7AC Prop
7AC Prop
I read all the discussion regarding props, especially recent dicussion from Nathan. I plan to buy a McCauley 1B90CM74/43 for my 65hp. Only question is whether I should buy a 74/41 or the 74/43. I am a little confused here. I orginally thought the 43 was a climb prop, but it may be standard. Confused on this and would appreciate any comments to clear this up. Also comments regarding performance. I am on a 2000' grass strip. Any used props for sale? Thanks.
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Jerry Eichenberger
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The smaller the second number is on the prop's designation, the finer the pitch of the prop. The first number is simply the diameter in inches. The second number refers to the theoretical distance in cruise that the prop "screws" thru the air with each revolution.
A 41 inch pitch is a climb prop. If I were dealing with a 2,000 foot strip (presumably sod with its inherent drag) in the summer heat in Texas, and if I wanted to carry any passenger, I'd go for the climb prop on a 65 hp Champ or Chief.
A 41 inch pitch is a climb prop. If I were dealing with a 2,000 foot strip (presumably sod with its inherent drag) in the summer heat in Texas, and if I wanted to carry any passenger, I'd go for the climb prop on a 65 hp Champ or Chief.
Jerry A. Eichenberger
Columbus, Ohio
614-798-1600
Columbus, Ohio
614-798-1600
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Guest
McCauley props
Jerry,
Thanks for the reply. Yes, it is a grass strip and I want to use a climb prop. I thought I would be getting a McCauley climb prop by ordering a 74/43, but that may be their "standard prop". I have not seen any reference to a McCauley 74/41. Not in any inventory from a prop shop, ads, or in any of our discussion forums. I have read in some of our discussions that the 74/43 was a good performing prop on their 65hp, but there was no reference to it being a climb or standard prop. I am a skeptic and I am afraid that a prop salesman may tell me that a McCauley 74/43 is McCauley's climb prop and collect about $2600. So, I am trying to verify from someone else's experience "What is McCauley's climb prop designation"? Is it a 74/41?
I guess I am getting old, but McCauley props use to be listed in catelogs that indicated the number and the type of pitch. Somehow things have changed (certainly the price) and things are not listed as such and McCauly props are harder to order. Have to rely on a salesman and I just want to double chech things from the experience of our members. Thanks.
Thanks for the reply. Yes, it is a grass strip and I want to use a climb prop. I thought I would be getting a McCauley climb prop by ordering a 74/43, but that may be their "standard prop". I have not seen any reference to a McCauley 74/41. Not in any inventory from a prop shop, ads, or in any of our discussion forums. I have read in some of our discussions that the 74/43 was a good performing prop on their 65hp, but there was no reference to it being a climb or standard prop. I am a skeptic and I am afraid that a prop salesman may tell me that a McCauley 74/43 is McCauley's climb prop and collect about $2600. So, I am trying to verify from someone else's experience "What is McCauley's climb prop designation"? Is it a 74/41?
I guess I am getting old, but McCauley props use to be listed in catelogs that indicated the number and the type of pitch. Somehow things have changed (certainly the price) and things are not listed as such and McCauly props are harder to order. Have to rely on a salesman and I just want to double chech things from the experience of our members. Thanks.
Foe what it's worth, all three of the Champs on our field have 74/43 props and they seem to work fine. Will usually rev up to around 2100 or so on takeoff roll and cruise around 80-85 mph at 2150 rpm. Weight makes a lot of difference with the 65's but they'll run forever on 4 1/2 gph.
Of course, we're in cool Wisconsin and not Texas, but I've flown on 90 degree days. Mosty just watch the wieght so as not to overload it.
We're on a 2300 foot grass strip with trees on one end and powerlines on the other
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Of course, we're in cool Wisconsin and not Texas, but I've flown on 90 degree days. Mosty just watch the wieght so as not to overload it.
We're on a 2300 foot grass strip with trees on one end and powerlines on the other
."If God had intended man to fly He would have given us more money"
ike,
Thanks for sharing your experience. I am currently using a wood prop 72CK42. That is a lot less to turn than the 74/43. I have good performance now. About 75-80 cruse, but the climb part is most important because of the high heat in the summer. The engine is fresh and good compression.
I have read that the metal prop will outperform the wood. I prefer metal for less maintainance and that it may windmill if the engine stops. Have a better chance of a restart.
Thanks for sharing your experience. I am currently using a wood prop 72CK42. That is a lot less to turn than the 74/43. I have good performance now. About 75-80 cruse, but the climb part is most important because of the high heat in the summer. The engine is fresh and good compression.
I have read that the metal prop will outperform the wood. I prefer metal for less maintainance and that it may windmill if the engine stops. Have a better chance of a restart.
