PROPS  (page four...)

WHAT PROP WHEN FACTORY NEW??? (010201)
Subj: C-125
From: Michael Ward <Michael.Ward6@PSS.Boeing.com>
Jim, I am currently shopping for a Swift and came across a 1946 GC-1B with the C-125 engine and the original fixed pitch prop. This must be a pretty vague question since I don't know if the C-125 came factory with different props for the Swift in 1946. If possible, could you give me some idea of the quality and time before overhaul of these older propellers? Or, is there a web site that you know of that I could research this for myself. Regards, Michael Ward

Michael,
In 1946 the available props were the fixed pitch wood Sensenich and the Aeromatic. I'm not sure when the McCauley became available, but the Sensenich was not approved for the Swift until 1956. The overhaul time is listed in the manufacturers sites: McCauley Propeller Systems <http://www.mccauley.textron.com/home.html> and Sensenich Propeller Mfg. Co. in Lancaster, Pa. USA <http://www.sensenich.com/> (it seems to memory that the overhaul time is 2000 hrs, but I'm not sure) The fixed pitch wood will run until it gets deteriorated from age or water or physical damage. The Aeromatic seems to require attention every one or two hundred hours. The fixed pitch metal props will run forever if they don't acquire stone nicks etc. After 2000 hours they probably need the nicks filed out, profile matching between blades and rebalancing. This process also stress relieves the prop blades. The Sensenich has the best reputation for speed. The McCauley has perhaps the best climb, but there isn't much difference. The wood prop is light, but it won't go very fast. The Aeromatic gets off pretty good, but is slow and the maintenance requirements would make me not want one. --- Jim

MONTY HAS INTERESTING ADVICE ON HOW TO MAINTAIN AEROMATIC PROPS...(010301)
From: Mitch Knox <Mitchell.Knox@PSS.Boeing.com>
I am sorry to bother you, but I am in dire need, I have an Aeromatic and it is for my Stinson, I need the bushings, can you help? Please

Mitch,
Sorry, I got rid of all my Aeromatic stuff years ago. I will cc this to Denis and maybe he will pass it along for the Swift group. I would encourage you to get a Sensenich 74DR-54 prop! -- Jim

OF INTEREST IF YOU HAVE AN AEROMATIC PROP ON YOUR SWIFT...(010401)
From: Charlie Nelson <SwiftlyChs@aol.com>
Subject: Aeromatic Service Bulletin.
Hello Monty; Also, a Mandatory Service Bulletin is out on Aeromatics. In addition the FAA is asking type clubs for response to the "Airworthiness Concern Sheet" per the SB and subject. We need to ask our members still using the Aeromatic to report in. Not many, I am sure. We quit a long time ago and have been advising against using the prop at all. I viewed it as marginal when good maintenance was available. We have until March 5th to respond. Ask any current Aeromatic users to report to us. In use, yes or no, problems, etc. Swiftly; Charlie

Charlie,
I only know of a half dozen or so Swifts with Aeromatics. None of these fly very often. I have often urged people to get rid of Aeromatic props. Usually, the guys that write me back and swear by their Aeromatics have been reading 1940's sales brochures and either have never flown them or have not flown for a long time. -- Jim

AEROMATIC REPAIR SOURCE...(010401)
Subj: Aeromatic prop
From: T.J. Johnson <tj3368k@mmcable.com>
Your source for Aeromatic prop parts is Aero Propeller Company in Hemet, CA, phone 909-765-3178. A word from the voice of experience though....I had my F200 Aeromatic overhauled at a cost of $1500....it lasted 23 hours!!...I sent it back and one blade had 2 lag screws broken..the blade is no longer airworthy....they can't simply replace the lag screws because when the old ones are removed part of the old wood comes out and the new screws will not attain the torque requirement to meet airworthiness requirements.....the wood in the blades is showing their age!!.......Jim's suggestion is a good one..replace the prop....that's what I did. --T.J. Johnson

