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Engine for my CH650b
My kit arrived 3 days ago. I have been sorting inventory of parts. My airline pilot son is making it known that he likes the Jabiru 3300 engine. I would appreciate input on engine choice.
I do have some time, I just got my kit
Also: I need to paint the steel parts and the interior aluminum parts. I'm thinking Zinc Chromate for aluminum, and an Epoxy paint for the steel. Comments?
Replies to This Discussion
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Permalink Reply by Efe Cem Elci
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Congrats Eugene! Are you going for LSA or E-AB certification?
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Permalink Reply by John Austin
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Hi Efe! Your question is a bit confusing - I don't think it's an "either/or" - previously, all EAB's could be built to either comply with LSA regulations or not, depending on the max gross weight. However, unless I misunderstand MOSAIC, the gross weight rule is out and now it is all based on performance-based standards. It would appear to me that it would be difficult to build a 650 that wouldn't qualify as a LSA under the new MOSAIC rules - mo max wt. limit, 650 only has 2 seats, stalls under 59 kts, etc.???
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You're definitely right, John!
Under MOSAIC, the arbitrary 1,320 lb ceiling is replaced by performance-based criteria:
- Stall Speed (Vs1): Maximum clean stall speed of 54 to 59 knots CAS (depending on power-off vs. power-on criteria).
- Maximum Clean Speed (Vh): Removed or expanded based on structural limits (up to 250 knots for clean airframes).
- Capacity: 2 seats maximum (or up to 4 seats for PPL holders, though Sport Pilots are restricted to carrying 1 passenger).
- Engine/Propeller: Allows constant-speed props, electric propulsion, and turbocharged engines
Since the CH 650B naturally has:
- Two seats.
- A clean stall speed well under 54 knots CAS (typically ~40–44 knots depending on load).
- Fixed gear.
Even with a heavier engine, extended 30-gallon wing tanks, a full avionics panel and a higher certified gross weight—will inherently qualify for Sport Pilot operational privileges under MOSAIC while still being registered under the standard Experimental Amateur-Built (E-AB) category.
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Nice to see the FAA get something right for a change! :)))
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Permalink Reply by Ken Ryan
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There were some problems with the early Jabiru engines, but it seems like most of that has been worked out for several years now. However, because the engine is six cylinder carbureted, there can be issues getting temps right. Seems like most builders have to work on that in the beginning, making adjustments to intake and cooling airflows to get it dialed in. My general advice on engines is to not buy too early. It is very easy to think that you are going to actually need the engine a lot sooner than reality. In other words, try to avoid having a new engine just sitting in the shop for several years.
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With the Gen 4, at least in my experience, cooling is NOT an issue! I previously had a late Gen 2 and indeed had to do some tweaks to get the cylinder and oil cooling correct, including tweaking the diverter vanes in the ram air ducts, sealing the ducts where they meet the engine, bigger oil cooler (10-row) etc. However, on the Gen 4, I literally pulled the Gen 4 out of the crate and mounted it, installed the factory-supplied ram air ducts with no adjustments or sealing, went back to a 7-row oil cooler, and the cylinders and oil cooled perfectly ... it was literally "plug n play!" And, this was in a 750 STOL, which is a high-drag/low speed airframe - not the best environment for a 6-cylinder air cooled engine. It should do equally well or better with the reduced drag and higher speeds of the 650. I think the significant difference is that the Gen 4 cylinders are all-aluminum with Nikasil coating vs the earlier cylinders that were aluminum with steel liners. The Gen 4 cools so well I now have to block off about 1/2 the oil cooler in the winter to keep the oil temps up. Even on the hottest summer days, the cylinders run about 270's-280's F with one or two occasionally touching 300-305F - well under the 356F continuous cruise limit.
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Honestly I plan to go with the Viking 195T for my 650
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Permalink Reply by Eugene Steven Reichert
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Wow, can a 650 handle a Viking 195T? I was thinking Viking 140t with a constant speed prop if I can get the money to buy it.
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It does eat away at the useful load and requires batteries to be placed in the tail cone for CG. Oh and just need to respect Vne :)
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