Borer Prop

[sophistical]

I'm thinking of getting a Borer (McCauley 1A175GM) via Svenn's STC. (http://www.svennsaviation.com/page6.html)

It appears the pitch allowed varies between 40" to 45", what does everyone recommend as the best compromise between cruise and climb for a150 hp Pacer? Also, anyone have a Borer they are willing to get rid of?

[PACERGUY]

When you hang that big Borer on be prepared to loose 15mph off the top depending on what your old prop was. I ran a 80inch with a 45 pitch and lost 15 mph. It is just the price you pay for getting off the ground quicker. I don't think it is a compromise as much as just suck it up for the better take off.
DENNY

[sophistical]

Yes, Pacerguy, I'm expecting a significant drop in cruise. I'm only cruising at 110-115 at 2450rpm today with my 58 pitch and 8.5 tires which seems to already be slow compared to others so hopefully I can stay about 100mph. I am just wondering if there is a much difference between a 40" and a 45" for takeoff and cruise. On our stock props it seems that there is a significant difference between say 57 and 60 so I was wondering if others see that same difference on the borer or does there not seem to be much difference on that prop?

Also, what does cutting it down from 82 to 80.5 (allowed by the STC) make a difference at all? I imagine it could impact how loud it is.

[Fisherman]

On floats 41 or 42 inch and on wheels use 43 or 44 inch. Colin

[sophistical]

Great! I'll be looking for the 43 or 44 as I'm on wheels.

[highroad]

I had a 41 pitch on my 160hp that worked well but I was on 31'' bw's and uncovered gear so it was already slow. I planned 100mph at 2500rpm cruise at 9gph. But, I wondered what a little more pitch might do for it. The airplane struggled with load at higher altitude, mostly because of all the drag I suspect, but it felt like a little more pitch in the prop might of helped get the wing on "step." I would probably start with a 43'' and pitch down if needed.

Brent

[Fisherman]

I always install a manifold pressure gage in my airplanes so I can tell how much power my engine is developing. When landing on a high elevation lake I always climb the airplane and set my mixture for maximum power and shut down the engine with the mag switch. When I start up I have maximum hp for take off. The manifold pressure gage can also be used to determine how much load the propeller is pulling. A Borer Prop will have lower manifold pressure at the same rpm as the old shorter prop and I always run higher rpm on the borer with the same fuel burn and better cruse speed.

[highroad]

I always install a manifold pressure gage in my airplanes so I can tell how much power my engine is developing. When landing on a high elevation lake I always climb the airplane and set my mixture for maximum power and shut down the engine with the mag switch. When I start up I have maximum hp for take off. The manifold pressure gage can also be used to determine how much load the propeller is pulling. A Borer Prop will have lower manifold pressure at the same rpm as the old shorter prop and I always run higher rpm on the borer with the same fuel burn and better cruse speed.

Great points! I do wish I had had a Manifold pressure gauge in the Pacer, as this would of told more of the story.

Interesting concept on setting max power then shutting down with the mags........
I just had an interesting experience in my Maule over in Idaho. We got snowed in for 3 days at Cold Meadows and when the window came to leave, we had to depart at 7100ft msl with 6'' of wet snow and mud underneath. It took all she had to get us out of there, even on 35'' bushwheels. But, I had the advantage of being able to stop and find max power (wasn't worried about sucking stuff up in the prop due to all the snow cover) but on floats, that would not be very easy to do...........

[Fisherman]

Floats are not much different from wheels or skies, in that it is hard to get high enough rpm to set your mixture when you are not flying because there is a good chance you could pull rocks or water into your long prop.[lot less chance with snow] I always mark or pick a spot that is no go on a short lake and heavy snow on skies when taking off, so I know what you are talking about with 6 inch of wet snow. Even on floats you should always remember, even on a short lake when you want to get off as soon as possible, that if you apply power too fast you could damage the long prop from the water spay. Once you get moving with a little forward speed on wheels or floats there is a lot less chance of damaging your prop.

[nicka]

I have an 82/44 borer, 150hp, 26" Goodyears, uncovered gear and cruise at 106mph, in the winter in really cold air it will sneak up to about 113 mph, but consistently cruises 106mph.