(Editor says... My two cents. When I became caretaker of Swift N3307K in 1982, it had an Aeromatic prop. It was the variable pitch version not the two position "flip-flop". When the prop started covering the windshield with more than a light film of oil I had it overhauled. Not many hours later it started doing it again. As a starving flight instructor at the time, (come to think of it I still am...), I could not afford to have my Aeromatic overhauled every 20 to 30 hours. Additionally, people knowledgeable on the subject were telling me that the Aeromatic prop blade was inefficient compared to metal props. Efficiency not withstanding, all I knew was I did not have the cash for the care and feeding of that Aeromatic. I sold the prop to an airline pilot (not starving) in Camarillo who also had a variable pitch Aeromatic. He wanted mine as a spare so that while one prop was on his airplane the other was being overhauled. He'd just go on swapping props like that every fifty hours or so... To get me back in the air I bought a fixed pitch metal McCauley prop from the late Gordon Brown in 1983. My cruise speed and rate of climb both improved. That prop is still on my Swift. Meanwhile, retire your Aeromatics. They'll look great all cleaned up and mounted on the wall in your hangar or den...)

YET EVEN MORE BEATING THE DEAD HORSE WITH A PROP... (020201)
Subj: Props
From: Keith Bracht <kab_bjb@skat.net>
Hi Jim, I've been studying the prop section of the Answer Man archives and would appreciate it if you would beat that poor dead horse just one more time. I'm in a real quandary about whether to change to a Sensenich, rework my McCauley or just leave well enough alone. Here are the facts. I have an O-300D with an A crankshaft. I don't know how it got on my airplane, that particular paperwork is long gone. Bill Shepherd and I both feel this is a very strong 145. I have a McCauley 1A170DM7457 which really is 74" and to my knowledge has not been overhauled. She'll turn 2750 and perhaps a bit more on a cool day at 1000'msl. At 2600 rpm and at gross weight (which I'm usually pretty close to most of the time) I get 132 mph . Rate of climb is normally around 750-850 fpm on a cool day at sea level. I'd like better cruise speed, but cannot afford to sacrifice any t/o or climb performance. In fact I would like to gain in those regimes if I can. So, whatta you think? Regards, Keith

Keith, Props are a little bit of black magic. If you just bolt on any prop with certain numbers i.e. 74x58 it may not be equal in all respects to another prop with those same numbers. Under what STC is your engine and prop installed? The Swift Assn. STC calls for a 73"dia. 59" pitch prop. I reworked a McCauley years ago that had those numbers and was the fastest McCauley I have seen. Basically, it was shaved down so the trailing edge was so sharp it was difficult to hand prop and had rounded tips. The tip chord was near the repair limit. I had a prop shop check it over and certify it and they stamped it "MX" - meaning it was at the repair limit and could not be overhauled again. I had another McCauley at the same time which was removed from a Cessna 172 because of damaged tips. I had the tips cut off to give a diameter of 73" and had it pitched to a 59". The first prop would indicate over 160 mph at 2000 msl, full throttle. I put the second prop on and it would indicate 135 mph under identical conditions. Both props were stamped 1A170DM7359! The second prop was more than 1/2" wider in chord at the tip. The Sensenich 74DR-1-62 has a reputation for speed and it will generally be a little faster than a McCauley. I have a McCauley on my airplane right now, but I reworked a Sensenich and had it overhauled last year. I have not been well enough to install it and see how it will perform so it is hanging on the wall of my shop. The old STC that we used to use for installing the Sensenich is not available so I applied for and received a field approval to use it. I also applied for the full STC to use the Sensenich 74DR on any 145, but haven't heard anything back from the FAA. (It's been almost a year now.) Is there anyone who will borrow you a prop? That might give you an idea of which way to go. If you are thinking of reworking your prop, I would reduce the diameter to 73" and pitch it up to a 59". You will have to narrow the tip chord and/or round the tips to allow the engine to turn up on takeoff. My reworked props have always got off the ground well I feel.  --  Jim

PROPS...(020301)
Subj: prop choices
From: Ron Willliamson <rwwilliamson@earthlink.net>
Monty,
I agree with your propeller assessment of Macauley vs Sensenich. When I went up to 145 from 125 Continental years ago, the prop shop delivery boy allowed the repitched prop to slide around in the back of his pickup which dinged the corners of the blades. The shop took it back and had to round off the tips enough to clear the rash and that actually made the prop work better. You may recall I purchased a Sensenich from you for the princely sum of $850 back in 1981 in hopes of doing better with my 145. Alas, when I put it on and ran comparison checks against the Macauley I could gain virtually nothing in speed or climb. I subsequently sold the Sensenich to Bill Whelchel (delivered it in my Swift by strapping it in the passenger seat and flew it up to Watsonville). Don't know what happened to it after that, but I flew the Macauley for a few more years until the 145 expired due to exhaust valve seat failures. It was pitched out to 61 and I could get better gph than Chuck Lischer with his O-320 in 80779. On a 2.5 hour leg, I'd need a couple of gallons less to fill up, flying side by side enroute. Now I'm running the old XL Hartzell on my O-320 and it just beats the air. Great on takeoff to get the full rpm, but it cruises about the same as my 145 and isn't as smooth running. As I get older, I'm convinced that rounder is better! -- Ron

