An old report repeat on antennas and current status
When Jeanine and I built our RV-6A 1996-2004 our intention was to race in whatever cross country air races that came up. Usually one per year until SARL was created, now we have over 20 per year (www.sportairrace.org). With that focus during the original build, I contacted the manufacturer of the best looking "in the wingtip" antennas. When I told him that I fly IFR he told me that the antennas were intended for sport flying applications and he would not recommend them for serious IFR flying. That was a NO GO decision driver for me.
I could make cover plates for all of the external antennas, two communication, transponder and marker beacon (I already take off the navigation elements by unscrewing them), remove them for racing on site and reinstall them before flying home. The 12" stock wing tips have been replaced by a 3" streamlined tips of my own design and the performance of the com antennas placed in them for turn and finish line calls would be further compromised. I would have to route a coax to at least one wing tip and change the RF I/O connection to the race only coax someway (change connections, coax switch, etc.) disable the transponder (you don't want transmission attempts into an unloaded output, maybe some FAA problems there as well - depending on race location perhaps). Still, if I run out of more promising and less compromising opportunities the passive drag of external antennas will be kept in mind - I look at them and wonder each time I wash the belly.
The speed differential between out RV-6A and the current RV Blue race leaders is from 3 to 9 kts and I think I am going to have to deal with the thrust member of the speed equation to overcome that. Two of them will be in the AirVenture Cup Race next Sunday and we will see what we have accomplished so far. I am hoping this engine cooling air outlet mod cuts into the margin.
I completed a trial "final installation" of the new one piece cover this morning at 05:40 and there are some problems.
The 0.040" 6061 0 material I had available and used, is very soft. It is just a little harder to form than sheet lead so it shapes nicely but its softness causes mounting problems. I knew this from the 0.032" 2024-0 material used in the development cover. I planned to drill large mounting holes and use #8 hardware with dimpled washers to provide more distribution of the fastener head compression but I went too small at 1/4" dia and the washers are not all flat because of imperfect hole alignment. I plan on removing it today, increasing the hole size to 3/8" like I do on fiberglass and plastic parts installed with dimple washers and see if that works. If that is not satisfactory I will go to harder material for a new cover and cure the problem that way. Since I plan to leave for Mitchell, South Dakota for the race Friday morning there is some schedule pressure so I guess I had better eat, get cleaned up and head back to the hangar.
Bob Axsom
When Jeanine and I built our RV-6A 1996-2004 our intention was to race in whatever cross country air races that came up. Usually one per year until SARL was created, now we have over 20 per year (www.sportairrace.org). With that focus during the original build, I contacted the manufacturer of the best looking "in the wingtip" antennas. When I told him that I fly IFR he told me that the antennas were intended for sport flying applications and he would not recommend them for serious IFR flying. That was a NO GO decision driver for me.
I could make cover plates for all of the external antennas, two communication, transponder and marker beacon (I already take off the navigation elements by unscrewing them), remove them for racing on site and reinstall them before flying home. The 12" stock wing tips have been replaced by a 3" streamlined tips of my own design and the performance of the com antennas placed in them for turn and finish line calls would be further compromised. I would have to route a coax to at least one wing tip and change the RF I/O connection to the race only coax someway (change connections, coax switch, etc.) disable the transponder (you don't want transmission attempts into an unloaded output, maybe some FAA problems there as well - depending on race location perhaps). Still, if I run out of more promising and less compromising opportunities the passive drag of external antennas will be kept in mind - I look at them and wonder each time I wash the belly.
The speed differential between out RV-6A and the current RV Blue race leaders is from 3 to 9 kts and I think I am going to have to deal with the thrust member of the speed equation to overcome that. Two of them will be in the AirVenture Cup Race next Sunday and we will see what we have accomplished so far. I am hoping this engine cooling air outlet mod cuts into the margin.
I completed a trial "final installation" of the new one piece cover this morning at 05:40 and there are some problems.
The 0.040" 6061 0 material I had available and used, is very soft. It is just a little harder to form than sheet lead so it shapes nicely but its softness causes mounting problems. I knew this from the 0.032" 2024-0 material used in the development cover. I planned to drill large mounting holes and use #8 hardware with dimpled washers to provide more distribution of the fastener head compression but I went too small at 1/4" dia and the washers are not all flat because of imperfect hole alignment. I plan on removing it today, increasing the hole size to 3/8" like I do on fiberglass and plastic parts installed with dimple washers and see if that works. If that is not satisfactory I will go to harder material for a new cover and cure the problem that way. Since I plan to leave for Mitchell, South Dakota for the race Friday morning there is some schedule pressure so I guess I had better eat, get cleaned up and head back to the hangar.
Bob Axsom
Last edited: