skippydiesel

I forgot to mention - I have politely challenged the Airmaster recommendation of a 3 blade. They have come back to me, agreeing that the 2 blade may be a better bet.

I find myself a little discomforted by their rather too quick & easy capitulation and have sought further debate/argument - have heard no more at this time..

Thanks for all that - I thought the auto stuff was probably OK . Now I am sure.

Looking for a small quantity of Chrome Molly tubing . I dont work very well in Imperial, so have supplied dimensions in mm with my best guess in inches (Taken from variose charts):

About 1 m of OD 15.88 mm (5/8") x ID 0.534 mm 0.527") Wall 1.24mm ( 0.049")

About 500mm of OD 31.75 mm (1 1/4") x ID 28.7 mm (1.134")  Wall 1.47  mm (0.058")

I have taken my measurements in mm - checked out variose charts and "rounded" my  figures to the nearest/best guess listing.

Is it okay to purchase off automotive suppliers (rather than aviation) ?

Also

To fit inside  31.75 mm tube - I need to install (weld in place) a dividing wall, washer shaped piece of flat circular metal, with a 16 mm hole in the centre -  can this be purchased or do I make it ?

1 hour ago, cscotthendry said:

Also check blade tracking. Getting the pitch the same on all blades is only half the job.
Chock the aircraft against movement.
Put a chair or a ladder near the prop, but where the prop can be turned without hitting the chair.
Turn the prop bringing each blad near the chair and measure the distance.
There are specs (RA Aus tech manual?) for prop blade runout, radially and axially.
The above is easier to do if you remove 1 spark plug from all cylinders.

But as Mike said, pneumatic synching of the carbs is a major cause of RPM related vibrations.

Agreed - one one point I would differ slightly - I do my tracking check against a pointer (small piece of wood/plastic/even stiff cardboard), taped securely to the nose wheel fairing.

Rotate prop so tip of one blade nearest point to nose wheel.

Move pointer to within known distance from prop tip. Secure pointer with tape.

Rotate prop & observe each blade tip clearance to pointer.

By using a part of the airframe, there is little concern that aircraft movement might influence the test.

Too bad about the Monnett family attitude - If the Sonerai does not evolve, it will ultimately disappear from the sky and become a footnote in the history of small aircraft aviation. I will certainly "check out" the Sonerai Forum

Years ago a conversation on this Forum alerted me to collecting stuff in your aircraft.

Went out and removed ALL non essential stuff (some of which I had forgot about) - it added up to kilos of not so good ideas to have on board.

Probably all crept back by now  but for at least 6 months my little  aeroplane must have had much better performance.

Great idea! Hope something comes of it.

1 hour ago, rhtrudder said:

Thinking of replacing the prop studs and the flange bushes are they available from floods or the propellor mob

Dont know what your prop flange system looks like but mine has separate blade "root" /hub socket clamping to the flange securing bolts. This means that I can clamp the blades in the selected pitch without fear of making an inadvertent change when I tighten the 6 x 8 mm flange bolts. I always tighten progressively, using an accurate torque wrench, to minimise the chance of distortion. 

Your LAIME should be able to advise on what needs replacing. If your prop was a hollow composite, there may be little if any damage to the hub & "studs"/bolts.

My aircraft uses "off the shelf " Allan key " head, 8mm HT bolts and lock nuts - much cheaper than buying from BF

1 hour ago, onetrack said:

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Sobering reading. Reinforces the need to be acutely aware of W&B for every "sortie" where weight limits may be be very close/above max OR where a single weight (large person) is boarding.

My aircraft is supposed to be able to accommodate 2 X 90 kg persons. I am a shrimp at about 70Kg, fully dressed for the cold, so when I get a large passenger (anyone 90 kg or over) I start to be concerned about  lateral trim, TO/Landing distances & speeds - Sorry but I dont take passengers of 100 kg or over, even though the aircraft is technically within weight limits.

Cause I'm anal, I use several different devices to check/adjust pitch:

Alan key, spanners, accurate torque wrench to loosen/tighten hub fittings

Tin of  Carnauba wax polish 

• Lubricate blade hub socket (only need to be applied at first adjustment)

Masking tape

• Wrapped around blade at approximate measuring radial (dont forget to remove befor engine start)

Steel metre rule

• Used to make accurate measurements from, pre scribed,  centre of hub to recommended measuring location on each blade. I make two measurements/blade - hub centre to leading edge and to trailing edge.

