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My stall speed seems really high...

23.3 at liftoff. How does that jibe with MAP before engine start. That might give you a clue to how much induction loss you are experiencing. Most aircraft lose an inch or more to induction losses. Some RVs do better.

Ed
 
23.3 at liftoff. How does that jibe with MAP before engine start. That might give you a clue to how much induction loss you are experiencing. Most aircraft lose an inch or more to induction losses. Some RVs do better.

Ed
But may I ask what Pressure Altitude that’s at? I’m sitting at 6,900’ at engine start.
 
Sorry it took me all day to reply. I was working with my 88 year old Mom to fabricate an insulated cowl cover for my Rocket. If all goes well, it’ll be finished by tomorrow evening.

I was doing the 24-squared speed runs at 6,400’ MSL. It was a little cooler, so density altitude might have been slightly lower than the 6,400 indicated. I’ve always used the rule of thumb that you lose 1” of manifold pressure for every 1,000’ density altitude above sea level. Both my RV3 and my Rocket seem to do slightly better than the rule of thumb. My RV3 has no filter and straight ram air into the Bendix servo (IO320). My Rocket has a really cool induction system designed and mostly built by Dave Anders with a K&N filter.

Here’s a pic of my induction system… There’s a cone inside the fiberglass structure. Sorry, but I don’t seem to have a pic looking straight in.

IMG_2451.jpeg
 
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