Nigrowsky rotors

JETLAG03

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Morning folks.

I am now the proud owner of a Deluc Gyrocopter kit fitted with a Negrowsky (negrowski) rotors and a BMW K1200RS engine. Just at the final part of my Gyrocopter (autogire) training here in France and soon hoping to have the beast ready for the first run up later this year. I hope to replace all the nuts and bolts with new aircraft standard fixings, and replace the bearings in the head etc. Not sure all this is absolutely needs to be done, but, it's a question of personal confidence, changing them all will force me to check everything as I go. Also, I am a little mechanically minded so a deeper understanding of all the parts can only help.

Sizes etc should not cause too many issues, measuring the existing fixings and confirming the holes sizes hopefully should lead me along the right path. Are all aircraft standard fixings imperial sizes ??

The torque settings for the fixings I am not sure of. There are some big meaty bolts and I am guessing they will need a fair amount of torque, example the head and rotor mounting bolts.

Cadmium plated or stainless steel bolts, which are the better and why, I rather like the "looks" of the stainless steel, but, as my wife tells me when I'm looking woefully in the mirror "looks are not everything"

I read or heard somewhere a comment regarding the rotors and their cleaning, mine are resin, that one should only clean then with water and a gentle soap and never add a polish as this will make the rotors "too slippy" in the air and reduce their lift. Confused, I thought that making the rotors more slippy would reduce their drag and therefore improve their lift, am I missing something.

I will be posting lots of questions, some will be seen by some as silly or daft probably, but if i don't know or understand I would rather ask and look foolish than not ask and be foolish.

Looking forward to your learned replies.

Merci et Thank you

Phil
 
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XXavier

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Morning folks.

I am now the proud owner of a Deluc Gyrocopter kit fitted with a Negrowsky (negrowski) rotors and a BMW K1200RS engine.

(...)

I read or heard somewhere a comment regarding the rotors and their cleaning, mine are resin, that one should only clean then with water and a gentle soap and never add a polish as this will make the rotors "too slippy" in the air and reduce their lift. Confused, I thought that making the rotors more slippy would reduce their drag and therefore improve their lift, am I missing something.

(...)

Here you have some research on blade contamination...

 

AirCommandPilot

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Cadmium plated or stainless steel bolts, which are the better and why,

Cost is one factor, stainless fasteners are quite more expensive. Weight is another issue. Stainless weighs more. Also, there could be some galvanic corrosion between the stainless and aluminum.
 

Mike G

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Phil
Deluc & Negrowsky are French, I suspect the fasteners will be metric. Double check before buying any imperial nuts and bolts.
 

MilesW

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Cost is one factor, stainless fasteners are quite more expensive. Weight is another issue. Stainless weighs more. Also, there could be some galvanic corrosion between the stainless and aluminum.

Across the range of typical AN size fasteners in a gyro, the total weight difference would be insignificant. Maybe a pound tops.

Galvanic corrosion is a real concern though.
 

GyroCFI

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Back when I was training and had Skywheels rotor blades, I would wipe them off with Lemon Pledge which got the bugs off and left them a little bit "slippy" as you said. I never had a problem with losing lift and in fact did notice better performance once the blades were clear of bugs and had the lemon pledge wipe.
 

PW_Plack

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I read or heard somewhere...never add a polish as this will make the rotors "too slippy" in the air and reduce their lift.

I believe this concern is unjustified. My only concern would be to avoid cleaners or polishes which might attack the integrity of the resin over time.

I fly with Sport Rotors, which have a hard, smooth, urethane-epoxy finish. I still clean them with silicone wax, in the hopes they will accumulate less insect remains. I'm not sure that works, but it certainly makes them easier to clean after landing. I have confirmed through personal observation that splattered insects on my rotor can degrade performance.
 

