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I could be wrong, but I'm pretty certain this won't work on a pusher. I believe it uses a pre-loaded vane system on the nose to detect airspeed and set pitch accordingly.

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The application list are all certified types and at least one of them, the Piaggio P 136, is a pusher.

 

Posted Image

 

I have seen such props that have the vanes on the nose, and expect they wouldn't work, but this is something different, check out the FAQ. If this isn't snake oil it would be brilliant on a canard. Cost is reasonable. I'm excited!

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...On the other hand, noted in the 'News' tab:

ALERT - ALERT - ALERT

 

AEROMATIC MODEL F200 ON 0-320 AND 0-360 LYCOMING ENGINES

 

BACKGROUND: I spoke with Univair, previous owner of the Aeromatic propeller, concerning the use of the F200 on the above named engines. In 1963 Univair pursued the certification of the F200 on a Beech 23 equipped with an 0-320-D2B. This is a 160hp engine. The tests that Univair conducted proved that this particular engine/propeller/airframe combination is not compatible.

:sad:

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The F220 is rated for engines up to 260hp...

...and fits on a splined shaft, not a flange.

 

I note the owner is planning to fit an F200 on his 0-360 Bellanca, so he doesn't read his own alerts...:confused:

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Well well, I find these comments interesting.

 

First: Univair did over 50 hours of flight test on the Musketeer with the 160 hp engine.  They got FAA approval for the combination.  I have all the test reports, the TIA and the letter of approval.  There is no mention of the prop not being compatible with the 0-320.  And they did whirl test on the 0-360 180hp and that was also approved.  I asked Steve, owner of Univair, why they did not go ahead with the approvals for those engines.  I never got a satisfactory answer but since this was going on during the big low in airplane sales and high in law suits during the 80, I can only assume that they were spooked like a lot of other people during those law suit days. 

 

I don't get the point, "..... so he doesn't read his own alerts".  What alerts?  Who's alerts.  Stone throwing is so cheap.  That is what is going on in the cosmology and religious arenas all over the web.  And it is getting into the medical arena too, and that may not be all bad.

 

We make a special prop for a local Veri EZ, it is performing better than expected, cuts his takeoff by a large margin, he says it cuts him takeoff in half.  My son is flying it, Veri-EZ with C-90.  The propeller is smooth as silk on the EZ.

 

Yes it gives much the same performance that a CS prop would, don't need a governor, hollow crankshaft and weighs about half that of a metal CS prop and it doesn't dome apart on the back of an EZ like metal props do.  The prop, in fully automatic version, looses about 20 rpm per thousand feet of altitude.  If you use high altitude airports you can make a small change in counterweights to gain back the rpm at higher altitudes.  So you can make you adjustments to suit the conditions.  I have designed a version for pilot control and I also have designed a CS version.  Neither of which need governor or hollow crank.  I was targeting the certified market for them but the Federal Anti Aviation Administration doesn't like me or the damn prop.  Theat is typical of someone who doesn't understand something, they want to get rid of it.

 

Anyhow, I am changing my target customers from certified planes to EAB airplanes. 

 

BTW.  In case you are interested, in the 70 years the prop has been available for the certified market there have been only three AD note against it.

One is the tipping.  The leading edge metal has relief cuts about every 5".  These relief cuts did not go around the leading edge.  The outer 5 inches would come off sometimes because of the tip flexing near Mach one.  So the AD note cut the relief cut to go all around the leading edge from bottom to the top.

 

Another AD put a rpm restriction on the 165hp Stinson 108.  There was a vibration above 2650rpm.  The AD not only applied to the Stinson and not the Bellanca that used the same engine.  So after the AD came out further research was done on the Stinson.  They found that there was a small design flaw in the hub.  There was an interference a high pitch angles.  So they wrote AD note.  After the AD came out they found and fixed the interference problem by making a mod to one of the parts.  This fixed the problem but it didn't fix the AD note problem.  I presented the whole story to LA ACO and asked them to remove the AD note.  I got some crap that AD notes live forever, you can't kill them.  Our FAAA at work on our nickel.

