What is the weight of a medium bomber propeller blade

pirate_smee · Dec 5, 2020

Hello has anyone information how heavy propeller blades are for medium bombers as B-25, He-111?

Michael Hope · Dec 10, 2020

Do you mean the individual blade or the entire propeller assembly. The 23E50 propeller assembly, with aluminum 6359A-18 blades, weighs approximately 461 pounds, per FAA TCDS P-603. I have no idea on a He-111.

PFVA63 · Dec 10, 2020

Hi,
I don't have any information on German Propellers, but in the book "America's 100,000" by Francis Dean the author provides a lot of weight info on US WWII fighter planes. I tried to plot the data provided against propeller diameter and what I think the number of blades were for each different plane that data was provided for as shown in the plot below.

Unfortunately, I can't vouch that all the info that I entered is necessarily correct since the number of blades wasn't always listed in the book for each plane variant, so I tried my best to see if I could figure it out based on info on the internet (in particular there are two different points for 13ft diameter bladed props that vary a great deal in weight).

In addition, I think that the "Propeller Group" weights listed in the book might contain more than just the propeller itself (for instance it might also contain the weights of any hydraulic mechanisms etc, but I am not fully sure right now).

Anyway, hopefully this might help you at least make an estimate for the propeller that you are interested in,

Michael Hope · Dec 10, 2020

PFVA63 said:
Hi,
I don't have any information on German Propellers, but in the book "America's 100,000" by Francis Dean the author provides a lot of weight info on US WWII fighter planes. I tried to plot the data provided against propeller diameter and what I think the number of blades were for each different plane that data was provided for as shown in the plot below.

View attachment 604548 View attachment 604548

Unfortunately, I can't vouch that all the info that I entered is necessarily correct since the number of blades wasn't always listed in the book for each plane variant, so I tried my best to see if I could figure it out based on info on the internet (in particular there are two different points for 13ft diameter bladed props that vary a great deal in weight).

In addition, I think that the "Propeller Group" weights listed in the book might contain more than just the propeller itself (for instance it might also contain the weights of any hydraulic mechanisms etc, but I am not fully sure right now).

Anyway, hopefully this might help you at least make an estimate for the propeller that you are interested in,

You can get basic weights for propellers from the FAA TCDS for the each. https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/MainFrame?OpenFrameset
The differences in weight can be attributed to the blade width, i.e. tooth pick blades or paddle type blades, and then solid aluminum, H/S, or hollow steel blades, Curtis and others

pirate_smee · Dec 11, 2020

Thank you for the Information, I#m looking for the data of one propeller blade.
I'm interested in the accelleration at the engine if one Propeller blade was missing.

Michael Hope · Dec 11, 2020

pirate_smee said:
Thank you for the Information, I#m looking for the data of one propeller blade.
I'm interested in the accelleration at the engine if one Propeller blade was missing.

Do you mean if a blade broke off when running> The design theory on the blades have a pull of about 25 tons outward on the blade shank when rotating. You loose one and it can pull the engine out of the airframe, or break off the gear box on the front of the engine.
A single aluminum blade like the B-25 used is about 100 lbs. Sorry I do not have one handy to weight. By comparison, a 13 foot diameter Hamilton Standard blade as used on a ATR-42 weights about 52 pounds. When one did break off in 1990's, the one blade that broke off went through the cabin, just missing a person and the remaining three blades and hub, broke off the gear box and landed on a frozen lake.

pirate_smee · Dec 11, 2020

Michael Hope said:
Sorry I do not have one handy to weight.

Thank you that's perfect. The 100lbs is something I can work with.

MiTasol · Dec 29, 2020

Michael Hope said:
Do you mean if a blade broke off when running> The design theory on the blades have a pull of about 25 tons outward on the blade shank when rotating. You loose one and it can pull the engine out of the airframe, or break off the gear box on the front of the engine.
A single aluminum blade like the B-25 used is about 100 lbs. Sorry I do not have one handy to weight. By comparison, a 13 foot diameter Hamilton Standard blade as used on a ATR-42 weights about 52 pounds. When one did break off in 1990's, the one blade that broke off went through the cabin, just missing a person and the remaining three blades and hub, broke off the gear box and landed on a frozen lake.

I was visiting Helena Montana in 1967 when a guy raced into the FAA GADO and said everyone needed to race over to a particular hangar and see Jacqui Cochranes Piper (Navajo or Seneca or similar) aircraft because it had lost half a prop blade during take-off just after rotation. She feathered it and aborted. The engine and cowlings were only attached by the engine control cables and fuel etc hoses.

An AD came out soon after requiring removing certain decals from all props as the glue was causing corrosion leading to blade failure.

Michael Hope · Dec 30, 2020

MiTasol said:
I was visiting Helena Montana in 1967 when a guy raced into the FAA GADO and said everyone needed to race over to a particular hangar and see Jacqui Cochranes Piper (Navajo or Seneca or similar) aircraft because it had lost half a prop blade during take-off just after rotation. She feathered it and aborted. The engine and cowlings were only attached by the engine control cables and fuel etc hoses.

An AD came out soon after requiring removing certain decals from all props as the glue was causing corrosion leading to blade failure.

An AD was issued for Sensenich Brand propellers because they used water soluble decals on the aluminum fixed pitches, so this was not for a Navajo, nor a Seneca which came out about 1972, more likely a single engine Piper. I do not know of any other AD's for blade decals from the USA.
FAA AD 66-23-02 SENSENICH: Amdt. 39-289 Part 39 Federal Register September 22, 1966. Applies to All Fixed-Pitch Metal Propeller Models with Water-Soluble Mid-Blade Decals.

I can remember putting water soluble decals on propeller blades before this happened, which were then changed to adhesive stickers around this time.

MiTasol · Dec 30, 2020

Thanks Michael

It was definitely a Piper twin with VP props and the AD arriving soon after obviously made me mistakenly assume they were linked.

Also seeing as the AD was fortnight 23 of 1966 the incident itself must have been in 66. I must be getting

What is the weight of a medium bomber propeller blade

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