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Prop Change
Posted: Mon Jul 13, 2015 2:49 pm
by DMACJR
Just wanted some insight from those that have "gone before".......I currently have a Sensenich 74/52 prop on my 1950 Cessna 170A and I was contemplating putting a McCauley 76/53 on it (I just got a good deal on an O/H unit as a spare, 8 bolt props are not easy to find for a good price) and I was wondering if I'm going to get any sort of appreciable amount of increased airspeed with installing that prop on my airplane. Currently I turn it at 2350 rpm in cruise (saves fuel) and I get 100-105 mph IAS, with a GPS 112-115 mph ground speed on a no wind day. Thanks in advance for any input you may have.
Re: Prop Change
Posted: Mon Jul 13, 2015 3:01 pm
by lowNslow
My true airspeed was 122mph with the DM7653 prop with fuel flow around 7.5 gph. I replaced my prop with a MDM 7654 and the results are the same.
Re: Prop Change
Posted: Mon Jul 13, 2015 7:47 pm
by ghostflyer
I have used both props , and the sensenich was a better cruise prop and used less fuel . This taken over about 400 hrs each . The sensenich has a thinner profile but the metal was harder and didn't ding as much .
Re: Prop Change
Posted: Mon Jul 13, 2015 8:29 pm
by Bruce Fenstermacher
As the props are different in every way except they are both props legal for the 170, it is hard to know what to expect the differences in performance would be between them. In other words an apple is an apple and an orange is an orange and there isn't much in common except you can eat them both and feel a bit fuller. How much fuller one might make you feel would be difficult to predict.
If is common belief that the Sensenich prop is very close in performance but just not quite up to par with the McCauley though information could be from anecdotal stories. I thought there was one instance of performance numbers given in the owners manual that showed the McCauley to have a slight edge but I can't find that at this moment.
One thing is certain. All the performance numbers are based on the McCauley 76/53 and you should expect to be able to meet those numbers pretty closely should you change the prop. Of course if you did some testing to see how your Sensenich compares, to the numbers then you will know. And you can then share them with us.
Re: Prop Change
Posted: Sat Jul 25, 2015 9:10 pm
by GAHorn
The performance differences between the McCauley and the Sensenich props are found in the Type certificate and definitely favor the McCauley prop.