bdon661
New member
Early this morning, I had a conference call with the German engineer at MT Prop, the DER handling the approval, and the 'AOC'. I have no idea what an AOC is, other than to say it is the FAA guy handling the application.
The call went very well. The application has been worded to apply to either the 150hp or 165hp Franklin on the 14-13 series airplane. The final verbiage will be along the lines of "Franklin 6A-series engines as enumerated on the aircraft TCDS". In other words, guys with EITHER 150hp or 165hp Franklin-powered airplanes will be able to use my 337 as approved data. The caveat will be that the low pitch stops of the prop will have to be set to accommodate the maximum RPM of the respective engines - something that can be done in the field by a qualified A&P.
The AOC and DER agreed there were no technical issues with approval and, barring any schedule or review issues, I should have my field approval within six weeks.
The engineer at MT is running some numbers to see which blade profile - classic or scimitar - would work best for this installation. In the interest of keeping an original appearance, my preference is for the classic blade profile, but if there is a significant performance benefit of using the scimitar blades, I will use them. MT will finish the prop in any color I want and I'm on the fence about black blades to match the appearance of the Aeromatic or white blades with red tips to match the airplane's paint scheme. I went with white blades / red tips / red decals with the Aeromatic on my red Fairchild and it looks AMAZING - so we'll see. The profile of the new spinner that comes with the prop will match the profile of the factory spinner.
If the prop is done before the 165hp engine, I'll install it on the existing 150hp engine so I can have an 'apples to apples' comparison regarding performance improvements. Regardless of which engine is on the airplane at the time, I'll share my performance results with the group, along with a copy of the approved 337 and any other pertinent data.
Best Wishes,
Brad Donner
NC86916
The call went very well. The application has been worded to apply to either the 150hp or 165hp Franklin on the 14-13 series airplane. The final verbiage will be along the lines of "Franklin 6A-series engines as enumerated on the aircraft TCDS". In other words, guys with EITHER 150hp or 165hp Franklin-powered airplanes will be able to use my 337 as approved data. The caveat will be that the low pitch stops of the prop will have to be set to accommodate the maximum RPM of the respective engines - something that can be done in the field by a qualified A&P.
The AOC and DER agreed there were no technical issues with approval and, barring any schedule or review issues, I should have my field approval within six weeks.
The engineer at MT is running some numbers to see which blade profile - classic or scimitar - would work best for this installation. In the interest of keeping an original appearance, my preference is for the classic blade profile, but if there is a significant performance benefit of using the scimitar blades, I will use them. MT will finish the prop in any color I want and I'm on the fence about black blades to match the appearance of the Aeromatic or white blades with red tips to match the airplane's paint scheme. I went with white blades / red tips / red decals with the Aeromatic on my red Fairchild and it looks AMAZING - so we'll see. The profile of the new spinner that comes with the prop will match the profile of the factory spinner.
If the prop is done before the 165hp engine, I'll install it on the existing 150hp engine so I can have an 'apples to apples' comparison regarding performance improvements. Regardless of which engine is on the airplane at the time, I'll share my performance results with the group, along with a copy of the approved 337 and any other pertinent data.
Best Wishes,
Brad Donner
NC86916
