PDA

View Full Version : How vulnerable were propellers in real life ?



XyZspineZyX
08-04-2003, 02:19 AM
A disturbingly large portion of my flying time online is taken up watching cannon fire streaking past my window from 6 o'clock. The remainder, depressingly, is taken up by watching my ammunition sail harmlessly past my quarry's fuselage.

Now, a huge amount of explosives must cross the path of an aircraft's propeller everyday but to no effect it seems. I've never had my propeller shattered in FB so I guess it isn't modelled, but did it happen in real life combat ? How vulnerable was the propeller to enemy fire ?

Lixma,

Blitzpig.

XyZspineZyX
08-04-2003, 02:19 AM
A disturbingly large portion of my flying time online is taken up watching cannon fire streaking past my window from 6 o'clock. The remainder, depressingly, is taken up by watching my ammunition sail harmlessly past my quarry's fuselage.

Now, a huge amount of explosives must cross the path of an aircraft's propeller everyday but to no effect it seems. I've never had my propeller shattered in FB so I guess it isn't modelled, but did it happen in real life combat ? How vulnerable was the propeller to enemy fire ?

Lixma,

Blitzpig.

XyZspineZyX
08-04-2003, 02:36 AM
I don't know about wartime propellers, but modern small aircraft often have aluminium propellers and no more than an iron bar (one of those things you attach to the nosewheel and pull the aircraft around with) is sufficient to cut the end of the propeller and damage the engine.

We had one, who forgot to remove the bar, ended up with a cracked crankcase and a tip missing from one of the propellerblades, the bar though only got bent.

rgds

XyZspineZyX
08-04-2003, 04:12 AM
There was a very good scan from a book posted here by a nice gentlemen a few weeks ago showing US Navy aircraft combat losses by damage type. I wish I would have saved that, or even book marked it, it was very interesting. If I remember correctly prop damage was the least common damage (other than 'Other category') with a single digit percentage (3% maybe, sorry poor memory), while pilot death was one of the highest (46%?). Apparently the prop is not particularly vulnerable as compared to other critical 'systems'.

XyZspineZyX
08-04-2003, 04:17 AM
i would say they would be fairly, i mean its a huge spinning sometimes as big as 12ft accross fan. all it takes in one bullet and it could break a prop which would trash the engine

<center>I know my name is spelled wrong

XyZspineZyX
08-04-2003, 04:36 AM
read pilot accounts. props get holes all the time from gun fire and they return to base. there are much worse things to take fire on. like the pilot.

www.fighterjocks.net (http://www.fighterjocks.net) home of the 11 time Champions Team AFJ. 6 Years Flying http://www.world-data-systems.com/aerofiles/albums/userpics/p47-22.jpg

XyZspineZyX
08-04-2003, 05:37 AM
An MG round fired from hundreds of feet would most likely ricochet off a prop but a cannon round would probably do much more damage. Even in WW1, before the intermittent firing mechanism was adapted to be able to fire cowling guns between propellor blades, steel plates were placed on the wooden blades to stop bullets that didn't pass through the blades. And that was at point blank range.

m.olsztyn.pl/muzeum/wojskowe/il2.jpg
"Cowards die many times before their deaths;
The valiant never taste of death but once."

Message Edited on 08/04/0301:43AM by EvilBen

XyZspineZyX
08-04-2003, 06:02 AM
EvilBen wrote:
- An MG round fired from hundreds of feet would most
- likely ricochet off a prop but a cannon round would
- probably due much more damage. Even in WW1, before
- the intermittent firing mechanism was adapted to be
- able to fire cowling guns between propellor blades,
- steel plates were placed on the wooden blades to
- stop bullets that didn't pass through the blades.
- And that was at point blank range.



The metal plates had a "not so desirable" side-effect of occasionally ricchocheting bullets directly back at the pilot.


It seems likely that given the high velocity of a mg or cannon round it would often pass right through a prop without hitting it ata ll.

<center> http://groups.msn.com/_Secure/0SQDLAtUWiWZ3BKw19!aryp7v3C1h1DuNwpHOOuqhlraGSyMAY KiPEOZAA1OBgsLu*Sa0UQ2my0PiFyvNkJ5K7Clsoy7yNtEvOXY nHDuPNiotpZACY2oJxw/aircraftround.jpg </center>

XyZspineZyX
08-04-2003, 06:07 AM
Remember - most of a prop disk is empty space.

Hitting the prop disk would be (relativly) easy.
Hitting a blade is hard - for an individual bullet/shell.


