Exact Model of Neuform Prop?

[Tom Baker]

2 hours ago, FlyingMonkey said:

The factory says to pitch for 5500rpm WOT in level flight.  Not sure about that advice...I like to bias toward climb instead of cruise, and it seems to me pitching for a little higher rpm at the 2000-3000ft altitudes I usually fly at might give me a little more climb and some rpm headroom for when I climb higher on longer flights.  But the way this prop works, I'm not sure if my "normal" prop thinking will work out.

I think that if you try to set the pitch for more than 5500 level flight, that you might have to be careful when putting the throttle in for take off. Like I said above it doesn't act like other props I've flown behind.

[Tom Baker]

10 minutes ago, Roger Lee said:

Andy,

You won’t know until you try it. Nothing ventured nothing gained. It’s an easy adjustment. I’ve proved several companies wrong. Go for it and report back.

It is not as easy to adjust as as the Nueform or Sensenich. Having just installed and flown one it performs different than other propellers. A couple things I noticed is that it seemed smoother, and the shut down was much softer. Another big plus is that it is quite a bit lighter.

[Madhatter]

I don't know how everyone else sets their prop angles but cheap digital protractors have poor repeatability. I found that setting one blade with a digital protractor is fine. After that I use a precision machinists bubble protractor after adjusting it to that blade and using it to set the others to match and then re verify. Bubbles don't lie. 

[Anticept]

With neuform props: half a degree translates to around 100 RPM static when you're close to the correct setting. It is THAT sensitive. That's why you need the longitudinal measurement and lateral leveling before and after every prop blade setting, it's that much of a precision operation!

I use angle finders. Take out top plugs, pick a flat spot that exists near all the blades. You're measuring the level of the LONGITUDINAL axis of the airplane first, because that will affect blade angle measurements!

Let's make sure all the spots themselves are flat respective to one another. Measure, turn prop, measure the new spot, turn prop, measure, and again rotate and measure until you are confident they are all equal. Make sure you get the same reading, in the same spot relative to each individual blade. Don't zero it, just measure, some angle finders like to "snap" to zero, avoid them if you can, but really I just don't use the zero function. If the spot they match after a few rotations, the place you chose is a good reference for setting the blades.

Set the angle finder on the top of the blade in a flat spot (i'll put it next to the hub), and this time you are going to find the level point LATERALLY this time. When it's reading zero, measure out a distance from the hub as appropriate to the instructions, and you are going to set the angle based on the DIFFERENCE between the longitudinal axis of the airplane, and the blade angle. If the airplane is sitting down a hill, this will obviously change what you measure on the blade angle, that's why you use the DIFFERENCE.

Every time you change the blade angle, or rotate the prop to set the next blade, you're starting again with the hub. If the hub measurement changes, don't worry, I repeat, we are concerned about the DIFFERENCE between the hub and the blade angles. Sometimes just turning the blade can cause the airplane to settle a little and move it a fraction of a degree.

I have found that neuforms are really close when they are set relative to the hub at 30.5 degrees at 1000 MSL. I'll see around 5050 RPM static full throttle on a hot day (90F), almost 5600 WOT at 3k feet. If that's too pitchy, adjust by 0.5 degrees for each 100rpm (roughly) adjustment that you need.

[Tom Baker]

I have a homemade prop pitch fixture. It uses a bubble level to get the blades in the same position every time, and a 6" Craftsman digital level for the blade angle. It works well for me.

[FlyingMonkey]

7 hours ago, Madhatter said:

I don't know how everyone else sets their prop angles but cheap digital protractors have poor repeatability. I found that setting one blade with a digital protractor is fine. After that I use a precision machinists bubble protractor after adjusting it to that blade and using it to set the others to match and then re verify. Bubbles don't lie. 

I was going to use my Warpdrive protractor, it has a bubble.

[ls6pilot]

ELSA prop change
Just when I thought I was confused enough about what defines a major alteration, and what to do if one is made, I found the following paragraph in an advisory circular.

