World Models Corsair Question

[Rich_N]

Hi all,

I have just bought a second hand World Models Corsair which is in excellent condition except for a less than perfect repair to the firewall. I got it very cheap so don't mind having to make the repair.

The firewall is cracked about 1/4 way down and has been glued and repaired but not very well and I am concerned that the thrustline may be wrong.

Does anyone have any close-up photos of this area on their F4U, or can anyone help with dimensions etc. that will help me make sure I get this right when I rebuild it?

Thanks in advance!

Regards
Rich

The page for the model is at http://www.theworldmodels.com/para/products/airplanedetails.php?airplaneid=25#

[Corsair Driver]

The thrustline is not all that important. The alignment of the engine is. I could not download the picture on the website, but normally one wants and engine at 0 degrees or perhaps 2 degrees down with the assembled aircraft level to a work surface. Then it's important to be sure there is NO left thrust. A couple of degrees of right thrust is ok.
Do some measuring of the existing motor mount and original holes to see how the unit was assembled. Make your judgements from that information. What kind of material is the firewall made of? I presume it is plywood. Has the repair been laminated to the original? If only a split is readily seen, how about where it is secured to the fuselage? Are seams broken? Can you remove enought of the old firewall to duplicate it and replace it in the original location?

[Rich_N]

Thank you, Corsair Driver, you have confirmed what I thought - some right and possibly some down thrust. The problem I had was the large misaligned crack across the top of the firewall which seems to have created a slight '>' shape to the firewall thus shifting the motor alignment up and to the right.

I will remove the firewall, patch the fibreglass around the front of the fuse then install a new firewall - probably to align the engine with about 2 degrees right and a similar amount of down thrust.

I have posted some photos at http://www.flying-models.org/corsair/firewall_damage.htm if anyone wants to see how badly some people repair planes!

Thanks again.

Regards
Richard

[Corsair Driver]

Glad to be of some assistance. The pictures were helpful in understanding what you are faced with. Looks like someone had a hard landing on the front end. I had no idea what the construction looked like. My Corsair is built with zero incidence, but down and right is always a good idea. Be sure to use rudder to compensate for torque to the left when you are taking off. Also do not just "pull up" without allowing for proper airspeed to build up. The tail will raise quickly, but the rest of the airframe takes a while. Good luck with your repair and Corsair, Larry