Those WWI deflector plates were used before interupter gear was installed. They protected the prop against the plane's own bullets firing through the prop disk.
(IIRC, interpter gear was patented before WWI)



<div align="center">

http://www.robert-stuart.me.uk/il2/signature/paint_sig_003.jpg

I've given up correcting my own spelling
Unless I've corrected it here <MAP NAME="paint_sig_003"><AREA SHAPE="rect" COORDS="0,159,199,199" HREF="http://www.il2airracing.com" TARGET="_blank" alt="Air Racing" title="Air Racing"><AREA SHAPE="rect" COORDS="0,0,199,159" HREF="http://www.robert-stuart.me.uk/" title="Painter's home page" alt="Painter's home page"><AREA SHAPE="rect" COORDS="199,0,399,199" HREF="http://www.robert-stuart.me.uk/il2/index.html" TARGET="_blank" alt="Painter's IL2 Pages" title="Painter's IL2 Pages">
</MAP></div>

ShadowHawk__
08-04-2003, 08:17 AM
It's just as likely for a round to hit the blade of a prop as it is for you to hit your own prop if you didn't say have an intermittant firing mechanism. Think about it, it only makes sense.

-----------------------
http://www.geocities.com/tk_shadow_hawk/Signature.txt
-Death From Above

XyZspineZyX
08-04-2003, 08:33 AM
IAFS_Painter wrote:
- Remember - most of a prop disk is empty space

Cool could this be RBJ's new name then? PropDisk.

XyZspineZyX
08-04-2003, 08:48 AM
Taylortony wrote:
- IAFS_Painter wrote:
-- Remember - most of a prop disk is empty space
-
- Cool could this be RBJ's new name then? PropDisk.
-
-


When reading RJB's comments, read what he says in a literal sense.

He is often correct, he never attacks people, but ...
... how he says it winds people up, so they don't check what is being said.


[mods - don't let this thread become yet another flame session]

<div align="center">

http://www.robert-stuart.me.uk/il2/signature/paint_sig_003.jpg

I've given up correcting my own spelling
Unless I've corrected it here <MAP NAME="paint_sig_003"><AREA SHAPE="rect" COORDS="0,159,199,199" HREF="http://www.il2airracing.com" TARGET="_blank" alt="Air Racing" title="Air Racing"><AREA SHAPE="rect" COORDS="0,0,199,159" HREF="http://www.robert-stuart.me.uk/" title="Painter's home page" alt="Painter's home page"><AREA SHAPE="rect" COORDS="199,0,399,199" HREF="http://www.robert-stuart.me.uk/il2/index.html" TARGET="_blank" alt="Painter's IL2 Pages" title="Painter's IL2 Pages">
</MAP></div>

Message Edited on 08/04/0308:50AM by IAFS_Painter

XyZspineZyX
08-04-2003, 01:33 PM
in WW1, the French plane with the metal plates, were mounted on a plane that used metal props, when he crashed behind the lines and the Germens found his plane and tested the idea on there plane, the MG rounds ended up shattering the wooden props that they used

and that opened the door for A Foker and his model of the interuptor gear (which someone else had designed, but he got to work)

HARD_Sarge




Message Edited on 08/04/0312:34PM by HARD_Sarge

XyZspineZyX
08-04-2003, 01:43 PM
Even though props were hit many times in battle during WWII, the reports I've seen show that little damage was done due to the high speed of revolution somehow deflecting the bullets (don't ask me how, this is just what a Boeing engineer told me). They had more problems with props made of wood being mounted on high powered airplanes like the spitfire. These wooden props would come apart at high speed. Apparently though, this was corrected early on in the war.


http://www.theinformationminister.com/press.php?ID=612325917

XyZspineZyX
08-04-2003, 02:25 PM
Ah, I'm very happy you found my post interesting.. /i/smilies/16x16_smiley-happy.gif Well, it is fascinating data so simply go there to see it...

http://www3.sympatico.ca/sbmel/Damage_report.jpg



Alternatively, you can go there and see the whole message....

http://oldsite.simhq.com/simhq3/sims/boards/bbs/ultimatebb.php?ubb=get_topic;f=98;t=002238


From one nice gentleman to another, Salute!! /i/smilies/16x16_smiley-happy.gif

Stef51

XyZspineZyX
08-04-2003, 03:13 PM
Sorry - can't post an image but I have a good photo of an Bf109 (JG54- I think its a Gustav) with a very neat bullet hole through the prop blade. I think generaly a round would either penetrate the prop and pass straight through or ricochet harmlessly.
Prbably a different matter with the earlier wooden props ( a la BOB Spit Mk1 etc. ) when there was a real chance of a 'shatter'.
Am I right in suspecting that a more modern composite/carbon blade would be more at risk?

XyZspineZyX
08-04-2003, 04:32 PM
How vulnerable were propellers in real life?