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Nathan K. Hammond
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Here are the most common McCauley's for the A65:
74/38 - Considered the optimum seaplane prop
74/41 - Climb Prop
74/44 - Standard, or "combination" prop
74/46 - Cruise Prop
Personally, I would run anything between 41 and 44 inches on a A65. Generally you will always want more climb performace than cruise, so if you can't find a 44, look for a 43 If your looking for a 41 and can't find one, go with a 40. Just my opinion.
nkh
74/38 - Considered the optimum seaplane prop
74/41 - Climb Prop
74/44 - Standard, or "combination" prop
74/46 - Cruise Prop
Personally, I would run anything between 41 and 44 inches on a A65. Generally you will always want more climb performace than cruise, so if you can't find a 44, look for a 43 If your looking for a 41 and can't find one, go with a 40. Just my opinion.
nkh
7AC-5691
Super 85-12F @ DVK
Super 85-12F @ DVK
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Nathan K. Hammond
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Where are you getting that quote? I bought a 71/46 McCauley about 4 months ago, and it cost me around $2200-2300 (have to look in the morning) with out shipping. It was also drop shipped from the factory (which is owned by Cessna FYI). Most prop shops won't keep a new one on the shell, they simply drop ship from the factory because it's cheaper. It's very possible that the price has jumped at the beginning of the year. Anyway, my point is to call around to every prop shop you can find a number for. The price veried from what I paid, to $2500, and in one case $2600. So shop around, and you may find a better deal.
FYI: I think I got mine from Aircraft Specialist?? of Ohio I think, I'll look in the morning.
Secondly, lets say you want a 43 but all they have is a 45, haggle with them, and see if they will repitch it for free. Otherwise it will cost about $50 or so.
nkh
FYI: I think I got mine from Aircraft Specialist?? of Ohio I think, I'll look in the morning.
Secondly, lets say you want a 43 but all they have is a 45, haggle with them, and see if they will repitch it for free. Otherwise it will cost about $50 or so.
nkh
7AC-5691
Super 85-12F @ DVK
Super 85-12F @ DVK
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mike newall
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The metal 74/43 is a great prop for the 65hp Champ and would give the best alround solution to your problem.
I operated a very tired 65hp Champ with that prop out of 1200 of grass winter and summer, full up and at times probably more - never gave a hint of concern.
Cruise was 85mph indicated at 2100 r.p.m checked on a GPS
If you are on a Sensennich wood prop you will be amazed at the difference the McCauley will make. Yes it is heavier - that means the engine runs sweeter due to a better flywheel effect, it is far more efficient than the Sensennich - worst prop I ever ran on a Champ by the way - you will not regret the purchase.
I operated a very tired 65hp Champ with that prop out of 1200 of grass winter and summer, full up and at times probably more - never gave a hint of concern.
Cruise was 85mph indicated at 2100 r.p.m checked on a GPS
If you are on a Sensennich wood prop you will be amazed at the difference the McCauley will make. Yes it is heavier - that means the engine runs sweeter due to a better flywheel effect, it is far more efficient than the Sensennich - worst prop I ever ran on a Champ by the way - you will not regret the purchase.
Mike, thanks, I have heard too many good things about the 74/43. That is what I will get.
Nathan, I read your experiences with the new prop a few mos back. Hope all worked out with the extra holes, etc. I got my quote from PropWorksInc. I got two other quotes and they were in the $2600 range. I will call Aircraft Specialty and compare.
Thanks again.
Nathan, I read your experiences with the new prop a few mos back. Hope all worked out with the extra holes, etc. I got my quote from PropWorksInc. I got two other quotes and they were in the $2600 range. I will call Aircraft Specialty and compare.
Thanks again.
Guys:
I'm amazed that the 65hp can swing the same prop as my C-90. I have a 74-inch Sensenich on the front of my 7EC. It was repitched yesterday from a 44 to a 42 to get a few more rpm out of the engine. I haven't installed it yet, so I can't tell you how it turns after the change.
I delivered it to Maxwell, in the Minneapolis area (a two-hour drive) and their guy did the work while I watched and waited (and asked questions). The paperwork took longer than the repitch. He checked the track and balance as well. The whole thing cost exactly $100, so if you buy a new prop and it isn't quite right, you won't break the bank getting it corrected.
Jon B.
I'm amazed that the 65hp can swing the same prop as my C-90. I have a 74-inch Sensenich on the front of my 7EC. It was repitched yesterday from a 44 to a 42 to get a few more rpm out of the engine. I haven't installed it yet, so I can't tell you how it turns after the change.
I delivered it to Maxwell, in the Minneapolis area (a two-hour drive) and their guy did the work while I watched and waited (and asked questions). The paperwork took longer than the repitch. He checked the track and balance as well. The whole thing cost exactly $100, so if you buy a new prop and it isn't quite right, you won't break the bank getting it corrected.
Jon B.
Jon B.
Much like Jon, I'm amazed - or confused. I'm turning a 74/42 on my 115HP Champ and not making anywhere near redline in S&L flight. I tried a 74/44 and it was downright doggy without adding anything to cruise. My T-cart has a 74/40 on a C-90 and it seems about perfect to me. Someone care to explain this mess?
props
you might want to check out the "product guide" for wood/metal props at http://www.sensenich.com . lists various pitch and diameters for aeroncas in metal or wood. looks like the pitch stays close but the metal props are longer.
ps
the aeronca service letter #17 for converting a 11ac to a 11bc( a-65 to c-85) lists sensenich props as 72gk46/72gk48 and mccauley as cf7144/cf7146. further states the prop must meet the the diameter and stataic rpm limits listed in the type certificate 11ac is #a-761 and the 7ac is #a-759. hope some of this helps.