This is how the upper nose gear strut looked when I first made it with fiberglass laid up over modeling clay right on the plane:
I was happy with it but as I worked through the more obvious drag items I finally came around to taping the joints. Here is an early tape job on the fairing:
The tape is "Gaffers" tape I think it is used in the movie industry but I'm not really sure. What I am sure of is it can be worked to adhere to compound curved surfaces very nicely. That quality doesn't show well in this photo but it is almost a pleasure to work with and it has STRONG adhesive. I have flown several tests with it on all of the landing gear components. It covers and holds up very well in almost every instance (I had a couple of little streamers off of the right main gear on an earlier flight) this one (the cuff at the top of the NLG strut) has
NEVER stayed on in high speed flight.
I went to the auto parts store and bought some black RTV stuff in a tube labeled Gasket Maker type 273. I put wax paper around the strut and applied this material to the inside of the forward part of the "cuff"and mounted it with screws to the cowl. I let it cure overnight then removed it and found that it stayed firmly attached to the cuff but it separated fron the wax paper easily, leaving a nice conforming rubber seal. If I did it again I could do better but it obviously conformed to the shape of the strut fairing perfectly. So, I put wax paper around the trailing edge of the strut and did the rear half of the cuff and it worked well too. I tried to add the material to the rear edge of the forward part and the front of the back part thinking I could compress and or trim the build up to seal the gap between the two parts of the cuff. That didn't work at all and I had to cut it off in order to install the cuff fairing parts on the bottom of the cowl around the strut. Still I had the best seal around the strut I ever had and I felt it was time to apply the Gaffer's tape once again and see if there was any effect.
Yesterday the clouds were too low to get to my 6,000 ft density altitude to conduct the test. The tanks were full, The Nav antenna elements were, removed, the NACA inlet vents had their coverplates installed all of the landing gear fairing seams were carefully taped, the subfairings were installed on the wheel fairings and taped. Everything was ready for today's perfect test day - the sky was clear and the surface winds were dead calm. The one thing I do for racing that I forgot was to remove the tiedown rings and cover the holes with the little discs I make from extremely thin adhesive backed Contact shelf paper. I remembered when I was pushing the plane back in the hanger.
I wanted to test a three things (1) would the tape stay on, (2) what speed could I achieve at 2720 RPM and (3) what speed could I achieve at 2630 RPM both at 6,000 ft d. alt. flying a triangular course. I flew the course at maximum RPM (2720) and it sounded prop noise ragged then I pulled back the prop to 2630 and immediately continued around the course again with a softer sounding prop (it seemed less labored and smoother).
(1) The Tape stayed on perfectly!
(2) 360 GPS Track speeds (kts) at 20 second intervals = 186,186,185,186,186;
120 GPS Track Speeds = 191, 190, 191, 191, 191;
240 GPS Track Speeds = 174, 174, 175, 175, 174
Yielding a wind of 9.8 kts from 256.7 degrees and a KTAS of 183.8 kts
(3) (same three) GPS tracks:
360 = 186, 186, 185, 185, 185
120 = 190, 190, 190, 189, 189
240 = 175, 175, 176, 175, 174
Yielding a wind of 8.7 kts from 255.7 degrees and a KTAS of 183.4 kts
I think that solves the tape blowing off problem. I wish I would have thought about the tie down rings before the flight but the conditions were the same for both flights so it had no bearing on the difference between the two RPM speed results.
Bob Axsom
CJ