 

The other AD note requires the removal, to one side, of the balance band around the barrel and inspect for cracks.  There was one crack found in a prop back in the 40s or 50.  They wrote an AD note.  Turns our that the snap-ring-groove that receives the snap ring that holds the blade in the hub, had a faulty machining in it.  So they wrote an AD note.  But when they found out the problem they never went back to kill the eternal AD note.  There has never been another hub found with the faulty machining.  I tried to get LA ACO to remove that one too but when the FAA hears something they don't like they clam up and become verbally constipated.  And if thye got you on their Cada LIsto, the whole office goes into hibernation, instead for the cold season, it last for years and years.  Oh, and so does our FSDO and MIDO.

 

Another little note of interest, maybe.  I made two props for the EZ.  The first one I used an existing blade design that came with the engineering that Koppers did during WW-II and later for civil aircraft.  Those airplane were in the 60 to 130 mph speed range.  The fastest plane they designed for was the Bellanca and maybe the Johnson Rocket. 

 

There is something that I am not even sure the big boys know about.  That has to do with not only the pitch but also the amount of twist in the blade.  When you start getting up toward the 200 mph, actually in the 150 mph rang, you have to, for best efficiency, design more twist in each blade.  I don't plan to go into the math and talk about Archimedes Screw here but it is important.   

 

And here is another little tid-bit of data.  You may have heard that Hartzell came out a few years ago bragging about their new "Blended Airfoil" propellers.  Well well, every propeller blade, at least in the last 75 or more years, has a blended airfoil.  If it didn't the efficiency would be so poor that you could outrun your airplane on foot.

 

 

 

Another

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...On the other hand, noted in the 'News' tab: :sad:

I am getting close to putting my Mustang II in the air.  Will be using an Aeromatic prop. It will be set as a fixed pitch prop for first flights.  It will have the 0-320.  After flight test with that engine prop combination I plan to put an 0-360 and I will be designing new blades for the prop because that is a 200 mph airplane.  I want to get some engineering and performance data so I can tell anyone what kind of performance increase I get.

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The Aeromatic model 220 fits the 20 spline shaft engines.  It was certified on the Navion 260.  SAE No. 2, spline.

The Aeromatic moded F200 fits the flange shaft.  There are 8 different bolt patterns for the flange shaft props.  The smallest fit the Franklin 90hp, six bolts about 4" dia,  there are two 8 bolt patterns, one 4.75" dia. and one 5" dia.  I don't remember all of them right now.  I'm not in my office.

 

The Aeromatic does not work on the same principal as the props that have vanes on the spinner to control pitch.  The Aeromatic used aerodynamic forces on the blades, centrifugal forces on the blades and counterweight to create a balance of forces that changes based on RPM, AOA & airspeed.  The Aeromatic works very well on a pusher. This makes the Aeromatic almost constant speed. 

 

When you are sliding down the final approach the blades will be in whatever pitch you had before you throttle back for the descent.  If you decide to abort the landing, you push throttle full on, the rpm goes up to redline and the prop pitch shifts back into full rpm and climb power is realized. 

 

There is a version of both props, the F200 and the 220, where the pilot can take over pitch control if he needs to.  The flange shaft F200 needs a hollow shaft engine with a governor pad.  The 220 uses mechanical means of controlling the pitch, all outside the engine.

 

During WW-II the prop was used on the Fairchild PT-19, Stearman PT-18 prototype, Grummon Widgeon, the UC-78 Cessna Bamboo Bomber.  But it came late in the war and there was not a lot of military planes using it. 

 

I have a story in the archives that the Widgeon with the 200 hp Rangers originally had fixed pitch props.  They were used for submarine patrol up and down the east coast.  Story says that if they lost one engine they would throw everything they could get loose, overboard just so they could bet back to base on one engine.  With the Aeromatics they could complete the mission on one engine.

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Kent,

You are responding to a post from 7 or 8 years ago, right? If you get several different types of experimentals flying with this type if prop, get a couple thousand hours of proof flight time, and sell them for a great price (less than a Catto), you could sell a bunch of them.

 

Builders are interested in safety, performance, and low cost.

 

Andrew Anunson

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I can not compete with fixed pitch props, they are much easier to make.

