plastic props? adjustable props?

Jon Stark · Post by **Jon Stark** » Sat Mar 22, 2003 3:18 pm

Are there any composite or adjustable props in use on the O-300 that might make the performance of the a/c better off a high/hot field but still provide a good cruise?

Willing to go experimental but prefer to avoid the hassle of getting back off exp when done or selling.

thx, jon

Post by **GAHorn** » Sat Mar 22, 2003 5:00 pm

The old Flottorp (Aeromatic) props were originally approved, but they're obsolete now. I've also sometimes wished for a ground adjustable metal prop, or better yet, a Beech type electrically adjustable prop.

lowNslow · Post by **lowNslow** » Sat Mar 22, 2003 7:05 pm

gahorn wrote:The old Flottorp (Aeromatic) props were originally approved, but they're obsolete now. I've also sometimes wished for a ground adjustable metal prop, or better yet, a Beech type electrically adjustable prop.

It's really to bad they don't reintroduce a modern version of the Aeromatic, it seems there a lot of aircraft other than the 170 that could use one. It gives most of the benefit of a constant speed prop without the complexity, cost and weight.

zero.one.victor · Post by **zero.one.victor** » Sun Mar 23, 2003 5:27 am

I seem to recall that while back Tom Downey posted a website address for an outfit that claims they will be producing the Aeromatic prop again. I guess they have the TC for it. Sounds like another pipe dream. Probably the best we can hope for is that they will be able to support the old Aeromatic's still turning out there.

Eric

Jon Stark · Post by **Jon Stark** » Sun Mar 23, 2003 4:14 pm

I'll be in touch with Kent Tarver this coming week on the Areomatic prop. He has the production rights for the Aeromatic. The FAA has not yet given him his PMA but there is movement in that direction as I understand it. I'll post info on our conversation.

I am also interested in the composite props that the RV guys are using. I'll go over there and ask them and post our high points here too.

There doesn't seem to be too much interest in this subject... Are guys either happy enough with the climb/cruise performance of their metal props or is this an area that could use some experimentation?

thx, jon

zero.one.victor · Post by **zero.one.victor** » Sun Mar 23, 2003 4:48 pm

I think all of us would be happy if we could increase the performance of our 170's. But I think most of us are realistic enough to believe that unless we do something drastic like an engine upgrade,we'e not likely to see big improvements. Tweaking the propeller pitch,losing some weight (both airplane & occupants!),and aerodynamic clean-up can all result in some noticable ( but not earth-shaking) performance gains.
I'd like to see the Aeromatic prop produced again,especially if they could make the blades out of composite material. I believe the original wood blades are at least part of the reason for an AD and for some catastrophic prop failures--the wood rots out where it attaches to the hub with a wood screw,and the blade parts company with the hub. Not a good thing!
But if they do start Aeromatic production again,what do you think the price is gonna be? A regular Maccauley fixed pitch lists for well over $2K new,as does a Sensenich.
Adjustable/variable/controllable props for experimentals are affordable cuz they don't have to meet any certification requirements. Anything we'll be able to bolt on our 170's is gonna be big money.
But it's nice to dream.....

Eric

zero.one.victor · Post by **zero.one.victor** » Sun Mar 23, 2003 4:50 pm

Jon Stark wrote:Are there any composite or adjustable props in use on the O-300 that might make the performance of the a/c better off a high/hot field but still provide a good cruise?

Willing to go experimental but prefer to avoid the hassle of getting back off exp when done or selling.

thx, jon

Please elaborate on how you would "go experimental". Thanks.

Eric

Jon Stark · Post by **Jon Stark** » Sun Mar 23, 2003 6:12 pm

The first thing that I would do is what I always do before cuttting metal or spending money. I'd talk to my PMI down at the FSDO to discuss my plans. If we can agree on a plan to "go experimental" to investigate an installation then I might proceed.

The a/c must be conformed prior to going to get a baseline to facilitate gettting off exp later. If I thought that I might have a project worth proposing to a manufacturer of certified props (that being a marketable STC) then I might ask them for help providing a prop.

