PROPS  (page FIVE...)

SOME GOOD QUESTIONS FROM A NEW SWIFT CARETAKER...(NOV 02)
Subj: Hi Monty
From: Tom Yoder <tryoderjr@aol.com>
Hi Monty, I contacted you a few weeks ago about N33TC.......she currently has a new KLIP-TIP 73-54 installed...the old owner needed the climb prop to operate from mountainous terrain in GA....however in Houston the only thing I have to watch out for is the occasional 4 wheeler with ridiculous tires.....so what would you recommend for a reasonable cruise prop..I plan to do limited acrobatics and mostly straight and level flying...I have read your archives and it would appear that somewhere around 58 or 60 might be the right pitch...and perhaps have the prop tips rounded....  Thanks in advance for you assistance....one of the biggest factors in helping me to justify my purchase was how nice everyone associated with swifts seems to be. Respectfully, Tom Yoder >>

Tom
When talking about a 58 or 60 pitch and rounded tips I am referring to a C-145 or 0-300 engine. A C-125 will just barely pull a 60 pitch prop. If you want any reasonable climb performance at all I would stick to what you have. If cruise is important, the highest pitch for a C-125 is usually a 59 with 57 preferred. 3. -- Jim

NEWS FLASH!!! (APRIL 03)
From: Jim Montague <Swift31B@aol.com>
Subject: News Flash
Denis
I got word from the FAA today that my revision of STC SA1-326 would be approved. I haven't got a copy back from them yet, but it will include all C-145, O-300A, B, C, D and E engines along with McCauley 1A170/DM, Sensenich 74DR-1 and Sensenich DC-1 props. Also the 530582 (Carburetor Intake Housing) this may seem like a small point but has been a source of contention several times. Red line is now 2700 rpm. -- Jim

PROP PITCH... (APRIL 03)
Subject: Re: prop pitch
From: Porter Houston <porter.houston@comcast.net>
Monty,
I saw in the news letter about the STC revisions. But it also mentioned a restriction on the prop pitch. What dia/pitch is allowed per the 145hp STC.
Porter

Porter
On the Swift Assoc. SA1-326 the minimum pitch is 59" for either the Sensenich or McCauley props. I had a hell of a time with the FAA on that. I did get the maximum static rpm raised to 2250 rpm. BTW - the max. pitch is only limited by the mfg. specs, which is 66" or 68", I forget which, and the min. static rpm which is 2000. On my Sensenich prop STC I did not mention a minimum pitch and got it by. I think you have the Merlyn GW STC which allows a 58" pitch. I have applied for another STC which will allow 76" dia. props with the pitch as low as 51". I am dealing with the Chicago Certification Office on this one. We'll see if I get it. -- Jim

VIBRATION RESONATES... (MAY 03)
Subj: prop
From: Don Woodhams <biplane1@earthlink.net>
Hi Monty, I have N3866K (form Mark) and installed an 0300A OH engine. The prop is a M74DR-1-58 and turned too high so had it repitched to 60. Works great but now I have a vibration, resonance, like in aircraft that have placarded RPMs. Its about 1400 and again at 2100. The prop was indexed at one blade edge at T/C I tried 180, and one bolt in each direction no help. I looked through all your letters on props and found nothing on this condition. Oh yea, I tried my (0 time) Aeromatic it was smooth, no guts or I would leave it on. Thanks Don Woodhams

Don
It sounds like your pitch is off a little on one blade or the balance is off. Either condition means you need to take the prop off and return it to the prop shop. Cessna published a letter back on 7-8-53 about advancing the prop index TWO holes, effectively a 45 degree advance. -- Jim

ENGINE/PROP COMBO QUESTIONS... (MAY 03)
Subj: O300/prop combination
From: Harry Fenton <Harry.Fenton@unison.ae.ge.com>
Hi Jim,
I've got some questions about engine /prop combos. I think that I've got it figured out, but I want to clarify some things with you. * Is the same model Sensenich prop, albeit different pitch, used on the C125 and C145/0300 with 8 bolt cranks? * It looks like the DR prop is for 8 bolt cranks and the DC series is for six bolt cranks. Correct? * I have an O300D, is there a Sensenich prop approved for the six bolt crank specifically for the Swift or is a 172 prop modified for use with the Swift? I see that you recommend a Sensenich 74DC-1-60- is this prop ready to go or does it need to be pitched for the Swift? It looks to me like it would need to be cut down to a length between 73" to 72". * I have some info on the Sensenich STC that you hold for the 145/O300 engines. The D is referenced, but it stipulates that a 530860 crank needs to be used. As far as I can tell, the 530860 is the crank for the O300A. Is there an STC to convert the D to the 530860 crank? * Theoretically speaking, is it possible to build an O300A with the O300D accessory package to include the vacuum pump? Overall, here is the problem: I can build an A or a D engine with parts that I have. I would prefer the D due to the vacuum pump. I have several new and yellow tagged vacuum instruments and pumps, so I don't want to spend the money on an electric gyro. The C125 on the plane that I'm buying is equipped with an Aeromatic and the engine was overhauled 45 years ago. The Aeromatic is not likely to be satisfactory in the long run, so installing a Sensenich is a given. While the engine is low hours, my experience is that it really should be opened and inspected to clear any doubts about its condition . If nothing else, all of the gaskets would need to be replaced to stop oil leaks. So, if I'm building an engine, I might as well put the time and effort into the O300 in my shop and tinker with the C125 as I can. At your convenience drop an e-mail back or give me a call. Thanks, Harry Fenton