AEROMATIC PROPS...(020401)
Subject: Re: Prop
From: Sara <swiftwks@bellsouth.net>
Jim,
I wanted to see if you might be of some help for one of our customers. We noticed that you wrote @ the Aeromatic Prop in some of the things listed on the Swift page. Gil Schmiel, has a fresh O/H "0" time prop he is interested in selling, do you know what he should price it at? It also has a spinner that will go with it. If you are not sure, do you know of someone I might call to check the value for him. If you need more info, let me know. Thanks Sara

Sara
The Aeromatic props are in a state of limbo right now. There is a bulletin coming out on them and no one knows what it will contain exactly. If it is too restrictive, the Aeromatics will have little value. Having said that, I would kind of like one for the restoration of N2460B, it would make it very original. I would not use it for extended flying - just for display purposes. I am cc'ing the to Denis - he may put it in the GTS Newsletter. The Aeromatic boosters are still enthused about "their" prop - perhaps someone will buy it. -- Jim

MONTY GETS THE SENENICH PROP STC APPROVED...  (090201)
From: Swift31B@aol.com
Subject: Announcement
I got home today and checked the mail. I got my long-awaited STC for the Sensenich prop on the Swift! It took a year and 5 months to get and involved many hours, lots of typing, phone calls and fax messages.

---Description of Type Design Change:
Installation of a Sensenich 74DR-1 propeller in accordance with Installation Instructions Document Number 9, revision 1, dated July 16, 2001 or later FAA approved revision.
---Limitations and Conditions:
Propeller installation for this aircraft limited to the following engine models: Teledyne Continental O-300A, C-145-2, or C-145-2H or O-300B with the propeller control valve secured in the closed position. Model O-300C or O-300D engines with 530860 crankshaft installed.

A separate STC must be used for the engine installation. No specific pitch number is called out, static RPM is not over 2130, not under 2080. This will usually mean a 58 to 62 pitch. (Note there is not a specific pitch requirement.) Diameter not over 73 inches, not under 72 inches. There are 13 pages of stuff in the STC. I am asking $50.00 for the STC, I won't get rich, but it may make the many hours of work more worthwhile!

Jim Montague
3360 Klondike Ave N.
Lake Elmo, MN 55042

SENSENICH APPROVES OF MONTY'S STC... (090201)
Subj: New STC
From: ED Zercher <ez@sensenich.com>
Jim,
I want to thank you for letting us know about the new STC. I am in the process of adding it to our web site and other literature. I would assume that you would like to sell the STC. We offer our STC holders a pretty good deal. The 74DR series propeller has a retail price of $2795.00 less 40% discount to you. You must add UPS shipping charges to this price. The price is for the propeller and the bolt kit. This price is good through 2001. We can drop ship propellers to your customer for no additional charge. If you have any questions, please let me know. Ed Zercher

Ed: Thanks for your reply. I get $50.00 for the use of the STC -- I have already sold 3 of them. If one of my customers wants to buy a new prop, I will make them aware of the fact that I can get a good price on the propeller. -- Jim Montague

(Editor says: It might be corrected by time you go there but if you jump over to the Sensenich site (http://www.sensenich.com/stc/jmgc1b.htm), when they listed Monty's STC they mistakenly put up the wrong email address. The correct address is swift31b@aol.com.)

