Re: Q1 Fuselage comes up

Robert Cringely

I honor your heroic efforts, but my present solution, which is already in hand, sidesteps the crank issue while also raising the thrust line, which direct drive does not. These aren’t inverted Vs, so the prop clearance would be too little with direct drive. 

On Tue, Mar 30, 2021 at 2:45 PM <smeshno1@...> wrote:
 If the crankshaft is in question it should be pretty easy for any decent machine shop to cut a billet for you. The company that Nitrides the crankshafts for Corvair conversions are not outlandishly expensive, not afraid of Experimental aircraft engines (obviuously), and you'd have confidense your crankshaft that would be up to aircraft standard...have them cut all radii to .100". If you have to it is not difficult to clearance cut the rod big ends to accept the wide radii. 

  In my Corvair conversions one of my crankshafts is Standard and was Nitrided from GM.  My other engine I will have to ship to have it cut .010" undersize with the wide radii and then nitrided. Both engines are 2,7L...or..100hp. 

 First thought is the rods should be up to the task. I own an air cooled diesel generator/DC welder that uses a similar basic engine design. tuff as nails! I don't baby it at all and it is always there. Never a hickup.  I've also overhauled many a 1.5/1.6 VW diesel. I had a 1981 VW Caddy that I dropped in a 1.9 turboD (non electronic). The VW's have been successfully used in Europe in Experimental aircraft. The only issues reported is the exhaust odor..pretty ruff on the gizzard in choppy air. Might be a good idea to extend the exhaust pipe further aft.  

 It would be great to chat and to see your powerplant.. JP5 please!! no avgas thank you!!  

 I like titanium also partly because it anodizes very easily and any shade you like..the color stays stable too. Mini turbo..that is too kool!


From: <> on behalf of Robert Cringely <bob@...>
Sent: Tuesday, March 30, 2021 3:48 PM
To: <>
Subject: Re: [Q-List] Q1 Fuselage comes up
I like the idea of using the Briggs & Stratton Vanguard engine, especially since there is so much racing experience and aftermarket parts. I am installing a new engine in my Q1 and going in a similar -- though not identical -- direction. I'm replacing the 22-hp Super-Onan with a pretty generic two-cylinder 870 cc Chinese direct-injection diesel rated for 25 hp at 3600 rpm. I'm turbocharging the engine with a tiny IHI turbo (the smallest sold) and an intercooler. I'm aiming for a turbo-normalized 30 hp, which should give me some really interesting performance numbers at my 17,999-foot cruise altitude.

The engine is all aluminum and air-cooled. I've removed a bunch of extra parts and material like the OEM exhaust, intake, and fuel tank and have the weight down around 55 kg. The new parts are mainly titanium, but that's because we use titanium at my day job and have a welder who does beautiful work. Guessing that the crankshaft is a casting, I'm installing a 1-to-1 belt drive to isolate the prop loads while raising the thrust line. The engine, turbo, and intercooler come from China, the redrive is from India, so the complete powerplant (minus prop) was under $2000 including shipping.

I built the new engine so I can commute to work in San Luis Obispo, CA. My company is right at the airport there and I can even park inside. Presently I fly my Thorp T-18, which takes about 90 minutes for the 222 nm flight from Santa Rosa. I don't expect the Q to go any faster (or slower) than that, but hope to drop the fuel consumption from 10 gallons down to three. Even at 10 gallons it is cheaper to fly than to drive my car, in part because I skip the toll on the Golden Gate Bridge. 

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