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Thanks Todd, Now have an intercooler if I can fit it in, so getting there. Interesting times with the “muffler” which turns out to be an AES resonator and not a muffler at all but similar. This is the muffler that Chris McDonald used and modified to make fit under the cowl. Will attach the photo again as will be an interesting discussion with the manufacturer. These blokes claim to be rotary experts as well. They also sell actuators, similar Price to Ebay. Neil Unger From: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Monday, July 20, 2020 2:10 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: wastegate actuator Hi Neil; My old stock diaphragm actuator gave me ~6psi. However when it failed on take off, due to a burst diaphragm, the boost instantly jumped to about 16psi, which was surely an exciting event with very impressive performance. I quickly throttled back before any detonation could occur. This is adjustable by changing the springs. And it is a piston so it won't suffer instant failure due to a burst diaphragm. It's failure mode would be due to a worn o-ring on the piston, which would show as slowly degraded control ability and would be a cheap and easy repair. And it will save you 0.3 lbs It ships from Taiwan, so it's on the right side of the pond for you. You certainly can use the stock one, but due to it's sealed design, it can't be taken apart to inspect the diaphragm and since it's located right next to an extremely hot heat source it's life time is limited. In my job as an instrument mechanic in a steam plant, I have to repair many automatic valves. We always try to avoid using diaphragm valve actuators in high heat areas, instead opting to use piston actuators. The heat can affect the o-ring on these as well, but the failure doesn't result in complete loss of control for the operator, and even if a proper rebuild kit is not readily available, a generic o-ring can be used or even make one using a splice kit and it will still give years of reliable service in some circumstances. The only advantage to a diaphragm is response speed as it will be slightly more responsive, which could be advantageous in a street racing application, but for our use in aircraft this is of no concern. So, yeah you can use that one, but I recommend the investment in a piston type actuator. Group, Can anyone tell me what PSI the standard RX7 waste gate actuator gave? Only need 5 -6 psi and once again why chuck out a unit if it will do the job?? Update on noise, seems just a turbo will not quieten the beast enough for my liking (an old age thing ?) Have to add another 7 Kg muffler which will need repacking as it blasts out the packing. Going with AES which is what Chris Mc Donald used on its own to good effect. By the way FYI Chris is in Intensive care up north QLD having contacted some disease which has paralysed him totally. Apparently recoverable in 12 months --- that is a long time in intensive care. He can now open his eyes, smile slightly and keep his tongue in his mouth unaided!!! Met him in Caloundra just a few weeks before he ended up in hospital last Feb. I do not have to point out the grief this is causing his family. So the wastegate actuator --- any info? Neil.
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