Comfort level between engines

[SonexN76ET]

I was absolutely confident flying the Sonex factory aircraft in the Sonex transition training. I felt as confident in that factory built Sonex plane as I have in any aircraft.

In flying the Aerovee powered Sonex I built, I am not as confident, but that confidence grows with each flight. I think about each step of the engine build and worry about each thing that could go wrong. But in reality as long as the engine gets fuel, air, spark, cooling, and lubrication there is little that can go wrong. Check the oil and fuel before each flight, look for leaks and loose nuts and bolts, wires, and fittings each time you have the cowling off. Smell the oil each time you check the dipstick. Smell is a good indicator of the internal health of the engine. It should not have any burning smell or foul smell. Don't forget to torque your propeller bolts at each oil change or as recommended by the propeller manufacturer.

Build and install the engine according to the plans for the ultimate in confidence. I tried a blast tube going to the vicinity of the AeroInjector. I believe this blast tube may have caused excessive condensation on the AeroInjector that caused a partial freezing of the condensation on my air filter causing my engine to stumble for a second or two on a subfreezing day at altitude. It then seemed to "swallow" something and roar back to life. So, for me, no more blast tube. Mine is now strictly according to the plans and runs fine.

On a Rotax 912 there are in reality a lot more things that can go wrong with it. A 912 requires a fuel pump and requires electricity for the ignition system. It is water cooled and needs a properly installed cooling systems. The twin carburators need to be rebuilt every 350 hours. If you think tuning an AeroInjector is difficult, try rebuilding and tuning dual Rotax carbs.

On any aircraft you have to be prepared for an engine failure. The engine failing is not going to kill you, your actions after the engine fails will determine your fate. Above all else, do not stall the airplane after an engine failure! Of all the Sonex accidents, it is the stall/spin at low altitude that resulted in almost all the fatalities. Practice your response to an engine failure! Maintain the best glide speed and then make a normal landing. Don't try impossible turns back to the airport below 800 feet AGL. There have been several people who survived by simply gliding into the tree tops. An engine failure in a Sonex at worst should be no more than running your four wheeler into the nearby terrain at 37 mph.

So, bottom line is I am gaining more and more confidence in my Aerovee. For ultimate in reliability, build it and install it according to the plans. Beware of blast tubes and "fresh air" intakes you design and fabricate yourself and other modifications as they can have unintended consequences. I love the simplicity of the Aerovee.

I can hardly wait for my next flight!

Jake

[DCASonex]

Right or wrong I always feel more confident flying behind a Rotax 912. They just seem so much more quiet and smoother. I have flown plenty of jabiru engines and flown my own Aerovee for 60 hours now. I never have never really felt my Aerovee would stop on me during flight however. I have enough confidence to fly behind Aerovee I have bought a second one for my Sonex I'm building now. Saying that though if the factory would change their minds and support a rotax as an engine option I would have gone down that road without a doubt. I know people have done this before for an engine option but this time for my plane I wanted something built exactly as the plans state.

Would say much the same for my Camit engine. For all the technical improvements over my old Jabiru, the thing most everyone who hears it notes that it sounds so good, just smooth and powerful. That alone adds to confidence.

David A.

[daleandee]

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[SonexN76ET]

Some of you stated you prefer some other engines to the Aerovee because they were "smoother and quieter". Well, I bought some ThermoTec heat and sound and vibration dampner material from aircraft spruce and put some along the bottom of my firewall inside the cockpit and some on the floor by my feet and a few small squares inside the tail on the bigger panels. What a difference! Talk about smooth and quiet! On a recent flight I had reduced power after a climb to 3080 rpm and panicked for a moment because I thought I had lost power... Nope the engine sound and vibration were just so much lower. Makes the cockpit of my Aerovee powered Sonex all the more comfortable and pleasant. I am sure passengers will really appreciate it. I used less than three pounds of the rolled material. To me, it was worth it.

[Bryan Cotton]

Jake,
Would love to see some pictures when you get a chance. Thanks!

[39cubcoupe]

Had over 400hr on my Sonex Aerovee in only 20 months. I was very diligent on engine maintainence. But, always felt a degree of non comfort with Aerovee. NTSB reports confirm why you should have major concerns.

[SNX1508]

Had over 400hr on my Sonex Aerovee in only 20 months. I was very diligent on engine maintainence. But, always felt a degree of non comfort with Aerovee. NTSB reports confirm why you should have major concerns.

A quick search for "AeroVee" in the NTSB database from 1990 to present returns 7 accidents. 2 A/C ran out of fuel, 1 had a known issue with "an improperly calibrated carb", one had "improperly adjusted valve train". The other 3 crashed due to loss of power due to unknown reasons.

So, please be a little more specific in your reference to the NTSB reports and concerns for flying behind an AeroVee engine.

Thank you,

Terry

[nwawingman]

Some of you stated you prefer some other engines to the Aerovee because they were "smoother and quieter". Well, I bought some ThermoTec heat and sound and vibration dampner material from aircraft spruce and put some along the bottom of my firewall inside the cockpit and some on the floor by my feet and a few small squares inside the tail on the bigger panels. What a difference! Talk about smooth and quiet! On a recent flight I had reduced power after a climb to 3080 rpm and panicked for a moment because I thought I had lost power... Nope the engine sound and vibration were just so much lower. Makes the cockpit of my Aerovee powered Sonex all the more comfortable and pleasant. I am sure passengers will really appreciate it. I used less than three pounds of the rolled material. To me, it was worth it.

I looked for this on Aircraft Spuce website and it looks like you might have used Thermo-Guard FR by Thermo Tec. It that the material you ordered?

[SonexN76ET]

I bought mine from Amazon, but verified it was the same stuff Aircraft Spruce was selling. It is Thermo-Tec 14620 60" X 36" Heat and Sound Suppressor. The product states: "
In addition to the polyethylene film the foil surface provides direct protection from radiant heat
Great for areas like firewalls, floorboards or doors
The Suppressor is also 70 mil in thickness, contains a high temperature adhesive backing and is easy to trim and fit
The Suppressor will reduce various road noises, engine noises and improve driver comfort and concentration"

I put the material on the inside of my firewall and on the floor up to the mid point between the spar and the firewall.

I also put a 8x8 inch square on the floor under the luggage sling and an 8x8 inch square on the floor in the section behind the luggage sling.

I am also going to experiment with putting an X made up of the material cut out of 2 inch strips on the side panels in the two forward sections of the tail (baggage compartment and section behind baggage compartment. I hope that these X shape cut outs will stop the oil canning and resonance in the tail without adding undue weight.

I have noticed significant sound and vibration reduction. It is still very loud at wide open throttle, but any power settings below that are significantly more quiet.

I also put weather stripping around the canopy. This cuts down on drafts and wind noise and keeps the cockpit dry.

Thanks,

Jake

[nwawingman]

Thanks Jake! Just the information I was needing.