Alternator for Franklin 150

G

Gary Brink

New member
In a post earlier Dan mentioned a "Denso" alternator which reminded me that my Frankie 150 hsp still has the original generator and I have added wing tip strobes as well as an encoding altimeter in addition to the radio, GPS, etc. I'm fairly certain that my old generator can't handle the electric load required so I'm interested in opinions as well as getting an education. Any and all thoughts are appreciated.
Gary
 
Maybe you know this already, but you can use the larger 25amp generator on your 150 if you use a 165 engine mount, no STC required. Tom Calvanelli sells alternator conversions with 337 paperwork, but it's a pretty expensive proposition. You can find him by going to barnstormers.com and searching for "Franklin Alternator". He's in Kennesaw, GA. There's lots of good information about a conversion here, although I'm not sure it's the same one: http://hangar9aeroworks.com/Alternator/108Alternator.html.

I hope this helps.
 
Gary, if your engine isnt mounted yet, just have a good welder modify your motor mount to put the small dip where the 25 amp generator goes. I dont know if there ever was a 165 mount made. I think they are all modified 150 mounts. If your engine is allready mounted and you dont want to pull it, then you might want to find out if the Densco will fit without changes. I have also seen a 25 amp gen. with the bottom of the thick band that goes around the middle, ground off enough to fit the stock mount. That just might send an IA around the bend, but it had been on the plane for 20 years. A brand new alternator as opposed to a 50 or 60 year old generator sounds real good but solid state regulators dont have a great reliability record, and they are expensive. It is all some kind of compromise .___Grant.
 
Thanks for the information, Grant. My engine is still hanging on the chain hoist but a new alternator is about $1,000 and I really don't want to spend that kind of money if I can avoid it. I did take my old generator in and had it checked out and the brushes replaced but I'm sure it will not do the job with the extras that I have added. It seems like earlier someone was talking about "beefing up" their old generator to produce more amps. Would this be a possibility or would it still not produce enough power?
Gary
 
Hi Gary,
Years ago, Grant sent me a 337 where a guy had his armature rewound so that it would put out 35 amps. I had that done to an extra generator that I have, but I never installed it or got it approved for installation. I did have it checked, and it did put out 35+ amps at rated RPM. I forgot what the ratio is now, and am too lazy to look at the type certificate. Anyway, the only thing I would worry about is the heat it may be putting out. I would put a bigger blast tube on it.
BTW, I have sufficient output from my 25 amp to run my KX155, ICS, txpr/mode C, nav, panel and strobe lights. I put the landing light on on short final. My pitot heat draws 20 amps initially, than drops to 10 amps draw.

Larry
 
Thanks, Larry. Maybe I was anticipating a problem where none exists. When I total my amperage draw, it is only 12.8 amps without the landing light. I couldn't see any amp rating on the generator but I rarely use my landing light unless it is for visability for other airplanes. How many amps does the original generator on a 14-13 2 put out?
Gary
 
Hi Gary,
According to the Cruisair parts manual, it came with a 25 amp generator, though as Grant has said, and apparently you have found, it also came with a 15 amp generator. Because of my "quest" for more amperage, or a better way to monitor what was happening, I got a field approval to install a Davtron dual shunt meter that indicates voltage and BOTH generator output (a load-meter) and system amperage to(from) the battery (ammeter). It was a lot cheaper than the Electronics International meter too. I say that with reluctance, 'cause EI are the greatest people to work with. Their meter has to be hooked up as EITHER a load-meter or an ammeter.
Interestingly enough, it took 6 months to get the field approval, even though the Davtron meter was PMA for other aircraft. They wouldn't add the Cruisair to their approved model list. EI most probably would. I recall that they did that for Allen Harstine when he asked them to do it for installing an EI digital tach in his 14-13-3.

As a side note for Mike, I recall that the guy who "bumped up" my spare generator to 35 amps actually machined the shaft of a 35 amp generator to fit conform to the shaft in a Delco 1101887 generator (the 25 amp gen. that came with our Franklins).

If enough of us are interested, maybe we could get an STC to modify our generators to do that.?? lhl
 
Larry, I checked my generator and found that it is an 1101877. I am assuming that it is a fifteen amp generator but I'm not sure. Do you or does anyone reading this forum know if it is a fifteen amp generator?
Thanks,
Gary
 
Geez, this getting older stuff is for the birds...though it beats the alternative. Gary, I misread my Delco parts book. The 25 amp generator IS the 1101877. The 1101887 is a 35 amp generator and is used on the E-185 and E-225. My excuse is the type size and poor lighting and ...? So, anyway, you've got as good as it gets under the type certificate. Good luck on a field approval if you want more! Let me know if it works. Larry
 
I stand corrected! This thread got me looking through old parts books and sure enough the 150 Franklin book said Bellancas with engine #12814 and up came with a 25 amp gen. That must mean that the factory put the dip in the motor mount on later Cruisairs. I had always thought that only 165s had the 25 amp and that the factory never originally put 165s in Cruisairs. I also noticed that the 15 amp and 25 amp take different shock absorbers. I ordered 2 absorbers last year, just to have as spares and now I dont know if they will work on my 15 amp gen. Oh Well;___Grant.
 
Gary, I went down to my hanger and measured a motor mount. The rear bar of the mount that interferes with the 25 amp gen is 1 inch thick, and the lowered section is 9/32" lower. It is flat bottomed and 3" wide at the bottom, then tapers (angles?) up so that the top of the opening is 4" wide. If you put your engine on with the 25 amp gen, and without the dip ,it will be right against the mount and probably cause a lot of vibration and maybe crack the accessory case._____Grant.
 
Thanks, Grant. My generator is the 1101877 so it must be 25 amp. I have new motor mounts and do not anticipate any problems as it came with the plane. I have been wrong lots of times, however. :(
Gary
 
You must log in or register to reply here.
Back
Top