Are the sonex performance numbers correct?

[kevinh]

Hi ya'll,

I think I'm just about to order a full waiex kit from sonex (hopefully finishing the build in a couple of years and then putting in a turbo-aerovee). A question on performance: Are the numbers listed on the sonex website (TAS speed at 8K, rate of climb, etc...) fairly 'honest'? I know the Van's numbers were pretty accurate (but work/tuning was required to reach the published numbers). However, I don't know much about the sonex ecosystem.

Are ya'll getting numbers approximately like you would expect for your engine install?

Kevin

[wlarson861]

I think the 150 to 170 cruise speed is pretty close for a Jab3300 Sonex or Waiex(Kip weigh in here). It is a bit optimistic for the non turbo AeroVee. I fly with the lower compression auto fuel version on car gas which yields less power than the 100LL compression setup. Today I was at 4500 and my true airspeed was around 130 MPH. That's not bad for 4 gallons per hour. Also those numbers are based on a well broken in engine and an "in rig", light weight air frame. Every plane will be a bit different in that most of us can't resist adding all the toys we never had as kids which piles on the pounds by the time we get to the airworthiness inspection. I had to have a swing back canopy and leather interior which both added weight. Fatter the empty weight the less the performance etc. I am about to upgrade to the turbo so that will change everything. I'm not sure what numbers you looked at but for me the performance is as expected. The Sonex line is for me the best trade off between performance and money. I would love to have a Lanceair turbine pressurized plane but I couldn't afford to taxi it to the fuel pump, let alone the insurance, so I'll stay with my little polished plane and enjoy the flight. If the Sonex line fits your mission it is a great plane to build and a blast to fly. Good luck on your build

[N111YX]

As I tend to conservatively operate airplanes that I pay for, I only use low-end cruise power settings yielding about 145-148 mph true at 2650-2700 rpm. Phase I testing revealed top speeds in the 160's but never 170, regardless of altitude. To run in 160+ in my airplane requires near full throttle settings and I don't care for the extra noise and fuel flow. I've used two props and both the standard Sensenich and Prince produced similar cruise numbers but the Prince has an edge in climb.

I have a second generation hydraulic lifter engine and it's been said by some that the solid lifter produces more horsepower. Combine that with a cruise-biased prop and 170 mph may be more easily attained...

[fastj22]

I can see 170 MPH TAS at 8000ft at 2900 rpm with my P-tip. Fuel burn is around 7-8 GPH. I typically cruise at 2700RPM which yields around 150MPH TAS and burns 5-6 GPH.

[kevinh]

Thanks for the great replies. So the numbers do sound fairly close... (Though any other replies would be welcome/useful for future searchers)

[DCASonex]

160+ MPH TAS cruise at 2,850 RPM and 5.8 GPH at 7,500 -8,500 in my Sonex with 3300 (true with both the original Jabiru and now CAMit engines) and standard Sonex prop, is fairly typical and I have one of the heavier Sonex with lots of comfort goodies.

Of course that is True Air Speed, not ground speed. There is always a head wind. :-)

David A.

[LarryEWaiex121]

Larry here with Waiex 121YX and my numbers and Kip's seem almost identical. I confess to flying 99% of the time without gear leg fairings because I feel they are a pain. Just me.
I figure level cruise at 6,500' at 2750 will show 148mph in no wind.
I have gone full throttle in level flight at 8,000 ft for the better part of 3 minutes and watched the airspeed wander between 178-183 in level flight. Now I was running right at 3300rpm and fuel flow was showing a nice comfy 12.4 gph.
I guess if you wanted a quick sprint to your destination of barely over and hour and didn't mind your fuel bill being over twice the normal rate it would do the numbers.
After 400 plus hours I have pretty much determined its a safe bet to flightplan 118 kts for an average 1-2 hr flight and your going to be spot on.

Larry
Waiex 121YX

[tonyr]

I have 3300 envy.. :mrgreen:

[fastj22]

Here is shot of my EFIS enroute to OSH last year. We were near gross and running at 2700RPM.

[radfordc]

When Bob and I flew together our performance was almost identical for our two Aerovee engined planes. At cruise power burning less than 5 gal/hr; indicating 117- 120 mph, and TAS 123-125....at around 3000 MSL.