Alright- I am trying to wrap my head around everything real quick.. I do not personally handle certification so I am asking the guys here and getting an information overload.. Let me see if I can correctly regurgitate what I am being told:

We are ASTM approved (approved? certified? compliant? one of those words) for Rotax engines. As I understand it, under the new rules, a manufacturer can take a look at our data and decide that the propeller meets their airworthiness requirements, in which case no further testing is required. They may, however, as you said, wish to see performance data specific to their aircraft, in which case flight testing would have to be done. Full disclosure- I am the "marketing guy" here, and an American, and I am trying my best to understand what my very technically minded German colleagues are explaining to me (in German!), and then pass that along here.. there is bound to be something lost in translation, and for that I apologize in advance. I have also passed your question to our American partner (who has been in the aviation business for longer than I have been alive) and as soon as I hear back from him, I will hopefully have something smarter to say : )

In my certification work, I do not [yet] work with the ASTM nor MOSAIC standards. I'm not familiar with those standards, nor the standards applicable to non certified airplanes. But, I do know that physics don't change because of how the airplane has been authorized to fly. The Part 23, 33, & 35 certification standards are very well thought out, and the result of some painful and expensive lessons. If you need to "do it differently" from those standards, you really want to consider all of the implications.

While doing flight testing for propeller change STC approvals on GA airplanes, I have found a few things which were pretty important to understand, and could be an indicator of a reduction of safety, if not correctly compensated or mitigated. In my flight testing of a Bellanca Scout, I found that replacing the metal propeller with a composite propeller allowed airframe and in particular, horizontal stabilizer vibration which was worrisome. I researched this and found a report of similar observations with a composite propeller change to a Citabria in England in 1992. That could be an unsafe condition, as on those airframes, the metal propeller acted as a "harmonic balancer" for the whole airplane, and when it was taken away, undesirable vibrations were possible.

As I have mentioned, a propeller change can dramatically change the gliding characteristics of the plane. If the characteristics have been changed, this needs to be understood from results of good flight testing, so that pilots know what to expect, and how to handle the plane in the case of engine failure

Composite propellers (including wood) are generally not subject to installation limitations to engines the way metal propellers are, though having a good understanding of any vibration vulnerabilities is still important. There have been a lot of hard lessons learned, some over longer than obvious periods of time, in the realm of propeller vibration, so it's worth understanding well for the combination you propose.

In general, what word used depends on the aircraft category and whether it falls under a Standard AWC or Special AWC. For an S-LSA, it would need to be compliant to an FAA accepted ASTM standard. However, that level of compliance is determined at the aircraft level under their Letter of Compliance to the FAA.

They do that now under the current rules. My point is you stated your plan was to approach the individual owner before the manufacturers. However, without the OEMs acceptance first, the owners cannot install your prop per the old or new rules without additional requirements or authorizations.

Not quite. You are intermixing requirements between different aircraft categories. Perhaps research the different requirements between an S-LSA, and E-LSA, and an experimental amateur-built (E/AB) aircraft, or discuss this with your American partner. All have unique requirements to use your new props.

That is something that I- being woefully underqualified to make such determinations- must leave up to our engineers and test pilots.. To the best of my knowledge- we have not experienced any such issues with this particular propeller yet. We have been manufacturing propellers in multiple fields for over 30 years (EVTOL, UAV, paramotor, trikes, gyros, UL & LSA aircraft, etc..)Naturally, we do significant testing with all of our propellers. I can say that with our long history with experimental EVTOL's and UAV's, we are particularly well versed in vibration mitigation- it is a topic that comes up often when talking about vehicles that must withstand rapid changes in direction and acceleration (also worth noting that those propellers are often 2-3 meters in diameter). Long story short: I may not personally have the technical expertise to address your concerns- but this is not Helix's first rodeo.

I've got a meeting with one of our engineers and our american partner this evening. I will bring all of this up with them. I am 100% certain they are both very aware of the challenges, but if it helps me understand and give better answers, then it's worth discussing. I will be sure to update you.. probably on monday.. nope- dangit.. all these german holidays.. tuesday! I'll be back on tuesday- hopefully smarter than I am today : )

Just wanted to drop a quick update- I must once again apologize for not being the most knowledgeable when it comes to certs, etc.. but our American partner in this particular venture is Bill Canino. He is both FAA DAR, and on the ASTM committee responsible for submitting the rules proposals to the FAA. That is only to say that he is well versed and aware of what is happening and what needs to happen.

Many apologies for the delayed response- I needed to make sure it was ok with Bill before I mentioned him by name.

Then perhaps sit down with Bill and educate yourself on the requirements to install your prop on US based LSA and amateur-built aircraft. MOSAIC has the potential to reverse the decline in the Part 91 sector here plus provide an opportunity for EU based LSA centric companies like yourself to expand here as well. However, you only get one chance to make a 1st impression and some of your comments in this thread, and on other websites as I understand, may "tarnish" that impression. Regardless, best of luck with your endeavor.

You are welcome to contact Bill directly if you want to chat with him about requirements. Send him an email at [email protected]

Let me know if you'd like to test out the propeller (no promises- but maybe we can set something up), or just want to talk about our current performance test results.

No need. My comments are only suggestions specific to your marketing posts here and on other forums concerning how you plan to introduce your props to the US market. I think you are underestimating your target market and why they fly LSA or E/AB aircraft especially when you bring up “certified” installers or changes to aircraft Phase 1 requirements into the mix. While you did gain traction with your proactive marketing approach, you have created more questions than answers at this point and not all positive I’m afraid. So while I have no requirement for your props, I have heard and been questioned on them which led me to reply to you here with what I have seen and heard in other places. How you use that info is up to you. Again, best of luck.