Sharp pencil & short strait edge

• For marking a strait measuring line/location, between above marked points,  on masking tap

Nice builders level

• Set the hub/blades to exactly vertical for each measurement. I do all my measurements on the left side of aircraft so blades must be rotated 180 degrees

Digital protractor

• Have fitted with straight edge that can be clamped exactly to blade measuring point/line. Protractors (both) are "zeroed" against vertical face of hub before each measurement/adjustment

Warprive bubble protractor

• Rough check/adjustment befor using digital protractor

Home made wooden "clamp" (2 pieces of  wooden strip, hinge at one end)

• Clamped (hand grip)around blade to give leverage & additional control in making fine rotational adjustments of blade

With all of the above I am able to make accurate adjustments down to better than  .5 of a degree

Hi Rhrudder- dont have a 914 (wish I had)but do have a 912 ULS so may be able to contribute a little or could be all fake news

In my application I took a great deal of time & trouble to static balance, pitch and then dynamic balance my 2 blade Fiti prop. Ran like a sowing machine from the static balance/pitch onward, so noticed little change with the dynamic balance. I guess I am going the long way about suggesting you may have been a tad hasty in your temporary re propping.

I would also second Blueadventures suggestion again you can only benefit from aa precise as possible pneumatic balance of the carburettors.

One other point - check out your engine mount & rubbers for nil damage/security

Great stuff Robin

What amazes me is the performance of your creation. Its not just the speed,  its the econamy/range, the low stall -  the doing of so much more with less - very much the subtle sophisticated approach to aircraft design/power - as apposed to the just add a bigger donk & brick will fly philosophy.

I run the same engine, Rotax 912 ULS, in what most of my compatriots would consider to be a reasonably slippery airframe, ATEC Zephyr (Vne 143 knots Vso 30 knots).

We can achieve 120 knots, at sea level, but my ground adjustable prop runs out of thrust at that point (pitched too fine). I am exploring my prop options to try and maintain my absolutely essential short field performance (dodgy home strip) while opening up my cruise.

Seems to me a CS prop is my only option. I note that you have selected a 3 blade this time around ?

The " boys"  of the Forum most of whom appear to be lovers of low & slow, seem reluctant to offer much in the way of critical support .(See This Forum - Engines & props) So any advice will be most welcome.

I have contacted a number of CS prop suppliers, Airmaster amongst them. Airmasters response was fast & professional but has me feeling that their recommendation might be a little generic, in that there was no questions on either my aircraft or my goals for it -  I have asked for their recommendation rational - we will see.

Got to go! granddaughter demands!

Ha Ha! its great to hear the jokers are all on song.  By all means have your fun but have you read about Robin Austen's most recent masterpiece VH-SRS,  in General Discussion VH-SGS Soneri II -

Look what you can do with a humble Rotax 912 ULS & a CS prop and a massive dollop of talent

• Max continuous cruise speed 173 Kts

• All day everyday cruise speed 165 Kts (24”/4800rpm)

• Economy cruise - 160 Kt at 15.2 L/hr 

• Aerobatic +6G -5G

• VNE 180Kts (testing included full range flutter testing up to and including 200Kts)

• 300Kg empty - 600KG MTOW – 300Kg payload 

•  

• Stall speed slightly less than Sonerai II (minimum solo 39Kts)

• 1250 NM range at 160 Kts 

• 1700 NM range at 100 Kts 

• Also comfortable at 70 or 80 Kt “loitering” speed

• Constant speed propeller with latest Sensenich high speed blades

• 23” prop clearance for gravel strips

• Full span (30 degrees deployment) electric flaperons

• Horizontal Stabiliser - electric inflight adjustable

• Rotax 912 reliability and operating costs

Puts are plebeian effort into perspective

Robin, You are  genius par excellence. How is it that you can alone seem to be able to deliver such whole of aircraft efficiency, when the rest of the light aircraft world continues to squabble about the size of the engine or how "sexy" the aircraft looks.

Four questions:

• You have told us the prop blades are Sensenich - iI assume the hub is from a different supplier, are you at liberty to name them? (supplementary Q hydraulic or electric control/governor?).
• What might be your estimated ground role? and climb speed/rate?
• Rotax 912 enhancements ?
• Will you be supplying plans/kit/factory aircraft any time soon?

RF - You have it in the "nut shell" - Will I get a significant increase in cruise performance, while preserving my already excellent TO performance????

My own Airmaster enquiries have been responded to with great efficiency HOWEVER they seemed somewhat generic to me. I have written back asking for a justification of their recommendation - I wait in anticipation of their reply.

The quote(s) from Airmaster were in the $11+k range, including delivery but not GST.