MONTY GETS A GOOD DEAL ON PROPS... (100101)
From: Jim Montague <Swift31B@aol.com>
Subject: props
Notice
I have been notified by Sensenich that as an STC holder I can get a substantial discount on their propellers. I believe this is on any Sensenich prop, but for sure it is on the 74DR prop for a Swift. It is still more expensive than a used prop, but I can get a 74DR-1 for about $1,800.00 If any Swifters are interested, email me.<Swift31B@aol.com> or call (651)770-5069 Thanks, Jim

SENSENICH PROPS... (100101)
Subject: Re: Sensenich Props
From: Pete Johnson petej@clear.lakes.com
I have seen a lot of publicity lately about your STC for the Sensenich 74DR-1 prop and I wonder about the significance of my M74DR-1-56. As you know, it's flying my C125-2 on 78068. This Sensenich is S/N 16279 reworked by Maxwell 7/92. Do I need your STC?

Pete
That prop is on the original aircraft spec. for the Swift used on the C-125-2 engine. You would only need my STC if you had a 145 hp engine installed. A 74DR-1-56 means it's a DR series, (8 bolt hub) the -1 means it's 74 inches minus 1" or 73" in diameter. The 56 denotes the pitch. Theoretically, the prop screws it's way thru the air 56 inches per revolution. You will only need my STC if you install a 145 hp engine. -- Jim

PROPS...(020302)
Subj: Question
From: Sam Klippert <sam@olypen.com>
Howdy Jim,
Here is another question about Props. I have a MaCauley on my 0-145 and I want to change to a Sensenich. Several Swifters have changed and all are happy they did. My neighbor just bought a Swift project and it came with a DR1-2 it's 73" X 62" with square tips, in a box. I am considering buying the prop, he won't need one for a year or so. I was thinking that it may have too much pitch, that maybe a 60 or 61 would be right. I'm at sea level with no obstacles to clear, and most of our flying is long distance, but ever once in a while we go into a short strip. Thanks for any help or ideas.. Sam Klippert

Sam
I had a 74DR-1-62 on N2334B and I loved it, the cruise was good and takeoff was not too bad either. Pitching that prop to 60 or 61 would not make an appreciable difference. The round tips are only applicable to McCauley props. I have the STC for using the Sensenich 74DR-1 prop on the Swift. I believe the Sensenich 74DR-1-62 is the best all around prop for a 145 hp Swift, the only time it is "too much" prop is when it is new and never shaved down, in which case you may want a little less pitch. You may want to keep your McCauley and temporarily install it for short strip hopping. -- Jim

PROPS...(050302)
Subj: Questions on props - yet again
From: Mark Kadrich <starwizz@pacbell.net>
Jim,
On the subject of beating a dead horse with a prop, (I saw the little sucker twitch a bit :) the 74-DC-0-56 works pretty well. I was disappointed at first but with some testing have come to some numbers. At 2550 RPM I indicate 125. But I climb like a bat! With me, full fuel (35 gallons) and another 200 pounder, on a 75 degree day we climbed out of Reid-Hillview (131') at 1000FPM. This is good because Michelle's only does 125MPH at about the same RPM. I have some other things I want to do to clean up the airplane (like removing the vacuum ventury) to see what kind of effect it has. My question is this, what does rounding the prop tips do? From what I've read, it helps, right? But why? Much thanx in advance, m

Mark
Rounding the tips is a McCauley thing. I don't think the Sensenich repair manual permits that on the 74DR series. The reason rounding the tips or narrowing the blade chord near the tips may be desirable is on a high pitched prop it may "unload" it enough to get good takeoff performance. Most of the pulling on a fixed pitch prop is done at about the 75% station. At high rpm, the tips are not pulling much. The tips do their work on takeoff and a little more rpm increases the thrust considerably. If you remove the venturi and do nothing with the prop, I doubt if you will see much difference. Every bit of drag and weight you can get rid of helps, but if you want to cruise faster than 125 at a reasonable rpm, you will have to get your prop pitch increased. -- Jim

PROP ON O-300D...(060102)
Subj: Propellers
From: Darrel Kester <dskester@worldnet.att.net>
Dear Monty,
Winter is finally over up here in Alaska and I am back to getting my Swift from "Ferryable Status" to being officially airworthy. Loads of paperwork - stc's, deficient 337's etc - the usual story. In the process, I have discovered that the current propeller on my Swift ,which I used to fly from Arizona to Alaska, is not legal. Do you have a listing of the propellers which have been certified one way or other for the 0-300D engine? And while I am writing you, perhaps other Swifters might know of a prop that is available. By the research I have done so far, it seems like a Sensenich is a good option.