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Well, for a variable pitch prop, you do have a good price.  Is there any way you can take a fast experimental (RV series or Rutan style pusher would be great), and do a controlled test putting your Aeromatic up against a Hertzler or a Catto that was specified for that same airplane?  Or, you could do a Aeromatic vs. "Brand X" variable pitch prop, compare the results, and compare the price.  If you can't compete pricewise with the most expensive fixed pitch props ($3.5k), then perhaps its time to do a controlled experiment and publish the results.  EAA might even publish a story about your prop in their magazine.

 

There is a huge market out there, especially in the RV arena, but until you have recent proof (not history from long ago), it will be difficult to sell any product.  

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I am posting this on behalf of Kent, who mistakenly replied to the forum notification email (which only I receive). The topic is interesting so I'm more than happy to help it along.

 

Actually it is not a constant speed prop. And that is not the problem. The problem is that the meal props. There are pushers with CS composite props. Even metal fixed pitch can’t take it. All because of the air coming from off the mass in front of the prop sets up a resonate mode for the metal blades. Vibration sets in and of course that is destructive. CS or Fixed, same problem if they are metal blades.

 

The Aeromatic is the “original” composite prop. Before the days of fiberglass they covered the prop with cellulose nitrate sheet. Same as nitrate dope, but in a solid form. Beech Roby props used it and they called it “armor coated”. You may know that Beechcraft sold to Roby prop stuff to Ole Flottorp. Ole then called them Flottorp Controllable pitch props. As you may know, they had a hand crank in the cockpit so the pilot could control pitch.

 

The blocks of wood are a layup of 1/16” veneer. First sheet strait grain (grain parallel with length. second sheet the grain is 15 degrees left, next sheet is 15 deg right then strait etc. This is much superior to the props made of planks like the Sensenich. To find a blade that has warped is a very rare thing.

 

Wood blades are naturally dampening’'. We have about 30 hours on the EZ. We have disassembled the prop twice and found no problems. It runs smooth.

 

The prop we made for the EZ is covered with carbon fiber. That adds stiffness and raises the resonate frequency. Virtually everything has a resonate frequency. For these wood composite blades their resonate frequency is outside the excitation frequency created by the engine.

 

BTW, is there an instruction sheet on how to use the forum? There are so many different system I can’t keep up with them. Seems like every forum has a different way of doing things.

 

Kent

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W

 

Actually it is not a constant speed prop.

The Aeromatic is the “original” composite prop.

Before the days of fiberglass

Beech Roby props used it and they called it “armor coated”.

To find a blade that has warped is a very rare thing.

I never said it was a constant speed prop.  

ALSO... while the history of the design is very interesting, it won't sell your props.  Will you be providing any testing data in the future?  

 

Have you considered marketing to the much larger experimental world of tractor design aircraft?

Edited by Andrew Anunson

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Was said: "30 hours on an EZ"

 

Here is the problem with testing props on an EZ:  The Rutan pushers are not good airplanes for testing things that might fail catastrophically.  

 

I have checked out a few guys and when I pulled the power to idle and said "Engine failure", they would generally have trashed their airplanes and/or killed themselves trying to dead-stick into some place.  These are not easy airplanes to dead-stick into anything: fast, shallow glide and no good drag devices to control the glideslope, fragile landing gear, heavy engine that wants to swap ends during a sudden stop.  Pilots generally fly too fast and overshoot what they're aiming for.  And we don't practice enough.  Yeah, you could wear a parachute but who wants to bail out of their baby?

 

I am a chicken.  If I saw several pushers flying these props with 800-1000 hours each on them I might try one.

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I am well aware of the problems of dead sticking pushers and especially the EZ type pushers.  We have been flying this bird off and on for the past two years.  We have made two props for it.

 

I have never been in love with the EZ  type airplanes for several reasons but I have to admit that their record does not shoot fear through my nerve system.  If an airplane has problems the news moves through space like plasma in the universe.

 

I gave a sorta of a plan of action for the future of the Aeromatic prop for the EAB market.  I have a Mustang II and plan to do much flight testing after I get a warm feeling about the airplane and the engine.

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We, in the general aviation community, have strong feelings about our airplanes and other's airplanes and things that are bolted on our airplanes.  Not only do facts play a part in our hobby but so does emotion.     The Aeromatic propeller probably has the best safety record in the business.  The CAA/FAA has no record of a failure of one of these props.  But many FAAA employees, like many in the aviation community, have strong emotional opinions about technical things of which they are not qualified to judge.  That makes the FAAA inspectors, those of little competence,  I reckon enough of that.

