Gp-123

[SupaTim]

Dang, how about now:
[video=youtube_share;FBgN-UEHs0g]http://youtu.be/FBgN-UEHs0g[/video]

 

[bbrown2828]

Wow started 123 for the first time tonight. Man oh man does she have some power. Had a friend over helping me out with it and it almost pulled him to the ground when I went wot

 

[bbrown2828]

[MENTION=335]SupaTim[/MENTION] What rpm you turning

 

[bbrown2828]

looks like a bad place to have a dead stick and not make it back to the runway

 

[SupaTim]

My 123 with a 29x9 is easily 68-6900 on the ground. 6700 on the first run but that number is long gone. On the first one we tested on our Aeroworks Edge, it's a solid 6900-7000 cold...

 

[bbrown2828]

I'm turning 6400 right now

 

[SupaTim]

Get some fuel through it and it'll pick up as you go. Are you running it with the cowl off or buttoned up and ready as it does affect performanc whether anyone wants to admit it or not...

 

[SnowDog]

Does the cowl on improve or detract from the performance, and why? (I'm still learning about gassers)

 

[SupaTim]

It can do both... Inadequate airflow will not only overheat an engine it can "mysteriously" snuff out on engine on takeoff that was running flawlessly on the ground... (has to do with pressurizing a cowl)

A cowled/baffled engine that properly manages airflow will often drop temps by 50+ degrees producing more power and consistent power at that. Think "cold air intake" like the street racer guys are running on their tuners. That being said AIRFLOW is the key word, when running an engine on the ground or even on the stand you're not getting as much airflow as you think.

 

[SnowDog]

So would it be safe to expect that an engine mounted on an airframe with no cowl attached should not overheat?

I've experienced cowl pressurization issues in the past with a GoldWing 68" Su-26 that had a huge open round cowl that I did not baffle...it led to many dead sticks in the air until I figured out what the problem was.