Just think of how many propellers pilot trainees went through before they learned to fire in-between the rotating blades!!!!! Sheesh!!!!! In comparison, learning to fly the aircraft must have been a piece of cake.

Thank God that´s not modelled in the game. I find the prop moves so fast, I wouldn´t really be able to know if one of the blades was in the way as I pulled the trigger.

I figure start-up pilots were assigned to the two-bladed prop planes (50-50 chance of shooting "through" the spinning propeller) while the more experienced ones were told to fly in up to five-bladed-prop aircraft, where the probability of hitting the prop would rise to 5 to 1). That´s the definition of ACE, really, if you ask me.

Hey, they did have solutions to this, though... Some aircraft had their weapons moved onto the wings. No more propeller vulnerability. But then they came up with multiple engines, so the problem of placing weapong came up again...

Luckily, today, jet aircraft don´t have propellers, so that´s not an issue anymore.

Any more "technical" questions? I´ll be here all day to answer all of them.

Good luck with your shooting, men!

GreyBeast_P39

XyZspineZyX
08-04-2003, 09:45 PM
Very interesting... Do us a favor ,don't forget to show us the pic one day when you'll be able to, I'd like to see what it's like... /i/smilies/16x16_smiley-happy.gif

Stef

XyZspineZyX
08-04-2003, 10:01 PM
GreyBeast wrote:
- How vulnerable were propellers in real life?
-
- Just think of how many propellers pilot trainees
- went through before they learned to fire in-between
- the rotating blades!!!!! Sheesh!!!!! In comparison,
- learning to fly the aircraft must have been a piece
- of cake.
-
- Thank God that´s not modelled in the game. I find
- the prop moves so fast, I wouldn´t really be able to
- know if one of the blades was in the way as I pulled
- the trigger.
-
- I figure start-up pilots were assigned to the
- two-bladed prop planes (50-50 chance of shooting
- "through" the spinning propeller) while the more
- experienced ones were told to fly in up to
- five-bladed-prop aircraft, where the probability of
- hitting the prop would rise to 5 to 1). That´s the
- definition of ACE, really, if you ask me.
-
- Hey, they did have solutions to this, though... Some
- aircraft had their weapons moved onto the wings. No
- more propeller vulnerability. But then they came up
- with multiple engines, so the problem of placing
- weapong came up again...
-
- Luckily, today, jet aircraft don´t have propellers,
- so that´s not an issue anymore.
-
- Any more "technical" questions? I´ll be here all day
- to answer all of them.
-
- Good luck with your shooting, men!
-
- GreyBeast_P39


GB.....I...think you may not be aware of the fire-interrupter template and cam designed in WWI and first installed on the Eindecker...the pilots didn't "learn to fire between the blades"...I don't know how you arrived at that conclusion, or if you're joking, but there was no skill to be learned in the method of not hitting a prop blade. A mechanical device was used to make it impossible to fire when the blade was in line with the guns.

XyZspineZyX
08-04-2003, 10:20 PM
No, no! The mechanical device you talk about was not invented until 1954! In WW2 pilots used a stopwatch along with the RPM gauge. When they were in good position to fire, they timed when a prop. blade passed in front of the guns and based on the RPM reading multiplied by the number of blades in their prop, they would use the stopwatch to determine when it was safe to fire.

Novice pilots were often guilty of spray and pray, meaning that they pressed the trigger too long and could only pray they did not damage anything.

/i/smilies/16x16_smiley-wink.gif



Message Edited on 08/04/0304:23PM by KrasniyYastreb

XyZspineZyX
08-04-2003, 10:47 PM
I hink we have a conflict between historians and jokers here ...


... in case it's just ignorance ...

http://www.wwiaviation.com/early_dev.shtml




<div align="center">

http://www.robert-stuart.me.uk/il2/signature/paint_sig_003.jpg

I've given up correcting my own spelling
Unless I've corrected it here <MAP NAME="paint_sig_003"><AREA SHAPE="rect" COORDS="0,159,199,199" HREF="http://www.il2airracing.com" TARGET="_blank" alt="Air Racing" title="Air Racing"><AREA SHAPE="rect" COORDS="0,0,199,159" HREF="http://www.robert-stuart.me.uk/" title="Painter's home page" alt="Painter's home page"><AREA SHAPE="rect" COORDS="199,0,399,199" HREF="http://www.robert-stuart.me.uk/il2/index.html" TARGET="_blank" alt="Painter's IL2 Pages" title="Painter's IL2 Pages">
</MAP></div>

XyZspineZyX
08-04-2003, 10:59 PM
I have a photo of Spitfire Mk.V. hit by a ground fire directly in the propeller and it cut the end of one blade, the problem was not a damaged blade, but the hit itself caused a arbor damage which could jamm the engine.