 

Back to the subject.  The Aeromatic is a wood blade prop.  They are covered with fiberglass.  The MT prop blades are made the same way, laminated wood core covered with glass.  Our EZ prop is covered with carbon fiber, this adds some stiffness to the blades. We are planning another trip with the EZ.  Weather permitting, we plan to fly it to PHX in a couple of weeks.  We have had it as far as Kanab, UT.  We plan to put many more hours on it.  So far, we see no problems.  It is a good performer and is smooth as silk. 

 

So, this prop is a wood prop.  It has the advantages of wood as well as variable pitch.  I have no intention of selling a prop that I am not comfortable with myself.  My son is doing all the flight testing.  I have some data that he collected last week.  I hesitate to put it up because the plane doesn't have a calibrated airspeed or tachometer. I am rigging up a way to use my electronic proptach to fix that problem and he will be calibrating the AS indicator using GPS, soon, I hope. And since the propeller responds to gusts, (the pitch changes in response to a slight AOA on the blades) the data is a little misleading and easy to be misunderstood.  The one thing that was confirmed was that the rpm drops at a rate of about 20rpm per each 1000' of altitude increase.  He flew from 5K to 12K and the rpm dropped almost exactly 20 rpm per thousand feet.  That pretty well confirms the engineering flight test data that I have on whole bunch of airplane of the late 1940s and into the 1950s.

 

My records indicate that between Koppers and Univair, there were over 9000 aeromatic props installed on about 50 different certified airplane, foreign and domestic. 

 

BTW, just for kicks.  We, that is America, gave Russia, during WW-II some L-5s.  Those Pekkerheads reverse engineered the prop and designed one with metal blades.  A friend of mine has one on his Nanching CJ-6.  I asked another owner of that combination, if it worked like the Aeromatic and he said, "It does indeed". 

 

Soon as we can get more reliable flight test data I will post it here.

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Here is some preliminary data on the Veri-EZ with the Aeromatic prop.
 

I have been trying to get my son to do an airspeed calibration with GPS.  So far very little.

But here is some GPS GS data flying a variety of headings in gusty conditions. The propeller changes pitch and rpm in response to gusts.  You will notice that the data is somewhat convoluted.  Neither the AS nor the Tach is calibrated. GS was off a GPS.  We are working on getting better instrumentation and looking for some smooth air so we can get some reliable data. You can see that IAS is low compared to GPS GS.  The rpm averaged about right, 20 rpm/1000'.  We don't have fixed pitch prop flight data.

 

BTW, this Veri-EZ almost 200# over Burt's EW with the old fixed pitch wood prop.  So the flight data is pretty much equivalent to GW flight. The prop weighs about 38#.  My son weighs only abut 150 so we have about 25# of ballast in the nose.

 

C-90 In Veri-EZ.

 

5K - rpm 2650 MP 24.25, Temp 34.9 F, GS 170mph, IAS 138Kts.

6K - rpm 2620 MP 23.50, Temp 30.6 F, GS 165mph, IAS 135Kts.

7K - rpm 2610 MP 22.50, Temp 35.5 F, GS 158mph, IAS 135Kts.

8K - rpm 2580 MP 21.75, Temp 36.2 F, GS 151mpn, IAS 132Kts

9K - rpm 2570 MP 20.75, Temp 35.0 F, GS 156mph, IAS 128Kts

10K-rpm 2570 MP 20.00, Temp 32.8 F, GS 155mph, IAS 122Kts

11K-rpm 2530 MP 19.00, Temp 31,5 F, GS 154mph, IAS 118Kts

9.0K rpm 2590 MP 21.82 Temp 33.7F GS 158.4 mph IAS 129.7 Averages

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That is a loss of about 20 rpm per 1000' of increase altitude. 

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I don't get the point, "..... so he doesn't read his own alerts".  What alerts?  Who's alerts.  Stone throwing is so cheap.  That is what is going on in the cosmology and religious arenas all over the web.  And it is getting into the medical arena too, and that may not be all bad.

