My understanding is that one advantage to using individual throttles as you did was that it mitigated the effect of pulses between the intakes and tuning became less critical.

Where did you get the tubes to weld-up?  I’m planning on making a casting myself but it would nice to know alternate sources.

Bill;

I don’t recall where I got the tube – there are a number of vendors.  I think I bought U-bends which were then cut and welded. The tube size was chosen to have a circumference close to match that of the ports.  The fabricator then made mandrels to shape the tubes to match the ports – then welded into the water-jet cut flange.

 

Al

 

 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Thursday, April 01, 2010 5:06 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Tuned lengths

 

To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Tuned lengths

 

Please post drawings/photos/specs...Yvon

 

Some photos of the intake manifold for the 20B are attached. It is 4.5” from flange to flange; the TB flange is at a slight angle to fit my installation; the TB is TWM 3003; 44mm diameter bores.

 

Another builder built his from my drawings and had a couple extra made.  At least one is still available. The price is around $1000; I’ll have to check. That’s a real deal – by the time I had mine fabricated and heat treated it was over $2000.  Let me know if anyone is interested.

 

Al