Some Notes on the Lanier F-86D ARF
02-12-2005, 10:00 AM
#1
Some Notes on the Lanier F-86D ARF
Just now finished it, and am awaiting good weather to break in the engine and fly it. It's modeled after the Sabre 6 that Burgess Meredith flew in that old B movie, "The Last Chase", starring Lee Majors. I completely recovered the wing a stab, and sanded the fuse and fin so they could be repainted. I used yellow econokote and black baron black covering, along with lustrekote white primer, gloss black, and clear coat. All the graphics are clearcoted, as is the entire fuselage, fin and cowl. Hopefully it will all stay on.
Lanier's fiberglass and balsa work is very nicely done, very true, and very light. The supplied fuel tank and plumbing are especially nice. First time I ever put a tank together and didn't have to bend tubing - it was all done for me.
I could not make the "y" pushrod affair for the split elevator work, and ended up using two Dubro Lazer rods instead. The nose wheel steering and throttle pushrods could not be made to work as designed, either, and required some fiddling.
The instructions for mounting the engine are vague, and as a result my engine is probably about 1/8 of an inch higher than it should be on the firewall. Also, the plastic engine mount provided is distorted, and I had to shim the engine to the right to get the spinner to center on the cowl.
The instructions say the CG is to be located at 7.5-8" aft of the LE measured at the fuse side. I could only do this by using a 2200 mAH battery located all the way aft, and about a half pound of lead, and it was obvious this was not right. The airplane weighed 7.5 pounds (specs say it should weigh 5.5) and would sit back on its tail with just a slight lift of the nose.
I went to this web site and used the diagram to calculate a CG location that is 25% of MAC:
http://www.nsrca.org/technical/tip_tricks/mac_cg.htm
The suggested CG came out at 6" aft of the LE as measured at the fuse sides. This happens to correspond with what is said on both the Tower Hobbies and the Lanier websites.
The aircraft does build nose heavy. To get the CG at 6" with a Tower 46 BB & a pitts muffler, I had to mount a 700 mAH battery to the underside of the stab (inside the fuse) and add 1 oz of stick on weights aft of the jet "exhaust". This brought the weight back to 5.5 #, and the wing loading to a manageable 23 oz per square foot.
I have no doubt this aircraft would have been destroyed on its first flight had I not corrected this. I really wonder why outfits like Lanier and Tower can't pay closer attention to the important details, as they do such a good job at design and customer support otherwise. It would have been very easy to put a notice in the box concerning the CG.
Bob Hunt
Cadillac, Michigan
Lanier's fiberglass and balsa work is very nicely done, very true, and very light. The supplied fuel tank and plumbing are especially nice. First time I ever put a tank together and didn't have to bend tubing - it was all done for me.
I could not make the "y" pushrod affair for the split elevator work, and ended up using two Dubro Lazer rods instead. The nose wheel steering and throttle pushrods could not be made to work as designed, either, and required some fiddling.
The instructions for mounting the engine are vague, and as a result my engine is probably about 1/8 of an inch higher than it should be on the firewall. Also, the plastic engine mount provided is distorted, and I had to shim the engine to the right to get the spinner to center on the cowl.
The instructions say the CG is to be located at 7.5-8" aft of the LE measured at the fuse side. I could only do this by using a 2200 mAH battery located all the way aft, and about a half pound of lead, and it was obvious this was not right. The airplane weighed 7.5 pounds (specs say it should weigh 5.5) and would sit back on its tail with just a slight lift of the nose.
I went to this web site and used the diagram to calculate a CG location that is 25% of MAC:
http://www.nsrca.org/technical/tip_tricks/mac_cg.htm
The suggested CG came out at 6" aft of the LE as measured at the fuse sides. This happens to correspond with what is said on both the Tower Hobbies and the Lanier websites.
The aircraft does build nose heavy. To get the CG at 6" with a Tower 46 BB & a pitts muffler, I had to mount a 700 mAH battery to the underside of the stab (inside the fuse) and add 1 oz of stick on weights aft of the jet "exhaust". This brought the weight back to 5.5 #, and the wing loading to a manageable 23 oz per square foot.
I have no doubt this aircraft would have been destroyed on its first flight had I not corrected this. I really wonder why outfits like Lanier and Tower can't pay closer attention to the important details, as they do such a good job at design and customer support otherwise. It would have been very easy to put a notice in the box concerning the CG.
Bob Hunt
Cadillac, Michigan
02-13-2005, 05:58 PM
#2
RE: Some Notes on the Lanier F-86D ARF
Update:
I made a mistake using the CG diagram. Went back to it tonite and redrew the whole thing. Turns out a CG that is 25% of MAC is exactly 8" aft of the LE as measured at the fuse. No way am I going to add enough weight to this plane to get that. I'll stick the 2200 mAH Rx battery back in, and then do another ground run up of the engine. If the nose won't get light at full throttle and full up elevator, I think I'll try adding a bit of up thrust to the engine.
Anyone have any ideas that might help, or have I built another expensive ceiling decoration?
I made a mistake using the CG diagram. Went back to it tonite and redrew the whole thing. Turns out a CG that is 25% of MAC is exactly 8" aft of the LE as measured at the fuse. No way am I going to add enough weight to this plane to get that. I'll stick the 2200 mAH Rx battery back in, and then do another ground run up of the engine. If the nose won't get light at full throttle and full up elevator, I think I'll try adding a bit of up thrust to the engine.
Anyone have any ideas that might help, or have I built another expensive ceiling decoration?
