Which Prop?

[John Waterson]

Here some results from our prop trials. Also take a look at John Gilpin's site: http://www.stolspeed.com

[Cloud Warrior]

Interesting reading.

Just for interest - Bolly now produce the Brolga blades here in Oz. There are still a lot of Airbornes flying around with the prop. Only problem is that it is just so ugly.................

[redrocket]

Hi guys
I have tried the same P-Prop , 34"pitch on 2 different trikes.

Trike 1 was an old 80's manufactured Cosmos 503SI motor with high aspect ratio wing that could lift heavy load at Middelburg / Witbank in a short take off run any time of the day. But cruise speed was slow compared with other trikes and the wing was a bitch out of hell in turbulance.

Trike 2 is a Windlass with an Aquilla 1 wing. It takes a lot more runway space to get off the ground and needs more juice to get up there. ( It does fly exactly as it is advertised, docile witout the bitchiness of the abovementioned wing.)

My point is that prop performance also goes hand in hand with wing type and speed!

I once had a Quicksilver, (ZU-BOW) now owned by Jana Meyer, Witbank which performed a lot better with a composite prop than a P-Prop, but the comp prop was very soft. The comp prop tips started cracking. When i scrutenized it under a magnifying glass it looked like carbon flaking.

Regards
redrocket

[pprop]

Ah hah!!! yep my favourite subject “Propeller bashing” Niccceeee!
Oh, WOW, Alanmack I am sooooo happy for you that you have found an excellent propeller, I wish you only great and safe flying always! From Bets (my wife), Julius Motele and myself.

Now, gentleman of the forum…. where to begin with grateful acknowledgments?. (Add enthusiastic applause here)
So decent of you to have invited me to this forum beforehand. A hearty thank you! (You are most welcome)
So nice of you to have informed me of the relevant experiments to be done beforehand. (No problem)
So nice of you to have asked me to assist in the experiment, or to help to set the facts straight. (It’s a pleasure.)
So nice of you to have introduced me to the learned gentlemen ( 35000 hrs – WOW!!) assisting you in this meticulous experiment. ( What are friends for?)
Did I just hear someone whisper “sarcasm is angers ugly cousin”? Gentleman, you are soooooo right!!
I really, really appreciate a good old blindsided crippling stiletto attack in front of an observant audience, especially more so when ALL of the relevant FACTS - maybe on purpose, maybe not, who knows? – are hidden from view.
I’ll have to explore these scribbling in the greatest of details so that the highly qualified gentlemen perusing these halls of truth (and blatant hidden lies) shall come to a reasonable, fruitful and above all FACTUALL ( Factual = based on true facts backed by the uttermost important relevant paperwork and the relevant dates, for the lesser informed scholars…..) conclusion.

Let me pull out and dust off, my 30 year file containing a detailed record on
1) Every single propeller, since 1983, ever designed theoretically and
2) Manufactured practically by P PROP.
Let me pull out my trusty old SERVICE, REPAIR and MAJOR OVERHAUL file (which, by the way, contains my private notes, on the degree of damage of a particular propeller.)
OOOOkaaaaay. I think I have a couple of nukes here on my table…. Laid out in order.
Ready for a slaughter guys? Hah, I am, for sure!!

