Power Flow

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blsewardjr
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Re: Power Flow

Post by blsewardjr »

My Power Flow insert lasted about 600 hours and seven years. Just replaced in April at the annual
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astaib
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Re: Power Flow

Post by astaib »

Rich wrote: Sat Jun 06, 2020 1:19 pm
astaib wrote: Sat Jun 06, 2020 6:37 am Waouh impressive values! Makes me dream.
Unfortunately it is not possible to install PF on the DA40 anymore.
??? Stephen just ordered one.
22245AF6-B25F-4E6B-BE03-BC43958C68A5.png
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Rich
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Re: Power Flow

Post by Rich »

Ah, I see your problem Arnaud. It looks like there was a limited window of time to pull this off in Europe. Bummer. :thumbsd:
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Scottsware
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Re: Power Flow

Post by Scottsware »

I flew this morning and I couldn’t notice any difference in sound or performance with the new insert vs the essentially non-existent insert. From now on I’ll replace the insert as needed but it sure doesn’t seem to make much of a difference. That said I fly out of KAPA and the air is so squirrelly it’s hard to tell about the performance 😂
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OBucher
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Re: Power Flow

Post by OBucher »

Hello,
I am the DA40 owner with the individual STC recognition from the EASA, based on the FAA STC.
At the same time I had also added the electroair ignition. With bad CHT results at cylinder 4 (440F at climb 415 in cruise). The split between 3 and 4 was between 40-50F in cruise and 60F in climb. Now with the electroair removed the temperatures are better (390F in climb - 370 to 400 in cruise). But the split between 3 and 4 is 30-40F in cruise and climb is also there. Cylinder 1 and 2 are insight 10F. For example in cruise 1:360 2:365 3:335 4:380 at 65% and 2200RPM FF appr. 9.2GAL.
Baffles are OK and with new parts built up included “holes” are RTV filled. Maybe it is the fuel line from the fuel pump to the injector. Cause the fuel line is between the oil oil pan and the cylinder 4 near by the cylinder head.
From the performance is the powerflow the better performer than the electroair in normal flight levels. For me between 5000-9000 ft. Also the heater is better than the original exhaust.
Up to now I am happy with the powerflow.
PS: my normal RPM in cruise is from 2000 - 2400 it depends on fast from a to b, or slow around the „church“
Greetings Oliver
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Rich
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Re: Power Flow

Post by Rich »

Scottsware wrote: Sun Jun 07, 2020 8:28 pm I flew this morning and I couldn’t notice any difference in sound or performance with the new insert vs the essentially non-existent insert. From now on I’ll replace the insert as needed but it sure doesn’t seem to make much of a difference. That said I fly out of KAPA and the air is so squirrelly it’s hard to tell about the performance 😂
It's possible that the external sound put out might be mitigated by new inserts but I can't say I recall anything different inside the plane when installing a new one. I don't know how many of you are old enough to recall but installing glass-packs was the thing to do in the 60's and 70's to get a "cooler" sound from your exhaust. They were especially popular mods for big-bore engines and sports cars. There was never any pretext of making the exhaust quieter. Abarth used to do quite well with these things. It would seem to me a solid tube would do at least as well and last longer.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Chris B
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Re: Power Flow

Post by Chris B »

The insert's wound packing tends to disappear by about 200 hrs. It seems like a fresh insert is quieter, but that could be confirmation bias.

We had the Power Flow insert welds fail at about 600 hrs, which ejects the perforated tube. :oops:
Then the exhaust is definitely louder!

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Re: Power Flow

Post by Davestation »

I never thought of it being for sound reduction, that is to say - the entire tailpipe is a muffler, but the glass itself doesn't play a huge role. I believe the perforated tube inside does the sound deadening, and as Chris said, once the glass is burned off this tube will start to overheat and warp and come loose.
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Re: Power Flow

Post by Antoine »

rwtucker wrote: Thu Aug 27, 2015 10:15 pm
Colin wrote:I've never thought about this before. Is there a reason there isn't a SuperCharger that works on the exhaust? It seems like it would be a tiny amount of engine power to turn a fan that created a negative-pressure in the exhaust system. With a simple gate so that it didn't run as too powerful a vacuum. If it is worth tuning the exhaust, wouldn't it be worth turning it into a non-issue?
Really interesting idea Colin!

It prompted me to search for articles related to it. I found this article that covers the main issue we are discussing. http://www.epi-eng.com/piston_engine_te ... nology.htm but I couldn't find anything directly on your point. I wonder if a supercharger could have two isolated vanes; one for intake, a smaller one for exhaust.
Indeed very interesting. Upon harder challenging here's what I see:

- car technology really is at the forefront of vehicle design. Formula one or similar racing are a source of inspiration.
True for engines, structures, crashworthiness and even aerodynamics
- tuned exhaust does the job of scavenging very very well in an aircraft, because the rpm bandwidth is very narrow. A 80/20 solution with very minor weight penalty. Weight being a big negative factor as we all know...
- if one accepts more complexity and weight, one could use variable resonators - as in car exhausts.
- Any more complexity and we'd probably slip into negative return territory...
- On the topic of weight : it is just incredibly sobering to see how any addition to an aircraft meant to increase performance must be challenged based upon its weight penalty. The most striking example is to be found in the ultralight category where a now defunct french company called MCR produced a fixed gear aircraft , the MCR 01 that outran its retractable gear competitors while staying within legal weight limits - unlike the competition.
This remarkable design is reborn as the recently certified Elixir.
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Rich
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Re: Power Flow

Post by Rich »

This is the insert removed today after 9 1/2 years and ~ 460 hours: Removing was a bear. Had to drill out the old screws and cut a groove in the mounting collar to get it out. It was frozen in place, seemingly by a rock-hard buildup of carbon between the mounting flange and the housing. Integrity of the remaining unit was solid:
Powerflow 20200729.jpg
Some remnants of the packing were lurking in a a corner of the muffler housing.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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