trying to mount a saito 180 on the Hangar 9 73 cap 232 and can't find out how far to put the prop hub from the firewall. []

I have a PDF copy of the manual if you would like me to email it to you.

But, actually, given the Hanger 9 slotted motor mount and the optional placement for mounting the cowl this should not be that difficult.

Here are excerpts from the manual:

MOUNTING THE ENGINE

Step 1. Mix up approximately 2 oz. of 30-minute epoxy and brush it on the firewall to seal it. Allow the epoxy to dry.

Step 2. Locate the two metal motor mounts and associated mounting hardware. Note there are slots on the firewall, so the width of the engine can vary.

Step 3. Mount the metal motor mounts on the firewall using the hardware provided. Do not overtighten the bolts as the width of the mount will vary with the size and type of engine mounted. Note: It may be necessary to cut off the bottom motor mount bolts flush with the nuts to insure that they do not puncture the tank.

Step 4. Trial fit your engine on the motor mount. Once the proper width has been determined, tighten down the motor mount bolts. You can then remove your engine while completing the following sections. Prior to installing the control linkages, you will want to remount your engine.

ATTACHING THE COWL

Step 1. Using a Moto-Tool, grind out the prop and cooling openings in the front of cowl. Cut out the large “U” shape in the bottom of the cowl so it will slide over the fuselage and landing gear.

Step 2. Trial fit the cowl to your engine. Note those areas that will have to be trimmed out, such as needle valve openings, external fill openings, etc.

Step 3. Mark the locations with a felt tipped pen. For illustration purposes we are showing the openings for the Saito 1.50 mounted in the CAP 232.

Step 4. Carefully cut out using a Moto-Tool.

Note: If you’re using another type of engine, it will be necessary to carefully cut portions of the cowl that are located differently from where we show with the installation of the Saito 1.50.

Step 5. Slide the cowling onto the fuselage.

Note: It may be necessary to trial fit the cowl with and without the engine muffler attached.

Step 6. Tape the cowl securely in position and check that it fits correctly. There should be ample clearance (1/8¢¢ around the engine and muffler). Also check that the prop hub is centered in the opening of the cowl and that the prop hub extends at least 3/16" forward of the cowl. Locate the cowl hold-down screws so there are two on either side of the cowl. Do not locate in a trim area because the trim can be damaged as the screw is tightened down. The blind nut location should be in the fuselage area, near the bulkhead. Mark the four mounting holes with a felt tipped pen.

Note: Be sure its cowl is pulled down tightly and held securely prior to drilling a hole. a 1/16¢¢ drill bit is used to drill the holes.

Step 7. Once the mounting holes have been marked, and you’re satisfied with the location, drill two holes on each side of the cowl using a 1/16¢¢ drill bit. Use masking tape to temporarily hold the cowl in position. It is important the cowl be held down tightly so there is a tight fit when the cowl is attached.

Step 8. Remove the cowling and enlarge the four holes in the cowling just enough to fit the rubber grommets in place.

Note: On some engines where the carburetor is not easily accessible, a removable fueling valve can be used. Dubro’s DUB334 is an excellent choice and should be available at your local hobby shop.

Step 9. With the cowling not on the fuselage, insert the 4-40 button head bolts through the holes you drilled. From inside the fuselage, place a 4-40 blind nut on the bolt and pull on the button head bolt to “set” the blind nut into the fuselage.

Note: You may wish to put a small drop of thick CA on the flange of the blind nuts to help prevent them from coming off the fuselage when installing the button head bolt when attaching the cowling.

Step 10. Align the cowling on the fuselage and secure it with the button head bolts. Do not over-tighten the bolts by smashing into the rubber grommets as this will take away the vibration isolation of the grommets.

Note: Four pieces of self-adhesive trim tape are included for trimming the cowl.

i know engine is in next county and was trying to finish the decals up trim tape on cowl and was looking for how far out to put it so the trim will line up

What I was trying to point out is that you have some engine placement on the motor mount. Given this info, the Saito 180's measurement from the rear mounting hole to the prop hub is 3.7". The distance from the front mounting hole to prop hub is 2.76".

After bolting on the engine mount (don't have to worry about width at this point) and dry mounting the cowl with tape, measure the distance from the front end of the slot in the engine mount and the opening of the cowl. This measurement must be less than 2.635 inches. Then measure the distance between the aft end of the slot in the engine mount and the opening of the cowl. This measurement must be greater than 3.85 inches. If both of these measurements agree with mine then permanently mount the cowl and attach and line up your decals. If they don't adjust the dry mount of the cowl until they do. When you mount your engine all you will have to do is slide it to the right position to enable a 1/8" clearance between your prop hub and the cowl.

This is the best way for me to describe it to you because I don't not know the measurement of the engine mount but do know the measurement of the engine, which you can find here:

http://www.horizonhobby.com/ProdInfo...ingles2004.pdf