History
Original design =1990. The airfoil was based, at the time, on an “Aquilla” airfoil, co – ordinates for the abovementioned airfoil was plotted by hand. It is thick, it has a flat bottom, and is easy to build.. This airfoil was then used by P PROP, GEO KILLEY, RITZ propellers and just about
The very first propeller for this gentleman was:-
N2115 FE C2 G4 Manufactured 3 May 2002. Ordered by Manfred Springer, Aviate Products, for a Raptor 582 plus 3,47 Gearbox.
No stainless steel protection on new propeller.
One year and 11 months later:-
Damaged some weeks before 23rd of March 2004.
Time flown = 85 hours
Cause of damage: - Appparent failure of the urethane leading edge protection, in-flight, due to the complete weakening effect of multiple, severe, strikes to the urethane protection resulting in a loss of the integrity of the product.
(Why use a condom twice? It’s not recommended at all and is prone to catastrophic failure at the most inconvenient of times)
The pilot admitted to having landed, taxied long distances and had taken off several times at Mkuzi as well as at different locations generally around and near the vicinity of Mkuzi on any piece or part of terra firma which resembled a runway.
NOTE:- A donkey resembles a Giraffe doesn’t it? I mean they both have a head don’t they? A tail, a back, hair and four legs, don’t they?
This comments is jotted down in pen, in the repair and service journal, whilst in actuall conversation with the pilot in command on the 23rd of March 2004.
At visual inspection I found several impact damaged areas indicative of stones as well as severe abrasion indicative of sandblasting.
NOTE This propeller was NEVER brought in for inspection in 2 years – (AT LEAST ONCE A YEAR my little dearies!!!)
The result was that we did major, major repairs and a complete overhaul and coated the propeller in a glossy RED to cover up the dastardly, ugly looks / visual impression of the repairs from the 23rd of March 2004.
Between April and the 3rd of August 2004 the pilot had another accident serious enough to turn 70% of the 72” propeller into slivers of wood and toothpicks.
So that was the final gruesome end of N2115 FE C2 G4
The 2nd propeller for this gentleman was:-
The History of N2399 FE C2 G4 S4 born AUGUST 2004
On the 3rd of August 2004 the pilot ordered a new propeller as well as 4 sections of 75mm x 45mm x 0.5mm stainless steel once again to try and combat the damage the propeller recieved by landing and taking off in areas deemed unsuitable for runways (Told to us with a hearty laugh and a close, secretive, buddy to buddy, whispering in the ear, slightly forward leaning type of stance – get the picture?)
A note was made that the pilot recieved the propeller at dealers price. (We had to listen to an seemingly endles tearful story relating to how much the accident cost in time wasted, the cost of major repair work to the RAPTOR etc, etc. We felt sorry for the poor guy, understand? Such misfortune in such a small time,
“Agge shame dominee!!!.... Kan dit regtig ooit waar wees?!.... (pregnant pouse) dat soveel misrabele moeilikheid een mensie kan tref?” (To be read out loud in a Mrs Doubtfire Falsetto tone with sorrow etched on the face of the little old lady as she looks skyward for help from above.)
DAMAGE HISTORY of N2399 FE C2 G4 S4 – ( BRACE YOURSELF DEAR READER!!!)

This propeller was in 4 serious accidents.
1) The 28 / 3 / 2006 – Damage to 30% of each blade. Major overhaul. AND – WAIT FOR IT – ALL 8 SECTIONS OF STAINLESS STEEL HAD TO BE REMOVED AND REPLACED BY 8 NEW SECTIONS!! Cost = R1100.00

2) The 20 / 3 / 2007 - Severe damage to 60% of each blade. Recomended to scrap propeller. Major, major, overhaul AND – WAIT FOR IT – ALL 8 SECTIONS OF STAINLESS STEEL HAD TO BE REMOVED AND REPLACED BY 8 NEW SECTIONS!! Custom painted RED to hide repairs. Cost = R2800.00


3) The 10 / 6 / 2007 – Slight damage to 20% of each blade. Tips damaged. Replaced 2 sections stainless steel. Recomended to scrap propeller because of repaired damage, on top of repaired damage on top of repaired damage. Cost = FREE of CHARGE. Custom painted to ORANGE.

4) The 01 / 10 / 2007 – Severe damage to tips. I actually refused to repair the propeller verbally. Witnesses to this event = Bets de Necker (my wife), and Julius Motele ( Trusted, meticulous intelligent worker of 12 loyal years with more general propeller service and repair knowledge, balancing methods, and painting work than ANY, ANY OF YOU GUYS READING THIS. We relented at the sad face shown and di major work – once again. Costs = R1800.00 Custom painted to ORANGE.
Lets tally up to see how even the playing ground is shall we?
On the one side:
N 2399 – originally designed 1988, built 2004, Aquilla airfoil, 4 x overhauls / services / repairs - made by hand – not CNC to an accuracy of 1mm or less .of which 2 of the overhauls where of such a serious nature that we recomended that the propeller should be scrapped. 75mm x 45mm x 0.5mm stainless steel wrapped over the leading edge.
On the other side:
A brand new Aeroprop, designed probably round 2000, built probably 2008 or later, Clark y or 99% similar airfoil, nil overhauls / services / repairs. Molds made by CNC probably to a tolerance of 0,3mm or less. A section of stainless??? Steel 290mm long x 25mm wide x 0.5mm thick FLUSH fitted to the leading edge. Tip vortex fins to combat spillage of airflow from the airfoilt to
P PROP Aeroprop
Designed 1988 Designed 2000?
Handmade 2004 CNC made 2008?
Aquilla airfoil circa 1910 Clark y SM or 99% similar 1927
4 x damaged 0 x damaged
Length = 72” Length = unknown
Pitch = 50” Pitch unknown


