Nosebowls and Temps (Twins)

[Kristin Winter]

After fielding an number of inquiries about warm oil temps and CHT's in twins with various configurations, I am curious as to what everyone's experience is with aftermarket nose bowls.

Did installing either Lopresti or K2U nosebowls cause your oil temps to run warmer? How about CHT's? If so, did you come up with any solutions?

[ComBE]

I installed the Lo presti kit and my cht's dropped 25degrees.

[CLIPCLIP]

i fly 2 twinkys, one with Lopresti, and one with regular nose bowls. i find LoPresti nose bowls will cool the engine better at normal cruise, but the temps will climb much more rapidly than with conventional nose bowls when doing long climbs, slow flight, and other high power high AOA maneuvers for any length of time.

francois

[Kristin Winter]

Thanks Francois, that is good input. I will remember that if I ever think about putting new nose bowls in my aircraft. I am not sure that I am willing to trade a few knots for hotter temperatures in climb.

[N3322G]

Saw huge improvements with LoPresti Cowls and again with new baffles.

Here's the background.

I posted a long time ago that Mom put LoPresti cowls on for the 1992 world race. In 1992, I think she had the first set of production cowls but only Piper stock gauges to assess the change.

As the right seat for 24 years of racing, it was my job to open the cowl flaps if the CHTs got hot. Of course, we didn't want the drag so it was something we watched carefully and only opened when absolutely necessary.

After the LoPresti cowls, there was very noticeable lack-of-need to open the cowls at steep full power climb outs.

Fast forward to 2005 the overhaul of those same engines by Zephyr - went well after two world races - so guess the cowl opening was done appropriately. Put in JPI and noticed engines were running hotter based on needed fuel consumption to keep the engines happy (after break-in). Baffles had been poorly done by the now out-of-business Altus shop. I paid LoPresti to tweak them and ta-da, 20 degrees cooler. It was LoPresti who told me the baffles were put on incorrectly and poorly.

Do open cowl flaps for heat reasons during repetitive practice instrument approaches such as during an IPC but not during any other normal flying.

2008 I noticed the baffles were chewing on the inside of the cowls - only a matter of time before the cowls would be permanently trashed so added Teflon tape at paint shop so I knew I was going to have to invest in baffle replacement in the future.

2009 engines had to have prop strike AD and all of LoPresti baffle improvements were removed. Engines had no prop strike problems but ran hotter again without the removed baffle improvements. I bit the bullet and using Hans Neubert's and Jim Covington's baffles as models, had new Teflon baffles put on. I only have one flight on them but preliminary data shows something on the order of 60 degrees cooler. I wouldn't consider it credible data because it is only one sample but I was quite astonished. Haven't seen anything that cool since the JPI was installed 4 years ago. Watch on here for Belly Meets Blacktop blog starting Dec 9 - by the time it is finished, I should have more experience with the new baffles.

So both cowls and better baffles have can large impacts on keeping Twin engines cooler.

[jeffrey aryan]

Pat,

Do you have the Cowl Flap Extensions on your cowl flaps ?

Do you have the Knots2u Exhaust Fairings or the Standard Piper Fairings ?

I am asking this because I am getting close to installing my LoPresti nose bowls and would like as much information as possible before I tackle this job.

Thanks,

Jeff

[N3322G]

[jeffrey aryan]