Canuck1

I am about to secure the two vertical fins to the tail of my Lancaster. I have been building as per the plans and I have a question regarding the twin fins. The starboard fin seems to have about 3 degrees toe in and the port fin has about 1 degree. Is there any requirement to have toe in on the vertical stabs? It seems that toe in will add to stability, however being that this is my first twin tailed aircraft I am not sure.

Thanks.

Craig.

Uncle Heinkel

Hi Craig,
Not sure about any rules of thumb for fin offset, but FYI, I have a Stafford B-24 with four O.S. 26's.... the fins are set up with no offset and it flys just fine. No unusual trim settings.....

H.

Canuck1

Thanks for the reply. This is my first multi engine aircraft. I may need some help with the flying characteristics regarding this model. I want to make sure I have all the info regarding the fins before I secure them. Keeping them straight seems the logical way to go. It would reduce any in flight forces on the tail in flight. Once again thanks for the information.
Feel free to email me, as I want to learn more regarding multi engine flight. [email protected]

Craig.

Uncle Heinkel

I was thinking about why the toe-in offset was specified.....I'm guessing to keep it tracking straight and true and a little extra for torque?

Trying to keep the fins at 90 degrees in every axis while the epoxy set was a real chore with my B-24. I used tape and a bit of CA to tack glue them in the correct position while the epoxy set.

Should be easier if you have a tight fit that is correctly aligned already....I didn't.

Love the Lancaster......how about some pictures?

H.

Canuck1

The plans do not specify any toe in. It seems from looking at it there is some. I trimmed the edges as per the plan sheet. As it stands now, it is a good fit however there looks like some toe in. It could be my eyes. LOL It is obvious to me. I am very particular when it comes to construction. It would be easy to rectify, just a bit of work. It is a 1/16th balsa sheeted horizontal stab. Just need to trim off the sheet and sand the foam slightly. I would post some pics, however, my pics are to big for them to take. Send me an email I will send some pics. It is slowly beginning to take shape. With the fuse glassed and sanded it looks pretty good. The fuse is a wood box with a foam outer to achieve the shape. It took a while to get it right prior to glassing. The remainder should be much easier as it is all balsa sheeting to glass.

Craig.

springer-RCU

The toe-in, on a twin-engined design, will have the effect of automatically opposing the asymmetric yaw that results from the loss of an engine.

Springer

Canuck1

Then is toe in a good thing? I am concerned with the constant pressure on the fins in flight. It will not be traveling at a very quick speed, I am just concerned that failure may occur. The plans do not state toe in. I think if they were at 90 degrees it would be better for overall performance. The two fins would not be working against each other?????????/

Craig.

William Robison

My Feedback: (3)

Canuck:

Just set them at zero offset and be done with it. I have never heard of any such thing as "Toe-in" on the vertical fins.

Bill.