Books to read please
1) The idiots guide to static thrust. Author Proff. B.U. Llshit.
2) Static thrust for idiots. Author Dr. M.E. Anszero
3) Static thrust – The Fairy Tale.
4) The static thrust manual for Dummies.
3) The Famous Idiots list of Static Thrust supporters.
5) Static thrust – Methods of analysis for idiots.




To: - CLOUD WARRIOR: -

NO, no, no Sir – not legal and very foolish to fit a propeller from one aircraft to the other. (Trike to Cubby I presume?) Please don’t! Send me the number of the propeller and I shall rather look for a buyer for you.Hows that?



To:- SZ-NEL.
Should you buy the ORANGE prop discussed above please, please, I beg you, bring it here and we shall strip the paint layer by layer AND expose the repairs layer by layer so that you can see for yourself (and anybody else that cares to accompany SZ –NEL to 387 Long ave, Ferndale, Randburg, tel number 011 793 5235) the damage that this particular model endured.
FREE OF CHARGE – VERNIET – MAHALA !!
After this sordid affair I shall explain to you the MASSIVE changes gone through P PROP the last 2 years with particular emphasis on the technological advances made locally - out of a GARAGE - in the last 3 months. -

To: - RUDIX
Yep I have seen this myself and have refused to repair these type of splits. I would be very interested to compare notes with you here, in the open, and invite anybody else that have split blades in their possesion to show their evidence of composite propellers that have split open without impact damage present..
I have 1 x set of 3 new AEROPROP blades that has the slightest (probably 5 to 8 mm x 4 mm deep) impact damage to the steel leading edges. 5 hours service. Unrepairable.
I have a new WARP DRIVE blade here split on the leading edge. 0 hours
I have 3 WARP DRIVE BLADES here split and cracked open where the steel insert joins the hub. 200hours.
I have a WOODCOMP blade here that was broken off by pushing on the blade by a family member. The inside looks attrocious. Hours unknown.
I have 1 x Ritz propeller here that threw a blade on full throttle. Instructor at the time = Philip van Niekerk (Bapsfontein, Aircraft = Challenger, Engine = 582 + belt drive. Place – farm near Venterstad. 15 minutes.
I have a GSC 3 blade stub here. It threw a blade on a farm near Steynsburg in the Free State. Pilot was an SAA 747 Captain. Aircraft = Beaver. The Beaver was 3 meters above the runway, when the blade said “adios amigo, adios my friend....” right after rotating. The engine promptly destroyed the engine mountings, then the keel, the fuselage and wing integrity and crashed on the farm runway. The pilot escaped with minor injuries



To:- German, Thank you!



To:- Boet,

Dankie twice, Boet - hier is drukkie en n soentjie. Yes, the P PROP integrity in 30 years is 100%.



To:- Tailspin
Dear Tailspin

For the life of me I dont know who you are BUT,,
If I ever gave a lecture on propellers, and you where present in the audience, I shall rather have you sitting in a chair, here beside me, on stage, than having you in the audience throwing a couple of knee buckling questions in my direction.
You have my grudging respect, Sir.!!
The reason? The 4 questions asked by yourself here on this forum is of such a valid nature that I must regard you as:-
1) Someone that has higher aeronatical qualifications than the ordinary JOE SHMO microlight pilot / instructor / microlight school owner with
2) The obvious experience in having compared pitch to pitch –(I doubt if anybody in this country – except for DE NEL AEROSPACE, IST, BOET and OUPA G – has this practical experience) and has
3) extensive knowledge of the effects longer and shorter blades have on the parameters of given engine power output converted to aerodynamic straight line thrust
4) and has theoretical and practical experience on the calculus necessary to find the correct blade widths for a specific propeller design and a specific aircraft engine / gearbox combination
So I would appreciate it if you would mind sharing your knowledge and experience since GEO KILLEY left SA I haven’t had anybody to discuss the questions you have asked above.
I applaud your questions – cold, calculated and valid straight out of a 4th year major in an Aeronauticall degree exam paper.
I would really like to talk to you....