Darrel
The O-300D is not the normally approved engine for the Swift. There are plenty of O-300D's in Swifts, installed with the O-300A STC with a field approved deviation for the prop. The McCauley EM series has been used but the Sensenich DC series (74DC-1-60) is a much better performer. My prop STC for the DR series prop includes the O-300D with an "A" crankshaft installed. Is your engine properly signed off? If they used the Swift Association STC SA1-326 and didn't mention the Model O-300D and the different prop it is not. I would suggest you get a field approval for the O-300D and the Sensenich prop. I have several 337's for that combination. The DC series prop is found on some 172s and on Beech Musketeers. If you can't find a used one, as an STC holder, I can get a new one for about $1,900.00, the shipping may be a little more to AK. -- Jim

PROP ON O-360 LYCOMING...(060102)
From: Björn Wendt <Aviatec-Boerny@t-online.de>
Dear "Monty"
We are in the process of doing a Lycoming O-360 conversion for a customers (he is also member of the Swifters) Globe Swift. The STC is listing the old Mc Cauley var. pitch 2D23C53-A/74E-0 prop. As far as we know this prop isn`t available anymore (we tried it nearly everywhere). I heard from several sources that the Hatzell HC-C2YK(R)-1BF/F7666A-2 is now beeing used. Have you heard of any approval of this prop, and if, is there any paperwork available for using it? (our U.S. inspector wants that). A similar problem is also present in getting the Mooney M20A exhaust system. Any help would be appreciated. Thank you, Björn

Bjoern
Yes, I believe that prop is now on the STC. Contact the Swift Association.<swiftlychs@aol.com> Most US 180 conversions use a field approved "equivalent" exhaust system. There is an STCed exhaust system available which claims a horsepower increase. If I can find it advertised I will foreword the information to you. -- Jim

SOUTH AFRICAN SWIFT WING O-300 CRANKSHAFT SOLUTIONS...(060302)
Subj: STC for installation of 8 bolt propeller to 6 bolt crankshaft
From: MBrown@cromedica.com
Dear Monty
Apologies for troubling you again, with this ongoing saga of getting ZS-BCE airborne again! I'm now at the stage of fitting a crank from an 0-300D into my 0-300A engine, effectively making this an 0-300C according to my AMO. This is due to the lack of 0-300A cranks in South Africa, and the fact that I have a prop for the 0-300A mounting, which uses 8 bolts. However, this will require an adaptor plate/extension hub to accommodate the 6 bolt flange on the 0-300D crank. Is there an existing STC for such a conversion, as to develop one locally might be costly/complex, as a once off event? I do realise that the other option would be to find a suitable prop for the 0-300D crank, but these are also not readily available locally! I'd appreciate your advice/assistance. Kind regards Mike

Mike
There is no such STC. The easiest thing to so would be to obtain the appropriate prop for an O-300D. The McCauley 1C172EM7459 has been used, but the Sensenich 74DC-1-60 is a better choice. If you can't locate one of these in South Africa, perhaps a spacer/adaptor could be fabricated, given the latitude of your regulations. I would make it out of chrome moly steel, slightly thicker than the O-300A crankshaft flange unless you have the engineering know-how to calculate the appropriate thickness and alloy for an aluminum spacer. The O-300A bolt pattern would be drilled in the outer edge and the O-300D pattern inboard. This would take very accurate layout and machine work. Good luck! Monty
PS I can get an attractive price on a new Sensenich propeller, but I have no idea of the shipping costs to South Africa.

SCOTT PROVES THE SWIFT WEB SITE HAS NOT BEEN BANNED IN CANADA...(OCT 02)
Subj: Sensenich STC
From: Rich Scott <swiftbird4@aol.com
Hi Jim
I was looking on the swift web site this morning and see that you are the holder of STC#SA149OCH which pertains to the Sensenich prop for the C-145. I am in need of this STC and was wondering how to acquire it. I would also like to thank you for all your excellent effort and help to all of us in the Swift family. Thanks, Rick Scott Swiftbird 4

Rick
Nice to hear from you. Sorry I didn't make Westover. You just send me $50 (US) and I send you the STC paperwork. Also, send me your serial number and registration number. I think you will like my STC, no specific pitch is called out. The operations limitations are in a flight manual supplement - no 125 hp placard. No 2270 rpm placard. You can legally use 2700 rpm. -- Jim

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