post war tail AOI

[jgerard]

I was wondering if the post war BC12D horizontal tail AOI is not parallel to the Thrust line as described in the Model 12 service manual. I have a positive AOI on the tail compared to the thrust line string that I have located on the fuse using a set of prewar drawings (# 0893 I think)

[Robert Lees]

Re: post war tail AOI

Does it matter? It's non-adjustable.

[jgerard]

Re: post war tail AOI

Just was curious because my fuse does not match the drawings I have. I would have to find a set of drawings specific to the post-war fuse (if it truly is different) to reference during repairs. Or I am reading the drawings incorrectly?

Jason
N43643

[Ragwing nut]

Re: post war tail AOI

It is not on my '42 Deluxe. I just finished rigging it about 2 moths ago.

Mike

[VictorBravo]

Re: post war tail AOI

Sounds like an old fuselage repair might have tweaked it a little?

[Ragwing nut]

Re: post war tail AOI

Sounds like an old fuselage repair might have tweaked it a little?

If you are speaking to me, no. Only damage is a ground loop back during the war. Thrust line is parallel to the engine crankshaft. It also coincides with the firewall being vertical if you have good mounts. If you put the tail on a 55 gallon drum, it is VERY close to having the thrust line level and can be tweaked with air pressure in the tire. Horizontal has more incidence in it and requires another 18" or so higher in in the air to make it level.

I have seen a fuselage where someone shortened the upper longerons to make the horizontal parallel with the thrust line and it looked like it had a broke back. Had a funky Ferris serial number on it too.

Mike

[Forrest Barber]

Re: post war tail AOI

All B fuselages have same angle of incidence, same stab mounting points

[jgerard]

Re: post war tail AOI

So if my thrust line string stretched through my fuse is correctly positioned and level, and my stab attach points are supposed to be parallel to the thrust line ( mine isn't) I must have the wrong info on where the thrust line is measured on the fuse. I will use the stab attach points to level my plane in the jig for repairs and not the thrust line. I will also check my tail-post for the 3 deg FWD slant with my stab attach level and compare the Firewall area to be absolutely perpendicular to the stab attach points.

[jCandlish]

Re: post war tail AOI

Jason

While your measuring things up, could you tell me LOA, firewall to rudder-hinges?

Need to know for shipping.

Thanks
jCandlish
.

[Forrest Barber]

Re: post war tail AOI

Jason that sounds correct, I will pull a drawing and see . Whenever we do work on them , the leveling means is the stab attach points for & aft. Where the firewall & rudder post is I do not know... probably the 3 degrees 49 minutes that jumps out from memory ; but that is a calculated figure when we were doing the clip wing.... somebody with a bare fuselage jump in there with a measurment of tail post & firewall in the level condition. Saves me runing around in the rain.... I do feel for those folks up there in far NW...

[jgerard]

Re: post war tail AOI

Used one of those fancy "smart levels" and it told me that my firewall is absolutely perpendicular to my stab and that my tail post is +3 degrees canted foreword. BUT the thrust line I have stretched down the fuse is showing the stab to be about +1 deg positive AOI. Enough measuring, time to cut and replace tubing. I was shown a neat way to cut the longerons out of the clusters with a hole-saw using a pilot that just barely fits inside the longeron. I will make my version of the tool up and post some pics.