Different pitches and repitching

[Cocheret]

I am looking for a propeller for my 170A / 300A as my current one 1A170DM7653 was too short(74 1/4) for overhaul. I understand that I need 1A170 DM7651 or 53. I have found a 7649, a 7655 and a 7654. Would any of these be useable for me, with or without repitching? I know I also can use a C172 (M)DM 7653/55/56, but haven’t found a used one yet.

[GAHorn]

I am looking for a propeller for my 170A / 300A as my current one 1A170DM7653 was too short(74 1/4) for overhaul. I understand that I need 1A170 DM7651 or 53. I have found a 7649, a 7655 and a 7654. Would any of these be useable for me, with or without repitching? I know I also can use a C172 (M)DM 7653/55/56, but haven’t found a used one yet.

If in good condition, either of the 7655 or 7654 would be fine. You will likely experience a very small reduction in RPM due to the larger/longer prop than your condemned one, but either will make a fine prop from cruising. The 7649 would be a good short-field/climb prop.

Caution: Be certain to obtain your new-to-you prop from a reliable source with a believable service history. You do not want to fall for a prop that may have suffered bending/straightening/sold-on-ebay type of scam. A recertification by a pro shop would be a good idea.

[FredL]

Repitching to a climb prop is easy and inexpensive for a prop sh to do. When I had mine repitched to a climb prop it only took a one degree change at the inboard most prop station and all the others were within limits when checked. It only took about 15 minutes.

[Bruce Fenstermacher]

The 49 would be a seaplane prop, flatter then 51 which is usually called a climb prop. The 55 is a cruise prop, the 54 would be between the standard 53 and 55 cruise. This is for a 1A170DM. The 172MDM is a thinner blade prop and the pitch for each step, climb, standard and cruise are about 1" pitch higher.

[ghostflyer]

Buying a second hand prop is like buying a second hand tire. It could have had a number of owners ,been bent /straighten over the years , corrosion inside the hub , totally unbalanced and dury rigged rebalanced and the list goes on. While the fixed pitch prop is harder to disguise its serviceability but with variable pitch props it’s open to abuse.
Buy a serviceable prop from a reputable dealer with a 8130-3 tag and log book. Think about the use a aircraft is going to have , do you need a climb prop or a cruise prop. The MDM props are more efficient due to their thickness but are not as easier to blend out the stone chips . Personally I like Sensenich props due to having a harder skin and resists stone chips . Plus they resist corrosion a little better for some reason.

[GAHorn]

This thread is not asking about Sensenich props, but to expand on that brand, the Sensenich approved for the 170 series is not as good a performer in any regime as opposed to the McCauleys as shown by Cessna’s primary choice AND the performance data published and approved by CAA/FAA.

Secondly, it’s concerning to me that the Sensenich factory has lost it’s own approval basis for making repairs as they have been found deficient/improper in making repairs. That needs to be resolved before I’d recommend a Sensenich. 2-cents

[gfeher]

There's a fair amount of confusion about Sensenich, or I should probably say the Senseniches, as most don't realize that there are two of them (Sensenich Propeller and Sensenich Propeller Service, Inc.), and they are not affiliated with each other. Sensenich Propeller is the manufacturer, headquartered in Florida with manufacturing facilities in Florida (wood and composite props) and Lititz, PA (metal props). My understanding is that Sensenich Propeller (the manufacturer) does not have a repair facility and has not had one for decades. Sensenich Propeller Service, Inc., is the propeller repair service that was spun off from Sensenich Propeller (the manufacturer) about 20-30 years ago, but allowed to use the Sensenich name. It is a completely different company with completely different owners. Sensenich Propeller Service has repair shops in Connecticut, Georgia and Lititz, PA. (Confused yet? I can't imagine how the trademark lawyers allowed both to use the same name. To make things worse, both have facilities at the same airport in Lititz, PA. Plus Sensenich Propeller Services is a McCauley repair facility.)

The Connecticut repair shop of Sensenich Propeller Services was shut down for a while about a year and a half ago, which might be what George is referring to. It had nothing to do with Sensenich Propeller (the manufacturer).

By the way, two interesting facts about Sensenich Propeller (the manufacturer): (1) McCauley is Sensenich Propeller's biggest metal fixed pitch customer, as it makes all of McCauley's fixed-pitch metal props in its Lititz, PA facility. The props are shipped unpainted to McCauley. (2) Sensenich Propeller's biggest market is Airboat propellers. It's about 60% of their business. Who would have thought that there were so many airboats?

My info comes directly from a meeting I had about a year and a half ago with Sensenich Propeller Service's Manager in Lititz, PA (the repair facility), which included a tour of the facility, and a day I spent a little while ago with Sensenich Propeller (the manufacturer) helping with testing of a composite prop. Being curious, I asked questions about the two companies.

[ghostflyer]

Gfeher is spot on with his information on sensenich props. I too have had a look at their facilities and have been indoctrinated. Initially I had a mc Cauley prop fitted [54 in pitch] and it hadn’t had a overhaul since new . I was flying the 170a on a trip twice a week of about 450 miles each way and did that for about 2 years . I really got to know the aircraft characteristics and weather/terrain while flying. Then while away from my home base a rock made its impression on the outer 2ins of the tip of the blade . I blended it out but a vibration had been introduced plus a small twist on the tip that was within limits but the aircraft just didn’t like it. So when back at home the only prop that was available at that time was a sensenich prop plus it was cheap as the the guy who had originally ordered it didnt collect it and he lost his deposit. His loss was my gain as the prop company that was selling it wanted to really get rid of it as it was a slow selling item . So there was nearly 600 hrs running the sensenich prop until my continental stopped turning and it was replaced by a 4 banger. I found the sensenich a very good cruise prop, plus a very stone resistant prop. So when the 4 banger was fitted a sensenich prop went in and been running since . However the MT prop does amazing things these days and would love to know if a member has one fitted to a 4 banger 170. However the pitch on each brand of prop has different characteristics so a 54in pitch on a mc Cauley prop will not be exactly as a sensenich 54in pitch.

PS. At one stage in the end I had 5 different props [8 holers] props in my possession . They are difficult to find in my country and any that came up for sale I would purchase . Many ended up in aero clubs on walls due to not reaching specs, but I was also given a brand new prop still in the waxed paper with paper work . It had been in a box totally away from the elements but the paper work had started to crumble . I have given or sold all my 8 holers prop now.

[GAHorn]

Thanks for clarifying that Gene. The FAA revocation order is described by FAA as applicable to only ONE of the repair facility locations: https://www.faa.gov/news/press_releases ... wsId=23014

And the manufacturing facility offered their own statement here: http://www.sensenich.com/recent-faa-rev ... r-company/

[170C]

Was the Sensenich Propeller manufacturing plant we visited during the Lancaster, PA convention (1993) the one located in Lititz, PA? I remember that being an interesting mfg facility.

[Bruce Fenstermacher]

Was the Sensenich Propeller manufacturing plant we visited during the Lancaster, PA convention (1993) the one located in Lititz, PA? I remember that being an interesting mfg facility.

Both are located in Lititz PA. They are right down the street from each other. The manufacturing facility is not on the Lancaster Airport but very close to it. The propellor service is on the airport property.

I've never toured the manufacturing facility. I've used the Propellor Service twice and it is an interesting place to see.

I imagine if you saw propellors being manufactured in Lititz PA, you toured the manufacturing facility.