Hurricane Mk 1 CG Positions

[dreameruk]

Hi all new to the forum, as the title says im after the forward and after limits for the hurricane mk1. have googled but with no luck, that's when ii found this forum. would anyone know please or able to point me to where i can find ? thank you.

 

[Crimea_River]

Welcome board. We have a selection of Hurricane manuals here: Hawker Hurricane pilot manual. However, a quick scan through my copies did not reveal the info you are seeking. A weight and balance table is what I was looking for, and could not find, but the info may be buried elsewhere.

 

[dreameruk]

if they are the three manuals from this forum i have already looked lol, thank you though and thanks for the welcome.

 

[pbehn]

if they are the three manuals from this forum i have already looked lol, thank you though and thanks for the welcome.

It is briefly discussed here Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)
Post no 2510

Adding armour plate to the Hurricane moved the CoG rearwards, fitting the Variable pitch prop moved it forward again.

 

[MIflyer]

The Hurricane II maintenance manual says 60.4 inches aft of the datum point is aft CG limit and 56.0 inches aft of the datum point is the forward CG limit. The Datum point is aft of the prop under the middle of the exhausts.

I can scan the chart and post it if anyone wants it.

 

[dreameruk]

thanks guys, will give it a try.

 

[Crimea_River]

The Mk I will have different limits than the II owing to the shorter nose.

 

[pbehn]

This has some info.

https://assets.publishing.service.gov.uk/media/5f881a01e90e07415365fc44/Hawker_Hurricane_1_G-HRLI_11-20.pdf

 

[MIflyer]

Interestingly enough. the CG chart has a list of things that are easy to remove and not so easy to remove, with weights for each.

 

[Greyman]

Official wording:

The Datum point is the centre of the engine starting handle shaft, and is 26" forward of the leading edge of the aerofoil section at the outer wing inner end rib.

Mk.I (10 Oct 1939)
Approved limits of C.G. travel are 55" to 58" aft of the Datum for an aircraft with a two-bladed wooden airscrew and 53" to 56" aft of the Datum for an aircraft with a three bladed metal variable pitch airscrew. The limiting positions are measured parallel with the thrust line.

Mk.I (17 Mar 1941)
Approved limits of C.G. travel are 53" to 58" aft of the Datum point. The limiting positions are measured parallel with the thrust line.

Mk.I (8 Jun 1942)
Approved limits of C.G. travel are 54" to 57" aft of the Datum for an aircraft with a Rotol propeller and 53" to 56" aft of the Datum for an aircraft with a De Havilland Constant Speed Propeller airscrew. The limiting positions are measured parallel with the thrust line.

I assume the '41 limit is for the (at that time) ubiquitous Rotol Hurricane.

 

[ThomasP]

Hey Mlflyer,

I would very much appreciate a copy of the Hurricane Mk II CG chart if you would post it.

 

[SaparotRob]

It is briefly discussed here Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)
Post no 2510

Adding armour plate to the Hurricane moved the CoG rearwards, fitting the Variable pitch prop moved it forward again.

Posted in error.

 

[pbehn]

Posted in error.

OK

 

[SaparotRob]

No it wasnt, the installation of pilot armour in the Hurricane Mk I and the effect on CoG is in that post, click on the link.

No, my fat finger hit the reply button by accident.

 

[dreameruk]

Official wording:

The Datum point is the centre of the engine starting handle shaft, and is 26" forward of the leading edge of the aerofoil section at the outer wing inner end rib.

Mk.I (10 Oct 1939)
Approved limits of C.G. travel are 55" to 58" aft of the Datum for an aircraft with a two-bladed wooden airscrew and 53" to 56" aft of the Datum for an aircraft with a three bladed metal variable pitch airscrew. The limiting positions are measured parallel with the thrust line.

Mk.I (17 Mar 1941)
Approved limits of C.G. travel are 53" to 58" aft of the Datum point. The limiting positions are measured parallel with the thrust line.

Mk.I (8 Jun 1942)
Approved limits of C.G. travel are 54" to 57" aft of the Datum for an aircraft with a Rotol propeller and 53" to 56" aft of the Datum for an aircraft with a De Havilland Constant Speed Propeller airscrew. The limiting positions are measured parallel with the thrust line.

I assume the '41 limit is for the (at that time) ubiquitous Rotol Hurricane.

thank you, now for the next one lol. how would i go about changing these to % ? would anyone know ? it needs to be % as its for a msfs 2020 plane. thanks again all.

 

[MIflyer]

Here is the Hurri II Data.

 

[ThomasP]

Thanks Mlflyer.

 

[VLPhoenix]

thank you, now for the next one lol. how would i go about changing these to % ? would anyone know ? it needs to be % as its for a msfs 2020 plane. thanks again all.

The numbers given here in this thread refer to absolute dimensions from a reference point on the fuselage, so that ground crews can check during weighing procedure.
CG given as percentage is the underlying aerodynamic theoretical value and refers to %MAC (% mean aerodynamic chord). To get to those percentages you first need to find the absolute position of the mean aerodynamic wing chord. A non-rectangular wing has to be recalculated as if it were a rectangular wing with the same lifting properties. The resulting airfoil chord length of this theoretical wing is the mean aerodynamic chord length. Depending on the wing geometry (sweeping angles of leading edge & trailing edge) it will not sit at the same position as the actual wing.
Now as you have the absolute position of the mean aerodynamic chord and its length you can overlay the absolute positions of the fwd and aft CG limits.
The percentage value refers to the position of the CG limit in relation to the MAC (the MAC leading edge point being 0%, the MAC trailing edge being the 100%).
According to NACA Wartime Report L-565 from 1942 testing a Hawker Hurricane Mk.II, Reg. Z2963, MAC length was 84.6 in., position of MAC was approx. 5.2 in. behind leading edge wing.

 

[dreameruk]

The numbers given here in this thread refer to absolute dimensions from a reference point on the fuselage, so that ground crews can check during weighing procedure.
CG given as percentage is the underlying aerodynamic theoretical value and refers to %MAC (% mean aerodynamic chord). To get to those percentages you first need to find the absolute position of the mean aerodynamic wing chord. A non-rectangular wing has to be recalculated as if it were a rectangular wing with the same lifting properties. The resulting airfoil chord length of this theoretical wing is the mean aerodynamic chord length. Depending on the wing geometry (sweeping angles of leading edge & trailing edge) it will not sit at the same position as the actual wing.
Now as you have the absolute position of the mean aerodynamic chord and its length you can overlay the absolute positions of the fwd and aft CG limits.
The percentage value refers to the position of the CG limit in relation to the MAC (the MAC leading edge point being 0%, the MAC trailing edge being the 100%).
According to NACA Wartime Report L-565 from 1942 testing a Hawker Hurricane Mk.II, Reg. Z2963, MAC length was 84.6 in., position of MAC was approx. 5.2 in. behind leading edge wing.

sorry for the late reply, just got back from being away for a few days. Thank you will see if i can get my brain into gear and work it out, thanks again all.

 

[MiTasol]

I have just posted a Hurricane Mk I manual at Hawker Hurricane Manuals It was supposed to be in Technical but that address suggest it is in a higher level

It does not have the CG chart but it has a good photo showing the location of the starter socket on the second last page. I scanned in colour by mistake and would probably have got a better copy if I had used greyscale.

Hopefully MIFlyer can eventually scan and add his Mk II manual at some time in the future