Originally Posted by
HI847
Hi David:
Glad you joined. You might remember me. We talked long time ago about my enlarged Tipo 120 from Eureka Aircraft.
Christian,
sure, now I remember your T120. Glad someone undertook such a build. The Tipo scaling project has been a real success I'd say and I'm glad several have now been built in 10, 20, 40, 60 and 120 size!
I kind of get the idea you are explaining. A picture would do even better. Basically you are saying the side exhaust engine is inverted and slightly canted and a bent header is needed to connect to the pipe in the center of the pan. Is such a header available or is it custom made?.
Not quite. It's not the header that's bent. The header used is a standard header (can't say what kind of "reach" is needed but likely "long" as in the Tipo) but the engine is mounted with the cylinder at about 150 degrees CCW so the header is positioned just on the side of the
interior of the fuse where the nose gear is located. Usually when an engine is "over canted" it is done to put a SE engine with its header on the fuse bottom centerline (e.g., Hanno's Calypso configuration). Not so with the Illusion. The header and nose gear retract co-exist in the same "chin" area of the fuse.
The header exit is then roughly at the wing LE junction with the fuse so the pipe and header are coupled partly in the chin of the fuse and partly in the pan of the wing. This is the reason why the pan has a wider angled tunnel area at the LE (see picture below) and a straight tunnel in the middle and TE of the wing. Since the header/pipe junction is slightly off to the side the pipe ends up at a 10 degree angle or so running down the tunnel. However, a normal straight pipe would hit the rear of the tunnel on the side so "bent" pipes were invented (see link below) where the expanding chamber portion of the pipe and the rear "muffled" portion are welded at an angle to allow the rear half of the pipe to ride centered in the tunnel.
Headers can be custom made to any shape and size but bent pipes are more rare. To my knowledge they are only commercially available from Weston UK under the Genesis brand name at the moment:
http://www.westonuk.co.uk/westonuk2_215.htm
Back in the day they were more common.
Hope this helps,
David
P.S. If you're looking for a RE Tipo like classic to build, go for the T825 which has a "dent" in the side of the fuse for the pipe. I think Don just finished molding it. Otherwise, Tipo's and Illusions are much better off with SE engines and pipe under the wing - just my opinion.