trending engine performance over time. Now, does all this justify the significant cost of the unit? To me it does, but everyone has to set their own priorities.
Concerning the step in the voltage and rpm just prior to my landing, I think you may be right in guessing that the rpm increased due to a decrease in altitude. Almost immediately after the spike I applied carb heat and reduced the throttle in preparation for landing. The output data from the Carb heat probe indicated that the carb temp increased from 18 to 103 degrees over a 3 minute period with an outside air temp of about 24 degrees.
You can review data from my aircraft at the following site: https://www.savvyanalysis.com/my-flight ... 9a86a6535b
John Propst
313 Hickory Grove Ln
Elizabeth, WV 26143
cell 304 588 3690
j.e.propst@ieee.org
N3129E 2WV3

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Re: BPE-14 Turbo Alternator

Post by MikeB » Mon Mar 25, 2013 14:15

Very interesting John..especially for us 'motorheads'. I have a couple of questions regarding your Turbo Alternator, etc. Is there a reason why you went with the BPRE-14 rather than the gear drive B & S unit? Other than maybe as Joe described above it still qualifies as a 'non-electric' (thus no transponder) set-up. I'm running a total loss system with my L16/0200 conversion but looking at some options to charge the battery. As your plane is setup somewhat similiar to mine, what is your empty weight/useful load? I always wonder what other Champs weigh as the EW really goes up once you start adding extra components, engine combinations, mufflers, etc. Mine came in around 950# but I'm a pretty light guy and generally fly alone anyway. Also, interested in the 400 degree statement regarding cylinder head temperature as I thought the Continental manual lists the max at something like 550 degree. Mine will generally run less than 350 degrees and maybe 400 on a hard climb.

I'm considering putting a carb temp gauge (analog) in. Don't like surprises :shock: .

Thanks..

Mike

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Re: BPE-14 Turbo Alternator

Post by jepropst » Mon Mar 25, 2013 17:10

Mike, the primary reason for considering even installing an alternator or generator, even though I have the big Concorde battery, is that my Com radio low end voltage rating is 11.5 volts and over long or extended trips I was concerned that I’d lose my radio on low voltage. The three options I considered were 1) install the existing Ward Generator that I have, 2) install the BPE 14 alternator, or 3) install one of the very nice small engine driven alternators. I ruled out the Ward because of weight, added complexity, and lack of factory support, and I ruled out the engine driven alternator because I wanted to continue to be able to fly in and around some controlled airspaces without a transponder (see FAR Sec. 91.215 (b)(3) for more details). I am still uncertain what complexity the ADS-B 2020 requirements will bring but did not want to work myself into a corner that I could not get out of, if at all possible. There is another small wind powered alternator advertised in ACS, but it does not have an STC and I was encouraged not to pursue seeking a field approval when a suitable STC’d device was available.
My empty weight with the addition of the turbo is 934 pounds with an empty CG of 14.49”. The biggest hit that I’ve taken on gross weight was the addition of the hydraulic brakes along with the 800X6 tires. This modification added about 20 pounds. While I’m a bit concerned about gross weight, I am much more concerned about CG limits. I have an Excel weight and balance spreadsheet for my plane and I’ve run many different scenarios to understand exactly what the loading limitations are with respect to both gross weight and more importantly CG. I am far from being a light guy but I also fly alone most of the time. On a few occasions I have flown with another “big” guy, knowing that I am pushing the gross weight, but still well within the CG limits. I have been told that the “weak link” for my plane with respect to gross weight is the landing gear, so whenever I approach the limits I pay extra attention to land as smoothly as possible. With the C85 and the O-200 conversion takeoffs are never an issue.
The 400 degree reference that I mentioned was from Mike Busch’s article title “Red Box, Red Fin” in the Dec 2012 EAA Sport Aviation Magazine: http://www.sportaviationonline.org/spor ... pg=30#pg28
Another article by Mike that I found interesting is:
http://www.avweb.com/news/maint/182849-1.html
If you go to the “Resources” tab and then look under Mikes Blog, you will find additional interesting tidbits at: https://www.savvymx.com/
John Propst
313 Hickory Grove Ln
Elizabeth, WV 26143
cell 304 588 3690
j.e.propst@ieee.org
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Re: BPE-14 Turbo Alternatorf

Post by hangerash » Mon Mar 25, 2013 17:29

John

Again, great posts. I have followed Mike Bush's webinars on the EAA site for some time and find that I prefer the analyzer investment over the analog steam gage for many of the reasons you cited. I have looked at JPM, EI, and MGL for a solution and haven't made up my mind at this time. I do have a month or so to finalize my decision before I button things up and start flying for the summer.

The wind alternator and being able to avoid the transponder requirement is a plus I had not considered.

Richard
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Re: BPE-14 Turbo Alternator

Post by MikeB » Mon Mar 25, 2013 18:08

Thanks John...Especially liked the last article of Mike's. I think one thing that added weight on My L16 is the 'green house' as I'm quite sure fabric would be a lot lighter. That, the 25 amp Concord battery, Superflite 6, interior, etc. etc. But as you say with the engine conversion takeoff is never a problem and I have the 'no bounce' gear for whatever it's worth. I'm at the forward CG so anything I put in the back is a benefit. Putting 13 gallons of fuel in the nose tank doesn't help any either CG wise but the wing tanks (5 per side) have very little effect other than adding weight.

Mike
"If God had intended man to fly He would have given us more money"

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