(This subject of this advisory circular is certification of light sport repairmen. It includes the statement in bold below:)
 

Major Alterations. If the aircraft is issued an ELSA certificate, a non-certificated person may perform additional maintenance, preventive maintenance, or alterations on the aircraft. If a non-certificated person performs a major alteration, as defined by § 1.1
(e.g., changing the engine to another model that increases the original engine horsepower by
10 percent or more), he or she must make a maintenance record entry and a new FAA
Form 8130-6, Application for U.S. Airworthiness Certificate, and send it to the FAA Aircraft Registration Branch (AFS-750). A new FAA Form 8130-6 is required because he or she has modified the aircraft and it is no longer the same aircraft as identified on the original FAA
Form 8130-6 in the aircraft’s file. A Designated Airworthiness Representative (DAR) or FAA aviation safety inspector (ASI) will review the change(s) and issue new operating limitations for the aircraft. The issued operating limitations may require the aircraft to be put in a flight test area for a certain number of hours until the owner/operator has flight tested the new alteration and the aircraft is proven to be safe to operate within its design envelope. When the flight-testing is complete, the test pilot should sign the aircraft off as safe-to-fly in accordance with its operating limitations. (See Appendix 1, Figure 2, Sample of a Major Alteration Entry for an Experimental Light-Sport Aircraft (ELSA)).

 

My opinion is that if one considers the prop change to be a major repair, one should notify the FSDO and the FSDO may require some flight testing. 

This circular’s statement that one has to fill out a new 8130-6 blows my mind.

Appreciate your thoughts.

ac 65-32a.pdf

[Madhatter]

Again the EProp is not experimental. It is manufactured and certified and tested under ASTM requirements for the CT which is also manufactured under the same requirements. It's no different than removing a Hartzel prop and installing a McCauley prop designed for the particular aircraft and engine. The only difference is that the SLSA manufacturer gets to decide what they want to approve. Maybe FD has a financial deal with Neuform,  who knows. The other prop manufacturers should be very worried, as the Eprop is lightyears ahead of them. When you fly with one you will understand. 

[Anticept]

I'm confused, what does the props' certificates have to do with alterations? I don't think I've seen anywhere in here with someone calling the *prop* experimental.

[Madhatter]

Having to fly hrs in a test area is for unproven props not for certified props for the particular aircraft and/or engine. A major alteration is for an unproven prop for that aircraft which would have to be categorized as an experiment. I have a J3 cub with a certified sensenich wood prop. I also have a certified McCauley metal prop certified for the aircraft that I can install with a log entry and a new weight and balance computation. 

[FlyingMonkey]

21 minutes ago, Madhatter said:

Having to fly hrs in a test area is for unproven props not for certified props for the particular aircraft and/or engine. A major alteration is for an unproven prop for that aircraft which would have to be categorized as an experiment. I have a J3 cub with a certified sensenich wood prop. I also have a certified McCauley metal prop certified for the aircraft that I can install with a log entry and a new weight and balance computation. 
 

Untrue.  Flying off test hours is standard for ALL experimental aircraft that undergo a major change, whether E-AB or ELSA.  A major change is anything that could substantially affect performance or flight characteristics of the airplane.

A prop is a major change.  If you think you can just swap to any prop you want as long as it's a "certified" prop or one approved by the manufacturer on an ELSA, without telling the FSDO or any flight testing, you are wrong.

[Madhatter]

I've been changing props and other things on all kinds of aircraft for 47 yrs experimental and certified so I guess I should have consulted with you.  I suppose it would have been easier not to take my IA exam ( the hard one with oral and written exams). Also all the money and time to get the AE degree, what was I thinking.  

[Madhatter]

Sorry about the rant. I think everyone should do what they think is right for them. I have dealt with the FAA for a lot of years, I had a certified repair shop. I also used them to approve some very extensive alterations, the only ones on the planet. The new crop of inspectors are not the same, their field experience is minimal and almost all I have spoken to are not interested in LSA. That's not to say they are bad people, just new at it. To be an inspector years ago you had to have at least 15 yrs field experience, not today.  I try not to get the FAA involved unless it's really necessary and some I know are happy with that. I try to use common sense as often as I can in a regulatory environment. 

 

 

[Anticept]

Madhatter, the issue in that advisory circular is the work done by a non-certificated person part. I don't really see the point of it, but it's there. The best I can come up with is that a non-certificated person has not been tested on their knowledge to any degree, or it really is some lawyer technicality. It's just a seriously plain weird way of going about it...

I am also going to disagree with this statement: "Having to fly hrs in a test area is for unproven props not for certified props for the particular aircraft and/or engine." It's not that I disagree with your theory behind it, but rather, there are going to be cases of mismatched propellers even if everything were certified. Now if the combination has already been tested, or there is data you can use to safely evaluate if that combination is OK to use, I'm perfectly fine with that! I just DON'T like the idea of an untested combination not getting a little bit of a shakedown.

SI-912-034 (calculate mass moment of inertia) exists because of this problem with mismatched props. Metal props on a rotax engine need to be particularly careful, and there have been cases of engines being destroyed by said props. Brett at Leading Edge has told me about denied warranty claims over it.

