Airmaster

[Skippydiesel]

Anyone had any experience with , comments on, the Airmaster/Whirlwind AP332CTF-WWR64W ?

https://www.propellor.com/airmaster-factory

[lakespookie]

I think you meant https://www.propellor.com/ that being said in most cases unless you have a really good reason to transition to it in general they are overkill for our airframes where simplicity is a better option, but as some examples, for those of us exploring higher horsepower engines in the 130-160 range, the ability to tune the prop across the power band will gain a net performance/efficiency boost and limit the compromise between takeoff and cruise performance. On the lower end it just does not make much sense, A similar driver in these kinds of engines is the lack of prop clearance to maximize prop efficiency due to ground clearance resulting in needing to use a 4 blade prop in order to maintain ground clearance and get adequate usage of the power on climb, by going adjustable you can go back to a 3 blade. two diffrent drivers for addressing the same compromise, i.e. Climb vs Cruise at the end of the day unless you are planning alternative power solutions the compromise is just not as large is there a benefit to going to an ajustable on a jabiru at 130 closer to like 120 contious(Working from memory so i dont remeber the exact numbers) yes but is it worth an extra 10-15k i.e roughly the cost of the motor + the increased failure point and complexity? In most cases i would say the answer is no. espceially considering that most of us are drawn to this airframe due to the cost factor.

YMMV, I have thought about it mostly because i am planning to put a 150HP engine in the front for High Altitude performance and the desire to have very high cruise speeds in smooth air, among other reasons but i am also putting the experimental into the configuration of my aircraft, realistically in cruise with that kind of power available it addresses the cruise v climb compromise and would permit going three blade instead of 4 which reduced the induced drag in cruise, even then i am not sure the cost makes sense. if you are building to plans I would say it def does not make sense.

P.S. Never exceed the designed aircraft limitations especially not VNE Flutter is not something you ever want to have real world experience with.

[Skippydiesel]

Thanks for all that including my incorrect web reference (now fixed)

I am contemplating the purchase of an unfinished Sonex project, which will come with the Airmaster/Whirlwind AP332CTF-WWR64W and a Rotax 912 ULS.

The Airmaster weights 11.5 kg and 64 inch blade (swept arc?)

I am wondering about prop weight for the Rotax, C of G, ground clearance, etc etc. Of course some idea of performance would be great - I would expect markedly better take off/climb with some increase in high speed cruise, perhaps a bit more econamy .

[lakespookie]

Considering the rotax tends to be under weight the adjustable prop will probably help you with CG. The best way to verify clearance is to measure it yourself i think the 64" prop blades might be a bit large to have adequate clearance. The prop sonex offers for the rotax install is 60" so you have to find extra clearance somewhere. You have one of several options on that front modify the gear to accept larger tires that will buy you a bit of clearance but even with that I would plan on having to replace the blades, warpdrive will be able to provide blades as small as 60 inches which will match the recommended size sensenichs smallest offered blade size is 62 I believe. Either way you might be able to trade or sell off the old new blades and its hard to beat a 10k+ propeller system, As far as performance that really depends on how you configure the prop in different modes. In all honesty the prop system is probably a bit of overkill for a 912 but it will get you better performance how much i cannot quantify maybe someone else on here has had an airmaster on this airframe as far as i know no one has.

[Zack]

The EAA recommend 9" of ground clearance for the propeller on a tail wheel aircraft.
https://www.eaa.org/eaa/aircraft-building/BuilderResources/while-youre-building/building-articles/propellers-and-spinners/the-fixed-pitch-propeller-dilemma?

Next, you must establish the maximum propeller diameter your airplane can accommodate. Determine this with the aircraft in a level (take-off) attitude. Measure the distance from the crankshaft to the ground and subtract 9 inches to allow for safe ground clearance. For example, if the hub-to-ground measurement is 45 inches, subtracting 9 inches will leave an effective radius of 36 inches. This limits your maximum allowable propeller diameter to 72 inches (36" x 2" = 72"). Incidentally, if you are the proud owner of a nose gear equipped aircraft, you have another concern. In the event the nose gear shock strut collapses, or the tire goes flat, will the remaining ground clearance (allow 2" to 3") be sufficient to save the prop?

The factory centerline height as determined by measuring the plans is 39". 9" for clearance in level flight leaves 30" or 60"diameter propeller. My centerline height was higher in part because I installed my main landing gear flush in the engine mount tubes. The plans call for 16 43/64" vertical height to fuselage, but my installed height was 17 1/8". 17.125-16.6719 = 0.4531 extra height, 0.4531 * 2 = 0.9062 propeller diameter increase. However, my ACTUAL height in flight attitude was 40.7". This is what I calculated with this figure, you can substitute in your actual centerline height:

Maximum propeller diameter with 9" ground clearance:
40.7 - 9 = 31.7
31.7 * 2 = 63.4"

Ground clearance with a 60" propeller?
(60/2) = 30
40.7 - 30=10.7

Ground clearance with a 62" propeller?
(62/2) = 31
40.7 - 31 = 9.7

Ground clearance with a 63" propeller?
(63/2) = 31.5
40.7 - 31.5 = 9.2

Ground clearance with a 64" propeller?
(64/2) = 32
40.7 - 32 = 8.7

Ground clearance with a 69" propeller?
(69/2) = 34.5
40.7 - 34.5 = 6.2

I chose a 62" diameter M-T propeller, which is in production now. This is a conservative choice, as I could have specified the maximum diameter of 63.4" if I wanted. I wasn't sure how much the landing gear would deflect with a completed firewall forward. If you need additional height you can also increase the wheel / tire size. I calculated that as well.