Harry
The revised STC SA1-326 held by the Swift Museum Foundation allows the O-300D with the 74DC-1-60 prop. Yes, my Sensenich prop STC is only for the DR prop, so if you use it on an O-300D you must install an O-300A crankshaft. The C-125, C-145, O-300A and O-300B all use the 8 bolt DR prop. A 125 will just barely pull a 60 inch pitch prop but it will, although takeoff and climb are not very good. Yes, the O-300C and D use the 6 bolt DC prop. To install the 530860 crankshaft in an O-300D my STC will do for data. TCM has written letters calling that a minor change akin to installing a taper shaft or a flange shaft in a C-85. You cannot install the vacuum pump on an O-300A, you need the "D" starter drive. You cannot just put the "D" starter drive on an "A", there is an oil passage in the "D" case for the starter shaftgear. My suggestion would be to build the O-300D and use the revised STC SA1-326 with the Sensenich 74DC-1-60 prop. In the meantime, just enjoy flying the old C-125, it may run longer than you might think. -- Jim

AND HERE’S THE PITCH...(JUNE 03)
Subj: Prop pitch for C125
From: Harry Fenton <hlfenton@charter.net>
Hi Jim,
I'm going to have the McCauley on the C125 re-pitched. It's a 59 pitch right now and Mark Holliday has suggested a 55 or 56 pitch and I see that you also have mentioned a 55 or 56 in the archive. Any guess as to the performance difference between a 55 or 56? I'm guessing that the prop can only be twisted from the base pitch by only so many inches, also, so that limit may dictate what I can do. By the way, I'm working off of 2500 turf with 50' obstacle at the south end and clear approaches from the north. The 59 is making a Swift pilot out of me as I've really had milk every bit of climb out of it to take off to the south. An interesting side note: The engine turns up to 2500 rpm and 28" with the 59. I put the Aeromatic on and it gave me about 200 fpm climb more than the McCauley and popped off the ground in about 300 feet less. The Aeromatic definitely felt stronger and smoother too. RPM really wags around with pitch change, though. I'm really having a good time with 78627- I've got about five hours on it since I picked it up on Monday. Thanks, Harry Fenton

Harry
A 55" pitch would help your climb. You can see the original Aircraft Spec. with the optional props on the Swift site. The diameter can be 71.5 min for a 125, I wouldn't necessarily reduce the diameter, but rounded tips on a McCauley seem to help. I wouldn't be too concerned with pitch change limits going from a 59" down to a 55". Red line for a 125 is 2550, if all you can get is 2500, you definitely need less pitch. If you intend to use that same prop on a 145 later you will want a 59" pitch. -- Jim

JUST BECAUSE A SWIFT LOOKS FAST DOESN’T MEANT IT CAN GO FAST... (JUNE 03)
Subj: C-145 prop
From: Nick Goodman <frh@bluemarble.net>
I have installed the 1A170DM7357 on the swift. It definately makes a difference, but I still feel like I should be turning more rpm with that prop. I am now getting around 2200 static and 2300 on climb 80 IAS. The speed really sucks! I am only cruising around 115 at 23 squared. What would I do if I put on a cruise prop? I would probably need a catapult to get off the ground. I do have a nice AEIO-360 sitting here. Maybe it is just time for an engine upgrade. :-)

Nick
If you put in a 200 hp engine and cruised it at 50% power it still might only indicate 115! With a 145 hp engine at 23 square you are only using about 95 hp. (65% power). At the risk of sounding like a broken record....to make a 145 with a McCauley go, you need a 73x59 with narrowed tips, preferably rounded and you must use 2500 - 2600 rpm at 23" - 24" mp. (75 - 80% power) I use 100 mph for climb, it allows the rpm to come up a little and cools better too. There is no law against using 80% power, you just must watch the engine temps. I just put on a Sensenich 74DR-1-62. I anticipate a cruise of 145. -- Jim