[Madhatter]

There is over 100 CT'S flying with this prop all over the world and have discussed it with FD. You do what you think you should do on your plane. I am well past this issue and have another project in progress. Good luck.

[Anticept]

@Madhatter My statement isn't in regards to the e-prop used on a CT. That is a combination I consider tested and agree that it's not necessary.

It's untested combinations. Every piece can both be certified all day long, but if it's the first time they've been put together, I very much support testing first.

I don't think anyone here has once said they feel the testing is necessary for e-props + CTs, it's pretty much been a legality issue from the start...

[FlyingMonkey]

If I'm wrong about this, I will happily admit it.  But I have a set of operating limitations from the FAA for an ELSA in my hand right now that says that notifying the FSDO is required for any major alteration.  Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance, lists propeller changes as a major alteration.  Now, if you want to explain to me why this section of my operating limitations doesn't have to be adhered to, I'm listening.

But citing your one billion years of experience and storming off in a huff because you're challenged is not really an argument.  

[Anticept]

43 Appendix A doesn't apply to LSA, or even experimental. It's for standard airworthiness only (and parts carrying approvals even if fitted to an LSA), and any airworthiness certificates that call out for it. The FAA doesn't issue specifications for our aircraft.

Also, changing a propeller model is an AIRFRAME modification, not a prop mod. You're changing a component of the airframe, as a whole unit. It's when you modify a prop component itself that it becomes a propeller mod.

 

Quote

 

§ 43.1 Applicability.

(a) Except as provided in paragraphs (b) and (d) of this section, this part prescribes rules governing the maintenance, preventive maintenance, rebuilding, and alteration of any -

[...]

(b) This part does not apply to -

(1) Any aircraft for which the FAA has issued an experimental certificate, unless the FAA has previously issued a different kind of airworthiness certificate for that aircraft;

(2) Any aircraft for which the FAA has issued an experimental certificate under the provisions of § 21.191(i)(3) of this chapter, and the aircraft was previously issued a special airworthiness certificate in the light-sport category under the provisions of § 21.190 of this chapter; or

(3) Any aircraft that is operated under part 107 of this chapter, except as described in § 107.140(d).

[...]

(d) This part applies to any aircraft issued a special airworthiness certificate in the light-sport category except:

(1) The repair or alteration form specified in §§ 43.5(b) and 43.9(d) is not required to be completed for products not produced under an FAA approval;

(2) Major repairs and major alterations for products not produced under an FAA approval are not required to be recorded in accordance with appendix B of this part; and

(3) The listing of major alterations and major repairs specified in paragraphs (a) and (b) of appendix A of this part is not applicable to products not produced under an FAA approval.

 

Quote

14 CFR 43 App A:

(1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

 

That said, the advisory circular above also states that you use 14 CFR 1.1, which contains the following relevant section:

Quote

Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.

Clear as mud right?

[FlyingMonkey]

4 minutes ago, Anticept said:

@Madhatter My statement isn't in regards to the e-prop used on a CT. That is a combination I consider tested and agree that it's not necessary.

It's untested combinations. Every piece can both be certified all day long, but if it's the first time they've been put together, I very much support testing first.

I don't think anyone here has once said they feel the testing is necessary for e-props + CTs, it's pretty much been a legality issue from the start...

According to my limitations, any major change requires FSDO notification.  At the point I notified them (and told them it was an established and tested prop on this airplane type), they gave me a 5 hour flight test period and an area to conduct the tests.  I don't know how it would be legal to ignore either my operating limitations, or the FAA's test plan.

[FlyingMonkey]

Just now, Anticept said:

43 Appendix A doesn't apply to LSA. It's for standard airworthiness only, and any airworthiness certificates that call out for it. The FAA doesn't issue specifications for our aircraft.

Also, changing a propeller model is an AIRFRAME modification, not a prop mod. You're changing a component of the airframe, as a whole unit. It's when you modify the prop itself that it becomes a propeller mod.

(1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

Oops, you are right, duh!  My limitations list 21.93 as the criteria for major changes, which lists anything that can appreciably alter flight characteristics as a major change.  Prop still counts.

[Anticept]

I edited in more references too, to further support my statements, plus some other fun bits!

Here's a fun one: check this doc out and search for appreciably!

https://www.faa.gov/regulations_policies/rulemaking/committees/documents/media/AGAMcmmT1-01051994.pdf

Basically, there were recommendations to change "appreciably" to "significantly" because of this clear as mud issue!

[Madhatter]

I think you guys would argue with a fence post.

[Anticept]

It's a friday night, what do you expect?

[Madhatter]

[FlyingMonkey]

We own airplanes, we can't afford to go out and do anything else!