Hi there,

Bob White gave me this address to subscribe to a mail list about rotary
engines in aircraft.I'm building a BD-4C and am planning to use a
Mazda rotary (20B hopefully).Please subscribe me to your list.

Regards,

Tony King
Queensland Australia

Hi Tony,
Welcome aboard. Too bad you are in Queensland. I am in the process of
heading out to Perth from California. We have a rather fair size
group of aviation
rotor heads in Perth. The newsletter will be uploading some pictures
of the Perth guys building rotary powered airplanes in the next
three weeks.

The 20B might be a bit much for a BD4.
Where in Queensland do you live?

Paul Lamar


Hi Paul,

I'm on the western outskirts of Brisbane at a place called Karana
Downs.Thanks for your advice on the engine choice.The BD-4C calls
for 180 - 300 hp.I'm aiming for 200 - 250 hp.From what I've been
reading - including your excellent website - I had concluded that's a
touch over a typical 13B's output and the budget won't stretch to a
Renesis.I was assuming a 20B would deliver around 250hp without too
much difficulty.But if a 13B can reliably deliver in that range that's
great - much easier to find and less weight.

I look forward to learning heaps from the mailing list members.

Regards,

Tony

As long as the 400 pound 20B engine FWF weight won't bother you it
is OK.
A P-port 13B with a 2.85:1 gear box will be right around
250 HP at 7500 RPM for take off and firewall forward weight
will be close to 300 pounds. It would be a lot cheaper. I don't know
about Aus but 20B's in the states are going for up to $8000.

Paul Lamar

Hi Paul,

250hp for takeoff sounds fine to me.I hadn't realised a 13B could get
to that.Is the P-port a specific model or can any 13B be configured
that way?20Bs are pretty scarce in Oz.I think the last one I saw was
about $12K.Renesis motors seem to go for about $18K+.An RX7 half cut
seems to be around $3K - $4K.

Weight is one of the big reasons I'm leaning towards a rotary.I want
the power but I also want to maximise the useful load.

Thanks for your advice.

Regards,

Tony

Its a minor mod to any rotor housing but it makes the intake manifold
much easier to build. Just a couple of two inch tube bends. Saves a bit of
weight over a cast aluminum intake manifold and slightly less fuel burn.
Can you over haul your own engine?

Here is a utube video on the subject.

http://www.youtube.com/watch?v=LkKw72dZ2yc
http://www.rotaryeng.net/Welded-steel-p-port.html

Paul Lamar