I have a question about engine mount isolators for my RV-8. I'm about to mount a Superior O-360-A1A to the 8 and am debating whether or not to pay the extra money for the Lord aerobatic mounts.
Apparently the Lord J-9613-12 is used for straight and level flying ($165 ea) and the Lord J-7764-31 is designed for aerobatics ($250 ea).
Lord says that the J-9613-12 has a "compression" sandwich and a "tension" sandwich on each side of the engine mount - the compression side takes the 1G weight of the overhanging engine. That's why the sandwiches are reversed top to bottom. They don't recommend flying negative g's with this arrangement since the engine motion will be higher upside down. The J-9613-12 mount is a softer system than the J-7764-31 which has compression sandwiches all around. The result is a better vibration isolation.
The higher cost of the aerobatic parts are because they're made from a natural rubber that uses a special cure system that's 3+ times longer than standard. The press time makes them more expensive but I apparently they'll out-last anything out there by far.
Most of the above is from Smokey Ray's 2015 VAF post but wanted to see if anyone else has opinions that are contrary to the above?
Thanks!
__________________
Mark - KGAI under DC SFRA where big brother's always watching.
Building RV-8 for aerobatics, N184MR aka "Drone Killer"
Flying RV-8 N83SE to get my fix.
Own 2011 Piper Meridian for the trips.
Apparently the Lord J-9613-12 is used for straight and level flying ($165 ea) and the Lord J-7764-31 is designed for aerobatics ($250 ea).
Lord says that the J-9613-12 has a "compression" sandwich and a "tension" sandwich on each side of the engine mount - the compression side takes the 1G weight of the overhanging engine. That's why the sandwiches are reversed top to bottom. They don't recommend flying negative g's with this arrangement since the engine motion will be higher upside down. The J-9613-12 mount is a softer system than the J-7764-31 which has compression sandwiches all around. The result is a better vibration isolation.
The higher cost of the aerobatic parts are because they're made from a natural rubber that uses a special cure system that's 3+ times longer than standard. The press time makes them more expensive but I apparently they'll out-last anything out there by far.
Most of the above is from Smokey Ray's 2015 VAF post but wanted to see if anyone else has opinions that are contrary to the above?
Thanks!
__________________
Mark - KGAI under DC SFRA where big brother's always watching.
Building RV-8 for aerobatics, N184MR aka "Drone Killer"
Flying RV-8 N83SE to get my fix.
Own 2011 Piper Meridian for the trips.
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