Speedy11(at)aol.com Guest
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Posted: Thu Mar 10, 2011 9:14 pm Post subject: Speed Mods |
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The speed mods are adding very little weight. The largest wight increase was due to the tail weight (about 2 pounds) but I have removed it since there was no perceived improvement. The other changes are fiberglass or carbon fiber fairing shells and are light weight. However, I have flown my airplane with and without a 200 pound guy in the back seat and the extra weight makes no difference on top speed. I got 193 KIAS at 1000' MSL no matter the weight. Weight does make a difference for climb ability. If you are operating off a short, turf runway, then lower weight would be the best option.
Regarding the comments about using P Mags on an IO-390, I concur with all comments.
I never ran my engine on regular mags, so I can't give a direct comparison, but I am very pleased with P Mag performance and with product support. It doesn't get any better than Brad Dement's P Mag support. I had a few issues early on and Brad promptly solved each one. I have another little problem I need to contact him about - the RPM on my engine monitor is inop when the engine is cold - RPM signal is from the P Mags. As soon as the mags warm up, it works normally. The problem only surfaced recently and I have not discussed it with him.
Timing of the P Mags is dirt simple.
I'm running NGK BR8EIX Iridium auto plugs with the P Mags set to 39 degrees BTDC. These plugs are a bit hotter than the BR8ES I was running before. I taxi with the engine leaned and I have zero plug fouling. I am considering making a harness to fit aircraft plugs and try flying with them because I am losing a tiny bit of compression with the auto plugs. With the E Mag Air plug adapters, the auto plugs do not reach as far into the combustion chamber as aviation plugs, so a bit of compression is lost. I usually run the engine at peak although running 50 LOP works well.
5500' MSL 2200 RPM 21.6" MP 150 KIAS 174 KTAS FF 9.2
5500" MSL 2290 RPM 22.5" MP 164 KIAS 188 KTAS FF 9.8
1000' MSL 2200 RPM 18" MP 120 KIAS FF 6.7
I can't quite get the low FFs that other guys are getting. Can't pinpoint a causal factor, but doubt it has anything to do with the ignition.
Stan Sutterfield
In a message dated 3/10/2011 3:06:07 A.M. Eastern Standard Time, rv8-list(at)matronics.com writes:
Quote: | Very interesting. I'm curious how much weight all that stuff is adding.
Have you weight it with all those speed addons? (Hoping for lower weight
over higher speed for mine)
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