 

...and hello to you too Kent. If you wish to hear the reason for my "medical issues" look at post #4, not just #6 before flaming at me. These posts were made on the same day in 2008, and #4 has a quote from the news section on www.aeromatic.com which I reproduce here, and no longer appears:

 

 

ALERT - ALERT - ALERT

 

AEROMATIC MODEL F200 ON 0-320 AND 0-360 LYCOMING ENGINES

 

BACKGROUND: I spoke with Univair, previous owner of the Aeromatic propeller, concerning the use of the F200 on the above named engines. In 1963 Univair pursued the certification of the F200 on a Beech 23 equipped with an 0-320-D2B. This is a 160hp engine. The tests that Univair conducted proved that this particular engine/propeller/airframe combination is not compatible.

 

This seemed to me incompatible with bolting one on a Bellanca, but now I read "engine/propeller/AIRFRAME" and see the two may not necessarily be at cross purposes.

 

Assuming you are Kent Tarver, I am still as interested in your props now as I was in 2008, and I have built a fair bit of aeroplane since then. Please keep us informed of your progress, as if it is suitable for a pusher with a 160-200hp engine and the speed range we experience it is a marvellous product. As it is the only information I can actually find is my own posts from 2008, your website and images such as this. And they don't explain what happened.

 

P1000421.JPG

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I have no idea what this is.  Does anyone know what airplane and engine? 

 

I think I send up the story about the guy that had his Aeromatic dynamically balance (Unbalance) on his Aeronca.  It ended up breaking 5 of the 15 screws that hold the blade in the hub.

 

You got to pay attention to clocking the  prop on the crankshaft.  There was an excellent article about that subject in the Coupe Capers. 

 

I will ask the people at Coupe Capers for permission to make the article available here or make it available via e-mail.

 

BTW I am working on a design for a controllable pitch prop that should be almost as light at a fixed pitch wood prop.  It will be carbon fiber of course, the blades anyway.

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It's getting confusing.  In my early days with the Aeromatic prop I was getting up on the learning curve.  I was relaying some of what Univair said about the propeller.  OK, so all of the said and done aside lets look at the record.

 

FAA approved the prop on the 0-320 on the Beech 23, and on the Supercub and for use on the 0-360.  The only blade that has slung off an Aeromatic is the one I personally was given the opportunity to investigate.  Maybe I am repeating myself but this comes from two friends of mine.  One guy had an Aeromatic for many years in his hangar, I saw it several times, it look to be in excellent condition.  I told him to let me to the SB on it to check for any problems. 

He didn't do that.  He sold the prop to another friend of mine that had a 0-320 powered RV-4.  They put it on his airplane, he took off and flew around the pattern.  (At private airstrip, Faris Wheel near Minden, NV. 

 

First flight they only got 2100 rpm.  Landed tweeked the counterweights and flew again,.  Slung a blade but made safe dead stick on the runway.  Never found the blade.  Gave me the hub with other blade to analyze the failure. 

 

Turn out that of the 15 screws that hold the blade in the metal ferule had 10 broken screws.  They breaks were rusy.  So they did not break during this flight.  Of the other five screws, two had fresh breaks and the last three pulled out of the wood. 

 

So, it is clear that the prop blade exerts more centrifugal force that 5 screws can handle.

 

I have inspected quite a few props that come to me for inspection/overhaul.  I have found up to five broken screws in some of them, usually only three are found broken.  No history of any of these blades departing the hub.  Univair told me that they certified props out the door with as many as three broken screws within.  It is sometimes impossible to get the broken screw out of the blade if the break is down in the wood.  If the head breaks off we can usually get the screw out.  I have chosen not to certify a blade with any broken screws.  Also my screws are made fro 8740 steel which is about 10 to 20% stronger than the original 3035 steel used by Koppers and Univair.  Thie original screws were Rockwelled to about 160K to 180K PSI hardness.  My 8740 screws are Rockwelled to 180 to 200K Psi with the same spring characteristics.  None of my new screws have been found broken except where there was a prop strike.

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Thanks for the info Kent. I wonder if this is that RV4???

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Has anyone seen anything new from Aeromatic?

I have called and left voice mail twice and sent an email through the website and no response?

I have Cosy Classic(not a typo Cosy) with a 4 blade MT constant speed prop and i am tire of paying for repairs to the blades from FOD... about 2000 dollars per blade!

I was considering this type of prop but i cant get anymore data on how the testing Kent was doing on the Long EZ!

Kent... you still on here?

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