912-914

[Flybyjim]

Anyone with a varipitch control on their prop with the 912 or 914 have any advice for considering these options?

[jiott]

Airfox (Scott Noble) can weigh in on this with his 912ULS and Airmaster prop.

[Av8r3400]

War Eagle has a 914 with the Airmaster.

[Flybyjim]

Okay, so can you tell me about the performance and how this set up works, install of system, what gain if any in your cruse and did it reduce your roll out and increase your climb.

[War Eagle]

So first let me start the discussion with a few facts:

I fly a Series 7a with a Rotax 914 with an Airmaster CS with the Warp drive blades. It is a 3 blade prop with nickle leading edge and I swing the 72" diameter version.

When I purchased my Airmaster prop the Warp drive blade was the only blade offered for the Rotax engine. Today they offer other blade options but I don't have any personal experience with those.

I have only flown my bird with the Airmaster CS so I can't tell you any before or after performance stories but I can tell you how this combination performs for me.

The Airmaster is a CS prop that is computer controlled system that uses electric servos to control the prop rather than hydraulic oil pressure that is typically used in many CS props. The units come preset for take off, climb and cruise rpms for the typical Rotax engine but all settings are programmable so that you can tailor the rpm settings to fit your needs and engine operating parameters. You can manually control the prop as well as use preset computer controlled settings. The system has infinite pitch control. The prop can be feathered if you like to do gliding maneuvers with the plane. My prop was not capable of running in beta but can be upgraded as the new versions now offer that.


I fly out of an airport that is 2700' + elevation and off the deck I can pull 1800 fpm. When flying with other planes in a group I will often get a radio call like: "how about throwing me a line" or "will you order lunch for me". It's fast for a Kitfox. While I have never measured the distance it takes to rotate when I poor the coal to it, I can tell you that it's also very quick off the deck. Now I have a turbo charged engine so I am well aware some of this performance is attributed to the engine as well.

I have flown (in my plane and in other Airmaster equipped planes) against other non Airmaster systems and "it is my opinion" that you would be hard pressed to find anything that will out perform it. The Airmaster system seriously improves the performance of the Rotax 900 series engines.
I served as the purchasing agent for our EAA group that built of 13 Kitfox Series 7 planes for which I bought 8 Airmaster CS props and we installed them on 3 Rotax 914's and 5 Rotax 912ULS engines.

While there aren't many 914s in my neck of the woods there are a lot of 912s with all kinds of prop variations from ground adjustable to in flight adjustable.

While it would not be a rational compare for a 914 to fly against a 912s, I have flown in 912s (with an Airmaster CS) being challenged by a 912s with IVO inflight adjustable prop. The Airmaster equipped plane with 2 souls on board could allow the IVO equipped plane (with only the pilot on board) become airborne and clear the end of the runway before we started our roll out and we could catch and overtake IVO equipped plane.

The Airmaster really allows you to maximize (or fine tune) the engine performance so that you can maximize the aircraft performance.

They are a little spendy, so you have to really want one, but they work well.

[Flybyjim]

WE,

Thank you for the report, this is the type info that will be very helpful justifying the cost with that type pf performance. As with most things in the hobby wants sometimes come with high cost but one only goes around once in this life time so why not!

I have not yet received one report when the owner of the air master was dis-satisfied with the operation and performance.

Thank you for taking the time to send the report.

Jim

[Dorsal]

Curious, do you fit the blades to the hub or do they do that?

[War Eagle]

Curious, do you fit the blades to the hub or do they do that?

The Airmaster assembly uses the standard Warp drive blade but the hub assembly for the prop is a larger diameter than the standard Warp drive hub. So in order to maintain the 72" swing the standard blades are shortened (on the hub end) about an 1.5'' and then they are fitted for the bearing and hub lock assembly that fits inside the Airmaster hub.

Airmaster cuts the blades and does the minor machining that is required on the hub end of the blades. They also balance the whole assembly. Then in the install process I assemble the blades and lock them into the hub, do the setup adjustments and then go fly.

[War Eagle]

Here are some pictures of the install for my Airmaster.

