Open cowling versus pressure cowling

[Kaiser]

I'm looking at a possible trade for 1940 Taylorcraft that was restored less than 10 years ago and the Lycoming engine replaced with a 65 Continental. The builder used an open cowl to house the engine. Are there any advantages or disadvantages to this design; for I would expect some cruise speed reduction, but what is to be expected? This particular aircraft has the big round control wheels and one 6 gallon wing tank, in addition to the standard 12 gal. I have not had a chance to inspect the aircraft as of yet, but would appreciate any input as to what particular original items to look for in this year model (it does not have the big RPM/engine gauge). The engine has about 460smoh and the pictures I received shows a complete rebuild of the airframe from the ground up. Thanks in advance, Kaiser.

[Hank Jarrett]

Re: Open cowling versus pressure cowling

We need to hear from some of the IAs here. I know we have been told changing from a Lyc to a Continental is fairly easy with the FAA but I don't think it is that simple for going from exposed cylinders to closed cowl (the Taylorcraft closed cowl is not really a "Pressure Cowl, but there are a few guys in the group who have made pressure cowls, they work great, but are not as simple and changing the cowl). I don't have an open cowl plane to compare but isn't the boot cowl and fuselage frame in the nose also different? Sure looks like it in the factory photos!
If the restorer has reconfigured the plane you need to see exactly what has been changed and if it was done correctly. It could have a significant impact on the value.
The instrument panel with the wrong instruments is also a question, but I don't think that serious from all the pre-war planes with post war panels in them. Might be one of those cases where the FAA doesn't even know what they are looking at or putting a later panel in an early plane isn't an issue. Again, IA's? I could talk to the safety, but what about the regs?

Hank

[3Dreaming]

Re: Open cowling versus pressure cowling

The open cowl will not hurt the speed as much as you might think. The biggest problem with speed is the trim will not let trim nose down far enough to get the higher speed that you might want. I have done the conversion from the 65 Lycoming to the 65 Continental, and it is not a big deal. Make sure that there is the proper paperwork to go along with the engine change. Also check the paperwork for the wing tank. There is a note where it can be added under TCDS A-696, but the BL was built under TCDS A-700, and it doesn't have that note. The instrument panel can always be changed back to original, if you can find the parts. Paperwork for what has been changed shouldn't be to bad to take care of if it wasn't done right to begin with.

[Kaiser]

Re: Open cowling versus pressure cowling

Hank and 3D, thanks for the information. Kaiser

[astjp2]

Re: Open cowling versus pressure cowling

If you never wreck the airplane, the FAA will never look or know either! grin