MONTY HAS INFO ON HARTZELL PROP AD... (JULY 03)
AD 97-18-02 R1
The above AD only affects the old steel hub propellers -- the "HC" and "HA" series. Example - the HC-82XL used on the 150 hp Swift. It's not often that an AD note is good news but this one gives terminating action for AD 97-18-02. By modification to model "MV" configuration the AD is terminated. The "MV" series propellers are direct replacements and approval is by Hartzell Service Bulletin so there should be no paperwork problem. -- James J Montague A&P IA
p.s. AD 97-18-02 also applies to certain old BHC series props that have blade clamps.

MONTY’S "LONG PROP" STC... (JULY 03)
From: Jim Montague <Swift31B@aol.com>Subject: Possible Prop STC
Swifters
I recently applied for an STC to use the longer fixed pitch props on the Swift, the 76" dia. McCauley DM and MDM series and the Sensenich 74DR and 74DC series. By using the Part 23 criteria I get by the diameter problem. These props are not for everyone or every application but for mountain flying or short strips they would be nice. I have got to the point where I would have to spend some money for a DAR and some flight testing. I would like to poll the Swift owners and see who might be interested in such an STC. Obviously, if no one or just a few guys are interested it would not be practical or very smart to spend a thousand bucks on this. If 10 people might be interested at $100 ea. I could at least break even. Jim Montague <swift31B@aol.com>

HARRY IS REALLY GETTING INTO THIS PROPELLER DEAL... (JULY 03)
Subj: Prop performance numbers

From: Harry Fenton <Harry.Fenton@unison.ae.ge.com>
Hi Jim,
Here are some interesting comparative numbers between a fixed pitch McCauley and an Aeromatic installed on a C125. The tests were conducted on days of similar temperature and humidity, aircraft loading, but have not been corrected to density altitude, so the numbers are snapshot in time. Despite the subjective numbers, the trend and performance feel was clearly evident, so the numbers are close enough to draw a general conclusion. I also used an electronic optical tachometer as the cable driven one in the plane was inaccurate by a hundred RPM or so. The airspeed and VSI in my plane are a bit inaccurate, so I used GPS, a stopwatch and the local controllers to help give me an altitude read from the encoder.

Aeromatic
Static RPM/MP@750' MSL 2500@27"
In-flight Max RPM/MP/IAS@5000 feet 2550@27" 135 mph
Cruise RPM/MP/IAS@5000 feet 2450@23" 125 mph
ROC/half fuel/85F 500fpm solo/350 two pax
Takeoff run 1250' on turf

McCauley
71.5 diameter, 59 pitch
Static RPM/MP@750' MSL 2450@28"
In-flight Max RPM/MP/IAS@5000 feet 2500@27" 145 mph
Cruise RPM/MP/IAS@5000 feet 2425@23" 140 mph
ROC/half fuel/85F 450 fpm solo/ 300 fpm two pax
Takeoff run 1350' on turf

71.5 diameter, 55 pitch
Static RPM/MP@750' MSL 2550@28"
In-flight max RPM/MP/IAS 3000@28" 150 mph
Cruise RPM/MP/IAS 2650@22" 142 mph
Cruise RPM/MPIAS 2550@21" 135 mph
ROC/half fuel/85F 750 fpm solo/ 500 fpm two pax
Takeoff run 1100' on turf

Clearly, the climb pitch 55" McCauley works better than the Aeromatic, even providing better cruise performance on the C125 than the 59" "cruise" prop. Granted, the engine is turning higher rpm with the climb 55, but the power is produced at a lower manifold pressure, so theoretically, the engine is not working as hard as with the cruise 59. The 55 clearly accelerates better and just seems to allow the engine to develop more pull. In relation to the Aeromatic, the 55 McCauley turns the same airspeed at 2"-3" less manifold pressure, and cruises as fast as the 59 McCauley at an inch less manifold pressure (although at a couple of hundred more RPM). The negative to the 55 is that it is very, very easy to run the engine up to 3000 rpm especially when descending. I now understand why 56" was suggested as a pitch as 55" is more likely to over-rev the engine.

Another observation on the current 55/C125 combo is the initial rate of climb right after takeoff is about 750 fpm, but, with the gear retracted, cleaned up and trimmed for 85 mph, the rate of climb increased to 1100 fpm, and stabilized at about 950-1000 fpm through 4000 feet, and then drops to about 850 fpm, through 5500 feet, slowly tapering off to about 500 fpm up through 10,000 feet. The C125 Swift is still not a rocket ship on takeoff, but it goes pretty well when it is cleaned up.