Alternatively, I could go experimental for the period f time that I felt like playing around with props on my own. (How much money do I have...) My problem being that I fly out of an urban airport and would probably be prohibited from flying out over the locals in either event.

A guy can always dream can't he and it don't hurt to see if this has all been hashed out before by folks more knowledgeable and experienced than myself.

jon

pauldpilot · Post by **pauldpilot** » Sun Mar 23, 2003 7:30 pm

I see that it is possible to take the aircraft into the Primary category by STC process. Once it is in Primary, the owner does the maintenance. But does the aircraft still have to have an annual insprction? If not, it would seem a way to "play around" with different ideas, much the same as an Experimental.
Reference FAR 91.325, 21.24, 21.184(c).
Food for thought.

Sun Mar 23, 2003 11:56 pm

I for one would be very interested in a prop like the Aeromatic.

As for the cost of such a prop you would have to compare it against any other performance improvement you could make like an engine upgrade.

I've heard the 180 conversions will cost over $30G. If I could buy a prop for $10Gs that allows me to use all 145hp at takeoff instead of the 115 or 120hp I get now and increase my cruise performance as well, it wouldn't be a hard decision. Of course if the prop where only $5Gs it would be a lot easiar to find the money to do.

A friend of mine already has 2 Aeromatic hubs. Just needs blades. Only problem is his hubs are the 6 bolt pattern

Another friend is currently flying aerobatics with an Aeromatic prop on a Ranger engine in his Great Lakes and has had no trouble and likes the prop.

I'm also waiting for someone to develop an electrically controlled "plastic" prop for the masses of regular planes like the 172 and Cherokee 140 that could be adapted to our planes with a simple 8 bolt pattern. I talked to a fellow developing a prop for the high end Lancair IV and Glasairs and he though one cold be brought to market in the $5G to $6G range.

Jon Stark · Post by **Jon Stark** » Mon Mar 24, 2003 12:15 am

I got a note from Kent Tarver in Nevada who is trying to get the OK to produce the Aeromatic. He says that he is shooting for $4000 for a new production Aeromatic. He hopes to be allowed to make them in about a year.

I also got a note from the SoCal rep for MT props, Jim Ayers. He is going to look into a possible prop for this application and will let me know in the next few days.

Once you're experimental you don't have to do any of the manufacturers recommended maintenance. The rub is that the entire a/c must be conformed and all the mx brought back to zero when coming off exp. The hot tip is to keep up the mx all the while. You would then be able to appeal the need to zerotime the mx when coming off.

Wish I had my copy of the FARs at home. I keep wanting to refer to them during these posts. Gotta go get another set...

jon

russ murri · Post by **russ murri** » Tue Mar 25, 2003 4:26 am

how well do the composites do in the dirt and gravel strips as for nicks from rocks and the likes?

zero.one.victor · Post by **zero.one.victor** » Tue Mar 25, 2003 5:38 pm

Jon Stark wrote:I got a note from Kent Tarver in Nevada who is trying to get the OK to produce the Aeromatic. He says that he is shooting for $4000 for a new production Aeromatic. He hopes to be allowed to make them in about a year................................................................................................................................
Once you're experimental you don't have to do any of the manufacturers recommended maintenance................................

jon

Jon,first of all,I was wondering if you could post Tarver's Aeromatic website address. IF he can produce them and sell them for around $4K, I'd be interested. I'm curious if they plan for wood blades or for something a little more Y2K-ish.
Secondly,even if a person was to "go experimental",I would think that he'd still want to do the manufacturer's recommended maintenance on his airplane and any components thereof--I'm sure there's a reason why that maintenance was recommended. After all,our lives are riding on the actual (not paperwork) airworthiness of our airplanes.
I gripe about the annual inspection like averybody else,and the pilot BFR,but in reality I have to say that they're both probably a good thing.
Maybe the bi-annual inspection rule that was proposed a few years ago would be sufficient.

Eric

lowNslow · Post by **lowNslow** » Tue Mar 25, 2003 7:45 pm

$4000.00 seems about right. A new Hartzell constant speed prop runs about $8000.

Jon Stark · Post by **Jon Stark** » Wed Mar 26, 2003 12:18 am

go to Aeromatic.com

The International Cessna 170 Association

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