[Boet]

Jaaa Swaer , unfortunately much easier to BANG something than to make it. It seems to me that the P-Prop used has definately seen some better days. I think it is time to replace it with a new one, and then you can re-test the whole shebang. Pieter is one of our most valuable members, and I detest people saying anything wrong about him, for he is also a good friend af many years. Ek DINK die Oom is bietjie die bliksem in vir jou.

[Boet]

Herewith some pics of one of those wonderfull compsite products some people so love to hang onto their engines. ( Excuse me for the fact that I ever since have cast a rather beady eye on the type. ) Oom Piet can correct me, if I am wrong, but I think this is the one broken off by yhe family member. On the same vein, I would like to add: Dit sal maar kak om n P-Prop so af te breek!











You can always trust a tree!!

[German]

Mooi gese Piet.
Daai Pprop wat jy en Niel uitgewerk het, en jy toe gebou het is 100% -take off and cruise!

[Big-D]

Oom Piet You are a legend

Thanks for your input, I loved reading it It put's things in a different perspective


D

[Duck Rogers]

Jislaaik!!!!!! Ek skiem Pieter is de moer in

[alanmack]

I would like to set the record straight on my views on Pieter de Necker, his family and staff and any misperception that may be drawn from comments on this forum. I did not and have never spoken ill of Pieter. I respect Pieter as a person and his workmanship that has stood the test of time. In fact, in the 2009 Winter Edition of Microflight Africa I saluted both Hennie Malan and Pieter de Necker whose passion and commitment to servicing our sport is nothing short of legend. Notwithstanding the above personal attack by Pieter upon my integrity I remain of the opinion that a man should not be judged by what I have taken to be an emotional outburst.

On the question of his props, those that know me know that I have, for years, been a loyal supporter of his prop and have defended my preference for the p-prop whose badge has pride of place on my flight suit. Yes, as I stated, I had to eat my words. I had to do this as I had defended the p-prop and by belief in it even after the results, as shared, were obtained.

I find the fact that Pieter keeps a secret note book on anything that may or may not have been said to him very unfortunate. I would hope that in the future his clients will request a copy of this service record and that they will take note of the manner in which it is written. His comments surrounding the peeling of the leading edge after take off at Mkuze, the reference to donkies and giraffes, the multiple take offs, condoms and more have left me no option but to respond. There were no multiple take offs and the scenario as painted is nothing short of being a sad emotional outburst. A group of us had flown to a Game Lodge close to the Josini Dam from Durban. We stopped on our return at Mkuze to refuel. After take off the leading edge on my prop peeled away and I returned to Mkuze. Paul Lintott lent me a prop and I continued on my flight back to Durban. Donald Hicks and Paul may be asked for their opinions on this matter. In any event I was always very happy with this prop and with the repairs to it. Yes, the dramatisation of the prop being turned into “toothpicks” is probably quite accurate. Many know that my call sign “Nemo” is derived from my trike having been washed out to sea whilst parked on the beach. This, of course, is another story but yes the prop was destroyed and I replaced it with a P Prop without any hesitation whatsoever. Pieter’s account of my “Nemo” incident is also unfortunate and the fact that he felt that he had to be subjected to it, is sad, to say the least. The replacement/repair after this event did take many months and it cost a lot, given that not much remained as usable parts. Yes, I had the new prop fitted with stainless steel protective strips. The inference that I may, on a regular basis make use of landing strips unsuitable for being runways is, again, regrettable. I can but say that those of you that know me know that I fly the Wild Coast and that I have shared the privilege of doing so with many. Our annual Wild Coast fly-away now attracts over 40 pilots and over the years many have enjoyed staying at my cottage on the Wild Coast that hosts this annual event. All that fly with us know that I do not take chances by operating in unsafe conditions. In fact, I believe that flying along the coastline offers more safe landing opportunities than inland flight.