I would not recommend the 55 to anyone operating a light case C125, if any light case remain in service. The RPM and torsional vibration increase will make short work of a light case. Even the way I'm running I would urge caution in turning the engine much beyond 2700 RPM on a stock heavy case engine. The high RPM is not a free ride in that the center bearings take a beating and the torsional loading, or twist, on the crankshaft increases. I'm going to keep tinkering and I'll report back on some cruise numbers at altitudes about 5,000 feet. -- Harry

PROP vs STC... (AUG 03)
From: Ross Warner <Meyersswift@cs.com>
Hello Jim, Sorry for the late response to your inquire to the membership concerning interest in the STC for the Sensenich 74DC props. I happen to own a Sensenich 74DC-0-56 prop for N2386B with the O-300-D engine and I would be most interested in making the paper work right so please count me in. E-mail with details. Ross Warner

Ross
The STC that I hold is for the 74DR-1 prop. The STC you want is SA1-326 (revised) from the Swift Museum Foundation. Just one thing, the Swift Museum Foundation's STC is for (among others) a 74DC-1-59, so you would need to get it shortened 1" and pitched up 3" at a prop shop. I am trying to get another STC for the 74" prop but that may be a long way off. Also, the FAA probably will want more pitch than 56" to avoid exceeding the 125 hp limitation. The Swift Museum Foundation gets $100 for the revised STC, if you have the old version, they allow you a $50 credit for it. -- Jim

THE NEVER ENDING QUEST FOR THE EFFICIENT PROP... (OCT 03)
From: Steve Wilson <SteveWlson@aol.com>
Subject: Prop Efficiency Calculator
Denis... Here is a link some might find interesting...
http://www.pponk.com/HTML%20PAGES/propcalc.html

PAINTING PROPS... (NOV 03)
From: Keoki Gray <jankeoki28@aol.com>
Subject: Prop paint
To: williambulger@msn.com
Cc: Swift31B@aol.com, arbeau@napanet.net
Hello, Bill,
Another Swift fan here. I just went through an educational experience with the prop on our Pitts, and thought it might be of interest. We had a polished Hartzell prop. Since we live so close to the coast (the airport is less than 1 NM from the Atlantic), it was impossible to stay ahead of the leading edge corrosion. Since the prop was near limits and was starting to surge, we lost confidence in it and the decision was made to buy a new prop. Hartzell said they would happily supply us with one, but that the only finish we could get was the standard Hartzell gray paint/white tip stripes. (During the last overhaul of the polished prop, the prop shop said they would be happy to paint it at no extra charge after removing the corrosion, but they would not polish it.) You mentioned in your e-mail to the Swift site that you had never seen a painted Hartzell, but they are in the majority. And from our experience I would strongly recommend a thorough removal of every trace of corrosion followed by a really good coat of paint. It will be better for your prop and a lot less hassle and maintenance for you. Hope this isn't too preachy, but I wanted you to benefit from our history. Thanks and fly safely, Keoki Gray

PROP TESTING IN THE MINNESOTA SNOW... (DEC 03)
Subj: Re: Prop numbers
From: Mick Supina <masupina@mmm.com>
Jim, I finally got up and tried out the new prop this afternoon. It went well and it seems smooth to me. The vibration is about the same as with your prop.

I took some readings:
A 23 inches of manifold pressure and ~2600 RPM: N: 127 E: 187 W: 125 S: 175 Average: 154
A 22 inches and ~2550 RPM: N: 116 E: 184 W: 111 S: 174 Average: 146
At 20" and ~2500 RPM: N: 115 E: 181 W: 110 S: 167 Average: 143

I also checked the Tach time versus my watch for 30 minutes during the flight. It was really close. Of course, I did not check it from start of plane until shutdown - just 30 minutes during the flight. I'll try to get an entire flight from start to finish sometime soon for comparison. Thanks for helping me out of the snow drifts today!! -- Mick Supina

PROP/ENGINE SPEED TESTING... (JAN 04)
Subj: Prop / Engine Speed Testing
From: Pete Johnson <petej@lakes.com>
Happy New Year, Jim!
Following the lead of Mike Supina with his prop testing report to you earlier in December, I took 78068 out for a few square rides to check speeds and here's what I got. 0-300A, 22hr SMOH, with a Sensenich M74DR-1-58 prop. At 3500 feet msl, -4 C on the surface, 30.80 barometric pressure, 140 degree oil temp - MP 24 inches, 2650 rpm: N - 139 E - 155 S- 141 W- 130 Avg. 141 MPH. MP 26.5 inches, 2700 rpm: N - 146 E - 159 S - 151 W - 136 Avg. 148 MPH. What do you think the numbers might be with a 59 inch prop? All the best to the Montague family for the Holidays! PJ

