Hello all,
As I'm working my way toward engine installation on my TF 1/5 p-51, I'm wondering if it is absolutely nessesary to build in "down right thrust" at the fire wall. The bird will have a DA-50R with Joe Eagle's reduction drive and a 4 blade 26" prop. I was hoping some of you veteran warbird pilots could chime in on this.
Thanks for your help,
Carver

alot of people don't like it built in to the firewall because it is too hard to change it around.if in dout build it staight and use shims or standoffs that have the 2 or 3 degrees right and 0 down.for a warbird i would leave out the down thrust

Just because you are using a prop drive does not mean you do not need down or right thrust. You are exchanging high RPM,small diam. prop disc for low RPM, large prop disc with lots of pitch. This means more torque, and gyroscopic forces operating on your nose. I would go with the right thrust and down thrust that is recommended. you may have to add more right thrust due to greater "P" factor due to the larger diameter prop. just watching your six Bro. By the way, have you asked Joe what he thinks?
Gary

No, I have'nt mentioned it to Joe yet, but thats probably a good idea. What do you think would be the result if there were no down or right thrust while attempting to fly this air plane. Would it be impossible? Thanks for your imput guys.
Carver

gary9648 is right.

The large 4 blade would create more torque. Not only due to its size and pitch but just turning a larger mass.

Steve

Well first, no right thrust: Plane will vere left very hard on take off or any vertical line. No dwn thrust will cause pitch changes due to power settings and could lead to a lot of dwn trim at power, and when power is removed like on final approach, the plane will dive into the ground with not enough up elevator to pull it out. CRASH! Do not do it Bro. Just watching your six.
Gary

Thanks Gary,
Thats what I needed to know. Just curios, how is this overcome on the full scale aircraft? Thanks for watching my six!

They use right and down thrust in real aircraft.
Darryl Usher

Exactly, thanks Daryl. The Mustang has a few degrees off set in the vertical sab that works as right thrust. This help compensate for all the torque the Merlin puts out.

Seem like the engine had all the right thrust you could get in the fuselage.
Darryl Usher