Was just asked for help on a weird 20B swap

Yoda · Post by **Yoda** » November 10th, 2006, 4:45 pm

I just had a business associate in South Africa ask me for information to swap a Mazda 20B in place of a big flat 6 in an Atlas Kudu. For those that don't know what a Kudu is it is basically a licensed version of a Aermacchi-Lockheed AL-60. used by the SAAF in the FAC role. Not being a rotary guy, other than knowing how to fabricate a custom engine mount I couldn't really help them out much. but I was able to point them in the direction of a Canadian manufacture of stand alone EFI systems in Western Canada that has experience with this type of swap.

PATDIESEL · Post by **PATDIESEL** » November 11th, 2006, 1:57 am

I don't understand most of what you just typed. Is he putting a 20B into an airplane?

Steve_SK · Post by **Steve_SK** » November 11th, 2006, 6:01 am

I understand quite good, but where's the problem? He just need to make some mounts, some modifications, it is hard to help via internet.

Bolverk · Post by **Bolverk** » November 11th, 2006, 10:59 am

PATDIESEL wrote:I don't understand most of what you just typed. Is he putting a 20B into an airplane?

I am not sure what it is that he wants to put it in, but I do know that rotary engines are used in a lot of planes because of how smooth and small they are.

Steve_SK · Post by **Steve_SK** » November 11th, 2006, 11:30 am

20B is code for Mazda Wankel engine (3-rotor, 3x645 cc I think), it comes from Eunos Cosmo or RX7 FD series (some of them had this engine), very rare and powerful.

Tunes67 · Post by **Tunes67** » November 11th, 2006, 12:53 pm

20B is code for Mazda Wankel engine (3-rotor, 3x645 cc I think), it comes from Eunos Cosmo or RX7 FD series (some of them had this engine), very rare and powerful.

You mean a 20B isnt just a 13B with 7 more B's?

Tunes67

solo_ryder · Post by **solo_ryder** » November 11th, 2006, 1:02 pm

Lol, it goes by liter size. 20B is a 2L 3 rotor and a 13B is a 2 rotor 1.3L. They also have a 4 rotor 27B N/A motor that has 500hp+ stock IIRC.

Yoda · Post by **Yoda** » November 11th, 2006, 4:46 pm

Bolverk wrote:
PATDIESEL wrote:I don't understand most of what you just typed. Is he putting a 20B into an airplane?
I am not sure what it is that he wants to put it in, but I do know that rotary engines are used in a lot of planes because of how smooth and small they are.

The biggest advantage is actually the Hp to weight ratio. The other advantage over the original Lycoming aircooled flat 6 is that they are not prone to thermal shock in flight. I use to right seat in a C337 and the rear engine was always over heating or over cooling and splitting heads. When it comes to air cooled engines personally I am a big fan of round engine. Can't beat a radial. You can loose a complete cylinder rod and piston in flight you can keep flying under power until you decide to land. The coolest radial engine I've ever seen was a small 3 cyl. that was built into the wheel of a motorcycle so basically the engine an wheel were one in the same.

Another engine that is up and coming in the sport plane market might be a cousin to KL V-6. It seems that a couple of aero automotive engine converters in N.Z and western Canada have discovered the Suzuki 2.5 & 2.7 V-6 as a half-pint "Merlin" for the rapidly expanding sport plane market.

Tunes67 · Post by **Tunes67** » November 11th, 2006, 6:17 pm

Lol, it goes by liter size. 20B is a 2L 3 rotor and a 13B is a 2 rotor 1.3L. They also have a 4 rotor 27B N/A motor that has 500hp+ stock IIRC.

Hmmm.. seems to me you get one rotor for every 7 B's.

Jesus I need a new hobby

Tunes67

PATDIESEL · Post by **PATDIESEL** » November 12th, 2006, 10:14 pm

LOL, I know what a 20B is guys. I was asking what he was putting it into. Vaughn said, if you don't know what a Kudu is, it is kinda like a Lockheed somethingsomething... Since I didn't know what either were, but know who Lockheed is I assumed an airplane, which would make sense b/c of the size and power of a rotary. Also, the maintenance isn't as much of an issue since air planes have a much higher maintenance requirement than autos do. It is just funny to me that in all the years I've been reading Vaughn's posts I cannot tell what he is talking about half the time. LOL.
On the subject of rotaries, there is a 27B, but they are custom made engines. Not built by Mazda and widely used in prototype Mazda powered cars. I've seen several and there is a manufacturer about 20 minutes from my house that makes the Hans device, but who got his start racing Mazda powered 27, 20, and 13B rotaries. His name is Jim Downing if interested in looking him up. His staff are gods at tuning rotary related engines and ECMs. Luckily for him the Hans has become standard equipment in most pro race cars and thus he is making a fortune. His Mazda racing career was in serious decline. He was also the inventor of one of Mazda's most winningest prototype chasis. The Kudzu was a great chasis, but outlawed in some forms and not enough safety testing in onthers prohibited it. This is not to be confused with the Kudu plane Vaughn was talking about which was the source of my confusion. I thought he might be talking about a Kudzu, but since he also mentioned Lockheed in the same breath, it only made things worse.

Yoda · Post by **Yoda** » November 13th, 2006, 10:43 pm

Actually a real Kudu is a small antelope like a impala, eland, or gazelle.

This is the Kudu I am talking about.

An EFI engine should really improve the performance of this aircraft especially since it is already flying out of strip at 6000ft. Thanks of the tip on the rotary tuning shop down your way. Building an engine for an aircraft is not quite the same as for a performance car. Usually the big HP numbers are sacifaced for maximum reliability and minimum weight. Also make a most amount of torque at the lowest possible rpm is important. You can't swing a prop to fast otherwise the tip speed can go supersonic and brake the blades apart. The only plane in the world where the tip of the prop were designed to go super sonic was the Russian Tu-95 Bear bomber.

Years ago some of us older MX-3er were working on a completely bolt in supercharger kit that would were on the V-6 and well as the 4 cyl cars. At the time there were problems with the S/C compressor we were using. It was originally design for an aeromotive purpose and although the size of the A/C compressor the biggest issue was lubrication so the project was shelved. The latest version of this S/C addressed these issues building a pump into the S/C. I finally completed the kit and test fitted it to both the V-6 and B6/BP. Everything bolts up completely and pulleys line up on both type of blocks. Even about 50% of the I/C and intake plumbing can be used on either type of engine. After talking to the guys down in South Africa I been considering selling the S/C and mounting brackets to them since it should be a direct bolt on to the 20B as well since it also uses the same A/C compressor and there is not enough of a market these days for the 323/MX-3/ Protege to make it financially worthwhile anymore and market is getting smaller everyday. Back in 1999/2000 when the project was first prototyped it might have had a chance. Looks like this S/C might be making a full circle and started like in the air and ending in the air.