Airmaster Propeller

[DocRon]

Have any of you out there installed an Airmaster Electric Propeller on  your aircraft?  I'm trying to find out the size of spacer/flange in front of the gearbox and the length of the spinner for this.

[Roger Lee]

Hi Ron,

It is an LSA. No variable pitched props. If it was legal don't you think hundreds would have already done it?

[Anticept]

Hold that thought though.

While I expect the upcoming NPRM won't have as much as we hope, maybe, just maybe, it will remove some of the more oddball limitations that prevent us from using better propellers.

[Roger Lee]

But I bet that decision is 2 years out.

 

And if you go against the system you may not find a mechanic willing to do an annual because then he's on the hook.

[Tom Baker]

Kind of a grey area, but the regs say in flight adjustable. Could it not be installed if the adjustment controls were not accessible in flight?

[Roger Lee]

I have heard of 2-3 people who may have tried this on the internet and unless your caught or something goes wrong you may get away with it, but you're playing with fire and may take it in the shorts if something happens. Who knows if they really went through with it.

Plus you'd still need to find a mechanic who would either install or even do an annual. Personally I wouldn't touch it. The liability to the FAA and a possible civil suit is too high. You might as well cancel your insurance to.

[Tom Baker]

Why all the doom and gloom Roger? If you truly can't adjust it in flight it would be perfectly legal, assuming it is not a constant speed propeller. You would however be able to quickly optimize it for the flight profile of the day. One setting for roundy rounds in the pattern, and another for high altitude cross country.

[DocRon]

I was told Monday that Edsel Ford, AFS-610, the guy at FAA-Oklahoma City who writes LSA rules, told the DPE at Marana that you could put an in-flight adjustable propeller on a E-LSA providing you placard the panel saying you are not to adjust it in-flight.

So, I'm seriously thinking about doing it.

So, if Roger cannot in good conscience sign off my annual inspection I can respect that.  I would still ask him to do the inspection yearly with no logbook entry.

[Tom Baker]

1 hour ago, DocRon said:

I was told Monday that Edsel Ford, AFS-610, the guy at FAA-Oklahoma City who writes LSA rules, told the DPE at Marana that you could put an in-flight adjustable propeller on a E-LSA providing you placard the panel saying you are not to adjust it in-flight.

That's how the Carbon Cub gets away with being an LSA with a 180hp engine.  It is placarded with a notation not to exceed 120 knots.

So, I'm seriously thinking about doing it.

So, if Roger cannot in good conscience sign off my annual inspection I can respect that.  I would still ask him to do the inspection yearly with no logbook entry.

The prop is a little different than what Carbon Cub does.

BTW a Carbon Cub will not go 120 kts even with 180 HP. The reason for the power restriction on the Carbon Cub is to meet the minimum empty weight for certification as a SLSA.

[DocRon]

OK, I'm sorry I ever brought this up and I certainly won't again.  I talked with the EAA LSA specialist and he liked the idea but could not say yes or no.  So, I will write Edsel Ford and get an official answer back.  So, let's just close this out and never think of it again.

[Anticept]

14 CFR 1.1 has the definition for light sport. It applies to both S-LSA and E-LSA.

You will also find an airworthiness limitations section on your LSA airworthiness certificate.

Both of these will have the information about propellers and why you cannot use an "in flight adjustable prop."

[Roger Lee]

"Why all the doom and gloom Roger? If you truly can't adjust it in flight it would be perfectly legal".

If you can get this in writing I'm all for it. If it isn't in writing somewhere then it's just a best guess. If that person is wrong that you get the info from guess who has to eat the fines and sanctions. This has been all over the internet for 10 years. Why don't you see a bunch of people doing it?

 

If it can't be adjusted in air then it is nothing more than a an easy ground adjustable prop. You either set it for climb on the ground or cruise , but you don't get to mess with it in the air. So the variable pitch is almost worthless. Then it would still fall back on where is the best all around rpm. 5600-5650 where we already are. It would be a waste of money unless you get to use its full function.

 

Why spend $8K on something you can't use as prescribed. 

[FlyingMonkey]

On 9/6/2018 at 3:25 PM, Tom Baker said:

The reason for the power restriction on the Carbon Cub is to meet the minimum empty weight for certification as a SLSA.

Wait...what?  How does limiting power decrease empty weight?

[Tom Baker]

4 hours ago, FlyingMonkey said:

Wait...what?  How does limiting power decrease empty weight?

It doesn't. What it does is lower the amount of fuel that is required to meet ASTM standards. By going from 180 to 85 they only need to carry 42.4 pounds of fuel instead of 90 pounds, plus 2 190 pound people.

[FlyingMonkey]

On 9/7/2018 at 9:30 PM, Tom Baker said:

It doesn't. What it does is lower the amount of fuel that is required to meet ASTM standards. By going from 180 to 85 they only need to carry 42.4 pounds of fuel instead of 90 pounds, plus 2 190 pound people.

Ah.  That makes more sense from, you know...physics.