Sparrowhawk rotorhead

Gyro Gerry

SparrowHawk 1
Joined
Aug 24, 2005
Messages
22
Location
Belleville, Illinois
Aircraft
SparrowHawk
Total Flight Time
25,000 hrs. fixed-wing, 300 hrs. gyroplane
The slider on my SparrowHawk rotor head has a metal plate on each side that keeps the slider pin centered and one of them broke. Does anyone know if these metal plates are spring steel or just aircraft steel that I can buy at Wick's aircraft supply. IMG_6210.JPGIMG_6211.JPGIMG_6212.JPGIMG_6213.JPG
 
Any steel with carbon content of 0.3% or above that can be hardened will work fine.

“Aircraft” steel, 4130 has 0.3% carbon content.

Heat cherry red, quench in water and draw until a polished area turns to a straw color.
 
It seems you were very lucky that the pivot did not come out
My question would be rather: "Why and how the elastic limit is exceeded on this plate?"
 
Last edited:
Chuck
What do you mean by"draw"?

JC
I suppose it was a fatigue failure rather than a simple ultimate tensile strength failure. Probably due to a nick or scratch that was a stress raiser (amorce de rupture ??) and/or incorrect or lack of heat treatment.
he was also lucky the broken part didn't go through the prop.

Gerry
You could try some of your town's washers 😂 Sorry couldn't resist it.

MikeG

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From the photos, it appears that it cracked off right at one of the holes where the bolts go through that plate...
 
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I replaced both slider pin centering spring plates that I made from a sheet of 4130 Chromoly from Wicks aircraft supply. I had them heat treated and tempered to a hardness range of 34 to 38. $11.00 for the sheet of 4130 and $109.00 to have them heat treated. I flew yesterday and they are doing what they are supposed to do. I want to share this with all and thanks for replying and pointing me in the right direction. I hope this helps the next guy in need of replacement parts.
 

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Looks like some good, thoughtful work Gerry. Thank you for sharing the fun.
 
what type of steel rod is the slider made from and the hardness.what type bushing for the slider
 
Hey Gerry, any pics of your Rotor tach sensor installation ?
 
Hi Chris. I have a couple of pics from when I built it 12 years ago and they are posted on my builders website called expercraft. There is a link to this on our club website. St. Louis Rotorcraft Club PRA Chapter 35. I can take some pics of some close ups if you need them. I screwed and glued the sensor to the bracket and attached it to the pre rotator housing and used polyurethane glue as you can see in the pics. Look under Builders's Construction Logs and Gerry Loeser's Builders log for a Sparrowhawk gyroplane on our club website for my entire builders log. Gerry
 
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Rotor Tach bracket for SparrowHawk
 

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Thanks, our manual shows it on top ? Was this your own idea ?
 
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