Pete
A 59 pitch would not make much difference. There is nothing wrong with your numbers! -- Jim

PROP STC...(FEB 04)
Subj: 0-300d
From: Todd Asche <wcrcoi@midstate.tds.net>
JIM,
GOOD MORNING FROM WILLMAR, ABOUT 6" TO 8" OF SNOW THIS MORNING AND STILL COMING DOWN. BOUGHT A 0-300D ENGINE THAT NEEDS THE BOTTOM END OVERHAULED. ORDERED THE STC FROM SWIFT PARTS, ($100.00 WHAT A BARGAIN) THE GAL THAT ANSWERED THE PHONE WAS GOING TO MAIL IT OUT TODAY. SHE WAS NOT SURE WHICH MODEL PROP WAS USED WITH THIS STC WITHOUT ASKING SOMEONE. SO I THOUGH I WOULD JUST CHECK WITH YOU. QUESTIONS: WHAT MODEL PROP CAN I USE. CAN I USE MY OLD SPINNER AND BACKER PLATE OFF MY SENSENICH MODEL 74DR-0-58-1 THAT WAS ON MY PLANE? I WOULD LIKE TO FIND A USED PROP? IF NOT, CAN YOU GET A NEW ONE FOR ME? PRICE? THANKS TODD FROM WILLMAR

Todd
Yes, that is STC SA1-326 (revised). It was just for the O-300A and I got it revised to include all O-300 versions. I donated my effort to the Association. The prop called out on the STC is a Sensenich 74DC. (74DC-1-59) The STC names a Cessna spinner but I would guess the price is out of sight. I put in the wording "or FAA approved equivalent", so look for a bargain. Don't worry about it. The airplane will fly without a spinner! You could use your old spinner and backing plate if you know a machinist skilled enough to transfer the O-300D prop flange bolt and pin pattern to a new plate which must be riveted in to the old backing plate as a doubler. Since I got the STC, Sensenich gives me dealer price on new props. The price has gone up a little, but I believe I can sell one to you for around $1800 or $1900. I will have to check with Sensenich and see whats current. If you look for a used prop, get a 74DC-1-59 or 60. These were used on the Beech Musketeer with the TCM IO-346 engine. -- Jim

MONTY HAS MORE ON THE PROP DEAL...(MAY 04)
I have been asked to explain about prop reworking. First of all, major repairs and alterations to propellers must be done by an FAA repair station. An A&P mechanic may not perform major repairs to propellers, much less an aircraft owner. So what am I talking about by mentioning reworking a propeller? As an A&P mechanic I am allowed to do minor repairs, such as filing out dents, scratches, and corrosion pitting provided the strength, weight or performance of the blade is not materially affected. After I have done this the prop is sent to a prop shop where it is checked for conformity to manufacturers specs, overhauled and tagged. Specifically, I am talking about the McCauley 1A170DM series prop here. A little history lesson. From the early '50's to the early '60's the most common propeller in the whole aircraft world was the McCauley 1A170DM7653. This prop was furnished on most of the thousands of Cessna 170 and 172 airplanes with the C-145-2, C-145-2-H and O-300A and O-300B engines. When damaged, the 76" diameter prop could be cut down to a 73" diameter by cutting 1 1/2" from each tip. Those props were useless for anything but a Swift at 73" so they were not worth much. I used to buy them for $125.00 overhauled! Those days are gone! Those props are now getting scarce and just an overhaul now runs about $500. When I talked about reworking one, it was a $125, otherwise junk, damaged blade. If the shop later on scrapped the blade it was not much lost. Today, I would want the shop to cut the blade down to avoid exceeding the manufacturers minimums. Verbal instructions can be given to the overhauler regarding diameter and other blade rework. For a 145 Swift I recommend a 73" diameter and a blade chord near the manufacturers minimum and round tips.

THREE BLADE PROP...(MAY 04)
Subject: Re: Re;Props
From: Ebenguiat1@aol.com
Hello..........Has there ever been a Swift approval for three blade prop ? Ed

Ed
There are several, not STCs but various approvals. Don Bartholomew in NV has approval for one. <diamondswift@earthlink.net> Swift N78188 has a 3 blade installed as well as N3880K. -- Jim

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