As for the 4 serious accidents on the second p prop and the account that follows, again, this is presented in a manner that is unfortunate. Probably what he details to be the least serious I would have said was the most serious (engine out after full engine overhaul before it was due but as a precaution because I was intending to do a lot of flying over that Xmas period on the Wild Coast) and what he suggests was a serious accident was in fact the peeling of the fibre glass covering over the prop, whilst taxiing, caused by sand in the air. The inference may be gleaned that I coerced him into repairing the prop. I can but say that if ever he feels a prop is unsafe that he needs to use his better judgement on props gained by years of experience and to not repair a prop for a pilot to fly when, as he now infers, could have lead to the pilot flying in unsafe circumstances.

If you read the above comments you may be inclined to suspect that I have not been truthful. Unfortunately I must address this matter on this forum and will leave you to decide. How did this whole saga arise? At the outset I said I would leave the names of those involved out so as to focus on the facts. After the above attempt to discredit my integrity a crisp review is called for.

Jenya Zozulya flew my trike at Petit and told me that he felt that the prop was not producing optimal thrust and that he recommended that I not fly it without further assessment. I also said that seasoned pilots refused to believe that my prop could possibly be defective. I took Jenya’s advise and did not try and have the prop’s performance not assessed. I truly believed that the prop was fine and so did Andy Kasperson believe this to be the case. The static tests were performed in the presence of Mervyn Reynolds, Hans Schouten, Jenya Zozulya and others. If my estimate of only the above named pilots is not 35,000 hours I would be surprised.

Again I state that I said, very clearly, that I was fishing for more test results and at no stage did I attempt to cast doubt on the integrity of Pieter, his wife and staff. I take note that an open invitation was not offered to witness the tests conducted with a CAA certified scale. I note that Pieter’s response appears to attack my integrity but do believe that if you seek an answer to this matter that you ask someone that knows me for an opinion. Finally there remains the purpose of the whole matter above.

Do you have any test results?

In an attempt to rectify the above, if requested, I will, during the Starters Masters Competition from 5 - 7 February 2010, at Petit, repeat the above tests with as many props as are available. Should you wish your prop to be included please respond with the offer on this forum and with a suggested time for the above experiment. If you fear being subjected to a personal attack by the prop’s manufacturer please eMail me your request to nemo@webo.co.za and we will test your prop without reference to your name and I promise that I do not keep records for later emotional embellishment.

Should the above retests be requested I will publish a factual account of the the results in the next Microflight Africa magazine. I promise that the account will be factual and that I will not try and “slaughter” the integrity of anyone by reference to private notes or any other means.

Fly safe
Alan Mackenzie
Editor: Microflight Africa
Aka alanmack and nemo in the microlight fraternity.

[Cloud Warrior]

But... but.... the Duck said it would fit a Cubby?

Anyway too late she cried - the prop has had a new owner for some time now.

That rant from Pieter was a bit uncalled for I think. There was nothing in there disproving what had been said previously. Only a long very personal attack against alanmack whom I thought had been very complimentary about Pieter's work.

I would have thought that a well reasoned, counter argument showing the advantages of a two bladed wooden prop over the three (or more) bladed plastic props would have been more effective to dispel people's perceptions.

But then again maybe there isn't one?

Kind of happy I am with Bolly now.

[Hazzard]

OH DEAR!!!, what seems to have started out as a simple question on propeller performance has resulted in people bashing, which I am sure was not the plan at the start of the thread.
My experience: I replaced my wooden two bladed propeller with an Aero Prop when I still had my Raptor trike some years ago. The experience was that the Aero Prop performed better and was smoother. The two bladed propeller now rests against my ceiling on a fan shaft. Perfectly balanced and performs wonderfully as a ceiling fan. Looks good too.
Pieter, wind your neck in. The questions are of interest to many and not a personal attack on you, or your company. For as long as there have been alternatives and choices there have been different opinions. I have friends who fly aircraft with both two and three bladed propellers. Each has their own reasons for flying what they fly. I asked a mate of mine who runs a school what propellers he has on the school planes, and why. Wooden propellers he wants nothing of, (too much maintenance, keep level to maintain balance etc), nor does he want Aero Props for that matter as they are too easily broken. He has Warp Drive as he maintains these are the strongest. Nowhere does he talk of thrust, noise or how smooth.
P Prop bashing is not for me, but the subject of propeller comparative performance has always interested me. Go for the test Alan, raise the challenge and please publish your findings. Pieter, enjoy the competition, you, and your business for that matter will be the better for it..
As for the long winded diatribe; it is my opinion there is no correct answer, only the right to ask questions, have preferences and incite discussion. Not even in the contraversal arena of Microlighters, do I believe that character assassinations are solicited. Heated debate, yes, assassinations, NO.

