Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Webra Speed 40 Q

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Old 02-07-2005, 07:45 PM
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jgroumy
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Default Webra Speed 40 Q

What kind of performance (RPM wise) can I expect from a piped Webra speed 40Q ? Which prop is best ? I'm considering buying a NIB one. Is it a good choice ?

thanks
JG
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Old 02-08-2005, 09:59 AM
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Default RE: Webra Speed 40 Q

Thats the Q500 version. I raced those for a few years.

Its a very good engine. Keep in mind the Q version dynamix carb has no idle mixture or true throttle provisions. It is simply intended as an engine shut-off.

Racing prop of choice was the APC 9x7.5, 8.75x8W or 8.75x7.75W. Your prop will depend on the aircraft it is installed in.

The stock Webra Q-500 muffler had in later years been supplied with an outlet restrictor. It is necessary to use this... the engine needs the backpressure. I also used a larger 8-32 pressure fitting for tank pressure.

Racing with SEMPRA down south, we were allowed to use aftermarket mufflers. Toward the end of their "reign", nearly everyone used the Jett or Nelson mufflers on the Webra .40.

I hope this is helpful.

Bob
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Old 02-08-2005, 10:10 AM
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Default RE: Webra Speed 40 Q

thanks for the info. The engine will go in a Scat-Cat 500. It's intended for fun racing, but i'd still like to go fast... I'll look into those Jett mufflers.

JG
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Old 02-08-2005, 10:34 AM
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Default RE: Webra Speed 40 Q

Perfect application for it.

The stock muffler is ok. Nothing wrong with it as long as the back-end plug is in place.

Enjoy!
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Old 02-09-2005, 08:35 AM
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Default RE: Webra Speed 40 Q

Hi!
The webra .40 Q engine is rather good engine but the MVVS Q-500 are are a bit more powerful...and it has a much better carb with very good idleling capability.
For both these engines 8,75x7, 9x6, 9x7 and 9x6,5 APC are good props.


Regards!
Jan K
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