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General control line discussion => Open Forum => Topic started by: Ara Dedekian on April 19, 2019, 09:19:38 AM

Title: A mystery plane
Post by: Ara Dedekian on April 19, 2019, 09:19:38 AM

        Can anyone identify this plane? It's hanging on the wall of a men's clothing store in Portland Maine. It was built by the owners father in the middle to late 1930's. It's been refurbished by a local modeler for display. The engine looks to be an Ohlson on ignition.

        Ara
Title: Re: A mystery plane
Post by: Steve Lotz on April 20, 2019, 02:43:45 AM
Tethered Trainer?
Title: Re: A mystery plane
Post by: Gary Dowler on April 20, 2019, 04:16:04 AM
Looks to me like it has 3 leadouts.  When was throttle invented?

Gary
Title: Re: A mystery plane
Post by: Jim Kraft on April 20, 2019, 09:39:36 AM
Ohlsson never had throttles, but did have two speed timers. Some planes back then use a relay to change timing, with a battery in the handle. Others could have used a third line to switch back and forth between the two sets of points in the two speed timer. I think Jim Walker use a relay as shown on the Ohlsson instruction sheet in his Fireballs.
Title: Re: A mystery plane
Post by: FLOYD CARTER on April 20, 2019, 01:16:32 PM
Jim Walker's control line patent (I have a copy) shows the O&R spark timer rigged to a 3rd line, and a spring to pull it back to idle.  That sort of works, but the O&R timer, if loosened enough to permit 3rd line operation, tends to get even looser, and even fall off!  I think it would take some re-design of the stock timer to make that work.  I've seen Walker fly a Fireball using that system.  It worked for him.