The stock wheels for the mains are Azusa 5" wheels. Stock tires are 4.00 x 5, although the Azusa 5" wheels will accept 5.00 x 5 tires. 11-400 x 5 Azusa 7046-8 are stock tires, 8 ply, 10.8" diameter 7131 innertube. The Michelin Condor 5.00x5 tires have are 14.20" - 13.65" in diameter, per the vendor. https://shop.desser.com/5.00x54plymichelincondortire/ecomm-product-detail/323568/ I've purchased them, but I haven't installed them and I don't have actuals. It's been reported here that 5.00x5 tires will fit in the wheel pants but I can't personally attest to that. Changing from a stock 11-4.00x5 to 5.00x5 tire will result in 1.575" extra height.

I hope this helps you or someone else who finds this.

[Zack]

When I bought my kit in 2011 I had planned a JabIru 3300, so when I changed directions to Rotax I used that 3300 as a comparison. The 3300 had a published weight of 184 lbs, the solid spinner was 2.8 lbs, the propeller was approximately 8.5 lbs and the old battery (Odyssey PC680) was 13.45 lbs. Total package adds up to 208.75lbs. I couldn't figure out how this fell under the 200 lbs FWF limit from Sonex, but IIRC the 3300 did get heavier over the years.

This is the package I chose. The Rotax 912iS is 150.7 lbs, the three blade CS MT propeller is 19.4 lbs, the governor is 2.2 lbs, the spinner is 2.2 lbs, and the EarthX ETX-900 battery is 3.9 lbs. Total package adds up to 178.4 lbs.

Keep in mind I didn't weigh everything myself and relied on published figures. Also, the final installations will vary based on many different variables. Still, I felt comfortable being 30 lbs under the 3300 total and 21.6 lbs under the FWF limit. I don't know what the CG will look like with the weight further forward due to the propeller and governor.

The iS is 13.7 lbs heavier than the ULS, so you should have even more room under the FWF limit. The ULS with a lightweight fixed propeller might have CG issues in the other direction, it's that light. It's about the same as a JabIru 2200. The ULS and airmaster seem to fit right in the middle.

[Skippydiesel]

Great information gentlemen. My thanks.

[Skippydiesel]

My Sonex/Rotax/912ULS/Airmaster CS, is now up to 45 hrs.
I will be taking it home at 50 hrs to do major surgery to the cooling system.
My existing (a little too innovative) coolant Radiator is mounted directly below the fire wall and is incorporated into the belly shape of the cowling.
The radiator works well in flight,with head temperatures as low as 89C. Ground opps are a problem, with head temps normally rising to about 110, occasionally 120C, depending on ambient conditions and how I manage the aircraft on the day (long, short taxi, holding).
Oil temperatures are my biggest worry - ground opps are not a concerns, even in flight, during prop Climb mode, oil Max 104C. Its when I switch to Cruise mode, the oil temp just slowly climbs and climbs - if I do not cut power & descend, it will go over 120C. A range of air flow "improvements" has dropped (with constant vigilance) the oil temp to between 104-110C. Getting the rpm/MAP "square" helps however this can only be done in Manual override (will need to change controller settings)
My constant Cruise, oil temp target is 95C
What I have deduced:
The aft radiator is dependent on air from the cowling. The radiator & surrounding support system is essentially restricting exit air, pressurising the cowling and reducing the effectiveness of oil cooler and on the ground, air flow to the cylinder/head barrels.
My Airmaster CS is "loading" my engine to the point where the heat generated can not be easily controlled by the Rotax "Large" oil cooler.
I am investigating the Rotax "Extra Large" oil cooler
I will be relocating my Radiator to a position near the front of the cowling. This will open up the exit air, hopefully generate a little under-cowl negative pressure, to encourage air flow .
Oil cooler relocation is yet to be decided but may be in the exit air flow (cowl belly again) but not blocking, as the Radiator was.
The Airmaster prop controller will be programmed, to allow engine WOT rpms to be 100 rpm below Rotax recommended max (currently 5300 rpm in Cruise)

[lakespookie]

I assume you are going to get an amendment to your airworthiness cert since you will probably have to kick it back into phase 1 for the cooling system modification.

That being said its great to hear you are flying and things are going well it would be interesting to hear what kind of performance improvements you can quantify once the cooling is dealt with and the prop controller is tuned.

[WaiexB22]

Skippy - Are you overall happy with your experience with the airmaster? Are there any "gotchas" or things I should be aware of. Has customer support been good? (so far, I have been super impressed with their sales/technical department). They have recommended a few options, but I am strongly considering a 64 inch diameter 4-blade with whirlwind blades for my application (it seems to be the best for my unique combination).

Is your airmaster fully feathering? if so, do you see a notable gain in glide performance with the prop feathered?

Is it easy to program and adjust?

What diameter spinner did you run?

Thanks!