Dynamo

Choosing which type of dynamo to use and where it is located impacts a range of other plumbing and other elements in the firewall forward part of the build.

Front Mounted

WilliamWynne encourages Corvair builders to use the simplest approach for their dynamo setup, which is a front-mounted John Deere (JD) 20 amp unit. He has weighed the parts for shipping and posted the weights and provided additional information about sourcing an appropriate unit. For installations with a FifthBearing, a front starter and a front JD alternator can have a simple one-hose oil system. Note, the STOL 750 will need a larger oil cooler and will preclude the one-hose system.

Weights:

• John Deere 20 amp alternator 3 pounds, 11.5 oz.
• WW front alternator bracket 0 pounds 13.3 oz.
• Drive belt 0 pounds 1.6 oz.

WW says that the JD 20 amp unit provides enough power for virtually every Corvair powered plane flying that he's seen and that the 20 amp unit is sufficient to address power demand peaks as most loads are intermittent while providing the lightest solution by several pounds. They also have outstanding reliability, mostly because they don't have brushes or contacts inside.The downside to the John Deere part is that they can cost as much as $335 due to their branded nature. The identical part can be obtained from Yanmar dealers for $138 from Hoye tractor parts. (See under external links below.) Buyers are cautioned to read OrderingFromNonAviationSuppliers before asking for an aviation part from a tractor shop. Wynne recommends ordering it online and says he has received good service from them.

Rear Mounted

An alternate setup is a rear-mounted setup using the Denso teacup alternator, with internal regulator. The Denso teacup alternator weighs 6 pounds 2.0 oz; the brackets are similar in weight, but it would need a small pulley, making the weight difference about three pounds in favor of the front-mounted setup. With the Denso on the back, it is often necessary to have a remote OilCooler. This involves lines and a scat hose to the new cooler location and could cost an additional $100 in parts and 1-1.5 pounds in weight over the front mounted setup. Because of its slow speeds and reduced airflow in steep climbs, the STOL 750 needs a larger oil cooler, requiring the two hose system, plus a fifth bearing line. A firewall location has been used for the remote oil cooler.

Related terms

OilCooler, VBelt, AlternatorBracket

External links

Hoye Tractors - Yanmar 20 amp JD replacement unit. It is part # 124190-77201

Patrick Hoyt's site