[Donald Hicks]

Sorry guys, felt the need, having re-read the thread, to say something else.

Tailspin, I fully agree with you in one respect, (not only one, but this one especially), wooden 2 blade props are the prettiest, no question. I in fact have two spare wooden props, neither of which is for sale. Both hold pride of place in my pub, both still work, (as mentioned….. ceiling fans).

I believe there is little within the entire thread that refutes the findings. Pieter, if you want to have your day in the sun, you must respond correctly.

I happily acknowledge the following

• The different properties, fine for power versus course for cruise
• Gearbox ratios
• Propeller length
• Efficiency

Folks,Pieter needs to address the issue from a position of knowledge and not emotion. From what I could make out, Alan was quite disappointed by the fact the he was worse off. I wager he would not have bet against the P Prop.
Come on Pieter, get off your soap-box, do some homework, dust off cupboard full of “proof” and confirm your lofty position. Nobody questions your experience, go to PETIT and “strut your stuff”.

Or just admit that there is some pretty good kit out there that looks “OK” but can more than deliver the goods!!!!

I remember when Irish Linen was the material you covered your plane with and all pilots were classified on the same grade as train drivers. When children listened to their parents, when caning was allowed and when propellers were made of wood!

[grostek]

I have re-read the whole thread twice now and will say the following.

To Alanmack
Comparing an old beat up prop to a new plastic fantastic is not a fair comparison
(Rather like doing a performance test with a 68 Corolla against a 2004 Lotus Elise or whatever)

By all means do your fly-off against other props but don’t just measure thrust, measure Total Performance.
Dist to unstuck point, Unstick speed, Dist to clear 50 ft obstacle, Rate of climb, cruise speed On various headings to cancel out the effects of wind , landing speed and distance to full stop over 50 ft obstacle. Fuel used. Use calibrated instruments to measure all this.Any other relevant information
Use same pilot. Use same aircraft/Motor/Gearbox combo.
Correct the data for differing Barometric pressures and temperature at different times.

Price might also be mentioned.

Using opinions by persons of high experience is not valid data, because it is subjective.
Whereas hard cold data from calibrated instruments is useable data and can be compared to other data collected and recorded in the same manner and method.
Opinions can not be compared, even if the offerees of the opinions have 35000 combined hours. Why? because opinions can not be measured.

Doing the fly-off in the above format will give the comparison credibility and might then be of some use to the layman and others.

To Pieter de Necker
Your product has a very good reputation and has many hundreds of satisfied customers so it is with reluctance that I say the following.
In business, anything said to the business owner or representative, in confidence, should remain confidential.
I fear by dragging your “private notes” into the discussion with the accompanying comments you might have done your business harm in the long term.

I wish you luck with your business and know that your excellent products will and do speak more positively than this thread.

Kind regards to you both.

Gunter Rostek

[Tumbleweed]

There are some of us who just trust the integrity of the aircraft designer and accept that they have done sufficient comparisons i.e. the Savanna. I'm sure he did'nt use pre-repaired second hand props in his quest for the perfect prop for his plane.

That said, it's unfair to challenge someone who makes comparisons, albiet not in a sterile environment. But at least someone has the balls, in a practicle way, amongst peers, to establish any differences.

Maybe the right way to go about it is to have the suppliers provide the reccommended new prop for each test. Attached then, a brief pitch like; custom made, repairable, e.t.c.

Oh, maybe include then, the best prop to survive general wear and tear from beach / outlandings.


I would have thought, especially in a confined marke, that repeat business is essentual.