SonexBuilders.net

B-Model test flight posted:

https://www.youtube.com/watch?v=d3wIesO ... e=youtu.be

Thanks. Those who know--are the fuel flow readings shown instantaneous numbers or an average over some previous time interval? I ask because they seem out of step with the readings:
37.5" MAP, 190 MPH TAS, 6.07 GP
35" MAP, 174 MPH TAS, 7.29 GPH
30" MAP, 162 MPH TAS, 4.78 GPH

Sonex (and Joe!), thanks for the video of the new B-Model (known affectionately as "chubby").

On my MGL w red cube it displays current GPH. I'd love to learn more about the data at 29.9".

How are you getting 4.7gph at 3,200 rpm?
What prop are you using to spin 3,200 at 29" while maintaining 162 tas?
Is the fuel tank larger than 20gal? I see you have 19.9 left after 34min fight time?
You appear to have 62mph tailwind or quarterly headwind (depending on how your MGL is setup indicating the wind direction)...were winds really 62?

I'd love to get those numbers. I'm not even close with my turbo. 2.4 HR flight today to SIU:
7,500 ft w den alt of 9,600:
29.9"
2,970 rpm
5.98 gph
132 TAS

At 31.5" I'm at 6.2 gph, 3,098 rpm and 141 TAS.

What are other flying turbos seeing?

The red Waiex B is using the "cruise" Sensenich prop (56" X 52") at this time I believe. That's what it had on at AirVenture.

My numbers are very similar to yours Josh except I burn a little more fuel. I'm normally running EGTs around 1150-1175 and at 30.0" MAP I will get 3080 rpm down low and 3180 rpm at 8000' MSL. I will burn 6.8-7.0 GPH at that power setting, and see anywhere from 132 mph TAS (down low on a hot summer day) to 148 mph TAS at 8000' on a cold day. Air temperature makes a big difference on my airplane.

I have a 54" X 50" Prince P-Tip on my turbo.

That video was very tasty to watch.....and a real motivator to get it done!!!!

My MGL with the Cube is worthless. Fuel flows fluctuate by 5 gph even if I don't change a damn thing. And Sonex told me they have likewise not had much luck with the accuracy of the Cube. So I would take the fuel numbers with a very large grain of salt.

Mike S- I can appreciate the frustration with the red cube. I originally had similar issues. But I found the issue to be my install and location, not the cube/mgl. And I'm not saying Sonex is wrong, as they are the experts.

But, after doing research, I moved the cube location and then removed some of the flexible line and fitted with AN fittings from the firewall to the fuel filter (cube in between) and have found it to be extremely reliable and accurate. I have done measure testing and its within .05 gph over 2 hours.

Mine no longer fluctuates at all during flight. The only way it did after the install is when a burp was about to occur. The gph would go to 0 momentarily then jump to 8 gph for a moment. I knew the burb would immediately follow.

I have since used fire sleeve to wrap my entire line, even the fuel filter. No issues since.

Imop, a red cube w a vernier assist really improves the performance of the aerovee as you can dial it in for long range cruise.

Who knew a Sonex can be flown hands off! In my old plane you would be doing aerobatics if you tried that.

vigilant104 wrote:Sonex (and Joe!), thanks for the video of the new B-Model (known affectionately as "chubby").

You're welcome. But...Chubby? Really?? Seems a bit backhanded and derogatory to me. I mean, the plane isn't any wider than the original Sonex. It just carries the maximum width farther forward. It certainly doesn't appear "Chubby" to me. Your mileage may vary, I guess.

Oh, and regarding fuel burn, we haven't got the "Gold Cube" dialed in yet. However, I fueled the airplane today, and it took exactly 11 gallons after exactly 2 hours of flight time. So it averaged 5.5 gph over the course of those two hours, which included climbs to 7500 and 8500 msl, some flight at 35 and 37.5 inches MAP, and the rest of the flying at 30 inches MAP. That's right about what we expected, and what we have seen with previous turbo engines.

More testing to come!!

Sonerai13 wrote:

vigilant104 wrote:Sonex (and Joe!), thanks for the video of the new B-Model (known affectionately as "chubby").

You're welcome. But...Chubby? Really?? Seems a bit backhanded and derogatory to me. I mean, the plane isn't any wider than the original Sonex. It just carries the maximum width farther forward. It certainly doesn't appear "Chubby" to me. Your mileage may vary, I guess.

Oh, and regarding fuel burn, we haven't got the "Gold Cube" dialed in yet. However, I fueled the airplane today, and it took exactly 11 gallons after exactly 2 hours of flight time.

Joe,
Thanks for the clarification on the fuel burn. And the "chubby" crack was just in fun, I'm sure the B-model looks just fine.