Pete S-RCU

I have a Byron P-51, it has a Quadra 41 engine.
The problem is it's very loud, as it has a 90 degree straight exhaust pipe.
I need a muffler, but there's only one inch between the engine and firewall.
I know Byron used to make a purr power exhaust, but I've never seen one and I don't think they are around anymore.
Who could make a muffler for this engine?

I'll include a picture to clarify this a little.

JeffH

My Feedback: (43)

You will have to custom make something. the purr-power setup was not used with the 4-Blade reductions system. They used the purr-power mufflers along with the Power-Prop 3 and 4 blade direct drive systemd that used Sachs 4.2 engines.

Pete S-RCU

Thanks Jeff, I wasn't aware of that.

Carlos G

Hi Pete,

There really isn't much room for a decent muffler with the engine in the stock location. I think you would have to reposition the engine forward a bit to gain the clearance for a muffler.

It really boils down to how you want to fly the Mustang. With the four blade reduction system the Mustang will fly so-so but, you wont have much in the way of vertical climb (Can you say "Almost None"? ) and the vibration at idle is very noticeable.

The propeller blades are made of a pliable plastic and are fairly thick cross section wise. So the blades tend to pull down the quadra engine quite a bit while the blade pitch flexes around like old ramen noodles. An electric flyer was doing a conversion thread here a while back and he found the main source of the vibration was due to the pulley the propeller blades are bolted to. He found the plastic pulley-hub would deform and create semi-flat areas between the reinforcement ribs on the backside of the hub. He ended up machining an aluminum vee-groove hub pulley and fitted it to the plastic prop hub.

If you want better performance more in character of a Mustang, then your best bet would be to convert your model to a direct drive and use a good two blade propeller. This would mean a bit of work but, I think you would really enjoy the benefits.

I hope this helps

Carlos G.

kingair70

My Feedback: (156)

There was a Purr Power system offered by Byron for the reduction drive. They offered a conversion kit for the Q35-42 reduction drive as well as a complete new drive unit. This system was designed to attach to the Mustang 50 (Fuji 50) engine that they offered, using the existing drive unit. Although a rare find, the M50 reduction drives are still around if you need to have a muffler installed for field requirements. The other option is to convert the reduction drive that you have to another engine, so that a muffler could be installed. I currently fly mine (10 years old) with a Fox 2.4 converted reduction drive with a Bennett muffler and have no performance issues as stated above (except the vibration at idle). I have attached some pics of both the Fox 2.4 conversion (pics 1 & 2) as well as the factory Byron Mustang 50 reduction drive with Purr Power muffler system (pic 3).