In the mean time I have contacted MT-Propeller who have responded equally fast but with a different emphasis - They require a detailed questionnaire to be completed on all matters regarding the subject aircraft (so far a bit different to Airmaster). 

Turbocharging ?? - Hmmmmm??? I am a diesel freak, so am enamoured of turbo charging, as a way of improving volumetric efficiency, while potentially reducing pollution (cleaner burn) BUT turboing an engine not specifically designed for it, has a whole range of potential problems that must be addressed, if you are hoping for significant power increase and service  longevity/reliability of the engine. In short, no matter what anyone says, its not a magic bolt on power improvement

All kudos to JG3 - the scientific resources that are available to this forum are astonishing.

I focus on his Eprop work and haven't read all the way through his historic test analysis & conclusions.

I have jumped to my own conclusion - this is how a comparative study should be done, rather than the subjective and at times emotive testimonials' we have had served up to us.

My only observation would be - how would these figures change (if at all) if the sample propellers were mounted on a less "draggy" (speed limiting) airframe ???

1 hour ago, RFguy said:

Of course the  unwanted configuration of that Bolly CS prop in the previous post should be taken in context- all R&D, and shouldn't reflect anything, since we  know few facts.

 

After flying in a CS prop aircraft yesterday,  an RV, and seeing the additional workload for all but a simple flight (takeoff, cruise, land)  I think you have to really , really want it, to justify the large increase of complexity compared to a fixed prop. 

 

SkippyD, may I naively suggest  a coarser prop and a turbo  on your Rotax to improve your short takeoffs ????  There are a few 912ULS engines around with non factory turbocharger setups on them. They're only very small turbos...Or get a 914... You don't need alot of extra performance....

 

 

Thanks RF - I dont know where/when the perception that I have a TO concern has come from - "Fake News" - couldn't be further from the truth. My sub 100 m ground roll and 1500+ft/min climb out is okay with me - I am looking for a higher cruise speed while maintaining my TO performance

Refer your comments on CS Prop Management - As a fugitive from GA I have my CS endorsements, so am well aware of and accept the additional knowledge/skills required BUT (isn't there always) technology can, if you choose, make the demands less - if you purchase one of the electric prop control systems, it is (almost) as simple as selecting, using a rotating knob/switch, TO - Climb  -Cruise - Hold (econamy cruise). Its a good idea to have a manifold vacuum gauge but not absolutely necessary (unless you start to use the manual adjust) Not too onerous in my book.

1 hour ago, RFguy said:

 

 

 

 

 

2 hours ago, Kyle Communications said:

mid 2021 she says so you might have your nosewheel fixed by then 

 

I wish it was just the nose wheel BUT look on the bright side without the insurance  $$$ I would not be fantasising about propeller selection

31 minutes ago, Kyle Communications said:

Just had a email back from Eprop...they will be offering a manual and a electric and a hydraulic system for their units

Good-oh! Sooner rather than later I hope.

10 minutes ago, FlyBoy1960 said:

The Bolly in-flight adjustable is being tested/developed at our airfield. There have been a couple of blades that have let go and the other day (about three weeks ago) the propeller went into beta mode at about 200 AGL after rotation requiring the aircraft to crash land into a pond. I am not sure if they are going to keep going with the project

Wow!!!!!

Great video - Bolly seems to be doing the job but cant find one anywhere on the web

From a purely philosophical position I am all for KISS.

As usual I have what I would call mitigating factors that degrade the simple approach. So when it comes to propellers, I am reluctant to move away from my ground adjustable that has served me so well, to something as complex as a CS prop, so may be a (manual) in flight adjustable may be a good compromise. I certainly would not rule it out - suggested suppliers ?

2 minutes ago, Kyle Communications said:

As far as punch in my comments...I just can not justify the cost of a CS prop as I said so its never really been a big thing in my front of mind. Of course there are plenty of people around that have the bucks and good luck to them but my bank balance is stretched far enough

 

As I said, I agree - but again that's not what my reserch/goal is about.

Ultimately I will consider cost, who wouldn't. At this stage its about trying to select the best prop for the objectives as stated. Then if there are one or more offerings, that seem to be about equal, (no clear winner) I will use cost to make the decision.

4 minutes ago, Kyle Communications said:

hahahaha you should know my answer to your last part of your post....put on a Eprop and it will be better than your Fitti  😁

 

 

 

Juts wanted to give you an opening

1 hour ago, KRviator said:

Great video  - What's the repeated many times,  the right hand down in the foot well movement ?.