WOT Straigh & Level AV2180

[Captain Clanger]

Hi,


New to this board, but a Sonex lurker for many years ... now in a position to acquire one.

My question is .... (and I've read as much as I can find on the AV2180) ....

Is the aerovee up to delivering 100% power in straight and level?

If there is a concern, is it confined to CHTs or should I be mindful of other areas.

I note that in discussions on the Turbo option (if ever be produced?) 80% (of 100hp) is discussed - so I assume (if well qualified poster) that 80hp is no problem generally.

A secondary question would be what RPMs am I lightly to see WOT S&L with a stock prop.


Thanks in anticipation.

[MichaelFarley56]

Hello Captain,

I'm not quite sure how to answer this, but if the AeroVee is producing a full 80 h.p. at 3400 RPM at sea level, then yes the engine is plenty capable of producing that power. Most of us AeroVee owners won't run their engines that hard for prolonged cruise operations, but generally speaking the engine will do just fine. On my engine, it will happily run anywhere from 3000-3300 RPM for prolonged durations. Last fall, when I was chasing Mark Waldron down to Crossville, I don't think my RPM was below 3300 for over 2 hours!

Remember though, as we climb in altitude and the air density decreases, power output on the engine will also decrease, so even if you're turning a full 3400 RPM at high altitudes, you won't be producing the full 80 h.p.

As for your next question, I can tell you that, on my airplane, full throttle RPM in level flight will produce RPMs of close to 3450-3500 RPM. Slightly over redline but I'm okay running that RPM for a few minutes to test things. It's important to remember though that the airplane itself can have a major effect on the engine readings. If the Sonex is built straight, light, and has all fairings installed, it will go faster and as a result the engine will turn higher RPMs. On the other hand, you may have a perfectly healthy engine that can't turn full RPMs because the wheel and gear leg fairings aren't installed, the airplane is heavy, etc.

Does this help answer any of your questions?

[Brett]

I can't help but be curious here ;-) but what speeds were you seeing at 3300rpm and full throttle?

[radfordc]

Is the aerovee up to delivering 100% power in straight and level?
Yes, at least for a while.

If there is a concern, is it confined to CHTs or should I be mindful of other areas.
CHTs may be a concern. I've never held my engine at WOT in level flight for long enough to have excessive CHTs.


A secondary question would be what RPMs am I lightly to see WOT S&L with a stock prop.
3450-3500

[MichaelFarley56]

I can't help but be curious here ;-) but what speeds were you seeing at 3300rpm and full throttle?

I can't remember with absolute certainty on that Brett, but I believe 3300 rpm was giving me around 135 indicated mph and flat out (3450 rpm) was around 145 indicated mph. It's been a while since I ran the engine that hard though!

[vigilant104]

Last fall, when I was chasing Mark Waldron down to Crossville, I don't think my RPM was below 3300 for over 2 hours!

For the record and in my defense, the only reason I had the throttle opened that much was to prevent Mike's slippery Waiex from overtaking me and chewing up my little airplane. It's been awhile and I don't recall exactly, but I think my RPMs might have been a bit below Mike's 3300--maybe my 54x44 Sensenich is a bit coarser than Mike's Prince P-tip. I think 135 MPH IAS is about right, we were at approx 3500 MSL IIRC.
I was at my max allowable weight on that trip: my wife and I, a couple of small bags, tie downs, and all the gas the plane would hold. These are fun little airplanes and they will go. I've noticed that it's important to be in coordinated flight--getting lazy feet in cruise and letting the bean slip out from dead center seems to cost more speed than it does in a C-152, etc.
Mark