[SkySteve]

War Eagle,
Your plane is just hands down beautiful! And, thanks for taking your entire prop assembly off, cutting your spinner in half and mounting it all on a tripod so we could see it! :eek::D Now put it all back together and go fly!;)

[Flybyjim]

A big thank you for the photos and info, I can't stop druling

[Av8r3400]

Having just gone through all the grief I did concerning my gearbox, I believe it was caused by exceeding the mass moment of inertia rating for my early model gearbox.

Has anyone ever done this test (http://www.rotax-aircraft-engines.com/portaldata/5/dokus/d02941.pdf) to the Airmaster prop to determine the long term effects of such a heavy (albeit very high performing) propeller system?

[War Eagle]

Having just gone through all the grief I did concerning my gearbox, I believe it was caused by exceeding the mass moment of inertia rating for my early model gearbox.

Has anyone ever done this test (http://www.rotax-aircraft-engines.com/portaldata/5/dokus/d02941.pdf) to the Airmaster prop to determine the long term effects of such a heavy (albeit very high performing) propeller system?

The answer to your question is yes. The test was not done by myself but by Airmaster.

The system I have is the AP332 with the WD blades. I'll try to tell you what I have been told in relationship to this line of questions.

The largest WD blades do exceed the stated limit from Rotax as they are heavy at the tips. As I understand, all other blade types are below the the limit of .6kgm2. As an example the tests show the AP332-WDT68R is .595kgm2 and the AP332-WDT72R is .68kgm2 and my setup comes in between those two at .6kgm2.

As I understand there have been no reported gearbox failures due to MOI issues on any installed Airmaster setup. There has been some discussion as to whether it reduces the life of the sprag clutch but there hasn't been anything presented that is conclusive (a couple of units in question). As I understand, more important issues related to the sprag clutch can be things like starting, balance of the carbs and use of the soft start.

Airmaster has communicated to me that they have not received any reported issues related to the MOI and they have over 900 units in use on Rotax engines.

Their recommendation to me has been to avoid wide cord blades at diameters over 68 inches. If you need a wide cord blade over 68 inches then they would suggest using lighter blades than the WD. You must also consider service life if you are considering lighter blades.

Airmaster reported their most popular model of the Airmaster system is the AP332-WDT72R. Airmaster has said this model is used extensively in Russia and South Africa on the L-42 and the Sling.

http://en.wikipedia.org/wiki/Chaika_L-4

http://airplanefactory.co.za/models/sling4

Of the 8 CS props we have used on the Kitfox planes we have nearly 3000 accumulated hours with the single highest approach 1000 hours and there have been zero gearbox related issues. Airmaster has so many of these units in service that if there was really a problem out there it would be hard to cover it up.

[War Eagle]

War Eagle,
Your plane is just hands down beautiful! And, thanks for taking your entire prop assembly off, cutting your spinner in half and mounting it all on a tripod so we could see it! :eek::D Now put it all back together and go fly!;)

Do you think if I use Hysol I can put that thing back together again and make it good as new? http://www.teamkitfox.com/Forums/images/icons/icon12.gif

[Pingert]

As per props I have an airmaster prop on for 230 hrs no problems would not have any thing else have a 914 turbo kind of beefed up put out around 130hp plus manifold on boost to 39 inches to 8000 and 36inchs to 13000ft lift off always around 250ft at 2800 elevation and that's no BS
But my guestion is has any body having issues with hot starts after shutting down seems to vapor lock is there any little tricks to start!!!!!

[Av8r3400]

Do you have the return to tank line installed in your fuel system? (I don't know if that is an option on the 914.)

This does a lot to help solve vapor lock on the ULS motors.

[Pingert]

Thank you for reply yes have a return line from header tank back to right tank so what happens is the return from engine goes to header tank and excess back to right tank wonder if there's an other way .But one of the ways I manage it is to shut off fuel and cool turbo down for approx. 2min. but still hard starts some times.:confused:

[Paul Z]

War Eagles Veg-O-Matic It slices and dices. :)

That is one nice Airplane!

https://www.youtube.com/watch?v=1GniNeqSX5U