Smack

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Cad-plated steel is stronger than (most) stainless or aluminum hardware size-for-size.
Brian
 

WaspAir

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Removing surface contamination and polishing will not result in loss of lift, so long as you are not building up enough wax to change the shape or make it irregular (and that's pretty difficult to do with something like liquid Lemon Pledge).

In my personal experience, cleaning and polishing the leading edge of the blades to remove debris such as dead insects could make at least a 1/2" reduction in the manifold pressure required to hold a hover in a Robinson R-22.

Likewise, as a sailplane (glider) pilot, we are notorious for wanting the smoothest, most mirror-like surface on our leading edges, and never, ever encounter any problem with being too "slippy".
 
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EI-GYRO

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I read or heard somewhere a comment regarding the rotors and their cleaning, mine are resin, that one should only clean then with water and a gentle soap and never add a polish as this will make the rotors "too slippy" in the air and reduce their lift. Confused, I thought that making the rotors more slippy would reduce their drag and therefore improve their lift, am I missing something.
This one comes up from time to time.
Cleaning, particularly the leading edge, is good, and will improve performance. Even very small amounts of bug guts have an effect, although you might not notice it on a powerful machine.

Polishing is a different matter. Some blades are supposed to be polished, and some not. The issue appears to revolve around blade pitch/profile and boundary layer considerations.
My extruded Rotor Hawks, for instance, operate best unpolished, and need to be roughed up a little periodically for best performance.
I think Dragon Wings need to be polished, or at least those I have seen appear to be polished.
Composites I know nothing about.

I suggest you read up on boundary layer theory on wings.
Otherwise, follow the manufacturer's guidance.
 

Acamacho

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Nunca monte tornillos de acero inoxidable en lugares importantes y estresantes.
 

First pilot

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Stainlesws bolts are not reliable enough for aviation use. Aircraft grade bolts have the correct proportions of toughness , hardness and flexability . Besides being Cad plated to resist corrosion of other metals. Thats what I learned from a Metal specialist.
 

Sanko26

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Stainless steel bolts are not aircraft grade. Don't use them. Use galvanized 8.8 bolts. I have no gyro,but I'm aircraft technician.
 

500e

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Presume you mean Cadmium plated bolts not Galvanised
 

Sanko26

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Presume you mean Cadmium plated bolts not Galvanised
No matter that the bolts are cadmium plated or galvanized. Both of them are to prevent corrosion. The number is the key. 8.8 shows U the tensile and yield strenght. 5.6 is very weak, 10.9 or more are too rigid,the 8.8 is commonly used in UL section. The process of corrosion prevent is not effect on the strenght of bolt.
 

500e

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What about size tolerance
 

hismiths

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The best bug-off cleaner out there? Dampened Bounce dryer sheets. Learned from Harley dudes, and reinforced @ OSH. Used on all my airplanes for years, with no adverse effects ... except to the bugs, pollen, dnd dust.
 

Vance

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No matter that the bolts are cadmium plated or galvanized. Both of them are to prevent corrosion. The number is the key. 8.8 shows U the tensile and yield strenght. 5.6 is very weak, 10.9 or more are too rigid,the 8.8 is commonly used in UL section. The process of corrosion prevent is not effect on the strenght of bolt.
I have never seen a galvanized aircraft nut or bolt.

With galvanizing it is very difficult to control the size and size is an important part of aviation hardware.

In my opinion how the fastener is protected from corrosion is very important.

In my opinion hardware that is corroded needs to be replaced because it affects the strength of the fastener.

Many people in the USA use AN (Army-Navy) aviation hardware with very specific specifications.

AN and metric hardware in not interchangeable.

AN bolts may have a specific size tolerance and I feel it is important to use the correct hardware for the application.

Hopefully the designer will have selected the correct hardware and in my opinion it is important to follow that recommendation.

Some manufacturers will use a fastener specifically made for that application. I feel it is important to use the factory hardware in these situations.

I feel it is important to use the correct torque as specified by the designer. Tighter is not always better.
 
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